DBD-SQLite

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sqlite3.c  view on Meta::CPAN

** ^This interface causes the xEntryPoint() function to be invoked for
** each new [database connection] that is created.  The idea here is that
** xEntryPoint() is the entry point for a statically linked [SQLite extension]
** that is to be automatically loaded into all new database connections.
**
** ^(Even though the function prototype shows that xEntryPoint() takes
** no arguments and returns void, SQLite invokes xEntryPoint() with three
** arguments and expects an integer result as if the signature of the
** entry point were as follows:
**
** <blockquote><pre>
** &nbsp;  int xEntryPoint(
** &nbsp;    sqlite3 *db,
** &nbsp;    const char **pzErrMsg,
** &nbsp;    const struct sqlite3_api_routines *pThunk
** &nbsp;  );
** </pre></blockquote>)^
**
** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
** point to an appropriate error message (obtained from [sqlite3_mprintf()])
** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
** is NULL before calling the xEntryPoint().  ^SQLite will invoke
** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
**
** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
** on the list of automatic extensions is a harmless no-op. ^No entry point
** will be called more than once for each database connection that is opened.
**
** See also: [sqlite3_reset_auto_extension()]
** and [sqlite3_cancel_auto_extension()]
*/
SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));

/*
** CAPI3REF: Cancel Automatic Extension Loading
**
** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
** initialization routine X that was registered using a prior call to
** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
** routine returns 1 if initialization routine X was successfully
** unregistered and it returns 0 if X was not on the list of initialization
** routines.
*/
SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));

/*
** CAPI3REF: Reset Automatic Extension Loading
**
** ^This interface disables all automatic extensions previously
** registered using [sqlite3_auto_extension()].
*/
SQLITE_API void sqlite3_reset_auto_extension(void);

/*
** Structures used by the virtual table interface
*/
typedef struct sqlite3_vtab sqlite3_vtab;
typedef struct sqlite3_index_info sqlite3_index_info;
typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
typedef struct sqlite3_module sqlite3_module;

/*
** CAPI3REF: Virtual Table Object
** KEYWORDS: sqlite3_module {virtual table module}
**
** This structure, sometimes called a "virtual table module",
** defines the implementation of a [virtual table].
** This structure consists mostly of methods for the module.
**
** ^A virtual table module is created by filling in a persistent
** instance of this structure and passing a pointer to that instance
** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
** ^The registration remains valid until it is replaced by a different
** module or until the [database connection] closes.  The content
** of this structure must not change while it is registered with
** any database connection.
*/
struct sqlite3_module {
  int iVersion;
  int (*xCreate)(sqlite3*, void *pAux,
               int argc, const char *const*argv,
               sqlite3_vtab **ppVTab, char**);
  int (*xConnect)(sqlite3*, void *pAux,
               int argc, const char *const*argv,
               sqlite3_vtab **ppVTab, char**);
  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
  int (*xDisconnect)(sqlite3_vtab *pVTab);
  int (*xDestroy)(sqlite3_vtab *pVTab);
  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
  int (*xClose)(sqlite3_vtab_cursor*);
  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
                int argc, sqlite3_value **argv);
  int (*xNext)(sqlite3_vtab_cursor*);
  int (*xEof)(sqlite3_vtab_cursor*);
  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
  int (*xBegin)(sqlite3_vtab *pVTab);
  int (*xSync)(sqlite3_vtab *pVTab);
  int (*xCommit)(sqlite3_vtab *pVTab);
  int (*xRollback)(sqlite3_vtab *pVTab);
  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
                       void **ppArg);
  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
  /* The methods above are in version 1 of the sqlite_module object. Those
  ** below are for version 2 and greater. */
  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
  int (*xRelease)(sqlite3_vtab *pVTab, int);
  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
  /* The methods above are in versions 1 and 2 of the sqlite_module object.
  ** Those below are for version 3 and greater. */
  int (*xShadowName)(const char*);
  /* The methods above are in versions 1 through 3 of the sqlite_module object.
  ** Those below are for version 4 and greater. */
  int (*xIntegrity)(sqlite3_vtab *pVTab, const char *zSchema,
                    const char *zTabName, int mFlags, char **pzErr);
};

/*
** CAPI3REF: Virtual Table Indexing Information
** KEYWORDS: sqlite3_index_info
**
** The sqlite3_index_info structure and its substructures is used as part
** of the [virtual table] interface to
** pass information into and receive the reply from the [xBestIndex]
** method of a [virtual table module].  The fields under **Inputs** are the
** inputs to xBestIndex and are read-only.  xBestIndex inserts its
** results into the **Outputs** fields.
**
** ^(The aConstraint[] array records WHERE clause constraints of the form:
**
** <blockquote>column OP expr</blockquote>
**
** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
** stored in aConstraint[].op using one of the
** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
** ^(The index of the column is stored in
** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
** expr on the right-hand side can be evaluated (and thus the constraint
** is usable) and false if it cannot.)^
**
** ^The optimizer automatically inverts terms of the form "expr OP column"
** and makes other simplifications to the WHERE clause in an attempt to
** get as many WHERE clause terms into the form shown above as possible.
** ^The aConstraint[] array only reports WHERE clause terms that are
** relevant to the particular virtual table being queried.
**
** ^Information about the ORDER BY clause is stored in aOrderBy[].
** ^Each term of aOrderBy records a column of the ORDER BY clause.
**
** The colUsed field indicates which columns of the virtual table may be
** required by the current scan. Virtual table columns are numbered from
** zero in the order in which they appear within the CREATE TABLE statement
** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
** the corresponding bit is set within the colUsed mask if the column may be

sqlite3.c  view on Meta::CPAN

** interface is equivalent to sqlite3_create_module_v2() with a NULL
** destructor.
**
** ^If the third parameter (the pointer to the sqlite3_module object) is
** NULL then no new module is created and any existing modules with the
** same name are dropped.
**
** See also: [sqlite3_drop_modules()]
*/
SQLITE_API int sqlite3_create_module(
  sqlite3 *db,               /* SQLite connection to register module with */
  const char *zName,         /* Name of the module */
  const sqlite3_module *p,   /* Methods for the module */
  void *pClientData          /* Client data for xCreate/xConnect */
);
SQLITE_API int sqlite3_create_module_v2(
  sqlite3 *db,               /* SQLite connection to register module with */
  const char *zName,         /* Name of the module */
  const sqlite3_module *p,   /* Methods for the module */
  void *pClientData,         /* Client data for xCreate/xConnect */
  void(*xDestroy)(void*)     /* Module destructor function */
);

/*
** CAPI3REF: Remove Unnecessary Virtual Table Implementations
** METHOD: sqlite3
**
** ^The sqlite3_drop_modules(D,L) interface removes all virtual
** table modules from database connection D except those named on list L.
** The L parameter must be either NULL or a pointer to an array of pointers
** to strings where the array is terminated by a single NULL pointer.
** ^If the L parameter is NULL, then all virtual table modules are removed.
**
** See also: [sqlite3_create_module()]
*/
SQLITE_API int sqlite3_drop_modules(
  sqlite3 *db,                /* Remove modules from this connection */
  const char **azKeep         /* Except, do not remove the ones named here */
);

/*
** CAPI3REF: Virtual Table Instance Object
** KEYWORDS: sqlite3_vtab
**
** Every [virtual table module] implementation uses a subclass
** of this object to describe a particular instance
** of the [virtual table].  Each subclass will
** be tailored to the specific needs of the module implementation.
** The purpose of this superclass is to define certain fields that are
** common to all module implementations.
**
** ^Virtual tables methods can set an error message by assigning a
** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
** take care that any prior string is freed by a call to [sqlite3_free()]
** prior to assigning a new string to zErrMsg.  ^After the error message
** is delivered up to the client application, the string will be automatically
** freed by sqlite3_free() and the zErrMsg field will be zeroed.
*/
struct sqlite3_vtab {
  const sqlite3_module *pModule;  /* The module for this virtual table */
  int nRef;                       /* Number of open cursors */
  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
  /* Virtual table implementations will typically add additional fields */
};

/*
** CAPI3REF: Virtual Table Cursor Object
** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
**
** Every [virtual table module] implementation uses a subclass of the
** following structure to describe cursors that point into the
** [virtual table] and are used
** to loop through the virtual table.  Cursors are created using the
** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
** of the module.  Each module implementation will define
** the content of a cursor structure to suit its own needs.
**
** This superclass exists in order to define fields of the cursor that
** are common to all implementations.
*/
struct sqlite3_vtab_cursor {
  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
  /* Virtual table implementations will typically add additional fields */
};

/*
** CAPI3REF: Declare The Schema Of A Virtual Table
**
** ^The [xCreate] and [xConnect] methods of a
** [virtual table module] call this interface
** to declare the format (the names and datatypes of the columns) of
** the virtual tables they implement.
*/
SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);

/*
** CAPI3REF: Overload A Function For A Virtual Table
** METHOD: sqlite3
**
** ^(Virtual tables can provide alternative implementations of functions
** using the [xFindFunction] method of the [virtual table module].
** But global versions of those functions
** must exist in order to be overloaded.)^
**
** ^(This API makes sure a global version of a function with a particular
** name and number of parameters exists.  If no such function exists
** before this API is called, a new function is created.)^  ^The implementation
** of the new function always causes an exception to be thrown.  So
** the new function is not good for anything by itself.  Its only
** purpose is to be a placeholder function that can be overloaded
** by a [virtual table].
*/
SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);

/*
** CAPI3REF: A Handle To An Open BLOB
** KEYWORDS: {BLOB handle} {BLOB handles}
**
** An instance of this object represents an open BLOB on which
** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
** ^Objects of this type are created by [sqlite3_blob_open()]
** and destroyed by [sqlite3_blob_close()].
** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
** can be used to read or write small subsections of the BLOB.
** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
*/
typedef struct sqlite3_blob sqlite3_blob;

/*
** CAPI3REF: Open A BLOB For Incremental I/O
** METHOD: sqlite3
** CONSTRUCTOR: sqlite3_blob
**
** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
** in row iRow, column zColumn, table zTable in database zDb;
** in other words, the same BLOB that would be selected by:
**
** <pre>
**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
** </pre>)^
**
** ^(Parameter zDb is not the filename that contains the database, but

sqlite3.c  view on Meta::CPAN

** of this interface is undefined. ^The requested measurement is written into
** a variable pointed to by the "pOut" parameter.
**
** The "flags" parameter must be passed a mask of flags. At present only
** one flag is defined - SQLITE_SCANSTAT_COMPLEX. If SQLITE_SCANSTAT_COMPLEX
** is specified, then status information is available for all elements
** of a query plan that are reported by "EXPLAIN QUERY PLAN" output. If
** SQLITE_SCANSTAT_COMPLEX is not specified, then only query plan elements
** that correspond to query loops (the "SCAN..." and "SEARCH..." elements of
** the EXPLAIN QUERY PLAN output) are available. Invoking API
** sqlite3_stmt_scanstatus() is equivalent to calling
** sqlite3_stmt_scanstatus_v2() with a zeroed flags parameter.
**
** Parameter "idx" identifies the specific query element to retrieve statistics
** for. Query elements are numbered starting from zero. A value of -1 may
** retrieve statistics for the entire query. ^If idx is out of range
** - less than -1 or greater than or equal to the total number of query
** elements used to implement the statement - a non-zero value is returned and
** the variable that pOut points to is unchanged.
**
** See also: [sqlite3_stmt_scanstatus_reset()]
*/
SQLITE_API int sqlite3_stmt_scanstatus(
  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
  int idx,                  /* Index of loop to report on */
  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
  void *pOut                /* Result written here */
);
SQLITE_API int sqlite3_stmt_scanstatus_v2(
  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
  int idx,                  /* Index of loop to report on */
  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
  int flags,                /* Mask of flags defined below */
  void *pOut                /* Result written here */
);

/*
** CAPI3REF: Prepared Statement Scan Status
** KEYWORDS: {scan status flags}
*/
#define SQLITE_SCANSTAT_COMPLEX 0x0001

/*
** CAPI3REF: Zero Scan-Status Counters
** METHOD: sqlite3_stmt
**
** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
**
** This API is only available if the library is built with pre-processor
** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
*/
SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);

/*
** CAPI3REF: Flush caches to disk mid-transaction
** METHOD: sqlite3
**
** ^If a write-transaction is open on [database connection] D when the
** [sqlite3_db_cacheflush(D)] interface is invoked, any dirty
** pages in the pager-cache that are not currently in use are written out
** to disk. A dirty page may be in use if a database cursor created by an
** active SQL statement is reading from it, or if it is page 1 of a database
** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
** interface flushes caches for all schemas - "main", "temp", and
** any [attached] databases.
**
** ^If this function needs to obtain extra database locks before dirty pages
** can be flushed to disk, it does so. ^If those locks cannot be obtained
** immediately and there is a busy-handler callback configured, it is invoked
** in the usual manner. ^If the required lock still cannot be obtained, then
** the database is skipped and an attempt made to flush any dirty pages
** belonging to the next (if any) database. ^If any databases are skipped
** because locks cannot be obtained, but no other error occurs, this
** function returns SQLITE_BUSY.
**
** ^If any other error occurs while flushing dirty pages to disk (for
** example an IO error or out-of-memory condition), then processing is
** abandoned and an SQLite [error code] is returned to the caller immediately.
**
** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
**
** ^This function does not set the database handle error code or message
** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
*/
SQLITE_API int sqlite3_db_cacheflush(sqlite3*);

/*
** CAPI3REF: The pre-update hook.
** METHOD: sqlite3
**
** ^These interfaces are only available if SQLite is compiled using the
** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
**
** ^The [sqlite3_preupdate_hook()] interface registers a callback function
** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
** on a database table.
** ^At most one preupdate hook may be registered at a time on a single
** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
** the previous setting.
** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
** with a NULL pointer as the second parameter.
** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
** the first parameter to callbacks.
**
** ^The preupdate hook only fires for changes to real database tables; the
** preupdate hook is not invoked for changes to [virtual tables] or to
** system tables like sqlite_sequence or sqlite_stat1.
**
** ^The second parameter to the preupdate callback is a pointer to
** the [database connection] that registered the preupdate hook.
** ^The third parameter to the preupdate callback is one of the constants
** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
** kind of update operation that is about to occur.
** ^(The fourth parameter to the preupdate callback is the name of the
** database within the database connection that is being modified.  This
** will be "main" for the main database or "temp" for TEMP tables or
** the name given after the AS keyword in the [ATTACH] statement for attached
** databases.)^
** ^The fifth parameter to the preupdate callback is the name of the
** table that is being modified.
**

sqlite3.c  view on Meta::CPAN

*/
struct sqlite3_rtree_query_info {
  void *pContext;                   /* pContext from when function registered */
  int nParam;                       /* Number of function parameters */
  sqlite3_rtree_dbl *aParam;        /* value of function parameters */
  void *pUser;                      /* callback can use this, if desired */
  void (*xDelUser)(void*);          /* function to free pUser */
  sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
  unsigned int *anQueue;            /* Number of pending entries in the queue */
  int nCoord;                       /* Number of coordinates */
  int iLevel;                       /* Level of current node or entry */
  int mxLevel;                      /* The largest iLevel value in the tree */
  sqlite3_int64 iRowid;             /* Rowid for current entry */
  sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
  int eParentWithin;                /* Visibility of parent node */
  int eWithin;                      /* OUT: Visibility */
  sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
  /* The following fields are only available in 3.8.11 and later */
  sqlite3_value **apSqlParam;       /* Original SQL values of parameters */
};

/*
** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
*/
#define NOT_WITHIN       0   /* Object completely outside of query region */
#define PARTLY_WITHIN    1   /* Object partially overlaps query region */
#define FULLY_WITHIN     2   /* Object fully contained within query region */


#if 0
}  /* end of the 'extern "C"' block */
#endif

#endif  /* ifndef _SQLITE3RTREE_H_ */

/******** End of sqlite3rtree.h *********/
/******** Begin file sqlite3session.h *********/

#if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
#define __SQLITESESSION_H_ 1

/*
** Make sure we can call this stuff from C++.
*/
#if 0
extern "C" {
#endif


/*
** CAPI3REF: Session Object Handle
**
** An instance of this object is a [session] that can be used to
** record changes to a database.
*/
typedef struct sqlite3_session sqlite3_session;

/*
** CAPI3REF: Changeset Iterator Handle
**
** An instance of this object acts as a cursor for iterating
** over the elements of a [changeset] or [patchset].
*/
typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;

/*
** CAPI3REF: Create A New Session Object
** CONSTRUCTOR: sqlite3_session
**
** Create a new session object attached to database handle db. If successful,
** a pointer to the new object is written to *ppSession and SQLITE_OK is
** returned. If an error occurs, *ppSession is set to NULL and an SQLite
** error code (e.g. SQLITE_NOMEM) is returned.
**
** It is possible to create multiple session objects attached to a single
** database handle.
**
** Session objects created using this function should be deleted using the
** [sqlite3session_delete()] function before the database handle that they
** are attached to is itself closed. If the database handle is closed before
** the session object is deleted, then the results of calling any session
** module function, including [sqlite3session_delete()] on the session object
** are undefined.
**
** Because the session module uses the [sqlite3_preupdate_hook()] API, it
** is not possible for an application to register a pre-update hook on a
** database handle that has one or more session objects attached. Nor is
** it possible to create a session object attached to a database handle for
** which a pre-update hook is already defined. The results of attempting
** either of these things are undefined.
**
** The session object will be used to create changesets for tables in
** database zDb, where zDb is either "main", or "temp", or the name of an
** attached database. It is not an error if database zDb is not attached
** to the database when the session object is created.
*/
SQLITE_API int sqlite3session_create(
  sqlite3 *db,                    /* Database handle */
  const char *zDb,                /* Name of db (e.g. "main") */
  sqlite3_session **ppSession     /* OUT: New session object */
);

/*
** CAPI3REF: Delete A Session Object
** DESTRUCTOR: sqlite3_session
**
** Delete a session object previously allocated using
** [sqlite3session_create()]. Once a session object has been deleted, the
** results of attempting to use pSession with any other session module
** function are undefined.
**
** Session objects must be deleted before the database handle to which they
** are attached is closed. Refer to the documentation for
** [sqlite3session_create()] for details.
*/
SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);

/*
** CAPI3REF: Configure a Session Object
** METHOD: sqlite3_session
**

sqlite3.c  view on Meta::CPAN

SQLITE_PRIVATE int sqlite3BtreeIncrVacuum(Btree *);

/* The flags parameter to sqlite3BtreeCreateTable can be the bitwise OR
** of the flags shown below.
**
** Every SQLite table must have either BTREE_INTKEY or BTREE_BLOBKEY set.
** With BTREE_INTKEY, the table key is a 64-bit integer and arbitrary data
** is stored in the leaves.  (BTREE_INTKEY is used for SQL tables.)  With
** BTREE_BLOBKEY, the key is an arbitrary BLOB and no content is stored
** anywhere - the key is the content.  (BTREE_BLOBKEY is used for SQL
** indices.)
*/
#define BTREE_INTKEY     1    /* Table has only 64-bit signed integer keys */
#define BTREE_BLOBKEY    2    /* Table has keys only - no data */

SQLITE_PRIVATE int sqlite3BtreeDropTable(Btree*, int, int*);
SQLITE_PRIVATE int sqlite3BtreeClearTable(Btree*, int, i64*);
SQLITE_PRIVATE int sqlite3BtreeClearTableOfCursor(BtCursor*);
SQLITE_PRIVATE int sqlite3BtreeTripAllCursors(Btree*, int, int);

SQLITE_PRIVATE void sqlite3BtreeGetMeta(Btree *pBtree, int idx, u32 *pValue);
SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value);

SQLITE_PRIVATE int sqlite3BtreeNewDb(Btree *p);

/*
** The second parameter to sqlite3BtreeGetMeta or sqlite3BtreeUpdateMeta
** should be one of the following values. The integer values are assigned
** to constants so that the offset of the corresponding field in an
** SQLite database header may be found using the following formula:
**
**   offset = 36 + (idx * 4)
**
** For example, the free-page-count field is located at byte offset 36 of
** the database file header. The incr-vacuum-flag field is located at
** byte offset 64 (== 36+4*7).
**
** The BTREE_DATA_VERSION value is not really a value stored in the header.
** It is a read-only number computed by the pager.  But we merge it with
** the header value access routines since its access pattern is the same.
** Call it a "virtual meta value".
*/
#define BTREE_FREE_PAGE_COUNT     0
#define BTREE_SCHEMA_VERSION      1
#define BTREE_FILE_FORMAT         2
#define BTREE_DEFAULT_CACHE_SIZE  3
#define BTREE_LARGEST_ROOT_PAGE   4
#define BTREE_TEXT_ENCODING       5
#define BTREE_USER_VERSION        6
#define BTREE_INCR_VACUUM         7
#define BTREE_APPLICATION_ID      8
#define BTREE_DATA_VERSION        15  /* A virtual meta-value */

/*
** Kinds of hints that can be passed into the sqlite3BtreeCursorHint()
** interface.
**
** BTREE_HINT_RANGE  (arguments: Expr*, Mem*)
**
**     The first argument is an Expr* (which is guaranteed to be constant for
**     the lifetime of the cursor) that defines constraints on which rows
**     might be fetched with this cursor.  The Expr* tree may contain
**     TK_REGISTER nodes that refer to values stored in the array of registers
**     passed as the second parameter.  In other words, if Expr.op==TK_REGISTER
**     then the value of the node is the value in Mem[pExpr.iTable].  Any
**     TK_COLUMN node in the expression tree refers to the Expr.iColumn-th
**     column of the b-tree of the cursor.  The Expr tree will not contain
**     any function calls nor subqueries nor references to b-trees other than
**     the cursor being hinted.
**
**     The design of the _RANGE hint is aid b-tree implementations that try
**     to prefetch content from remote machines - to provide those
**     implementations with limits on what needs to be prefetched and thereby
**     reduce network bandwidth.
**
** Note that BTREE_HINT_FLAGS with BTREE_BULKLOAD is the only hint used by
** standard SQLite.  The other hints are provided for extensions that use
** the SQLite parser and code generator but substitute their own storage
** engine.
*/
#define BTREE_HINT_RANGE 0       /* Range constraints on queries */

/*
** Values that may be OR'd together to form the argument to the
** BTREE_HINT_FLAGS hint for sqlite3BtreeCursorHint():
**
** The BTREE_BULKLOAD flag is set on index cursors when the index is going
** to be filled with content that is already in sorted order.
**
** The BTREE_SEEK_EQ flag is set on cursors that will get OP_SeekGE or
** OP_SeekLE opcodes for a range search, but where the range of entries
** selected will all have the same key.  In other words, the cursor will
** be used only for equality key searches.
**
*/
#define BTREE_BULKLOAD 0x00000001  /* Used to full index in sorted order */
#define BTREE_SEEK_EQ  0x00000002  /* EQ seeks only - no range seeks */

/*
** Flags passed as the third argument to sqlite3BtreeCursor().
**
** For read-only cursors the wrFlag argument is always zero. For read-write
** cursors it may be set to either (BTREE_WRCSR|BTREE_FORDELETE) or just
** (BTREE_WRCSR). If the BTREE_FORDELETE bit is set, then the cursor will
** only be used by SQLite for the following:
**
**   * to seek to and then delete specific entries, and/or
**
**   * to read values that will be used to create keys that other
**     BTREE_FORDELETE cursors will seek to and delete.
**
** The BTREE_FORDELETE flag is an optimization hint.  It is not used by
** by this, the native b-tree engine of SQLite, but it is available to
** alternative storage engines that might be substituted in place of this
** b-tree system.  For alternative storage engines in which a delete of
** the main table row automatically deletes corresponding index rows,
** the FORDELETE flag hint allows those alternative storage engines to
** skip a lot of work.  Namely:  FORDELETE cursors may treat all SEEK
** and DELETE operations as no-ops, and any READ operation against a
** FORDELETE cursor may return a null row: 0x01 0x00.
*/
#define BTREE_WRCSR     0x00000004     /* read-write cursor */
#define BTREE_FORDELETE 0x00000008     /* Cursor is for seek/delete only */

SQLITE_PRIVATE int sqlite3BtreeCursor(
  Btree*,                              /* BTree containing table to open */
  Pgno iTable,                         /* Index of root page */
  int wrFlag,                          /* 1 for writing.  0 for read-only */
  struct KeyInfo*,                     /* First argument to compare function */
  BtCursor *pCursor                    /* Space to write cursor structure */
);
SQLITE_PRIVATE BtCursor *sqlite3BtreeFakeValidCursor(void);
SQLITE_PRIVATE int sqlite3BtreeCursorSize(void);
#ifdef SQLITE_DEBUG
SQLITE_PRIVATE int sqlite3BtreeClosesWithCursor(Btree*,BtCursor*);
#endif
SQLITE_PRIVATE void sqlite3BtreeCursorZero(BtCursor*);
SQLITE_PRIVATE void sqlite3BtreeCursorHintFlags(BtCursor*, unsigned);
#ifdef SQLITE_ENABLE_CURSOR_HINTS
SQLITE_PRIVATE void sqlite3BtreeCursorHint(BtCursor*, int, ...);
#endif

SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor*);
SQLITE_PRIVATE int sqlite3BtreeTableMoveto(
  BtCursor*,
  i64 intKey,
  int bias,
  int *pRes
);
SQLITE_PRIVATE int sqlite3BtreeIndexMoveto(
  BtCursor*,
  UnpackedRecord *pUnKey,
  int *pRes
);
SQLITE_PRIVATE int sqlite3BtreeCursorHasMoved(BtCursor*);
SQLITE_PRIVATE int sqlite3BtreeCursorRestore(BtCursor*, int*);
SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor*, u8 flags);

/* Allowed flags for sqlite3BtreeDelete() and sqlite3BtreeInsert() */
#define BTREE_SAVEPOSITION 0x02  /* Leave cursor pointing at NEXT or PREV */
#define BTREE_AUXDELETE    0x04  /* not the primary delete operation */
#define BTREE_APPEND       0x08  /* Insert is likely an append */
#define BTREE_PREFORMAT    0x80  /* Inserted data is a preformated cell */

/* An instance of the BtreePayload object describes the content of a single
** entry in either an index or table btree.
**
** Index btrees (used for indexes and also WITHOUT ROWID tables) contain
** an arbitrary key and no data.  These btrees have pKey,nKey set to the
** key and the pData,nData,nZero fields are uninitialized.  The aMem,nMem
** fields give an array of Mem objects that are a decomposition of the key.
** The nMem field might be zero, indicating that no decomposition is available.
**
** Table btrees (used for rowid tables) contain an integer rowid used as
** the key and passed in the nKey field.  The pKey field is zero.
** pData,nData hold the content of the new entry.  nZero extra zero bytes
** are appended to the end of the content when constructing the entry.
** The aMem,nMem fields are uninitialized for table btrees.
**
** Field usage summary:
**
**               Table BTrees                   Index Btrees
**
**   pKey        always NULL                    encoded key
**   nKey        the ROWID                      length of pKey
**   pData       data                           not used
**   aMem        not used                       decomposed key value
**   nMem        not used                       entries in aMem
**   nData       length of pData                not used
**   nZero       extra zeros after pData        not used
**
** This object is used to pass information into sqlite3BtreeInsert().  The
** same information used to be passed as five separate parameters.  But placing
** the information into this object helps to keep the interface more
** organized and understandable, and it also helps the resulting code to
** run a little faster by using fewer registers for parameter passing.
*/
struct BtreePayload {
  const void *pKey;       /* Key content for indexes.  NULL for tables */
  sqlite3_int64 nKey;     /* Size of pKey for indexes.  PRIMARY KEY for tabs */
  const void *pData;      /* Data for tables. */
  sqlite3_value *aMem;    /* First of nMem value in the unpacked pKey */
  u16 nMem;               /* Number of aMem[] value.  Might be zero */
  int nData;              /* Size of pData.  0 if none. */
  int nZero;              /* Extra zero data appended after pData,nData */
};

SQLITE_PRIVATE int sqlite3BtreeInsert(BtCursor*, const BtreePayload *pPayload,
                       int flags, int seekResult);
SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor*, int *pRes);
SQLITE_PRIVATE int sqlite3BtreeIsEmpty(BtCursor *pCur, int *pRes);
SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor*, int *pRes);
SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor*, int flags);
SQLITE_PRIVATE int sqlite3BtreeEof(BtCursor*);
SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor*, int flags);
SQLITE_PRIVATE i64 sqlite3BtreeIntegerKey(BtCursor*);
SQLITE_PRIVATE void sqlite3BtreeCursorPin(BtCursor*);
SQLITE_PRIVATE void sqlite3BtreeCursorUnpin(BtCursor*);
SQLITE_PRIVATE i64 sqlite3BtreeOffset(BtCursor*);
SQLITE_PRIVATE int sqlite3BtreePayload(BtCursor*, u32 offset, u32 amt, void*);

sqlite3.c  view on Meta::CPAN

  char *zAff;         /* Affinity of the overall IN expression */
  int iTable;         /* Ephemeral table generated by the subroutine */
  int iAddr;          /* Subroutine entry address */
  int regReturn;      /* Register used to hold return address */
};

/*
** A single instruction of the virtual machine has an opcode
** and as many as three operands.  The instruction is recorded
** as an instance of the following structure:
*/
struct VdbeOp {
  u8 opcode;          /* What operation to perform */
  signed char p4type; /* One of the P4_xxx constants for p4 */
  u16 p5;             /* Fifth parameter is an unsigned 16-bit integer */
  int p1;             /* First operand */
  int p2;             /* Second parameter (often the jump destination) */
  int p3;             /* The third parameter */
  union p4union {     /* fourth parameter */
    int i;                 /* Integer value if p4type==P4_INT32 */
    void *p;               /* Generic pointer */
    char *z;               /* Pointer to data for string (char array) types */
    i64 *pI64;             /* Used when p4type is P4_INT64 */
    double *pReal;         /* Used when p4type is P4_REAL */
    FuncDef *pFunc;        /* Used when p4type is P4_FUNCDEF */
    sqlite3_context *pCtx; /* Used when p4type is P4_FUNCCTX */
    CollSeq *pColl;        /* Used when p4type is P4_COLLSEQ */
    Mem *pMem;             /* Used when p4type is P4_MEM */
    VTable *pVtab;         /* Used when p4type is P4_VTAB */
    KeyInfo *pKeyInfo;     /* Used when p4type is P4_KEYINFO */
    u32 *ai;               /* Used when p4type is P4_INTARRAY */
    SubProgram *pProgram;  /* Used when p4type is P4_SUBPROGRAM */
    Table *pTab;           /* Used when p4type is P4_TABLE */
    SubrtnSig *pSubrtnSig; /* Used when p4type is P4_SUBRTNSIG */
#ifdef SQLITE_ENABLE_CURSOR_HINTS
    Expr *pExpr;           /* Used when p4type is P4_EXPR */
#endif
  } p4;
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
  char *zComment;          /* Comment to improve readability */
#endif
#ifdef SQLITE_VDBE_COVERAGE
  u32 iSrcLine;            /* Source-code line that generated this opcode
                           ** with flags in the upper 8 bits */
#endif
#if defined(SQLITE_ENABLE_STMT_SCANSTATUS) || defined(VDBE_PROFILE)
  u64 nExec;
  u64 nCycle;
#endif
};
typedef struct VdbeOp VdbeOp;


/*
** A sub-routine used to implement a trigger program.
*/
struct SubProgram {
  VdbeOp *aOp;                  /* Array of opcodes for sub-program */
  int nOp;                      /* Elements in aOp[] */
  int nMem;                     /* Number of memory cells required */
  int nCsr;                     /* Number of cursors required */
  u8 *aOnce;                    /* Array of OP_Once flags */
  void *token;                  /* id that may be used to recursive triggers */
  SubProgram *pNext;            /* Next sub-program already visited */
};

/*
** A smaller version of VdbeOp used for the VdbeAddOpList() function because
** it takes up less space.
*/
struct VdbeOpList {
  u8 opcode;          /* What operation to perform */
  signed char p1;     /* First operand */
  signed char p2;     /* Second parameter (often the jump destination) */
  signed char p3;     /* Third parameter */
};
typedef struct VdbeOpList VdbeOpList;

/*
** Allowed values of VdbeOp.p4type
*/
#define P4_NOTUSED      0   /* The P4 parameter is not used */
#define P4_TRANSIENT    0   /* P4 is a pointer to a transient string */
#define P4_STATIC     (-1)  /* Pointer to a static string */
#define P4_COLLSEQ    (-2)  /* P4 is a pointer to a CollSeq structure */
#define P4_INT32      (-3)  /* P4 is a 32-bit signed integer */
#define P4_SUBPROGRAM (-4)  /* P4 is a pointer to a SubProgram structure */
#define P4_TABLE      (-5)  /* P4 is a pointer to a Table structure */
/* Above do not own any resources.  Must free those below */
#define P4_FREE_IF_LE (-6)
#define P4_DYNAMIC    (-6)  /* Pointer to memory from sqliteMalloc() */
#define P4_FUNCDEF    (-7)  /* P4 is a pointer to a FuncDef structure */
#define P4_KEYINFO    (-8)  /* P4 is a pointer to a KeyInfo structure */
#define P4_EXPR       (-9) /* P4 is a pointer to an Expr tree */
#define P4_MEM        (-10) /* P4 is a pointer to a Mem*    structure */
#define P4_VTAB       (-11) /* P4 is a pointer to an sqlite3_vtab structure */
#define P4_REAL       (-12) /* P4 is a 64-bit floating point value */
#define P4_INT64      (-13) /* P4 is a 64-bit signed integer */
#define P4_INTARRAY   (-14) /* P4 is a vector of 32-bit integers */
#define P4_FUNCCTX    (-15) /* P4 is a pointer to an sqlite3_context object */
#define P4_TABLEREF   (-16) /* Like P4_TABLE, but reference counted */
#define P4_SUBRTNSIG  (-17) /* P4 is a SubrtnSig pointer */

/* Error message codes for OP_Halt */
#define P5_ConstraintNotNull 1
#define P5_ConstraintUnique  2
#define P5_ConstraintCheck   3
#define P5_ConstraintFK      4

/*
** The Vdbe.aColName array contains 5n Mem structures, where n is the
** number of columns of data returned by the statement.
*/
#define COLNAME_NAME     0
#define COLNAME_DECLTYPE 1
#define COLNAME_DATABASE 2
#define COLNAME_TABLE    3
#define COLNAME_COLUMN   4
#ifdef SQLITE_ENABLE_COLUMN_METADATA
# define COLNAME_N        5      /* Number of COLNAME_xxx symbols */
#else

sqlite3.c  view on Meta::CPAN

#define OP_Sort           35 /* jump                                       */
#define OP_Rewind         36 /* jump0                                      */
#define OP_IfEmpty        37 /* jump, synopsis: if( empty(P1) ) goto P2    */
#define OP_SorterNext     38 /* jump                                       */
#define OP_Prev           39 /* jump                                       */
#define OP_Next           40 /* jump                                       */
#define OP_IdxLE          41 /* jump, synopsis: key=r[P3@P4]               */
#define OP_IdxGT          42 /* jump, synopsis: key=r[P3@P4]               */
#define OP_Or             43 /* same as TK_OR, synopsis: r[P3]=(r[P1] || r[P2]) */
#define OP_And            44 /* same as TK_AND, synopsis: r[P3]=(r[P1] && r[P2]) */
#define OP_IdxLT          45 /* jump, synopsis: key=r[P3@P4]               */
#define OP_IdxGE          46 /* jump, synopsis: key=r[P3@P4]               */
#define OP_RowSetRead     47 /* jump, synopsis: r[P3]=rowset(P1)           */
#define OP_RowSetTest     48 /* jump, synopsis: if r[P3] in rowset(P1) goto P2 */
#define OP_Program        49 /* jump0                                      */
#define OP_FkIfZero       50 /* jump, synopsis: if fkctr[P1]==0 goto P2    */
#define OP_IsNull         51 /* jump, same as TK_ISNULL, synopsis: if r[P1]==NULL goto P2 */
#define OP_NotNull        52 /* jump, same as TK_NOTNULL, synopsis: if r[P1]!=NULL goto P2 */
#define OP_Ne             53 /* jump, same as TK_NE, synopsis: IF r[P3]!=r[P1] */
#define OP_Eq             54 /* jump, same as TK_EQ, synopsis: IF r[P3]==r[P1] */
#define OP_Gt             55 /* jump, same as TK_GT, synopsis: IF r[P3]>r[P1] */
#define OP_Le             56 /* jump, same as TK_LE, synopsis: IF r[P3]<=r[P1] */
#define OP_Lt             57 /* jump, same as TK_LT, synopsis: IF r[P3]<r[P1] */
#define OP_Ge             58 /* jump, same as TK_GE, synopsis: IF r[P3]>=r[P1] */
#define OP_ElseEq         59 /* jump, same as TK_ESCAPE                    */
#define OP_IfPos          60 /* jump, synopsis: if r[P1]>0 then r[P1]-=P3, goto P2 */
#define OP_IfNotZero      61 /* jump, synopsis: if r[P1]!=0 then r[P1]--, goto P2 */
#define OP_DecrJumpZero   62 /* jump, synopsis: if (--r[P1])==0 goto P2    */
#define OP_IncrVacuum     63 /* jump                                       */
#define OP_VNext          64 /* jump                                       */
#define OP_Filter         65 /* jump, synopsis: if key(P3@P4) not in filter(P1) goto P2 */
#define OP_PureFunc       66 /* synopsis: r[P3]=func(r[P2@NP])             */
#define OP_Function       67 /* synopsis: r[P3]=func(r[P2@NP])             */
#define OP_Return         68
#define OP_EndCoroutine   69
#define OP_HaltIfNull     70 /* synopsis: if r[P3]=null halt               */
#define OP_Halt           71
#define OP_Integer        72 /* synopsis: r[P2]=P1                         */
#define OP_Int64          73 /* synopsis: r[P2]=P4                         */
#define OP_String         74 /* synopsis: r[P2]='P4' (len=P1)              */
#define OP_BeginSubrtn    75 /* synopsis: r[P2]=NULL                       */
#define OP_Null           76 /* synopsis: r[P2..P3]=NULL                   */
#define OP_SoftNull       77 /* synopsis: r[P1]=NULL                       */
#define OP_Blob           78 /* synopsis: r[P2]=P4 (len=P1)                */
#define OP_Variable       79 /* synopsis: r[P2]=parameter(P1)              */
#define OP_Move           80 /* synopsis: r[P2@P3]=r[P1@P3]                */
#define OP_Copy           81 /* synopsis: r[P2@P3+1]=r[P1@P3+1]            */
#define OP_SCopy          82 /* synopsis: r[P2]=r[P1]                      */
#define OP_IntCopy        83 /* synopsis: r[P2]=r[P1]                      */
#define OP_FkCheck        84
#define OP_ResultRow      85 /* synopsis: output=r[P1@P2]                  */
#define OP_CollSeq        86
#define OP_AddImm         87 /* synopsis: r[P1]=r[P1]+P2                   */
#define OP_RealAffinity   88
#define OP_Cast           89 /* synopsis: affinity(r[P1])                  */
#define OP_Permutation    90
#define OP_Compare        91 /* synopsis: r[P1@P3] <-> r[P2@P3]            */
#define OP_IsTrue         92 /* synopsis: r[P2] = coalesce(r[P1]==TRUE,P3) ^ P4 */
#define OP_ZeroOrNull     93 /* synopsis: r[P2] = 0 OR NULL                */
#define OP_Offset         94 /* synopsis: r[P3] = sqlite_offset(P1)        */
#define OP_Column         95 /* synopsis: r[P3]=PX cursor P1 column P2     */
#define OP_TypeCheck      96 /* synopsis: typecheck(r[P1@P2])              */
#define OP_Affinity       97 /* synopsis: affinity(r[P1@P2])               */
#define OP_MakeRecord     98 /* synopsis: r[P3]=mkrec(r[P1@P2])            */
#define OP_Count          99 /* synopsis: r[P2]=count()                    */
#define OP_ReadCookie    100
#define OP_SetCookie     101
#define OP_ReopenIdx     102 /* synopsis: root=P2 iDb=P3                   */
#define OP_BitAnd        103 /* same as TK_BITAND, synopsis: r[P3]=r[P1]&r[P2] */
#define OP_BitOr         104 /* same as TK_BITOR, synopsis: r[P3]=r[P1]|r[P2] */
#define OP_ShiftLeft     105 /* same as TK_LSHIFT, synopsis: r[P3]=r[P2]<<r[P1] */
#define OP_ShiftRight    106 /* same as TK_RSHIFT, synopsis: r[P3]=r[P2]>>r[P1] */
#define OP_Add           107 /* same as TK_PLUS, synopsis: r[P3]=r[P1]+r[P2] */
#define OP_Subtract      108 /* same as TK_MINUS, synopsis: r[P3]=r[P2]-r[P1] */
#define OP_Multiply      109 /* same as TK_STAR, synopsis: r[P3]=r[P1]*r[P2] */
#define OP_Divide        110 /* same as TK_SLASH, synopsis: r[P3]=r[P2]/r[P1] */
#define OP_Remainder     111 /* same as TK_REM, synopsis: r[P3]=r[P2]%r[P1] */
#define OP_Concat        112 /* same as TK_CONCAT, synopsis: r[P3]=r[P2]+r[P1] */
#define OP_OpenRead      113 /* synopsis: root=P2 iDb=P3                   */
#define OP_OpenWrite     114 /* synopsis: root=P2 iDb=P3                   */
#define OP_BitNot        115 /* same as TK_BITNOT, synopsis: r[P2]= ~r[P1] */
#define OP_OpenDup       116
#define OP_OpenAutoindex 117 /* synopsis: nColumn=P2                       */
#define OP_String8       118 /* same as TK_STRING, synopsis: r[P2]='P4'    */
#define OP_OpenEphemeral 119 /* synopsis: nColumn=P2                       */
#define OP_SorterOpen    120
#define OP_SequenceTest  121 /* synopsis: if( cursor[P1].ctr++ ) pc = P2   */
#define OP_OpenPseudo    122 /* synopsis: P3 columns in r[P2]              */
#define OP_Close         123
#define OP_ColumnsUsed   124
#define OP_SeekScan      125 /* synopsis: Scan-ahead up to P1 rows         */
#define OP_SeekHit       126 /* synopsis: set P2<=seekHit<=P3              */
#define OP_Sequence      127 /* synopsis: r[P2]=cursor[P1].ctr++           */
#define OP_NewRowid      128 /* synopsis: r[P2]=rowid                      */
#define OP_Insert        129 /* synopsis: intkey=r[P3] data=r[P2]          */
#define OP_RowCell       130
#define OP_Delete        131
#define OP_ResetCount    132
#define OP_SorterCompare 133 /* synopsis: if key(P1)!=trim(r[P3],P4) goto P2 */
#define OP_SorterData    134 /* synopsis: r[P2]=data                       */
#define OP_RowData       135 /* synopsis: r[P2]=data                       */
#define OP_Rowid         136 /* synopsis: r[P2]=PX rowid of P1             */
#define OP_NullRow       137
#define OP_SeekEnd       138
#define OP_IdxInsert     139 /* synopsis: key=r[P2]                        */
#define OP_SorterInsert  140 /* synopsis: key=r[P2]                        */
#define OP_IdxDelete     141 /* synopsis: key=r[P2@P3]                     */
#define OP_DeferredSeek  142 /* synopsis: Move P3 to P1.rowid if needed    */
#define OP_IdxRowid      143 /* synopsis: r[P2]=rowid                      */
#define OP_FinishSeek    144
#define OP_Destroy       145
#define OP_Clear         146
#define OP_ResetSorter   147
#define OP_CreateBtree   148 /* synopsis: r[P2]=root iDb=P1 flags=P3       */
#define OP_SqlExec       149
#define OP_ParseSchema   150
#define OP_LoadAnalysis  151
#define OP_DropTable     152
#define OP_DropIndex     153
#define OP_Real          154 /* same as TK_FLOAT, synopsis: r[P2]=P4       */
#define OP_DropTrigger   155
#define OP_IntegrityCk   156
#define OP_RowSetAdd     157 /* synopsis: rowset(P1)=r[P2]                 */
#define OP_Param         158
#define OP_FkCounter     159 /* synopsis: fkctr[P1]+=P2                    */
#define OP_MemMax        160 /* synopsis: r[P1]=max(r[P1],r[P2])           */
#define OP_OffsetLimit   161 /* synopsis: if r[P1]>0 then r[P2]=r[P1]+max(0,r[P3]) else r[P2]=(-1) */
#define OP_AggInverse    162 /* synopsis: accum=r[P3] inverse(r[P2@P5])    */
#define OP_AggStep       163 /* synopsis: accum=r[P3] step(r[P2@P5])       */
#define OP_AggStep1      164 /* synopsis: accum=r[P3] step(r[P2@P5])       */
#define OP_AggValue      165 /* synopsis: r[P3]=value N=P2                 */
#define OP_AggFinal      166 /* synopsis: accum=r[P1] N=P2                 */
#define OP_Expire        167
#define OP_CursorLock    168
#define OP_CursorUnlock  169
#define OP_TableLock     170 /* synopsis: iDb=P1 root=P2 write=P3          */
#define OP_VBegin        171
#define OP_VCreate       172
#define OP_VDestroy      173
#define OP_VOpen         174
#define OP_VCheck        175
#define OP_VInitIn       176 /* synopsis: r[P2]=ValueList(P1,P3)           */
#define OP_VColumn       177 /* synopsis: r[P3]=vcolumn(P2)                */
#define OP_VRename       178
#define OP_Pagecount     179
#define OP_MaxPgcnt      180
#define OP_ClrSubtype    181 /* synopsis: r[P1].subtype = 0                */
#define OP_GetSubtype    182 /* synopsis: r[P2] = r[P1].subtype            */
#define OP_SetSubtype    183 /* synopsis: r[P2].subtype = r[P1]            */
#define OP_FilterAdd     184 /* synopsis: filter(P1) += key(P3@P4)         */
#define OP_Trace         185
#define OP_CursorHint    186
#define OP_ReleaseReg    187 /* synopsis: release r[P1@P2] mask P3         */

sqlite3.c  view on Meta::CPAN

** Macros to compute aCol[] and aFunc[] register numbers.
**
** These macros should not be used prior to the call to
** assignAggregateRegisters() that computes the value of pAggInfo->iFirstReg.
** The assert()s that are part of this macro verify that constraint.
*/
#ifndef NDEBUG
#define AggInfoColumnReg(A,I)  (assert((A)->iFirstReg),(A)->iFirstReg+(I))
#define AggInfoFuncReg(A,I)    \
                      (assert((A)->iFirstReg),(A)->iFirstReg+(A)->nColumn+(I))
#else
#define AggInfoColumnReg(A,I)  ((A)->iFirstReg+(I))
#define AggInfoFuncReg(A,I)    \
                      ((A)->iFirstReg+(A)->nColumn+(I))
#endif

/*
** The datatype ynVar is a signed integer, either 16-bit or 32-bit.
** Usually it is 16-bits.  But if SQLITE_MAX_VARIABLE_NUMBER is greater
** than 32767 we have to make it 32-bit.  16-bit is preferred because
** it uses less memory in the Expr object, which is a big memory user
** in systems with lots of prepared statements.  And few applications
** need more than about 10 or 20 variables.  But some extreme users want
** to have prepared statements with over 32766 variables, and for them
** the option is available (at compile-time).
*/
#if SQLITE_MAX_VARIABLE_NUMBER<32767
typedef i16 ynVar;
#else
typedef int ynVar;
#endif

/*
** Each node of an expression in the parse tree is an instance
** of this structure.
**
** Expr.op is the opcode. The integer parser token codes are reused
** as opcodes here. For example, the parser defines TK_GE to be an integer
** code representing the ">=" operator. This same integer code is reused
** to represent the greater-than-or-equal-to operator in the expression
** tree.
**
** If the expression is an SQL literal (TK_INTEGER, TK_FLOAT, TK_BLOB,
** or TK_STRING), then Expr.u.zToken contains the text of the SQL literal. If
** the expression is a variable (TK_VARIABLE), then Expr.u.zToken contains the
** variable name. Finally, if the expression is an SQL function (TK_FUNCTION),
** then Expr.u.zToken contains the name of the function.
**
** Expr.pRight and Expr.pLeft are the left and right subexpressions of a
** binary operator. Either or both may be NULL.
**
** Expr.x.pList is a list of arguments if the expression is an SQL function,
** a CASE expression or an IN expression of the form "<lhs> IN (<y>, <z>...)".
** Expr.x.pSelect is used if the expression is a sub-select or an expression of
** the form "<lhs> IN (SELECT ...)". If the EP_xIsSelect bit is set in the
** Expr.flags mask, then Expr.x.pSelect is valid. Otherwise, Expr.x.pList is
** valid.
**
** An expression of the form ID or ID.ID refers to a column in a table.
** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is
** the integer cursor number of a VDBE cursor pointing to that table and
** Expr.iColumn is the column number for the specific column.  If the
** expression is used as a result in an aggregate SELECT, then the
** value is also stored in the Expr.iAgg column in the aggregate so that
** it can be accessed after all aggregates are computed.
**
** If the expression is an unbound variable marker (a question mark
** character '?' in the original SQL) then the Expr.iTable holds the index
** number for that variable.
**
** If the expression is a subquery then Expr.iColumn holds an integer
** register number containing the result of the subquery.  If the
** subquery gives a constant result, then iTable is -1.  If the subquery
** gives a different answer at different times during statement processing
** then iTable is the address of a subroutine that computes the subquery.
**
** If the Expr is of type OP_Column, and the table it is selecting from
** is a disk table or the "old.*" pseudo-table, then pTab points to the
** corresponding table definition.
**
** ALLOCATION NOTES:
**
** Expr objects can use a lot of memory space in database schema.  To
** help reduce memory requirements, sometimes an Expr object will be
** truncated.  And to reduce the number of memory allocations, sometimes
** two or more Expr objects will be stored in a single memory allocation,
** together with Expr.u.zToken strings.
**
** If the EP_Reduced and EP_TokenOnly flags are set when
** an Expr object is truncated.  When EP_Reduced is set, then all
** the child Expr objects in the Expr.pLeft and Expr.pRight subtrees
** are contained within the same memory allocation.  Note, however, that
** the subtrees in Expr.x.pList or Expr.x.pSelect are always separately
** allocated, regardless of whether or not EP_Reduced is set.
*/
struct Expr {
  u8 op;                 /* Operation performed by this node */
  char affExpr;          /* affinity, or RAISE type */
  u8 op2;                /* TK_REGISTER/TK_TRUTH: original value of Expr.op
                         ** TK_COLUMN: the value of p5 for OP_Column
                         ** TK_AGG_FUNCTION: nesting depth
                         ** TK_FUNCTION: NC_SelfRef flag if needs OP_PureFunc */
#ifdef SQLITE_DEBUG
  u8 vvaFlags;           /* Verification flags. */
#endif
  u32 flags;             /* Various flags.  EP_* See below */
  union {
    char *zToken;          /* Token value. Zero terminated and dequoted */
    int iValue;            /* Non-negative integer value if EP_IntValue */
  } u;

  /* If the EP_TokenOnly flag is set in the Expr.flags mask, then no
  ** space is allocated for the fields below this point. An attempt to
  ** access them will result in a segfault or malfunction.
  *********************************************************************/

  Expr *pLeft;           /* Left subnode */
  Expr *pRight;          /* Right subnode */
  union {
    ExprList *pList;     /* op = IN, EXISTS, SELECT, CASE, FUNCTION, BETWEEN */
    Select *pSelect;     /* EP_xIsSelect and op = IN, EXISTS, SELECT */
  } x;

  /* If the EP_Reduced flag is set in the Expr.flags mask, then no
  ** space is allocated for the fields below this point. An attempt to
  ** access them will result in a segfault or malfunction.
  *********************************************************************/

#if SQLITE_MAX_EXPR_DEPTH>0
  int nHeight;           /* Height of the tree headed by this node */
#endif
  int iTable;            /* TK_COLUMN: cursor number of table holding column
                         ** TK_REGISTER: register number
                         ** TK_TRIGGER: 1 -> new, 0 -> old
                         ** EP_Unlikely:  134217728 times likelihood
                         ** TK_IN: ephemeral table holding RHS
                         ** TK_SELECT_COLUMN: Number of columns on the LHS
                         ** TK_SELECT: 1st register of result vector */
  ynVar iColumn;         /* TK_COLUMN: column index.  -1 for rowid.
                         ** TK_VARIABLE: variable number (always >= 1).
                         ** TK_SELECT_COLUMN: column of the result vector */
  i16 iAgg;              /* Which entry in pAggInfo->aCol[] or ->aFunc[] */
  union {
    int iJoin;             /* If EP_OuterON or EP_InnerON, the right table */
    int iOfst;             /* else: start of token from start of statement */
  } w;
  AggInfo *pAggInfo;     /* Used by TK_AGG_COLUMN and TK_AGG_FUNCTION */
  union {
    Table *pTab;           /* TK_COLUMN: Table containing column. Can be NULL
                           ** for a column of an index on an expression */
    Window *pWin;          /* EP_WinFunc: Window/Filter defn for a function */
    int nReg;              /* TK_NULLS: Number of registers to NULL out */
    struct {               /* TK_IN, TK_SELECT, and TK_EXISTS */
      int iAddr;             /* Subroutine entry address */
      int regReturn;         /* Register used to hold return address */
    } sub;
  } y;
};

/* The following are the meanings of bits in the Expr.flags field.
** Value restrictions:
**
**          EP_Agg == NC_HasAgg == SF_HasAgg
**          EP_Win == NC_HasWin
*/
#define EP_OuterON    0x000001 /* Originates in ON/USING clause of outer join */
#define EP_InnerON    0x000002 /* Originates in ON/USING of an inner join */
#define EP_Distinct   0x000004 /* Aggregate function with DISTINCT keyword */
#define EP_HasFunc    0x000008 /* Contains one or more functions of any kind */
#define EP_Agg        0x000010 /* Contains one or more aggregate functions */
#define EP_FixedCol   0x000020 /* TK_Column with a known fixed value */
#define EP_VarSelect  0x000040 /* pSelect is correlated, not constant */
#define EP_DblQuoted  0x000080 /* token.z was originally in "..." */
#define EP_InfixFunc  0x000100 /* True for an infix function: LIKE, GLOB, etc */
#define EP_Collate    0x000200 /* Tree contains a TK_COLLATE operator */
#define EP_Commuted   0x000400 /* Comparison operator has been commuted */
#define EP_IntValue   0x000800 /* Integer value contained in u.iValue */
#define EP_xIsSelect  0x001000 /* x.pSelect is valid (otherwise x.pList is) */
#define EP_Skip       0x002000 /* Operator does not contribute to affinity */
#define EP_Reduced    0x004000 /* Expr struct EXPR_REDUCEDSIZE bytes only */
#define EP_Win        0x008000 /* Contains window functions */
#define EP_TokenOnly  0x010000 /* Expr struct EXPR_TOKENONLYSIZE bytes only */
#define EP_FullSize   0x020000 /* Expr structure must remain full sized */
#define EP_IfNullRow  0x040000 /* The TK_IF_NULL_ROW opcode */
#define EP_Unlikely   0x080000 /* unlikely() or likelihood() function */
#define EP_ConstFunc  0x100000 /* A SQLITE_FUNC_CONSTANT or _SLOCHNG function */
#define EP_CanBeNull  0x200000 /* Can be null despite NOT NULL constraint */
#define EP_Subquery   0x400000 /* Tree contains a TK_SELECT operator */
#define EP_Leaf       0x800000 /* Expr.pLeft, .pRight, .u.pSelect all NULL */
#define EP_WinFunc   0x1000000 /* TK_FUNCTION with Expr.y.pWin set */
#define EP_Subrtn    0x2000000 /* Uses Expr.y.sub. TK_IN, _SELECT, or _EXISTS */
#define EP_Quoted    0x4000000 /* TK_ID was originally quoted */

sqlite3.c  view on Meta::CPAN

**
** The jointype starts out showing the join type between the current table
** and the next table on the list.  The parser builds the list this way.
** But sqlite3SrcListShiftJoinType() later shifts the jointypes so that each
** jointype expresses the join between the table and the previous table.
**
** In the colUsed field, the high-order bit (bit 63) is set if the table
** contains more than 63 columns and the 64-th or later column is used.
**
** Aggressive use of "union" helps keep the size of the object small.  This
** has been shown to boost performance, in addition to saving memory.
** Access to union elements is gated by the following rules which should
** always be checked, either by an if-statement or by an assert().
**
**    Field              Only access if this is true
**    ---------------    -----------------------------------
**    u1.zIndexedBy      fg.isIndexedBy
**    u1.pFuncArg        fg.isTabFunc
**    u1.nRow            !fg.isTabFunc  && !fg.isIndexedBy
**
**    u2.pIBIndex        fg.isIndexedBy
**    u2.pCteUse         fg.isCte
**
**    u3.pOn             !fg.isUsing
**    u3.pUsing          fg.isUsing
**
**    u4.zDatabase       !fg.fixedSchema && !fg.isSubquery
**    u4.pSchema         fg.fixedSchema
**    u4.pSubq           fg.isSubquery
**
** See also the sqlite3SrcListDelete() routine for assert() statements that
** check invariants on the fields of this object, especially the flags
** inside the fg struct.
*/
struct SrcItem {
  char *zName;      /* Name of the table */
  char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
  Table *pSTab;     /* Table object for zName. Mnemonic: Srcitem-TABle */
  struct {
    u8 jointype;      /* Type of join between this table and the previous */
    unsigned notIndexed :1;    /* True if there is a NOT INDEXED clause */
    unsigned isIndexedBy :1;   /* True if there is an INDEXED BY clause */
    unsigned isSubquery :1;    /* True if this term is a subquery */
    unsigned isTabFunc :1;     /* True if table-valued-function syntax */
    unsigned isCorrelated :1;  /* True if sub-query is correlated */
    unsigned isMaterialized:1; /* This is a materialized view */
    unsigned viaCoroutine :1;  /* Implemented as a co-routine */
    unsigned isRecursive :1;   /* True for recursive reference in WITH */
    unsigned fromDDL :1;       /* Comes from sqlite_schema */
    unsigned isCte :1;         /* This is a CTE */
    unsigned notCte :1;        /* This item may not match a CTE */
    unsigned isUsing :1;       /* u3.pUsing is valid */
    unsigned isOn :1;          /* u3.pOn was once valid and non-NULL */
    unsigned isSynthUsing :1;  /* u3.pUsing is synthesized from NATURAL */
    unsigned isNestedFrom :1;  /* pSelect is a SF_NestedFrom subquery */
    unsigned rowidUsed :1;     /* The ROWID of this table is referenced */
    unsigned fixedSchema :1;   /* Uses u4.pSchema, not u4.zDatabase */
    unsigned hadSchema :1;     /* Had u4.zDatabase before u4.pSchema */
    unsigned fromExists :1;    /* Comes from WHERE EXISTS(...) */
  } fg;
  int iCursor;      /* The VDBE cursor number used to access this table */
  Bitmask colUsed;  /* Bit N set if column N used. Details above for N>62 */
  union {
    char *zIndexedBy;    /* Identifier from "INDEXED BY <zIndex>" clause */
    ExprList *pFuncArg;  /* Arguments to table-valued-function */
    u32 nRow;            /* Number of rows in a VALUES clause */
  } u1;
  union {
    Index *pIBIndex;  /* Index structure corresponding to u1.zIndexedBy */
    CteUse *pCteUse;  /* CTE Usage info when fg.isCte is true */
  } u2;
  union {
    Expr *pOn;        /* fg.isUsing==0 =>  The ON clause of a join */
    IdList *pUsing;   /* fg.isUsing==1 =>  The USING clause of a join */
  } u3;
  union {
    Schema *pSchema;  /* Schema to which this item is fixed */
    char *zDatabase;  /* Name of database holding this table */
    Subquery *pSubq;  /* Description of a subquery */
  } u4;
};

/*
** The OnOrUsing object represents either an ON clause or a USING clause.
** It can never be both at the same time, but it can be neither.
*/
struct OnOrUsing {
  Expr *pOn;         /* The ON clause of a join */
  IdList *pUsing;    /* The USING clause of a join */
};

/*
** This object represents one or more tables that are the source of
** content for an SQL statement.  For example, a single SrcList object
** is used to hold the FROM clause of a SELECT statement.  SrcList also
** represents the target tables for DELETE, INSERT, and UPDATE statements.
**
*/
struct SrcList {
  int nSrc;             /* Number of tables or subqueries in the FROM clause */
  u32 nAlloc;           /* Number of entries allocated in a[] below */
  SrcItem a[FLEXARRAY]; /* One entry for each identifier on the list */
};

/* Size (in bytes) of a SrcList object that can hold as many as N
** SrcItem objects. */
#define SZ_SRCLIST(N) (offsetof(SrcList,a)+(N)*sizeof(SrcItem))

/* Size (in bytes( of a SrcList object that holds 1 SrcItem.  This is a
** special case of SZ_SRCITEM(1) that comes up often. */
#define SZ_SRCLIST_1  (offsetof(SrcList,a)+sizeof(SrcItem))

/*
** Permitted values of the SrcList.a.jointype field
*/
#define JT_INNER     0x01    /* Any kind of inner or cross join */
#define JT_CROSS     0x02    /* Explicit use of the CROSS keyword */
#define JT_NATURAL   0x04    /* True for a "natural" join */
#define JT_LEFT      0x08    /* Left outer join */
#define JT_RIGHT     0x10    /* Right outer join */
#define JT_OUTER     0x20    /* The "OUTER" keyword is present */

sqlite3.c  view on Meta::CPAN

**    NC_OrderAgg  == SF_OrderByReqd  == SQLITE_FUNC_ANYORDER
**    NC_HasWin    == EP_Win
**
*/
#define NC_AllowAgg  0x000001 /* Aggregate functions are allowed here */
#define NC_PartIdx   0x000002 /* True if resolving a partial index WHERE */
#define NC_IsCheck   0x000004 /* True if resolving a CHECK constraint */
#define NC_GenCol    0x000008 /* True for a GENERATED ALWAYS AS clause */
#define NC_HasAgg    0x000010 /* One or more aggregate functions seen */
#define NC_IdxExpr   0x000020 /* True if resolving columns of CREATE INDEX */
#define NC_SelfRef   0x00002e /* Combo: PartIdx, isCheck, GenCol, and IdxExpr */
#define NC_Subquery  0x000040 /* A subquery has been seen */
#define NC_UEList    0x000080 /* True if uNC.pEList is used */
#define NC_UAggInfo  0x000100 /* True if uNC.pAggInfo is used */
#define NC_UUpsert   0x000200 /* True if uNC.pUpsert is used */
#define NC_UBaseReg  0x000400 /* True if uNC.iBaseReg is used */
#define NC_MinMaxAgg 0x001000 /* min/max aggregates seen.  See note above */
/*                   0x002000 // available for reuse */
#define NC_AllowWin  0x004000 /* Window functions are allowed here */
#define NC_HasWin    0x008000 /* One or more window functions seen */
#define NC_IsDDL     0x010000 /* Resolving names in a CREATE statement */
#define NC_InAggFunc 0x020000 /* True if analyzing arguments to an agg func */
#define NC_FromDDL   0x040000 /* SQL text comes from sqlite_schema */
#define NC_NoSelect  0x080000 /* Do not descend into sub-selects */
#define NC_Where     0x100000 /* Processing WHERE clause of a SELECT */
#define NC_OrderAgg 0x8000000 /* Has an aggregate other than count/min/max */

/*
** An instance of the following object describes a single ON CONFLICT
** clause in an upsert.
**
** The pUpsertTarget field is only set if the ON CONFLICT clause includes
** conflict-target clause.  (In "ON CONFLICT(a,b)" the "(a,b)" is the
** conflict-target clause.)  The pUpsertTargetWhere is the optional
** WHERE clause used to identify partial unique indexes.
**
** pUpsertSet is the list of column=expr terms of the UPDATE statement.
** The pUpsertSet field is NULL for a ON CONFLICT DO NOTHING.  The
** pUpsertWhere is the WHERE clause for the UPDATE and is NULL if the
** WHERE clause is omitted.
*/
struct Upsert {
  ExprList *pUpsertTarget;  /* Optional description of conflict target */
  Expr *pUpsertTargetWhere; /* WHERE clause for partial index targets */
  ExprList *pUpsertSet;     /* The SET clause from an ON CONFLICT UPDATE */
  Expr *pUpsertWhere;       /* WHERE clause for the ON CONFLICT UPDATE */
  Upsert *pNextUpsert;      /* Next ON CONFLICT clause in the list */
  u8 isDoUpdate;            /* True for DO UPDATE.  False for DO NOTHING */
  u8 isDup;                 /* True if 2nd or later with same pUpsertIdx */
  /* Above this point is the parse tree for the ON CONFLICT clauses.
  ** The next group of fields stores intermediate data. */
  void *pToFree;            /* Free memory when deleting the Upsert object */
  /* All fields above are owned by the Upsert object and must be freed
  ** when the Upsert is destroyed.  The fields below are used to transfer
  ** information from the INSERT processing down into the UPDATE processing
  ** while generating code.  The fields below are owned by the INSERT
  ** statement and will be freed by INSERT processing. */
  Index *pUpsertIdx;        /* UNIQUE constraint specified by pUpsertTarget */
  SrcList *pUpsertSrc;      /* Table to be updated */
  int regData;              /* First register holding array of VALUES */
  int iDataCur;             /* Index of the data cursor */
  int iIdxCur;              /* Index of the first index cursor */
};

/*
** An instance of the following structure contains all information
** needed to generate code for a single SELECT statement.
**
** See the header comment on the computeLimitRegisters() routine for a
** detailed description of the meaning of the iLimit and iOffset fields.
**
** addrOpenEphm[] entries contain the address of OP_OpenEphemeral opcodes.
** These addresses must be stored so that we can go back and fill in
** the P4_KEYINFO and P2 parameters later.  Neither the KeyInfo nor
** the number of columns in P2 can be computed at the same time
** as the OP_OpenEphm instruction is coded because not
** enough information about the compound query is known at that point.
** The KeyInfo for addrOpenTran[0] and [1] contains collating sequences
** for the result set.  The KeyInfo for addrOpenEphm[2] contains collating
** sequences for the ORDER BY clause.
*/
struct Select {
  u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
  LogEst nSelectRow;     /* Estimated number of result rows */
  u32 selFlags;          /* Various SF_* values */
  int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
  u32 selId;             /* Unique identifier number for this SELECT */
  int addrOpenEphm[2];   /* OP_OpenEphem opcodes related to this select */
  ExprList *pEList;      /* The fields of the result */
  SrcList *pSrc;         /* The FROM clause */
  Expr *pWhere;          /* The WHERE clause */
  ExprList *pGroupBy;    /* The GROUP BY clause */
  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
  Select *pPrior;        /* Prior select in a compound select statement */
  Select *pNext;         /* Next select to the left in a compound */
  Expr *pLimit;          /* LIMIT expression. NULL means not used. */
  With *pWith;           /* WITH clause attached to this select. Or NULL. */
#ifndef SQLITE_OMIT_WINDOWFUNC
  Window *pWin;          /* List of window functions */
  Window *pWinDefn;      /* List of named window definitions */
#endif
};

/*
** Allowed values for Select.selFlags.  The "SF" prefix stands for
** "Select Flag".
**
** Value constraints (all checked via assert())
**     SF_HasAgg      == NC_HasAgg
**     SF_MinMaxAgg   == NC_MinMaxAgg     == SQLITE_FUNC_MINMAX
**     SF_OrderByReqd == NC_OrderAgg      == SQLITE_FUNC_ANYORDER
**     SF_FixedLimit  == WHERE_USE_LIMIT
*/
#define SF_Distinct      0x0000001 /* Output should be DISTINCT */
#define SF_All           0x0000002 /* Includes the ALL keyword */
#define SF_Resolved      0x0000004 /* Identifiers have been resolved */
#define SF_Aggregate     0x0000008 /* Contains agg functions or a GROUP BY */
#define SF_HasAgg        0x0000010 /* Contains aggregate functions */
#define SF_UsesEphemeral 0x0000020 /* Uses the OpenEphemeral opcode */
#define SF_Expanded      0x0000040 /* sqlite3SelectExpand() called on this */
#define SF_HasTypeInfo   0x0000080 /* FROM subqueries have Table metadata */

sqlite3.c  view on Meta::CPAN

#define SF_MinMaxAgg     0x0001000 /* Aggregate containing min() or max() */
#define SF_Recursive     0x0002000 /* The recursive part of a recursive CTE */
#define SF_FixedLimit    0x0004000 /* nSelectRow set by a constant LIMIT */
#define SF_MaybeConvert  0x0008000 /* Need convertCompoundSelectToSubquery() */
#define SF_Converted     0x0010000 /* By convertCompoundSelectToSubquery() */
#define SF_IncludeHidden 0x0020000 /* Include hidden columns in output */
#define SF_ComplexResult 0x0040000 /* Result contains subquery or function */
#define SF_WhereBegin    0x0080000 /* Really a WhereBegin() call.  Debug Only */
#define SF_WinRewrite    0x0100000 /* Window function rewrite accomplished */
#define SF_View          0x0200000 /* SELECT statement is a view */
#define SF_NoopOrderBy   0x0400000 /* ORDER BY is ignored for this query */
#define SF_UFSrcCheck    0x0800000 /* Check pSrc as required by UPDATE...FROM */
#define SF_PushDown      0x1000000 /* Modified by WHERE-clause push-down opt */
#define SF_MultiPart     0x2000000 /* Has multiple incompatible PARTITIONs */
#define SF_CopyCte       0x4000000 /* SELECT statement is a copy of a CTE */
#define SF_OrderByReqd   0x8000000 /* The ORDER BY clause may not be omitted */
#define SF_UpdateFrom   0x10000000 /* Query originates with UPDATE FROM */
#define SF_Correlated   0x20000000 /* True if references the outer context */
#define SF_OnToWhere    0x40000000 /* One or more ON clauses moved to WHERE */

/* True if SrcItem X is a subquery that has SF_NestedFrom */
#define IsNestedFrom(X) \
   ((X)->fg.isSubquery && \
    ((X)->u4.pSubq->pSelect->selFlags&SF_NestedFrom)!=0)

/*
** The results of a SELECT can be distributed in several ways, as defined
** by one of the following macros.  The "SRT" prefix means "SELECT Result
** Type".
**
**     SRT_Union       Store results as a key in a temporary index
**                     identified by pDest->iSDParm.
**
**     SRT_Except      Remove results from the temporary index pDest->iSDParm.
**
**     SRT_Exists      Store a 1 in memory cell pDest->iSDParm if the result
**                     set is not empty.
**
**     SRT_Discard     Throw the results away.  This is used by SELECT
**                     statements within triggers whose only purpose is
**                     the side-effects of functions.
**
**     SRT_Output      Generate a row of output (using the OP_ResultRow
**                     opcode) for each row in the result set.
**
**     SRT_Mem         Only valid if the result is a single column.
**                     Store the first column of the first result row
**                     in register pDest->iSDParm then abandon the rest
**                     of the query.  This destination implies "LIMIT 1".
**
**     SRT_Set         The result must be a single column.  Store each
**                     row of result as the key in table pDest->iSDParm.
**                     Apply the affinity pDest->affSdst before storing
**                     results.  if pDest->iSDParm2 is positive, then it is
**                     a register holding a Bloom filter for the IN operator
**                     that should be populated in addition to the
**                     pDest->iSDParm table.  This SRT is used to
**                     implement "IN (SELECT ...)".
**
**     SRT_EphemTab    Create an temporary table pDest->iSDParm and store
**                     the result there. The cursor is left open after
**                     returning.  This is like SRT_Table except that
**                     this destination uses OP_OpenEphemeral to create
**                     the table first.
**
**     SRT_Coroutine   Generate a co-routine that returns a new row of
**                     results each time it is invoked.  The entry point
**                     of the co-routine is stored in register pDest->iSDParm
**                     and the result row is stored in pDest->nDest registers
**                     starting with pDest->iSdst.
**
**     SRT_Table       Store results in temporary table pDest->iSDParm.
**     SRT_Fifo        This is like SRT_EphemTab except that the table
**                     is assumed to already be open.  SRT_Fifo has
**                     the additional property of being able to ignore
**                     the ORDER BY clause.
**
**     SRT_DistFifo    Store results in a temporary table pDest->iSDParm.
**                     But also use temporary table pDest->iSDParm+1 as
**                     a record of all prior results and ignore any duplicate
**                     rows.  Name means:  "Distinct Fifo".
**
**     SRT_Queue       Store results in priority queue pDest->iSDParm (really
**                     an index).  Append a sequence number so that all entries
**                     are distinct.
**
**     SRT_DistQueue   Store results in priority queue pDest->iSDParm only if
**                     the same record has never been stored before.  The
**                     index at pDest->iSDParm+1 hold all prior stores.
**
**     SRT_Upfrom      Store results in the temporary table already opened by
**                     pDest->iSDParm. If (pDest->iSDParm<0), then the temp
**                     table is an intkey table - in this case the first
**                     column returned by the SELECT is used as the integer
**                     key. If (pDest->iSDParm>0), then the table is an index
**                     table. (pDest->iSDParm) is the number of key columns in
**                     each index record in this case.
*/
#define SRT_Union        1  /* Store result as keys in an index */
#define SRT_Except       2  /* Remove result from a UNION index */
#define SRT_Exists       3  /* Store 1 if the result is not empty */
#define SRT_Discard      4  /* Do not save the results anywhere */
#define SRT_DistFifo     5  /* Like SRT_Fifo, but unique results only */
#define SRT_DistQueue    6  /* Like SRT_Queue, but unique results only */

/* The DISTINCT clause is ignored for all of the above.  Not that
** IgnorableDistinct() implies IgnorableOrderby() */
#define IgnorableDistinct(X) ((X->eDest)<=SRT_DistQueue)

#define SRT_Queue        7  /* Store result in an queue */
#define SRT_Fifo         8  /* Store result as data with an automatic rowid */

/* The ORDER BY clause is ignored for all of the above */
#define IgnorableOrderby(X) ((X->eDest)<=SRT_Fifo)

#define SRT_Output       9  /* Output each row of result */
#define SRT_Mem         10  /* Store result in a memory cell */
#define SRT_Set         11  /* Store results as keys in an index */
#define SRT_EphemTab    12  /* Create transient tab and store like SRT_Table */
#define SRT_Coroutine   13  /* Generate a single row of result */
#define SRT_Table       14  /* Store result as data with an automatic rowid */

sqlite3.c  view on Meta::CPAN

  int regCtr;           /* Memory register holding the rowid counter */
};

/*
** At least one instance of the following structure is created for each
** trigger that may be fired while parsing an INSERT, UPDATE or DELETE
** statement. All such objects are stored in the linked list headed at
** Parse.pTriggerPrg and deleted once statement compilation has been
** completed.
**
** A Vdbe sub-program that implements the body and WHEN clause of trigger
** TriggerPrg.pTrigger, assuming a default ON CONFLICT clause of
** TriggerPrg.orconf, is stored in the TriggerPrg.pProgram variable.
** The Parse.pTriggerPrg list never contains two entries with the same
** values for both pTrigger and orconf.
**
** The TriggerPrg.aColmask[0] variable is set to a mask of old.* columns
** accessed (or set to 0 for triggers fired as a result of INSERT
** statements). Similarly, the TriggerPrg.aColmask[1] variable is set to
** a mask of new.* columns used by the program.
*/
struct TriggerPrg {
  Trigger *pTrigger;      /* Trigger this program was coded from */
  TriggerPrg *pNext;      /* Next entry in Parse.pTriggerPrg list */
  SubProgram *pProgram;   /* Program implementing pTrigger/orconf */
  int orconf;             /* Default ON CONFLICT policy */
  u32 aColmask[2];        /* Masks of old.*, new.* columns accessed */
};

/*
** The yDbMask datatype for the bitmask of all attached databases.
*/
#if SQLITE_MAX_ATTACHED>30
  typedef unsigned char yDbMask[(SQLITE_MAX_ATTACHED+9)/8];
# define DbMaskTest(M,I)    (((M)[(I)/8]&(1<<((I)&7)))!=0)
# define DbMaskZero(M)      memset((M),0,sizeof(M))
# define DbMaskSet(M,I)     (M)[(I)/8]|=(1<<((I)&7))
# define DbMaskAllZero(M)   sqlite3DbMaskAllZero(M)
# define DbMaskNonZero(M)   (sqlite3DbMaskAllZero(M)==0)
#else
  typedef unsigned int yDbMask;
# define DbMaskTest(M,I)    (((M)&(((yDbMask)1)<<(I)))!=0)
# define DbMaskZero(M)      ((M)=0)
# define DbMaskSet(M,I)     ((M)|=(((yDbMask)1)<<(I)))
# define DbMaskAllZero(M)   ((M)==0)
# define DbMaskNonZero(M)   ((M)!=0)
#endif

/*
** For each index X that has as one of its arguments either an expression
** or the name of a virtual generated column, and if X is in scope such that
** the value of the expression can simply be read from the index, then
** there is an instance of this object on the Parse.pIdxExpr list.
**
** During code generation, while generating code to evaluate expressions,
** this list is consulted and if a matching expression is found, the value
** is read from the index rather than being recomputed.
*/
struct IndexedExpr {
  Expr *pExpr;            /* The expression contained in the index */
  int iDataCur;           /* The data cursor associated with the index */
  int iIdxCur;            /* The index cursor */
  int iIdxCol;            /* The index column that contains value of pExpr */
  u8 bMaybeNullRow;       /* True if we need an OP_IfNullRow check */
  u8 aff;                 /* Affinity of the pExpr expression */
  IndexedExpr *pIENext;   /* Next in a list of all indexed expressions */
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
  const char *zIdxName;   /* Name of index, used only for bytecode comments */
#endif
};

/*
** An instance of the ParseCleanup object specifies an operation that
** should be performed after parsing to deallocation resources obtained
** during the parse and which are no longer needed.
*/
struct ParseCleanup {
  ParseCleanup *pNext;               /* Next cleanup task */
  void *pPtr;                        /* Pointer to object to deallocate */
  void (*xCleanup)(sqlite3*,void*);  /* Deallocation routine */
};

/*
** An SQL parser context.  A copy of this structure is passed through
** the parser and down into all the parser action routine in order to
** carry around information that is global to the entire parse.
**
** The structure is divided into two parts.  When the parser and code
** generate call themselves recursively, the first part of the structure
** is constant but the second part is reset at the beginning and end of
** each recursion.
**
** The nTableLock and aTableLock variables are only used if the shared-cache
** feature is enabled (if sqlite3Tsd()->useSharedData is true). They are
** used to store the set of table-locks required by the statement being
** compiled. Function sqlite3TableLock() is used to add entries to the
** list.
*/
struct Parse {
  sqlite3 *db;         /* The main database structure */
  char *zErrMsg;       /* An error message */
  Vdbe *pVdbe;         /* An engine for executing database bytecode */
  int rc;              /* Return code from execution */
  LogEst nQueryLoop;   /* Est number of iterations of a query (10*log2(N)) */
  u8 nested;           /* Number of nested calls to the parser/code generator */
  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
  u8 isMultiWrite;     /* True if statement may modify/insert multiple rows */
  u8 mayAbort;         /* True if statement may throw an ABORT exception */
  u8 hasCompound;      /* Need to invoke convertCompoundSelectToSubquery() */
  u8 disableLookaside; /* Number of times lookaside has been disabled */
  u8 prepFlags;        /* SQLITE_PREPARE_* flags */
  u8 withinRJSubrtn;   /* Nesting level for RIGHT JOIN body subroutines */
  u8 bHasExists;       /* Has a correlated "EXISTS (SELECT ....)" expression */
  u8 mSubrtnSig;       /* mini Bloom filter on available SubrtnSig.selId */
  u8 eTriggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
  u8 bReturning;       /* Coding a RETURNING trigger */
  u8 eOrconf;          /* Default ON CONFLICT policy for trigger steps */
  u8 disableTriggers;  /* True to disable triggers */
#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
  u8 earlyCleanup;     /* OOM inside sqlite3ParserAddCleanup() */
#endif
#ifdef SQLITE_DEBUG
  u8 ifNotExists;      /* Might be true if IF NOT EXISTS.  Assert()s only */
  u8 isCreate;         /* CREATE TABLE, INDEX, or VIEW (but not TRIGGER)
                       ** and ALTER TABLE ADD COLUMN. */
#endif
  bft colNamesSet :1;   /* TRUE after OP_ColumnName has been issued to pVdbe */
  bft bHasWith :1;      /* True if statement contains WITH */
  bft okConstFactor :1; /* OK to factor out constants */
  bft checkSchema :1;   /* Causes schema cookie check after an error */
  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int szOpAlloc;       /* Bytes of memory space allocated for Vdbe.aOp[] */
  int iSelfTab;        /* Table associated with an index on expr, or negative
                       ** of the base register during check-constraint eval */
  int nLabel;          /* The *negative* of the number of labels used */
  int nLabelAlloc;     /* Number of slots in aLabel */
  int *aLabel;         /* Space to hold the labels */
  ExprList *pConstExpr;/* Constant expressions */
  IndexedExpr *pIdxEpr;/* List of expressions used by active indexes */
  IndexedExpr *pIdxPartExpr; /* Exprs constrained by index WHERE clauses */
  yDbMask writeMask;   /* Start a write transaction on these databases */
  yDbMask cookieMask;  /* Bitmask of schema verified databases */
  int nMaxArg;         /* Max args to xUpdate and xFilter vtab methods */
  int nSelect;         /* Number of SELECT stmts. Counter for Select.selId */
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  u32 nProgressSteps;  /* xProgress steps taken during sqlite3_prepare() */
#endif
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nTableLock;        /* Number of locks in aTableLock */
  TableLock *aTableLock; /* Required table locks for shared-cache mode */
#endif
  AutoincInfo *pAinc;  /* Information about AUTOINCREMENT counters */
  Parse *pToplevel;    /* Parse structure for main program (or NULL) */
  Table *pTriggerTab;  /* Table triggers are being coded for */
  TriggerPrg *pTriggerPrg;  /* Linked list of coded triggers */
  ParseCleanup *pCleanup;   /* List of cleanup operations to run after parse */

  /**************************************************************************
  ** Fields above must be initialized to zero.  The fields that follow,
  ** down to the beginning of the recursive section, do not need to be
  ** initialized as they will be set before being used.  The boundary is
  ** determined by offsetof(Parse,aTempReg).
  **************************************************************************/

  int aTempReg[8];        /* Holding area for temporary registers */
  Parse *pOuterParse;     /* Outer Parse object when nested */
  Token sNameToken;       /* Token with unqualified schema object name */
  u32 oldmask;            /* Mask of old.* columns referenced */
  u32 newmask;            /* Mask of new.* columns referenced */
  union {
    struct {  /* These fields available when isCreate is true */
      int addrCrTab;        /* Address of OP_CreateBtree on CREATE TABLE */
      int regRowid;         /* Register holding rowid of CREATE TABLE entry */
      int regRoot;          /* Register holding root page for new objects */
      Token constraintName; /* Name of the constraint currently being parsed */
    } cr;
    struct {  /* These fields available to all other statements */
      Returning *pReturning; /* The RETURNING clause */
    } d;
  } u1;

  /************************************************************************
  ** Above is constant between recursions.  Below is reset before and after
  ** each recursion.  The boundary between these two regions is determined
  ** using offsetof(Parse,sLastToken) so the sLastToken field must be the
  ** first field in the recursive region.
  ************************************************************************/

  Token sLastToken;       /* The last token parsed */
  ynVar nVar;               /* Number of '?' variables seen in the SQL so far */

sqlite3.c  view on Meta::CPAN

#define PARSE_HDR(X)  (((char*)(X))+offsetof(Parse,zErrMsg))
#define PARSE_HDR_SZ (offsetof(Parse,aTempReg)-offsetof(Parse,zErrMsg)) /* Recursive part w/o aColCache*/
#define PARSE_RECURSE_SZ offsetof(Parse,sLastToken)    /* Recursive part */
#define PARSE_TAIL_SZ (sizeof(Parse)-PARSE_RECURSE_SZ) /* Non-recursive part */
#define PARSE_TAIL(X) (((char*)(X))+PARSE_RECURSE_SZ)  /* Pointer to tail */

/*
** Return true if currently inside an sqlite3_declare_vtab() call.
*/
#ifdef SQLITE_OMIT_VIRTUALTABLE
  #define IN_DECLARE_VTAB 0
#else
  #define IN_DECLARE_VTAB (pParse->eParseMode==PARSE_MODE_DECLARE_VTAB)
#endif

#if defined(SQLITE_OMIT_ALTERTABLE)
  #define IN_RENAME_OBJECT 0
#else
  #define IN_RENAME_OBJECT (pParse->eParseMode>=PARSE_MODE_RENAME)
#endif

#if defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_OMIT_ALTERTABLE)
  #define IN_SPECIAL_PARSE 0
#else
  #define IN_SPECIAL_PARSE (pParse->eParseMode!=PARSE_MODE_NORMAL)
#endif

/*
** An instance of the following structure can be declared on a stack and used
** to save the Parse.zAuthContext value so that it can be restored later.
*/
struct AuthContext {
  const char *zAuthContext;   /* Put saved Parse.zAuthContext here */
  Parse *pParse;              /* The Parse structure */
};

/*
** Bitfield flags for P5 value in various opcodes.
**
** Value constraints (enforced via assert()):
**    OPFLAG_LENGTHARG    == SQLITE_FUNC_LENGTH
**    OPFLAG_TYPEOFARG    == SQLITE_FUNC_TYPEOF
**    OPFLAG_BULKCSR      == BTREE_BULKLOAD
**    OPFLAG_SEEKEQ       == BTREE_SEEK_EQ
**    OPFLAG_FORDELETE    == BTREE_FORDELETE
**    OPFLAG_SAVEPOSITION == BTREE_SAVEPOSITION
**    OPFLAG_AUXDELETE    == BTREE_AUXDELETE
*/
#define OPFLAG_NCHANGE       0x01    /* OP_Insert: Set to update db->nChange */
                                     /* Also used in P2 (not P5) of OP_Delete */
#define OPFLAG_NOCHNG        0x01    /* OP_VColumn nochange for UPDATE */
#define OPFLAG_EPHEM         0x01    /* OP_Column: Ephemeral output is ok */
#define OPFLAG_LASTROWID     0x20    /* Set to update db->lastRowid */
#define OPFLAG_ISUPDATE      0x04    /* This OP_Insert is an sql UPDATE */
#define OPFLAG_APPEND        0x08    /* This is likely to be an append */
#define OPFLAG_USESEEKRESULT 0x10    /* Try to avoid a seek in BtreeInsert() */
#define OPFLAG_ISNOOP        0x40    /* OP_Delete does pre-update-hook only */
#define OPFLAG_LENGTHARG     0x40    /* OP_Column only used for length() */
#define OPFLAG_TYPEOFARG     0x80    /* OP_Column only used for typeof() */
#define OPFLAG_BYTELENARG    0xc0    /* OP_Column only for octet_length() */
#define OPFLAG_BULKCSR       0x01    /* OP_Open** used to open bulk cursor */
#define OPFLAG_SEEKEQ        0x02    /* OP_Open** cursor uses EQ seek only */
#define OPFLAG_FORDELETE     0x08    /* OP_Open should use BTREE_FORDELETE */
#define OPFLAG_P2ISREG       0x10    /* P2 to OP_Open** is a register number */
#define OPFLAG_PERMUTE       0x01    /* OP_Compare: use the permutation */
#define OPFLAG_SAVEPOSITION  0x02    /* OP_Delete/Insert: save cursor pos */
#define OPFLAG_AUXDELETE     0x04    /* OP_Delete: index in a DELETE op */
#define OPFLAG_NOCHNG_MAGIC  0x6d    /* OP_MakeRecord: serialtype 10 is ok */
#define OPFLAG_PREFORMAT     0x80    /* OP_Insert uses preformatted cell */

/*
** Each trigger present in the database schema is stored as an instance of
** struct Trigger.
**
** Pointers to instances of struct Trigger are stored in two ways.
** 1. In the "trigHash" hash table (part of the sqlite3* that represents the
**    database). This allows Trigger structures to be retrieved by name.
** 2. All triggers associated with a single table form a linked list, using the
**    pNext member of struct Trigger. A pointer to the first element of the
**    linked list is stored as the "pTrigger" member of the associated
**    struct Table.
**
** The "step_list" member points to the first element of a linked list
** containing the SQL statements specified as the trigger program.
*/
struct Trigger {
  char *zName;            /* The name of the trigger                        */
  char *table;            /* The table or view to which the trigger applies */
  u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
  u8 tr_tm;               /* One of TRIGGER_BEFORE, TRIGGER_AFTER */
  u8 bReturning;          /* This trigger implements a RETURNING clause */
  Expr *pWhen;            /* The WHEN clause of the expression (may be NULL) */
  IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
                             the <column-list> is stored here */
  Schema *pSchema;        /* Schema containing the trigger */
  Schema *pTabSchema;     /* Schema containing the table */
  TriggerStep *step_list; /* Link list of trigger program steps             */
  Trigger *pNext;         /* Next trigger associated with the table */
};

/*
** A trigger is either a BEFORE or an AFTER trigger.  The following constants
** determine which.
**
** If there are multiple triggers, you might of some BEFORE and some AFTER.
** In that cases, the constants below can be ORed together.
*/
#define TRIGGER_BEFORE  1
#define TRIGGER_AFTER   2

/*
** An instance of struct TriggerStep is used to store a single SQL statement
** that is a part of a trigger-program.
**
** Instances of struct TriggerStep are stored in a singly linked list (linked
** using the "pNext" member) referenced by the "step_list" member of the
** associated struct Trigger instance. The first element of the linked list is
** the first step of the trigger-program.
**
** The "op" member indicates whether this is a "DELETE", "INSERT", "UPDATE" or
** "SELECT" statement. The meanings of the other members is determined by the
** value of "op" as follows:
**
** (op == TK_INSERT)
** orconf    -> stores the ON CONFLICT algorithm
** pSelect   -> The content to be inserted - either a SELECT statement or

sqlite3.c  view on Meta::CPAN

  /* The following callback (if not NULL) is invoked on every VDBE branch
  ** operation.  Set the callback using SQLITE_TESTCTRL_VDBE_COVERAGE.
  */
  void (*xVdbeBranch)(void*,unsigned iSrcLine,u8 eThis,u8 eMx);  /* Callback */
  void *pVdbeBranchArg;                                     /* 1st argument */
#endif
#ifndef SQLITE_OMIT_DESERIALIZE
  sqlite3_int64 mxMemdbSize;        /* Default max memdb size */
#endif
#ifndef SQLITE_UNTESTABLE
  int (*xTestCallback)(int);        /* Invoked by sqlite3FaultSim() */
#endif
#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
  u32 mNoVisibleRowid;              /* TF_NoVisibleRowid if the ROWID_IN_VIEW
                                    ** feature is disabled.  0 if rowids can
                                    ** occur in views. */
#endif
  int bLocaltimeFault;              /* True to fail localtime() calls */
  int (*xAltLocaltime)(const void*,void*); /* Alternative localtime() routine */
  int iOnceResetThreshold;          /* When to reset OP_Once counters */
  u32 szSorterRef;                  /* Min size in bytes to use sorter-refs */
  unsigned int iPrngSeed;           /* Alternative fixed seed for the PRNG */
  /* vvvv--- must be last ---vvv */
#ifdef SQLITE_DEBUG
  sqlite3_int64 aTune[SQLITE_NTUNE]; /* Tuning parameters */
#endif
};

/*
** This macro is used inside of assert() statements to indicate that
** the assert is only valid on a well-formed database.  Instead of:
**
**     assert( X );
**
** One writes:
**
**     assert( X || CORRUPT_DB );
**
** CORRUPT_DB is true during normal operation.  CORRUPT_DB does not indicate
** that the database is definitely corrupt, only that it might be corrupt.
** For most test cases, CORRUPT_DB is set to false using a special
** sqlite3_test_control().  This enables assert() statements to prove
** things that are always true for well-formed databases.
*/
#define CORRUPT_DB  (sqlite3Config.neverCorrupt==0)

/*
** Context pointer passed down through the tree-walk.
*/
struct Walker {
  Parse *pParse;                            /* Parser context.  */
  int (*xExprCallback)(Walker*, Expr*);     /* Callback for expressions */
  int (*xSelectCallback)(Walker*,Select*);  /* Callback for SELECTs */
  void (*xSelectCallback2)(Walker*,Select*);/* Second callback for SELECTs */
  int walkerDepth;                          /* Number of subqueries */
  u16 eCode;                                /* A small processing code */
  u16 mWFlags;                              /* Use-dependent flags */
  union {                                   /* Extra data for callback */
    NameContext *pNC;                         /* Naming context */
    int n;                                    /* A counter */
    int iCur;                                 /* A cursor number */
    SrcList *pSrcList;                        /* FROM clause */
    struct CCurHint *pCCurHint;               /* Used by codeCursorHint() */
    struct RefSrcList *pRefSrcList;           /* sqlite3ReferencesSrcList() */
    int *aiCol;                               /* array of column indexes */
    struct IdxCover *pIdxCover;               /* Check for index coverage */
    ExprList *pGroupBy;                       /* GROUP BY clause */
    Select *pSelect;                          /* HAVING to WHERE clause ctx */
    struct WindowRewrite *pRewrite;           /* Window rewrite context */
    struct WhereConst *pConst;                /* WHERE clause constants */
    struct RenameCtx *pRename;                /* RENAME COLUMN context */
    struct Table *pTab;                       /* Table of generated column */
    struct CoveringIndexCheck *pCovIdxCk;     /* Check for covering index */
    SrcItem *pSrcItem;                        /* A single FROM clause item */
    DbFixer *pFix;                            /* See sqlite3FixSelect() */
    Mem *aMem;                                /* See sqlite3BtreeCursorHint() */
    struct CheckOnCtx *pCheckOnCtx;           /* See selectCheckOnClauses() */
  } u;
};

/*
** The following structure contains information used by the sqliteFix...
** routines as they walk the parse tree to make database references
** explicit.
*/
struct DbFixer {
  Parse *pParse;      /* The parsing context.  Error messages written here */
  Walker w;           /* Walker object */
  Schema *pSchema;    /* Fix items to this schema */
  u8 bTemp;           /* True for TEMP schema entries */
  const char *zDb;    /* Make sure all objects are contained in this database */
  const char *zType;  /* Type of the container - used for error messages */
  const Token *pName; /* Name of the container - used for error messages */
};

/* Forward declarations */
SQLITE_PRIVATE int sqlite3WalkExpr(Walker*, Expr*);
SQLITE_PRIVATE int sqlite3WalkExprNN(Walker*, Expr*);
SQLITE_PRIVATE int sqlite3WalkExprList(Walker*, ExprList*);
SQLITE_PRIVATE int sqlite3WalkSelect(Walker*, Select*);
SQLITE_PRIVATE int sqlite3WalkSelectExpr(Walker*, Select*);
SQLITE_PRIVATE int sqlite3WalkSelectFrom(Walker*, Select*);
SQLITE_PRIVATE int sqlite3ExprWalkNoop(Walker*, Expr*);
SQLITE_PRIVATE int sqlite3SelectWalkNoop(Walker*, Select*);
SQLITE_PRIVATE int sqlite3SelectWalkFail(Walker*, Select*);
SQLITE_PRIVATE int sqlite3WalkerDepthIncrease(Walker*,Select*);
SQLITE_PRIVATE void sqlite3WalkerDepthDecrease(Walker*,Select*);
SQLITE_PRIVATE void sqlite3WalkWinDefnDummyCallback(Walker*,Select*);

#ifdef SQLITE_DEBUG
SQLITE_PRIVATE void sqlite3SelectWalkAssert2(Walker*, Select*);
#endif

#ifndef SQLITE_OMIT_CTE
SQLITE_PRIVATE void sqlite3SelectPopWith(Walker*, Select*);
#else
# define sqlite3SelectPopWith 0
#endif

/*
** Return code from the parse-tree walking primitives and their

sqlite3.c  view on Meta::CPAN

  char zName[FLEXARRAY];      /* Name of this client data. MUST BE LAST */
};

/* The size (in bytes) of a DbClientData object that can has a name
** that is N bytes long, including the zero-terminator. */
#define SZ_DBCLIENTDATA(N) (offsetof(DbClientData,zName)+(N))

#ifdef SQLITE_DEBUG
/*
** An instance of the TreeView object is used for printing the content of
** data structures on sqlite3DebugPrintf() using a tree-like view.
*/
struct TreeView {
  int iLevel;             /* Which level of the tree we are on */
  u8  bLine[100];         /* Draw vertical in column i if bLine[i] is true */
};
#endif /* SQLITE_DEBUG */

/*
** This object is used in various ways, most (but not all) related to window
** functions.
**
**   (1) A single instance of this structure is attached to the
**       the Expr.y.pWin field for each window function in an expression tree.
**       This object holds the information contained in the OVER clause,
**       plus additional fields used during code generation.
**
**   (2) All window functions in a single SELECT form a linked-list
**       attached to Select.pWin.  The Window.pFunc and Window.pExpr
**       fields point back to the expression that is the window function.
**
**   (3) The terms of the WINDOW clause of a SELECT are instances of this
**       object on a linked list attached to Select.pWinDefn.
**
**   (4) For an aggregate function with a FILTER clause, an instance
**       of this object is stored in Expr.y.pWin with eFrmType set to
**       TK_FILTER. In this case the only field used is Window.pFilter.
**
** The uses (1) and (2) are really the same Window object that just happens
** to be accessible in two different ways.  Use case (3) are separate objects.
*/
struct Window {
  char *zName;            /* Name of window (may be NULL) */
  char *zBase;            /* Name of base window for chaining (may be NULL) */
  ExprList *pPartition;   /* PARTITION BY clause */
  ExprList *pOrderBy;     /* ORDER BY clause */
  u8 eFrmType;            /* TK_RANGE, TK_GROUPS, TK_ROWS, or 0 */
  u8 eStart;              /* UNBOUNDED, CURRENT, PRECEDING or FOLLOWING */
  u8 eEnd;                /* UNBOUNDED, CURRENT, PRECEDING or FOLLOWING */
  u8 bImplicitFrame;      /* True if frame was implicitly specified */
  u8 eExclude;            /* TK_NO, TK_CURRENT, TK_TIES, TK_GROUP, or 0 */
  Expr *pStart;           /* Expression for "<expr> PRECEDING" */
  Expr *pEnd;             /* Expression for "<expr> FOLLOWING" */
  Window **ppThis;        /* Pointer to this object in Select.pWin list */
  Window *pNextWin;       /* Next window function belonging to this SELECT */
  Expr *pFilter;          /* The FILTER expression */
  FuncDef *pWFunc;        /* The function */
  int iEphCsr;            /* Partition buffer or Peer buffer */
  int regAccum;           /* Accumulator */
  int regResult;          /* Interim result */
  int csrApp;             /* Function cursor (used by min/max) */
  int regApp;             /* Function register (also used by min/max) */
  int regPart;            /* Array of registers for PARTITION BY values */
  Expr *pOwner;           /* Expression object this window is attached to */
  int nBufferCol;         /* Number of columns in buffer table */
  int iArgCol;            /* Offset of first argument for this function */
  int regOne;             /* Register containing constant value 1 */
  int regStartRowid;
  int regEndRowid;
  u8 bExprArgs;           /* Defer evaluation of window function arguments
                          ** due to the SQLITE_SUBTYPE flag */
};

SQLITE_PRIVATE Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow);
SQLITE_PRIVATE void sqlite3MultiValuesEnd(Parse *pParse, Select *pVal);

#ifndef SQLITE_OMIT_WINDOWFUNC
SQLITE_PRIVATE void sqlite3WindowDelete(sqlite3*, Window*);
SQLITE_PRIVATE void sqlite3WindowUnlinkFromSelect(Window*);
SQLITE_PRIVATE void sqlite3WindowListDelete(sqlite3 *db, Window *p);
SQLITE_PRIVATE Window *sqlite3WindowAlloc(Parse*, int, int, Expr*, int , Expr*, u8);
SQLITE_PRIVATE void sqlite3WindowAttach(Parse*, Expr*, Window*);
SQLITE_PRIVATE void sqlite3WindowLink(Select *pSel, Window *pWin);
SQLITE_PRIVATE int sqlite3WindowCompare(const Parse*, const Window*, const Window*, int);
SQLITE_PRIVATE void sqlite3WindowCodeInit(Parse*, Select*);
SQLITE_PRIVATE void sqlite3WindowCodeStep(Parse*, Select*, WhereInfo*, int, int);
SQLITE_PRIVATE int sqlite3WindowRewrite(Parse*, Select*);
SQLITE_PRIVATE void sqlite3WindowUpdate(Parse*, Window*, Window*, FuncDef*);
SQLITE_PRIVATE Window *sqlite3WindowDup(sqlite3 *db, Expr *pOwner, Window *p);
SQLITE_PRIVATE Window *sqlite3WindowListDup(sqlite3 *db, Window *p);
SQLITE_PRIVATE void sqlite3WindowFunctions(void);
SQLITE_PRIVATE void sqlite3WindowChain(Parse*, Window*, Window*);
SQLITE_PRIVATE Window *sqlite3WindowAssemble(Parse*, Window*, ExprList*, ExprList*, Token*);
#else
# define sqlite3WindowDelete(a,b)
# define sqlite3WindowFunctions()
# define sqlite3WindowAttach(a,b,c)
#endif

/*
** Assuming zIn points to the first byte of a UTF-8 character,
** advance zIn to point to the first byte of the next UTF-8 character.
*/
#define SQLITE_SKIP_UTF8(zIn) {                        \
  if( (*(zIn++))>=0xc0 ){                              \
    while( (*zIn & 0xc0)==0x80 ){ zIn++; }             \
  }                                                    \
}

/*
** The SQLITE_*_BKPT macros are substitutes for the error codes with
** the same name but without the _BKPT suffix.  These macros invoke
** routines that report the line-number on which the error originated
** using sqlite3_log().  The routines also provide a convenient place
** to set a debugger breakpoint.
*/
SQLITE_PRIVATE int sqlite3ReportError(int iErr, int lineno, const char *zType);
SQLITE_PRIVATE int sqlite3CorruptError(int);
SQLITE_PRIVATE int sqlite3MisuseError(int);
SQLITE_PRIVATE int sqlite3CantopenError(int);
#define SQLITE_CORRUPT_BKPT sqlite3CorruptError(__LINE__)

sqlite3.c  view on Meta::CPAN

** 2003 September 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the header file for information that is private to the
** VDBE.  This information used to all be at the top of the single
** source code file "vdbe.c".  When that file became too big (over
** 6000 lines long) it was split up into several smaller files and
** this header information was factored out.
*/
#ifndef SQLITE_VDBEINT_H
#define SQLITE_VDBEINT_H

/*
** The maximum number of times that a statement will try to reparse
** itself before giving up and returning SQLITE_SCHEMA.
*/
#ifndef SQLITE_MAX_SCHEMA_RETRY
# define SQLITE_MAX_SCHEMA_RETRY 50
#endif

/*
** VDBE_DISPLAY_P4 is true or false depending on whether or not the
** "explain" P4 display logic is enabled.
*/
#if !defined(SQLITE_OMIT_EXPLAIN) || !defined(NDEBUG) \
     || defined(VDBE_PROFILE) || defined(SQLITE_DEBUG) \
     || defined(SQLITE_ENABLE_BYTECODE_VTAB)
# define VDBE_DISPLAY_P4 1
#else
# define VDBE_DISPLAY_P4 0
#endif

/*
** SQL is translated into a sequence of instructions to be
** executed by a virtual machine.  Each instruction is an instance
** of the following structure.
*/
typedef struct VdbeOp Op;

/*
** Boolean values
*/
typedef unsigned Bool;

/* Opaque type used by code in vdbesort.c */
typedef struct VdbeSorter VdbeSorter;

/* Elements of the linked list at Vdbe.pAuxData */
typedef struct AuxData AuxData;

/* A cache of large TEXT or BLOB values in a VdbeCursor */
typedef struct VdbeTxtBlbCache VdbeTxtBlbCache;

/* Types of VDBE cursors */
#define CURTYPE_BTREE       0
#define CURTYPE_SORTER      1
#define CURTYPE_VTAB        2
#define CURTYPE_PSEUDO      3

/*
** A VdbeCursor is an superclass (a wrapper) for various cursor objects:
**
**      * A b-tree cursor
**          -  In the main database or in an ephemeral database
**          -  On either an index or a table
**      * A sorter
**      * A virtual table
**      * A one-row "pseudotable" stored in a single register
*/
typedef struct VdbeCursor VdbeCursor;
struct VdbeCursor {
  u8 eCurType;            /* One of the CURTYPE_* values above */
  i8 iDb;                 /* Index of cursor database in db->aDb[] */
  u8 nullRow;             /* True if pointing to a row with no data */
  u8 deferredMoveto;      /* A call to sqlite3BtreeMoveto() is needed */
  u8 isTable;             /* True for rowid tables.  False for indexes */
#ifdef SQLITE_DEBUG
  u8 seekOp;              /* Most recent seek operation on this cursor */
  u8 wrFlag;              /* The wrFlag argument to sqlite3BtreeCursor() */
#endif
  Bool isEphemeral:1;     /* True for an ephemeral table */
  Bool useRandomRowid:1;  /* Generate new record numbers semi-randomly */
  Bool isOrdered:1;       /* True if the table is not BTREE_UNORDERED */
  Bool noReuse:1;         /* OpenEphemeral may not reuse this cursor */
  Bool colCache:1;        /* pCache pointer is initialized and non-NULL */
  u16 seekHit;            /* See the OP_SeekHit and OP_IfNoHope opcodes */
  union {                 /* pBtx for isEphermeral.  pAltMap otherwise */
    Btree *pBtx;            /* Separate file holding temporary table */
    u32 *aAltMap;           /* Mapping from table to index column numbers */
  } ub;
  i64 seqCount;           /* Sequence counter */

  /* Cached OP_Column parse information is only valid if cacheStatus matches
  ** Vdbe.cacheCtr.  Vdbe.cacheCtr will never take on the value of
  ** CACHE_STALE (0) and so setting cacheStatus=CACHE_STALE guarantees that
  ** the cache is out of date. */
  u32 cacheStatus;        /* Cache is valid if this matches Vdbe.cacheCtr */
  int seekResult;         /* Result of previous sqlite3BtreeMoveto() or 0
                          ** if there have been no prior seeks on the cursor. */
  /* seekResult does not distinguish between "no seeks have ever occurred
  ** on this cursor" and "the most recent seek was an exact match".
  ** For CURTYPE_PSEUDO, seekResult is the register holding the record */

  /* When a new VdbeCursor is allocated, only the fields above are zeroed.
  ** The fields that follow are uninitialized, and must be individually
  ** initialized prior to first use. */
  VdbeCursor *pAltCursor; /* Associated index cursor from which to read */
  union {
    BtCursor *pCursor;          /* CURTYPE_BTREE or _PSEUDO.  Btree cursor */
    sqlite3_vtab_cursor *pVCur; /* CURTYPE_VTAB.              Vtab cursor */
    VdbeSorter *pSorter;        /* CURTYPE_SORTER.            Sorter object */
  } uc;
  KeyInfo *pKeyInfo;      /* Info about index keys needed by index cursors */
  u32 iHdrOffset;         /* Offset to next unparsed byte of the header */
  Pgno pgnoRoot;          /* Root page of the open btree cursor */
  i16 nField;             /* Number of fields in the header */
  u16 nHdrParsed;         /* Number of header fields parsed so far */
  i64 movetoTarget;       /* Argument to the deferred sqlite3BtreeMoveto() */
  u32 *aOffset;           /* Pointer to aType[nField] */
  const u8 *aRow;         /* Data for the current row, if all on one page */
  u32 payloadSize;        /* Total number of bytes in the record */
  u32 szRow;              /* Byte available in aRow */
#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
  u64 maskUsed;           /* Mask of columns used by this cursor */
#endif
  VdbeTxtBlbCache *pCache; /* Cache of large TEXT or BLOB values */

  /* Space is allocated for aType to hold at least 2*nField+1 entries:
  ** nField slots for aType[] and nField+1 array slots for aOffset[] */
  u32 aType[FLEXARRAY];    /* Type values record decode.  MUST BE LAST */
};

/*
** The size (in bytes) of a VdbeCursor object that has an nField value of N
** or less.  The value of SZ_VDBECURSOR(n) is guaranteed to be a multiple
** of 8.
*/
#define SZ_VDBECURSOR(N) \
    (ROUND8(offsetof(VdbeCursor,aType)) + ((N)+1)*sizeof(u64))

/* Return true if P is a null-only cursor
*/
#define IsNullCursor(P) \
  ((P)->eCurType==CURTYPE_PSEUDO && (P)->nullRow && (P)->seekResult==0)

/*
** A value for VdbeCursor.cacheStatus that means the cache is always invalid.
*/
#define CACHE_STALE 0

/*
** Large TEXT or BLOB values can be slow to load, so we want to avoid
** loading them more than once.  For that reason, large TEXT and BLOB values
** can be stored in a cache defined by this object, and attached to the
** VdbeCursor using the pCache field.
*/
struct VdbeTxtBlbCache {
  char *pCValue;        /* A RCStr buffer to hold the value */
  i64 iOffset;          /* File offset of the row being cached */
  int iCol;             /* Column for which the cache is valid */
  u32 cacheStatus;      /* Vdbe.cacheCtr value */
  u32 colCacheCtr;      /* Column cache counter */
};

/*
** When a sub-program is executed (OP_Program), a structure of this type
** is allocated to store the current value of the program counter, as
** well as the current memory cell array and various other frame specific
** values stored in the Vdbe struct. When the sub-program is finished,
** these values are copied back to the Vdbe from the VdbeFrame structure,
** restoring the state of the VM to as it was before the sub-program
** began executing.
**
** The memory for a VdbeFrame object is allocated and managed by a memory
** cell in the parent (calling) frame. When the memory cell is deleted or
** overwritten, the VdbeFrame object is not freed immediately. Instead, it
** is linked into the Vdbe.pDelFrame list. The contents of the Vdbe.pDelFrame
** list is deleted when the VM is reset in VdbeHalt(). The reason for doing
** this instead of deleting the VdbeFrame immediately is to avoid recursive
** calls to sqlite3VdbeMemRelease() when the memory cells belonging to the
** child frame are released.
**
** The currently executing frame is stored in Vdbe.pFrame. Vdbe.pFrame is
** set to NULL if the currently executing frame is the main program.
*/
typedef struct VdbeFrame VdbeFrame;
struct VdbeFrame {
  Vdbe *v;                /* VM this frame belongs to */
  VdbeFrame *pParent;     /* Parent of this frame, or NULL if parent is main */
  Op *aOp;                /* Program instructions for parent frame */
  Mem *aMem;              /* Array of memory cells for parent frame */
  VdbeCursor **apCsr;     /* Array of Vdbe cursors for parent frame */
  u8 *aOnce;              /* Bitmask used by OP_Once */
  void *token;            /* Copy of SubProgram.token */
  i64 lastRowid;          /* Last insert rowid (sqlite3.lastRowid) */
  AuxData *pAuxData;      /* Linked list of auxdata allocations */
#if SQLITE_DEBUG
  u32 iFrameMagic;        /* magic number for sanity checking */
#endif
  int nCursor;            /* Number of entries in apCsr */
  int pc;                 /* Program Counter in parent (calling) frame */
  int nOp;                /* Size of aOp array */
  int nMem;               /* Number of entries in aMem */
  int nChildMem;          /* Number of memory cells for child frame */
  int nChildCsr;          /* Number of cursors for child frame */
  i64 nChange;            /* Statement changes (Vdbe.nChange)     */
  i64 nDbChange;          /* Value of db->nChange */
};

/* Magic number for sanity checking on VdbeFrame objects */
#define SQLITE_FRAME_MAGIC 0x879fb71e

/*
** Return a pointer to the array of registers allocated for use
** by a VdbeFrame.
*/
#define VdbeFrameMem(p) ((Mem *)&((u8 *)p)[ROUND8(sizeof(VdbeFrame))])

/*
** Internally, the vdbe manipulates nearly all SQL values as Mem
** structures. Each Mem struct may cache multiple representations (string,
** integer etc.) of the same value.
*/
struct sqlite3_value {
  union MemValue {
    double r;           /* Real value used when MEM_Real is set in flags */
    i64 i;              /* Integer value used when MEM_Int is set in flags */
    int nZero;          /* Extra zero bytes when MEM_Zero and MEM_Blob set */
    const char *zPType; /* Pointer type when MEM_Term|MEM_Subtype|MEM_Null */
    FuncDef *pDef;      /* Used only when flags==MEM_Agg */
  } u;
  char *z;            /* String or BLOB value */
  int n;              /* Number of characters in string value, excluding '\0' */
  u16 flags;          /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
  u8  enc;            /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
  u8  eSubtype;       /* Subtype for this value */
  /* ShallowCopy only needs to copy the information above */
  sqlite3 *db;        /* The associated database connection */
  int szMalloc;       /* Size of the zMalloc allocation */
  u32 uTemp;          /* Transient storage for serial_type in OP_MakeRecord */
  char *zMalloc;      /* Space to hold MEM_Str or MEM_Blob if szMalloc>0 */
  void (*xDel)(void*);/* Destructor for Mem.z - only valid if MEM_Dyn */
#ifdef SQLITE_DEBUG
  Mem *pScopyFrom;    /* This Mem is a shallow copy of pScopyFrom */
  u16 mScopyFlags;    /* flags value immediately after the shallow copy */
  u8  bScopy;         /* The pScopyFrom of some other Mem *might* point here */
#endif
};

/*
** Size of struct Mem not including the Mem.zMalloc member or anything that
** follows.
*/
#define MEMCELLSIZE offsetof(Mem,db)

/* One or more of the following flags are set to indicate the
** representations of the value stored in the Mem struct.
**
**  *  MEM_Null                An SQL NULL value
**
**  *  MEM_Null|MEM_Zero       An SQL NULL with the virtual table
**                             UPDATE no-change flag set
**
**  *  MEM_Null|MEM_Term|      An SQL NULL, but also contains a
**        MEM_Subtype          pointer accessible using

sqlite3.c  view on Meta::CPAN

/* The ScanStatus object holds a single value for the
** sqlite3_stmt_scanstatus() interface.
**
** aAddrRange[]:
**   This array is used by ScanStatus elements associated with EQP
**   notes that make an SQLITE_SCANSTAT_NCYCLE value available. It is
**   an array of up to 3 ranges of VM addresses for which the Vdbe.anCycle[]
**   values should be summed to calculate the NCYCLE value. Each pair of
**   integer addresses is a start and end address (both inclusive) for a range
**   instructions. A start value of 0 indicates an empty range.
*/
typedef struct ScanStatus ScanStatus;
struct ScanStatus {
  int addrExplain;                /* OP_Explain for loop */
  int aAddrRange[6];
  int addrLoop;                   /* Address of "loops" counter */
  int addrVisit;                  /* Address of "rows visited" counter */
  int iSelectID;                  /* The "Select-ID" for this loop */
  LogEst nEst;                    /* Estimated output rows per loop */
  char *zName;                    /* Name of table or index */
};

/* The DblquoteStr object holds the text of a double-quoted
** string for a prepared statement.  A linked list of these objects
** is constructed during statement parsing and is held on Vdbe.pDblStr.
** When computing a normalized SQL statement for an SQL statement, that
** list is consulted for each double-quoted identifier to see if the
** identifier should really be a string literal.
*/
typedef struct DblquoteStr DblquoteStr;
struct DblquoteStr {
  DblquoteStr *pNextStr;   /* Next string literal in the list */
  char z[8];               /* Dequoted value for the string */
};

/*
** An instance of the virtual machine.  This structure contains the complete
** state of the virtual machine.
**
** The "sqlite3_stmt" structure pointer that is returned by sqlite3_prepare()
** is really a pointer to an instance of this structure.
*/
struct Vdbe {
  sqlite3 *db;            /* The database connection that owns this statement */
  Vdbe **ppVPrev,*pVNext; /* Linked list of VDBEs with the same Vdbe.db */
  Parse *pParse;          /* Parsing context used to create this Vdbe */
  ynVar nVar;             /* Number of entries in aVar[] */
  int nMem;               /* Number of memory locations currently allocated */
  int nCursor;            /* Number of slots in apCsr[] */
  u32 cacheCtr;           /* VdbeCursor row cache generation counter */
  int pc;                 /* The program counter */
  int rc;                 /* Value to return */
  i64 nChange;            /* Number of db changes made since last reset */
  int iStatement;         /* Statement number (or 0 if has no opened stmt) */
  i64 iCurrentTime;       /* Value of julianday('now') for this statement */
  i64 nFkConstraint;      /* Number of imm. FK constraints this VM */
  i64 nStmtDefCons;       /* Number of def. constraints when stmt started */
  i64 nStmtDefImmCons;    /* Number of def. imm constraints when stmt started */
  Mem *aMem;              /* The memory locations */
  Mem **apArg;            /* Arguments xUpdate and xFilter vtab methods */
  VdbeCursor **apCsr;     /* One element of this array for each open cursor */
  Mem *aVar;              /* Values for the OP_Variable opcode. */

  /* When allocating a new Vdbe object, all of the fields below should be
  ** initialized to zero or NULL */

  Op *aOp;                /* Space to hold the virtual machine's program */
  int nOp;                /* Number of instructions in the program */
  int nOpAlloc;           /* Slots allocated for aOp[] */
  Mem *aColName;          /* Column names to return */
  Mem *pResultRow;        /* Current output row */
  char *zErrMsg;          /* Error message written here */
  VList *pVList;          /* Name of variables */
#ifndef SQLITE_OMIT_TRACE
  i64 startTime;          /* Time when query started - used for profiling */
#endif
#ifdef SQLITE_DEBUG
  int rcApp;              /* errcode set by sqlite3_result_error_code() */
  u32 nWrite;             /* Number of write operations that have occurred */
  int napArg;             /* Size of the apArg[] array */
#endif
  u16 nResColumn;         /* Number of columns in one row of the result set */
  u16 nResAlloc;          /* Column slots allocated to aColName[] */
  u8 errorAction;         /* Recovery action to do in case of an error */
  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
  u8 prepFlags;           /* SQLITE_PREPARE_* flags */
  u8 eVdbeState;          /* On of the VDBE_*_STATE values */
  bft expired:2;          /* 1: recompile VM immediately  2: when convenient */
  bft explain:2;          /* 0: normal, 1: EXPLAIN, 2: EXPLAIN QUERY PLAN */
  bft changeCntOn:1;      /* True to update the change-counter */
  bft usesStmtJournal:1;  /* True if uses a statement journal */
  bft readOnly:1;         /* True for statements that do not write */
  bft bIsReader:1;        /* True for statements that read */
  bft haveEqpOps:1;       /* Bytecode supports EXPLAIN QUERY PLAN */
  yDbMask btreeMask;      /* Bitmask of db->aDb[] entries referenced */
  yDbMask lockMask;       /* Subset of btreeMask that requires a lock */
  u32 aCounter[9];        /* Counters used by sqlite3_stmt_status() */
  char *zSql;             /* Text of the SQL statement that generated this */
#ifdef SQLITE_ENABLE_NORMALIZE
  char *zNormSql;         /* Normalization of the associated SQL statement */
  DblquoteStr *pDblStr;   /* List of double-quoted string literals */
#endif
  void *pFree;            /* Free this when deleting the vdbe */
  VdbeFrame *pFrame;      /* Parent frame */
  VdbeFrame *pDelFrame;   /* List of frame objects to free on VM reset */
  int nFrame;             /* Number of frames in pFrame list */
  u32 expmask;            /* Binding to these vars invalidates VM */
  SubProgram *pProgram;   /* Linked list of all sub-programs used by VM */
  AuxData *pAuxData;      /* Linked list of auxdata allocations */
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
  int nScan;              /* Entries in aScan[] */
  ScanStatus *aScan;      /* Scan definitions for sqlite3_stmt_scanstatus() */
#endif
};

/*
** The following are allowed values for Vdbe.eVdbeState
*/
#define VDBE_INIT_STATE     0   /* Prepared statement under construction */
#define VDBE_READY_STATE    1   /* Ready to run but not yet started */
#define VDBE_RUN_STATE      2   /* Run in progress */

sqlite3.c  view on Meta::CPAN

    /*  35 */ "Sort"             OpHelp(""),
    /*  36 */ "Rewind"           OpHelp(""),
    /*  37 */ "IfEmpty"          OpHelp("if( empty(P1) ) goto P2"),
    /*  38 */ "SorterNext"       OpHelp(""),
    /*  39 */ "Prev"             OpHelp(""),
    /*  40 */ "Next"             OpHelp(""),
    /*  41 */ "IdxLE"            OpHelp("key=r[P3@P4]"),
    /*  42 */ "IdxGT"            OpHelp("key=r[P3@P4]"),
    /*  43 */ "Or"               OpHelp("r[P3]=(r[P1] || r[P2])"),
    /*  44 */ "And"              OpHelp("r[P3]=(r[P1] && r[P2])"),
    /*  45 */ "IdxLT"            OpHelp("key=r[P3@P4]"),
    /*  46 */ "IdxGE"            OpHelp("key=r[P3@P4]"),
    /*  47 */ "RowSetRead"       OpHelp("r[P3]=rowset(P1)"),
    /*  48 */ "RowSetTest"       OpHelp("if r[P3] in rowset(P1) goto P2"),
    /*  49 */ "Program"          OpHelp(""),
    /*  50 */ "FkIfZero"         OpHelp("if fkctr[P1]==0 goto P2"),
    /*  51 */ "IsNull"           OpHelp("if r[P1]==NULL goto P2"),
    /*  52 */ "NotNull"          OpHelp("if r[P1]!=NULL goto P2"),
    /*  53 */ "Ne"               OpHelp("IF r[P3]!=r[P1]"),
    /*  54 */ "Eq"               OpHelp("IF r[P3]==r[P1]"),
    /*  55 */ "Gt"               OpHelp("IF r[P3]>r[P1]"),
    /*  56 */ "Le"               OpHelp("IF r[P3]<=r[P1]"),
    /*  57 */ "Lt"               OpHelp("IF r[P3]<r[P1]"),
    /*  58 */ "Ge"               OpHelp("IF r[P3]>=r[P1]"),
    /*  59 */ "ElseEq"           OpHelp(""),
    /*  60 */ "IfPos"            OpHelp("if r[P1]>0 then r[P1]-=P3, goto P2"),
    /*  61 */ "IfNotZero"        OpHelp("if r[P1]!=0 then r[P1]--, goto P2"),
    /*  62 */ "DecrJumpZero"     OpHelp("if (--r[P1])==0 goto P2"),
    /*  63 */ "IncrVacuum"       OpHelp(""),
    /*  64 */ "VNext"            OpHelp(""),
    /*  65 */ "Filter"           OpHelp("if key(P3@P4) not in filter(P1) goto P2"),
    /*  66 */ "PureFunc"         OpHelp("r[P3]=func(r[P2@NP])"),
    /*  67 */ "Function"         OpHelp("r[P3]=func(r[P2@NP])"),
    /*  68 */ "Return"           OpHelp(""),
    /*  69 */ "EndCoroutine"     OpHelp(""),
    /*  70 */ "HaltIfNull"       OpHelp("if r[P3]=null halt"),
    /*  71 */ "Halt"             OpHelp(""),
    /*  72 */ "Integer"          OpHelp("r[P2]=P1"),
    /*  73 */ "Int64"            OpHelp("r[P2]=P4"),
    /*  74 */ "String"           OpHelp("r[P2]='P4' (len=P1)"),
    /*  75 */ "BeginSubrtn"      OpHelp("r[P2]=NULL"),
    /*  76 */ "Null"             OpHelp("r[P2..P3]=NULL"),
    /*  77 */ "SoftNull"         OpHelp("r[P1]=NULL"),
    /*  78 */ "Blob"             OpHelp("r[P2]=P4 (len=P1)"),
    /*  79 */ "Variable"         OpHelp("r[P2]=parameter(P1)"),
    /*  80 */ "Move"             OpHelp("r[P2@P3]=r[P1@P3]"),
    /*  81 */ "Copy"             OpHelp("r[P2@P3+1]=r[P1@P3+1]"),
    /*  82 */ "SCopy"            OpHelp("r[P2]=r[P1]"),
    /*  83 */ "IntCopy"          OpHelp("r[P2]=r[P1]"),
    /*  84 */ "FkCheck"          OpHelp(""),
    /*  85 */ "ResultRow"        OpHelp("output=r[P1@P2]"),
    /*  86 */ "CollSeq"          OpHelp(""),
    /*  87 */ "AddImm"           OpHelp("r[P1]=r[P1]+P2"),
    /*  88 */ "RealAffinity"     OpHelp(""),
    /*  89 */ "Cast"             OpHelp("affinity(r[P1])"),
    /*  90 */ "Permutation"      OpHelp(""),
    /*  91 */ "Compare"          OpHelp("r[P1@P3] <-> r[P2@P3]"),
    /*  92 */ "IsTrue"           OpHelp("r[P2] = coalesce(r[P1]==TRUE,P3) ^ P4"),
    /*  93 */ "ZeroOrNull"       OpHelp("r[P2] = 0 OR NULL"),
    /*  94 */ "Offset"           OpHelp("r[P3] = sqlite_offset(P1)"),
    /*  95 */ "Column"           OpHelp("r[P3]=PX cursor P1 column P2"),
    /*  96 */ "TypeCheck"        OpHelp("typecheck(r[P1@P2])"),
    /*  97 */ "Affinity"         OpHelp("affinity(r[P1@P2])"),
    /*  98 */ "MakeRecord"       OpHelp("r[P3]=mkrec(r[P1@P2])"),
    /*  99 */ "Count"            OpHelp("r[P2]=count()"),
    /* 100 */ "ReadCookie"       OpHelp(""),
    /* 101 */ "SetCookie"        OpHelp(""),
    /* 102 */ "ReopenIdx"        OpHelp("root=P2 iDb=P3"),
    /* 103 */ "BitAnd"           OpHelp("r[P3]=r[P1]&r[P2]"),
    /* 104 */ "BitOr"            OpHelp("r[P3]=r[P1]|r[P2]"),
    /* 105 */ "ShiftLeft"        OpHelp("r[P3]=r[P2]<<r[P1]"),
    /* 106 */ "ShiftRight"       OpHelp("r[P3]=r[P2]>>r[P1]"),
    /* 107 */ "Add"              OpHelp("r[P3]=r[P1]+r[P2]"),
    /* 108 */ "Subtract"         OpHelp("r[P3]=r[P2]-r[P1]"),
    /* 109 */ "Multiply"         OpHelp("r[P3]=r[P1]*r[P2]"),
    /* 110 */ "Divide"           OpHelp("r[P3]=r[P2]/r[P1]"),
    /* 111 */ "Remainder"        OpHelp("r[P3]=r[P2]%r[P1]"),
    /* 112 */ "Concat"           OpHelp("r[P3]=r[P2]+r[P1]"),
    /* 113 */ "OpenRead"         OpHelp("root=P2 iDb=P3"),
    /* 114 */ "OpenWrite"        OpHelp("root=P2 iDb=P3"),
    /* 115 */ "BitNot"           OpHelp("r[P2]= ~r[P1]"),
    /* 116 */ "OpenDup"          OpHelp(""),
    /* 117 */ "OpenAutoindex"    OpHelp("nColumn=P2"),
    /* 118 */ "String8"          OpHelp("r[P2]='P4'"),
    /* 119 */ "OpenEphemeral"    OpHelp("nColumn=P2"),
    /* 120 */ "SorterOpen"       OpHelp(""),
    /* 121 */ "SequenceTest"     OpHelp("if( cursor[P1].ctr++ ) pc = P2"),
    /* 122 */ "OpenPseudo"       OpHelp("P3 columns in r[P2]"),
    /* 123 */ "Close"            OpHelp(""),
    /* 124 */ "ColumnsUsed"      OpHelp(""),
    /* 125 */ "SeekScan"         OpHelp("Scan-ahead up to P1 rows"),
    /* 126 */ "SeekHit"          OpHelp("set P2<=seekHit<=P3"),
    /* 127 */ "Sequence"         OpHelp("r[P2]=cursor[P1].ctr++"),
    /* 128 */ "NewRowid"         OpHelp("r[P2]=rowid"),
    /* 129 */ "Insert"           OpHelp("intkey=r[P3] data=r[P2]"),
    /* 130 */ "RowCell"          OpHelp(""),
    /* 131 */ "Delete"           OpHelp(""),
    /* 132 */ "ResetCount"       OpHelp(""),
    /* 133 */ "SorterCompare"    OpHelp("if key(P1)!=trim(r[P3],P4) goto P2"),
    /* 134 */ "SorterData"       OpHelp("r[P2]=data"),
    /* 135 */ "RowData"          OpHelp("r[P2]=data"),
    /* 136 */ "Rowid"            OpHelp("r[P2]=PX rowid of P1"),
    /* 137 */ "NullRow"          OpHelp(""),
    /* 138 */ "SeekEnd"          OpHelp(""),
    /* 139 */ "IdxInsert"        OpHelp("key=r[P2]"),
    /* 140 */ "SorterInsert"     OpHelp("key=r[P2]"),
    /* 141 */ "IdxDelete"        OpHelp("key=r[P2@P3]"),
    /* 142 */ "DeferredSeek"     OpHelp("Move P3 to P1.rowid if needed"),
    /* 143 */ "IdxRowid"         OpHelp("r[P2]=rowid"),
    /* 144 */ "FinishSeek"       OpHelp(""),
    /* 145 */ "Destroy"          OpHelp(""),
    /* 146 */ "Clear"            OpHelp(""),
    /* 147 */ "ResetSorter"      OpHelp(""),
    /* 148 */ "CreateBtree"      OpHelp("r[P2]=root iDb=P1 flags=P3"),
    /* 149 */ "SqlExec"          OpHelp(""),
    /* 150 */ "ParseSchema"      OpHelp(""),
    /* 151 */ "LoadAnalysis"     OpHelp(""),
    /* 152 */ "DropTable"        OpHelp(""),
    /* 153 */ "DropIndex"        OpHelp(""),
    /* 154 */ "Real"             OpHelp("r[P2]=P4"),
    /* 155 */ "DropTrigger"      OpHelp(""),
    /* 156 */ "IntegrityCk"      OpHelp(""),
    /* 157 */ "RowSetAdd"        OpHelp("rowset(P1)=r[P2]"),
    /* 158 */ "Param"            OpHelp(""),
    /* 159 */ "FkCounter"        OpHelp("fkctr[P1]+=P2"),
    /* 160 */ "MemMax"           OpHelp("r[P1]=max(r[P1],r[P2])"),
    /* 161 */ "OffsetLimit"      OpHelp("if r[P1]>0 then r[P2]=r[P1]+max(0,r[P3]) else r[P2]=(-1)"),
    /* 162 */ "AggInverse"       OpHelp("accum=r[P3] inverse(r[P2@P5])"),
    /* 163 */ "AggStep"          OpHelp("accum=r[P3] step(r[P2@P5])"),
    /* 164 */ "AggStep1"         OpHelp("accum=r[P3] step(r[P2@P5])"),
    /* 165 */ "AggValue"         OpHelp("r[P3]=value N=P2"),
    /* 166 */ "AggFinal"         OpHelp("accum=r[P1] N=P2"),
    /* 167 */ "Expire"           OpHelp(""),
    /* 168 */ "CursorLock"       OpHelp(""),
    /* 169 */ "CursorUnlock"     OpHelp(""),
    /* 170 */ "TableLock"        OpHelp("iDb=P1 root=P2 write=P3"),
    /* 171 */ "VBegin"           OpHelp(""),
    /* 172 */ "VCreate"          OpHelp(""),
    /* 173 */ "VDestroy"         OpHelp(""),
    /* 174 */ "VOpen"            OpHelp(""),
    /* 175 */ "VCheck"           OpHelp(""),
    /* 176 */ "VInitIn"          OpHelp("r[P2]=ValueList(P1,P3)"),
    /* 177 */ "VColumn"          OpHelp("r[P3]=vcolumn(P2)"),
    /* 178 */ "VRename"          OpHelp(""),
    /* 179 */ "Pagecount"        OpHelp(""),
    /* 180 */ "MaxPgcnt"         OpHelp(""),
    /* 181 */ "ClrSubtype"       OpHelp("r[P1].subtype = 0"),
    /* 182 */ "GetSubtype"       OpHelp("r[P2] = r[P1].subtype"),
    /* 183 */ "SetSubtype"       OpHelp("r[P2].subtype = r[P1]"),
    /* 184 */ "FilterAdd"        OpHelp("filter(P1) += key(P3@P4)"),
    /* 185 */ "Trace"            OpHelp(""),
    /* 186 */ "CursorHint"       OpHelp(""),
    /* 187 */ "ReleaseReg"       OpHelp("release r[P1@P2] mask P3"),

sqlite3.c  view on Meta::CPAN

    if( 0==osSetEndOfFile(h) ){
      rc = SQLITE_IOERR_TRUNCATE;
    }
  }
  return rc;
}

/*
** Determine the size in bytes of the file opened by the handle passed as
** the first argument.
*/
static int winHandleSize(HANDLE h, sqlite3_int64 *pnByte){
  int rc = SQLITE_OK;

#if SQLITE_OS_WINRT
  FILE_STANDARD_INFO info;
  BOOL b;
  b = osGetFileInformationByHandleEx(h, FileStandardInfo, &info, sizeof(info));
  if( b ){
    *pnByte = info.EndOfFile.QuadPart;
  }else{
    rc = SQLITE_IOERR_FSTAT;
  }
#else
  DWORD upperBits = 0;
  DWORD lowerBits = 0;

  assert( pnByte );
  lowerBits = osGetFileSize(h, &upperBits);
  *pnByte = (((sqlite3_int64)upperBits)<<32) + lowerBits;
  if( lowerBits==INVALID_FILE_SIZE && osGetLastError()!=NO_ERROR ){
    rc = SQLITE_IOERR_FSTAT;
  }
#endif

  return rc;
}

/*
** Close the handle passed as the only argument.
*/
static void winHandleClose(HANDLE h){
  if( h!=INVALID_HANDLE_VALUE ){
    osCloseHandle(h);
  }
}
#endif /* #ifndef SQLITE_OMIT_WAL */

/*
** Truncate an open file to a specified size
*/
static int winTruncate(sqlite3_file *id, sqlite3_int64 nByte){
  winFile *pFile = (winFile*)id;  /* File handle object */
  int rc = SQLITE_OK;             /* Return code for this function */
  DWORD lastErrno;
#if SQLITE_MAX_MMAP_SIZE>0
  sqlite3_int64 oldMmapSize;
  if( pFile->nFetchOut>0 ){
    /* File truncation is a no-op if there are outstanding memory mapped
    ** pages.  This is because truncating the file means temporarily unmapping
    ** the file, and that might delete memory out from under existing cursors.
    **
    ** This can result in incremental vacuum not truncating the file,
    ** if there is an active read cursor when the incremental vacuum occurs.
    ** No real harm comes of this - the database file is not corrupted,
    ** though some folks might complain that the file is bigger than it
    ** needs to be.
    **
    ** The only feasible work-around is to defer the truncation until after
    ** all references to memory-mapped content are closed.  That is doable,
    ** but involves adding a few branches in the common write code path which
    ** could slow down normal operations slightly.  Hence, we have decided for
    ** now to simply make transactions a no-op if there are pending reads.  We
    ** can maybe revisit this decision in the future.
    */
    return SQLITE_OK;
  }
#endif

  assert( pFile );
  SimulateIOError(return SQLITE_IOERR_TRUNCATE);
  OSTRACE(("TRUNCATE pid=%lu, pFile=%p, file=%p, size=%lld, lock=%d\n",
           osGetCurrentProcessId(), pFile, pFile->h, nByte, pFile->locktype));

  /* If the user has configured a chunk-size for this file, truncate the
  ** file so that it consists of an integer number of chunks (i.e. the
  ** actual file size after the operation may be larger than the requested
  ** size).
  */
  if( pFile->szChunk>0 ){
    nByte = ((nByte + pFile->szChunk - 1)/pFile->szChunk) * pFile->szChunk;
  }

#if SQLITE_MAX_MMAP_SIZE>0
  if( pFile->pMapRegion ){
    oldMmapSize = pFile->mmapSize;
  }else{
    oldMmapSize = 0;
  }
  winUnmapfile(pFile);
#endif

  /* SetEndOfFile() returns non-zero when successful, or zero when it fails. */
  if( winSeekFile(pFile, nByte) ){
    rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
                     "winTruncate1", pFile->zPath);
  }else if( 0==osSetEndOfFile(pFile->h) &&
            ((lastErrno = osGetLastError())!=ERROR_USER_MAPPED_FILE) ){
    pFile->lastErrno = lastErrno;
    rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
                     "winTruncate2", pFile->zPath);
  }

#if SQLITE_MAX_MMAP_SIZE>0
  if( rc==SQLITE_OK && oldMmapSize>0 ){
    if( oldMmapSize>nByte ){
      winMapfile(pFile, -1);
    }else{
      winMapfile(pFile, oldMmapSize);
    }
  }
#endif

  OSTRACE(("TRUNCATE pid=%lu, pFile=%p, file=%p, rc=%s\n",

sqlite3.c  view on Meta::CPAN

#ifndef SQLITE_FILE_HEADER /* 123456789 123456 */
#  define SQLITE_FILE_HEADER "SQLite format 3"
#endif

/*
** Page type flags.  An ORed combination of these flags appear as the
** first byte of on-disk image of every BTree page.
*/
#define PTF_INTKEY    0x01
#define PTF_ZERODATA  0x02
#define PTF_LEAFDATA  0x04
#define PTF_LEAF      0x08

/*
** An instance of this object stores information about each a single database
** page that has been loaded into memory.  The information in this object
** is derived from the raw on-disk page content.
**
** As each database page is loaded into memory, the pager allocates an
** instance of this object and zeros the first 8 bytes.  (This is the
** "extra" information associated with each page of the pager.)
**
** Access to all fields of this structure is controlled by the mutex
** stored in MemPage.pBt->mutex.
*/
struct MemPage {
  u8 isInit;           /* True if previously initialized. MUST BE FIRST! */
  u8 intKey;           /* True if table b-trees.  False for index b-trees */
  u8 intKeyLeaf;       /* True if the leaf of an intKey table */
  Pgno pgno;           /* Page number for this page */
  /* Only the first 8 bytes (above) are zeroed by pager.c when a new page
  ** is allocated. All fields that follow must be initialized before use */
  u8 leaf;             /* True if a leaf page */
  u8 hdrOffset;        /* 100 for page 1.  0 otherwise */
  u8 childPtrSize;     /* 0 if leaf==1.  4 if leaf==0 */
  u8 max1bytePayload;  /* min(maxLocal,127) */
  u8 nOverflow;        /* Number of overflow cell bodies in aCell[] */
  u16 maxLocal;        /* Copy of BtShared.maxLocal or BtShared.maxLeaf */
  u16 minLocal;        /* Copy of BtShared.minLocal or BtShared.minLeaf */
  u16 cellOffset;      /* Index in aData of first cell pointer */
  int nFree;           /* Number of free bytes on the page. -1 for unknown */
  u16 nCell;           /* Number of cells on this page, local and ovfl */
  u16 maskPage;        /* Mask for page offset */
  u16 aiOvfl[4];       /* Insert the i-th overflow cell before the aiOvfl-th
                       ** non-overflow cell */
  u8 *apOvfl[4];       /* Pointers to the body of overflow cells */
  BtShared *pBt;       /* Pointer to BtShared that this page is part of */
  u8 *aData;           /* Pointer to disk image of the page data */
  u8 *aDataEnd;        /* One byte past the end of the entire page - not just
                       ** the usable space, the entire page.  Used to prevent
                       ** corruption-induced buffer overflow. */
  u8 *aCellIdx;        /* The cell index area */
  u8 *aDataOfst;       /* Same as aData for leaves.  aData+4 for interior */
  DbPage *pDbPage;     /* Pager page handle */
  u16 (*xCellSize)(MemPage*,u8*);             /* cellSizePtr method */
  void (*xParseCell)(MemPage*,u8*,CellInfo*); /* btreeParseCell method */
};

/*
** A linked list of the following structures is stored at BtShared.pLock.
** Locks are added (or upgraded from READ_LOCK to WRITE_LOCK) when a cursor
** is opened on the table with root page BtShared.iTable. Locks are removed
** from this list when a transaction is committed or rolled back, or when
** a btree handle is closed.
*/
struct BtLock {
  Btree *pBtree;        /* Btree handle holding this lock */
  Pgno iTable;          /* Root page of table */
  u8 eLock;             /* READ_LOCK or WRITE_LOCK */
  BtLock *pNext;        /* Next in BtShared.pLock list */
};

/* Candidate values for BtLock.eLock */
#define READ_LOCK     1
#define WRITE_LOCK    2

/* A Btree handle
**
** A database connection contains a pointer to an instance of
** this object for every database file that it has open.  This structure
** is opaque to the database connection.  The database connection cannot
** see the internals of this structure and only deals with pointers to
** this structure.
**
** For some database files, the same underlying database cache might be
** shared between multiple connections.  In that case, each connection
** has it own instance of this object.  But each instance of this object
** points to the same BtShared object.  The database cache and the
** schema associated with the database file are all contained within
** the BtShared object.
**
** All fields in this structure are accessed under sqlite3.mutex.
** The pBt pointer itself may not be changed while there exists cursors
** in the referenced BtShared that point back to this Btree since those
** cursors have to go through this Btree to find their BtShared and
** they often do so without holding sqlite3.mutex.
*/
struct Btree {
  sqlite3 *db;       /* The database connection holding this btree */
  BtShared *pBt;     /* Sharable content of this btree */
  u8 inTrans;        /* TRANS_NONE, TRANS_READ or TRANS_WRITE */
  u8 sharable;       /* True if we can share pBt with another db */
  u8 locked;         /* True if db currently has pBt locked */
  u8 hasIncrblobCur; /* True if there are one or more Incrblob cursors */
  int wantToLock;    /* Number of nested calls to sqlite3BtreeEnter() */
  int nBackup;       /* Number of backup operations reading this btree */
  u32 iBDataVersion; /* Combines with pBt->pPager->iDataVersion */
  Btree *pNext;      /* List of other sharable Btrees from the same db */
  Btree *pPrev;      /* Back pointer of the same list */
#ifdef SQLITE_DEBUG
  u64 nSeek;         /* Calls to sqlite3BtreeMovetoUnpacked() */
#endif
#ifndef SQLITE_OMIT_SHARED_CACHE
  BtLock lock;       /* Object used to lock page 1 */
#endif
};

/*
** Btree.inTrans may take one of the following values.
**
** If the shared-data extension is enabled, there may be multiple users
** of the Btree structure. At most one of these may open a write transaction,
** but any number may have active read transactions.
**
** These values must match SQLITE_TXN_NONE, SQLITE_TXN_READ, and
** SQLITE_TXN_WRITE
*/
#define TRANS_NONE  0
#define TRANS_READ  1
#define TRANS_WRITE 2

#if TRANS_NONE!=SQLITE_TXN_NONE
# error wrong numeric code for no-transaction
#endif
#if TRANS_READ!=SQLITE_TXN_READ
# error wrong numeric code for read-transaction
#endif
#if TRANS_WRITE!=SQLITE_TXN_WRITE
# error wrong numeric code for write-transaction
#endif


/*
** An instance of this object represents a single database file.
**
** A single database file can be in use at the same time by two
** or more database connections.  When two or more connections are
** sharing the same database file, each connection has it own
** private Btree object for the file and each of those Btrees points
** to this one BtShared object.  BtShared.nRef is the number of
** connections currently sharing this database file.
**
** Fields in this structure are accessed under the BtShared.mutex
** mutex, except for nRef and pNext which are accessed under the
** global SQLITE_MUTEX_STATIC_MAIN mutex.  The pPager field
** may not be modified once it is initially set as long as nRef>0.
** The pSchema field may be set once under BtShared.mutex and
** thereafter is unchanged as long as nRef>0.
**
** isPending:
**
**   If a BtShared client fails to obtain a write-lock on a database
**   table (because there exists one or more read-locks on the table),
**   the shared-cache enters 'pending-lock' state and isPending is
**   set to true.
**
**   The shared-cache leaves the 'pending lock' state when either of
**   the following occur:
**
**     1) The current writer (BtShared.pWriter) concludes its transaction, OR
**     2) The number of locks held by other connections drops to zero.
**
**   while in the 'pending-lock' state, no connection may start a new
**   transaction.
**
**   This feature is included to help prevent writer-starvation.
*/
struct BtShared {
  Pager *pPager;        /* The page cache */
  sqlite3 *db;          /* Database connection currently using this Btree */
  BtCursor *pCursor;    /* A list of all open cursors */
  MemPage *pPage1;      /* First page of the database */
  u8 openFlags;         /* Flags to sqlite3BtreeOpen() */
#ifndef SQLITE_OMIT_AUTOVACUUM
  u8 autoVacuum;        /* True if auto-vacuum is enabled */
  u8 incrVacuum;        /* True if incr-vacuum is enabled */
  u8 bDoTruncate;       /* True to truncate db on commit */
#endif
  u8 inTransaction;     /* Transaction state */
  u8 max1bytePayload;   /* Maximum first byte of cell for a 1-byte payload */
  u8 nReserveWanted;    /* Desired number of extra bytes per page */
  u16 btsFlags;         /* Boolean parameters.  See BTS_* macros below */
  u16 maxLocal;         /* Maximum local payload in non-LEAFDATA tables */
  u16 minLocal;         /* Minimum local payload in non-LEAFDATA tables */
  u16 maxLeaf;          /* Maximum local payload in a LEAFDATA table */
  u16 minLeaf;          /* Minimum local payload in a LEAFDATA table */
  u32 pageSize;         /* Total number of bytes on a page */
  u32 usableSize;       /* Number of usable bytes on each page */
  int nTransaction;     /* Number of open transactions (read + write) */
  u32 nPage;            /* Number of pages in the database */
  void *pSchema;        /* Pointer to space allocated by sqlite3BtreeSchema() */
  void (*xFreeSchema)(void*);  /* Destructor for BtShared.pSchema */
  sqlite3_mutex *mutex; /* Non-recursive mutex required to access this object */
  Bitvec *pHasContent;  /* Set of pages moved to free-list this transaction */
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nRef;             /* Number of references to this structure */
  BtShared *pNext;      /* Next on a list of sharable BtShared structs */
  BtLock *pLock;        /* List of locks held on this shared-btree struct */
  Btree *pWriter;       /* Btree with currently open write transaction */
#endif
  u8 *pTmpSpace;        /* Temp space sufficient to hold a single cell */
  int nPreformatSize;   /* Size of last cell written by TransferRow() */
};

/*
** Allowed values for BtShared.btsFlags
*/
#define BTS_READ_ONLY        0x0001   /* Underlying file is readonly */
#define BTS_PAGESIZE_FIXED   0x0002   /* Page size can no longer be changed */
#define BTS_SECURE_DELETE    0x0004   /* PRAGMA secure_delete is enabled */
#define BTS_OVERWRITE        0x0008   /* Overwrite deleted content with zeros */
#define BTS_FAST_SECURE      0x000c   /* Combination of the previous two */
#define BTS_INITIALLY_EMPTY  0x0010   /* Database was empty at trans start */
#define BTS_NO_WAL           0x0020   /* Do not open write-ahead-log files */
#define BTS_EXCLUSIVE        0x0040   /* pWriter has an exclusive lock */
#define BTS_PENDING          0x0080   /* Waiting for read-locks to clear */

/*
** An instance of the following structure is used to hold information
** about a cell.  The parseCellPtr() function fills in this structure
** based on information extract from the raw disk page.
*/
struct CellInfo {
  i64 nKey;      /* The key for INTKEY tables, or nPayload otherwise */
  u8 *pPayload;  /* Pointer to the start of payload */
  u32 nPayload;  /* Bytes of payload */
  u16 nLocal;    /* Amount of payload held locally, not on overflow */
  u16 nSize;     /* Size of the cell content on the main b-tree page */
};

/*
** Maximum depth of an SQLite B-Tree structure. Any B-Tree deeper than
** this will be declared corrupt. This value is calculated based on a
** maximum database size of 2^31 pages a minimum fanout of 2 for a
** root-node and 3 for all other internal nodes.
**
** If a tree that appears to be taller than this is encountered, it is
** assumed that the database is corrupt.
*/
#define BTCURSOR_MAX_DEPTH 20

/*
** Maximum amount of storage local to a database page, regardless of
** page size.
*/
#define BT_MAX_LOCAL  65501  /* 65536 - 35 */

/*
** A cursor is a pointer to a particular entry within a particular
** b-tree within a database file.
**
** The entry is identified by its MemPage and the index in
** MemPage.aCell[] of the entry.
**
** A single database file can be shared by two more database connections,
** but cursors cannot be shared.  Each cursor is associated with a
** particular database connection identified BtCursor.pBtree.db.
**
** Fields in this structure are accessed under the BtShared.mutex
** found at self->pBt->mutex.
**
** skipNext meaning:
** The meaning of skipNext depends on the value of eState:
**
**   eState            Meaning of skipNext
**   VALID             skipNext is meaningless and is ignored
**   INVALID           skipNext is meaningless and is ignored
**   SKIPNEXT          sqlite3BtreeNext() is a no-op if skipNext>0 and
**                     sqlite3BtreePrevious() is no-op if skipNext<0.
**   REQUIRESEEK       restoreCursorPosition() restores the cursor to
**                     eState=SKIPNEXT if skipNext!=0
**   FAULT             skipNext holds the cursor fault error code.
*/
struct BtCursor {
  u8 eState;                /* One of the CURSOR_XXX constants (see below) */
  u8 curFlags;              /* zero or more BTCF_* flags defined below */
  u8 curPagerFlags;         /* Flags to send to sqlite3PagerGet() */
  u8 hints;                 /* As configured by CursorSetHints() */
  int skipNext;    /* Prev() is noop if negative. Next() is noop if positive.
                   ** Error code if eState==CURSOR_FAULT */
  Btree *pBtree;            /* The Btree to which this cursor belongs */
  Pgno *aOverflow;          /* Cache of overflow page locations */
  void *pKey;               /* Saved key that was cursor last known position */
  /* All fields above are zeroed when the cursor is allocated.  See
  ** sqlite3BtreeCursorZero().  Fields that follow must be manually
  ** initialized. */
#define BTCURSOR_FIRST_UNINIT pBt   /* Name of first uninitialized field */
  BtShared *pBt;            /* The BtShared this cursor points to */
  BtCursor *pNext;          /* Forms a linked list of all cursors */
  CellInfo info;            /* A parse of the cell we are pointing at */
  i64 nKey;                 /* Size of pKey, or last integer key */
  Pgno pgnoRoot;            /* The root page of this tree */
  i8 iPage;                 /* Index of current page in apPage */
  u8 curIntKey;             /* Value of apPage[0]->intKey */
  u16 ix;                   /* Current index for apPage[iPage] */
  u16 aiIdx[BTCURSOR_MAX_DEPTH-1];     /* Current index in apPage[i] */
  struct KeyInfo *pKeyInfo;            /* Arg passed to comparison function */
  MemPage *pPage;                        /* Current page */
  MemPage *apPage[BTCURSOR_MAX_DEPTH-1]; /* Stack of parents of current page */
};

/*
** Legal values for BtCursor.curFlags
*/
#define BTCF_WriteFlag    0x01   /* True if a write cursor */
#define BTCF_ValidNKey    0x02   /* True if info.nKey is valid */
#define BTCF_ValidOvfl    0x04   /* True if aOverflow is valid */
#define BTCF_AtLast       0x08   /* Cursor is pointing to the last entry */
#define BTCF_Incrblob     0x10   /* True if an incremental I/O handle */
#define BTCF_Multiple     0x20   /* Maybe another cursor on the same btree */
#define BTCF_Pinned       0x40   /* Cursor is busy and cannot be moved */

/*
** Potential values for BtCursor.eState.
**
** CURSOR_INVALID:
**   Cursor does not point to a valid entry. This can happen (for example)
**   because the table is empty or because BtreeCursorFirst() has not been
**   called.
**
** CURSOR_VALID:
**   Cursor points to a valid entry. getPayload() etc. may be called.
**
** CURSOR_SKIPNEXT:
**   Cursor is valid except that the Cursor.skipNext field is non-zero
**   indicating that the next sqlite3BtreeNext() or sqlite3BtreePrevious()
**   operation should be a no-op.
**
** CURSOR_REQUIRESEEK:
**   The table that this cursor was opened on still exists, but has been
**   modified since the cursor was last used. The cursor position is saved
**   in variables BtCursor.pKey and BtCursor.nKey. When a cursor is in
**   this state, restoreCursorPosition() can be called to attempt to
**   seek the cursor to the saved position.
**
** CURSOR_FAULT:
**   An unrecoverable error (an I/O error or a malloc failure) has occurred
**   on a different connection that shares the BtShared cache with this
**   cursor.  The error has left the cache in an inconsistent state.
**   Do nothing else with this cursor.  Any attempt to use the cursor
**   should return the error code stored in BtCursor.skipNext
*/
#define CURSOR_VALID             0
#define CURSOR_INVALID           1
#define CURSOR_SKIPNEXT          2
#define CURSOR_REQUIRESEEK       3
#define CURSOR_FAULT             4

/*
** The database page the PENDING_BYTE occupies. This page is never used.
*/
#define PENDING_BYTE_PAGE(pBt)  ((Pgno)((PENDING_BYTE/((pBt)->pageSize))+1))

/*
** These macros define the location of the pointer-map entry for a
** database page. The first argument to each is the number of usable
** bytes on each page of the database (often 1024). The second is the
** page number to look up in the pointer map.
**
** PTRMAP_PAGENO returns the database page number of the pointer-map
** page that stores the required pointer. PTRMAP_PTROFFSET returns
** the offset of the requested map entry.
**
** If the pgno argument passed to PTRMAP_PAGENO is a pointer-map page,
** then pgno is returned. So (pgno==PTRMAP_PAGENO(pgsz, pgno)) can be
** used to test if pgno is a pointer-map page. PTRMAP_ISPAGE implements
** this test.
*/
#define PTRMAP_PAGENO(pBt, pgno) ptrmapPageno(pBt, pgno)
#define PTRMAP_PTROFFSET(pgptrmap, pgno) (5*(pgno-pgptrmap-1))
#define PTRMAP_ISPAGE(pBt, pgno) (PTRMAP_PAGENO((pBt),(pgno))==(pgno))

/*
** The pointer map is a lookup table that identifies the parent page for
** each child page in the database file.  The parent page is the page that
** contains a pointer to the child.  Every page in the database contains
** 0 or 1 parent pages.  (In this context 'database page' refers
** to any page that is not part of the pointer map itself.)  Each pointer map
** entry consists of a single byte 'type' and a 4 byte parent page number.
** The PTRMAP_XXX identifiers below are the valid types.
**
** The purpose of the pointer map is to facility moving pages from one
** position in the file to another as part of autovacuum.  When a page
** is moved, the pointer in its parent must be updated to point to the
** new location.  The pointer map is used to locate the parent page quickly.
**
** PTRMAP_ROOTPAGE: The database page is a root-page. The page-number is not
**                  used in this case.
**
** PTRMAP_FREEPAGE: The database page is an unused (free) page. The page-number
**                  is not used in this case.
**
** PTRMAP_OVERFLOW1: The database page is the first page in a list of
**                   overflow pages. The page number identifies the page that
**                   contains the cell with a pointer to this overflow page.
**
** PTRMAP_OVERFLOW2: The database page is the second or later page in a list of
**                   overflow pages. The page-number identifies the previous
**                   page in the overflow page list.
**

sqlite3.c  view on Meta::CPAN

      return 0;
    }
  }
  return 1;
}
#endif /* NDEBUG */

#ifndef NDEBUG
/*
** Return true if the correct mutexes are held for accessing the
** db->aDb[iDb].pSchema structure.  The mutexes required for schema
** access are:
**
**   (1) The mutex on db
**   (2) if iDb!=1, then the mutex on db->aDb[iDb].pBt.
**
** If pSchema is not NULL, then iDb is computed from pSchema and
** db using sqlite3SchemaToIndex().
*/
SQLITE_PRIVATE int sqlite3SchemaMutexHeld(sqlite3 *db, int iDb, Schema *pSchema){
  Btree *p;
  assert( db!=0 );
  if( db->pVfs==0 && db->nDb==0 ) return 1;
  if( pSchema ) iDb = sqlite3SchemaToIndex(db, pSchema);
  assert( iDb>=0 && iDb<db->nDb );
  if( !sqlite3_mutex_held(db->mutex) ) return 0;
  if( iDb==1 ) return 1;
  p = db->aDb[iDb].pBt;
  assert( p!=0 );
  return p->sharable==0 || p->locked==1;
}
#endif /* NDEBUG */

#else /* SQLITE_THREADSAFE>0 above.  SQLITE_THREADSAFE==0 below */
/*
** The following are special cases for mutex enter routines for use
** in single threaded applications that use shared cache.  Except for
** these two routines, all mutex operations are no-ops in that case and
** are null #defines in btree.h.
**
** If shared cache is disabled, then all btree mutex routines, including
** the ones below, are no-ops and are null #defines in btree.h.
*/

SQLITE_PRIVATE void sqlite3BtreeEnter(Btree *p){
  p->pBt->db = p->db;
}
SQLITE_PRIVATE void sqlite3BtreeEnterAll(sqlite3 *db){
  int i;
  for(i=0; i<db->nDb; i++){
    Btree *p = db->aDb[i].pBt;
    if( p ){
      p->pBt->db = p->db;
    }
  }
}
#endif /* if SQLITE_THREADSAFE */

#ifndef SQLITE_OMIT_INCRBLOB
/*
** Enter a mutex on a Btree given a cursor owned by that Btree.
**
** These entry points are used by incremental I/O only. Enter() is required
** any time OMIT_SHARED_CACHE is not defined, regardless of whether or not
** the build is threadsafe. Leave() is only required by threadsafe builds.
*/
SQLITE_PRIVATE void sqlite3BtreeEnterCursor(BtCursor *pCur){
  sqlite3BtreeEnter(pCur->pBtree);
}
# if SQLITE_THREADSAFE
SQLITE_PRIVATE void sqlite3BtreeLeaveCursor(BtCursor *pCur){
  sqlite3BtreeLeave(pCur->pBtree);
}
# endif
#endif /* ifndef SQLITE_OMIT_INCRBLOB */

#endif /* ifndef SQLITE_OMIT_SHARED_CACHE */

/************** End of btmutex.c *********************************************/
/************** Begin file btree.c *******************************************/
/*
** 2004 April 6
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file implements an external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
/* #include "btreeInt.h" */

/*
** The header string that appears at the beginning of every
** SQLite database.
*/
static const char zMagicHeader[] = SQLITE_FILE_HEADER;

/*
** Set this global variable to 1 to enable tracing using the TRACE
** macro.
*/
#if 0
int sqlite3BtreeTrace=1;  /* True to enable tracing */
# define TRACE(X)  if(sqlite3BtreeTrace){printf X;fflush(stdout);}
#else
# define TRACE(X)
#endif

/*
** Extract a 2-byte big-endian integer from an array of unsigned bytes.
** But if the value is zero, make it 65536.
**
** This routine is used to extract the "offset to cell content area" value
** from the header of a btree page.  If the page size is 65536 and the page
** is empty, the offset should be 65536, but the 2-byte value stores zero.

sqlite3.c  view on Meta::CPAN

  */
  if( isIndex && (!pSchema || (pSchema->schemaFlags&DB_SchemaLoaded)==0) ){
    return 1;
  }

  /* Figure out the root-page that the lock should be held on. For table
  ** b-trees, this is just the root page of the b-tree being read or
  ** written. For index b-trees, it is the root page of the associated
  ** table.  */
  if( isIndex ){
    HashElem *p;
    int bSeen = 0;
    for(p=sqliteHashFirst(&pSchema->idxHash); p; p=sqliteHashNext(p)){
      Index *pIdx = (Index *)sqliteHashData(p);
      if( pIdx->tnum==iRoot ){
        if( bSeen ){
          /* Two or more indexes share the same root page.  There must
          ** be imposter tables.  So just return true.  The assert is not
          ** useful in that case. */
          return 1;
        }
        iTab = pIdx->pTable->tnum;
        bSeen = 1;
      }
    }
  }else{
    iTab = iRoot;
  }

  SHARED_LOCK_TRACE(pBtree->pBt,"hasLock",iRoot,eLockType);

  /* Search for the required lock. Either a write-lock on root-page iTab, a
  ** write-lock on the schema table, or (if the client is reading) a
  ** read-lock on iTab will suffice. Return 1 if any of these are found.  */
  for(pLock=pBtree->pBt->pLock; pLock; pLock=pLock->pNext){
    if( pLock->pBtree==pBtree
     && (pLock->iTable==iTab || (pLock->eLock==WRITE_LOCK && pLock->iTable==1))
     && pLock->eLock>=eLockType
    ){
      return 1;
    }
  }

  /* Failed to find the required lock. */
  return 0;
}
#endif /* SQLITE_DEBUG */

#ifdef SQLITE_DEBUG
/*
**** This function may be used as part of assert() statements only. ****
**
** Return true if it would be illegal for pBtree to write into the
** table or index rooted at iRoot because other shared connections are
** simultaneously reading that same table or index.
**
** It is illegal for pBtree to write if some other Btree object that
** shares the same BtShared object is currently reading or writing
** the iRoot table.  Except, if the other Btree object has the
** read-uncommitted flag set, then it is OK for the other object to
** have a read cursor.
**
** For example, before writing to any part of the table or index
** rooted at page iRoot, one should call:
**
**    assert( !hasReadConflicts(pBtree, iRoot) );
*/
static int hasReadConflicts(Btree *pBtree, Pgno iRoot){
  BtCursor *p;
  for(p=pBtree->pBt->pCursor; p; p=p->pNext){
    if( p->pgnoRoot==iRoot
     && p->pBtree!=pBtree
     && 0==(p->pBtree->db->flags & SQLITE_ReadUncommit)
    ){
      return 1;
    }
  }
  return 0;
}
#endif    /* #ifdef SQLITE_DEBUG */

/*
** Query to see if Btree handle p may obtain a lock of type eLock
** (READ_LOCK or WRITE_LOCK) on the table with root-page iTab. Return
** SQLITE_OK if the lock may be obtained (by calling
** setSharedCacheTableLock()), or SQLITE_LOCKED if not.
*/
static int querySharedCacheTableLock(Btree *p, Pgno iTab, u8 eLock){
  BtShared *pBt = p->pBt;
  BtLock *pIter;

  assert( sqlite3BtreeHoldsMutex(p) );
  assert( eLock==READ_LOCK || eLock==WRITE_LOCK );
  assert( p->db!=0 );
  assert( !(p->db->flags&SQLITE_ReadUncommit)||eLock==WRITE_LOCK||iTab==1 );

  /* If requesting a write-lock, then the Btree must have an open write
  ** transaction on this file. And, obviously, for this to be so there
  ** must be an open write transaction on the file itself.
  */
  assert( eLock==READ_LOCK || (p==pBt->pWriter && p->inTrans==TRANS_WRITE) );
  assert( eLock==READ_LOCK || pBt->inTransaction==TRANS_WRITE );

  /* This routine is a no-op if the shared-cache is not enabled */
  if( !p->sharable ){
    return SQLITE_OK;
  }

  /* If some other connection is holding an exclusive lock, the
  ** requested lock may not be obtained.
  */
  if( pBt->pWriter!=p && (pBt->btsFlags & BTS_EXCLUSIVE)!=0 ){
    sqlite3ConnectionBlocked(p->db, pBt->pWriter->db);
    return SQLITE_LOCKED_SHAREDCACHE;
  }

  for(pIter=pBt->pLock; pIter; pIter=pIter->pNext){
    /* The condition (pIter->eLock!=eLock) in the following if(...)
    ** statement is a simplification of:
    **
    **   (eLock==WRITE_LOCK || pIter->eLock==WRITE_LOCK)

sqlite3.c  view on Meta::CPAN

    BtLock *pLock = *ppIter;
    assert( (pBt->btsFlags & BTS_EXCLUSIVE)==0 || pBt->pWriter==pLock->pBtree );
    assert( pLock->pBtree->inTrans>=pLock->eLock );
    if( pLock->pBtree==p ){
      *ppIter = pLock->pNext;
      assert( pLock->iTable!=1 || pLock==&p->lock );
      if( pLock->iTable!=1 ){
        sqlite3_free(pLock);
      }
    }else{
      ppIter = &pLock->pNext;
    }
  }

  assert( (pBt->btsFlags & BTS_PENDING)==0 || pBt->pWriter );
  if( pBt->pWriter==p ){
    pBt->pWriter = 0;
    pBt->btsFlags &= ~(BTS_EXCLUSIVE|BTS_PENDING);
  }else if( pBt->nTransaction==2 ){
    /* This function is called when Btree p is concluding its
    ** transaction. If there currently exists a writer, and p is not
    ** that writer, then the number of locks held by connections other
    ** than the writer must be about to drop to zero. In this case
    ** set the BTS_PENDING flag to 0.
    **
    ** If there is not currently a writer, then BTS_PENDING must
    ** be zero already. So this next line is harmless in that case.
    */
    pBt->btsFlags &= ~BTS_PENDING;
  }
}

/*
** This function changes all write-locks held by Btree p into read-locks.
*/
static void downgradeAllSharedCacheTableLocks(Btree *p){
  BtShared *pBt = p->pBt;

  SHARED_LOCK_TRACE(pBt, "downgradeLocks", 0, 0);

  if( pBt->pWriter==p ){
    BtLock *pLock;
    pBt->pWriter = 0;
    pBt->btsFlags &= ~(BTS_EXCLUSIVE|BTS_PENDING);
    for(pLock=pBt->pLock; pLock; pLock=pLock->pNext){
      assert( pLock->eLock==READ_LOCK || pLock->pBtree==p );
      pLock->eLock = READ_LOCK;
    }
  }
}

#endif /* SQLITE_OMIT_SHARED_CACHE */

static void releasePage(MemPage *pPage);         /* Forward reference */
static void releasePageOne(MemPage *pPage);      /* Forward reference */
static void releasePageNotNull(MemPage *pPage);  /* Forward reference */

/*
***** This routine is used inside of assert() only ****
**
** Verify that the cursor holds the mutex on its BtShared
*/
#ifdef SQLITE_DEBUG
static int cursorHoldsMutex(BtCursor *p){
  return sqlite3_mutex_held(p->pBt->mutex);
}

/* Verify that the cursor and the BtShared agree about what is the current
** database connetion. This is important in shared-cache mode. If the database
** connection pointers get out-of-sync, it is possible for routines like
** btreeInitPage() to reference an stale connection pointer that references a
** a connection that has already closed.  This routine is used inside assert()
** statements only and for the purpose of double-checking that the btree code
** does keep the database connection pointers up-to-date.
*/
static int cursorOwnsBtShared(BtCursor *p){
  assert( cursorHoldsMutex(p) );
  return (p->pBtree->db==p->pBt->db);
}
#endif

/*
** Invalidate the overflow cache of the cursor passed as the first argument.
** on the shared btree structure pBt.
*/
#define invalidateOverflowCache(pCur) (pCur->curFlags &= ~BTCF_ValidOvfl)

/*
** Invalidate the overflow page-list cache for all cursors opened
** on the shared btree structure pBt.
*/
static void invalidateAllOverflowCache(BtShared *pBt){
  BtCursor *p;
  assert( sqlite3_mutex_held(pBt->mutex) );
  for(p=pBt->pCursor; p; p=p->pNext){
    invalidateOverflowCache(p);
  }
}

#ifndef SQLITE_OMIT_INCRBLOB
/*
** This function is called before modifying the contents of a table
** to invalidate any incrblob cursors that are open on the
** row or one of the rows being modified.
**
** If argument isClearTable is true, then the entire contents of the
** table is about to be deleted. In this case invalidate all incrblob
** cursors open on any row within the table with root-page pgnoRoot.
**
** Otherwise, if argument isClearTable is false, then the row with
** rowid iRow is being replaced or deleted. In this case invalidate
** only those incrblob cursors open on that specific row.
*/
static void invalidateIncrblobCursors(
  Btree *pBtree,          /* The database file to check */
  Pgno pgnoRoot,          /* The table that might be changing */
  i64 iRow,               /* The rowid that might be changing */
  int isClearTable        /* True if all rows are being deleted */
){
  BtCursor *p;
  assert( pBtree->hasIncrblobCur );
  assert( sqlite3BtreeHoldsMutex(pBtree) );
  pBtree->hasIncrblobCur = 0;
  for(p=pBtree->pBt->pCursor; p; p=p->pNext){
    if( (p->curFlags & BTCF_Incrblob)!=0 ){
      pBtree->hasIncrblobCur = 1;
      if( p->pgnoRoot==pgnoRoot && (isClearTable || p->info.nKey==iRow) ){
        p->eState = CURSOR_INVALID;
      }
    }
  }
}

#else
  /* Stub function when INCRBLOB is omitted */
  #define invalidateIncrblobCursors(w,x,y,z)
#endif /* SQLITE_OMIT_INCRBLOB */

/*
** Set bit pgno of the BtShared.pHasContent bitvec. This is called
** when a page that previously contained data becomes a free-list leaf
** page.
**
** The BtShared.pHasContent bitvec exists to work around an obscure
** bug caused by the interaction of two useful IO optimizations surrounding
** free-list leaf pages:
**
**   1) When all data is deleted from a page and the page becomes
**      a free-list leaf page, the page is not written to the database
**      (as free-list leaf pages contain no meaningful data). Sometimes
**      such a page is not even journalled (as it will not be modified,
**      why bother journalling it?).
**
**   2) When a free-list leaf page is reused, its content is not read
**      from the database or written to the journal file (why should it
**      be, if it is not at all meaningful?).
**
** By themselves, these optimizations work fine and provide a handy
** performance boost to bulk delete or insert operations. However, if
** a page is moved to the free-list and then reused within the same
** transaction, a problem comes up. If the page is not journalled when
** it is moved to the free-list and it is also not journalled when it
** is extracted from the free-list and reused, then the original data
** may be lost. In the event of a rollback, it may not be possible
** to restore the database to its original configuration.
**
** The solution is the BtShared.pHasContent bitvec. Whenever a page is
** moved to become a free-list leaf page, the corresponding bit is
** set in the bitvec. Whenever a leaf page is extracted from the free-list,
** optimization 2 above is omitted if the corresponding bit is already
** set in BtShared.pHasContent. The contents of the bitvec are cleared
** at the end of every transaction.
*/
static int btreeSetHasContent(BtShared *pBt, Pgno pgno){
  int rc = SQLITE_OK;
  if( !pBt->pHasContent ){
    assert( pgno<=pBt->nPage );
    pBt->pHasContent = sqlite3BitvecCreate(pBt->nPage);
    if( !pBt->pHasContent ){
      rc = SQLITE_NOMEM_BKPT;
    }
  }
  if( rc==SQLITE_OK && pgno<=sqlite3BitvecSize(pBt->pHasContent) ){
    rc = sqlite3BitvecSet(pBt->pHasContent, pgno);
  }
  return rc;
}

/*
** Query the BtShared.pHasContent vector.
**
** This function is called when a free-list leaf page is removed from the
** free-list for reuse. It returns false if it is safe to retrieve the
** page from the pager layer with the 'no-content' flag set. True otherwise.
*/
static int btreeGetHasContent(BtShared *pBt, Pgno pgno){
  Bitvec *p = pBt->pHasContent;
  return p && (pgno>sqlite3BitvecSize(p) || sqlite3BitvecTestNotNull(p, pgno));
}

/*
** Clear (destroy) the BtShared.pHasContent bitvec. This should be
** invoked at the conclusion of each write-transaction.
*/
static void btreeClearHasContent(BtShared *pBt){
  sqlite3BitvecDestroy(pBt->pHasContent);
  pBt->pHasContent = 0;
}

/*
** Release all of the apPage[] pages for a cursor.
*/
static void btreeReleaseAllCursorPages(BtCursor *pCur){
  int i;
  if( pCur->iPage>=0 ){
    for(i=0; i<pCur->iPage; i++){
      releasePageNotNull(pCur->apPage[i]);
    }
    releasePageNotNull(pCur->pPage);
    pCur->iPage = -1;
  }
}

/*
** The cursor passed as the only argument must point to a valid entry
** when this function is called (i.e. have eState==CURSOR_VALID). This
** function saves the current cursor key in variables pCur->nKey and
** pCur->pKey. SQLITE_OK is returned if successful or an SQLite error
** code otherwise.
**
** If the cursor is open on an intkey table, then the integer key
** (the rowid) is stored in pCur->nKey and pCur->pKey is left set to
** NULL. If the cursor is open on a non-intkey table, then pCur->pKey is
** set to point to a malloced buffer pCur->nKey bytes in size containing
** the key.
*/
static int saveCursorKey(BtCursor *pCur){
  int rc = SQLITE_OK;
  assert( CURSOR_VALID==pCur->eState );
  assert( 0==pCur->pKey );
  assert( cursorHoldsMutex(pCur) );

  if( pCur->curIntKey ){
    /* Only the rowid is required for a table btree */
    pCur->nKey = sqlite3BtreeIntegerKey(pCur);
  }else{
    /* For an index btree, save the complete key content. It is possible
    ** that the current key is corrupt. In that case, it is possible that
    ** the sqlite3VdbeRecordUnpack() function may overread the buffer by
    ** up to the size of 1 varint plus 1 8-byte value when the cursor
    ** position is restored. Hence the 17 bytes of padding allocated
    ** below. */
    void *pKey;
    pCur->nKey = sqlite3BtreePayloadSize(pCur);
    pKey = sqlite3Malloc( ((i64)pCur->nKey) + 9 + 8 );
    if( pKey ){
      rc = sqlite3BtreePayload(pCur, 0, (int)pCur->nKey, pKey);
      if( rc==SQLITE_OK ){
        memset(((u8*)pKey)+pCur->nKey, 0, 9+8);
        pCur->pKey = pKey;
      }else{
        sqlite3_free(pKey);
      }
    }else{
      rc = SQLITE_NOMEM_BKPT;
    }
  }
  assert( !pCur->curIntKey || !pCur->pKey );
  return rc;
}

/*
** Save the current cursor position in the variables BtCursor.nKey
** and BtCursor.pKey. The cursor's state is set to CURSOR_REQUIRESEEK.
**
** The caller must ensure that the cursor is valid (has eState==CURSOR_VALID)
** prior to calling this routine.
*/
static int saveCursorPosition(BtCursor *pCur){
  int rc;

  assert( CURSOR_VALID==pCur->eState || CURSOR_SKIPNEXT==pCur->eState );
  assert( 0==pCur->pKey );
  assert( cursorHoldsMutex(pCur) );

  if( pCur->curFlags & BTCF_Pinned ){
    return SQLITE_CONSTRAINT_PINNED;
  }
  if( pCur->eState==CURSOR_SKIPNEXT ){
    pCur->eState = CURSOR_VALID;
  }else{
    pCur->skipNext = 0;
  }

  rc = saveCursorKey(pCur);
  if( rc==SQLITE_OK ){
    btreeReleaseAllCursorPages(pCur);
    pCur->eState = CURSOR_REQUIRESEEK;
  }

  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl|BTCF_AtLast);
  return rc;
}

/* Forward reference */
static int SQLITE_NOINLINE saveCursorsOnList(BtCursor*,Pgno,BtCursor*);

/*
** Save the positions of all cursors (except pExcept) that are open on
** the table with root-page iRoot.  "Saving the cursor position" means that
** the location in the btree is remembered in such a way that it can be
** moved back to the same spot after the btree has been modified.  This
** routine is called just before cursor pExcept is used to modify the
** table, for example in BtreeDelete() or BtreeInsert().
**
** If there are two or more cursors on the same btree, then all such
** cursors should have their BTCF_Multiple flag set.  The btreeCursor()
** routine enforces that rule.  This routine only needs to be called in
** the uncommon case when pExpect has the BTCF_Multiple flag set.
**
** If pExpect!=NULL and if no other cursors are found on the same root-page,
** then the BTCF_Multiple flag on pExpect is cleared, to avoid another
** pointless call to this routine.
**
** Implementation note:  This routine merely checks to see if any cursors
** need to be saved.  It calls out to saveCursorsOnList() in the (unusual)
** event that cursors are in need to being saved.
*/
static int saveAllCursors(BtShared *pBt, Pgno iRoot, BtCursor *pExcept){
  BtCursor *p;
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( pExcept==0 || pExcept->pBt==pBt );
  for(p=pBt->pCursor; p; p=p->pNext){
    if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) ) break;
  }
  if( p ) return saveCursorsOnList(p, iRoot, pExcept);
  if( pExcept ) pExcept->curFlags &= ~BTCF_Multiple;
  return SQLITE_OK;
}

/* This helper routine to saveAllCursors does the actual work of saving
** the cursors if and when a cursor is found that actually requires saving.
** The common case is that no cursors need to be saved, so this routine is
** broken out from its caller to avoid unnecessary stack pointer movement.
*/
static int SQLITE_NOINLINE saveCursorsOnList(
  BtCursor *p,         /* The first cursor that needs saving */
  Pgno iRoot,          /* Only save cursor with this iRoot. Save all if zero */
  BtCursor *pExcept    /* Do not save this cursor */
){
  do{
    if( p!=pExcept && (0==iRoot || p->pgnoRoot==iRoot) ){
      if( p->eState==CURSOR_VALID || p->eState==CURSOR_SKIPNEXT ){
        int rc = saveCursorPosition(p);
        if( SQLITE_OK!=rc ){
          return rc;
        }
      }else{
        testcase( p->iPage>=0 );
        btreeReleaseAllCursorPages(p);
      }
    }
    p = p->pNext;
  }while( p );
  return SQLITE_OK;
}

/*
** Clear the current cursor position.
*/
SQLITE_PRIVATE void sqlite3BtreeClearCursor(BtCursor *pCur){
  assert( cursorHoldsMutex(pCur) );
  sqlite3_free(pCur->pKey);
  pCur->pKey = 0;
  pCur->eState = CURSOR_INVALID;
}

/*
** In this version of BtreeMoveto, pKey is a packed index record
** such as is generated by the OP_MakeRecord opcode.  Unpack the
** record and then call sqlite3BtreeIndexMoveto() to do the work.
*/
static int btreeMoveto(
  BtCursor *pCur,     /* Cursor open on the btree to be searched */
  const void *pKey,   /* Packed key if the btree is an index */
  i64 nKey,           /* Integer key for tables.  Size of pKey for indices */
  int bias,           /* Bias search to the high end */
  int *pRes           /* Write search results here */
){
  int rc;                    /* Status code */
  UnpackedRecord *pIdxKey;   /* Unpacked index key */

  if( pKey ){
    KeyInfo *pKeyInfo = pCur->pKeyInfo;
    assert( nKey==(i64)(int)nKey );
    pIdxKey = sqlite3VdbeAllocUnpackedRecord(pKeyInfo);
    if( pIdxKey==0 ) return SQLITE_NOMEM_BKPT;
    sqlite3VdbeRecordUnpack((int)nKey, pKey, pIdxKey);
    if( pIdxKey->nField==0 || pIdxKey->nField>pKeyInfo->nAllField ){
      rc = SQLITE_CORRUPT_BKPT;
    }else{
      rc = sqlite3BtreeIndexMoveto(pCur, pIdxKey, pRes);
    }
    sqlite3DbFree(pCur->pKeyInfo->db, pIdxKey);
  }else{
    pIdxKey = 0;
    rc = sqlite3BtreeTableMoveto(pCur, nKey, bias, pRes);
  }
  return rc;
}

/*
** Restore the cursor to the position it was in (or as close to as possible)
** when saveCursorPosition() was called. Note that this call deletes the
** saved position info stored by saveCursorPosition(), so there can be
** at most one effective restoreCursorPosition() call after each
** saveCursorPosition().
*/
static int btreeRestoreCursorPosition(BtCursor *pCur){
  int rc;
  int skipNext = 0;
  assert( cursorOwnsBtShared(pCur) );
  assert( pCur->eState>=CURSOR_REQUIRESEEK );
  if( pCur->eState==CURSOR_FAULT ){
    return pCur->skipNext;
  }
  pCur->eState = CURSOR_INVALID;
  if( sqlite3FaultSim(410) ){
    rc = SQLITE_IOERR;
  }else{
    rc = btreeMoveto(pCur, pCur->pKey, pCur->nKey, 0, &skipNext);
  }
  if( rc==SQLITE_OK ){
    sqlite3_free(pCur->pKey);
    pCur->pKey = 0;
    assert( pCur->eState==CURSOR_VALID || pCur->eState==CURSOR_INVALID );
    if( skipNext ) pCur->skipNext = skipNext;
    if( pCur->skipNext && pCur->eState==CURSOR_VALID ){
      pCur->eState = CURSOR_SKIPNEXT;
    }
  }
  return rc;
}

#define restoreCursorPosition(p) \
  (p->eState>=CURSOR_REQUIRESEEK ? \
         btreeRestoreCursorPosition(p) : \
         SQLITE_OK)

/*
** Determine whether or not a cursor has moved from the position where
** it was last placed, or has been invalidated for any other reason.
** Cursors can move when the row they are pointing at is deleted out
** from under them, for example.  Cursor might also move if a btree
** is rebalanced.
**
** Calling this routine with a NULL cursor pointer returns false.
**
** Use the separate sqlite3BtreeCursorRestore() routine to restore a cursor
** back to where it ought to be if this routine returns true.
*/
SQLITE_PRIVATE int sqlite3BtreeCursorHasMoved(BtCursor *pCur){
  assert( EIGHT_BYTE_ALIGNMENT(pCur)
       || pCur==sqlite3BtreeFakeValidCursor() );
  assert( offsetof(BtCursor, eState)==0 );
  assert( sizeof(pCur->eState)==1 );
  return CURSOR_VALID != *(u8*)pCur;
}

/*
** Return a pointer to a fake BtCursor object that will always answer
** false to the sqlite3BtreeCursorHasMoved() routine above.  The fake
** cursor returned must not be used with any other Btree interface.
*/
SQLITE_PRIVATE BtCursor *sqlite3BtreeFakeValidCursor(void){
  static u8 fakeCursor = CURSOR_VALID;
  assert( offsetof(BtCursor, eState)==0 );
  return (BtCursor*)&fakeCursor;
}

/*
** This routine restores a cursor back to its original position after it
** has been moved by some outside activity (such as a btree rebalance or
** a row having been deleted out from under the cursor).
**
** On success, the *pDifferentRow parameter is false if the cursor is left
** pointing at exactly the same row.  *pDifferntRow is the row the cursor
** was pointing to has been deleted, forcing the cursor to point to some
** nearby row.
**
** This routine should only be called for a cursor that just returned
** TRUE from sqlite3BtreeCursorHasMoved().
*/
SQLITE_PRIVATE int sqlite3BtreeCursorRestore(BtCursor *pCur, int *pDifferentRow){
  int rc;

  assert( pCur!=0 );
  assert( pCur->eState!=CURSOR_VALID );
  rc = restoreCursorPosition(pCur);
  if( rc ){
    *pDifferentRow = 1;
    return rc;
  }
  if( pCur->eState!=CURSOR_VALID ){
    *pDifferentRow = 1;
  }else{
    *pDifferentRow = 0;
  }
  return SQLITE_OK;
}

#ifdef SQLITE_ENABLE_CURSOR_HINTS
/*
** Provide hints to the cursor.  The particular hint given (and the type
** and number of the varargs parameters) is determined by the eHintType
** parameter.  See the definitions of the BTREE_HINT_* macros for details.
*/
SQLITE_PRIVATE void sqlite3BtreeCursorHint(BtCursor *pCur, int eHintType, ...){
  /* Used only by system that substitute their own storage engine */
#ifdef SQLITE_DEBUG
  if( ALWAYS(eHintType==BTREE_HINT_RANGE) ){
    va_list ap;
    Expr *pExpr;
    Walker w;
    memset(&w, 0, sizeof(w));
    w.xExprCallback = sqlite3CursorRangeHintExprCheck;
    va_start(ap, eHintType);
    pExpr = va_arg(ap, Expr*);
    w.u.aMem = va_arg(ap, Mem*);
    va_end(ap);
    assert( pExpr!=0 );
    assert( w.u.aMem!=0 );
    sqlite3WalkExpr(&w, pExpr);
  }
#endif /* SQLITE_DEBUG */
}
#endif /* SQLITE_ENABLE_CURSOR_HINTS */


/*
** Provide flag hints to the cursor.
*/
SQLITE_PRIVATE void sqlite3BtreeCursorHintFlags(BtCursor *pCur, unsigned x){
  assert( x==BTREE_SEEK_EQ || x==BTREE_BULKLOAD || x==0 );
  pCur->hints = (u8)x;
}


#ifndef SQLITE_OMIT_AUTOVACUUM
/*
** Given a page number of a regular database page, return the page
** number for the pointer-map page that contains the entry for the
** input page number.
**
** Return 0 (not a valid page) for pgno==1 since there is
** no pointer map associated with page 1.  The integrity_check logic
** requires that ptrmapPageno(*,1)!=1.
*/
static Pgno ptrmapPageno(BtShared *pBt, Pgno pgno){
  int nPagesPerMapPage;
  Pgno iPtrMap, ret;
  assert( sqlite3_mutex_held(pBt->mutex) );
  if( pgno<2 ) return 0;
  nPagesPerMapPage = (pBt->usableSize/5)+1;
  iPtrMap = (pgno-2)/nPagesPerMapPage;
  ret = (iPtrMap*nPagesPerMapPage) + 2;
  if( ret==PENDING_BYTE_PAGE(pBt) ){
    ret++;
  }
  return ret;
}

/*
** Write an entry into the pointer map.
**
** This routine updates the pointer map entry for page number 'key'
** so that it maps to type 'eType' and parent page number 'pgno'.
**
** If *pRC is initially non-zero (non-SQLITE_OK) then this routine is
** a no-op.  If an error occurs, the appropriate error code is written
** into *pRC.
*/
static void ptrmapPut(BtShared *pBt, Pgno key, u8 eType, Pgno parent, int *pRC){
  DbPage *pDbPage;  /* The pointer map page */
  u8 *pPtrmap;      /* The pointer map data */
  Pgno iPtrmap;     /* The pointer map page number */
  int offset;       /* Offset in pointer map page */
  int rc;           /* Return code from subfunctions */

  if( *pRC ) return;

  assert( sqlite3_mutex_held(pBt->mutex) );
  /* The super-journal page number must never be used as a pointer map page */
  assert( 0==PTRMAP_ISPAGE(pBt, PENDING_BYTE_PAGE(pBt)) );

  assert( pBt->autoVacuum );
  if( key==0 ){
    *pRC = SQLITE_CORRUPT_BKPT;
    return;
  }
  iPtrmap = PTRMAP_PAGENO(pBt, key);

sqlite3.c  view on Meta::CPAN

    }
  }
  if( mutexOpen ){
    assert( sqlite3_mutex_held(mutexOpen) );
    sqlite3_mutex_leave(mutexOpen);
  }
  assert( rc!=SQLITE_OK || sqlite3BtreeConnectionCount(*ppBtree)>0 );
  return rc;
}

/*
** Decrement the BtShared.nRef counter.  When it reaches zero,
** remove the BtShared structure from the sharing list.  Return
** true if the BtShared.nRef counter reaches zero and return
** false if it is still positive.
*/
static int removeFromSharingList(BtShared *pBt){
#ifndef SQLITE_OMIT_SHARED_CACHE
  MUTEX_LOGIC( sqlite3_mutex *pMainMtx; )
  BtShared *pList;
  int removed = 0;

  assert( sqlite3_mutex_notheld(pBt->mutex) );
  MUTEX_LOGIC( pMainMtx = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_MAIN); )
  sqlite3_mutex_enter(pMainMtx);
  pBt->nRef--;
  if( pBt->nRef<=0 ){
    if( GLOBAL(BtShared*,sqlite3SharedCacheList)==pBt ){
      GLOBAL(BtShared*,sqlite3SharedCacheList) = pBt->pNext;
    }else{
      pList = GLOBAL(BtShared*,sqlite3SharedCacheList);
      while( ALWAYS(pList) && pList->pNext!=pBt ){
        pList=pList->pNext;
      }
      if( ALWAYS(pList) ){
        pList->pNext = pBt->pNext;
      }
    }
    if( SQLITE_THREADSAFE ){
      sqlite3_mutex_free(pBt->mutex);
    }
    removed = 1;
  }
  sqlite3_mutex_leave(pMainMtx);
  return removed;
#else
  UNUSED_PARAMETER( pBt );
  return 1;
#endif
}

/*
** Make sure pBt->pTmpSpace points to an allocation of
** MX_CELL_SIZE(pBt) bytes with a 4-byte prefix for a left-child
** pointer.
*/
static SQLITE_NOINLINE int allocateTempSpace(BtShared *pBt){
  assert( pBt!=0 );
  assert( pBt->pTmpSpace==0 );
  /* This routine is called only by btreeCursor() when allocating the
  ** first write cursor for the BtShared object */
  assert( pBt->pCursor!=0 && (pBt->pCursor->curFlags & BTCF_WriteFlag)!=0 );
  pBt->pTmpSpace = sqlite3PageMalloc( pBt->pageSize );
  if( pBt->pTmpSpace==0 ){
    BtCursor *pCur = pBt->pCursor;
    pBt->pCursor = pCur->pNext;  /* Unlink the cursor */
    memset(pCur, 0, sizeof(*pCur));
    return SQLITE_NOMEM_BKPT;
  }

  /* One of the uses of pBt->pTmpSpace is to format cells before
  ** inserting them into a leaf page (function fillInCell()). If
  ** a cell is less than 4 bytes in size, it is rounded up to 4 bytes
  ** by the various routines that manipulate binary cells. Which
  ** can mean that fillInCell() only initializes the first 2 or 3
  ** bytes of pTmpSpace, but that the first 4 bytes are copied from
  ** it into a database page. This is not actually a problem, but it
  ** does cause a valgrind error when the 1 or 2 bytes of uninitialized
  ** data is passed to system call write(). So to avoid this error,
  ** zero the first 4 bytes of temp space here.
  **
  ** Also:  Provide four bytes of initialized space before the
  ** beginning of pTmpSpace as an area available to prepend the
  ** left-child pointer to the beginning of a cell.
  */
  memset(pBt->pTmpSpace, 0, 8);
  pBt->pTmpSpace += 4;
  return SQLITE_OK;
}

/*
** Free the pBt->pTmpSpace allocation
*/
static void freeTempSpace(BtShared *pBt){
  if( pBt->pTmpSpace ){
    pBt->pTmpSpace -= 4;
    sqlite3PageFree(pBt->pTmpSpace);
    pBt->pTmpSpace = 0;
  }
}

/*
** Close an open database and invalidate all cursors.
*/
SQLITE_PRIVATE int sqlite3BtreeClose(Btree *p){
  BtShared *pBt = p->pBt;

  /* Close all cursors opened via this handle.  */
  assert( sqlite3_mutex_held(p->db->mutex) );
  sqlite3BtreeEnter(p);

  /* Verify that no other cursors have this Btree open */
#ifdef SQLITE_DEBUG
  {
    BtCursor *pCur = pBt->pCursor;
    while( pCur ){
      BtCursor *pTmp = pCur;
      pCur = pCur->pNext;
      assert( pTmp->pBtree!=p );

    }
  }
#endif

  /* Rollback any active transaction and free the handle structure.
  ** The call to sqlite3BtreeRollback() drops any table-locks held by
  ** this handle.
  */
  sqlite3BtreeRollback(p, SQLITE_OK, 0);
  sqlite3BtreeLeave(p);

  /* If there are still other outstanding references to the shared-btree
  ** structure, return now. The remainder of this procedure cleans
  ** up the shared-btree.
  */
  assert( p->wantToLock==0 && p->locked==0 );
  if( !p->sharable || removeFromSharingList(pBt) ){
    /* The pBt is no longer on the sharing list, so we can access
    ** it without having to hold the mutex.
    **
    ** Clean out and delete the BtShared object.
    */
    assert( !pBt->pCursor );
    sqlite3PagerClose(pBt->pPager, p->db);
    if( pBt->xFreeSchema && pBt->pSchema ){
      pBt->xFreeSchema(pBt->pSchema);
    }
    sqlite3DbFree(0, pBt->pSchema);
    freeTempSpace(pBt);
    sqlite3_free(pBt);
  }

#ifndef SQLITE_OMIT_SHARED_CACHE
  assert( p->wantToLock==0 );
  assert( p->locked==0 );
  if( p->pPrev ) p->pPrev->pNext = p->pNext;
  if( p->pNext ) p->pNext->pPrev = p->pPrev;
#endif

  sqlite3_free(p);
  return SQLITE_OK;
}

/*
** Change the "soft" limit on the number of pages in the cache.
** Unused and unmodified pages will be recycled when the number of
** pages in the cache exceeds this soft limit.  But the size of the
** cache is allowed to grow larger than this limit if it contains
** dirty pages or pages still in active use.
*/
SQLITE_PRIVATE int sqlite3BtreeSetCacheSize(Btree *p, int mxPage){
  BtShared *pBt = p->pBt;

sqlite3.c  view on Meta::CPAN

      return rc;
    }
    if( nPage>nPageFile ){
      if( sqlite3WritableSchema(pBt->db)==0 ){
        rc = SQLITE_CORRUPT_BKPT;
        goto page1_init_failed;
      }else{
        nPage = nPageFile;
      }
    }
    /* EVIDENCE-OF: R-28312-64704 However, the usable size is not allowed to
    ** be less than 480. In other words, if the page size is 512, then the
    ** reserved space size cannot exceed 32. */
    if( usableSize<480 ){
      goto page1_init_failed;
    }
    pBt->btsFlags |= BTS_PAGESIZE_FIXED;
    pBt->pageSize = pageSize;
    pBt->usableSize = usableSize;
#ifndef SQLITE_OMIT_AUTOVACUUM
    pBt->autoVacuum = (get4byte(&page1[36 + 4*4])?1:0);
    pBt->incrVacuum = (get4byte(&page1[36 + 7*4])?1:0);
#endif
  }

  /* maxLocal is the maximum amount of payload to store locally for
  ** a cell.  Make sure it is small enough so that at least minFanout
  ** cells can will fit on one page.  We assume a 10-byte page header.
  ** Besides the payload, the cell must store:
  **     2-byte pointer to the cell
  **     4-byte child pointer
  **     9-byte nKey value
  **     4-byte nData value
  **     4-byte overflow page pointer
  ** So a cell consists of a 2-byte pointer, a header which is as much as
  ** 17 bytes long, 0 to N bytes of payload, and an optional 4 byte overflow
  ** page pointer.
  */
  pBt->maxLocal = (u16)((pBt->usableSize-12)*64/255 - 23);
  pBt->minLocal = (u16)((pBt->usableSize-12)*32/255 - 23);
  pBt->maxLeaf = (u16)(pBt->usableSize - 35);
  pBt->minLeaf = (u16)((pBt->usableSize-12)*32/255 - 23);
  if( pBt->maxLocal>127 ){
    pBt->max1bytePayload = 127;
  }else{
    pBt->max1bytePayload = (u8)pBt->maxLocal;
  }
  assert( pBt->maxLeaf + 23 <= MX_CELL_SIZE(pBt) );
  pBt->pPage1 = pPage1;
  pBt->nPage = nPage;
  return SQLITE_OK;

page1_init_failed:
  releasePageOne(pPage1);
  pBt->pPage1 = 0;
  return rc;
}

#ifndef NDEBUG
/*
** Return the number of cursors open on pBt. This is for use
** in assert() expressions, so it is only compiled if NDEBUG is not
** defined.
**
** Only write cursors are counted if wrOnly is true.  If wrOnly is
** false then all cursors are counted.
**
** For the purposes of this routine, a cursor is any cursor that
** is capable of reading or writing to the database.  Cursors that
** have been tripped into the CURSOR_FAULT state are not counted.
*/
static int countValidCursors(BtShared *pBt, int wrOnly){
  BtCursor *pCur;
  int r = 0;
  for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
    if( (wrOnly==0 || (pCur->curFlags & BTCF_WriteFlag)!=0)
     && pCur->eState!=CURSOR_FAULT ) r++;
  }
  return r;
}
#endif

/*
** If there are no outstanding cursors and we are not in the middle
** of a transaction but there is a read lock on the database, then
** this routine unrefs the first page of the database file which
** has the effect of releasing the read lock.
**
** If there is a transaction in progress, this routine is a no-op.
*/
static void unlockBtreeIfUnused(BtShared *pBt){
  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( countValidCursors(pBt,0)==0 || pBt->inTransaction>TRANS_NONE );
  if( pBt->inTransaction==TRANS_NONE && pBt->pPage1!=0 ){
    MemPage *pPage1 = pBt->pPage1;
    assert( pPage1->aData );
    assert( sqlite3PagerRefcount(pBt->pPager)==1 );
    pBt->pPage1 = 0;
    releasePageOne(pPage1);
  }
}

/*
** If pBt points to an empty file then convert that empty file
** into a new empty database by initializing the first page of
** the database.
*/
static int newDatabase(BtShared *pBt){
  MemPage *pP1;
  unsigned char *data;
  int rc;

  assert( sqlite3_mutex_held(pBt->mutex) );
  if( pBt->nPage>0 ){
    return SQLITE_OK;
  }
  pP1 = pBt->pPage1;
  assert( pP1!=0 );
  data = pP1->aData;
  rc = sqlite3PagerWrite(pP1->pDbPage);
  if( rc ) return rc;
  memcpy(data, zMagicHeader, sizeof(zMagicHeader));
  assert( sizeof(zMagicHeader)==16 );
  data[16] = (u8)((pBt->pageSize>>8)&0xff);
  data[17] = (u8)((pBt->pageSize>>16)&0xff);
  data[18] = 1;
  data[19] = 1;
  assert( pBt->usableSize<=pBt->pageSize && pBt->usableSize+255>=pBt->pageSize);
  data[20] = (u8)(pBt->pageSize - pBt->usableSize);
  data[21] = 64;
  data[22] = 32;
  data[23] = 32;
  memset(&data[24], 0, 100-24);
  zeroPage(pP1, PTF_INTKEY|PTF_LEAF|PTF_LEAFDATA );
  pBt->btsFlags |= BTS_PAGESIZE_FIXED;
#ifndef SQLITE_OMIT_AUTOVACUUM
  assert( pBt->autoVacuum==1 || pBt->autoVacuum==0 );
  assert( pBt->incrVacuum==1 || pBt->incrVacuum==0 );
  put4byte(&data[36 + 4*4], pBt->autoVacuum);
  put4byte(&data[36 + 7*4], pBt->incrVacuum);
#endif
  pBt->nPage = 1;
  data[31] = 1;
  return SQLITE_OK;

sqlite3.c  view on Meta::CPAN

static void btreeEndTransaction(Btree *p){
  BtShared *pBt = p->pBt;
  sqlite3 *db = p->db;
  assert( sqlite3BtreeHoldsMutex(p) );

#ifndef SQLITE_OMIT_AUTOVACUUM
  pBt->bDoTruncate = 0;
#endif
  if( p->inTrans>TRANS_NONE && db->nVdbeRead>1 ){
    /* If there are other active statements that belong to this database
    ** handle, downgrade to a read-only transaction. The other statements
    ** may still be reading from the database.  */
    downgradeAllSharedCacheTableLocks(p);
    p->inTrans = TRANS_READ;
  }else{
    /* If the handle had any kind of transaction open, decrement the
    ** transaction count of the shared btree. If the transaction count
    ** reaches 0, set the shared state to TRANS_NONE. The unlockBtreeIfUnused()
    ** call below will unlock the pager.  */
    if( p->inTrans!=TRANS_NONE ){
      clearAllSharedCacheTableLocks(p);
      pBt->nTransaction--;
      if( 0==pBt->nTransaction ){
        pBt->inTransaction = TRANS_NONE;
      }
    }

    /* Set the current transaction state to TRANS_NONE and unlock the
    ** pager if this call closed the only read or write transaction.  */
    p->inTrans = TRANS_NONE;
    unlockBtreeIfUnused(pBt);
  }

  btreeIntegrity(p);
}

/*
** Commit the transaction currently in progress.
**
** This routine implements the second phase of a 2-phase commit.  The
** sqlite3BtreeCommitPhaseOne() routine does the first phase and should
** be invoked prior to calling this routine.  The sqlite3BtreeCommitPhaseOne()
** routine did all the work of writing information out to disk and flushing the
** contents so that they are written onto the disk platter.  All this
** routine has to do is delete or truncate or zero the header in the
** the rollback journal (which causes the transaction to commit) and
** drop locks.
**
** Normally, if an error occurs while the pager layer is attempting to
** finalize the underlying journal file, this function returns an error and
** the upper layer will attempt a rollback. However, if the second argument
** is non-zero then this b-tree transaction is part of a multi-file
** transaction. In this case, the transaction has already been committed
** (by deleting a super-journal file) and the caller will ignore this
** functions return code. So, even if an error occurs in the pager layer,
** reset the b-tree objects internal state to indicate that the write
** transaction has been closed. This is quite safe, as the pager will have
** transitioned to the error state.
**
** This will release the write lock on the database file.  If there
** are no active cursors, it also releases the read lock.
*/
SQLITE_PRIVATE int sqlite3BtreeCommitPhaseTwo(Btree *p, int bCleanup){

  if( p->inTrans==TRANS_NONE ) return SQLITE_OK;
  sqlite3BtreeEnter(p);
  btreeIntegrity(p);

  /* If the handle has a write-transaction open, commit the shared-btrees
  ** transaction and set the shared state to TRANS_READ.
  */
  if( p->inTrans==TRANS_WRITE ){
    int rc;
    BtShared *pBt = p->pBt;
    assert( pBt->inTransaction==TRANS_WRITE );
    assert( pBt->nTransaction>0 );
    rc = sqlite3PagerCommitPhaseTwo(pBt->pPager);
    if( rc!=SQLITE_OK && bCleanup==0 ){
      sqlite3BtreeLeave(p);
      return rc;
    }
    p->iBDataVersion--;  /* Compensate for pPager->iDataVersion++; */
    pBt->inTransaction = TRANS_READ;
    btreeClearHasContent(pBt);
  }

  btreeEndTransaction(p);
  sqlite3BtreeLeave(p);
  return SQLITE_OK;
}

/*
** Do both phases of a commit.
*/
SQLITE_PRIVATE int sqlite3BtreeCommit(Btree *p){
  int rc;
  sqlite3BtreeEnter(p);
  rc = sqlite3BtreeCommitPhaseOne(p, 0);
  if( rc==SQLITE_OK ){
    rc = sqlite3BtreeCommitPhaseTwo(p, 0);
  }
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** This routine sets the state to CURSOR_FAULT and the error
** code to errCode for every cursor on any BtShared that pBtree
** references.  Or if the writeOnly flag is set to 1, then only
** trip write cursors and leave read cursors unchanged.
**
** Every cursor is a candidate to be tripped, including cursors
** that belong to other database connections that happen to be
** sharing the cache with pBtree.
**
** This routine gets called when a rollback occurs. If the writeOnly
** flag is true, then only write-cursors need be tripped - read-only
** cursors save their current positions so that they may continue
** following the rollback. Or, if writeOnly is false, all cursors are
** tripped. In general, writeOnly is false if the transaction being
** rolled back modified the database schema. In this case b-tree root
** pages may be moved or deleted from the database altogether, making
** it unsafe for read cursors to continue.
**
** If the writeOnly flag is true and an error is encountered while
** saving the current position of a read-only cursor, all cursors,
** including all read-cursors are tripped.
**
** SQLITE_OK is returned if successful, or if an error occurs while
** saving a cursor position, an SQLite error code.
*/
SQLITE_PRIVATE int sqlite3BtreeTripAllCursors(Btree *pBtree, int errCode, int writeOnly){
  BtCursor *p;
  int rc = SQLITE_OK;

  assert( (writeOnly==0 || writeOnly==1) && BTCF_WriteFlag==1 );
  if( pBtree ){
    sqlite3BtreeEnter(pBtree);
    for(p=pBtree->pBt->pCursor; p; p=p->pNext){
      if( writeOnly && (p->curFlags & BTCF_WriteFlag)==0 ){
        if( p->eState==CURSOR_VALID || p->eState==CURSOR_SKIPNEXT ){
          rc = saveCursorPosition(p);
          if( rc!=SQLITE_OK ){
            (void)sqlite3BtreeTripAllCursors(pBtree, rc, 0);
            break;
          }
        }
      }else{
        sqlite3BtreeClearCursor(p);
        p->eState = CURSOR_FAULT;
        p->skipNext = errCode;
      }
      btreeReleaseAllCursorPages(p);
    }
    sqlite3BtreeLeave(pBtree);
  }
  return rc;
}

/*
** Set the pBt->nPage field correctly, according to the current
** state of the database.  Assume pBt->pPage1 is valid.
*/
static void btreeSetNPage(BtShared *pBt, MemPage *pPage1){
  int nPage = get4byte(&pPage1->aData[28]);
  testcase( nPage==0 );
  if( nPage==0 ) sqlite3PagerPagecount(pBt->pPager, &nPage);
  testcase( pBt->nPage!=(u32)nPage );
  pBt->nPage = nPage;
}

/*
** Rollback the transaction in progress.
**
** If tripCode is not SQLITE_OK then cursors will be invalidated (tripped).
** Only write cursors are tripped if writeOnly is true but all cursors are
** tripped if writeOnly is false.  Any attempt to use
** a tripped cursor will result in an error.
**
** This will release the write lock on the database file.  If there
** are no active cursors, it also releases the read lock.
*/
SQLITE_PRIVATE int sqlite3BtreeRollback(Btree *p, int tripCode, int writeOnly){
  int rc;
  BtShared *pBt = p->pBt;
  MemPage *pPage1;

  assert( writeOnly==1 || writeOnly==0 );
  assert( tripCode==SQLITE_ABORT_ROLLBACK || tripCode==SQLITE_OK );
  sqlite3BtreeEnter(p);
  if( tripCode==SQLITE_OK ){
    rc = tripCode = saveAllCursors(pBt, 0, 0);
    if( rc ) writeOnly = 0;
  }else{
    rc = SQLITE_OK;
  }
  if( tripCode ){
    int rc2 = sqlite3BtreeTripAllCursors(p, tripCode, writeOnly);
    assert( rc==SQLITE_OK || (writeOnly==0 && rc2==SQLITE_OK) );
    if( rc2!=SQLITE_OK ) rc = rc2;
  }
  btreeIntegrity(p);

  if( p->inTrans==TRANS_WRITE ){
    int rc2;

    assert( TRANS_WRITE==pBt->inTransaction );
    rc2 = sqlite3PagerRollback(pBt->pPager);
    if( rc2!=SQLITE_OK ){
      rc = rc2;
    }

    /* The rollback may have destroyed the pPage1->aData value.  So
    ** call btreeGetPage() on page 1 again to make
    ** sure pPage1->aData is set correctly. */
    if( btreeGetPage(pBt, 1, &pPage1, 0)==SQLITE_OK ){
      btreeSetNPage(pBt, pPage1);
      releasePageOne(pPage1);
    }
    assert( countValidCursors(pBt, 1)==0 );
    pBt->inTransaction = TRANS_READ;
    btreeClearHasContent(pBt);
  }

  btreeEndTransaction(p);
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** Start a statement subtransaction. The subtransaction can be rolled
** back independently of the main transaction. You must start a transaction
** before starting a subtransaction. The subtransaction is ended automatically
** if the main transaction commits or rolls back.
**
** Statement subtransactions are used around individual SQL statements
** that are contained within a BEGIN...COMMIT block.  If a constraint
** error occurs within the statement, the effect of that one statement
** can be rolled back without having to rollback the entire transaction.
**
** A statement sub-transaction is implemented as an anonymous savepoint. The

sqlite3.c  view on Meta::CPAN

  int rc;
  BtShared *pBt = p->pBt;
  sqlite3BtreeEnter(p);
  assert( p->inTrans==TRANS_WRITE );
  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
  assert( iStatement>0 );
  assert( iStatement>p->db->nSavepoint );
  assert( pBt->inTransaction==TRANS_WRITE );
  /* At the pager level, a statement transaction is a savepoint with
  ** an index greater than all savepoints created explicitly using
  ** SQL statements. It is illegal to open, release or rollback any
  ** such savepoints while the statement transaction savepoint is active.
  */
  rc = sqlite3PagerOpenSavepoint(pBt->pPager, iStatement);
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** The second argument to this function, op, is always SAVEPOINT_ROLLBACK
** or SAVEPOINT_RELEASE. This function either releases or rolls back the
** savepoint identified by parameter iSavepoint, depending on the value
** of op.
**
** Normally, iSavepoint is greater than or equal to zero. However, if op is
** SAVEPOINT_ROLLBACK, then iSavepoint may also be -1. In this case the
** contents of the entire transaction are rolled back. This is different
** from a normal transaction rollback, as no locks are released and the
** transaction remains open.
*/
SQLITE_PRIVATE int sqlite3BtreeSavepoint(Btree *p, int op, int iSavepoint){
  int rc = SQLITE_OK;
  if( p && p->inTrans==TRANS_WRITE ){
    BtShared *pBt = p->pBt;
    assert( op==SAVEPOINT_RELEASE || op==SAVEPOINT_ROLLBACK );
    assert( iSavepoint>=0 || (iSavepoint==-1 && op==SAVEPOINT_ROLLBACK) );
    sqlite3BtreeEnter(p);
    if( op==SAVEPOINT_ROLLBACK ){
      rc = saveAllCursors(pBt, 0, 0);
    }
    if( rc==SQLITE_OK ){
      rc = sqlite3PagerSavepoint(pBt->pPager, op, iSavepoint);
    }
    if( rc==SQLITE_OK ){
      if( iSavepoint<0 && (pBt->btsFlags & BTS_INITIALLY_EMPTY)!=0 ){
        pBt->nPage = 0;
      }
      rc = newDatabase(pBt);
      btreeSetNPage(pBt, pBt->pPage1);

      /* pBt->nPage might be zero if the database was corrupt when
      ** the transaction was started. Otherwise, it must be at least 1.  */
      assert( CORRUPT_DB || pBt->nPage>0 );
    }
    sqlite3BtreeLeave(p);
  }
  return rc;
}

/*
** Create a new cursor for the BTree whose root is on the page
** iTable. If a read-only cursor is requested, it is assumed that
** the caller already has at least a read-only transaction open
** on the database already. If a write-cursor is requested, then
** the caller is assumed to have an open write transaction.
**
** If the BTREE_WRCSR bit of wrFlag is clear, then the cursor can only
** be used for reading.  If the BTREE_WRCSR bit is set, then the cursor
** can be used for reading or for writing if other conditions for writing
** are also met.  These are the conditions that must be met in order
** for writing to be allowed:
**
** 1:  The cursor must have been opened with wrFlag containing BTREE_WRCSR
**
** 2:  Other database connections that share the same pager cache
**     but which are not in the READ_UNCOMMITTED state may not have
**     cursors open with wrFlag==0 on the same table.  Otherwise
**     the changes made by this write cursor would be visible to
**     the read cursors in the other database connection.
**
** 3:  The database must be writable (not on read-only media)
**
** 4:  There must be an active transaction.
**
** The BTREE_FORDELETE bit of wrFlag may optionally be set if BTREE_WRCSR
** is set.  If FORDELETE is set, that is a hint to the implementation that
** this cursor will only be used to seek to and delete entries of an index
** as part of a larger DELETE statement.  The FORDELETE hint is not used by
** this implementation.  But in a hypothetical alternative storage engine
** in which index entries are automatically deleted when corresponding table
** rows are deleted, the FORDELETE flag is a hint that all SEEK and DELETE
** operations on this cursor can be no-ops and all READ operations can
** return a null row (2-bytes: 0x01 0x00).
**
** No checking is done to make sure that page iTable really is the
** root page of a b-tree.  If it is not, then the cursor acquired
** will not work correctly.
**
** It is assumed that the sqlite3BtreeCursorZero() has been called
** on pCur to initialize the memory space prior to invoking this routine.
*/
static int btreeCursor(
  Btree *p,                              /* The btree */
  Pgno iTable,                           /* Root page of table to open */
  int wrFlag,                            /* 1 to write. 0 read-only */
  struct KeyInfo *pKeyInfo,              /* First arg to comparison function */
  BtCursor *pCur                         /* Space for new cursor */
){
  BtShared *pBt = p->pBt;                /* Shared b-tree handle */
  BtCursor *pX;                          /* Looping over other all cursors */

  assert( sqlite3BtreeHoldsMutex(p) );
  assert( wrFlag==0
       || wrFlag==BTREE_WRCSR
       || wrFlag==(BTREE_WRCSR|BTREE_FORDELETE)
  );

  /* The following assert statements verify that if this is a sharable
  ** b-tree database, the connection is holding the required table locks,
  ** and that no other connection has any open cursor that conflicts with
  ** this lock.  The iTable<1 term disables the check for corrupt schemas. */
  assert( hasSharedCacheTableLock(p, iTable, pKeyInfo!=0, (wrFlag?2:1))
          || iTable<1 );
  assert( wrFlag==0 || !hasReadConflicts(p, iTable) );

  /* Assert that the caller has opened the required transaction. */
  assert( p->inTrans>TRANS_NONE );
  assert( wrFlag==0 || p->inTrans==TRANS_WRITE );
  assert( pBt->pPage1 && pBt->pPage1->aData );
  assert( wrFlag==0 || (pBt->btsFlags & BTS_READ_ONLY)==0 );

  if( iTable<=1 ){
    if( iTable<1 ){
      return SQLITE_CORRUPT_BKPT;
    }else if( btreePagecount(pBt)==0 ){
      assert( wrFlag==0 );
      iTable = 0;
    }
  }

  /* Now that no other errors can occur, finish filling in the BtCursor
  ** variables and link the cursor into the BtShared list.  */
  pCur->pgnoRoot = iTable;
  pCur->iPage = -1;
  pCur->pKeyInfo = pKeyInfo;
  pCur->pBtree = p;
  pCur->pBt = pBt;
  pCur->curFlags = 0;
  /* If there are two or more cursors on the same btree, then all such
  ** cursors *must* have the BTCF_Multiple flag set. */
  for(pX=pBt->pCursor; pX; pX=pX->pNext){
    if( pX->pgnoRoot==iTable ){
      pX->curFlags |= BTCF_Multiple;
      pCur->curFlags = BTCF_Multiple;
    }
  }
  pCur->eState = CURSOR_INVALID;
  pCur->pNext = pBt->pCursor;
  pBt->pCursor = pCur;
  if( wrFlag ){
    pCur->curFlags |= BTCF_WriteFlag;
    pCur->curPagerFlags = 0;
    if( pBt->pTmpSpace==0 ) return allocateTempSpace(pBt);
  }else{
    pCur->curPagerFlags = PAGER_GET_READONLY;
  }
  return SQLITE_OK;
}
static int btreeCursorWithLock(
  Btree *p,                              /* The btree */
  Pgno iTable,                           /* Root page of table to open */
  int wrFlag,                            /* 1 to write. 0 read-only */
  struct KeyInfo *pKeyInfo,              /* First arg to comparison function */
  BtCursor *pCur                         /* Space for new cursor */
){
  int rc;
  sqlite3BtreeEnter(p);
  rc = btreeCursor(p, iTable, wrFlag, pKeyInfo, pCur);
  sqlite3BtreeLeave(p);
  return rc;
}
SQLITE_PRIVATE int sqlite3BtreeCursor(
  Btree *p,                                   /* The btree */
  Pgno iTable,                                /* Root page of table to open */
  int wrFlag,                                 /* 1 to write. 0 read-only */
  struct KeyInfo *pKeyInfo,                   /* First arg to xCompare() */
  BtCursor *pCur                              /* Write new cursor here */
){
  if( p->sharable ){
    return btreeCursorWithLock(p, iTable, wrFlag, pKeyInfo, pCur);
  }else{
    return btreeCursor(p, iTable, wrFlag, pKeyInfo, pCur);
  }
}

/*
** Return the size of a BtCursor object in bytes.
**
** This interfaces is needed so that users of cursors can preallocate
** sufficient storage to hold a cursor.  The BtCursor object is opaque
** to users so they cannot do the sizeof() themselves - they must call
** this routine.
*/
SQLITE_PRIVATE int sqlite3BtreeCursorSize(void){
  return ROUND8(sizeof(BtCursor));
}

#ifdef SQLITE_DEBUG
/*
** Return true if and only if the Btree object will be automatically
** closed with the BtCursor closes.  This is used within assert() statements
** only.
*/
SQLITE_PRIVATE int sqlite3BtreeClosesWithCursor(
  Btree *pBtree,       /* the btree object */
  BtCursor *pCur       /* Corresponding cursor */
){
  BtShared *pBt = pBtree->pBt;
  if( (pBt->openFlags & BTREE_SINGLE)==0 ) return 0;
  if( pBt->pCursor!=pCur ) return 0;
  if( pCur->pNext!=0 ) return 0;
  if( pCur->pBtree!=pBtree ) return 0;
  return 1;
}
#endif

/*
** Initialize memory that will be converted into a BtCursor object.
**
** The simple approach here would be to memset() the entire object
** to zero.  But it turns out that the apPage[] and aiIdx[] arrays
** do not need to be zeroed and they are large, so we can save a lot
** of run-time by skipping the initialization of those elements.
*/
SQLITE_PRIVATE void sqlite3BtreeCursorZero(BtCursor *p){
  memset(p, 0, offsetof(BtCursor, BTCURSOR_FIRST_UNINIT));
}

/*
** Close a cursor.  The read lock on the database file is released
** when the last cursor is closed.
*/
SQLITE_PRIVATE int sqlite3BtreeCloseCursor(BtCursor *pCur){
  Btree *pBtree = pCur->pBtree;
  if( pBtree ){
    BtShared *pBt = pCur->pBt;
    sqlite3BtreeEnter(pBtree);
    assert( pBt->pCursor!=0 );
    if( pBt->pCursor==pCur ){
      pBt->pCursor = pCur->pNext;
    }else{
      BtCursor *pPrev = pBt->pCursor;
      do{
        if( pPrev->pNext==pCur ){
          pPrev->pNext = pCur->pNext;
          break;
        }
        pPrev = pPrev->pNext;
      }while( ALWAYS(pPrev) );
    }
    btreeReleaseAllCursorPages(pCur);
    unlockBtreeIfUnused(pBt);
    sqlite3_free(pCur->aOverflow);
    sqlite3_free(pCur->pKey);
    if( (pBt->openFlags & BTREE_SINGLE) && pBt->pCursor==0 ){
      /* Since the BtShared is not sharable, there is no need to
      ** worry about the missing sqlite3BtreeLeave() call here.  */
      assert( pBtree->sharable==0 );
      sqlite3BtreeClose(pBtree);
    }else{
      sqlite3BtreeLeave(pBtree);
    }
    pCur->pBtree = 0;
  }
  return SQLITE_OK;
}

/*
** Make sure the BtCursor* given in the argument has a valid
** BtCursor.info structure.  If it is not already valid, call
** btreeParseCell() to fill it in.
**
** BtCursor.info is a cache of the information in the current cell.
** Using this cache reduces the number of calls to btreeParseCell().
*/
#ifndef NDEBUG
  static int cellInfoEqual(CellInfo *a, CellInfo *b){
    if( a->nKey!=b->nKey ) return 0;
    if( a->pPayload!=b->pPayload ) return 0;
    if( a->nPayload!=b->nPayload ) return 0;
    if( a->nLocal!=b->nLocal ) return 0;
    if( a->nSize!=b->nSize ) return 0;
    return 1;
  }
  static void assertCellInfo(BtCursor *pCur){
    CellInfo info;
    memset(&info, 0, sizeof(info));
    btreeParseCell(pCur->pPage, pCur->ix, &info);
    assert( CORRUPT_DB || cellInfoEqual(&info, &pCur->info) );
  }
#else
  #define assertCellInfo(x)
#endif
static SQLITE_NOINLINE void getCellInfo(BtCursor *pCur){
  if( pCur->info.nSize==0 ){
    pCur->curFlags |= BTCF_ValidNKey;
    btreeParseCell(pCur->pPage,pCur->ix,&pCur->info);
  }else{
    assertCellInfo(pCur);
  }
}

#ifndef NDEBUG  /* The next routine used only within assert() statements */
/*
** Return true if the given BtCursor is valid.  A valid cursor is one
** that is currently pointing to a row in a (non-empty) table.
** This is a verification routine is used only within assert() statements.
*/
SQLITE_PRIVATE int sqlite3BtreeCursorIsValid(BtCursor *pCur){
  return pCur && pCur->eState==CURSOR_VALID;
}
#endif /* NDEBUG */
SQLITE_PRIVATE int sqlite3BtreeCursorIsValidNN(BtCursor *pCur){
  assert( pCur!=0 );
  return pCur->eState==CURSOR_VALID;
}

/*
** Return the value of the integer key or "rowid" for a table btree.
** This routine is only valid for a cursor that is pointing into a
** ordinary table btree.  If the cursor points to an index btree or
** is invalid, the result of this routine is undefined.
*/
SQLITE_PRIVATE i64 sqlite3BtreeIntegerKey(BtCursor *pCur){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->curIntKey );
  getCellInfo(pCur);
  return pCur->info.nKey;
}

/*
** Pin or unpin a cursor.
*/
SQLITE_PRIVATE void sqlite3BtreeCursorPin(BtCursor *pCur){
  assert( (pCur->curFlags & BTCF_Pinned)==0 );
  pCur->curFlags |= BTCF_Pinned;
}
SQLITE_PRIVATE void sqlite3BtreeCursorUnpin(BtCursor *pCur){
  assert( (pCur->curFlags & BTCF_Pinned)!=0 );
  pCur->curFlags &= ~BTCF_Pinned;
}

/*
** Return the offset into the database file for the start of the
** payload to which the cursor is pointing.
*/
SQLITE_PRIVATE i64 sqlite3BtreeOffset(BtCursor *pCur){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  getCellInfo(pCur);
  return (i64)pCur->pBt->pageSize*((i64)pCur->pPage->pgno - 1) +
         (i64)(pCur->info.pPayload - pCur->pPage->aData);
}

/*
** Return the number of bytes of payload for the entry that pCur is
** currently pointing to.  For table btrees, this will be the amount
** of data.  For index btrees, this will be the size of the key.
**
** The caller must guarantee that the cursor is pointing to a non-NULL
** valid entry.  In other words, the calling procedure must guarantee
** that the cursor has Cursor.eState==CURSOR_VALID.
*/
SQLITE_PRIVATE u32 sqlite3BtreePayloadSize(BtCursor *pCur){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  getCellInfo(pCur);
  return pCur->info.nPayload;
}

/*
** Return an upper bound on the size of any record for the table
** that the cursor is pointing into.
**
** This is an optimization.  Everything will still work if this
** routine always returns 2147483647 (which is the largest record
** that SQLite can handle) or more.  But returning a smaller value might
** prevent large memory allocations when trying to interpret a
** corrupt database.
**
** The current implementation merely returns the size of the underlying
** database file.
*/
SQLITE_PRIVATE sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor *pCur){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  return pCur->pBt->pageSize * (sqlite3_int64)pCur->pBt->nPage;
}

/*
** Given the page number of an overflow page in the database (parameter
** ovfl), this function finds the page number of the next page in the
** linked list of overflow pages. If possible, it uses the auto-vacuum
** pointer-map data instead of reading the content of page ovfl to do so.
**
** If an error occurs an SQLite error code is returned. Otherwise:
**
** The page number of the next overflow page in the linked list is
** written to *pPgnoNext. If page ovfl is the last page in its linked
** list, *pPgnoNext is set to zero.
**
** If ppPage is not NULL, and a reference to the MemPage object corresponding
** to page number pOvfl was obtained, then *ppPage is set to point to that
** reference. It is the responsibility of the caller to call releasePage()
** on *ppPage to free the reference. In no reference was obtained (because
** the pointer-map was used to obtain the value for *pPgnoNext), then
** *ppPage is set to zero.
*/
static int getOverflowPage(
  BtShared *pBt,               /* The database file */
  Pgno ovfl,                   /* Current overflow page number */
  MemPage **ppPage,            /* OUT: MemPage handle (may be NULL) */
  Pgno *pPgnoNext              /* OUT: Next overflow page number */
){
  Pgno next = 0;
  MemPage *pPage = 0;
  int rc = SQLITE_OK;

  assert( sqlite3_mutex_held(pBt->mutex) );
  assert(pPgnoNext);

#ifndef SQLITE_OMIT_AUTOVACUUM
  /* Try to find the next page in the overflow list using the
  ** autovacuum pointer-map pages. Guess that the next page in
  ** the overflow list is page number (ovfl+1). If that guess turns
  ** out to be wrong, fall back to loading the data of page
  ** number ovfl to determine the next page number.
  */
  if( pBt->autoVacuum ){
    Pgno pgno;
    Pgno iGuess = ovfl+1;
    u8 eType;

    while( PTRMAP_ISPAGE(pBt, iGuess) || iGuess==PENDING_BYTE_PAGE(pBt) ){
      iGuess++;
    }

    if( iGuess<=btreePagecount(pBt) ){
      rc = ptrmapGet(pBt, iGuess, &eType, &pgno);
      if( rc==SQLITE_OK && eType==PTRMAP_OVERFLOW2 && pgno==ovfl ){
        next = iGuess;
        rc = SQLITE_DONE;
      }
    }
  }
#endif

  assert( next==0 || rc==SQLITE_DONE );
  if( rc==SQLITE_OK ){
    rc = btreeGetPage(pBt, ovfl, &pPage, (ppPage==0) ? PAGER_GET_READONLY : 0);
    assert( rc==SQLITE_OK || pPage==0 );
    if( rc==SQLITE_OK ){
      next = get4byte(pPage->aData);
    }
  }

  *pPgnoNext = next;
  if( ppPage ){
    *ppPage = pPage;
  }else{
    releasePage(pPage);
  }
  return (rc==SQLITE_DONE ? SQLITE_OK : rc);
}

/*
** Copy data from a buffer to a page, or from a page to a buffer.
**
** pPayload is a pointer to data stored on database page pDbPage.
** If argument eOp is false, then nByte bytes of data are copied
** from pPayload to the buffer pointed at by pBuf. If eOp is true,
** then sqlite3PagerWrite() is called on pDbPage and nByte bytes
** of data are copied from the buffer pBuf to pPayload.
**
** SQLITE_OK is returned on success, otherwise an error code.
*/
static int copyPayload(
  void *pPayload,           /* Pointer to page data */
  void *pBuf,               /* Pointer to buffer */
  int nByte,                /* Number of bytes to copy */
  int eOp,                  /* 0 -> copy from page, 1 -> copy to page */
  DbPage *pDbPage           /* Page containing pPayload */
){
  if( eOp ){
    /* Copy data from buffer to page (a write operation) */
    int rc = sqlite3PagerWrite(pDbPage);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    memcpy(pPayload, pBuf, nByte);
  }else{
    /* Copy data from page to buffer (a read operation) */
    memcpy(pBuf, pPayload, nByte);
  }
  return SQLITE_OK;
}

/*
** This function is used to read or overwrite payload information
** for the entry that the pCur cursor is pointing to. The eOp
** argument is interpreted as follows:
**
**   0: The operation is a read. Populate the overflow cache.
**   1: The operation is a write. Populate the overflow cache.
**
** A total of "amt" bytes are read or written beginning at "offset".
** Data is read to or from the buffer pBuf.
**
** The content being read or written might appear on the main page
** or be scattered out on multiple overflow pages.
**
** If the current cursor entry uses one or more overflow pages
** this function may allocate space for and lazily populate
** the overflow page-list cache array (BtCursor.aOverflow).
** Subsequent calls use this cache to make seeking to the supplied offset
** more efficient.
**
** Once an overflow page-list cache has been allocated, it must be
** invalidated if some other cursor writes to the same table, or if
** the cursor is moved to a different row. Additionally, in auto-vacuum
** mode, the following events may invalidate an overflow page-list cache.
**
**   * An incremental vacuum,
**   * A commit in auto_vacuum="full" mode,
**   * Creating a table (may require moving an overflow page).
*/
static int accessPayload(
  BtCursor *pCur,      /* Cursor pointing to entry to read from */
  u32 offset,          /* Begin reading this far into payload */
  u32 amt,             /* Read this many bytes */
  unsigned char *pBuf, /* Write the bytes into this buffer */
  int eOp              /* zero to read. non-zero to write. */
){
  unsigned char *aPayload;
  int rc = SQLITE_OK;
  int iIdx = 0;
  MemPage *pPage = pCur->pPage;               /* Btree page of current entry */
  BtShared *pBt = pCur->pBt;                  /* Btree this cursor belongs to */
#ifdef SQLITE_DIRECT_OVERFLOW_READ
  unsigned char * const pBufStart = pBuf;     /* Start of original out buffer */
#endif

  assert( pPage );
  assert( eOp==0 || eOp==1 );
  assert( pCur->eState==CURSOR_VALID );
  if( pCur->ix>=pPage->nCell ){
    return SQLITE_CORRUPT_PAGE(pPage);
  }
  assert( cursorHoldsMutex(pCur) );

  getCellInfo(pCur);
  aPayload = pCur->info.pPayload;
  assert( offset+amt <= pCur->info.nPayload );

  assert( aPayload > pPage->aData );
  if( (uptr)(aPayload - pPage->aData) > (pBt->usableSize - pCur->info.nLocal) ){
    /* Trying to read or write past the end of the data is an error.  The
    ** conditional above is really:
    **    &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize]
    ** but is recast into its current form to avoid integer overflow problems
    */
    return SQLITE_CORRUPT_PAGE(pPage);
  }

  /* Check if data must be read/written to/from the btree page itself. */
  if( offset<pCur->info.nLocal ){
    int a = amt;
    if( a+offset>pCur->info.nLocal ){
      a = pCur->info.nLocal - offset;
    }
    rc = copyPayload(&aPayload[offset], pBuf, a, eOp, pPage->pDbPage);
    offset = 0;
    pBuf += a;
    amt -= a;
  }else{
    offset -= pCur->info.nLocal;
  }


  if( rc==SQLITE_OK && amt>0 ){
    const u32 ovflSize = pBt->usableSize - 4;  /* Bytes content per ovfl page */
    Pgno nextPage;

    nextPage = get4byte(&aPayload[pCur->info.nLocal]);

    /* If the BtCursor.aOverflow[] has not been allocated, allocate it now.
    **
    ** The aOverflow[] array is sized at one entry for each overflow page
    ** in the overflow chain. The page number of the first overflow page is
    ** stored in aOverflow[0], etc. A value of 0 in the aOverflow[] array
    ** means "not yet known" (the cache is lazily populated).
    */
    if( (pCur->curFlags & BTCF_ValidOvfl)==0 ){
      int nOvfl = (pCur->info.nPayload-pCur->info.nLocal+ovflSize-1)/ovflSize;
      if( pCur->aOverflow==0
       || nOvfl*(int)sizeof(Pgno) > sqlite3MallocSize(pCur->aOverflow)
      ){
        Pgno *aNew;
        if( sqlite3FaultSim(413) ){
          aNew = 0;
        }else{
          aNew = (Pgno*)sqlite3Realloc(pCur->aOverflow, nOvfl*2*sizeof(Pgno));
        }
        if( aNew==0 ){
          return SQLITE_NOMEM_BKPT;
        }else{
          pCur->aOverflow = aNew;
        }
      }

sqlite3.c  view on Meta::CPAN

#ifdef SQLITE_DIRECT_OVERFLOW_READ
        /* If all the following are true:
        **
        **   1) this is a read operation, and
        **   2) data is required from the start of this overflow page, and
        **   3) there are no dirty pages in the page-cache
        **   4) the database is file-backed, and
        **   5) the page is not in the WAL file
        **   6) at least 4 bytes have already been read into the output buffer
        **
        ** then data can be read directly from the database file into the
        ** output buffer, bypassing the page-cache altogether. This speeds
        ** up loading large records that span many overflow pages.
        */
        if( eOp==0                                             /* (1) */
         && offset==0                                          /* (2) */
         && sqlite3PagerDirectReadOk(pBt->pPager, nextPage)    /* (3,4,5) */
         && &pBuf[-4]>=pBufStart                               /* (6) */
        ){
          sqlite3_file *fd = sqlite3PagerFile(pBt->pPager);
          u8 aSave[4];
          u8 *aWrite = &pBuf[-4];
          assert( aWrite>=pBufStart );                         /* due to (6) */
          memcpy(aSave, aWrite, 4);
          rc = sqlite3OsRead(fd, aWrite, a+4, (i64)pBt->pageSize*(nextPage-1));
          nextPage = get4byte(aWrite);
          memcpy(aWrite, aSave, 4);
        }else
#endif

        {
          DbPage *pDbPage;
          rc = sqlite3PagerGet(pBt->pPager, nextPage, &pDbPage,
              (eOp==0 ? PAGER_GET_READONLY : 0)
          );
          if( rc==SQLITE_OK ){
            aPayload = sqlite3PagerGetData(pDbPage);
            nextPage = get4byte(aPayload);
            rc = copyPayload(&aPayload[offset+4], pBuf, a, eOp, pDbPage);
            sqlite3PagerUnref(pDbPage);
            offset = 0;
          }
        }
        amt -= a;
        if( amt==0 ) return rc;
        pBuf += a;
      }
      if( rc ) break;
      iIdx++;
    }
  }

  if( rc==SQLITE_OK && amt>0 ){
    /* Overflow chain ends prematurely */
    return SQLITE_CORRUPT_PAGE(pPage);
  }
  return rc;
}

/*
** Read part of the payload for the row at which that cursor pCur is currently
** pointing.  "amt" bytes will be transferred into pBuf[].  The transfer
** begins at "offset".
**
** pCur can be pointing to either a table or an index b-tree.
** If pointing to a table btree, then the content section is read.  If
** pCur is pointing to an index b-tree then the key section is read.
**
** For sqlite3BtreePayload(), the caller must ensure that pCur is pointing
** to a valid row in the table.  For sqlite3BtreePayloadChecked(), the
** cursor might be invalid or might need to be restored before being read.
**
** Return SQLITE_OK on success or an error code if anything goes
** wrong.  An error is returned if "offset+amt" is larger than
** the available payload.
*/
SQLITE_PRIVATE int sqlite3BtreePayload(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
  assert( cursorHoldsMutex(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->iPage>=0 && pCur->pPage );
  return accessPayload(pCur, offset, amt, (unsigned char*)pBuf, 0);
}

/*
** This variant of sqlite3BtreePayload() works even if the cursor has not
** in the CURSOR_VALID state.  It is only used by the sqlite3_blob_read()
** interface.
*/
#ifndef SQLITE_OMIT_INCRBLOB
static SQLITE_NOINLINE int accessPayloadChecked(
  BtCursor *pCur,
  u32 offset,
  u32 amt,
  void *pBuf
){
  int rc;
  if ( pCur->eState==CURSOR_INVALID ){
    return SQLITE_ABORT;
  }
  assert( cursorOwnsBtShared(pCur) );
  rc = btreeRestoreCursorPosition(pCur);
  return rc ? rc : accessPayload(pCur, offset, amt, pBuf, 0);
}
SQLITE_PRIVATE int sqlite3BtreePayloadChecked(BtCursor *pCur, u32 offset, u32 amt, void *pBuf){
  if( pCur->eState==CURSOR_VALID ){
    assert( cursorOwnsBtShared(pCur) );
    return accessPayload(pCur, offset, amt, pBuf, 0);
  }else{
    return accessPayloadChecked(pCur, offset, amt, pBuf);
  }
}
#endif /* SQLITE_OMIT_INCRBLOB */

/*
** Return a pointer to payload information from the entry that the
** pCur cursor is pointing to.  The pointer is to the beginning of
** the key if index btrees (pPage->intKey==0) and is the data for
** table btrees (pPage->intKey==1). The number of bytes of available
** key/data is written into *pAmt.  If *pAmt==0, then the value
** returned will not be a valid pointer.
**
** This routine is an optimization.  It is common for the entire key
** and data to fit on the local page and for there to be no overflow
** pages.  When that is so, this routine can be used to access the
** key and data without making a copy.  If the key and/or data spills
** onto overflow pages, then accessPayload() must be used to reassemble
** the key/data and copy it into a preallocated buffer.
**
** The pointer returned by this routine looks directly into the cached
** page of the database.  The data might change or move the next time
** any btree routine is called.
*/
static const void *fetchPayload(
  BtCursor *pCur,      /* Cursor pointing to entry to read from */
  u32 *pAmt            /* Write the number of available bytes here */
){
  int amt;
  assert( pCur!=0 && pCur->iPage>=0 && pCur->pPage);
  assert( pCur->eState==CURSOR_VALID );
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
  assert( cursorOwnsBtShared(pCur) );
  assert( pCur->ix<pCur->pPage->nCell || CORRUPT_DB );
  assert( pCur->info.nSize>0 );
  assert( pCur->info.pPayload>pCur->pPage->aData || CORRUPT_DB );
  assert( pCur->info.pPayload<pCur->pPage->aDataEnd ||CORRUPT_DB);
  amt = pCur->info.nLocal;
  if( amt>(int)(pCur->pPage->aDataEnd - pCur->info.pPayload) ){
    /* There is too little space on the page for the expected amount
    ** of local content. Database must be corrupt. */
    assert( CORRUPT_DB );
    amt = MAX(0, (int)(pCur->pPage->aDataEnd - pCur->info.pPayload));
  }
  *pAmt = (u32)amt;
  return (void*)pCur->info.pPayload;
}


/*
** For the entry that cursor pCur is point to, return as
** many bytes of the key or data as are available on the local
** b-tree page.  Write the number of available bytes into *pAmt.
**
** The pointer returned is ephemeral.  The key/data may move
** or be destroyed on the next call to any Btree routine,
** including calls from other threads against the same cache.
** Hence, a mutex on the BtShared should be held prior to calling
** this routine.
**
** These routines is used to get quick access to key and data
** in the common case where no overflow pages are used.
*/
SQLITE_PRIVATE const void *sqlite3BtreePayloadFetch(BtCursor *pCur, u32 *pAmt){
  return fetchPayload(pCur, pAmt);
}


/*
** Move the cursor down to a new child page.  The newPgno argument is the
** page number of the child page to move to.
**
** This function returns SQLITE_CORRUPT if the page-header flags field of
** the new child page does not match the flags field of the parent (i.e.
** if an intkey page appears to be the parent of a non-intkey page, or
** vice-versa).
*/
static int moveToChild(BtCursor *pCur, u32 newPgno){
  int rc;
  assert( cursorOwnsBtShared(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->iPage<BTCURSOR_MAX_DEPTH );
  assert( pCur->iPage>=0 );
  if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
    return SQLITE_CORRUPT_BKPT;
  }
  pCur->info.nSize = 0;
  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
  pCur->aiIdx[pCur->iPage] = pCur->ix;
  pCur->apPage[pCur->iPage] = pCur->pPage;
  pCur->ix = 0;
  pCur->iPage++;
  rc = getAndInitPage(pCur->pBt, newPgno, &pCur->pPage, pCur->curPagerFlags);
  assert( pCur->pPage!=0 || rc!=SQLITE_OK );
  if( rc==SQLITE_OK
   && (pCur->pPage->nCell<1 || pCur->pPage->intKey!=pCur->curIntKey)
  ){
    releasePage(pCur->pPage);
    rc = SQLITE_CORRUPT_PGNO(newPgno);
  }
  if( rc ){
    pCur->pPage = pCur->apPage[--pCur->iPage];
  }
  return rc;
}

#ifdef SQLITE_DEBUG
/*
** Page pParent is an internal (non-leaf) tree page. This function
** asserts that page number iChild is the left-child if the iIdx'th
** cell in page pParent. Or, if iIdx is equal to the total number of
** cells in pParent, that page number iChild is the right-child of
** the page.
*/
static void assertParentIndex(MemPage *pParent, int iIdx, Pgno iChild){
  if( CORRUPT_DB ) return;  /* The conditions tested below might not be true
                            ** in a corrupt database */
  assert( iIdx<=pParent->nCell );
  if( iIdx==pParent->nCell ){
    assert( get4byte(&pParent->aData[pParent->hdrOffset+8])==iChild );
  }else{
    assert( get4byte(findCell(pParent, iIdx))==iChild );
  }
}
#else
#  define assertParentIndex(x,y,z)
#endif

/*
** Move the cursor up to the parent page.
**
** pCur->idx is set to the cell index that contains the pointer
** to the page we are coming from.  If we are coming from the
** right-most child page then pCur->idx is set to one more than
** the largest cell index.
*/
static void moveToParent(BtCursor *pCur){
  MemPage *pLeaf;
  assert( cursorOwnsBtShared(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->iPage>0 );
  assert( pCur->pPage );
  assertParentIndex(
    pCur->apPage[pCur->iPage-1],
    pCur->aiIdx[pCur->iPage-1],
    pCur->pPage->pgno
  );
  testcase( pCur->aiIdx[pCur->iPage-1] > pCur->apPage[pCur->iPage-1]->nCell );
  pCur->info.nSize = 0;
  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
  pCur->ix = pCur->aiIdx[pCur->iPage-1];
  pLeaf = pCur->pPage;
  pCur->pPage = pCur->apPage[--pCur->iPage];
  releasePageNotNull(pLeaf);
}

/*
** Move the cursor to point to the root page of its b-tree structure.
**
** If the table has a virtual root page, then the cursor is moved to point
** to the virtual root page instead of the actual root page. A table has a
** virtual root page when the actual root page contains no cells and a
** single child page. This can only happen with the table rooted at page 1.
**
** If the b-tree structure is empty, the cursor state is set to
** CURSOR_INVALID and this routine returns SQLITE_EMPTY. Otherwise,
** the cursor is set to point to the first cell located on the root
** (or virtual root) page and the cursor state is set to CURSOR_VALID.
**
** If this function returns successfully, it may be assumed that the
** page-header flags indicate that the [virtual] root-page is the expected
** kind of b-tree page (i.e. if when opening the cursor the caller did not
** specify a KeyInfo structure the flags byte is set to 0x05 or 0x0D,
** indicating a table b-tree, or if the caller did specify a KeyInfo
** structure the flags byte is set to 0x02 or 0x0A, indicating an index
** b-tree).
*/
static int moveToRoot(BtCursor *pCur){
  MemPage *pRoot;
  int rc = SQLITE_OK;

  assert( cursorOwnsBtShared(pCur) );
  assert( CURSOR_INVALID < CURSOR_REQUIRESEEK );
  assert( CURSOR_VALID   < CURSOR_REQUIRESEEK );
  assert( CURSOR_FAULT   > CURSOR_REQUIRESEEK );
  assert( pCur->eState < CURSOR_REQUIRESEEK || pCur->iPage<0 );
  assert( pCur->pgnoRoot>0 || pCur->iPage<0 );

  if( pCur->iPage>=0 ){
    if( pCur->iPage ){
      releasePageNotNull(pCur->pPage);
      while( --pCur->iPage ){
        releasePageNotNull(pCur->apPage[pCur->iPage]);
      }
      pRoot = pCur->pPage = pCur->apPage[0];
      goto skip_init;
    }
  }else if( pCur->pgnoRoot==0 ){
    pCur->eState = CURSOR_INVALID;
    return SQLITE_EMPTY;
  }else{
    assert( pCur->iPage==(-1) );
    if( pCur->eState>=CURSOR_REQUIRESEEK ){
      if( pCur->eState==CURSOR_FAULT ){
        assert( pCur->skipNext!=SQLITE_OK );
        return pCur->skipNext;
      }
      sqlite3BtreeClearCursor(pCur);
    }
    rc = getAndInitPage(pCur->pBt, pCur->pgnoRoot, &pCur->pPage,
                        pCur->curPagerFlags);
    if( rc!=SQLITE_OK ){
      pCur->eState = CURSOR_INVALID;
      return rc;
    }
    pCur->iPage = 0;
    pCur->curIntKey = pCur->pPage->intKey;
  }
  pRoot = pCur->pPage;
  assert( pRoot->pgno==pCur->pgnoRoot || CORRUPT_DB );

  /* If pCur->pKeyInfo is not NULL, then the caller that opened this cursor
  ** expected to open it on an index b-tree. Otherwise, if pKeyInfo is
  ** NULL, the caller expects a table b-tree. If this is not the case,
  ** return an SQLITE_CORRUPT error.
  **
  ** Earlier versions of SQLite assumed that this test could not fail
  ** if the root page was already loaded when this function was called (i.e.
  ** if pCur->iPage>=0). But this is not so if the database is corrupted
  ** in such a way that page pRoot is linked into a second b-tree table
  ** (or the freelist).  */
  assert( pRoot->intKey==1 || pRoot->intKey==0 );
  if( pRoot->isInit==0 || (pCur->pKeyInfo==0)!=pRoot->intKey ){
    return SQLITE_CORRUPT_PAGE(pCur->pPage);
  }

skip_init:
  pCur->ix = 0;
  pCur->info.nSize = 0;
  pCur->curFlags &= ~(BTCF_AtLast|BTCF_ValidNKey|BTCF_ValidOvfl);

  if( pRoot->nCell>0 ){
    pCur->eState = CURSOR_VALID;
  }else if( !pRoot->leaf ){
    Pgno subpage;
    if( pRoot->pgno!=1 ) return SQLITE_CORRUPT_BKPT;
    subpage = get4byte(&pRoot->aData[pRoot->hdrOffset+8]);
    pCur->eState = CURSOR_VALID;
    rc = moveToChild(pCur, subpage);
  }else{
    pCur->eState = CURSOR_INVALID;
    rc = SQLITE_EMPTY;
  }
  return rc;
}

/*
** Move the cursor down to the left-most leaf entry beneath the
** entry to which it is currently pointing.
**
** The left-most leaf is the one with the smallest key - the first
** in ascending order.
*/
static int moveToLeftmost(BtCursor *pCur){
  Pgno pgno;
  int rc = SQLITE_OK;
  MemPage *pPage;

  assert( cursorOwnsBtShared(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  while( rc==SQLITE_OK && !(pPage = pCur->pPage)->leaf ){
    assert( pCur->ix<pPage->nCell );
    pgno = get4byte(findCell(pPage, pCur->ix));
    rc = moveToChild(pCur, pgno);
  }
  return rc;
}

/*
** Move the cursor down to the right-most leaf entry beneath the
** page to which it is currently pointing.  Notice the difference
** between moveToLeftmost() and moveToRightmost().  moveToLeftmost()
** finds the left-most entry beneath the *entry* whereas moveToRightmost()
** finds the right-most entry beneath the *page*.
**
** The right-most entry is the one with the largest key - the last
** key in ascending order.
*/
static int moveToRightmost(BtCursor *pCur){
  Pgno pgno;
  int rc = SQLITE_OK;
  MemPage *pPage = 0;

  assert( cursorOwnsBtShared(pCur) );
  assert( pCur->eState==CURSOR_VALID );
  while( !(pPage = pCur->pPage)->leaf ){
    pgno = get4byte(&pPage->aData[pPage->hdrOffset+8]);
    pCur->ix = pPage->nCell;
    rc = moveToChild(pCur, pgno);
    if( rc ) return rc;
  }
  pCur->ix = pPage->nCell-1;
  assert( pCur->info.nSize==0 );
  assert( (pCur->curFlags & BTCF_ValidNKey)==0 );
  return SQLITE_OK;
}

/* Move the cursor to the first entry in the table.  Return SQLITE_OK
** on success.  Set *pRes to 0 if the cursor actually points to something
** or set *pRes to 1 if the table is empty.
*/
SQLITE_PRIVATE int sqlite3BtreeFirst(BtCursor *pCur, int *pRes){
  int rc;

  assert( cursorOwnsBtShared(pCur) );
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
  rc = moveToRoot(pCur);
  if( rc==SQLITE_OK ){
    assert( pCur->pPage->nCell>0 );
    *pRes = 0;
    rc = moveToLeftmost(pCur);
  }else if( rc==SQLITE_EMPTY ){
    assert( pCur->pgnoRoot==0 || (pCur->pPage!=0 && pCur->pPage->nCell==0) );
    *pRes = 1;
    rc = SQLITE_OK;
  }
  return rc;
}

/* Set *pRes to 1 (true) if the BTree pointed to by cursor pCur contains zero
** rows of content.  Set *pRes to 0 (false) if the table contains content.
** Return SQLITE_OK on success or some error code (ex: SQLITE_NOMEM) if
** something goes wrong.
*/
SQLITE_PRIVATE int sqlite3BtreeIsEmpty(BtCursor *pCur, int *pRes){
  int rc;

  assert( cursorOwnsBtShared(pCur) );
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
  if( pCur->eState==CURSOR_VALID ){
    *pRes = 0;
    return SQLITE_OK;
  }
  rc = moveToRoot(pCur);
  if( rc==SQLITE_EMPTY ){
    *pRes = 1;
    rc = SQLITE_OK;
  }else{
    *pRes = 0;
  }
  return rc;
}

#ifdef SQLITE_DEBUG
/* The cursors is CURSOR_VALID and has BTCF_AtLast set.  Verify that
** this flags are true for a consistent database.
**
** This routine is is called from within assert() statements only.
** It is an internal verification routine and does not appear in production
** builds.
*/
static int cursorIsAtLastEntry(BtCursor *pCur){
  int ii;
  for(ii=0; ii<pCur->iPage; ii++){
    if( pCur->aiIdx[ii]!=pCur->apPage[ii]->nCell ) return 0;
  }
  return pCur->ix==pCur->pPage->nCell-1 && pCur->pPage->leaf!=0;
}
#endif

/* Move the cursor to the last entry in the table.  Return SQLITE_OK
** on success.  Set *pRes to 0 if the cursor actually points to something
** or set *pRes to 1 if the table is empty.
*/
static SQLITE_NOINLINE int btreeLast(BtCursor *pCur, int *pRes){
  int rc = moveToRoot(pCur);
  if( rc==SQLITE_OK ){
    assert( pCur->eState==CURSOR_VALID );
    *pRes = 0;
    rc = moveToRightmost(pCur);
    if( rc==SQLITE_OK ){
      pCur->curFlags |= BTCF_AtLast;
    }else{
      pCur->curFlags &= ~BTCF_AtLast;
    }
  }else if( rc==SQLITE_EMPTY ){
    assert( pCur->pgnoRoot==0 || pCur->pPage->nCell==0 );
    *pRes = 1;
    rc = SQLITE_OK;
  }
  return rc;
}
SQLITE_PRIVATE int sqlite3BtreeLast(BtCursor *pCur, int *pRes){
  assert( cursorOwnsBtShared(pCur) );
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );

  /* If the cursor already points to the last entry, this is a no-op. */
  if( CURSOR_VALID==pCur->eState && (pCur->curFlags & BTCF_AtLast)!=0 ){
    assert( cursorIsAtLastEntry(pCur) || CORRUPT_DB );
    *pRes = 0;
    return SQLITE_OK;
  }
  return btreeLast(pCur, pRes);
}

/* Move the cursor so that it points to an entry in a table (a.k.a INTKEY)
** table near the key intKey.   Return a success code.
**
** If an exact match is not found, then the cursor is always
** left pointing at a leaf page which would hold the entry if it
** were present.  The cursor might point to an entry that comes
** before or after the key.
**
** An integer is written into *pRes which is the result of
** comparing the key with the entry to which the cursor is
** pointing.  The meaning of the integer written into
** *pRes is as follows:
**
**     *pRes<0      The cursor is left pointing at an entry that
**                  is smaller than intKey or if the table is empty
**                  and the cursor is therefore left point to nothing.
**
**     *pRes==0     The cursor is left pointing at an entry that
**                  exactly matches intKey.
**
**     *pRes>0      The cursor is left pointing at an entry that
**                  is larger than intKey.
*/
SQLITE_PRIVATE int sqlite3BtreeTableMoveto(
  BtCursor *pCur,          /* The cursor to be moved */
  i64 intKey,              /* The table key */
  int biasRight,           /* If true, bias the search to the high end */
  int *pRes                /* Write search results here */
){
  int rc;

  assert( cursorOwnsBtShared(pCur) );
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
  assert( pRes );
  assert( pCur->pKeyInfo==0 );
  assert( pCur->eState!=CURSOR_VALID || pCur->curIntKey!=0 );

  /* If the cursor is already positioned at the point we are trying
  ** to move to, then just return without doing any work */
  if( pCur->eState==CURSOR_VALID && (pCur->curFlags & BTCF_ValidNKey)!=0 ){
    if( pCur->info.nKey==intKey ){
      *pRes = 0;
      return SQLITE_OK;
    }
    if( pCur->info.nKey<intKey ){
      if( (pCur->curFlags & BTCF_AtLast)!=0 ){
        assert( cursorIsAtLastEntry(pCur) || CORRUPT_DB );
        *pRes = -1;
        return SQLITE_OK;
      }
      /* If the requested key is one more than the previous key, then
      ** try to get there using sqlite3BtreeNext() rather than a full
      ** binary search.  This is an optimization only.  The correct answer
      ** is still obtained without this case, only a little more slowly. */
      if( pCur->info.nKey+1==intKey ){
        *pRes = 0;
        rc = sqlite3BtreeNext(pCur, 0);
        if( rc==SQLITE_OK ){
          getCellInfo(pCur);
          if( pCur->info.nKey==intKey ){
            return SQLITE_OK;
          }
        }else if( rc!=SQLITE_DONE ){
          return rc;
        }
      }
    }
  }

#ifdef SQLITE_DEBUG
  pCur->pBtree->nSeek++;   /* Performance measurement during testing */
#endif

  rc = moveToRoot(pCur);
  if( rc ){
    if( rc==SQLITE_EMPTY ){
      assert( pCur->pgnoRoot==0 || pCur->pPage->nCell==0 );
      *pRes = -1;
      return SQLITE_OK;
    }
    return rc;
  }
  assert( pCur->pPage );
  assert( pCur->pPage->isInit );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->pPage->nCell > 0 );
  assert( pCur->iPage==0 || pCur->apPage[0]->intKey==pCur->curIntKey );
  assert( pCur->curIntKey );

  for(;;){
    int lwr, upr, idx, c;
    Pgno chldPg;
    MemPage *pPage = pCur->pPage;
    u8 *pCell;                          /* Pointer to current cell in pPage */

    /* pPage->nCell must be greater than zero. If this is the root-page
    ** the cursor would have been INVALID above and this for(;;) loop
    ** not run. If this is not the root-page, then the moveToChild() routine
    ** would have already detected db corruption. Similarly, pPage must
    ** be the right kind (index or table) of b-tree page. Otherwise
    ** a moveToChild() or moveToRoot() call would have detected corruption.  */
    assert( pPage->nCell>0 );
    assert( pPage->intKey );
    lwr = 0;
    upr = pPage->nCell-1;
    assert( biasRight==0 || biasRight==1 );
    idx = upr>>(1-biasRight); /* idx = biasRight ? upr : (lwr+upr)/2; */
    for(;;){
      i64 nCellKey;
      pCell = findCellPastPtr(pPage, idx);
      if( pPage->intKeyLeaf ){
        while( 0x80 <= *(pCell++) ){
          if( pCell>=pPage->aDataEnd ){
            return SQLITE_CORRUPT_PAGE(pPage);
          }
        }
      }
      getVarint(pCell, (u64*)&nCellKey);
      if( nCellKey<intKey ){
        lwr = idx+1;
        if( lwr>upr ){ c = -1; break; }
      }else if( nCellKey>intKey ){
        upr = idx-1;
        if( lwr>upr ){ c = +1; break; }
      }else{
        assert( nCellKey==intKey );
        pCur->ix = (u16)idx;
        if( !pPage->leaf ){
          lwr = idx;
          goto moveto_table_next_layer;
        }else{
          pCur->curFlags |= BTCF_ValidNKey;
          pCur->info.nKey = nCellKey;
          pCur->info.nSize = 0;
          *pRes = 0;
          return SQLITE_OK;
        }
      }
      assert( lwr+upr>=0 );
      idx = (lwr+upr)>>1;  /* idx = (lwr+upr)/2; */
    }
    assert( lwr==upr+1 || !pPage->leaf );
    assert( pPage->isInit );
    if( pPage->leaf ){
      assert( pCur->ix<pCur->pPage->nCell );
      pCur->ix = (u16)idx;
      *pRes = c;
      rc = SQLITE_OK;
      goto moveto_table_finish;
    }
moveto_table_next_layer:
    if( lwr>=pPage->nCell ){
      chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
    }else{
      chldPg = get4byte(findCell(pPage, lwr));
    }
    pCur->ix = (u16)lwr;

sqlite3.c  view on Meta::CPAN

    if( rc ) break;
  }
moveto_table_finish:
  pCur->info.nSize = 0;
  assert( (pCur->curFlags & BTCF_ValidOvfl)==0 );
  return rc;
}

/*
** Compare the "idx"-th cell on the page pPage against the key
** pointing to by pIdxKey using xRecordCompare.  Return negative or
** zero if the cell is less than or equal pIdxKey.  Return positive
** if unknown.
**
**    Return value negative:     Cell at pCur[idx] less than pIdxKey
**
**    Return value is zero:      Cell at pCur[idx] equals pIdxKey
**
**    Return value positive:     Nothing is known about the relationship
**                               of the cell at pCur[idx] and pIdxKey.
**
** This routine is part of an optimization.  It is always safe to return
** a positive value as that will cause the optimization to be skipped.
*/
static int indexCellCompare(
  MemPage *pPage,
  int idx,
  UnpackedRecord *pIdxKey,
  RecordCompare xRecordCompare
){
  int c;
  int nCell;  /* Size of the pCell cell in bytes */
  u8 *pCell = findCellPastPtr(pPage, idx);

  nCell = pCell[0];
  if( nCell<=pPage->max1bytePayload ){
    /* This branch runs if the record-size field of the cell is a
    ** single byte varint and the record fits entirely on the main
    ** b-tree page.  */
    testcase( pCell+nCell+1==pPage->aDataEnd );
    c = xRecordCompare(nCell, (void*)&pCell[1], pIdxKey);
  }else if( !(pCell[1] & 0x80)
    && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
  ){
    /* The record-size field is a 2 byte varint and the record
    ** fits entirely on the main b-tree page.  */
    testcase( pCell+nCell+2==pPage->aDataEnd );
    c = xRecordCompare(nCell, (void*)&pCell[2], pIdxKey);
  }else{
    /* If the record extends into overflow pages, do not attempt
    ** the optimization. */
    c = 99;
  }
  return c;
}

/*
** Return true (non-zero) if pCur is current pointing to the last
** page of a table.
*/
static int cursorOnLastPage(BtCursor *pCur){
  int i;
  assert( pCur->eState==CURSOR_VALID );
  for(i=0; i<pCur->iPage; i++){
    MemPage *pPage = pCur->apPage[i];
    if( pCur->aiIdx[i]<pPage->nCell ) return 0;
  }
  return 1;
}

/* Move the cursor so that it points to an entry in an index table
** near the key pIdxKey.   Return a success code.
**
** If an exact match is not found, then the cursor is always
** left pointing at a leaf page which would hold the entry if it
** were present.  The cursor might point to an entry that comes
** before or after the key.
**
** An integer is written into *pRes which is the result of
** comparing the key with the entry to which the cursor is
** pointing.  The meaning of the integer written into
** *pRes is as follows:
**
**     *pRes<0      The cursor is left pointing at an entry that
**                  is smaller than pIdxKey or if the table is empty
**                  and the cursor is therefore left point to nothing.
**
**     *pRes==0     The cursor is left pointing at an entry that
**                  exactly matches pIdxKey.
**
**     *pRes>0      The cursor is left pointing at an entry that
**                  is larger than pIdxKey.
**
** The pIdxKey->eqSeen field is set to 1 if there
** exists an entry in the table that exactly matches pIdxKey.
*/
SQLITE_PRIVATE int sqlite3BtreeIndexMoveto(
  BtCursor *pCur,          /* The cursor to be moved */
  UnpackedRecord *pIdxKey, /* Unpacked index key */
  int *pRes                /* Write search results here */
){
  int rc;
  RecordCompare xRecordCompare;

  assert( cursorOwnsBtShared(pCur) );
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );
  assert( pRes );
  assert( pCur->pKeyInfo!=0 );

#ifdef SQLITE_DEBUG
  pCur->pBtree->nSeek++;   /* Performance measurement during testing */
#endif

  xRecordCompare = sqlite3VdbeFindCompare(pIdxKey);
  pIdxKey->errCode = 0;
  assert( pIdxKey->default_rc==1
       || pIdxKey->default_rc==0
       || pIdxKey->default_rc==-1
  );


  /* Check to see if we can skip a lot of work.  Two cases:
  **
  **    (1) If the cursor is already pointing to the very last cell
  **        in the table and the pIdxKey search key is greater than or
  **        equal to that last cell, then no movement is required.
  **
  **    (2) If the cursor is on the last page of the table and the first
  **        cell on that last page is less than or equal to the pIdxKey
  **        search key, then we can start the search on the current page
  **        without needing to go back to root.
  */
  if( pCur->eState==CURSOR_VALID
   && pCur->pPage->leaf
   && cursorOnLastPage(pCur)
  ){
    int c;
    if( pCur->ix==pCur->pPage->nCell-1
     && (c = indexCellCompare(pCur->pPage,pCur->ix,pIdxKey,xRecordCompare))<=0
     && pIdxKey->errCode==SQLITE_OK
    ){
      *pRes = c;
      return SQLITE_OK;  /* Cursor already pointing at the correct spot */
    }
    if( pCur->iPage>0
     && indexCellCompare(pCur->pPage, 0, pIdxKey, xRecordCompare)<=0
     && pIdxKey->errCode==SQLITE_OK
    ){
      pCur->curFlags &= ~(BTCF_ValidOvfl|BTCF_AtLast);
      if( !pCur->pPage->isInit ){
        return SQLITE_CORRUPT_BKPT;
      }
      goto bypass_moveto_root;  /* Start search on the current page */
    }
    pIdxKey->errCode = SQLITE_OK;
  }

  rc = moveToRoot(pCur);
  if( rc ){
    if( rc==SQLITE_EMPTY ){
      assert( pCur->pgnoRoot==0 || pCur->pPage->nCell==0 );
      *pRes = -1;
      return SQLITE_OK;
    }
    return rc;
  }

bypass_moveto_root:
  assert( pCur->pPage );
  assert( pCur->pPage->isInit );
  assert( pCur->eState==CURSOR_VALID );
  assert( pCur->pPage->nCell > 0 );
  assert( pCur->curIntKey==0 );
  assert( pIdxKey!=0 );
  for(;;){
    int lwr, upr, idx, c;
    Pgno chldPg;
    MemPage *pPage = pCur->pPage;
    u8 *pCell;                          /* Pointer to current cell in pPage */

    /* pPage->nCell must be greater than zero. If this is the root-page
    ** the cursor would have been INVALID above and this for(;;) loop
    ** not run. If this is not the root-page, then the moveToChild() routine
    ** would have already detected db corruption. Similarly, pPage must
    ** be the right kind (index or table) of b-tree page. Otherwise
    ** a moveToChild() or moveToRoot() call would have detected corruption.  */
    assert( pPage->nCell>0 );
    assert( pPage->intKey==0 );
    lwr = 0;
    upr = pPage->nCell-1;
    idx = upr>>1; /* idx = (lwr+upr)/2; */
    for(;;){
      int nCell;  /* Size of the pCell cell in bytes */
      pCell = findCellPastPtr(pPage, idx);

      /* The maximum supported page-size is 65536 bytes. This means that
      ** the maximum number of record bytes stored on an index B-Tree
      ** page is less than 16384 bytes and may be stored as a 2-byte
      ** varint. This information is used to attempt to avoid parsing
      ** the entire cell by checking for the cases where the record is
      ** stored entirely within the b-tree page by inspecting the first
      ** 2 bytes of the cell.
      */
      nCell = pCell[0];
      if( nCell<=pPage->max1bytePayload ){
        /* This branch runs if the record-size field of the cell is a
        ** single byte varint and the record fits entirely on the main
        ** b-tree page.  */
        testcase( pCell+nCell+1==pPage->aDataEnd );
        c = xRecordCompare(nCell, (void*)&pCell[1], pIdxKey);
      }else if( !(pCell[1] & 0x80)
        && (nCell = ((nCell&0x7f)<<7) + pCell[1])<=pPage->maxLocal
      ){
        /* The record-size field is a 2 byte varint and the record
        ** fits entirely on the main b-tree page.  */
        testcase( pCell+nCell+2==pPage->aDataEnd );
        c = xRecordCompare(nCell, (void*)&pCell[2], pIdxKey);
      }else{
        /* The record flows over onto one or more overflow pages. In
        ** this case the whole cell needs to be parsed, a buffer allocated
        ** and accessPayload() used to retrieve the record into the
        ** buffer before VdbeRecordCompare() can be called.
        **
        ** If the record is corrupt, the xRecordCompare routine may read
        ** up to two varints past the end of the buffer. An extra 18
        ** bytes of padding is allocated at the end of the buffer in
        ** case this happens.  */
        void *pCellKey;
        u8 * const pCellBody = pCell - pPage->childPtrSize;
        const int nOverrun = 18;  /* Size of the overrun padding */
        pPage->xParseCell(pPage, pCellBody, &pCur->info);
        nCell = (int)pCur->info.nKey;
        testcase( nCell<0 );   /* True if key size is 2^32 or more */
        testcase( nCell==0 );  /* Invalid key size:  0x80 0x80 0x00 */
        testcase( nCell==1 );  /* Invalid key size:  0x80 0x80 0x01 */
        testcase( nCell==2 );  /* Minimum legal index key size */
        if( nCell<2 || nCell/pCur->pBt->usableSize>pCur->pBt->nPage ){
          rc = SQLITE_CORRUPT_PAGE(pPage);
          goto moveto_index_finish;
        }
        pCellKey = sqlite3Malloc( (u64)nCell+(u64)nOverrun );
        if( pCellKey==0 ){

sqlite3.c  view on Meta::CPAN

        pCur->ix = (u16)idx;
        if( pIdxKey->errCode ) rc = SQLITE_CORRUPT_BKPT;
        goto moveto_index_finish;
      }
      if( lwr>upr ) break;
      assert( lwr+upr>=0 );
      idx = (lwr+upr)>>1;  /* idx = (lwr+upr)/2 */
    }
    assert( lwr==upr+1 || (pPage->intKey && !pPage->leaf) );
    assert( pPage->isInit );
    if( pPage->leaf ){
      assert( pCur->ix<pCur->pPage->nCell || CORRUPT_DB );
      pCur->ix = (u16)idx;
      *pRes = c;
      rc = SQLITE_OK;
      goto moveto_index_finish;
    }
    if( lwr>=pPage->nCell ){
      chldPg = get4byte(&pPage->aData[pPage->hdrOffset+8]);
    }else{
      chldPg = get4byte(findCell(pPage, lwr));
    }

    /* This block is similar to an in-lined version of:
    **
    **    pCur->ix = (u16)lwr;
    **    rc = moveToChild(pCur, chldPg);
    **    if( rc ) break;
    */
    pCur->info.nSize = 0;
    pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
    if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
      return SQLITE_CORRUPT_BKPT;
    }
    pCur->aiIdx[pCur->iPage] = (u16)lwr;
    pCur->apPage[pCur->iPage] = pCur->pPage;
    pCur->ix = 0;
    pCur->iPage++;
    rc = getAndInitPage(pCur->pBt, chldPg, &pCur->pPage, pCur->curPagerFlags);
    if( rc==SQLITE_OK
     && (pCur->pPage->nCell<1 || pCur->pPage->intKey!=pCur->curIntKey)
    ){
      releasePage(pCur->pPage);
      rc = SQLITE_CORRUPT_PGNO(chldPg);
    }
    if( rc ){
      pCur->pPage = pCur->apPage[--pCur->iPage];
      break;
    }
    /*
    ***** End of in-lined moveToChild() call */
 }
moveto_index_finish:
  pCur->info.nSize = 0;
  assert( (pCur->curFlags & BTCF_ValidOvfl)==0 );
  return rc;
}


/*
** Return TRUE if the cursor is not pointing at an entry of the table.
**
** TRUE will be returned after a call to sqlite3BtreeNext() moves
** past the last entry in the table or sqlite3BtreePrev() moves past
** the first entry.  TRUE is also returned if the table is empty.
*/
SQLITE_PRIVATE int sqlite3BtreeEof(BtCursor *pCur){
  /* TODO: What if the cursor is in CURSOR_REQUIRESEEK but all table entries
  ** have been deleted? This API will need to change to return an error code
  ** as well as the boolean result value.
  */
  return (CURSOR_VALID!=pCur->eState);
}

/*
** Return an estimate for the number of rows in the table that pCur is
** pointing to.  Return a negative number if no estimate is currently
** available.
*/
SQLITE_PRIVATE i64 sqlite3BtreeRowCountEst(BtCursor *pCur){
  i64 n;
  u8 i;

  assert( cursorOwnsBtShared(pCur) );
  assert( sqlite3_mutex_held(pCur->pBtree->db->mutex) );

  /* Currently this interface is only called by the OP_IfSizeBetween
  ** opcode and the OP_Count opcode with P3=1.  In either case,
  ** the cursor will always be valid unless the btree is empty. */
  if( pCur->eState!=CURSOR_VALID ) return 0;
  if( NEVER(pCur->pPage->leaf==0) ) return -1;

  n = pCur->pPage->nCell;
  for(i=0; i<pCur->iPage; i++){
    n *= pCur->apPage[i]->nCell+1;
  }
  return n;
}

/*
** Advance the cursor to the next entry in the database.
** Return value:
**
**    SQLITE_OK        success
**    SQLITE_DONE      cursor is already pointing at the last element
**    otherwise        some kind of error occurred
**
** The main entry point is sqlite3BtreeNext().  That routine is optimized
** for the common case of merely incrementing the cell counter BtCursor.aiIdx
** to the next cell on the current page.  The (slower) btreeNext() helper
** routine is called when it is necessary to move to a different page or
** to restore the cursor.
**
** If bit 0x01 of the F argument in sqlite3BtreeNext(C,F) is 1, then the
** cursor corresponds to an SQL index and this routine could have been
** skipped if the SQL index had been a unique index.  The F argument
** is a hint to the implement.  SQLite btree implementation does not use
** this hint, but COMDB2 does.
*/
static SQLITE_NOINLINE int btreeNext(BtCursor *pCur){
  int rc;
  int idx;
  MemPage *pPage;

  assert( cursorOwnsBtShared(pCur) );
  if( pCur->eState!=CURSOR_VALID ){
    assert( (pCur->curFlags & BTCF_ValidOvfl)==0 );
    rc = restoreCursorPosition(pCur);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    if( CURSOR_INVALID==pCur->eState ){
      return SQLITE_DONE;
    }
    if( pCur->eState==CURSOR_SKIPNEXT ){
      pCur->eState = CURSOR_VALID;
      if( pCur->skipNext>0 ) return SQLITE_OK;
    }
  }

  pPage = pCur->pPage;
  idx = ++pCur->ix;
  if( sqlite3FaultSim(412) ) pPage->isInit = 0;
  if( !pPage->isInit ){
    return SQLITE_CORRUPT_BKPT;
  }

  if( idx>=pPage->nCell ){
    if( !pPage->leaf ){
      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
      if( rc ) return rc;
      return moveToLeftmost(pCur);
    }
    do{
      if( pCur->iPage==0 ){
        pCur->eState = CURSOR_INVALID;
        return SQLITE_DONE;
      }
      moveToParent(pCur);
      pPage = pCur->pPage;
    }while( pCur->ix>=pPage->nCell );
    if( pPage->intKey ){
      return sqlite3BtreeNext(pCur, 0);
    }else{
      return SQLITE_OK;
    }
  }
  if( pPage->leaf ){
    return SQLITE_OK;
  }else{
    return moveToLeftmost(pCur);
  }
}
SQLITE_PRIVATE int sqlite3BtreeNext(BtCursor *pCur, int flags){
  MemPage *pPage;
  UNUSED_PARAMETER( flags );  /* Used in COMDB2 but not native SQLite */
  assert( cursorOwnsBtShared(pCur) );
  assert( flags==0 || flags==1 );
  pCur->info.nSize = 0;
  pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
  if( pCur->eState!=CURSOR_VALID ) return btreeNext(pCur);
  pPage = pCur->pPage;
  if( (++pCur->ix)>=pPage->nCell ){
    pCur->ix--;
    return btreeNext(pCur);
  }
  if( pPage->leaf ){
    return SQLITE_OK;
  }else{
    return moveToLeftmost(pCur);
  }
}

/*
** Step the cursor to the back to the previous entry in the database.
** Return values:
**
**     SQLITE_OK     success
**     SQLITE_DONE   the cursor is already on the first element of the table
**     otherwise     some kind of error occurred
**
** The main entry point is sqlite3BtreePrevious().  That routine is optimized
** for the common case of merely decrementing the cell counter BtCursor.aiIdx
** to the previous cell on the current page.  The (slower) btreePrevious()
** helper routine is called when it is necessary to move to a different page
** or to restore the cursor.
**
** If bit 0x01 of the F argument to sqlite3BtreePrevious(C,F) is 1, then
** the cursor corresponds to an SQL index and this routine could have been
** skipped if the SQL index had been a unique index.  The F argument is a
** hint to the implement.  The native SQLite btree implementation does not
** use this hint, but COMDB2 does.
*/
static SQLITE_NOINLINE int btreePrevious(BtCursor *pCur){
  int rc;
  MemPage *pPage;

  assert( cursorOwnsBtShared(pCur) );
  assert( (pCur->curFlags & (BTCF_AtLast|BTCF_ValidOvfl|BTCF_ValidNKey))==0 );
  assert( pCur->info.nSize==0 );
  if( pCur->eState!=CURSOR_VALID ){
    rc = restoreCursorPosition(pCur);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    if( CURSOR_INVALID==pCur->eState ){
      return SQLITE_DONE;
    }
    if( CURSOR_SKIPNEXT==pCur->eState ){
      pCur->eState = CURSOR_VALID;
      if( pCur->skipNext<0 ) return SQLITE_OK;
    }
  }

  pPage = pCur->pPage;
  if( sqlite3FaultSim(412) ) pPage->isInit = 0;
  if( !pPage->isInit ){
    return SQLITE_CORRUPT_BKPT;
  }
  if( !pPage->leaf ){
    int idx = pCur->ix;
    rc = moveToChild(pCur, get4byte(findCell(pPage, idx)));
    if( rc ) return rc;
    rc = moveToRightmost(pCur);
  }else{
    while( pCur->ix==0 ){
      if( pCur->iPage==0 ){
        pCur->eState = CURSOR_INVALID;
        return SQLITE_DONE;
      }
      moveToParent(pCur);
    }
    assert( pCur->info.nSize==0 );
    assert( (pCur->curFlags & (BTCF_ValidOvfl))==0 );

    pCur->ix--;
    pPage = pCur->pPage;
    if( pPage->intKey && !pPage->leaf ){
      rc = sqlite3BtreePrevious(pCur, 0);
    }else{
      rc = SQLITE_OK;
    }
  }
  return rc;
}
SQLITE_PRIVATE int sqlite3BtreePrevious(BtCursor *pCur, int flags){
  assert( cursorOwnsBtShared(pCur) );
  assert( flags==0 || flags==1 );
  UNUSED_PARAMETER( flags );  /* Used in COMDB2 but not native SQLite */
  pCur->curFlags &= ~(BTCF_AtLast|BTCF_ValidOvfl|BTCF_ValidNKey);
  pCur->info.nSize = 0;
  if( pCur->eState!=CURSOR_VALID
   || pCur->ix==0
   || pCur->pPage->leaf==0
  ){
    return btreePrevious(pCur);
  }
  pCur->ix--;
  return SQLITE_OK;
}

/*
** Allocate a new page from the database file.
**
** The new page is marked as dirty.  (In other words, sqlite3PagerWrite()
** has already been called on the new page.)  The new page has also
** been referenced and the calling routine is responsible for calling
** sqlite3PagerUnref() on the new page when it is done.
**
** SQLITE_OK is returned on success.  Any other return value indicates
** an error.  *ppPage is set to NULL in the event of an error.
**
** If the "nearby" parameter is not 0, then an effort is made to
** locate a page close to the page number "nearby".  This can be used in an
** attempt to keep related pages close to each other in the database file,
** which in turn can make database access faster.
**
** If the eMode parameter is BTALLOC_EXACT and the nearby page exists
** anywhere on the free-list, then it is guaranteed to be returned.  If
** eMode is BTALLOC_LT then the page returned will be less than or equal
** to nearby if any such page exists.  If eMode is BTALLOC_ANY then there
** are no restrictions on which page is returned.
*/
static int allocateBtreePage(
  BtShared *pBt,         /* The btree */
  MemPage **ppPage,      /* Store pointer to the allocated page here */
  Pgno *pPgno,           /* Store the page number here */
  Pgno nearby,           /* Search for a page near this one */
  u8 eMode               /* BTALLOC_EXACT, BTALLOC_LT, or BTALLOC_ANY */
){
  MemPage *pPage1;
  int rc;
  u32 n;     /* Number of pages on the freelist */
  u32 k;     /* Number of leaves on the trunk of the freelist */
  MemPage *pTrunk = 0;
  MemPage *pPrevTrunk = 0;
  Pgno mxPage;     /* Total size of the database file */

  assert( sqlite3_mutex_held(pBt->mutex) );
  assert( eMode==BTALLOC_ANY || (nearby>0 && IfNotOmitAV(pBt->autoVacuum)) );
  pPage1 = pBt->pPage1;
  mxPage = btreePagecount(pBt);
  /* EVIDENCE-OF: R-21003-45125 The 4-byte big-endian integer at offset 36
  ** stores the total number of pages on the freelist. */
  n = get4byte(&pPage1->aData[36]);
  testcase( n==mxPage-1 );
  if( n>=mxPage ){

sqlite3.c  view on Meta::CPAN

  if( pPage ){
    pPage->isInit = 0;
  }
  releasePage(pPage);
  releasePage(pTrunk);
  return rc;
}
static void freePage(MemPage *pPage, int *pRC){
  if( (*pRC)==SQLITE_OK ){
    *pRC = freePage2(pPage->pBt, pPage, pPage->pgno);
  }
}

/*
** Free the overflow pages associated with the given Cell.
*/
static SQLITE_NOINLINE int clearCellOverflow(
  MemPage *pPage,          /* The page that contains the Cell */
  unsigned char *pCell,    /* First byte of the Cell */
  CellInfo *pInfo          /* Size information about the cell */
){
  BtShared *pBt;
  Pgno ovflPgno;
  int rc;
  int nOvfl;
  u32 ovflPageSize;

  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( pInfo->nLocal!=pInfo->nPayload );
  testcase( pCell + pInfo->nSize == pPage->aDataEnd );
  testcase( pCell + (pInfo->nSize-1) == pPage->aDataEnd );
  if( pCell + pInfo->nSize > pPage->aDataEnd ){
    /* Cell extends past end of page */
    return SQLITE_CORRUPT_PAGE(pPage);
  }
  ovflPgno = get4byte(pCell + pInfo->nSize - 4);
  pBt = pPage->pBt;
  assert( pBt->usableSize > 4 );
  ovflPageSize = pBt->usableSize - 4;
  nOvfl = (pInfo->nPayload - pInfo->nLocal + ovflPageSize - 1)/ovflPageSize;
  assert( nOvfl>0 ||
    (CORRUPT_DB && (pInfo->nPayload + ovflPageSize)<ovflPageSize)
  );
  while( nOvfl-- ){
    Pgno iNext = 0;
    MemPage *pOvfl = 0;
    if( ovflPgno<2 || ovflPgno>btreePagecount(pBt) ){
      /* 0 is not a legal page number and page 1 cannot be an
      ** overflow page. Therefore if ovflPgno<2 or past the end of the
      ** file the database must be corrupt. */
      return SQLITE_CORRUPT_BKPT;
    }
    if( nOvfl ){
      rc = getOverflowPage(pBt, ovflPgno, &pOvfl, &iNext);
      if( rc ) return rc;
    }

    if( ( pOvfl || ((pOvfl = btreePageLookup(pBt, ovflPgno))!=0) )
     && sqlite3PagerPageRefcount(pOvfl->pDbPage)!=1
    ){
      /* There is no reason any cursor should have an outstanding reference
      ** to an overflow page belonging to a cell that is being deleted/updated.
      ** So if there exists more than one reference to this page, then it
      ** must not really be an overflow page and the database must be corrupt.
      ** It is helpful to detect this before calling freePage2(), as
      ** freePage2() may zero the page contents if secure-delete mode is
      ** enabled. If this 'overflow' page happens to be a page that the
      ** caller is iterating through or using in some other way, this
      ** can be problematic.
      */
      rc = SQLITE_CORRUPT_BKPT;
    }else{
      rc = freePage2(pBt, pOvfl, ovflPgno);
    }

    if( pOvfl ){
      sqlite3PagerUnref(pOvfl->pDbPage);
    }
    if( rc ) return rc;
    ovflPgno = iNext;
  }
  return SQLITE_OK;
}

/* Call xParseCell to compute the size of a cell.  If the cell contains
** overflow, then invoke cellClearOverflow to clear out that overflow.
** Store the result code (SQLITE_OK or some error code) in rc.
**
** Implemented as macro to force inlining for performance.
*/
#define BTREE_CLEAR_CELL(rc, pPage, pCell, sInfo)   \
  pPage->xParseCell(pPage, pCell, &sInfo);          \
  if( sInfo.nLocal!=sInfo.nPayload ){               \
    rc = clearCellOverflow(pPage, pCell, &sInfo);   \
  }else{                                            \
    rc = SQLITE_OK;                                 \
  }


/*
** Create the byte sequence used to represent a cell on page pPage
** and write that byte sequence into pCell[].  Overflow pages are
** allocated and filled in as necessary.  The calling procedure
** is responsible for making sure sufficient space has been allocated
** for pCell[].
**
** Note that pCell does not necessary need to point to the pPage->aData
** area.  pCell might point to some temporary storage.  The cell will
** be constructed in this temporary area then copied into pPage->aData
** later.
*/
static int fillInCell(
  MemPage *pPage,                /* The page that contains the cell */
  unsigned char *pCell,          /* Complete text of the cell */
  const BtreePayload *pX,        /* Payload with which to construct the cell */
  int *pnSize                    /* Write cell size here */
){
  int nPayload;
  const u8 *pSrc;
  int nSrc, n, rc, mn;
  int spaceLeft;

sqlite3.c  view on Meta::CPAN

** pointer pointing to the new page.
**
** Before returning, all pointer-map entries corresponding to pages
** that the new child-page now contains pointers to are updated. The
** entry corresponding to the new right-child pointer of the root
** page is also updated.
**
** If successful, *ppChild is set to contain a reference to the child
** page and SQLITE_OK is returned. In this case the caller is required
** to call releasePage() on *ppChild exactly once. If an error occurs,
** an error code is returned and *ppChild is set to 0.
*/
static int balance_deeper(MemPage *pRoot, MemPage **ppChild){
  int rc;                        /* Return value from subprocedures */
  MemPage *pChild = 0;           /* Pointer to a new child page */
  Pgno pgnoChild = 0;            /* Page number of the new child page */
  BtShared *pBt = pRoot->pBt;    /* The BTree */

  assert( pRoot->nOverflow>0 );
  assert( sqlite3_mutex_held(pBt->mutex) );

  /* Make pRoot, the root page of the b-tree, writable. Allocate a new
  ** page that will become the new right-child of pPage. Copy the contents
  ** of the node stored on pRoot into the new child page.
  */
  rc = sqlite3PagerWrite(pRoot->pDbPage);
  if( rc==SQLITE_OK ){
    rc = allocateBtreePage(pBt,&pChild,&pgnoChild,pRoot->pgno,0);
    copyNodeContent(pRoot, pChild, &rc);
    if( ISAUTOVACUUM(pBt) ){
      ptrmapPut(pBt, pgnoChild, PTRMAP_BTREE, pRoot->pgno, &rc);
    }
  }
  if( rc ){
    *ppChild = 0;
    releasePage(pChild);
    return rc;
  }
  assert( sqlite3PagerIswriteable(pChild->pDbPage) );
  assert( sqlite3PagerIswriteable(pRoot->pDbPage) );
  assert( pChild->nCell==pRoot->nCell || CORRUPT_DB );

  TRACE(("BALANCE: copy root %u into %u\n", pRoot->pgno, pChild->pgno));

  /* Copy the overflow cells from pRoot to pChild */
  memcpy(pChild->aiOvfl, pRoot->aiOvfl,
         pRoot->nOverflow*sizeof(pRoot->aiOvfl[0]));
  memcpy(pChild->apOvfl, pRoot->apOvfl,
         pRoot->nOverflow*sizeof(pRoot->apOvfl[0]));
  pChild->nOverflow = pRoot->nOverflow;

  /* Zero the contents of pRoot. Then install pChild as the right-child. */
  zeroPage(pRoot, pChild->aData[0] & ~PTF_LEAF);
  put4byte(&pRoot->aData[pRoot->hdrOffset+8], pgnoChild);

  *ppChild = pChild;
  return SQLITE_OK;
}

/*
** Return SQLITE_CORRUPT if any cursor other than pCur is currently valid
** on the same B-tree as pCur.
**
** This can occur if a database is corrupt with two or more SQL tables
** pointing to the same b-tree.  If an insert occurs on one SQL table
** and causes a BEFORE TRIGGER to do a secondary insert on the other SQL
** table linked to the same b-tree.  If the secondary insert causes a
** rebalance, that can change content out from under the cursor on the
** first SQL table, violating invariants on the first insert.
*/
static int anotherValidCursor(BtCursor *pCur){
  BtCursor *pOther;
  for(pOther=pCur->pBt->pCursor; pOther; pOther=pOther->pNext){
    if( pOther!=pCur
     && pOther->eState==CURSOR_VALID
     && pOther->pPage==pCur->pPage
    ){
      return SQLITE_CORRUPT_PAGE(pCur->pPage);
    }
  }
  return SQLITE_OK;
}

/*
** The page that pCur currently points to has just been modified in
** some way. This function figures out if this modification means the
** tree needs to be balanced, and if so calls the appropriate balancing
** routine. Balancing routines are:
**
**   balance_quick()
**   balance_deeper()
**   balance_nonroot()
*/
static int balance(BtCursor *pCur){
  int rc = SQLITE_OK;
  u8 aBalanceQuickSpace[13];
  u8 *pFree = 0;

  VVA_ONLY( int balance_quick_called = 0 );
  VVA_ONLY( int balance_deeper_called = 0 );

  do {
    int iPage;
    MemPage *pPage = pCur->pPage;

    if( NEVER(pPage->nFree<0) && btreeComputeFreeSpace(pPage) ) break;
    if( pPage->nOverflow==0 && pPage->nFree*3<=(int)pCur->pBt->usableSize*2 ){
      /* No rebalance required as long as:
      **   (1) There are no overflow cells
      **   (2) The amount of free space on the page is less than 2/3rds of
      **       the total usable space on the page. */
      break;
    }else if( (iPage = pCur->iPage)==0 ){
      if( pPage->nOverflow && (rc = anotherValidCursor(pCur))==SQLITE_OK ){
        /* The root page of the b-tree is overfull. In this case call the
        ** balance_deeper() function to create a new child for the root-page
        ** and copy the current contents of the root-page to it. The
        ** next iteration of the do-loop will balance the child page.
        */
        assert( balance_deeper_called==0 );
        VVA_ONLY( balance_deeper_called++ );
        rc = balance_deeper(pPage, &pCur->apPage[1]);
        if( rc==SQLITE_OK ){
          pCur->iPage = 1;
          pCur->ix = 0;
          pCur->aiIdx[0] = 0;
          pCur->apPage[0] = pPage;
          pCur->pPage = pCur->apPage[1];

sqlite3.c  view on Meta::CPAN


      pPage->nOverflow = 0;

      /* The next iteration of the do-loop balances the parent page. */
      releasePage(pPage);
      pCur->iPage--;
      assert( pCur->iPage>=0 );
      pCur->pPage = pCur->apPage[pCur->iPage];
    }
  }while( rc==SQLITE_OK );

  if( pFree ){
    sqlite3PageFree(pFree);
  }
  return rc;
}

/* Overwrite content from pX into pDest.  Only do the write if the
** content is different from what is already there.
*/
static int btreeOverwriteContent(
  MemPage *pPage,           /* MemPage on which writing will occur */
  u8 *pDest,                /* Pointer to the place to start writing */
  const BtreePayload *pX,   /* Source of data to write */
  int iOffset,              /* Offset of first byte to write */
  int iAmt                  /* Number of bytes to be written */
){
  int nData = pX->nData - iOffset;
  if( nData<=0 ){
    /* Overwriting with zeros */
    int i;
    for(i=0; i<iAmt && pDest[i]==0; i++){}
    if( i<iAmt ){
      int rc = sqlite3PagerWrite(pPage->pDbPage);
      if( rc ) return rc;
      memset(pDest + i, 0, iAmt - i);
    }
  }else{
    if( nData<iAmt ){
      /* Mixed read data and zeros at the end.  Make a recursive call
      ** to write the zeros then fall through to write the real data */
      int rc = btreeOverwriteContent(pPage, pDest+nData, pX, iOffset+nData,
                                 iAmt-nData);
      if( rc ) return rc;
      iAmt = nData;
    }
    if( memcmp(pDest, ((u8*)pX->pData) + iOffset, iAmt)!=0 ){
      int rc = sqlite3PagerWrite(pPage->pDbPage);
      if( rc ) return rc;
      /* In a corrupt database, it is possible for the source and destination
      ** buffers to overlap.  This is harmless since the database is already
      ** corrupt but it does cause valgrind and ASAN warnings.  So use
      ** memmove(). */
      memmove(pDest, ((u8*)pX->pData) + iOffset, iAmt);
    }
  }
  return SQLITE_OK;
}

/*
** Overwrite the cell that cursor pCur is pointing to with fresh content
** contained in pX.  In this variant, pCur is pointing to an overflow
** cell.
*/
static SQLITE_NOINLINE int btreeOverwriteOverflowCell(
  BtCursor *pCur,                     /* Cursor pointing to cell to overwrite */
  const BtreePayload *pX              /* Content to write into the cell */
){
  int iOffset;                        /* Next byte of pX->pData to write */
  int nTotal = pX->nData + pX->nZero; /* Total bytes of to write */
  int rc;                             /* Return code */
  MemPage *pPage = pCur->pPage;       /* Page being written */
  BtShared *pBt;                      /* Btree */
  Pgno ovflPgno;                      /* Next overflow page to write */
  u32 ovflPageSize;                   /* Size to write on overflow page */

  assert( pCur->info.nLocal<nTotal );  /* pCur is an overflow cell */

  /* Overwrite the local portion first */
  rc = btreeOverwriteContent(pPage, pCur->info.pPayload, pX,
                             0, pCur->info.nLocal);
  if( rc ) return rc;

  /* Now overwrite the overflow pages */
  iOffset = pCur->info.nLocal;
  assert( nTotal>=0 );
  assert( iOffset>=0 );
  ovflPgno = get4byte(pCur->info.pPayload + iOffset);
  pBt = pPage->pBt;
  ovflPageSize = pBt->usableSize - 4;
  do{
    rc = btreeGetPage(pBt, ovflPgno, &pPage, 0);
    if( rc ) return rc;
    if( sqlite3PagerPageRefcount(pPage->pDbPage)!=1 || pPage->isInit ){
      rc = SQLITE_CORRUPT_PAGE(pPage);
    }else{
      if( iOffset+ovflPageSize<(u32)nTotal ){
        ovflPgno = get4byte(pPage->aData);
      }else{
        ovflPageSize = nTotal - iOffset;
      }
      rc = btreeOverwriteContent(pPage, pPage->aData+4, pX,
                                 iOffset, ovflPageSize);
    }
    sqlite3PagerUnref(pPage->pDbPage);
    if( rc ) return rc;
    iOffset += ovflPageSize;
  }while( iOffset<nTotal );
  return SQLITE_OK;
}

/*
** Overwrite the cell that cursor pCur is pointing to with fresh content
** contained in pX.
*/
static int btreeOverwriteCell(BtCursor *pCur, const BtreePayload *pX){
  int nTotal = pX->nData + pX->nZero; /* Total bytes of to write */
  MemPage *pPage = pCur->pPage;       /* Page being written */

  if( pCur->info.pPayload + pCur->info.nLocal > pPage->aDataEnd
   || pCur->info.pPayload < pPage->aData + pPage->cellOffset
  ){
    return SQLITE_CORRUPT_PAGE(pPage);
  }
  if( pCur->info.nLocal==nTotal ){
    /* The entire cell is local */
    return btreeOverwriteContent(pPage, pCur->info.pPayload, pX,
                                 0, pCur->info.nLocal);
  }else{
    /* The cell contains overflow content */
    return btreeOverwriteOverflowCell(pCur, pX);
  }
}


/*
** Insert a new record into the BTree.  The content of the new record
** is described by the pX object.  The pCur cursor is used only to
** define what table the record should be inserted into, and is left
** pointing at a random location.
**
** For a table btree (used for rowid tables), only the pX.nKey value of
** the key is used. The pX.pKey value must be NULL.  The pX.nKey is the
** rowid or INTEGER PRIMARY KEY of the row.  The pX.nData,pData,nZero fields
** hold the content of the row.
**
** For an index btree (used for indexes and WITHOUT ROWID tables), the
** key is an arbitrary byte sequence stored in pX.pKey,nKey.  The
** pX.pData,nData,nZero fields must be zero.
**
** If the seekResult parameter is non-zero, then a successful call to
** sqlite3BtreeIndexMoveto() to seek cursor pCur to (pKey,nKey) has already
** been performed.  In other words, if seekResult!=0 then the cursor
** is currently pointing to a cell that will be adjacent to the cell
** to be inserted.  If seekResult<0 then pCur points to a cell that is
** smaller then (pKey,nKey).  If seekResult>0 then pCur points to a cell
** that is larger than (pKey,nKey).
**
** If seekResult==0, that means pCur is pointing at some unknown location.
** In that case, this routine must seek the cursor to the correct insertion
** point for (pKey,nKey) before doing the insertion.  For index btrees,
** if pX->nMem is non-zero, then pX->aMem contains pointers to the unpacked
** key values and pX->aMem can be used instead of pX->pKey to avoid having
** to decode the key.
*/
SQLITE_PRIVATE int sqlite3BtreeInsert(
  BtCursor *pCur,                /* Insert data into the table of this cursor */
  const BtreePayload *pX,        /* Content of the row to be inserted */
  int flags,                     /* True if this is likely an append */
  int seekResult                 /* Result of prior IndexMoveto() call */
){
  int rc;
  int loc = seekResult;          /* -1: before desired location  +1: after */
  int szNew = 0;
  int idx;
  MemPage *pPage;
  Btree *p = pCur->pBtree;
  unsigned char *oldCell;
  unsigned char *newCell = 0;

  assert( (flags & (BTREE_SAVEPOSITION|BTREE_APPEND|BTREE_PREFORMAT))==flags );
  assert( (flags & BTREE_PREFORMAT)==0 || seekResult || pCur->pKeyInfo==0 );

  /* Save the positions of any other cursors open on this table.
  **
  ** In some cases, the call to btreeMoveto() below is a no-op. For
  ** example, when inserting data into a table with auto-generated integer
  ** keys, the VDBE layer invokes sqlite3BtreeLast() to figure out the
  ** integer key to use. It then calls this function to actually insert the
  ** data into the intkey B-Tree. In this case btreeMoveto() recognizes
  ** that the cursor is already where it needs to be and returns without
  ** doing any work. To avoid thwarting these optimizations, it is important
  ** not to clear the cursor here.
  */
  if( pCur->curFlags & BTCF_Multiple ){
    rc = saveAllCursors(p->pBt, pCur->pgnoRoot, pCur);
    if( rc ) return rc;
    if( loc && pCur->iPage<0 ){
      /* This can only happen if the schema is corrupt such that there is more
      ** than one table or index with the same root page as used by the cursor.
      ** Which can only happen if the SQLITE_NoSchemaError flag was set when
      ** the schema was loaded. This cannot be asserted though, as a user might
      ** set the flag, load the schema, and then unset the flag.  */
      return SQLITE_CORRUPT_PGNO(pCur->pgnoRoot);
    }
  }

  /* Ensure that the cursor is not in the CURSOR_FAULT state and that it
  ** points to a valid cell.
  */
  if( pCur->eState>=CURSOR_REQUIRESEEK ){
    testcase( pCur->eState==CURSOR_REQUIRESEEK );
    testcase( pCur->eState==CURSOR_FAULT );
    rc = moveToRoot(pCur);
    if( rc && rc!=SQLITE_EMPTY ) return rc;
  }

  assert( cursorOwnsBtShared(pCur) );
  assert( (pCur->curFlags & BTCF_WriteFlag)!=0
              && p->pBt->inTransaction==TRANS_WRITE
              && (p->pBt->btsFlags & BTS_READ_ONLY)==0 );
  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );

  /* Assert that the caller has been consistent. If this cursor was opened
  ** expecting an index b-tree, then the caller should be inserting blob
  ** keys with no associated data. If the cursor was opened expecting an
  ** intkey table, the caller should be inserting integer keys with a
  ** blob of associated data.  */
  assert( (flags & BTREE_PREFORMAT) || (pX->pKey==0)==(pCur->pKeyInfo==0) );

  if( pCur->pKeyInfo==0 ){
    assert( pX->pKey==0 );
    /* If this is an insert into a table b-tree, invalidate any incrblob
    ** cursors open on the row being replaced */
    if( p->hasIncrblobCur ){
      invalidateIncrblobCursors(p, pCur->pgnoRoot, pX->nKey, 0);
    }

    /* If BTREE_SAVEPOSITION is set, the cursor must already be pointing
    ** to a row with the same key as the new entry being inserted.
    */
#ifdef SQLITE_DEBUG
    if( flags & BTREE_SAVEPOSITION ){
      assert( pCur->curFlags & BTCF_ValidNKey );
      assert( pX->nKey==pCur->info.nKey );
      assert( loc==0 );
    }
#endif

    /* On the other hand, BTREE_SAVEPOSITION==0 does not imply
    ** that the cursor is not pointing to a row to be overwritten.
    ** So do a complete check.
    */
    if( (pCur->curFlags&BTCF_ValidNKey)!=0 && pX->nKey==pCur->info.nKey ){
      /* The cursor is pointing to the entry that is to be
      ** overwritten */
      assert( pX->nData>=0 && pX->nZero>=0 );
      if( pCur->info.nSize!=0
       && pCur->info.nPayload==(u32)pX->nData+pX->nZero
      ){
        /* New entry is the same size as the old.  Do an overwrite */
        return btreeOverwriteCell(pCur, pX);
      }
      assert( loc==0 );
    }else if( loc==0 ){
      /* The cursor is *not* pointing to the cell to be overwritten, nor
      ** to an adjacent cell.  Move the cursor so that it is pointing either
      ** to the cell to be overwritten or an adjacent cell.
      */
      rc = sqlite3BtreeTableMoveto(pCur, pX->nKey,
               (flags & BTREE_APPEND)!=0, &loc);
      if( rc ) return rc;
    }
  }else{
    /* This is an index or a WITHOUT ROWID table */

    /* If BTREE_SAVEPOSITION is set, the cursor must already be pointing
    ** to a row with the same key as the new entry being inserted.
    */
    assert( (flags & BTREE_SAVEPOSITION)==0 || loc==0 );

    /* If the cursor is not already pointing either to the cell to be
    ** overwritten, or if a new cell is being inserted, if the cursor is
    ** not pointing to an immediately adjacent cell, then move the cursor
    ** so that it does.
    */
    if( loc==0 && (flags & BTREE_SAVEPOSITION)==0 ){
      if( pX->nMem ){
        UnpackedRecord r;
        r.pKeyInfo = pCur->pKeyInfo;
        r.aMem = pX->aMem;
        r.nField = pX->nMem;
        r.default_rc = 0;
        r.eqSeen = 0;
        rc = sqlite3BtreeIndexMoveto(pCur, &r, &loc);
      }else{
        rc = btreeMoveto(pCur, pX->pKey, pX->nKey,
                    (flags & BTREE_APPEND)!=0, &loc);
      }
      if( rc ) return rc;
    }

    /* If the cursor is currently pointing to an entry to be overwritten
    ** and the new content is the same as as the old, then use the
    ** overwrite optimization.
    */
    if( loc==0 ){
      getCellInfo(pCur);
      if( pCur->info.nKey==pX->nKey ){
        BtreePayload x2;
        x2.pData = pX->pKey;
        x2.nData = (int)pX->nKey;  assert( pX->nKey<=0x7fffffff );
        x2.nZero = 0;
        return btreeOverwriteCell(pCur, &x2);
      }
    }
  }
  assert( pCur->eState==CURSOR_VALID
       || (pCur->eState==CURSOR_INVALID && loc) || CORRUPT_DB );

  pPage = pCur->pPage;
  assert( pPage->intKey || pX->nKey>=0 || (flags & BTREE_PREFORMAT) );
  assert( pPage->leaf || !pPage->intKey );
  if( pPage->nFree<0 ){
    if( NEVER(pCur->eState>CURSOR_INVALID) ){
     /* ^^^^^--- due to the moveToRoot() call above */
      rc = SQLITE_CORRUPT_PAGE(pPage);
    }else{
      rc = btreeComputeFreeSpace(pPage);
    }
    if( rc ) return rc;
  }

  TRACE(("INSERT: table=%u nkey=%lld ndata=%u page=%u %s\n",
          pCur->pgnoRoot, pX->nKey, pX->nData, pPage->pgno,
          loc==0 ? "overwrite" : "new entry"));
  assert( pPage->isInit || CORRUPT_DB );
  newCell = p->pBt->pTmpSpace;
  assert( newCell!=0 );
  assert( BTREE_PREFORMAT==OPFLAG_PREFORMAT );
  if( flags & BTREE_PREFORMAT ){
    rc = SQLITE_OK;
    szNew = p->pBt->nPreformatSize;
    if( szNew<4 ){
      szNew = 4;
      newCell[3] = 0;
    }
    if( ISAUTOVACUUM(p->pBt) && szNew>pPage->maxLocal ){
      CellInfo info;
      pPage->xParseCell(pPage, newCell, &info);
      if( info.nPayload!=info.nLocal ){
        Pgno ovfl = get4byte(&newCell[szNew-4]);
        ptrmapPut(p->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, &rc);
        if( NEVER(rc) ) goto end_insert;
      }
    }
  }else{
    rc = fillInCell(pPage, newCell, pX, &szNew);
    if( rc ) goto end_insert;
  }
  assert( szNew==pPage->xCellSize(pPage, newCell) );
  assert( szNew <= MX_CELL_SIZE(p->pBt) );
  idx = pCur->ix;
  pCur->info.nSize = 0;
  if( loc==0 ){
    CellInfo info;
    assert( idx>=0 );
    if( idx>=pPage->nCell ){
      return SQLITE_CORRUPT_PAGE(pPage);
    }
    rc = sqlite3PagerWrite(pPage->pDbPage);
    if( rc ){
      goto end_insert;
    }
    oldCell = findCell(pPage, idx);
    if( !pPage->leaf ){
      memcpy(newCell, oldCell, 4);
    }
    BTREE_CLEAR_CELL(rc, pPage, oldCell, info);
    testcase( pCur->curFlags & BTCF_ValidOvfl );
    invalidateOverflowCache(pCur);
    if( info.nSize==szNew && info.nLocal==info.nPayload
     && (!ISAUTOVACUUM(p->pBt) || szNew<pPage->minLocal)
    ){
      /* Overwrite the old cell with the new if they are the same size.
      ** We could also try to do this if the old cell is smaller, then add
      ** the leftover space to the free list.  But experiments show that
      ** doing that is no faster then skipping this optimization and just
      ** calling dropCell() and insertCell().
      **
      ** This optimization cannot be used on an autovacuum database if the
      ** new entry uses overflow pages, as the insertCell() call below is
      ** necessary to add the PTRMAP_OVERFLOW1 pointer-map entry.  */
      assert( rc==SQLITE_OK ); /* clearCell never fails when nLocal==nPayload */
      if( oldCell < pPage->aData+pPage->hdrOffset+10 ){
        return SQLITE_CORRUPT_PAGE(pPage);
      }
      if( oldCell+szNew > pPage->aDataEnd ){
        return SQLITE_CORRUPT_PAGE(pPage);
      }
      memcpy(oldCell, newCell, szNew);
      return SQLITE_OK;
    }
    dropCell(pPage, idx, info.nSize, &rc);
    if( rc ) goto end_insert;
  }else if( loc<0 && pPage->nCell>0 ){
    assert( pPage->leaf );
    idx = ++pCur->ix;
    pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
  }else{
    assert( pPage->leaf );
  }
  rc = insertCellFast(pPage, idx, newCell, szNew);
  assert( pPage->nOverflow==0 || rc==SQLITE_OK );
  assert( rc!=SQLITE_OK || pPage->nCell>0 || pPage->nOverflow>0 );

  /* If no error has occurred and pPage has an overflow cell, call balance()
  ** to redistribute the cells within the tree. Since balance() may move
  ** the cursor, zero the BtCursor.info.nSize and BTCF_ValidNKey
  ** variables.
  **
  ** Previous versions of SQLite called moveToRoot() to move the cursor
  ** back to the root page as balance() used to invalidate the contents
  ** of BtCursor.apPage[] and BtCursor.aiIdx[]. Instead of doing that,
  ** set the cursor state to "invalid". This makes common insert operations
  ** slightly faster.
  **
  ** There is a subtle but important optimization here too. When inserting
  ** multiple records into an intkey b-tree using a single cursor (as can
  ** happen while processing an "INSERT INTO ... SELECT" statement), it
  ** is advantageous to leave the cursor pointing to the last entry in
  ** the b-tree if possible. If the cursor is left pointing to the last
  ** entry in the table, and the next row inserted has an integer key
  ** larger than the largest existing key, it is possible to insert the
  ** row without seeking the cursor. This can be a big performance boost.
  */
  if( pPage->nOverflow ){
    assert( rc==SQLITE_OK );
    pCur->curFlags &= ~(BTCF_ValidNKey|BTCF_ValidOvfl);
    rc = balance(pCur);

    /* Must make sure nOverflow is reset to zero even if the balance()
    ** fails. Internal data structure corruption will result otherwise.
    ** Also, set the cursor state to invalid. This stops saveCursorPosition()
    ** from trying to save the current position of the cursor.  */
    pCur->pPage->nOverflow = 0;
    pCur->eState = CURSOR_INVALID;
    if( (flags & BTREE_SAVEPOSITION) && rc==SQLITE_OK ){
      btreeReleaseAllCursorPages(pCur);
      if( pCur->pKeyInfo ){
        assert( pCur->pKey==0 );
        pCur->pKey = sqlite3Malloc( pX->nKey );
        if( pCur->pKey==0 ){
          rc = SQLITE_NOMEM;
        }else{
          memcpy(pCur->pKey, pX->pKey, pX->nKey);
        }
      }
      pCur->eState = CURSOR_REQUIRESEEK;
      pCur->nKey = pX->nKey;
    }
  }
  assert( pCur->iPage<0 || pCur->pPage->nOverflow==0 );

end_insert:
  return rc;
}

/*
** This function is used as part of copying the current row from cursor
** pSrc into cursor pDest. If the cursors are open on intkey tables, then
** parameter iKey is used as the rowid value when the record is copied
** into pDest. Otherwise, the record is copied verbatim.
**
** This function does not actually write the new value to cursor pDest.
** Instead, it creates and populates any required overflow pages and
** writes the data for the new cell into the BtShared.pTmpSpace buffer
** for the destination database. The size of the cell, in bytes, is left
** in BtShared.nPreformatSize. The caller completes the insertion by
** calling sqlite3BtreeInsert() with the BTREE_PREFORMAT flag specified.
**
** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
*/
SQLITE_PRIVATE int sqlite3BtreeTransferRow(BtCursor *pDest, BtCursor *pSrc, i64 iKey){
  BtShared *pBt = pDest->pBt;
  u8 *aOut = pBt->pTmpSpace;    /* Pointer to next output buffer */
  const u8 *aIn;                /* Pointer to next input buffer */
  u32 nIn;                      /* Size of input buffer aIn[] */
  u32 nRem;                     /* Bytes of data still to copy */

  getCellInfo(pSrc);
  if( pSrc->info.nPayload<0x80 ){
    *(aOut++) = (u8)pSrc->info.nPayload;
  }else{
    aOut += sqlite3PutVarint(aOut, pSrc->info.nPayload);
  }
  if( pDest->pKeyInfo==0 ) aOut += putVarint(aOut, iKey);
  nIn = pSrc->info.nLocal;
  aIn = pSrc->info.pPayload;
  if( aIn+nIn>pSrc->pPage->aDataEnd ){
    return SQLITE_CORRUPT_PAGE(pSrc->pPage);
  }
  nRem = pSrc->info.nPayload;
  if( nIn==nRem && nIn<pDest->pPage->maxLocal ){
    memcpy(aOut, aIn, nIn);
    pBt->nPreformatSize = nIn + (int)(aOut - pBt->pTmpSpace);
    return SQLITE_OK;
  }else{
    int rc = SQLITE_OK;
    Pager *pSrcPager = pSrc->pBt->pPager;
    u8 *pPgnoOut = 0;
    Pgno ovflIn = 0;
    DbPage *pPageIn = 0;
    MemPage *pPageOut = 0;
    u32 nOut;                     /* Size of output buffer aOut[] */

    nOut = btreePayloadToLocal(pDest->pPage, pSrc->info.nPayload);
    pBt->nPreformatSize = (int)nOut + (int)(aOut - pBt->pTmpSpace);
    if( nOut<pSrc->info.nPayload ){
      pPgnoOut = &aOut[nOut];
      pBt->nPreformatSize += 4;
    }

    if( nRem>nIn ){
      if( aIn+nIn+4>pSrc->pPage->aDataEnd ){
        return SQLITE_CORRUPT_PAGE(pSrc->pPage);
      }
      ovflIn = get4byte(&pSrc->info.pPayload[nIn]);
    }

    do {
      nRem -= nOut;
      do{
        assert( nOut>0 );
        if( nIn>0 ){
          int nCopy = MIN(nOut, nIn);
          memcpy(aOut, aIn, nCopy);
          nOut -= nCopy;
          nIn -= nCopy;
          aOut += nCopy;
          aIn += nCopy;
        }
        if( nOut>0 ){
          sqlite3PagerUnref(pPageIn);
          pPageIn = 0;
          rc = sqlite3PagerGet(pSrcPager, ovflIn, &pPageIn, PAGER_GET_READONLY);
          if( rc==SQLITE_OK ){
            aIn = (const u8*)sqlite3PagerGetData(pPageIn);
            ovflIn = get4byte(aIn);
            aIn += 4;
            nIn = pSrc->pBt->usableSize - 4;
          }
        }
      }while( rc==SQLITE_OK && nOut>0 );

      if( rc==SQLITE_OK && nRem>0 && ALWAYS(pPgnoOut) ){
        Pgno pgnoNew;
        MemPage *pNew = 0;
        rc = allocateBtreePage(pBt, &pNew, &pgnoNew, 0, 0);
        put4byte(pPgnoOut, pgnoNew);
        if( ISAUTOVACUUM(pBt) && pPageOut ){
          ptrmapPut(pBt, pgnoNew, PTRMAP_OVERFLOW2, pPageOut->pgno, &rc);
        }
        releasePage(pPageOut);
        pPageOut = pNew;
        if( pPageOut ){
          pPgnoOut = pPageOut->aData;
          put4byte(pPgnoOut, 0);
          aOut = &pPgnoOut[4];
          nOut = MIN(pBt->usableSize - 4, nRem);
        }
      }
    }while( nRem>0 && rc==SQLITE_OK );

    releasePage(pPageOut);
    sqlite3PagerUnref(pPageIn);
    return rc;
  }
}

/*
** Delete the entry that the cursor is pointing to.
**
** If the BTREE_SAVEPOSITION bit of the flags parameter is zero, then
** the cursor is left pointing at an arbitrary location after the delete.
** But if that bit is set, then the cursor is left in a state such that
** the next call to BtreeNext() or BtreePrev() moves it to the same row
** as it would have been on if the call to BtreeDelete() had been omitted.
**
** The BTREE_AUXDELETE bit of flags indicates that is one of several deletes
** associated with a single table entry and its indexes.  Only one of those
** deletes is considered the "primary" delete.  The primary delete occurs
** on a cursor that is not a BTREE_FORDELETE cursor.  All but one delete
** operation on non-FORDELETE cursors is tagged with the AUXDELETE flag.
** The BTREE_AUXDELETE bit is a hint that is not used by this implementation,
** but which might be used by alternative storage engines.
*/
SQLITE_PRIVATE int sqlite3BtreeDelete(BtCursor *pCur, u8 flags){
  Btree *p = pCur->pBtree;
  BtShared *pBt = p->pBt;
  int rc;                    /* Return code */
  MemPage *pPage;            /* Page to delete cell from */
  unsigned char *pCell;      /* Pointer to cell to delete */
  int iCellIdx;              /* Index of cell to delete */
  int iCellDepth;            /* Depth of node containing pCell */
  CellInfo info;             /* Size of the cell being deleted */
  u8 bPreserve;              /* Keep cursor valid.  2 for CURSOR_SKIPNEXT */

  assert( cursorOwnsBtShared(pCur) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );
  assert( pCur->curFlags & BTCF_WriteFlag );
  assert( hasSharedCacheTableLock(p, pCur->pgnoRoot, pCur->pKeyInfo!=0, 2) );
  assert( !hasReadConflicts(p, pCur->pgnoRoot) );
  assert( (flags & ~(BTREE_SAVEPOSITION | BTREE_AUXDELETE))==0 );
  if( pCur->eState!=CURSOR_VALID ){
    if( pCur->eState>=CURSOR_REQUIRESEEK ){
      rc = btreeRestoreCursorPosition(pCur);
      assert( rc!=SQLITE_OK || CORRUPT_DB || pCur->eState==CURSOR_VALID );
      if( rc || pCur->eState!=CURSOR_VALID ) return rc;
    }else{
      return SQLITE_CORRUPT_PGNO(pCur->pgnoRoot);
    }
  }
  assert( pCur->eState==CURSOR_VALID );

  iCellDepth = pCur->iPage;
  iCellIdx = pCur->ix;
  pPage = pCur->pPage;
  if( pPage->nCell<=iCellIdx ){
    return SQLITE_CORRUPT_PAGE(pPage);
  }
  pCell = findCell(pPage, iCellIdx);
  if( pPage->nFree<0 && btreeComputeFreeSpace(pPage) ){
    return SQLITE_CORRUPT_PAGE(pPage);
  }
  if( pCell<&pPage->aCellIdx[pPage->nCell] ){
    return SQLITE_CORRUPT_PAGE(pPage);
  }

  /* If the BTREE_SAVEPOSITION bit is on, then the cursor position must
  ** be preserved following this delete operation. If the current delete
  ** will cause a b-tree rebalance, then this is done by saving the cursor
  ** key and leaving the cursor in CURSOR_REQUIRESEEK state before
  ** returning.
  **
  ** If the current delete will not cause a rebalance, then the cursor
  ** will be left in CURSOR_SKIPNEXT state pointing to the entry immediately
  ** before or after the deleted entry.
  **
  ** The bPreserve value records which path is required:
  **
  **    bPreserve==0         Not necessary to save the cursor position
  **    bPreserve==1         Use CURSOR_REQUIRESEEK to save the cursor position
  **    bPreserve==2         Cursor won't move.  Set CURSOR_SKIPNEXT.
  */
  bPreserve = (flags & BTREE_SAVEPOSITION)!=0;
  if( bPreserve ){
    if( !pPage->leaf
     || (pPage->nFree+pPage->xCellSize(pPage,pCell)+2) >
                                                   (int)(pBt->usableSize*2/3)
     || pPage->nCell==1  /* See dbfuzz001.test for a test case */
    ){
      /* A b-tree rebalance will be required after deleting this entry.
      ** Save the cursor key.  */
      rc = saveCursorKey(pCur);
      if( rc ) return rc;
    }else{
      bPreserve = 2;
    }
  }

  /* If the page containing the entry to delete is not a leaf page, move
  ** the cursor to the largest entry in the tree that is smaller than
  ** the entry being deleted. This cell will replace the cell being deleted
  ** from the internal node. The 'previous' entry is used for this instead
  ** of the 'next' entry, as the previous entry is always a part of the
  ** sub-tree headed by the child page of the cell being deleted. This makes
  ** balancing the tree following the delete operation easier.  */
  if( !pPage->leaf ){
    rc = sqlite3BtreePrevious(pCur, 0);
    assert( rc!=SQLITE_DONE );
    if( rc ) return rc;
  }

  /* Save the positions of any other cursors open on this table before
  ** making any modifications.  */
  if( pCur->curFlags & BTCF_Multiple ){
    rc = saveAllCursors(pBt, pCur->pgnoRoot, pCur);
    if( rc ) return rc;
  }

  /* If this is a delete operation to remove a row from a table b-tree,
  ** invalidate any incrblob cursors open on the row being deleted.  */
  if( pCur->pKeyInfo==0 && p->hasIncrblobCur ){
    invalidateIncrblobCursors(p, pCur->pgnoRoot, pCur->info.nKey, 0);
  }

  /* Make the page containing the entry to be deleted writable. Then free any
  ** overflow pages associated with the entry and finally remove the cell
  ** itself from within the page.  */
  rc = sqlite3PagerWrite(pPage->pDbPage);
  if( rc ) return rc;
  BTREE_CLEAR_CELL(rc, pPage, pCell, info);
  dropCell(pPage, iCellIdx, info.nSize, &rc);
  if( rc ) return rc;

  /* If the cell deleted was not located on a leaf page, then the cursor
  ** is currently pointing to the largest entry in the sub-tree headed
  ** by the child-page of the cell that was just deleted from an internal
  ** node. The cell from the leaf node needs to be moved to the internal
  ** node to replace the deleted cell.  */
  if( !pPage->leaf ){
    MemPage *pLeaf = pCur->pPage;
    int nCell;
    Pgno n;
    unsigned char *pTmp;

    if( pLeaf->nFree<0 ){
      rc = btreeComputeFreeSpace(pLeaf);
      if( rc ) return rc;
    }
    if( iCellDepth<pCur->iPage-1 ){
      n = pCur->apPage[iCellDepth+1]->pgno;
    }else{
      n = pCur->pPage->pgno;
    }
    pCell = findCell(pLeaf, pLeaf->nCell-1);
    if( pCell<&pLeaf->aData[4] ) return SQLITE_CORRUPT_PAGE(pLeaf);
    nCell = pLeaf->xCellSize(pLeaf, pCell);
    assert( MX_CELL_SIZE(pBt) >= nCell );
    pTmp = pBt->pTmpSpace;
    assert( pTmp!=0 );
    rc = sqlite3PagerWrite(pLeaf->pDbPage);
    if( rc==SQLITE_OK ){
      rc = insertCell(pPage, iCellIdx, pCell-4, nCell+4, pTmp, n);
    }
    dropCell(pLeaf, pLeaf->nCell-1, nCell, &rc);
    if( rc ) return rc;
  }

  /* Balance the tree. If the entry deleted was located on a leaf page,
  ** then the cursor still points to that page. In this case the first
  ** call to balance() repairs the tree, and the if(...) condition is
  ** never true.
  **
  ** Otherwise, if the entry deleted was on an internal node page, then
  ** pCur is pointing to the leaf page from which a cell was removed to
  ** replace the cell deleted from the internal node. This is slightly
  ** tricky as the leaf node may be underfull, and the internal node may
  ** be either under or overfull. In this case run the balancing algorithm
  ** on the leaf node first. If the balance proceeds far enough up the
  ** tree that we can be sure that any problem in the internal node has
  ** been corrected, so be it. Otherwise, after balancing the leaf node,
  ** walk the cursor up the tree to the internal node and balance it as
  ** well.  */
  assert( pCur->pPage->nOverflow==0 );
  assert( pCur->pPage->nFree>=0 );
  if( pCur->pPage->nFree*3<=(int)pCur->pBt->usableSize*2 ){
    /* Optimization: If the free space is less than 2/3rds of the page,
    ** then balance() will always be a no-op.  No need to invoke it. */
    rc = SQLITE_OK;
  }else{
    rc = balance(pCur);
  }
  if( rc==SQLITE_OK && pCur->iPage>iCellDepth ){
    releasePageNotNull(pCur->pPage);
    pCur->iPage--;
    while( pCur->iPage>iCellDepth ){
      releasePage(pCur->apPage[pCur->iPage--]);
    }
    pCur->pPage = pCur->apPage[pCur->iPage];
    rc = balance(pCur);
  }

  if( rc==SQLITE_OK ){
    if( bPreserve>1 ){
      assert( (pCur->iPage==iCellDepth || CORRUPT_DB) );
      assert( pPage==pCur->pPage || CORRUPT_DB );
      assert( (pPage->nCell>0 || CORRUPT_DB) && iCellIdx<=pPage->nCell );
      pCur->eState = CURSOR_SKIPNEXT;
      if( iCellIdx>=pPage->nCell ){
        pCur->skipNext = -1;
        pCur->ix = pPage->nCell-1;
      }else{
        pCur->skipNext = 1;
      }
    }else{
      rc = moveToRoot(pCur);
      if( bPreserve ){
        btreeReleaseAllCursorPages(pCur);
        pCur->eState = CURSOR_REQUIRESEEK;
      }
      if( rc==SQLITE_EMPTY ) rc = SQLITE_OK;
    }
  }
  return rc;
}

/*
** Create a new BTree table.  Write into *piTable the page
** number for the root page of the new table.
**
** The type of type is determined by the flags parameter.  Only the
** following values of flags are currently in use.  Other values for
** flags might not work:
**
**     BTREE_INTKEY|BTREE_LEAFDATA     Used for SQL tables with rowid keys
**     BTREE_ZERODATA                  Used for SQL indices
*/
static int btreeCreateTable(Btree *p, Pgno *piTable, int createTabFlags){
  BtShared *pBt = p->pBt;
  MemPage *pRoot;
  Pgno pgnoRoot;
  int rc;
  int ptfFlags;          /* Page-type flags for the root page of new table */

  assert( sqlite3BtreeHoldsMutex(p) );
  assert( pBt->inTransaction==TRANS_WRITE );
  assert( (pBt->btsFlags & BTS_READ_ONLY)==0 );

#ifdef SQLITE_OMIT_AUTOVACUUM
  rc = allocateBtreePage(pBt, &pRoot, &pgnoRoot, 1, 0);
  if( rc ){
    return rc;
  }
#else
  if( pBt->autoVacuum ){
    Pgno pgnoMove;      /* Move a page here to make room for the root-page */
    MemPage *pPageMove; /* The page to move to. */

    /* Creating a new table may probably require moving an existing database
    ** to make room for the new tables root page. In case this page turns
    ** out to be an overflow page, delete all overflow page-map caches
    ** held by open cursors.
    */
    invalidateAllOverflowCache(pBt);

    /* Read the value of meta[3] from the database to determine where the
    ** root page of the new table should go. meta[3] is the largest root-page
    ** created so far, so the new root-page is (meta[3]+1).
    */
    sqlite3BtreeGetMeta(p, BTREE_LARGEST_ROOT_PAGE, &pgnoRoot);
    if( pgnoRoot>btreePagecount(pBt) ){
      return SQLITE_CORRUPT_PGNO(pgnoRoot);
    }
    pgnoRoot++;

    /* The new root-page may not be allocated on a pointer-map page, or the
    ** PENDING_BYTE page.
    */
    while( pgnoRoot==PTRMAP_PAGENO(pBt, pgnoRoot) ||
        pgnoRoot==PENDING_BYTE_PAGE(pBt) ){
      pgnoRoot++;
    }
    assert( pgnoRoot>=3 );

    /* Allocate a page. The page that currently resides at pgnoRoot will
    ** be moved to the allocated page (unless the allocated page happens
    ** to reside at pgnoRoot).
    */
    rc = allocateBtreePage(pBt, &pPageMove, &pgnoMove, pgnoRoot, BTALLOC_EXACT);
    if( rc!=SQLITE_OK ){
      return rc;
    }

    if( pgnoMove!=pgnoRoot ){
      /* pgnoRoot is the page that will be used for the root-page of
      ** the new table (assuming an error did not occur). But we were
      ** allocated pgnoMove. If required (i.e. if it was not allocated
      ** by extending the file), the current page at position pgnoMove
      ** is already journaled.
      */
      u8 eType = 0;
      Pgno iPtrPage = 0;

      /* Save the positions of any open cursors. This is required in
      ** case they are holding a reference to an xFetch reference
      ** corresponding to page pgnoRoot.  */
      rc = saveAllCursors(pBt, 0, 0);
      releasePage(pPageMove);
      if( rc!=SQLITE_OK ){
        return rc;
      }

      /* Move the page currently at pgnoRoot to pgnoMove. */
      rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0);
      if( rc!=SQLITE_OK ){
        return rc;
      }
      rc = ptrmapGet(pBt, pgnoRoot, &eType, &iPtrPage);
      if( eType==PTRMAP_ROOTPAGE || eType==PTRMAP_FREEPAGE ){
        rc = SQLITE_CORRUPT_PGNO(pgnoRoot);
      }
      if( rc!=SQLITE_OK ){
        releasePage(pRoot);
        return rc;
      }
      assert( eType!=PTRMAP_ROOTPAGE );
      assert( eType!=PTRMAP_FREEPAGE );
      rc = relocatePage(pBt, pRoot, eType, iPtrPage, pgnoMove, 0);
      releasePage(pRoot);

      /* Obtain the page at pgnoRoot */
      if( rc!=SQLITE_OK ){
        return rc;
      }
      rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0);
      if( rc!=SQLITE_OK ){
        return rc;
      }
      rc = sqlite3PagerWrite(pRoot->pDbPage);
      if( rc!=SQLITE_OK ){
        releasePage(pRoot);
        return rc;
      }
    }else{
      pRoot = pPageMove;
    }

    /* Update the pointer-map and meta-data with the new root-page number. */
    ptrmapPut(pBt, pgnoRoot, PTRMAP_ROOTPAGE, 0, &rc);
    if( rc ){
      releasePage(pRoot);
      return rc;
    }

    /* When the new root page was allocated, page 1 was made writable in
    ** order either to increase the database filesize, or to decrement the
    ** freelist count.  Hence, the sqlite3BtreeUpdateMeta() call cannot fail.
    */
    assert( sqlite3PagerIswriteable(pBt->pPage1->pDbPage) );
    rc = sqlite3BtreeUpdateMeta(p, 4, pgnoRoot);
    if( NEVER(rc) ){
      releasePage(pRoot);
      return rc;
    }

sqlite3.c  view on Meta::CPAN

  BtShared *pBt,           /* The BTree that contains the table */
  Pgno pgno,               /* Page number to clear */
  int freePageFlag,        /* Deallocate page if true */
  i64 *pnChange            /* Add number of Cells freed to this counter */
){
  MemPage *pPage;
  int rc;
  unsigned char *pCell;
  int i;
  int hdr;
  CellInfo info;

  assert( sqlite3_mutex_held(pBt->mutex) );
  if( pgno>btreePagecount(pBt) ){
    return SQLITE_CORRUPT_PGNO(pgno);
  }
  rc = getAndInitPage(pBt, pgno, &pPage, 0);
  if( rc ) return rc;
  if( (pBt->openFlags & BTREE_SINGLE)==0
   && sqlite3PagerPageRefcount(pPage->pDbPage) != (1 + (pgno==1))
  ){
    rc = SQLITE_CORRUPT_PAGE(pPage);
    goto cleardatabasepage_out;
  }
  hdr = pPage->hdrOffset;
  for(i=0; i<pPage->nCell; i++){
    pCell = findCell(pPage, i);
    if( !pPage->leaf ){
      rc = clearDatabasePage(pBt, get4byte(pCell), 1, pnChange);
      if( rc ) goto cleardatabasepage_out;
    }
    BTREE_CLEAR_CELL(rc, pPage, pCell, info);
    if( rc ) goto cleardatabasepage_out;
  }
  if( !pPage->leaf ){
    rc = clearDatabasePage(pBt, get4byte(&pPage->aData[hdr+8]), 1, pnChange);
    if( rc ) goto cleardatabasepage_out;
    if( pPage->intKey ) pnChange = 0;
  }
  if( pnChange ){
    testcase( !pPage->intKey );
    *pnChange += pPage->nCell;
  }
  if( freePageFlag ){
    freePage(pPage, &rc);
  }else if( (rc = sqlite3PagerWrite(pPage->pDbPage))==0 ){
    zeroPage(pPage, pPage->aData[hdr] | PTF_LEAF);
  }

cleardatabasepage_out:
  releasePage(pPage);
  return rc;
}

/*
** Delete all information from a single table in the database.  iTable is
** the page number of the root of the table.  After this routine returns,
** the root page is empty, but still exists.
**
** This routine will fail with SQLITE_LOCKED if there are any open
** read cursors on the table.  Open write cursors are moved to the
** root of the table.
**
** If pnChange is not NULL, then the integer value pointed to by pnChange
** is incremented by the number of entries in the table.
*/
SQLITE_PRIVATE int sqlite3BtreeClearTable(Btree *p, int iTable, i64 *pnChange){
  int rc;
  BtShared *pBt = p->pBt;
  sqlite3BtreeEnter(p);
  assert( p->inTrans==TRANS_WRITE );

  rc = saveAllCursors(pBt, (Pgno)iTable, 0);

  if( SQLITE_OK==rc ){
    /* Invalidate all incrblob cursors open on table iTable (assuming iTable
    ** is the root of a table b-tree - if it is not, the following call is
    ** a no-op).  */
    if( p->hasIncrblobCur ){
      invalidateIncrblobCursors(p, (Pgno)iTable, 0, 1);
    }
    rc = clearDatabasePage(pBt, (Pgno)iTable, 0, pnChange);
  }
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** Delete all information from the single table that pCur is open on.
**
** This routine only work for pCur on an ephemeral table.
*/
SQLITE_PRIVATE int sqlite3BtreeClearTableOfCursor(BtCursor *pCur){
  return sqlite3BtreeClearTable(pCur->pBtree, pCur->pgnoRoot, 0);
}

/*
** Erase all information in a table and add the root of the table to
** the freelist.  Except, the root of the principle table (the one on
** page 1) is never added to the freelist.
**
** This routine will fail with SQLITE_LOCKED if there are any open
** cursors on the table.
**
** If AUTOVACUUM is enabled and the page at iTable is not the last
** root page in the database file, then the last root page
** in the database file is moved into the slot formerly occupied by
** iTable and that last slot formerly occupied by the last root page
** is added to the freelist instead of iTable.  In this say, all
** root pages are kept at the beginning of the database file, which
** is necessary for AUTOVACUUM to work right.  *piMoved is set to the
** page number that used to be the last root page in the file before
** the move.  If no page gets moved, *piMoved is set to 0.
** The last root page is recorded in meta[3] and the value of
** meta[3] is updated by this procedure.
*/
static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
  int rc;
  MemPage *pPage = 0;
  BtShared *pBt = p->pBt;

  assert( sqlite3BtreeHoldsMutex(p) );
  assert( p->inTrans==TRANS_WRITE );
  assert( iTable>=2 );
  if( iTable>btreePagecount(pBt) ){
    return SQLITE_CORRUPT_PGNO(iTable);
  }

  rc = sqlite3BtreeClearTable(p, iTable, 0);
  if( rc ) return rc;
  rc = btreeGetPage(pBt, (Pgno)iTable, &pPage, 0);
  if( NEVER(rc) ){
    releasePage(pPage);
    return rc;
  }

  *piMoved = 0;

#ifdef SQLITE_OMIT_AUTOVACUUM
  freePage(pPage, &rc);
  releasePage(pPage);
#else
  if( pBt->autoVacuum ){
    Pgno maxRootPgno;
    sqlite3BtreeGetMeta(p, BTREE_LARGEST_ROOT_PAGE, &maxRootPgno);

    if( iTable==maxRootPgno ){
      /* If the table being dropped is the table with the largest root-page
      ** number in the database, put the root page on the free list.
      */
      freePage(pPage, &rc);
      releasePage(pPage);
      if( rc!=SQLITE_OK ){
        return rc;
      }
    }else{
      /* The table being dropped does not have the largest root-page
      ** number in the database. So move the page that does into the
      ** gap left by the deleted root-page.
      */
      MemPage *pMove;
      releasePage(pPage);
      rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0);

sqlite3.c  view on Meta::CPAN

** from the pager.  The BTREE_DATA_VERSION value is not actually stored in the
** database file.  It is a number computed by the pager.  But its access
** pattern is the same as header meta values, and so it is convenient to
** read it from this routine.
*/
SQLITE_PRIVATE void sqlite3BtreeGetMeta(Btree *p, int idx, u32 *pMeta){
  BtShared *pBt = p->pBt;

  sqlite3BtreeEnter(p);
  assert( p->inTrans>TRANS_NONE );
  assert( SQLITE_OK==querySharedCacheTableLock(p, SCHEMA_ROOT, READ_LOCK) );
  assert( pBt->pPage1 );
  assert( idx>=0 && idx<=15 );

  if( idx==BTREE_DATA_VERSION ){
    *pMeta = sqlite3PagerDataVersion(pBt->pPager) + p->iBDataVersion;
  }else{
    *pMeta = get4byte(&pBt->pPage1->aData[36 + idx*4]);
  }

  /* If auto-vacuum is disabled in this build and this is an auto-vacuum
  ** database, mark the database as read-only.  */
#ifdef SQLITE_OMIT_AUTOVACUUM
  if( idx==BTREE_LARGEST_ROOT_PAGE && *pMeta>0 ){
    pBt->btsFlags |= BTS_READ_ONLY;
  }
#endif

  sqlite3BtreeLeave(p);
}

/*
** Write meta-information back into the database.  Meta[0] is
** read-only and may not be written.
*/
SQLITE_PRIVATE int sqlite3BtreeUpdateMeta(Btree *p, int idx, u32 iMeta){
  BtShared *pBt = p->pBt;
  unsigned char *pP1;
  int rc;
  assert( idx>=1 && idx<=15 );
  sqlite3BtreeEnter(p);
  assert( p->inTrans==TRANS_WRITE );
  assert( pBt->pPage1!=0 );
  pP1 = pBt->pPage1->aData;
  rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
  if( rc==SQLITE_OK ){
    put4byte(&pP1[36 + idx*4], iMeta);
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( idx==BTREE_INCR_VACUUM ){
      assert( pBt->autoVacuum || iMeta==0 );
      assert( iMeta==0 || iMeta==1 );
      pBt->incrVacuum = (u8)iMeta;
    }
#endif
  }
  sqlite3BtreeLeave(p);
  return rc;
}

/*
** The first argument, pCur, is a cursor opened on some b-tree. Count the
** number of entries in the b-tree and write the result to *pnEntry.
**
** SQLITE_OK is returned if the operation is successfully executed.
** Otherwise, if an error is encountered (i.e. an IO error or database
** corruption) an SQLite error code is returned.
*/
SQLITE_PRIVATE int sqlite3BtreeCount(sqlite3 *db, BtCursor *pCur, i64 *pnEntry){
  i64 nEntry = 0;                      /* Value to return in *pnEntry */
  int rc;                              /* Return code */

  rc = moveToRoot(pCur);
  if( rc==SQLITE_EMPTY ){
    *pnEntry = 0;
    return SQLITE_OK;
  }

  /* Unless an error occurs, the following loop runs one iteration for each
  ** page in the B-Tree structure (not including overflow pages).
  */
  while( rc==SQLITE_OK && !AtomicLoad(&db->u1.isInterrupted) ){
    int iIdx;                          /* Index of child node in parent */
    MemPage *pPage;                    /* Current page of the b-tree */

    /* If this is a leaf page or the tree is not an int-key tree, then
    ** this page contains countable entries. Increment the entry counter
    ** accordingly.
    */
    pPage = pCur->pPage;
    if( pPage->leaf || !pPage->intKey ){
      nEntry += pPage->nCell;
    }

    /* pPage is a leaf node. This loop navigates the cursor so that it
    ** points to the first interior cell that it points to the parent of
    ** the next page in the tree that has not yet been visited. The
    ** pCur->aiIdx[pCur->iPage] value is set to the index of the parent cell
    ** of the page, or to the number of cells in the page if the next page
    ** to visit is the right-child of its parent.
    **
    ** If all pages in the tree have been visited, return SQLITE_OK to the
    ** caller.
    */
    if( pPage->leaf ){
      do {
        if( pCur->iPage==0 ){
          /* All pages of the b-tree have been visited. Return successfully. */
          *pnEntry = nEntry;
          return moveToRoot(pCur);
        }
        moveToParent(pCur);
      }while ( pCur->ix>=pCur->pPage->nCell );

      pCur->ix++;
      pPage = pCur->pPage;
    }

    /* Descend to the child node of the cell that the cursor currently
    ** points at. This is the right-child if (iIdx==pPage->nCell).
    */
    iIdx = pCur->ix;
    if( iIdx==pPage->nCell ){
      rc = moveToChild(pCur, get4byte(&pPage->aData[pPage->hdrOffset+8]));
    }else{
      rc = moveToChild(pCur, get4byte(findCell(pPage, iIdx)));
    }
  }

  /* An error has occurred. Return an error code. */
  return rc;
}

/*
** Return the pager associated with a BTree.  This routine is used for
** testing and debugging only.
*/
SQLITE_PRIVATE Pager *sqlite3BtreePager(Btree *p){
  return p->pBt->pPager;
}

#ifndef SQLITE_OMIT_INTEGRITY_CHECK
/*
** Record an OOM error during integrity_check
*/
static void checkOom(IntegrityCk *pCheck){
  pCheck->rc = SQLITE_NOMEM;
  pCheck->mxErr = 0;  /* Causes integrity_check processing to stop */
  if( pCheck->nErr==0 ) pCheck->nErr++;
}

/*
** Invoke the progress handler, if appropriate.  Also check for an
** interrupt.
*/
static void checkProgress(IntegrityCk *pCheck){
  sqlite3 *db = pCheck->db;
  if( AtomicLoad(&db->u1.isInterrupted) ){
    pCheck->rc = SQLITE_INTERRUPT;
    pCheck->nErr++;
    pCheck->mxErr = 0;
  }
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  if( db->xProgress ){
    assert( db->nProgressOps>0 );
    pCheck->nStep++;
    if( (pCheck->nStep % db->nProgressOps)==0
     && db->xProgress(db->pProgressArg)
    ){
      pCheck->rc = SQLITE_INTERRUPT;
      pCheck->nErr++;
      pCheck->mxErr = 0;
    }
  }
#endif
}

/*
** Append a message to the error message string.

sqlite3.c  view on Meta::CPAN

** xFree argument when the memory allocation was made is invoked on the
** blob of allocated memory. The xFree function should not call sqlite3_free()
** on the memory, the btree layer does that.
*/
SQLITE_PRIVATE void *sqlite3BtreeSchema(Btree *p, int nBytes, void(*xFree)(void *)){
  BtShared *pBt = p->pBt;
  assert( nBytes==0 || nBytes==sizeof(Schema) );
  sqlite3BtreeEnter(p);
  if( !pBt->pSchema && nBytes ){
    pBt->pSchema = sqlite3DbMallocZero(0, nBytes);
    pBt->xFreeSchema = xFree;
  }
  sqlite3BtreeLeave(p);
  return pBt->pSchema;
}

/*
** Return SQLITE_LOCKED_SHAREDCACHE if another user of the same shared
** btree as the argument handle holds an exclusive lock on the
** sqlite_schema table. Otherwise SQLITE_OK.
*/
SQLITE_PRIVATE int sqlite3BtreeSchemaLocked(Btree *p){
  int rc;
  UNUSED_PARAMETER(p);  /* only used in DEBUG builds */
  assert( sqlite3_mutex_held(p->db->mutex) );
  sqlite3BtreeEnter(p);
  rc = querySharedCacheTableLock(p, SCHEMA_ROOT, READ_LOCK);
  assert( rc==SQLITE_OK || rc==SQLITE_LOCKED_SHAREDCACHE );
  sqlite3BtreeLeave(p);
  return rc;
}


#ifndef SQLITE_OMIT_SHARED_CACHE
/*
** Obtain a lock on the table whose root page is iTab.  The
** lock is a write lock if isWritelock is true or a read lock
** if it is false.
*/
SQLITE_PRIVATE int sqlite3BtreeLockTable(Btree *p, int iTab, u8 isWriteLock){
  int rc = SQLITE_OK;
  assert( p->inTrans!=TRANS_NONE );
  if( p->sharable ){
    u8 lockType = READ_LOCK + isWriteLock;
    assert( READ_LOCK+1==WRITE_LOCK );
    assert( isWriteLock==0 || isWriteLock==1 );

    sqlite3BtreeEnter(p);
    rc = querySharedCacheTableLock(p, iTab, lockType);
    if( rc==SQLITE_OK ){
      rc = setSharedCacheTableLock(p, iTab, lockType);
    }
    sqlite3BtreeLeave(p);
  }
  return rc;
}
#endif

#ifndef SQLITE_OMIT_INCRBLOB
/*
** Argument pCsr must be a cursor opened for writing on an
** INTKEY table currently pointing at a valid table entry.
** This function modifies the data stored as part of that entry.
**
** Only the data content may only be modified, it is not possible to
** change the length of the data stored. If this function is called with
** parameters that attempt to write past the end of the existing data,
** no modifications are made and SQLITE_CORRUPT is returned.
*/
SQLITE_PRIVATE int sqlite3BtreePutData(BtCursor *pCsr, u32 offset, u32 amt, void *z){
  int rc;
  assert( cursorOwnsBtShared(pCsr) );
  assert( sqlite3_mutex_held(pCsr->pBtree->db->mutex) );
  assert( pCsr->curFlags & BTCF_Incrblob );

  rc = restoreCursorPosition(pCsr);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  assert( pCsr->eState!=CURSOR_REQUIRESEEK );
  if( pCsr->eState!=CURSOR_VALID ){
    return SQLITE_ABORT;
  }

  /* Save the positions of all other cursors open on this table. This is
  ** required in case any of them are holding references to an xFetch
  ** version of the b-tree page modified by the accessPayload call below.
  **
  ** Note that pCsr must be open on a INTKEY table and saveCursorPosition()
  ** and hence saveAllCursors() cannot fail on a BTREE_INTKEY table, hence
  ** saveAllCursors can only return SQLITE_OK.
  */
  VVA_ONLY(rc =) saveAllCursors(pCsr->pBt, pCsr->pgnoRoot, pCsr);
  assert( rc==SQLITE_OK );

  /* Check some assumptions:
  **   (a) the cursor is open for writing,
  **   (b) there is a read/write transaction open,
  **   (c) the connection holds a write-lock on the table (if required),
  **   (d) there are no conflicting read-locks, and
  **   (e) the cursor points at a valid row of an intKey table.
  */
  if( (pCsr->curFlags & BTCF_WriteFlag)==0 ){
    return SQLITE_READONLY;
  }
  assert( (pCsr->pBt->btsFlags & BTS_READ_ONLY)==0
              && pCsr->pBt->inTransaction==TRANS_WRITE );
  assert( hasSharedCacheTableLock(pCsr->pBtree, pCsr->pgnoRoot, 0, 2) );
  assert( !hasReadConflicts(pCsr->pBtree, pCsr->pgnoRoot) );
  assert( pCsr->pPage->intKey );

  return accessPayload(pCsr, offset, amt, (unsigned char *)z, 1);
}

/*
** Mark this cursor as an incremental blob cursor.
*/
SQLITE_PRIVATE void sqlite3BtreeIncrblobCursor(BtCursor *pCur){
  pCur->curFlags |= BTCF_Incrblob;
  pCur->pBtree->hasIncrblobCur = 1;
}
#endif

/*
** Set both the "read version" (single byte at byte offset 18) and
** "write version" (single byte at byte offset 19) fields in the database
** header to iVersion.
*/
SQLITE_PRIVATE int sqlite3BtreeSetVersion(Btree *pBtree, int iVersion){
  BtShared *pBt = pBtree->pBt;
  int rc;                         /* Return code */

  assert( iVersion==1 || iVersion==2 );

  /* If setting the version fields to 1, do not automatically open the
  ** WAL connection, even if the version fields are currently set to 2.
  */
  pBt->btsFlags &= ~BTS_NO_WAL;
  if( iVersion==1 ) pBt->btsFlags |= BTS_NO_WAL;

  rc = sqlite3BtreeBeginTrans(pBtree, 0, 0);
  if( rc==SQLITE_OK ){
    u8 *aData = pBt->pPage1->aData;
    if( aData[18]!=(u8)iVersion || aData[19]!=(u8)iVersion ){
      rc = sqlite3BtreeBeginTrans(pBtree, 2, 0);
      if( rc==SQLITE_OK ){
        rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
        if( rc==SQLITE_OK ){
          aData[18] = (u8)iVersion;
          aData[19] = (u8)iVersion;
        }
      }
    }
  }

  pBt->btsFlags &= ~BTS_NO_WAL;
  return rc;
}

/*
** Return true if the cursor has a hint specified.  This routine is
** only used from within assert() statements
*/
SQLITE_PRIVATE int sqlite3BtreeCursorHasHint(BtCursor *pCsr, unsigned int mask){
  return (pCsr->hints & mask)!=0;
}

/*
** Return true if the given Btree is read-only.
*/
SQLITE_PRIVATE int sqlite3BtreeIsReadonly(Btree *p){
  return (p->pBt->btsFlags & BTS_READ_ONLY)!=0;
}

/*
** Return the size of the header added to each page by this module.
*/
SQLITE_PRIVATE int sqlite3HeaderSizeBtree(void){ return ROUND8(sizeof(MemPage)); }

/*
** If no transaction is active and the database is not a temp-db, clear
** the in-memory pager cache.
*/
SQLITE_PRIVATE void sqlite3BtreeClearCache(Btree *p){
  BtShared *pBt = p->pBt;
  if( pBt->inTransaction==TRANS_NONE ){
    sqlite3PagerClearCache(pBt->pPager);
  }
}

#if !defined(SQLITE_OMIT_SHARED_CACHE)
/*
** Return true if the Btree passed as the only argument is sharable.
*/
SQLITE_PRIVATE int sqlite3BtreeSharable(Btree *p){
  return p->sharable;
}

/*
** Return the number of connections to the BtShared object accessed by
** the Btree handle passed as the only argument. For private caches
** this is always 1. For shared caches it may be 1 or greater.
*/
SQLITE_PRIVATE int sqlite3BtreeConnectionCount(Btree *p){
  testcase( p->sharable );
  return p->pBt->nRef;
}
#endif

/************** End of btree.c ***********************************************/
/************** Begin file backup.c ******************************************/
/*
** 2009 January 28
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**

sqlite3.c  view on Meta::CPAN

**
**   assert( sqlite3VdbeAssertMayAbort(pParse->pVdbe, pParse->mayAbort) );
*/
SQLITE_PRIVATE int sqlite3VdbeAssertMayAbort(Vdbe *v, int mayAbort){
  int hasAbort = 0;
  int hasFkCounter = 0;
  int hasCreateTable = 0;
  int hasCreateIndex = 0;
  int hasInitCoroutine = 0;
  Op *pOp;
  VdbeOpIter sIter;

  if( v==0 ) return 0;
  memset(&sIter, 0, sizeof(sIter));
  sIter.v = v;

  while( (pOp = opIterNext(&sIter))!=0 ){
    int opcode = pOp->opcode;
    if( opcode==OP_Destroy || opcode==OP_VUpdate || opcode==OP_VRename
     || opcode==OP_VDestroy
     || opcode==OP_VCreate
     || opcode==OP_ParseSchema
     || opcode==OP_Function || opcode==OP_PureFunc
     || ((opcode==OP_Halt || opcode==OP_HaltIfNull)
      && ((pOp->p1)!=SQLITE_OK && pOp->p2==OE_Abort))
    ){
      hasAbort = 1;
      break;
    }
    if( opcode==OP_CreateBtree && pOp->p3==BTREE_INTKEY ) hasCreateTable = 1;
    if( mayAbort ){
      /* hasCreateIndex may also be set for some DELETE statements that use
      ** OP_Clear. So this routine may end up returning true in the case
      ** where a "DELETE FROM tbl" has a statement-journal but does not
      ** require one. This is not so bad - it is an inefficiency, not a bug. */
      if( opcode==OP_CreateBtree && pOp->p3==BTREE_BLOBKEY ) hasCreateIndex = 1;
      if( opcode==OP_Clear ) hasCreateIndex = 1;
    }
    if( opcode==OP_InitCoroutine ) hasInitCoroutine = 1;
#ifndef SQLITE_OMIT_FOREIGN_KEY
    if( opcode==OP_FkCounter && pOp->p1==0 && pOp->p2==1 ){
      hasFkCounter = 1;
    }
#endif
  }
  sqlite3DbFree(v->db, sIter.apSub);

  /* Return true if hasAbort==mayAbort. Or if a malloc failure occurred.
  ** If malloc failed, then the while() loop above may not have iterated
  ** through all opcodes and hasAbort may be set incorrectly. Return
  ** true for this case to prevent the assert() in the callers frame
  ** from failing.  */
  return ( v->db->mallocFailed || hasAbort==mayAbort || hasFkCounter
        || (hasCreateTable && hasInitCoroutine) || hasCreateIndex
  );
}
#endif /* SQLITE_DEBUG - the sqlite3AssertMayAbort() function */

#ifdef SQLITE_DEBUG
/*
** Increment the nWrite counter in the VDBE if the cursor is not an
** ephemeral cursor, or if the cursor argument is NULL.
*/
SQLITE_PRIVATE void sqlite3VdbeIncrWriteCounter(Vdbe *p, VdbeCursor *pC){
  if( pC==0
   || (pC->eCurType!=CURTYPE_SORTER
       && pC->eCurType!=CURTYPE_PSEUDO
       && !pC->isEphemeral)
  ){
    p->nWrite++;
  }
}
#endif

#ifdef SQLITE_DEBUG
/*
** Assert if an Abort at this point in time might result in a corrupt
** database.
*/
SQLITE_PRIVATE void sqlite3VdbeAssertAbortable(Vdbe *p){
  assert( p->nWrite==0 || p->usesStmtJournal );
}
#endif

/*
** This routine is called after all opcodes have been inserted.  It loops
** through all the opcodes and fixes up some details.
**
** (1) For each jump instruction with a negative P2 value (a label)
**     resolve the P2 value to an actual address.
**
** (2) Compute the maximum number of arguments used by the xUpdate/xFilter
**     methods of any virtual table and store that value in *pMaxVtabArgs.
**
** (3) Update the Vdbe.readOnly and Vdbe.bIsReader flags to accurately
**     indicate what the prepared statement actually does.
**
** (4) (discontinued)
**
** (5) Reclaim the memory allocated for storing labels.
**
** This routine will only function correctly if the mkopcodeh.tcl generator
** script numbers the opcodes correctly.  Changes to this routine must be
** coordinated with changes to mkopcodeh.tcl.
*/
static void resolveP2Values(Vdbe *p, int *pMaxVtabArgs){
  int nMaxVtabArgs = *pMaxVtabArgs;
  Op *pOp;
  Parse *pParse = p->pParse;
  int *aLabel = pParse->aLabel;

  assert( pParse->db->mallocFailed==0 ); /* tag-20230419-1 */
  p->readOnly = 1;
  p->bIsReader = 0;
  pOp = &p->aOp[p->nOp-1];
  assert( p->aOp[0].opcode==OP_Init );
  while( 1 /* Loop terminates when it reaches the OP_Init opcode */ ){
    /* Only JUMP opcodes and the short list of special opcodes in the switch
    ** below need to be considered.  The mkopcodeh.tcl generator script groups
    ** all these opcodes together near the front of the opcode list.  Skip
    ** any opcode that does not need processing by virtual of the fact that
    ** it is larger than SQLITE_MX_JUMP_OPCODE, as a performance optimization.

sqlite3.c  view on Meta::CPAN

#if defined(SQLITE_DEBUG)
  int i;
#endif
  assert( p!=0 );
  assert( p->eVdbeState==VDBE_INIT_STATE
       || p->eVdbeState==VDBE_READY_STATE
       || p->eVdbeState==VDBE_HALT_STATE );

  /* There should be at least one opcode.
  */
  assert( p->nOp>0 );

  p->eVdbeState = VDBE_READY_STATE;

#ifdef SQLITE_DEBUG
  for(i=0; i<p->nMem; i++){
    assert( p->aMem[i].db==p->db );
  }
#endif
  p->pc = -1;
  p->rc = SQLITE_OK;
  p->errorAction = OE_Abort;
  p->nChange = 0;
  p->cacheCtr = 1;
  p->minWriteFileFormat = 255;
  p->iStatement = 0;
  p->nFkConstraint = 0;
#ifdef VDBE_PROFILE
  for(i=0; i<p->nOp; i++){
    p->aOp[i].nExec = 0;
    p->aOp[i].nCycle = 0;
  }
#endif
}

/*
** Prepare a virtual machine for execution for the first time after
** creating the virtual machine.  This involves things such
** as allocating registers and initializing the program counter.
** After the VDBE has be prepped, it can be executed by one or more
** calls to sqlite3VdbeExec().
**
** This function may be called exactly once on each virtual machine.
** After this routine is called the VM has been "packaged" and is ready
** to run.  After this routine is called, further calls to
** sqlite3VdbeAddOp() functions are prohibited.  This routine disconnects
** the Vdbe from the Parse object that helped generate it so that the
** the Vdbe becomes an independent entity and the Parse object can be
** destroyed.
**
** Use the sqlite3VdbeRewind() procedure to restore a virtual machine back
** to its initial state after it has been run.
*/
SQLITE_PRIVATE void sqlite3VdbeMakeReady(
  Vdbe *p,                       /* The VDBE */
  Parse *pParse                  /* Parsing context */
){
  sqlite3 *db;                   /* The database connection */
  int nVar;                      /* Number of parameters */
  int nMem;                      /* Number of VM memory registers */
  int nCursor;                   /* Number of cursors required */
  int nArg;                      /* Max number args to xFilter or xUpdate */
  int n;                         /* Loop counter */
  struct ReusableSpace x;        /* Reusable bulk memory */

  assert( p!=0 );
  assert( p->nOp>0 );
  assert( pParse!=0 );
  assert( p->eVdbeState==VDBE_INIT_STATE );
  assert( pParse==p->pParse );
  assert( pParse->db==p->db );
  p->pVList = pParse->pVList;
  pParse->pVList =  0;
  db = p->db;
  assert( db->mallocFailed==0 );
  nVar = pParse->nVar;
  nMem = pParse->nMem;
  nCursor = pParse->nTab;
  nArg = pParse->nMaxArg;

  /* Each cursor uses a memory cell.  The first cursor (cursor 0) can
  ** use aMem[0] which is not otherwise used by the VDBE program.  Allocate
  ** space at the end of aMem[] for cursors 1 and greater.
  ** See also: allocateCursor().
  */
  nMem += nCursor;
  if( nCursor==0 && nMem>0 ) nMem++;  /* Space for aMem[0] even if not used */

  /* Figure out how much reusable memory is available at the end of the
  ** opcode array.  This extra memory will be reallocated for other elements
  ** of the prepared statement.
  */
  n = ROUND8P(sizeof(Op)*p->nOp);             /* Bytes of opcode memory used */
  x.pSpace = &((u8*)p->aOp)[n];               /* Unused opcode memory */
  assert( EIGHT_BYTE_ALIGNMENT(x.pSpace) );
  x.nFree = ROUNDDOWN8(pParse->szOpAlloc - n);  /* Bytes of unused memory */
  assert( x.nFree>=0 );
  assert( EIGHT_BYTE_ALIGNMENT(&x.pSpace[x.nFree]) );

  resolveP2Values(p, &nArg);
  p->usesStmtJournal = (u8)(pParse->isMultiWrite && pParse->mayAbort);
  if( pParse->explain ){
    if( nMem<10 ) nMem = 10;
    p->explain = pParse->explain;
    p->nResColumn = 12 - 4*p->explain;
  }
  p->expired = 0;

  /* Memory for registers, parameters, cursor, etc, is allocated in one or two
  ** passes.  On the first pass, we try to reuse unused memory at the
  ** end of the opcode array.  If we are unable to satisfy all memory
  ** requirements by reusing the opcode array tail, then the second
  ** pass will fill in the remainder using a fresh memory allocation.
  **
  ** This two-pass approach that reuses as much memory as possible from
  ** the leftover memory at the end of the opcode array.  This can significantly
  ** reduce the amount of memory held by a prepared statement.
  */
  x.nNeeded = 0;
  p->aMem = allocSpace(&x, 0, nMem*sizeof(Mem));
  p->aVar = allocSpace(&x, 0, nVar*sizeof(Mem));
  p->apArg = allocSpace(&x, 0, nArg*sizeof(Mem*));
  p->apCsr = allocSpace(&x, 0, nCursor*sizeof(VdbeCursor*));
  if( x.nNeeded ){
    x.pSpace = p->pFree = sqlite3DbMallocRawNN(db, x.nNeeded);
    x.nFree = x.nNeeded;
    if( !db->mallocFailed ){
      p->aMem = allocSpace(&x, p->aMem, nMem*sizeof(Mem));
      p->aVar = allocSpace(&x, p->aVar, nVar*sizeof(Mem));
      p->apArg = allocSpace(&x, p->apArg, nArg*sizeof(Mem*));
      p->apCsr = allocSpace(&x, p->apCsr, nCursor*sizeof(VdbeCursor*));
    }
  }
#ifdef SQLITE_DEBUG
  p->napArg = nArg;
#endif

  if( db->mallocFailed ){
    p->nVar = 0;
    p->nCursor = 0;
    p->nMem = 0;
  }else{
    p->nCursor = nCursor;
    p->nVar = (ynVar)nVar;
    initMemArray(p->aVar, nVar, db, MEM_Null);
    p->nMem = nMem;
    initMemArray(p->aMem, nMem, db, MEM_Undefined);
    memset(p->apCsr, 0, nCursor*sizeof(VdbeCursor*));
  }
  sqlite3VdbeRewind(p);
}

/*
** Close a VDBE cursor and release all the resources that cursor
** happens to hold.
*/
SQLITE_PRIVATE void sqlite3VdbeFreeCursor(Vdbe *p, VdbeCursor *pCx){
  if( pCx ) sqlite3VdbeFreeCursorNN(p,pCx);
}
static SQLITE_NOINLINE void freeCursorWithCache(Vdbe *p, VdbeCursor *pCx){
  VdbeTxtBlbCache *pCache = pCx->pCache;
  assert( pCx->colCache );
  pCx->colCache = 0;
  pCx->pCache = 0;
  if( pCache->pCValue ){
    sqlite3RCStrUnref(pCache->pCValue);
    pCache->pCValue = 0;
  }
  sqlite3DbFree(p->db, pCache);
  sqlite3VdbeFreeCursorNN(p, pCx);
}
SQLITE_PRIVATE void sqlite3VdbeFreeCursorNN(Vdbe *p, VdbeCursor *pCx){
  if( pCx->colCache ){
    freeCursorWithCache(p, pCx);
    return;
  }
  switch( pCx->eCurType ){
    case CURTYPE_SORTER: {
      sqlite3VdbeSorterClose(p->db, pCx);
      break;
    }
    case CURTYPE_BTREE: {
      assert( pCx->uc.pCursor!=0 );
      sqlite3BtreeCloseCursor(pCx->uc.pCursor);
      break;
    }
#ifndef SQLITE_OMIT_VIRTUALTABLE
    case CURTYPE_VTAB: {
      sqlite3_vtab_cursor *pVCur = pCx->uc.pVCur;
      const sqlite3_module *pModule = pVCur->pVtab->pModule;
      assert( pVCur->pVtab->nRef>0 );
      pVCur->pVtab->nRef--;
      pModule->xClose(pVCur);
      break;
    }
#endif
  }
}

/*
** Close all cursors in the current frame.
*/
static void closeCursorsInFrame(Vdbe *p){
  int i;
  for(i=0; i<p->nCursor; i++){
    VdbeCursor *pC = p->apCsr[i];
    if( pC ){
      sqlite3VdbeFreeCursorNN(p, pC);
      p->apCsr[i] = 0;
    }
  }
}

/*
** Copy the values stored in the VdbeFrame structure to its Vdbe. This
** is used, for example, when a trigger sub-program is halted to restore
** control to the main program.
*/
SQLITE_PRIVATE int sqlite3VdbeFrameRestore(VdbeFrame *pFrame){
  Vdbe *v = pFrame->v;
  closeCursorsInFrame(v);
  v->aOp = pFrame->aOp;
  v->nOp = pFrame->nOp;
  v->aMem = pFrame->aMem;
  v->nMem = pFrame->nMem;
  v->apCsr = pFrame->apCsr;
  v->nCursor = pFrame->nCursor;
  v->db->lastRowid = pFrame->lastRowid;
  v->nChange = pFrame->nChange;
  v->db->nChange = pFrame->nDbChange;
  sqlite3VdbeDeleteAuxData(v->db, &v->pAuxData, -1, 0);
  v->pAuxData = pFrame->pAuxData;
  pFrame->pAuxData = 0;
  return pFrame->pc;
}

/*
** Close all cursors.
**
** Also release any dynamic memory held by the VM in the Vdbe.aMem memory
** cell array. This is necessary as the memory cell array may contain
** pointers to VdbeFrame objects, which may in turn contain pointers to
** open cursors.
*/
static void closeAllCursors(Vdbe *p){
  if( p->pFrame ){
    VdbeFrame *pFrame;
    for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
    sqlite3VdbeFrameRestore(pFrame);
    p->pFrame = 0;
    p->nFrame = 0;
  }
  assert( p->nFrame==0 );
  closeCursorsInFrame(p);
  releaseMemArray(p->aMem, p->nMem);
  while( p->pDelFrame ){
    VdbeFrame *pDel = p->pDelFrame;
    p->pDelFrame = pDel->pParent;
    sqlite3VdbeFrameDelete(pDel);
  }

  /* Delete any auxdata allocations made by the VM */
  if( p->pAuxData ) sqlite3VdbeDeleteAuxData(p->db, &p->pAuxData, -1, 0);
  assert( p->pAuxData==0 );
}

/*
** Set the number of result columns that will be returned by this SQL
** statement. This is now set at compile time, rather than during
** execution of the vdbe program so that sqlite3_column_count() can
** be called on an SQL statement before sqlite3_step().
*/
SQLITE_PRIVATE void sqlite3VdbeSetNumCols(Vdbe *p, int nResColumn){
  int n;
  sqlite3 *db = p->db;

  if( p->nResAlloc ){
    releaseMemArray(p->aColName, p->nResAlloc*COLNAME_N);
    sqlite3DbFree(db, p->aColName);
  }
  n = nResColumn*COLNAME_N;
  p->nResColumn = p->nResAlloc = (u16)nResColumn;
  p->aColName = (Mem*)sqlite3DbMallocRawNN(db, sizeof(Mem)*n );
  if( p->aColName==0 ) return;
  initMemArray(p->aColName, n, db, MEM_Null);
}

/*
** Set the name of the idx'th column to be returned by the SQL statement.
** zName must be a pointer to a nul terminated string.
**
** This call must be made after a call to sqlite3VdbeSetNumCols().
**
** The final parameter, xDel, must be one of SQLITE_DYNAMIC, SQLITE_STATIC
** or SQLITE_TRANSIENT. If it is SQLITE_DYNAMIC, then the buffer pointed
** to by zName will be freed by sqlite3DbFree() when the vdbe is destroyed.
*/
SQLITE_PRIVATE int sqlite3VdbeSetColName(
  Vdbe *p,                         /* Vdbe being configured */
  int idx,                         /* Index of column zName applies to */
  int var,                         /* One of the COLNAME_* constants */
  const char *zName,               /* Pointer to buffer containing name */
  void (*xDel)(void*)              /* Memory management strategy for zName */

sqlite3.c  view on Meta::CPAN

  assert( p->db==0 || p->db==db );
  if( p->aColName ){
    releaseMemArray(p->aColName, p->nResAlloc*COLNAME_N);
    sqlite3DbNNFreeNN(db, p->aColName);
  }
  for(pSub=p->pProgram; pSub; pSub=pNext){
    pNext = pSub->pNext;
    vdbeFreeOpArray(db, pSub->aOp, pSub->nOp);
    sqlite3DbFree(db, pSub);
  }
  if( p->eVdbeState!=VDBE_INIT_STATE ){
    releaseMemArray(p->aVar, p->nVar);
    if( p->pVList ) sqlite3DbNNFreeNN(db, p->pVList);
    if( p->pFree ) sqlite3DbNNFreeNN(db, p->pFree);
  }
  vdbeFreeOpArray(db, p->aOp, p->nOp);
  if( p->zSql ) sqlite3DbNNFreeNN(db, p->zSql);
#ifdef SQLITE_ENABLE_NORMALIZE
  sqlite3DbFree(db, p->zNormSql);
  {
    DblquoteStr *pThis, *pNxt;
    for(pThis=p->pDblStr; pThis; pThis=pNxt){
      pNxt = pThis->pNextStr;
      sqlite3DbFree(db, pThis);
    }
  }
#endif
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
  {
    int i;
    for(i=0; i<p->nScan; i++){
      sqlite3DbFree(db, p->aScan[i].zName);
    }
    sqlite3DbFree(db, p->aScan);
  }
#endif
}

/*
** Delete an entire VDBE.
*/
SQLITE_PRIVATE void sqlite3VdbeDelete(Vdbe *p){
  sqlite3 *db;

  assert( p!=0 );
  db = p->db;
  assert( db!=0 );
  assert( sqlite3_mutex_held(db->mutex) );
  sqlite3VdbeClearObject(db, p);
  if( db->pnBytesFreed==0 ){
    assert( p->ppVPrev!=0 );
    *p->ppVPrev = p->pVNext;
    if( p->pVNext ){
      p->pVNext->ppVPrev = p->ppVPrev;
    }
  }
  sqlite3DbNNFreeNN(db, p);
}

/*
** The cursor "p" has a pending seek operation that has not yet been
** carried out.  Seek the cursor now.  If an error occurs, return
** the appropriate error code.
*/
SQLITE_PRIVATE int SQLITE_NOINLINE sqlite3VdbeFinishMoveto(VdbeCursor *p){
  int res, rc;
#ifdef SQLITE_TEST
  extern int sqlite3_search_count;
#endif
  assert( p->deferredMoveto );
  assert( p->isTable );
  assert( p->eCurType==CURTYPE_BTREE );
  rc = sqlite3BtreeTableMoveto(p->uc.pCursor, p->movetoTarget, 0, &res);
  if( rc ) return rc;
  if( res!=0 ) return SQLITE_CORRUPT_BKPT;
#ifdef SQLITE_TEST
  sqlite3_search_count++;
#endif
  p->deferredMoveto = 0;
  p->cacheStatus = CACHE_STALE;
  return SQLITE_OK;
}

/*
** Something has moved cursor "p" out of place.  Maybe the row it was
** pointed to was deleted out from under it.  Or maybe the btree was
** rebalanced.  Whatever the cause, try to restore "p" to the place it
** is supposed to be pointing.  If the row was deleted out from under the
** cursor, set the cursor to point to a NULL row.
*/
SQLITE_PRIVATE int SQLITE_NOINLINE sqlite3VdbeHandleMovedCursor(VdbeCursor *p){
  int isDifferentRow, rc;
  assert( p->eCurType==CURTYPE_BTREE );
  assert( p->uc.pCursor!=0 );
  assert( sqlite3BtreeCursorHasMoved(p->uc.pCursor) );
  rc = sqlite3BtreeCursorRestore(p->uc.pCursor, &isDifferentRow);
  p->cacheStatus = CACHE_STALE;
  if( isDifferentRow ) p->nullRow = 1;
  return rc;
}

/*
** Check to ensure that the cursor is valid.  Restore the cursor
** if need be.  Return any I/O error from the restore operation.
*/
SQLITE_PRIVATE int sqlite3VdbeCursorRestore(VdbeCursor *p){
  assert( p->eCurType==CURTYPE_BTREE || IsNullCursor(p) );
  if( sqlite3BtreeCursorHasMoved(p->uc.pCursor) ){
    return sqlite3VdbeHandleMovedCursor(p);
  }
  return SQLITE_OK;
}

/*
** The following functions:
**
** sqlite3VdbeSerialType()
** sqlite3VdbeSerialTypeLen()
** sqlite3VdbeSerialLen()
** sqlite3VdbeSerialPut()  <--- in-lined into OP_MakeRecord as of 2022-04-02
** sqlite3VdbeSerialGet()
**
** encapsulate the code that serializes values for storage in SQLite
** data and index records. Each serialized value consists of a
** 'serial-type' and a blob of data. The serial type is an 8-byte unsigned
** integer, stored as a varint.
**
** In an SQLite index record, the serial type is stored directly before
** the blob of data that it corresponds to. In a table record, all serial
** types are stored at the start of the record, and the blobs of data at
** the end. Hence these functions allow the caller to handle the
** serial-type and data blob separately.
**
** The following table describes the various storage classes for data:
**
**   serial type        bytes of data      type
**   --------------     ---------------    ---------------
**      0                     0            NULL
**      1                     1            signed integer
**      2                     2            signed integer
**      3                     3            signed integer
**      4                     4            signed integer
**      5                     6            signed integer
**      6                     8            signed integer
**      7                     8            IEEE float
**      8                     0            Integer constant 0
**      9                     0            Integer constant 1
**     10,11                               reserved for expansion
**    N>=12 and even       (N-12)/2        BLOB
**    N>=13 and odd        (N-13)/2        text
**
** The 8 and 9 types were added in 3.3.0, file format 4.  Prior versions
** of SQLite will not understand those serial types.
*/

#if 0 /* Inlined into the OP_MakeRecord opcode */
/*
** Return the serial-type for the value stored in pMem.
**
** This routine might convert a large MEM_IntReal value into MEM_Real.
**
** 2019-07-11:  The primary user of this subroutine was the OP_MakeRecord
** opcode in the byte-code engine.  But by moving this routine in-line, we

sqlite3.c  view on Meta::CPAN

  ** than 2GiB are support - anything large must be database corruption.
  ** Any corruption is detected in sqlite3BtreeParseCellPtr(), though, so
  ** this code can safely assume that nCellKey is 32-bits
  */
  assert( sqlite3BtreeCursorIsValid(pCur) );
  nCellKey = sqlite3BtreePayloadSize(pCur);
  assert( (nCellKey & SQLITE_MAX_U32)==(u64)nCellKey );

  /* Read in the complete content of the index entry */
  sqlite3VdbeMemInit(&m, db, 0);
  rc = sqlite3VdbeMemFromBtreeZeroOffset(pCur, (u32)nCellKey, &m);
  if( rc ){
    return rc;
  }

  /* The index entry must begin with a header size */
  getVarint32NR((u8*)m.z, szHdr);
  testcase( szHdr==3 );
  testcase( szHdr==(u32)m.n );
  testcase( szHdr>0x7fffffff );
  assert( m.n>=0 );
  if( unlikely(szHdr<3 || szHdr>(unsigned)m.n) ){
    goto idx_rowid_corruption;
  }

  /* The last field of the index should be an integer - the ROWID.
  ** Verify that the last entry really is an integer. */
  getVarint32NR((u8*)&m.z[szHdr-1], typeRowid);
  testcase( typeRowid==1 );
  testcase( typeRowid==2 );
  testcase( typeRowid==3 );
  testcase( typeRowid==4 );
  testcase( typeRowid==5 );
  testcase( typeRowid==6 );
  testcase( typeRowid==8 );
  testcase( typeRowid==9 );
  if( unlikely(typeRowid<1 || typeRowid>9 || typeRowid==7) ){
    goto idx_rowid_corruption;
  }
  lenRowid = sqlite3SmallTypeSizes[typeRowid];
  testcase( (u32)m.n==szHdr+lenRowid );
  if( unlikely((u32)m.n<szHdr+lenRowid) ){
    goto idx_rowid_corruption;
  }

  /* Fetch the integer off the end of the index record */
  sqlite3VdbeSerialGet((u8*)&m.z[m.n-lenRowid], typeRowid, &v);
  *rowid = v.u.i;
  sqlite3VdbeMemReleaseMalloc(&m);
  return SQLITE_OK;

  /* Jump here if database corruption is detected after m has been
  ** allocated.  Free the m object and return SQLITE_CORRUPT. */
idx_rowid_corruption:
  testcase( m.szMalloc!=0 );
  sqlite3VdbeMemReleaseMalloc(&m);
  return SQLITE_CORRUPT_BKPT;
}

/*
** Compare the key of the index entry that cursor pC is pointing to against
** the key string in pUnpacked.  Write into *pRes a number
** that is negative, zero, or positive if pC is less than, equal to,
** or greater than pUnpacked.  Return SQLITE_OK on success.
**
** pUnpacked is either created without a rowid or is truncated so that it
** omits the rowid at the end.  The rowid at the end of the index entry
** is ignored as well.  Hence, this routine only compares the prefixes
** of the keys prior to the final rowid, not the entire key.
*/
SQLITE_PRIVATE int sqlite3VdbeIdxKeyCompare(
  sqlite3 *db,                     /* Database connection */
  VdbeCursor *pC,                  /* The cursor to compare against */
  UnpackedRecord *pUnpacked,       /* Unpacked version of key */
  int *res                         /* Write the comparison result here */
){
  i64 nCellKey = 0;
  int rc;
  BtCursor *pCur;
  Mem m;

  assert( pC->eCurType==CURTYPE_BTREE );
  pCur = pC->uc.pCursor;
  assert( sqlite3BtreeCursorIsValid(pCur) );
  nCellKey = sqlite3BtreePayloadSize(pCur);
  /* nCellKey will always be between 0 and 0xffffffff because of the way
  ** that btreeParseCellPtr() and sqlite3GetVarint32() are implemented */
  if( nCellKey<=0 || nCellKey>0x7fffffff ){
    *res = 0;
    return SQLITE_CORRUPT_BKPT;
  }
  sqlite3VdbeMemInit(&m, db, 0);
  rc = sqlite3VdbeMemFromBtreeZeroOffset(pCur, (u32)nCellKey, &m);
  if( rc ){
    return rc;
  }
  *res = sqlite3VdbeRecordCompareWithSkip(m.n, m.z, pUnpacked, 0);
  sqlite3VdbeMemReleaseMalloc(&m);
  return SQLITE_OK;
}

/*
** This routine sets the value to be returned by subsequent calls to
** sqlite3_changes() on the database handle 'db'.
*/
SQLITE_PRIVATE void sqlite3VdbeSetChanges(sqlite3 *db, i64 nChange){
  assert( sqlite3_mutex_held(db->mutex) );
  db->nChange = nChange;
  db->nTotalChange += nChange;
}

/*
** Set a flag in the vdbe to update the change counter when it is finalised
** or reset.
*/
SQLITE_PRIVATE void sqlite3VdbeCountChanges(Vdbe *v){
  v->changeCntOn = 1;
}

/*
** Mark every prepared statement associated with a database connection
** as expired.
**
** An expired statement means that recompilation of the statement is
** recommend.  Statements expire when things happen that make their
** programs obsolete.  Removing user-defined functions or collating
** sequences, or changing an authorization function are the types of
** things that make prepared statements obsolete.
**
** If iCode is 1, then expiration is advisory.  The statement should
** be reprepared before being restarted, but if it is already running
** it is allowed to run to completion.
**

sqlite3.c  view on Meta::CPAN

}
#endif /* SQLITE_OMIT_DATETIME_FUNCS */

#if defined(SQLITE_ENABLE_CURSOR_HINTS) && defined(SQLITE_DEBUG)
/*
** This Walker callback is used to help verify that calls to
** sqlite3BtreeCursorHint() with opcode BTREE_HINT_RANGE have
** byte-code register values correctly initialized.
*/
SQLITE_PRIVATE int sqlite3CursorRangeHintExprCheck(Walker *pWalker, Expr *pExpr){
  if( pExpr->op==TK_REGISTER ){
    assert( (pWalker->u.aMem[pExpr->iTable].flags & MEM_Undefined)==0 );
  }
  return WRC_Continue;
}
#endif /* SQLITE_ENABLE_CURSOR_HINTS && SQLITE_DEBUG */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/*
** Transfer error message text from an sqlite3_vtab.zErrMsg (text stored
** in memory obtained from sqlite3_malloc) into a Vdbe.zErrMsg (text stored
** in memory obtained from sqlite3DbMalloc).
*/
SQLITE_PRIVATE void sqlite3VtabImportErrmsg(Vdbe *p, sqlite3_vtab *pVtab){
  if( pVtab->zErrMsg ){
    sqlite3 *db = p->db;
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = sqlite3DbStrDup(db, pVtab->zErrMsg);
    sqlite3_free(pVtab->zErrMsg);
    pVtab->zErrMsg = 0;
  }
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifdef SQLITE_ENABLE_PREUPDATE_HOOK

/*
** If the second argument is not NULL, release any allocations associated
** with the memory cells in the p->aMem[] array. Also free the UnpackedRecord
** structure itself, using sqlite3DbFree().
**
** This function is used to free UnpackedRecord structures allocated by
** the vdbeUnpackRecord() function found in vdbeapi.c.
*/
static void vdbeFreeUnpacked(sqlite3 *db, int nField, UnpackedRecord *p){
  assert( db!=0 );
  if( p ){
    int i;
    for(i=0; i<nField; i++){
      Mem *pMem = &p->aMem[i];
      if( pMem->zMalloc ) sqlite3VdbeMemReleaseMalloc(pMem);
    }
    sqlite3DbNNFreeNN(db, p);
  }
}
#endif /* SQLITE_ENABLE_PREUPDATE_HOOK */

#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
/*
** Invoke the pre-update hook. If this is an UPDATE or DELETE pre-update call,
** then cursor passed as the second argument should point to the row about
** to be update or deleted. If the application calls sqlite3_preupdate_old(),
** the required value will be read from the row the cursor points to.
*/
SQLITE_PRIVATE void sqlite3VdbePreUpdateHook(
  Vdbe *v,                        /* Vdbe pre-update hook is invoked by */
  VdbeCursor *pCsr,               /* Cursor to grab old.* values from */
  int op,                         /* SQLITE_INSERT, UPDATE or DELETE */
  const char *zDb,                /* Database name */
  Table *pTab,                    /* Modified table */
  i64 iKey1,                      /* Initial key value */
  int iReg,                       /* Register for new.* record */
  int iBlobWrite
){
  sqlite3 *db = v->db;
  i64 iKey2;
  PreUpdate preupdate;
  const char *zTbl = pTab->zName;
#ifdef SQLITE_DEBUG
  int nRealCol;
  if( pTab->tabFlags & TF_WithoutRowid ){
    nRealCol = sqlite3PrimaryKeyIndex(pTab)->nColumn;
  }else if( pTab->tabFlags & TF_HasVirtual ){
    nRealCol = pTab->nNVCol;
  }else{
    nRealCol = pTab->nCol;
  }
#endif

  assert( db->pPreUpdate==0 );
  memset(&preupdate, 0, sizeof(PreUpdate));
  if( HasRowid(pTab)==0 ){
    iKey1 = iKey2 = 0;
    preupdate.pPk = sqlite3PrimaryKeyIndex(pTab);
  }else{
    if( op==SQLITE_UPDATE ){
      iKey2 = v->aMem[iReg].u.i;
    }else{
      iKey2 = iKey1;
    }
  }

  assert( pCsr!=0 );
  assert( pCsr->eCurType==CURTYPE_BTREE );
  assert( pCsr->nField==nRealCol
       || (pCsr->nField==nRealCol+1 && op==SQLITE_DELETE && iReg==-1)
  );

  preupdate.v = v;
  preupdate.pCsr = pCsr;
  preupdate.op = op;
  preupdate.iNewReg = iReg;
  preupdate.pKeyinfo = (KeyInfo*)&preupdate.uKey;
  preupdate.pKeyinfo->db = db;
  preupdate.pKeyinfo->enc = ENC(db);
  preupdate.pKeyinfo->nKeyField = pTab->nCol;
  preupdate.pKeyinfo->aSortFlags = 0; /* Indicate .aColl, .nAllField uninit */
  preupdate.iKey1 = iKey1;
  preupdate.iKey2 = iKey2;
  preupdate.pTab = pTab;
  preupdate.iBlobWrite = iBlobWrite;

  db->pPreUpdate = &preupdate;

sqlite3.c  view on Meta::CPAN


#elif !defined(__STRICT_ANSI__) && (defined(__GNUC__) && defined(__x86_64__))

  __inline__ sqlite_uint64 sqlite3Hwtime(void){
     unsigned int lo, hi;
     __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));
     return (sqlite_uint64)hi << 32 | lo;
  }

#elif !defined(__STRICT_ANSI__) && (defined(__GNUC__) && defined(__ppc__))

  __inline__ sqlite_uint64 sqlite3Hwtime(void){
      unsigned long long retval;
      unsigned long junk;
      __asm__ __volatile__ ("\n\
          1:      mftbu   %1\n\
                  mftb    %L0\n\
                  mftbu   %0\n\
                  cmpw    %0,%1\n\
                  bne     1b"
                  : "=r" (retval), "=r" (junk));
      return retval;
  }

#else

  /*
  ** asm() is needed for hardware timing support.  Without asm(),
  ** disable the sqlite3Hwtime() routine.
  **
  ** sqlite3Hwtime() is only used for some obscure debugging
  ** and analysis configurations, not in any deliverable, so this
  ** should not be a great loss.
  */
SQLITE_PRIVATE   sqlite_uint64 sqlite3Hwtime(void){ return ((sqlite_uint64)0); }

#endif

#endif /* !defined(SQLITE_HWTIME_H) */

/************** End of hwtime.h **********************************************/
/************** Continuing where we left off in vdbe.c ***********************/
#endif

/*
** Invoke this macro on memory cells just prior to changing the
** value of the cell.  This macro verifies that shallow copies are
** not misused.  A shallow copy of a string or blob just copies a
** pointer to the string or blob, not the content.  If the original
** is changed while the copy is still in use, the string or blob might
** be changed out from under the copy.  This macro verifies that nothing
** like that ever happens.
*/
#ifdef SQLITE_DEBUG
# define memAboutToChange(P,M) sqlite3VdbeMemAboutToChange(P,M)
#else
# define memAboutToChange(P,M)
#endif

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test
** procedures use this information to make sure that indices are
** working correctly.  This variable has no function other than to
** help verify the correct operation of the library.
*/
#ifdef SQLITE_TEST
SQLITE_API int sqlite3_search_count = 0;
#endif

/*
** When this global variable is positive, it gets decremented once before
** each instruction in the VDBE.  When it reaches zero, the u1.isInterrupted
** field of the sqlite3 structure is set in order to simulate an interrupt.
**
** This facility is used for testing purposes only.  It does not function
** in an ordinary build.
*/
#ifdef SQLITE_TEST
SQLITE_API int sqlite3_interrupt_count = 0;
#endif

/*
** The next global variable is incremented each type the OP_Sort opcode
** is executed.  The test procedures use this information to make sure that
** sorting is occurring or not occurring at appropriate times.   This variable
** has no function other than to help verify the correct operation of the
** library.
*/
#ifdef SQLITE_TEST
SQLITE_API int sqlite3_sort_count = 0;
#endif

/*
** The next global variable records the size of the largest MEM_Blob
** or MEM_Str that has been used by a VDBE opcode.  The test procedures
** use this information to make sure that the zero-blob functionality
** is working correctly.   This variable has no function other than to
** help verify the correct operation of the library.
*/
#ifdef SQLITE_TEST
SQLITE_API int sqlite3_max_blobsize = 0;
static void updateMaxBlobsize(Mem *p){
  if( (p->flags & (MEM_Str|MEM_Blob))!=0 && p->n>sqlite3_max_blobsize ){
    sqlite3_max_blobsize = p->n;
  }
}
#endif

/*
** This macro evaluates to true if either the update hook or the preupdate
** hook are enabled for database connect DB.
*/
#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
# define HAS_UPDATE_HOOK(DB) ((DB)->xPreUpdateCallback||(DB)->xUpdateCallback)
#else
# define HAS_UPDATE_HOOK(DB) ((DB)->xUpdateCallback)
#endif

/*
** The next global variable is incremented each time the OP_Found opcode

sqlite3.c  view on Meta::CPAN

** Since only a line number is retained, not the filename, this macro
** only works for amalgamation builds.  But that is ok, since these macros
** should be no-ops except for special builds used to measure test coverage.
*/
#if !defined(SQLITE_VDBE_COVERAGE)
# define VdbeBranchTaken(I,M)
#else
# define VdbeBranchTaken(I,M) vdbeTakeBranch(pOp->iSrcLine,I,M)
  static void vdbeTakeBranch(u32 iSrcLine, u8 I, u8 M){
    u8 mNever;
    assert( I<=2 );  /* 0: fall through,  1: taken,  2: alternate taken */
    assert( M<=4 );  /* 2: two-way branch, 3: three-way branch, 4: OP_Jump */
    assert( I<M );   /* I can only be 2 if M is 3 or 4 */
    /* Transform I from a integer [0,1,2] into a bitmask of [1,2,4] */
    I = 1<<I;
    /* The upper 8 bits of iSrcLine are flags.  The lower three bits of
    ** the flags indicate directions that the branch can never go.  If
    ** a branch really does go in one of those directions, assert right
    ** away. */
    mNever = iSrcLine >> 24;
    assert( (I & mNever)==0 );
    if( sqlite3GlobalConfig.xVdbeBranch==0 ) return;  /*NO_TEST*/
    /* Invoke the branch coverage callback with three arguments:
    **    iSrcLine - the line number of the VdbeCoverage() macro, with
    **               flags removed.
    **    I        - Mask of bits 0x07 indicating which cases are are
    **               fulfilled by this instance of the jump.  0x01 means
    **               fall-thru, 0x02 means taken, 0x04 means NULL.  Any
    **               impossible cases (ex: if the comparison is never NULL)
    **               are filled in automatically so that the coverage
    **               measurement logic does not flag those impossible cases
    **               as missed coverage.
    **    M        - Type of jump.  Same as M argument above
    */
    I |= mNever;
    if( M==2 ) I |= 0x04;
    if( M==4 ){
      I |= 0x08;
      if( (mNever&0x08)!=0 && (I&0x05)!=0) I |= 0x05; /*NO_TEST*/
    }
    sqlite3GlobalConfig.xVdbeBranch(sqlite3GlobalConfig.pVdbeBranchArg,
                                    iSrcLine&0xffffff, I, M);
  }
#endif

/*
** An ephemeral string value (signified by the MEM_Ephem flag) contains
** a pointer to a dynamically allocated string where some other entity
** is responsible for deallocating that string.  Because the register
** does not control the string, it might be deleted without the register
** knowing it.
**
** This routine converts an ephemeral string into a dynamically allocated
** string that the register itself controls.  In other words, it
** converts an MEM_Ephem string into a string with P.z==P.zMalloc.
*/
#define Deephemeralize(P) \
   if( ((P)->flags&MEM_Ephem)!=0 \
       && sqlite3VdbeMemMakeWriteable(P) ){ goto no_mem;}

/* Return true if the cursor was opened using the OP_OpenSorter opcode. */
#define isSorter(x) ((x)->eCurType==CURTYPE_SORTER)

/*
** Allocate VdbeCursor number iCur.  Return a pointer to it.  Return NULL
** if we run out of memory.
*/
static VdbeCursor *allocateCursor(
  Vdbe *p,              /* The virtual machine */
  int iCur,             /* Index of the new VdbeCursor */
  int nField,           /* Number of fields in the table or index */
  u8 eCurType           /* Type of the new cursor */
){
  /* Find the memory cell that will be used to store the blob of memory
  ** required for this VdbeCursor structure. It is convenient to use a
  ** vdbe memory cell to manage the memory allocation required for a
  ** VdbeCursor structure for the following reasons:
  **
  **   * Sometimes cursor numbers are used for a couple of different
  **     purposes in a vdbe program. The different uses might require
  **     different sized allocations. Memory cells provide growable
  **     allocations.
  **
  **   * When using ENABLE_MEMORY_MANAGEMENT, memory cell buffers can
  **     be freed lazily via the sqlite3_release_memory() API. This
  **     minimizes the number of malloc calls made by the system.
  **
  ** The memory cell for cursor 0 is aMem[0]. The rest are allocated from
  ** the top of the register space.  Cursor 1 is at Mem[p->nMem-1].
  ** Cursor 2 is at Mem[p->nMem-2]. And so forth.
  */
  Mem *pMem = iCur>0 ? &p->aMem[p->nMem-iCur] : p->aMem;

  i64 nByte;
  VdbeCursor *pCx = 0;
  nByte = SZ_VDBECURSOR(nField);
  assert( ROUND8(nByte)==nByte );
  if( eCurType==CURTYPE_BTREE ) nByte += sqlite3BtreeCursorSize();

  assert( iCur>=0 && iCur<p->nCursor );
  if( p->apCsr[iCur] ){ /*OPTIMIZATION-IF-FALSE*/
    sqlite3VdbeFreeCursorNN(p, p->apCsr[iCur]);
    p->apCsr[iCur] = 0;
  }

  /* There used to be a call to sqlite3VdbeMemClearAndResize() to make sure
  ** the pMem used to hold space for the cursor has enough storage available
  ** in pMem->zMalloc.  But for the special case of the aMem[] entries used
  ** to hold cursors, it is faster to in-line the logic. */
  assert( pMem->flags==MEM_Undefined );
  assert( (pMem->flags & MEM_Dyn)==0 );
  assert( pMem->szMalloc==0 || pMem->z==pMem->zMalloc );
  if( pMem->szMalloc<nByte ){
    if( pMem->szMalloc>0 ){
      sqlite3DbFreeNN(pMem->db, pMem->zMalloc);
    }
    pMem->z = pMem->zMalloc = sqlite3DbMallocRaw(pMem->db, nByte);
    if( pMem->zMalloc==0 ){
      pMem->szMalloc = 0;
      return 0;
    }
    pMem->szMalloc = (int)nByte;
  }

  p->apCsr[iCur] = pCx = (VdbeCursor*)pMem->zMalloc;
  memset(pCx, 0, offsetof(VdbeCursor,pAltCursor));
  pCx->eCurType = eCurType;
  pCx->nField = nField;
  pCx->aOffset = &pCx->aType[nField];
  if( eCurType==CURTYPE_BTREE ){
    assert( ROUND8(SZ_VDBECURSOR(nField))==SZ_VDBECURSOR(nField) );
    pCx->uc.pCursor = (BtCursor*)&pMem->z[SZ_VDBECURSOR(nField)];
    sqlite3BtreeCursorZero(pCx->uc.pCursor);
  }
  return pCx;
}

/*
** The string in pRec is known to look like an integer and to have a
** floating point value of rValue.  Return true and set *piValue to the
** integer value if the string is in range to be an integer.  Otherwise,
** return false.
*/
static int alsoAnInt(Mem *pRec, double rValue, i64 *piValue){
  i64 iValue;
  iValue = sqlite3RealToI64(rValue);
  if( sqlite3RealSameAsInt(rValue,iValue) ){
    *piValue = iValue;
    return 1;
  }
  return 0==sqlite3Atoi64(pRec->z, piValue, pRec->n, pRec->enc);
}

/*
** Try to convert a value into a numeric representation if we can
** do so without loss of information.  In other words, if the string
** looks like a number, convert it into a number.  If it does not
** look like a number, leave it alone.
**
** If the bTryForInt flag is true, then extra effort is made to give
** an integer representation.  Strings that look like floating point
** values but which have no fractional component (example: '48.00')
** will have a MEM_Int representation when bTryForInt is true.
**
** If bTryForInt is false, then if the input string contains a decimal
** point or exponential notation, the result is only MEM_Real, even
** if there is an exact integer representation of the quantity.
*/
static void applyNumericAffinity(Mem *pRec, int bTryForInt){

sqlite3.c  view on Meta::CPAN

}
#endif

/*
** Return the register of pOp->p2 after first preparing it to be
** overwritten with an integer value.
*/
static SQLITE_NOINLINE Mem *out2PrereleaseWithClear(Mem *pOut){
  sqlite3VdbeMemSetNull(pOut);
  pOut->flags = MEM_Int;
  return pOut;
}
static Mem *out2Prerelease(Vdbe *p, VdbeOp *pOp){
  Mem *pOut;
  assert( pOp->p2>0 );
  assert( pOp->p2<=(p->nMem+1 - p->nCursor) );
  pOut = &p->aMem[pOp->p2];
  memAboutToChange(p, pOut);
  if( VdbeMemDynamic(pOut) ){ /*OPTIMIZATION-IF-FALSE*/
    return out2PrereleaseWithClear(pOut);
  }else{
    pOut->flags = MEM_Int;
    return pOut;
  }
}

/*
** Compute a bloom filter hash using pOp->p4.i registers from aMem[] beginning
** with pOp->p3.  Return the hash.
*/
static u64 filterHash(const Mem *aMem, const Op *pOp){
  int i, mx;
  u64 h = 0;

  assert( pOp->p4type==P4_INT32 );
  for(i=pOp->p3, mx=i+pOp->p4.i; i<mx; i++){
    const Mem *p = &aMem[i];
    if( p->flags & (MEM_Int|MEM_IntReal) ){
      h += p->u.i;
    }else if( p->flags & MEM_Real ){
      h += sqlite3VdbeIntValue(p);
    }else if( p->flags & (MEM_Str|MEM_Blob) ){
      /* All strings have the same hash and all blobs have the same hash,
      ** though, at least, those hashes are different from each other and
      ** from NULL. */
      h += 4093 + (p->flags & (MEM_Str|MEM_Blob));
    }
  }
  return h;
}


/*
** For OP_Column, factor out the case where content is loaded from
** overflow pages, so that the code to implement this case is separate
** the common case where all content fits on the page.  Factoring out
** the code reduces register pressure and helps the common case
** to run faster.
*/
static SQLITE_NOINLINE int vdbeColumnFromOverflow(
  VdbeCursor *pC,       /* The BTree cursor from which we are reading */
  int iCol,             /* The column to read */
  u32 t,                /* The serial-type code for the column value */
  i64 iOffset,          /* Offset to the start of the content value */
  u32 cacheStatus,      /* Current Vdbe.cacheCtr value */
  u32 colCacheCtr,      /* Current value of the column cache counter */
  Mem *pDest            /* Store the value into this register. */
){
  int rc;
  sqlite3 *db = pDest->db;
  int encoding = pDest->enc;
  int len = sqlite3VdbeSerialTypeLen(t);
  assert( pC->eCurType==CURTYPE_BTREE );
  if( len>db->aLimit[SQLITE_LIMIT_LENGTH] ) return SQLITE_TOOBIG;
  if( len > 4000 && pC->pKeyInfo==0 ){
    /* Cache large column values that are on overflow pages using
    ** an RCStr (reference counted string) so that if they are reloaded,
    ** that do not have to be copied a second time.  The overhead of
    ** creating and managing the cache is such that this is only
    ** profitable for larger TEXT and BLOB values.
    **
    ** Only do this on table-btrees so that writes to index-btrees do not
    ** need to clear the cache.  This buys performance in the common case
    ** in exchange for generality.
    */
    VdbeTxtBlbCache *pCache;
    char *pBuf;
    if( pC->colCache==0 ){
      pC->pCache = sqlite3DbMallocZero(db, sizeof(VdbeTxtBlbCache) );
      if( pC->pCache==0 ) return SQLITE_NOMEM;
      pC->colCache = 1;
    }
    pCache = pC->pCache;
    if( pCache->pCValue==0
     || pCache->iCol!=iCol
     || pCache->cacheStatus!=cacheStatus
     || pCache->colCacheCtr!=colCacheCtr
     || pCache->iOffset!=sqlite3BtreeOffset(pC->uc.pCursor)
    ){
      if( pCache->pCValue ) sqlite3RCStrUnref(pCache->pCValue);
      pBuf = pCache->pCValue = sqlite3RCStrNew( len+3 );
      if( pBuf==0 ) return SQLITE_NOMEM;
      rc = sqlite3BtreePayload(pC->uc.pCursor, iOffset, len, pBuf);
      if( rc ) return rc;
      pBuf[len] = 0;
      pBuf[len+1] = 0;
      pBuf[len+2] = 0;
      pCache->iCol = iCol;
      pCache->cacheStatus = cacheStatus;
      pCache->colCacheCtr = colCacheCtr;
      pCache->iOffset = sqlite3BtreeOffset(pC->uc.pCursor);
    }else{
      pBuf = pCache->pCValue;
    }
    assert( t>=12 );
    sqlite3RCStrRef(pBuf);
    if( t&1 ){
      rc = sqlite3VdbeMemSetStr(pDest, pBuf, len, encoding,
                                sqlite3RCStrUnref);
      pDest->flags |= MEM_Term;
    }else{

sqlite3.c  view on Meta::CPAN

** See also: InitCoroutine
*/
case OP_EndCoroutine: {           /* in1 */
  VdbeOp *pCaller;
  pIn1 = &aMem[pOp->p1];
  assert( pIn1->flags==MEM_Int );
  assert( pIn1->u.i>=0 && pIn1->u.i<p->nOp );
  pCaller = &aOp[pIn1->u.i];
  assert( pCaller->opcode==OP_Yield );
  assert( pCaller->p2>=0 && pCaller->p2<p->nOp );
  pIn1->u.i = (int)(pOp - p->aOp) - 1;
  pOp = &aOp[pCaller->p2 - 1];
  break;
}

/* Opcode:  Yield P1 P2 * * *
**
** Swap the program counter with the value in register P1.  This
** has the effect of yielding to a coroutine.
**
** If the coroutine that is launched by this instruction ends with
** Yield or Return then continue to the next instruction.  But if
** the coroutine launched by this instruction ends with
** EndCoroutine, then jump to P2 rather than continuing with the
** next instruction.
**
** See also: InitCoroutine
*/
case OP_Yield: {            /* in1, jump0 */
  int pcDest;
  pIn1 = &aMem[pOp->p1];
  assert( VdbeMemDynamic(pIn1)==0 );
  pIn1->flags = MEM_Int;
  pcDest = (int)pIn1->u.i;
  pIn1->u.i = (int)(pOp - aOp);
  REGISTER_TRACE(pOp->p1, pIn1);
  pOp = &aOp[pcDest];
  break;
}

/* Opcode:  HaltIfNull  P1 P2 P3 P4 P5
** Synopsis: if r[P3]=null halt
**
** Check the value in register P3.  If it is NULL then Halt using
** parameter P1, P2, and P4 as if this were a Halt instruction.  If the
** value in register P3 is not NULL, then this routine is a no-op.
** The P5 parameter should be 1.
*/
case OP_HaltIfNull: {      /* in3 */
  pIn3 = &aMem[pOp->p3];
#ifdef SQLITE_DEBUG
  if( pOp->p2==OE_Abort ){ sqlite3VdbeAssertAbortable(p); }
#endif
  if( (pIn3->flags & MEM_Null)==0 ) break;
  /* Fall through into OP_Halt */
  /* no break */ deliberate_fall_through
}

/* Opcode:  Halt P1 P2 P3 P4 P5
**
** Exit immediately.  All open cursors, etc are closed
** automatically.
**
** P1 is the result code returned by sqlite3_exec(), sqlite3_reset(),
** or sqlite3_finalize().  For a normal halt, this should be SQLITE_OK (0).
** For errors, it can be some other value.  If P1!=0 then P2 will determine
** whether or not to rollback the current transaction.  Do not rollback
** if P2==OE_Fail. Do the rollback if P2==OE_Rollback.  If P2==OE_Abort,
** then back out all changes that have occurred during this execution of the
** VDBE, but do not rollback the transaction.
**
** If P3 is not zero and P4 is NULL, then P3 is a register that holds the
** text of an error message.
**
** If P3 is zero and P4 is not null then the error message string is held
** in P4.
**
** P5 is a value between 1 and 4, inclusive, then the P4 error message
** string is modified as follows:
**
**    1:  NOT NULL constraint failed: P4
**    2:  UNIQUE constraint failed: P4
**    3:  CHECK constraint failed: P4
**    4:  FOREIGN KEY constraint failed: P4
**
** If P3 is zero and P5 is not zero and P4 is NULL, then everything after
** the ":" is omitted.
**
** There is an implied "Halt 0 0 0" instruction inserted at the very end of
** every program.  So a jump past the last instruction of the program
** is the same as executing Halt.
*/
case OP_Halt: {
  VdbeFrame *pFrame;
  int pcx;

#ifdef SQLITE_DEBUG
  if( pOp->p2==OE_Abort ){ sqlite3VdbeAssertAbortable(p); }
#endif
  assert( pOp->p4type==P4_NOTUSED
       || pOp->p4type==P4_STATIC
       || pOp->p4type==P4_DYNAMIC );

  /* A deliberately coded "OP_Halt SQLITE_INTERNAL * * * *" opcode indicates
  ** something is wrong with the code generator.  Raise an assertion in order
  ** to bring this to the attention of fuzzers and other testing tools. */
  assert( pOp->p1!=SQLITE_INTERNAL );

  if( p->pFrame && pOp->p1==SQLITE_OK ){
    /* Halt the sub-program. Return control to the parent frame. */
    pFrame = p->pFrame;
    p->pFrame = pFrame->pParent;
    p->nFrame--;
    sqlite3VdbeSetChanges(db, p->nChange);
    pcx = sqlite3VdbeFrameRestore(pFrame);
    if( pOp->p2==OE_Ignore ){
      /* Instruction pcx is the OP_Program that invoked the sub-program
      ** currently being halted. If the p2 instruction of this OP_Halt
      ** instruction is set to OE_Ignore, then the sub-program is throwing
      ** an IGNORE exception. In this case jump to the address specified
      ** as the p2 of the calling OP_Program.  */

sqlite3.c  view on Meta::CPAN

    p->pFrame->aOnce[iAddr/8] |= 1<<(iAddr & 7);
  }else{
    if( p->aOp[0].p1==pOp->p1 ){
      VdbeBranchTaken(1, 2);
      goto jump_to_p2;
    }
  }
  VdbeBranchTaken(0, 2);
  pOp->p1 = p->aOp[0].p1;
  break;
}

/* Opcode: If P1 P2 P3 * *
**
** Jump to P2 if the value in register P1 is true.  The value
** is considered true if it is numeric and non-zero.  If the value
** in P1 is NULL then take the jump if and only if P3 is non-zero.
*/
case OP_If:  {               /* jump, in1 */
  int c;
  c = sqlite3VdbeBooleanValue(&aMem[pOp->p1], pOp->p3);
  VdbeBranchTaken(c!=0, 2);
  if( c ) goto jump_to_p2;
  break;
}

/* Opcode: IfNot P1 P2 P3 * *
**
** Jump to P2 if the value in register P1 is False.  The value
** is considered false if it has a numeric value of zero.  If the value
** in P1 is NULL then take the jump if and only if P3 is non-zero.
*/
case OP_IfNot: {            /* jump, in1 */
  int c;
  c = !sqlite3VdbeBooleanValue(&aMem[pOp->p1], !pOp->p3);
  VdbeBranchTaken(c!=0, 2);
  if( c ) goto jump_to_p2;
  break;
}

/* Opcode: IsNull P1 P2 * * *
** Synopsis: if r[P1]==NULL goto P2
**
** Jump to P2 if the value in register P1 is NULL.
*/
case OP_IsNull: {            /* same as TK_ISNULL, jump, in1 */
  pIn1 = &aMem[pOp->p1];
  VdbeBranchTaken( (pIn1->flags & MEM_Null)!=0, 2);
  if( (pIn1->flags & MEM_Null)!=0 ){
    goto jump_to_p2;
  }
  break;
}

/* Opcode: IsType P1 P2 P3 P4 P5
** Synopsis: if typeof(P1.P3) in P5 goto P2
**
** Jump to P2 if the type of a column in a btree is one of the types specified
** by the P5 bitmask.
**
** P1 is normally a cursor on a btree for which the row decode cache is
** valid through at least column P3.  In other words, there should have been
** a prior OP_Column for column P3 or greater.  If the cursor is not valid,
** then this opcode might give spurious results.
** The the btree row has fewer than P3 columns, then use P4 as the
** datatype.
**
** If P1 is -1, then P3 is a register number and the datatype is taken
** from the value in that register.
**
** P5 is a bitmask of data types.  SQLITE_INTEGER is the least significant
** (0x01) bit. SQLITE_FLOAT is the 0x02 bit. SQLITE_TEXT is 0x04.
** SQLITE_BLOB is 0x08.  SQLITE_NULL is 0x10.
**
** WARNING: This opcode does not reliably distinguish between NULL and REAL
** when P1>=0.  If the database contains a NaN value, this opcode will think
** that the datatype is REAL when it should be NULL.  When P1<0 and the value
** is already stored in register P3, then this opcode does reliably
** distinguish between NULL and REAL.  The problem only arises then P1>=0.
**
** Take the jump to address P2 if and only if the datatype of the
** value determined by P1 and P3 corresponds to one of the bits in the
** P5 bitmask.
**
*/
case OP_IsType: {        /* jump */
  VdbeCursor *pC;
  u16 typeMask;
  u32 serialType;

  assert( pOp->p1>=(-1) && pOp->p1<p->nCursor );
  assert( pOp->p1>=0 || (pOp->p3>=0 && pOp->p3<=(p->nMem+1 - p->nCursor)) );
  if( pOp->p1>=0 ){
    pC = p->apCsr[pOp->p1];
    assert( pC!=0 );
    assert( pOp->p3>=0 );
    if( pOp->p3<pC->nHdrParsed ){
      serialType = pC->aType[pOp->p3];
      if( serialType>=12 ){
        if( serialType&1 ){
          typeMask = 0x04;   /* SQLITE_TEXT */
        }else{
          typeMask = 0x08;   /* SQLITE_BLOB */
        }
      }else{
        static const unsigned char aMask[] = {
           0x10, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x2,
           0x01, 0x01, 0x10, 0x10
        };
        testcase( serialType==0 );
        testcase( serialType==1 );
        testcase( serialType==2 );
        testcase( serialType==3 );
        testcase( serialType==4 );
        testcase( serialType==5 );
        testcase( serialType==6 );
        testcase( serialType==7 );
        testcase( serialType==8 );
        testcase( serialType==9 );
        testcase( serialType==10 );
        testcase( serialType==11 );
        typeMask = aMask[serialType];
      }
    }else{
      typeMask = 1 << (pOp->p4.i - 1);
      testcase( typeMask==0x01 );
      testcase( typeMask==0x02 );
      testcase( typeMask==0x04 );
      testcase( typeMask==0x08 );
      testcase( typeMask==0x10 );
    }
  }else{
    assert( memIsValid(&aMem[pOp->p3]) );
    typeMask = 1 << (sqlite3_value_type((sqlite3_value*)&aMem[pOp->p3])-1);
    testcase( typeMask==0x01 );
    testcase( typeMask==0x02 );
    testcase( typeMask==0x04 );
    testcase( typeMask==0x08 );
    testcase( typeMask==0x10 );
  }
  VdbeBranchTaken( (typeMask & pOp->p5)!=0, 2);
  if( typeMask & pOp->p5 ){
    goto jump_to_p2;
  }
  break;
}

/* Opcode: ZeroOrNull P1 P2 P3 * *
** Synopsis: r[P2] = 0 OR NULL
**
** If both registers P1 and P3 are NOT NULL, then store a zero in
** register P2.  If either registers P1 or P3 are NULL then put
** a NULL in register P2.
*/
case OP_ZeroOrNull: {            /* in1, in2, out2, in3 */
  if( (aMem[pOp->p1].flags & MEM_Null)!=0
   || (aMem[pOp->p3].flags & MEM_Null)!=0
  ){
    sqlite3VdbeMemSetNull(aMem + pOp->p2);
  }else{
    sqlite3VdbeMemSetInt64(aMem + pOp->p2, 0);
  }
  break;
}

/* Opcode: NotNull P1 P2 * * *
** Synopsis: if r[P1]!=NULL goto P2
**
** Jump to P2 if the value in register P1 is not NULL.
*/
case OP_NotNull: {            /* same as TK_NOTNULL, jump, in1 */
  pIn1 = &aMem[pOp->p1];
  VdbeBranchTaken( (pIn1->flags & MEM_Null)==0, 2);
  if( (pIn1->flags & MEM_Null)==0 ){
    goto jump_to_p2;
  }
  break;
}

/* Opcode: IfNullRow P1 P2 P3 * *
** Synopsis: if P1.nullRow then r[P3]=NULL, goto P2
**
** Check the cursor P1 to see if it is currently pointing at a NULL row.
** If it is, then set register P3 to NULL and jump immediately to P2.
** If P1 is not on a NULL row, then fall through without making any
** changes.
**
** If P1 is not an open cursor, then this opcode is a no-op.
*/
case OP_IfNullRow: {         /* jump */
  VdbeCursor *pC;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  if( pC && pC->nullRow ){
    sqlite3VdbeMemSetNull(aMem + pOp->p3);
    goto jump_to_p2;
  }
  break;
}

#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
/* Opcode: Offset P1 P2 P3 * *
** Synopsis: r[P3] = sqlite_offset(P1)
**
** Store in register r[P3] the byte offset into the database file that is the
** start of the payload for the record at which that cursor P1 is currently
** pointing.
**
** P2 is the column number for the argument to the sqlite_offset() function.
** This opcode does not use P2 itself, but the P2 value is used by the
** code generator.  The P1, P2, and P3 operands to this opcode are the
** same as for OP_Column.
**
** This opcode is only available if SQLite is compiled with the
** -DSQLITE_ENABLE_OFFSET_SQL_FUNC option.
*/
case OP_Offset: {          /* out3 */
  VdbeCursor *pC;    /* The VDBE cursor */
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  pOut = &p->aMem[pOp->p3];
  if( pC==0 || pC->eCurType!=CURTYPE_BTREE ){
    sqlite3VdbeMemSetNull(pOut);
  }else{
    if( pC->deferredMoveto ){
      rc = sqlite3VdbeFinishMoveto(pC);
      if( rc ) goto abort_due_to_error;
    }
    if( sqlite3BtreeEof(pC->uc.pCursor) ){
      sqlite3VdbeMemSetNull(pOut);
    }else{
      sqlite3VdbeMemSetInt64(pOut, sqlite3BtreeOffset(pC->uc.pCursor));
    }
  }
  break;
}
#endif /* SQLITE_ENABLE_OFFSET_SQL_FUNC */

/* Opcode: Column P1 P2 P3 P4 P5
** Synopsis: r[P3]=PX cursor P1 column P2
**
** Interpret the data that cursor P1 points to as a structure built using
** the MakeRecord instruction.  (See the MakeRecord opcode for additional
** information about the format of the data.)  Extract the P2-th column
** from this record.  If there are less than (P2+1)
** values in the record, extract a NULL.
**
** The value extracted is stored in register P3.
**
** If the record contains fewer than P2 fields, then extract a NULL.  Or,
** if the P4 argument is a P4_MEM use the value of the P4 argument as
** the result.
**
** If the OPFLAG_LENGTHARG bit is set in P5 then the result is guaranteed
** to only be used by the length() function or the equivalent.  The content
** of large blobs is not loaded, thus saving CPU cycles.  If the
** OPFLAG_TYPEOFARG bit is set then the result will only be used by the
** typeof() function or the IS NULL or IS NOT NULL operators or the
** equivalent.  In this case, all content loading can be omitted.
*/
case OP_Column: {            /* ncycle */
  u32 p2;            /* column number to retrieve */
  VdbeCursor *pC;    /* The VDBE cursor */
  BtCursor *pCrsr;   /* The B-Tree cursor corresponding to pC */
  u32 *aOffset;      /* aOffset[i] is offset to start of data for i-th column */
  int len;           /* The length of the serialized data for the column */
  int i;             /* Loop counter */
  Mem *pDest;        /* Where to write the extracted value */
  Mem sMem;          /* For storing the record being decoded */
  const u8 *zData;   /* Part of the record being decoded */
  const u8 *zHdr;    /* Next unparsed byte of the header */
  const u8 *zEndHdr; /* Pointer to first byte after the header */
  u64 offset64;      /* 64-bit offset */
  u32 t;             /* A type code from the record header */
  Mem *pReg;         /* PseudoTable input register */

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
  pC = p->apCsr[pOp->p1];
  p2 = (u32)pOp->p2;

op_column_restart:
  assert( pC!=0 );
  assert( p2<(u32)pC->nField
       || (pC->eCurType==CURTYPE_PSEUDO && pC->seekResult==0) );
  aOffset = pC->aOffset;
  assert( aOffset==pC->aType+pC->nField );
  assert( pC->eCurType!=CURTYPE_VTAB );
  assert( pC->eCurType!=CURTYPE_PSEUDO || pC->nullRow );
  assert( pC->eCurType!=CURTYPE_SORTER );

  if( pC->cacheStatus!=p->cacheCtr ){                /*OPTIMIZATION-IF-FALSE*/
    if( pC->nullRow ){
      if( pC->eCurType==CURTYPE_PSEUDO && pC->seekResult>0 ){
        /* For the special case of as pseudo-cursor, the seekResult field
        ** identifies the register that holds the record */
        pReg = &aMem[pC->seekResult];
        assert( pReg->flags & MEM_Blob );
        assert( memIsValid(pReg) );
        pC->payloadSize = pC->szRow = pReg->n;
        pC->aRow = (u8*)pReg->z;
      }else{
        pDest = &aMem[pOp->p3];
        memAboutToChange(p, pDest);
        sqlite3VdbeMemSetNull(pDest);
        goto op_column_out;
      }
    }else{
      pCrsr = pC->uc.pCursor;
      if( pC->deferredMoveto ){
        u32 iMap;
        assert( !pC->isEphemeral );
        if( pC->ub.aAltMap && (iMap = pC->ub.aAltMap[1+p2])>0  ){
          pC = pC->pAltCursor;
          p2 = iMap - 1;
          goto op_column_restart;
        }
        rc = sqlite3VdbeFinishMoveto(pC);
        if( rc ) goto abort_due_to_error;
      }else if( sqlite3BtreeCursorHasMoved(pCrsr) ){
        rc = sqlite3VdbeHandleMovedCursor(pC);
        if( rc ) goto abort_due_to_error;
        goto op_column_restart;
      }
      assert( pC->eCurType==CURTYPE_BTREE );
      assert( pCrsr );
      assert( sqlite3BtreeCursorIsValid(pCrsr) );
      pC->payloadSize = sqlite3BtreePayloadSize(pCrsr);
      pC->aRow = sqlite3BtreePayloadFetch(pCrsr, &pC->szRow);
      assert( pC->szRow<=pC->payloadSize );
      assert( pC->szRow<=65536 );  /* Maximum page size is 64KiB */
    }
    pC->cacheStatus = p->cacheCtr;
    if( (aOffset[0] = pC->aRow[0])<0x80 ){
      pC->iHdrOffset = 1;
    }else{
      pC->iHdrOffset = sqlite3GetVarint32(pC->aRow, aOffset);
    }
    pC->nHdrParsed = 0;

    if( pC->szRow<aOffset[0] ){      /*OPTIMIZATION-IF-FALSE*/
      /* pC->aRow does not have to hold the entire row, but it does at least
      ** need to cover the header of the record.  If pC->aRow does not contain
      ** the complete header, then set it to zero, forcing the header to be
      ** dynamically allocated. */
      pC->aRow = 0;
      pC->szRow = 0;

      /* Make sure a corrupt database has not given us an oversize header.
      ** Do this now to avoid an oversize memory allocation.
      **
      ** Type entries can be between 1 and 5 bytes each.  But 4 and 5 byte
      ** types use so much data space that there can only be 4096 and 32 of
      ** them, respectively.  So the maximum header length results from a
      ** 3-byte type for each of the maximum of 32768 columns plus three

sqlite3.c  view on Meta::CPAN

        /* NULL value.  No change in zPayload */
      }else{
        u64 v;
        if( serial_type==7 ){
          assert( sizeof(v)==sizeof(pRec->u.r) );
          memcpy(&v, &pRec->u.r, sizeof(v));
          swapMixedEndianFloat(v);
        }else{
          v = pRec->u.i;
        }
        len = sqlite3SmallTypeSizes[serial_type];
        assert( len>=1 && len<=8 && len!=5 && len!=7 );
        switch( len ){
          default: zPayload[7] = (u8)(v&0xff); v >>= 8;
                   zPayload[6] = (u8)(v&0xff); v >>= 8;
                   /* no break */ deliberate_fall_through
          case 6:  zPayload[5] = (u8)(v&0xff); v >>= 8;
                   zPayload[4] = (u8)(v&0xff); v >>= 8;
                   /* no break */ deliberate_fall_through
          case 4:  zPayload[3] = (u8)(v&0xff); v >>= 8;
                   /* no break */ deliberate_fall_through
          case 3:  zPayload[2] = (u8)(v&0xff); v >>= 8;
                   /* no break */ deliberate_fall_through
          case 2:  zPayload[1] = (u8)(v&0xff); v >>= 8;
                   /* no break */ deliberate_fall_through
          case 1:  zPayload[0] = (u8)(v&0xff);
        }
        zPayload += len;
      }
    }else if( serial_type<0x80 ){
      *(zHdr++) = serial_type;
      if( serial_type>=14 && pRec->n>0 ){
        assert( pRec->z!=0 );
        memcpy(zPayload, pRec->z, pRec->n);
        zPayload += pRec->n;
      }
    }else{
      zHdr += sqlite3PutVarint(zHdr, serial_type);
      if( pRec->n ){
        assert( pRec->z!=0 );
        assert( pRec->z!=(const char*)sqlite3CtypeMap );
        memcpy(zPayload, pRec->z, pRec->n);
        zPayload += pRec->n;
      }
    }
    if( pRec==pLast ) break;
    pRec++;
  }
  assert( nHdr==(int)(zHdr - (u8*)pOut->z) );
  assert( nByte==(int)(zPayload - (u8*)pOut->z) );

  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
  REGISTER_TRACE(pOp->p3, pOut);
  break;
}

/* Opcode: Count P1 P2 P3 * *
** Synopsis: r[P2]=count()
**
** Store the number of entries (an integer value) in the table or index
** opened by cursor P1 in register P2.
**
** If P3==0, then an exact count is obtained, which involves visiting
** every btree page of the table.  But if P3 is non-zero, an estimate
** is returned based on the current cursor position.
*/
case OP_Count: {         /* out2 */
  i64 nEntry;
  BtCursor *pCrsr;

  assert( p->apCsr[pOp->p1]->eCurType==CURTYPE_BTREE );
  pCrsr = p->apCsr[pOp->p1]->uc.pCursor;
  assert( pCrsr );
  if( pOp->p3 ){
    nEntry = sqlite3BtreeRowCountEst(pCrsr);
  }else{
    nEntry = 0;  /* Not needed.  Only used to silence a warning. */
    rc = sqlite3BtreeCount(db, pCrsr, &nEntry);
    if( rc ) goto abort_due_to_error;
  }
  pOut = out2Prerelease(p, pOp);
  pOut->u.i = nEntry;
  goto check_for_interrupt;
}

/* Opcode: Savepoint P1 * * P4 *
**
** Open, release or rollback the savepoint named by parameter P4, depending
** on the value of P1. To open a new savepoint set P1==0 (SAVEPOINT_BEGIN).
** To release (commit) an existing savepoint set P1==1 (SAVEPOINT_RELEASE).
** To rollback an existing savepoint set P1==2 (SAVEPOINT_ROLLBACK).
*/
case OP_Savepoint: {
  int p1;                         /* Value of P1 operand */
  char *zName;                    /* Name of savepoint */
  int nName;
  Savepoint *pNew;
  Savepoint *pSavepoint;
  Savepoint *pTmp;
  int iSavepoint;
  int ii;

  p1 = pOp->p1;
  zName = pOp->p4.z;

  /* Assert that the p1 parameter is valid. Also that if there is no open
  ** transaction, then there cannot be any savepoints.
  */
  assert( db->pSavepoint==0 || db->autoCommit==0 );
  assert( p1==SAVEPOINT_BEGIN||p1==SAVEPOINT_RELEASE||p1==SAVEPOINT_ROLLBACK );
  assert( db->pSavepoint || db->isTransactionSavepoint==0 );
  assert( checkSavepointCount(db) );
  assert( p->bIsReader );

  if( p1==SAVEPOINT_BEGIN ){
    if( db->nVdbeWrite>0 ){
      /* A new savepoint cannot be created if there are active write
      ** statements (i.e. open read/write incremental blob handles).
      */
      sqlite3VdbeError(p, "cannot open savepoint - SQL statements in progress");
      rc = SQLITE_BUSY;
    }else{
      nName = sqlite3Strlen30(zName);

#ifndef SQLITE_OMIT_VIRTUALTABLE

sqlite3.c  view on Meta::CPAN

      if( rc==SQLITE_OK ){
        rc = sqlite3BtreeBeginStmt(pBt, p->iStatement);
      }

      /* Store the current value of the database handles deferred constraint
      ** counter. If the statement transaction needs to be rolled back,
      ** the value of this counter needs to be restored too.  */
      p->nStmtDefCons = db->nDeferredCons;
      p->nStmtDefImmCons = db->nDeferredImmCons;
    }
  }
  assert( pOp->p5==0 || pOp->p4type==P4_INT32 );
  if( rc==SQLITE_OK
   && pOp->p5
   && (iMeta!=pOp->p3 || pDb->pSchema->iGeneration!=pOp->p4.i)
  ){
    /*
    ** IMPLEMENTATION-OF: R-03189-51135 As each SQL statement runs, the schema
    ** version is checked to ensure that the schema has not changed since the
    ** SQL statement was prepared.
    */
    sqlite3DbFree(db, p->zErrMsg);
    p->zErrMsg = sqlite3DbStrDup(db, "database schema has changed");
    /* If the schema-cookie from the database file matches the cookie
    ** stored with the in-memory representation of the schema, do
    ** not reload the schema from the database file.
    **
    ** If virtual-tables are in use, this is not just an optimization.
    ** Often, v-tables store their data in other SQLite tables, which
    ** are queried from within xNext() and other v-table methods using
    ** prepared queries. If such a query is out-of-date, we do not want to
    ** discard the database schema, as the user code implementing the
    ** v-table would have to be ready for the sqlite3_vtab structure itself
    ** to be invalidated whenever sqlite3_step() is called from within
    ** a v-table method.
    */
    if( db->aDb[pOp->p1].pSchema->schema_cookie!=iMeta ){
      sqlite3ResetOneSchema(db, pOp->p1);
    }
    p->expired = 1;
    rc = SQLITE_SCHEMA;

    /* Set changeCntOn to 0 to prevent the value returned by sqlite3_changes()
    ** from being modified in sqlite3VdbeHalt(). If this statement is
    ** reprepared, changeCntOn will be set again. */
    p->changeCntOn = 0;
  }
  if( rc ) goto abort_due_to_error;
  break;
}

/* Opcode: ReadCookie P1 P2 P3 * *
**
** Read cookie number P3 from database P1 and write it into register P2.
** P3==1 is the schema version.  P3==2 is the database format.
** P3==3 is the recommended pager cache size, and so forth.  P1==0 is
** the main database file and P1==1 is the database file used to store
** temporary tables.
**
** There must be a read-lock on the database (either a transaction
** must be started or there must be an open cursor) before
** executing this instruction.
*/
case OP_ReadCookie: {               /* out2 */
  int iMeta;
  int iDb;
  int iCookie;

  assert( p->bIsReader );
  iDb = pOp->p1;
  iCookie = pOp->p3;
  assert( pOp->p3<SQLITE_N_BTREE_META );
  assert( iDb>=0 && iDb<db->nDb );
  assert( db->aDb[iDb].pBt!=0 );
  assert( DbMaskTest(p->btreeMask, iDb) );

  sqlite3BtreeGetMeta(db->aDb[iDb].pBt, iCookie, (u32 *)&iMeta);
  pOut = out2Prerelease(p, pOp);
  pOut->u.i = iMeta;
  break;
}

/* Opcode: SetCookie P1 P2 P3 * P5
**
** Write the integer value P3 into cookie number P2 of database P1.
** P2==1 is the schema version.  P2==2 is the database format.
** P2==3 is the recommended pager cache
** size, and so forth.  P1==0 is the main database file and P1==1 is the
** database file used to store temporary tables.
**
** A transaction must be started before executing this opcode.
**
** If P2 is the SCHEMA_VERSION cookie (cookie number 1) then the internal
** schema version is set to P3-P5.  The "PRAGMA schema_version=N" statement
** has P5 set to 1, so that the internal schema version will be different
** from the database schema version, resulting in a schema reset.
*/
case OP_SetCookie: {
  Db *pDb;

  sqlite3VdbeIncrWriteCounter(p, 0);
  assert( pOp->p2<SQLITE_N_BTREE_META );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( DbMaskTest(p->btreeMask, pOp->p1) );
  assert( p->readOnly==0 );
  pDb = &db->aDb[pOp->p1];
  assert( pDb->pBt!=0 );
  assert( sqlite3SchemaMutexHeld(db, pOp->p1, 0) );
  /* See note about index shifting on OP_ReadCookie */
  rc = sqlite3BtreeUpdateMeta(pDb->pBt, pOp->p2, pOp->p3);
  if( pOp->p2==BTREE_SCHEMA_VERSION ){
    /* When the schema cookie changes, record the new cookie internally */
    *(u32*)&pDb->pSchema->schema_cookie = *(u32*)&pOp->p3 - pOp->p5;
    db->mDbFlags |= DBFLAG_SchemaChange;
    sqlite3FkClearTriggerCache(db, pOp->p1);
  }else if( pOp->p2==BTREE_FILE_FORMAT ){
    /* Record changes in the file format */
    pDb->pSchema->file_format = pOp->p3;
  }
  if( pOp->p1==1 ){
    /* Invalidate all prepared statements whenever the TEMP database
    ** schema is changed.  Ticket #1644 */
    sqlite3ExpirePreparedStatements(db, 0);
    p->expired = 0;
  }
  if( rc ) goto abort_due_to_error;
  break;
}

/* Opcode: OpenRead P1 P2 P3 P4 P5
** Synopsis: root=P2 iDb=P3
**
** Open a read-only cursor for the database table whose root page is
** P2 in a database file.  The database file is determined by P3.
** P3==0 means the main database, P3==1 means the database used for
** temporary tables, and P3>1 means used the corresponding attached
** database.  Give the new cursor an identifier of P1.  The P1
** values need not be contiguous but all P1 values should be small integers.
** It is an error for P1 to be negative.
**
** Allowed P5 bits:
** <ul>
** <li>  <b>0x02 OPFLAG_SEEKEQ</b>: This cursor will only be used for
**       equality lookups (implemented as a pair of opcodes OP_SeekGE/OP_IdxGT
**       of OP_SeekLE/OP_IdxLT)
** </ul>
**
** The P4 value may be either an integer (P4_INT32) or a pointer to
** a KeyInfo structure (P4_KEYINFO). If it is a pointer to a KeyInfo
** object, then table being opened must be an [index b-tree] where the
** KeyInfo object defines the content and collating
** sequence of that index b-tree. Otherwise, if P4 is an integer
** value, then the table being opened must be a [table b-tree] with a
** number of columns no less than the value of P4.
**
** See also: OpenWrite, ReopenIdx
*/
/* Opcode: ReopenIdx P1 P2 P3 P4 P5
** Synopsis: root=P2 iDb=P3
**
** The ReopenIdx opcode works like OP_OpenRead except that it first
** checks to see if the cursor on P1 is already open on the same
** b-tree and if it is this opcode becomes a no-op.  In other words,
** if the cursor is already open, do not reopen it.
**
** The ReopenIdx opcode may only be used with P5==0 or P5==OPFLAG_SEEKEQ
** and with P4 being a P4_KEYINFO object.  Furthermore, the P3 value must
** be the same as every other ReopenIdx or OpenRead for the same cursor
** number.
**
** Allowed P5 bits:
** <ul>
** <li>  <b>0x02 OPFLAG_SEEKEQ</b>: This cursor will only be used for
**       equality lookups (implemented as a pair of opcodes OP_SeekGE/OP_IdxGT
**       of OP_SeekLE/OP_IdxLT)
** </ul>
**
** See also: OP_OpenRead, OP_OpenWrite
*/
/* Opcode: OpenWrite P1 P2 P3 P4 P5
** Synopsis: root=P2 iDb=P3
**
** Open a read/write cursor named P1 on the table or index whose root
** page is P2 (or whose root page is held in register P2 if the
** OPFLAG_P2ISREG bit is set in P5 - see below).
**
** The P4 value may be either an integer (P4_INT32) or a pointer to
** a KeyInfo structure (P4_KEYINFO). If it is a pointer to a KeyInfo
** object, then table being opened must be an [index b-tree] where the
** KeyInfo object defines the content and collating
** sequence of that index b-tree. Otherwise, if P4 is an integer
** value, then the table being opened must be a [table b-tree] with a
** number of columns no less than the value of P4.
**
** Allowed P5 bits:
** <ul>
** <li>  <b>0x02 OPFLAG_SEEKEQ</b>: This cursor will only be used for
**       equality lookups (implemented as a pair of opcodes OP_SeekGE/OP_IdxGT
**       of OP_SeekLE/OP_IdxLT)
** <li>  <b>0x08 OPFLAG_FORDELETE</b>: This cursor is used only to seek
**       and subsequently delete entries in an index btree.  This is a
**       hint to the storage engine that the storage engine is allowed to
**       ignore.  The hint is not used by the official SQLite b*tree storage
**       engine, but is used by COMDB2.
** <li>  <b>0x10 OPFLAG_P2ISREG</b>: Use the content of register P2
**       as the root page, not the value of P2 itself.
** </ul>
**
** This instruction works like OpenRead except that it opens the cursor
** in read/write mode.
**
** See also: OP_OpenRead, OP_ReopenIdx
*/
case OP_ReopenIdx: {         /* ncycle */
  int nField;
  KeyInfo *pKeyInfo;
  u32 p2;
  int iDb;
  int wrFlag;
  Btree *pX;
  VdbeCursor *pCur;
  Db *pDb;

  assert( pOp->p5==0 || pOp->p5==OPFLAG_SEEKEQ );
  assert( pOp->p4type==P4_KEYINFO );
  pCur = p->apCsr[pOp->p1];
  if( pCur && pCur->pgnoRoot==(u32)pOp->p2 ){
    assert( pCur->iDb==pOp->p3 );      /* Guaranteed by the code generator */
    assert( pCur->eCurType==CURTYPE_BTREE );
    sqlite3BtreeClearCursor(pCur->uc.pCursor);
    goto open_cursor_set_hints;
  }
  /* If the cursor is not currently open or is open on a different
  ** index, then fall through into OP_OpenRead to force a reopen */
case OP_OpenRead:            /* ncycle */
case OP_OpenWrite:

  assert( pOp->opcode==OP_OpenWrite || pOp->p5==0 || pOp->p5==OPFLAG_SEEKEQ );
  assert( p->bIsReader );
  assert( pOp->opcode==OP_OpenRead || pOp->opcode==OP_ReopenIdx
          || p->readOnly==0 );

  if( p->expired==1 ){
    rc = SQLITE_ABORT_ROLLBACK;
    goto abort_due_to_error;
  }

  nField = 0;
  pKeyInfo = 0;
  p2 = (u32)pOp->p2;
  iDb = pOp->p3;
  assert( iDb>=0 && iDb<db->nDb );
  assert( DbMaskTest(p->btreeMask, iDb) );
  pDb = &db->aDb[iDb];
  pX = pDb->pBt;
  assert( pX!=0 );
  if( pOp->opcode==OP_OpenWrite ){
    assert( OPFLAG_FORDELETE==BTREE_FORDELETE );
    wrFlag = BTREE_WRCSR | (pOp->p5 & OPFLAG_FORDELETE);
    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
    if( pDb->pSchema->file_format < p->minWriteFileFormat ){
      p->minWriteFileFormat = pDb->pSchema->file_format;
    }
    if( pOp->p5 & OPFLAG_P2ISREG ){
      assert( p2>0 );
      assert( p2<=(u32)(p->nMem+1 - p->nCursor) );
      pIn2 = &aMem[p2];
      assert( memIsValid(pIn2) );
      assert( (pIn2->flags & MEM_Int)!=0 );
      sqlite3VdbeMemIntegerify(pIn2);
      p2 = (int)pIn2->u.i;
      /* The p2 value always comes from a prior OP_CreateBtree opcode and
      ** that opcode will always set the p2 value to 2 or more or else fail.
      ** If there were a failure, the prepared statement would have halted
      ** before reaching this instruction. */
      assert( p2>=2 );
    }
  }else{
    wrFlag = 0;
    assert( (pOp->p5 & OPFLAG_P2ISREG)==0 );
  }
  if( pOp->p4type==P4_KEYINFO ){
    pKeyInfo = pOp->p4.pKeyInfo;
    assert( pKeyInfo->enc==ENC(db) );
    assert( pKeyInfo->db==db );
    nField = pKeyInfo->nAllField;
  }else if( pOp->p4type==P4_INT32 ){
    nField = pOp->p4.i;
  }
  assert( pOp->p1>=0 );
  assert( nField>=0 );
  testcase( nField==0 );  /* Table with INTEGER PRIMARY KEY and nothing else */
  pCur = allocateCursor(p, pOp->p1, nField, CURTYPE_BTREE);
  if( pCur==0 ) goto no_mem;
  pCur->iDb = iDb;
  pCur->nullRow = 1;
  pCur->isOrdered = 1;
  pCur->pgnoRoot = p2;
#ifdef SQLITE_DEBUG
  pCur->wrFlag = wrFlag;
#endif
  rc = sqlite3BtreeCursor(pX, p2, wrFlag, pKeyInfo, pCur->uc.pCursor);
  pCur->pKeyInfo = pKeyInfo;
  /* Set the VdbeCursor.isTable variable. Previous versions of
  ** SQLite used to check if the root-page flags were sane at this point
  ** and report database corruption if they were not, but this check has
  ** since moved into the btree layer.  */
  pCur->isTable = pOp->p4type!=P4_KEYINFO;

open_cursor_set_hints:
  assert( OPFLAG_BULKCSR==BTREE_BULKLOAD );
  assert( OPFLAG_SEEKEQ==BTREE_SEEK_EQ );
  testcase( pOp->p5 & OPFLAG_BULKCSR );
  testcase( pOp->p2 & OPFLAG_SEEKEQ );
  sqlite3BtreeCursorHintFlags(pCur->uc.pCursor,
                               (pOp->p5 & (OPFLAG_BULKCSR|OPFLAG_SEEKEQ)));
  if( rc ) goto abort_due_to_error;
  break;
}

/* Opcode: OpenDup P1 P2 * * *
**
** Open a new cursor P1 that points to the same ephemeral table as
** cursor P2.  The P2 cursor must have been opened by a prior OP_OpenEphemeral
** opcode.  Only ephemeral cursors may be duplicated.
**
** Duplicate ephemeral cursors are used for self-joins of materialized views.
*/
case OP_OpenDup: {           /* ncycle */
  VdbeCursor *pOrig;    /* The original cursor to be duplicated */
  VdbeCursor *pCx;      /* The new cursor */

  pOrig = p->apCsr[pOp->p2];
  assert( pOrig );
  assert( pOrig->isEphemeral );  /* Only ephemeral cursors can be duplicated */

  pCx = allocateCursor(p, pOp->p1, pOrig->nField, CURTYPE_BTREE);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->isEphemeral = 1;
  pCx->pKeyInfo = pOrig->pKeyInfo;
  pCx->isTable = pOrig->isTable;
  pCx->pgnoRoot = pOrig->pgnoRoot;
  pCx->isOrdered = pOrig->isOrdered;
  pCx->ub.pBtx = pOrig->ub.pBtx;
  pCx->noReuse = 1;
  pOrig->noReuse = 1;
  rc = sqlite3BtreeCursor(pCx->ub.pBtx, pCx->pgnoRoot, BTREE_WRCSR,
                          pCx->pKeyInfo, pCx->uc.pCursor);
  /* The sqlite3BtreeCursor() routine can only fail for the first cursor
  ** opened for a database.  Since there is already an open cursor when this
  ** opcode is run, the sqlite3BtreeCursor() cannot fail */
  assert( rc==SQLITE_OK );
  break;
}


/* Opcode: OpenEphemeral P1 P2 P3 P4 P5
** Synopsis: nColumn=P2
**
** Open a new cursor P1 to a transient table.
** The cursor is always opened read/write even if
** the main database is read-only.  The ephemeral
** table is deleted automatically when the cursor is closed.
**
** If the cursor P1 is already opened on an ephemeral table, the table
** is cleared (all content is erased).
**
** P2 is the number of columns in the ephemeral table.
** The cursor points to a BTree table if P4==0 and to a BTree index
** if P4 is not 0.  If P4 is not NULL, it points to a KeyInfo structure
** that defines the format of keys in the index.
**
** The P5 parameter can be a mask of the BTREE_* flags defined
** in btree.h.  These flags control aspects of the operation of
** the btree.  The BTREE_OMIT_JOURNAL and BTREE_SINGLE flags are
** added automatically.
**
** If P3 is positive, then reg[P3] is modified slightly so that it
** can be used as zero-length data for OP_Insert.  This is an optimization
** that avoids an extra OP_Blob opcode to initialize that register.
*/
/* Opcode: OpenAutoindex P1 P2 * P4 *
** Synopsis: nColumn=P2
**
** This opcode works the same as OP_OpenEphemeral.  It has a
** different name to distinguish its use.  Tables created using
** by this opcode will be used for automatically created transient
** indices in joins.
*/
case OP_OpenAutoindex:       /* ncycle */
case OP_OpenEphemeral: {     /* ncycle */
  VdbeCursor *pCx;
  KeyInfo *pKeyInfo;

  static const int vfsFlags =
      SQLITE_OPEN_READWRITE |
      SQLITE_OPEN_CREATE |
      SQLITE_OPEN_EXCLUSIVE |
      SQLITE_OPEN_DELETEONCLOSE |
      SQLITE_OPEN_TRANSIENT_DB;
  assert( pOp->p1>=0 );
  assert( pOp->p2>=0 );
  if( pOp->p3>0 ){
    /* Make register reg[P3] into a value that can be used as the data
    ** form sqlite3BtreeInsert() where the length of the data is zero. */
    assert( pOp->p2==0 ); /* Only used when number of columns is zero */
    assert( pOp->opcode==OP_OpenEphemeral );
    assert( aMem[pOp->p3].flags & MEM_Null );
    aMem[pOp->p3].n = 0;
    aMem[pOp->p3].z = "";
  }
  pCx = p->apCsr[pOp->p1];
  if( pCx && !pCx->noReuse &&  ALWAYS(pOp->p2<=pCx->nField) ){
    /* If the ephemeral table is already open and has no duplicates from
    ** OP_OpenDup, then erase all existing content so that the table is
    ** empty again, rather than creating a new table. */
    assert( pCx->isEphemeral );
    pCx->seqCount = 0;
    pCx->cacheStatus = CACHE_STALE;
    rc = sqlite3BtreeClearTable(pCx->ub.pBtx, pCx->pgnoRoot, 0);
  }else{
    pCx = allocateCursor(p, pOp->p1, pOp->p2, CURTYPE_BTREE);
    if( pCx==0 ) goto no_mem;
    pCx->isEphemeral = 1;
    rc = sqlite3BtreeOpen(db->pVfs, 0, db, &pCx->ub.pBtx,
                          BTREE_OMIT_JOURNAL | BTREE_SINGLE | pOp->p5,
                          vfsFlags);
    if( rc==SQLITE_OK ){
      rc = sqlite3BtreeBeginTrans(pCx->ub.pBtx, 1, 0);

sqlite3.c  view on Meta::CPAN

          assert( pOp->p4type==P4_KEYINFO );
          rc = sqlite3BtreeCreateTable(pCx->ub.pBtx, &pCx->pgnoRoot,
              BTREE_BLOBKEY | pOp->p5);
          if( rc==SQLITE_OK ){
            assert( pCx->pgnoRoot==SCHEMA_ROOT+1 );
            assert( pKeyInfo->db==db );
            assert( pKeyInfo->enc==ENC(db) );
            rc = sqlite3BtreeCursor(pCx->ub.pBtx, pCx->pgnoRoot, BTREE_WRCSR,
                pKeyInfo, pCx->uc.pCursor);
          }
          pCx->isTable = 0;
        }else{
          pCx->pgnoRoot = SCHEMA_ROOT;
          rc = sqlite3BtreeCursor(pCx->ub.pBtx, SCHEMA_ROOT, BTREE_WRCSR,
              0, pCx->uc.pCursor);
          pCx->isTable = 1;
        }
      }
      pCx->isOrdered = (pOp->p5!=BTREE_UNORDERED);
      assert( p->apCsr[pOp->p1]==pCx );
      if( rc ){
        assert( !sqlite3BtreeClosesWithCursor(pCx->ub.pBtx, pCx->uc.pCursor) );
        sqlite3BtreeClose(pCx->ub.pBtx);
        p->apCsr[pOp->p1] = 0;  /* Not required; helps with static analysis */
      }else{
        assert( sqlite3BtreeClosesWithCursor(pCx->ub.pBtx, pCx->uc.pCursor) );
      }
    }
  }
  if( rc ) goto abort_due_to_error;
  pCx->nullRow = 1;
  break;
}

/* Opcode: SorterOpen P1 P2 P3 P4 *
**
** This opcode works like OP_OpenEphemeral except that it opens
** a transient index that is specifically designed to sort large
** tables using an external merge-sort algorithm.
**
** If argument P3 is non-zero, then it indicates that the sorter may
** assume that a stable sort considering the first P3 fields of each
** key is sufficient to produce the required results.
*/
case OP_SorterOpen: {
  VdbeCursor *pCx;

  assert( pOp->p1>=0 );
  assert( pOp->p2>=0 );
  pCx = allocateCursor(p, pOp->p1, pOp->p2, CURTYPE_SORTER);
  if( pCx==0 ) goto no_mem;
  pCx->pKeyInfo = pOp->p4.pKeyInfo;
  assert( pCx->pKeyInfo->db==db );
  assert( pCx->pKeyInfo->enc==ENC(db) );
  rc = sqlite3VdbeSorterInit(db, pOp->p3, pCx);
  if( rc ) goto abort_due_to_error;
  break;
}

/* Opcode: SequenceTest P1 P2 * * *
** Synopsis: if( cursor[P1].ctr++ ) pc = P2
**
** P1 is a sorter cursor. If the sequence counter is currently zero, jump
** to P2. Regardless of whether or not the jump is taken, increment the
** the sequence value.
*/
case OP_SequenceTest: {
  VdbeCursor *pC;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( isSorter(pC) );
  if( (pC->seqCount++)==0 ){
    goto jump_to_p2;
  }
  break;
}

/* Opcode: OpenPseudo P1 P2 P3 * *
** Synopsis: P3 columns in r[P2]
**
** Open a new cursor that points to a fake table that contains a single
** row of data.  The content of that one row is the content of memory
** register P2.  In other words, cursor P1 becomes an alias for the
** MEM_Blob content contained in register P2.
**
** A pseudo-table created by this opcode is used to hold a single
** row output from the sorter so that the row can be decomposed into
** individual columns using the OP_Column opcode.  The OP_Column opcode
** is the only cursor opcode that works with a pseudo-table.
**
** P3 is the number of fields in the records that will be stored by
** the pseudo-table.  If P2 is 0 or negative then the pseudo-cursor
** will return NULL for every column.
*/
case OP_OpenPseudo: {
  VdbeCursor *pCx;

  assert( pOp->p1>=0 );
  assert( pOp->p3>=0 );
  pCx = allocateCursor(p, pOp->p1, pOp->p3, CURTYPE_PSEUDO);
  if( pCx==0 ) goto no_mem;
  pCx->nullRow = 1;
  pCx->seekResult = pOp->p2;
  pCx->isTable = 1;
  /* Give this pseudo-cursor a fake BtCursor pointer so that pCx
  ** can be safely passed to sqlite3VdbeCursorMoveto().  This avoids a test
  ** for pCx->eCurType==CURTYPE_BTREE inside of sqlite3VdbeCursorMoveto()
  ** which is a performance optimization */
  pCx->uc.pCursor = sqlite3BtreeFakeValidCursor();
  assert( pOp->p5==0 );
  break;
}

/* Opcode: Close P1 * * * *
**
** Close a cursor previously opened as P1.  If P1 is not
** currently open, this instruction is a no-op.
*/
case OP_Close: {             /* ncycle */
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  sqlite3VdbeFreeCursor(p, p->apCsr[pOp->p1]);
  p->apCsr[pOp->p1] = 0;
  break;
}

#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
/* Opcode: ColumnsUsed P1 * * P4 *
**
** This opcode (which only exists if SQLite was compiled with
** SQLITE_ENABLE_COLUMN_USED_MASK) identifies which columns of the
** table or index for cursor P1 are used.  P4 is a 64-bit integer
** (P4_INT64) in which the first 63 bits are one for each of the
** first 63 columns of the table or index that are actually used
** by the cursor.  The high-order bit is set if any column after
** the 64th is used.
*/
case OP_ColumnsUsed: {
  VdbeCursor *pC;
  pC = p->apCsr[pOp->p1];
  assert( pC->eCurType==CURTYPE_BTREE );
  pC->maskUsed = *(u64*)pOp->p4.pI64;
  break;
}
#endif

/* Opcode: SeekGE P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
** use the value in register P3 as the key.  If cursor P1 refers
** to an SQL index, then P3 is the first in an array of P4 registers
** that are used as an unpacked index key.
**
** Reposition cursor P1 so that  it points to the smallest entry that
** is greater than or equal to the key value. If there are no records
** greater than or equal to the key and P2 is not zero, then jump to P2.
**
** If the cursor P1 was opened using the OPFLAG_SEEKEQ flag, then this
** opcode will either land on a record that exactly matches the key, or
** else it will cause a jump to P2.  When the cursor is OPFLAG_SEEKEQ,
** this opcode must be followed by an IdxLE opcode with the same arguments.
** The IdxGT opcode will be skipped if this opcode succeeds, but the
** IdxGT opcode will be used on subsequent loop iterations.  The
** OPFLAG_SEEKEQ flags is a hint to the btree layer to say that this
** is an equality search.
**
** This opcode leaves the cursor configured to move in forward order,
** from the beginning toward the end.  In other words, the cursor is
** configured to use Next, not Prev.
**
** See also: Found, NotFound, SeekLt, SeekGt, SeekLe
*/
/* Opcode: SeekGT P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
** use the value in register P3 as a key. If cursor P1 refers
** to an SQL index, then P3 is the first in an array of P4 registers
** that are used as an unpacked index key.
**
** Reposition cursor P1 so that it points to the smallest entry that
** is greater than the key value. If there are no records greater than
** the key and P2 is not zero, then jump to P2.
**
** This opcode leaves the cursor configured to move in forward order,
** from the beginning toward the end.  In other words, the cursor is
** configured to use Next, not Prev.
**
** See also: Found, NotFound, SeekLt, SeekGe, SeekLe
*/
/* Opcode: SeekLT P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
** use the value in register P3 as a key. If cursor P1 refers
** to an SQL index, then P3 is the first in an array of P4 registers
** that are used as an unpacked index key.
**
** Reposition cursor P1 so that  it points to the largest entry that
** is less than the key value. If there are no records less than
** the key and P2 is not zero, then jump to P2.
**
** This opcode leaves the cursor configured to move in reverse order,
** from the end toward the beginning.  In other words, the cursor is
** configured to use Prev, not Next.
**
** See also: Found, NotFound, SeekGt, SeekGe, SeekLe
*/
/* Opcode: SeekLE P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
** use the value in register P3 as a key. If cursor P1 refers
** to an SQL index, then P3 is the first in an array of P4 registers
** that are used as an unpacked index key.
**
** Reposition cursor P1 so that it points to the largest entry that
** is less than or equal to the key value. If there are no records
** less than or equal to the key and P2 is not zero, then jump to P2.
**
** This opcode leaves the cursor configured to move in reverse order,
** from the end toward the beginning.  In other words, the cursor is
** configured to use Prev, not Next.
**
** If the cursor P1 was opened using the OPFLAG_SEEKEQ flag, then this
** opcode will either land on a record that exactly matches the key, or
** else it will cause a jump to P2.  When the cursor is OPFLAG_SEEKEQ,
** this opcode must be followed by an IdxLE opcode with the same arguments.
** The IdxGE opcode will be skipped if this opcode succeeds, but the
** IdxGE opcode will be used on subsequent loop iterations.  The
** OPFLAG_SEEKEQ flags is a hint to the btree layer to say that this
** is an equality search.
**
** See also: Found, NotFound, SeekGt, SeekGe, SeekLt
*/
case OP_SeekLT:         /* jump0, in3, group, ncycle */
case OP_SeekLE:         /* jump0, in3, group, ncycle */
case OP_SeekGE:         /* jump0, in3, group, ncycle */
case OP_SeekGT: {       /* jump0, in3, group, ncycle */
  int res;           /* Comparison result */
  int oc;            /* Opcode */
  VdbeCursor *pC;    /* The cursor to seek */
  UnpackedRecord r;  /* The key to seek for */
  int nField;        /* Number of columns or fields in the key */
  i64 iKey;          /* The rowid we are to seek to */
  int eqOnly;        /* Only interested in == results */

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p2!=0 );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( OP_SeekLE == OP_SeekLT+1 );
  assert( OP_SeekGE == OP_SeekLT+2 );
  assert( OP_SeekGT == OP_SeekLT+3 );
  assert( pC->isOrdered );
  assert( pC->uc.pCursor!=0 );
  oc = pOp->opcode;
  eqOnly = 0;
  pC->nullRow = 0;
#ifdef SQLITE_DEBUG
  pC->seekOp = pOp->opcode;
#endif

  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;
  if( pC->isTable ){
    u16 flags3, newType;
    /* The OPFLAG_SEEKEQ/BTREE_SEEK_EQ flag is only set on index cursors */
    assert( sqlite3BtreeCursorHasHint(pC->uc.pCursor, BTREE_SEEK_EQ)==0
              || CORRUPT_DB );

    /* The input value in P3 might be of any type: integer, real, string,
    ** blob, or NULL.  But it needs to be an integer before we can do
    ** the seek, so convert it. */
    pIn3 = &aMem[pOp->p3];
    flags3 = pIn3->flags;
    if( (flags3 & (MEM_Int|MEM_Real|MEM_IntReal|MEM_Str))==MEM_Str ){
      applyNumericAffinity(pIn3, 0);
    }
    iKey = sqlite3VdbeIntValue(pIn3); /* Get the integer key value */
    newType = pIn3->flags; /* Record the type after applying numeric affinity */
    pIn3->flags = flags3;  /* But convert the type back to its original */

    /* If the P3 value could not be converted into an integer without
    ** loss of information, then special processing is required... */
    if( (newType & (MEM_Int|MEM_IntReal))==0 ){
      int c;
      if( (newType & MEM_Real)==0 ){
        if( (newType & MEM_Null) || oc>=OP_SeekGE ){
          VdbeBranchTaken(1,2);
          goto jump_to_p2;
        }else{
          rc = sqlite3BtreeLast(pC->uc.pCursor, &res);
          if( rc!=SQLITE_OK ) goto abort_due_to_error;
          goto seek_not_found;
        }
      }
      c = sqlite3IntFloatCompare(iKey, pIn3->u.r);

      /* If the approximation iKey is larger than the actual real search
      ** term, substitute >= for > and < for <=. e.g. if the search term
      ** is 4.9 and the integer approximation 5:
      **
      **        (x >  4.9)    ->     (x >= 5)
      **        (x <= 4.9)    ->     (x <  5)
      */
      if( c>0 ){
        assert( OP_SeekGE==(OP_SeekGT-1) );
        assert( OP_SeekLT==(OP_SeekLE-1) );
        assert( (OP_SeekLE & 0x0001)==(OP_SeekGT & 0x0001) );
        if( (oc & 0x0001)==(OP_SeekGT & 0x0001) ) oc--;
      }

      /* If the approximation iKey is smaller than the actual real search
      ** term, substitute <= for < and > for >=.  */
      else if( c<0 ){
        assert( OP_SeekLE==(OP_SeekLT+1) );
        assert( OP_SeekGT==(OP_SeekGE+1) );
        assert( (OP_SeekLT & 0x0001)==(OP_SeekGE & 0x0001) );
        if( (oc & 0x0001)==(OP_SeekLT & 0x0001) ) oc++;
      }
    }
    rc = sqlite3BtreeTableMoveto(pC->uc.pCursor, (u64)iKey, 0, &res);
    pC->movetoTarget = iKey;  /* Used by OP_Delete */
    if( rc!=SQLITE_OK ){
      goto abort_due_to_error;
    }
  }else{
    /* For a cursor with the OPFLAG_SEEKEQ/BTREE_SEEK_EQ hint, only the
    ** OP_SeekGE and OP_SeekLE opcodes are allowed, and these must be
    ** immediately followed by an OP_IdxGT or OP_IdxLT opcode, respectively,
    ** with the same key.
    */
    if( sqlite3BtreeCursorHasHint(pC->uc.pCursor, BTREE_SEEK_EQ) ){
      eqOnly = 1;
      assert( pOp->opcode==OP_SeekGE || pOp->opcode==OP_SeekLE );
      assert( pOp[1].opcode==OP_IdxLT || pOp[1].opcode==OP_IdxGT );
      assert( pOp->opcode==OP_SeekGE || pOp[1].opcode==OP_IdxLT );
      assert( pOp->opcode==OP_SeekLE || pOp[1].opcode==OP_IdxGT );
      assert( pOp[1].p1==pOp[0].p1 );
      assert( pOp[1].p2==pOp[0].p2 );
      assert( pOp[1].p3==pOp[0].p3 );
      assert( pOp[1].p4.i==pOp[0].p4.i );
    }

    nField = pOp->p4.i;
    assert( pOp->p4type==P4_INT32 );
    assert( nField>0 );
    r.pKeyInfo = pC->pKeyInfo;
    r.nField = (u16)nField;

    /* The next line of code computes as follows, only faster:
    **   if( oc==OP_SeekGT || oc==OP_SeekLE ){
    **     r.default_rc = -1;
    **   }else{
    **     r.default_rc = +1;
    **   }
    */
    r.default_rc = ((1 & (oc - OP_SeekLT)) ? -1 : +1);
    assert( oc!=OP_SeekGT || r.default_rc==-1 );
    assert( oc!=OP_SeekLE || r.default_rc==-1 );
    assert( oc!=OP_SeekGE || r.default_rc==+1 );
    assert( oc!=OP_SeekLT || r.default_rc==+1 );

    r.aMem = &aMem[pOp->p3];
#ifdef SQLITE_DEBUG
    {
      int i;
      for(i=0; i<r.nField; i++){
        assert( memIsValid(&r.aMem[i]) );
        if( i>0 ) REGISTER_TRACE(pOp->p3+i, &r.aMem[i]);
      }
    }
#endif
    r.eqSeen = 0;
    rc = sqlite3BtreeIndexMoveto(pC->uc.pCursor, &r, &res);
    if( rc!=SQLITE_OK ){
      goto abort_due_to_error;
    }
    if( eqOnly && r.eqSeen==0 ){
      assert( res!=0 );
      goto seek_not_found;
    }
  }
#ifdef SQLITE_TEST
  sqlite3_search_count++;
#endif
  if( oc>=OP_SeekGE ){  assert( oc==OP_SeekGE || oc==OP_SeekGT );
    if( res<0 || (res==0 && oc==OP_SeekGT) ){

sqlite3.c  view on Meta::CPAN

        }else{
          goto abort_due_to_error;
        }
      }
    }else{
      res = 0;
    }
  }else{
    assert( oc==OP_SeekLT || oc==OP_SeekLE );
    if( res>0 || (res==0 && oc==OP_SeekLT) ){
      res = 0;
      rc = sqlite3BtreePrevious(pC->uc.pCursor, 0);
      if( rc!=SQLITE_OK ){
        if( rc==SQLITE_DONE ){
          rc = SQLITE_OK;
          res = 1;
        }else{
          goto abort_due_to_error;
        }
      }
    }else{
      /* res might be negative because the table is empty.  Check to
      ** see if this is the case.
      */
      res = sqlite3BtreeEof(pC->uc.pCursor);
    }
  }
seek_not_found:
  assert( pOp->p2>0 );
  VdbeBranchTaken(res!=0,2);
  if( res ){
    goto jump_to_p2;
  }else if( eqOnly ){
    assert( pOp[1].opcode==OP_IdxLT || pOp[1].opcode==OP_IdxGT );
    pOp++; /* Skip the OP_IdxLt or OP_IdxGT that follows */
  }
  break;
}


/* Opcode: SeekScan  P1 P2 * * P5
** Synopsis: Scan-ahead up to P1 rows
**
** This opcode is a prefix opcode to OP_SeekGE.  In other words, this
** opcode must be immediately followed by OP_SeekGE. This constraint is
** checked by assert() statements.
**
** This opcode uses the P1 through P4 operands of the subsequent
** OP_SeekGE.  In the text that follows, the operands of the subsequent
** OP_SeekGE opcode are denoted as SeekOP.P1 through SeekOP.P4.   Only
** the P1, P2 and P5 operands of this opcode are also used, and  are called
** This.P1, This.P2 and This.P5.
**
** This opcode helps to optimize IN operators on a multi-column index
** where the IN operator is on the later terms of the index by avoiding
** unnecessary seeks on the btree, substituting steps to the next row
** of the b-tree instead.  A correct answer is obtained if this opcode
** is omitted or is a no-op.
**
** The SeekGE.P3 and SeekGE.P4 operands identify an unpacked key which
** is the desired entry that we want the cursor SeekGE.P1 to be pointing
** to.  Call this SeekGE.P3/P4 row the "target".
**
** If the SeekGE.P1 cursor is not currently pointing to a valid row,
** then this opcode is a no-op and control passes through into the OP_SeekGE.
**
** If the SeekGE.P1 cursor is pointing to a valid row, then that row
** might be the target row, or it might be near and slightly before the
** target row, or it might be after the target row.  If the cursor is
** currently before the target row, then this opcode attempts to position
** the cursor on or after the target row by invoking sqlite3BtreeStep()
** on the cursor between 1 and This.P1 times.
**
** The This.P5 parameter is a flag that indicates what to do if the
** cursor ends up pointing at a valid row that is past the target
** row.  If This.P5 is false (0) then a jump is made to SeekGE.P2.  If
** This.P5 is true (non-zero) then a jump is made to This.P2.  The P5==0
** case occurs when there are no inequality constraints to the right of
** the IN constraint.  The jump to SeekGE.P2 ends the loop.  The P5!=0 case
** occurs when there are inequality constraints to the right of the IN
** operator.  In that case, the This.P2 will point either directly to or
** to setup code prior to the OP_IdxGT or OP_IdxGE opcode that checks for
** loop terminate.
**
** Possible outcomes from this opcode:<ol>
**
** <li> If the cursor is initially not pointed to any valid row, then
**      fall through into the subsequent OP_SeekGE opcode.
**
** <li> If the cursor is left pointing to a row that is before the target
**      row, even after making as many as This.P1 calls to
**      sqlite3BtreeNext(), then also fall through into OP_SeekGE.
**
** <li> If the cursor is left pointing at the target row, either because it
**      was at the target row to begin with or because one or more
**      sqlite3BtreeNext() calls moved the cursor to the target row,
**      then jump to This.P2..,
**
** <li> If the cursor started out before the target row and a call to
**      to sqlite3BtreeNext() moved the cursor off the end of the index
**      (indicating that the target row definitely does not exist in the
**      btree) then jump to SeekGE.P2, ending the loop.
**
** <li> If the cursor ends up on a valid row that is past the target row
**      (indicating that the target row does not exist in the btree) then
**      jump to SeekOP.P2 if This.P5==0 or to This.P2 if This.P5>0.
** </ol>
*/
case OP_SeekScan: {          /* ncycle */
  VdbeCursor *pC;
  int res;
  int nStep;
  UnpackedRecord r;

  assert( pOp[1].opcode==OP_SeekGE );

  /* If pOp->p5 is clear, then pOp->p2 points to the first instruction past the
  ** OP_IdxGT that follows the OP_SeekGE. Otherwise, it points to the first
  ** opcode past the OP_SeekGE itself.  */
  assert( pOp->p2>=(int)(pOp-aOp)+2 );
#ifdef SQLITE_DEBUG
  if( pOp->p5==0 ){
    /* There are no inequality constraints following the IN constraint. */
    assert( pOp[1].p1==aOp[pOp->p2-1].p1 );
    assert( pOp[1].p2==aOp[pOp->p2-1].p2 );
    assert( pOp[1].p3==aOp[pOp->p2-1].p3 );
    assert( aOp[pOp->p2-1].opcode==OP_IdxGT
         || aOp[pOp->p2-1].opcode==OP_IdxGE );
    testcase( aOp[pOp->p2-1].opcode==OP_IdxGE );
  }else{
    /* There are inequality constraints.  */
    assert( pOp->p2==(int)(pOp-aOp)+2 );
    assert( aOp[pOp->p2-1].opcode==OP_SeekGE );
  }
#endif

  assert( pOp->p1>0 );
  pC = p->apCsr[pOp[1].p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( !pC->isTable );
  if( !sqlite3BtreeCursorIsValidNN(pC->uc.pCursor) ){
#ifdef SQLITE_DEBUG
     if( db->flags&SQLITE_VdbeTrace ){
       printf("... cursor not valid - fall through\n");
     }
#endif
    break;
  }
  nStep = pOp->p1;
  assert( nStep>=1 );
  r.pKeyInfo = pC->pKeyInfo;
  r.nField = (u16)pOp[1].p4.i;
  r.default_rc = 0;
  r.aMem = &aMem[pOp[1].p3];
#ifdef SQLITE_DEBUG
  {
    int i;
    for(i=0; i<r.nField; i++){
      assert( memIsValid(&r.aMem[i]) );
      REGISTER_TRACE(pOp[1].p3+i, &aMem[pOp[1].p3+i]);
    }
  }
#endif
  res = 0;  /* Not needed.  Only used to silence a warning. */
  while(1){
    rc = sqlite3VdbeIdxKeyCompare(db, pC, &r, &res);
    if( rc ) goto abort_due_to_error;
    if( res>0 && pOp->p5==0 ){
      seekscan_search_fail:
      /* Jump to SeekGE.P2, ending the loop */
#ifdef SQLITE_DEBUG
      if( db->flags&SQLITE_VdbeTrace ){
        printf("... %d steps and then skip\n", pOp->p1 - nStep);
      }
#endif
      VdbeBranchTaken(1,3);
      pOp++;
      goto jump_to_p2;
    }
    if( res>=0 ){
      /* Jump to This.P2, bypassing the OP_SeekGE opcode */
#ifdef SQLITE_DEBUG
      if( db->flags&SQLITE_VdbeTrace ){
        printf("... %d steps and then success\n", pOp->p1 - nStep);
      }
#endif
      VdbeBranchTaken(2,3);
      goto jump_to_p2;
      break;
    }
    if( nStep<=0 ){
#ifdef SQLITE_DEBUG
      if( db->flags&SQLITE_VdbeTrace ){
        printf("... fall through after %d steps\n", pOp->p1);
      }
#endif
      VdbeBranchTaken(0,3);
      break;
    }
    nStep--;
    pC->cacheStatus = CACHE_STALE;
    rc = sqlite3BtreeNext(pC->uc.pCursor, 0);
    if( rc ){
      if( rc==SQLITE_DONE ){
        rc = SQLITE_OK;
        goto seekscan_search_fail;
      }else{
        goto abort_due_to_error;
      }
    }
  }

  break;
}


/* Opcode: SeekHit P1 P2 P3 * *
** Synopsis: set P2<=seekHit<=P3
**
** Increase or decrease the seekHit value for cursor P1, if necessary,
** so that it is no less than P2 and no greater than P3.
**
** The seekHit integer represents the maximum of terms in an index for which
** there is known to be at least one match.  If the seekHit value is smaller
** than the total number of equality terms in an index lookup, then the
** OP_IfNoHope opcode might run to see if the IN loop can be abandoned
** early, thus saving work.  This is part of the IN-early-out optimization.
**
** P1 must be a valid b-tree cursor.
*/
case OP_SeekHit: {           /* ncycle */
  VdbeCursor *pC;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pOp->p3>=pOp->p2 );
  if( pC->seekHit<pOp->p2 ){
#ifdef SQLITE_DEBUG
    if( db->flags&SQLITE_VdbeTrace ){
      printf("seekHit changes from %d to %d\n", pC->seekHit, pOp->p2);
    }
#endif
    pC->seekHit = pOp->p2;
  }else if( pC->seekHit>pOp->p3 ){
#ifdef SQLITE_DEBUG
    if( db->flags&SQLITE_VdbeTrace ){
      printf("seekHit changes from %d to %d\n", pC->seekHit, pOp->p3);
    }
#endif
    pC->seekHit = pOp->p3;
  }
  break;
}

/* Opcode: IfNotOpen P1 P2 * * *
** Synopsis: if( !csr[P1] ) goto P2
**
** If cursor P1 is not open or if P1 is set to a NULL row using the
** OP_NullRow opcode, then jump to instruction P2. Otherwise, fall through.
*/
case OP_IfNotOpen: {        /* jump */
  VdbeCursor *pCur;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pCur = p->apCsr[pOp->p1];
  VdbeBranchTaken(pCur==0 || pCur->nullRow, 2);
  if( pCur==0 || pCur->nullRow ){
    goto jump_to_p2_and_check_for_interrupt;
  }
  break;
}

/* Opcode: Found P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
** P4>0 then register P3 is the first of P4 registers that form an unpacked
** record.
**
** Cursor P1 is on an index btree.  If the record identified by P3 and P4
** is a prefix of any entry in P1 then a jump is made to P2 and
** P1 is left pointing at the matching entry.
**
** This operation leaves the cursor in a state where it can be
** advanced in the forward direction.  The Next instruction will work,
** but not the Prev instruction.
**
** See also: NotFound, NoConflict, NotExists. SeekGe
*/
/* Opcode: NotFound P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
** P4>0 then register P3 is the first of P4 registers that form an unpacked
** record.
**
** Cursor P1 is on an index btree.  If the record identified by P3 and P4
** is not the prefix of any entry in P1 then a jump is made to P2.  If P1
** does contain an entry whose prefix matches the P3/P4 record then control
** falls through to the next instruction and P1 is left pointing at the
** matching entry.
**
** This operation leaves the cursor in a state where it cannot be
** advanced in either direction.  In other words, the Next and Prev
** opcodes do not work after this operation.
**
** See also: Found, NotExists, NoConflict, IfNoHope
*/
/* Opcode: IfNoHope P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** Register P3 is the first of P4 registers that form an unpacked
** record.  Cursor P1 is an index btree.  P2 is a jump destination.
** In other words, the operands to this opcode are the same as the
** operands to OP_NotFound and OP_IdxGT.
**
** This opcode is an optimization attempt only.  If this opcode always
** falls through, the correct answer is still obtained, but extra work
** is performed.
**
** A value of N in the seekHit flag of cursor P1 means that there exists
** a key P3:N that will match some record in the index.  We want to know
** if it is possible for a record P3:P4 to match some record in the
** index.  If it is not possible, we can skip some work.  So if seekHit
** is less than P4, attempt to find out if a match is possible by running
** OP_NotFound.
**
** This opcode is used in IN clause processing for a multi-column key.
** If an IN clause is attached to an element of the key other than the
** left-most element, and if there are no matches on the most recent
** seek over the whole key, then it might be that one of the key element
** to the left is prohibiting a match, and hence there is "no hope" of
** any match regardless of how many IN clause elements are checked.
** In such a case, we abandon the IN clause search early, using this
** opcode.  The opcode name comes from the fact that the
** jump is taken if there is "no hope" of achieving a match.
**
** See also: NotFound, SeekHit
*/
/* Opcode: NoConflict P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** If P4==0 then register P3 holds a blob constructed by MakeRecord.  If
** P4>0 then register P3 is the first of P4 registers that form an unpacked
** record.
**
** Cursor P1 is on an index btree.  If the record identified by P3 and P4
** contains any NULL value, jump immediately to P2.  If all terms of the
** record are not-NULL then a check is done to determine if any row in the
** P1 index btree has a matching key prefix.  If there are no matches, jump
** immediately to P2.  If there is a match, fall through and leave the P1
** cursor pointing to the matching row.
**
** This opcode is similar to OP_NotFound with the exceptions that the
** branch is always taken if any part of the search key input is NULL.
**
** This operation leaves the cursor in a state where it cannot be
** advanced in either direction.  In other words, the Next and Prev
** opcodes do not work after this operation.
**
** See also: NotFound, Found, NotExists
*/
case OP_IfNoHope: {     /* jump, in3, ncycle */
  VdbeCursor *pC;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
#ifdef SQLITE_DEBUG
  if( db->flags&SQLITE_VdbeTrace ){
    printf("seekHit is %d\n", pC->seekHit);
  }
#endif
  if( pC->seekHit>=pOp->p4.i ) break;
  /* Fall through into OP_NotFound */
  /* no break */ deliberate_fall_through
}
case OP_NoConflict:     /* jump, in3, ncycle */
case OP_NotFound:       /* jump, in3, ncycle */
case OP_Found: {        /* jump, in3, ncycle */
  int alreadyExists;
  int ii;
  VdbeCursor *pC;
  UnpackedRecord *pIdxKey;
  UnpackedRecord r;

#ifdef SQLITE_TEST
  if( pOp->opcode!=OP_NoConflict ) sqlite3_found_count++;
#endif

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p4type==P4_INT32 );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
#ifdef SQLITE_DEBUG
  pC->seekOp = pOp->opcode;
#endif
  r.aMem = &aMem[pOp->p3];
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pC->uc.pCursor!=0 );
  assert( pC->isTable==0 );
  r.nField = (u16)pOp->p4.i;
  if( r.nField>0 ){
    /* Key values in an array of registers */
    r.pKeyInfo = pC->pKeyInfo;
    r.default_rc = 0;
#ifdef SQLITE_DEBUG
    (void)sqlite3FaultSim(50);  /* For use by --counter in TH3 */
    for(ii=0; ii<r.nField; ii++){
      assert( memIsValid(&r.aMem[ii]) );
      assert( (r.aMem[ii].flags & MEM_Zero)==0 || r.aMem[ii].n==0 );
      if( ii ) REGISTER_TRACE(pOp->p3+ii, &r.aMem[ii]);
    }
#endif
    rc = sqlite3BtreeIndexMoveto(pC->uc.pCursor, &r, &pC->seekResult);
  }else{
    /* Composite key generated by OP_MakeRecord */
    assert( r.aMem->flags & MEM_Blob );
    assert( pOp->opcode!=OP_NoConflict );
    rc = ExpandBlob(r.aMem);
    assert( rc==SQLITE_OK || rc==SQLITE_NOMEM );
    if( rc ) goto no_mem;
    pIdxKey = sqlite3VdbeAllocUnpackedRecord(pC->pKeyInfo);
    if( pIdxKey==0 ) goto no_mem;
    sqlite3VdbeRecordUnpack(r.aMem->n, r.aMem->z, pIdxKey);
    pIdxKey->default_rc = 0;
    rc = sqlite3BtreeIndexMoveto(pC->uc.pCursor, pIdxKey, &pC->seekResult);
    sqlite3DbFreeNN(db, pIdxKey);
  }
  if( rc!=SQLITE_OK ){
    goto abort_due_to_error;
  }
  alreadyExists = (pC->seekResult==0);
  pC->nullRow = 1-alreadyExists;
  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;
  if( pOp->opcode==OP_Found ){
    VdbeBranchTaken(alreadyExists!=0,2);
    if( alreadyExists ) goto jump_to_p2;
  }else{
    if( !alreadyExists ){
      VdbeBranchTaken(1,2);
      goto jump_to_p2;
    }
    if( pOp->opcode==OP_NoConflict ){
      /* For the OP_NoConflict opcode, take the jump if any of the
      ** input fields are NULL, since any key with a NULL will not
      ** conflict */
      for(ii=0; ii<r.nField; ii++){
        if( r.aMem[ii].flags & MEM_Null ){
          VdbeBranchTaken(1,2);
          goto jump_to_p2;
        }
      }
    }
    VdbeBranchTaken(0,2);
    if( pOp->opcode==OP_IfNoHope ){
      pC->seekHit = pOp->p4.i;
    }
  }
  break;
}

/* Opcode: SeekRowid P1 P2 P3 * *
** Synopsis: intkey=r[P3]
**
** P1 is the index of a cursor open on an SQL table btree (with integer
** keys).  If register P3 does not contain an integer or if P1 does not
** contain a record with rowid P3 then jump immediately to P2.
** Or, if P2 is 0, raise an SQLITE_CORRUPT error. If P1 does contain
** a record with rowid P3 then
** leave the cursor pointing at that record and fall through to the next
** instruction.
**
** The OP_NotExists opcode performs the same operation, but with OP_NotExists
** the P3 register must be guaranteed to contain an integer value.  With this
** opcode, register P3 might not contain an integer.
**
** The OP_NotFound opcode performs the same operation on index btrees
** (with arbitrary multi-value keys).
**
** This opcode leaves the cursor in a state where it cannot be advanced
** in either direction.  In other words, the Next and Prev opcodes will
** not work following this opcode.
**
** See also: Found, NotFound, NoConflict, SeekRowid
*/
/* Opcode: NotExists P1 P2 P3 * *
** Synopsis: intkey=r[P3]
**
** P1 is the index of a cursor open on an SQL table btree (with integer
** keys).  P3 is an integer rowid.  If P1 does not contain a record with
** rowid P3 then jump immediately to P2.  Or, if P2 is 0, raise an
** SQLITE_CORRUPT error. If P1 does contain a record with rowid P3 then
** leave the cursor pointing at that record and fall through to the next
** instruction.
**
** The OP_SeekRowid opcode performs the same operation but also allows the
** P3 register to contain a non-integer value, in which case the jump is
** always taken.  This opcode requires that P3 always contain an integer.
**
** The OP_NotFound opcode performs the same operation on index btrees
** (with arbitrary multi-value keys).
**
** This opcode leaves the cursor in a state where it cannot be advanced
** in either direction.  In other words, the Next and Prev opcodes will
** not work following this opcode.
**
** See also: Found, NotFound, NoConflict, SeekRowid
*/
case OP_SeekRowid: {        /* jump0, in3, ncycle */
  VdbeCursor *pC;
  BtCursor *pCrsr;
  int res;
  u64 iKey;

  pIn3 = &aMem[pOp->p3];
  testcase( pIn3->flags & MEM_Int );
  testcase( pIn3->flags & MEM_IntReal );
  testcase( pIn3->flags & MEM_Real );
  testcase( (pIn3->flags & (MEM_Str|MEM_Int))==MEM_Str );
  if( (pIn3->flags & (MEM_Int|MEM_IntReal))==0 ){
    /* If pIn3->u.i does not contain an integer, compute iKey as the
    ** integer value of pIn3.  Jump to P2 if pIn3 cannot be converted
    ** into an integer without loss of information.  Take care to avoid
    ** changing the datatype of pIn3, however, as it is used by other
    ** parts of the prepared statement. */
    Mem x = pIn3[0];
    applyAffinity(&x, SQLITE_AFF_NUMERIC, encoding);
    if( (x.flags & MEM_Int)==0 ) goto jump_to_p2;
    iKey = x.u.i;
    goto notExistsWithKey;
  }
  /* Fall through into OP_NotExists */
  /* no break */ deliberate_fall_through
case OP_NotExists:          /* jump, in3, ncycle */
  pIn3 = &aMem[pOp->p3];
  assert( (pIn3->flags & MEM_Int)!=0 || pOp->opcode==OP_SeekRowid );
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  iKey = pIn3->u.i;
notExistsWithKey:
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
#ifdef SQLITE_DEBUG
  if( pOp->opcode==OP_SeekRowid ) pC->seekOp = OP_SeekRowid;
#endif
  assert( pC->isTable );
  assert( pC->eCurType==CURTYPE_BTREE );
  pCrsr = pC->uc.pCursor;
  assert( pCrsr!=0 );
  res = 0;
  rc = sqlite3BtreeTableMoveto(pCrsr, iKey, 0, &res);
  assert( rc==SQLITE_OK || res==0 );
  pC->movetoTarget = iKey;  /* Used by OP_Delete */
  pC->nullRow = 0;
  pC->cacheStatus = CACHE_STALE;
  pC->deferredMoveto = 0;
  VdbeBranchTaken(res!=0,2);
  pC->seekResult = res;
  if( res!=0 ){
    assert( rc==SQLITE_OK );
    if( pOp->p2==0 ){
      rc = SQLITE_CORRUPT_BKPT;
    }else{
      goto jump_to_p2;
    }
  }
  if( rc ) goto abort_due_to_error;
  break;
}

/* Opcode: Sequence P1 P2 * * *
** Synopsis: r[P2]=cursor[P1].ctr++
**
** Find the next available sequence number for cursor P1.
** Write the sequence number into register P2.
** The sequence number on the cursor is incremented after this
** instruction.
*/
case OP_Sequence: {           /* out2 */
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( p->apCsr[pOp->p1]!=0 );
  assert( p->apCsr[pOp->p1]->eCurType!=CURTYPE_VTAB );
  pOut = out2Prerelease(p, pOp);
  pOut->u.i = p->apCsr[pOp->p1]->seqCount++;
  break;
}


/* Opcode: NewRowid P1 P2 P3 * *
** Synopsis: r[P2]=rowid
**
** Get a new integer record number (a.k.a "rowid") used as the key to a table.
** The record number is not previously used as a key in the database
** table that cursor P1 points to.  The new record number is written
** written to register P2.
**
** If P3>0 then P3 is a register in the root frame of this VDBE that holds
** the largest previously generated record number. No new record numbers are
** allowed to be less than this value. When this value reaches its maximum,
** an SQLITE_FULL error is generated. The P3 register is updated with the '
** generated record number. This P3 mechanism is used to help implement the
** AUTOINCREMENT feature.
*/
case OP_NewRowid: {           /* out2 */
  i64 v;                 /* The new rowid */
  VdbeCursor *pC;        /* Cursor of table to get the new rowid */
  int res;               /* Result of an sqlite3BtreeLast() */
  int cnt;               /* Counter to limit the number of searches */
#ifndef SQLITE_OMIT_AUTOINCREMENT
  Mem *pMem;             /* Register holding largest rowid for AUTOINCREMENT */
  VdbeFrame *pFrame;     /* Root frame of VDBE */
#endif

  v = 0;
  res = 0;
  pOut = out2Prerelease(p, pOp);
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->isTable );
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pC->uc.pCursor!=0 );
  {
    /* The next rowid or record number (different terms for the same
    ** thing) is obtained in a two-step algorithm.
    **
    ** First we attempt to find the largest existing rowid and add one
    ** to that.  But if the largest existing rowid is already the maximum
    ** positive integer, we have to fall through to the second
    ** probabilistic algorithm
    **
    ** The second algorithm is to select a rowid at random and see if
    ** it already exists in the table.  If it does not exist, we have
    ** succeeded.  If the random rowid does exist, we select a new one
    ** and try again, up to 100 times.
    */
    assert( pC->isTable );

#ifdef SQLITE_32BIT_ROWID
#   define MAX_ROWID 0x7fffffff
#else
    /* Some compilers complain about constants of the form 0x7fffffffffffffff.
    ** Others complain about 0x7ffffffffffffffffLL.  The following macro seems
    ** to provide the constant while making all compilers happy.
    */
#   define MAX_ROWID  (i64)( (((u64)0x7fffffff)<<32) | (u64)0xffffffff )
#endif

    if( !pC->useRandomRowid ){
      rc = sqlite3BtreeLast(pC->uc.pCursor, &res);
      if( rc!=SQLITE_OK ){
        goto abort_due_to_error;
      }
      if( res ){

sqlite3.c  view on Meta::CPAN

      /* Assert that P3 is a valid memory cell. */
      assert( pOp->p3>0 );
      if( p->pFrame ){
        for(pFrame=p->pFrame; pFrame->pParent; pFrame=pFrame->pParent);
        /* Assert that P3 is a valid memory cell. */
        assert( pOp->p3<=pFrame->nMem );
        pMem = &pFrame->aMem[pOp->p3];
      }else{
        /* Assert that P3 is a valid memory cell. */
        assert( pOp->p3<=(p->nMem+1 - p->nCursor) );
        pMem = &aMem[pOp->p3];
        memAboutToChange(p, pMem);
      }
      assert( memIsValid(pMem) );

      REGISTER_TRACE(pOp->p3, pMem);
      sqlite3VdbeMemIntegerify(pMem);
      assert( (pMem->flags & MEM_Int)!=0 );  /* mem(P3) holds an integer */
      if( pMem->u.i==MAX_ROWID || pC->useRandomRowid ){
        rc = SQLITE_FULL;   /* IMP: R-17817-00630 */
        goto abort_due_to_error;
      }
      if( v<pMem->u.i+1 ){
        v = pMem->u.i + 1;
      }
      pMem->u.i = v;
    }
#endif
    if( pC->useRandomRowid ){
      /* IMPLEMENTATION-OF: R-07677-41881 If the largest ROWID is equal to the
      ** largest possible integer (9223372036854775807) then the database
      ** engine starts picking positive candidate ROWIDs at random until
      ** it finds one that is not previously used. */
      assert( pOp->p3==0 );  /* We cannot be in random rowid mode if this is
                             ** an AUTOINCREMENT table. */
      cnt = 0;
      do{
        sqlite3_randomness(sizeof(v), &v);
        v &= (MAX_ROWID>>1); v++;  /* Ensure that v is greater than zero */
      }while(  ((rc = sqlite3BtreeTableMoveto(pC->uc.pCursor, (u64)v,
                                                 0, &res))==SQLITE_OK)
            && (res==0)
            && (++cnt<100));
      if( rc ) goto abort_due_to_error;
      if( res==0 ){
        rc = SQLITE_FULL;   /* IMP: R-38219-53002 */
        goto abort_due_to_error;
      }
      assert( v>0 );  /* EV: R-40812-03570 */
    }
    pC->deferredMoveto = 0;
    pC->cacheStatus = CACHE_STALE;
  }
  pOut->u.i = v;
  break;
}

/* Opcode: Insert P1 P2 P3 P4 P5
** Synopsis: intkey=r[P3] data=r[P2]
**
** Write an entry into the table of cursor P1.  A new entry is
** created if it doesn't already exist or the data for an existing
** entry is overwritten.  The data is the value MEM_Blob stored in register
** number P2. The key is stored in register P3. The key must
** be a MEM_Int.
**
** If the OPFLAG_NCHANGE flag of P5 is set, then the row change count is
** incremented (otherwise not).  If the OPFLAG_LASTROWID flag of P5 is set,
** then rowid is stored for subsequent return by the
** sqlite3_last_insert_rowid() function (otherwise it is unmodified).
**
** If the OPFLAG_USESEEKRESULT flag of P5 is set, the implementation might
** run faster by avoiding an unnecessary seek on cursor P1.  However,
** the OPFLAG_USESEEKRESULT flag must only be set if there have been no prior
** seeks on the cursor or if the most recent seek used a key equal to P3.
**
** If the OPFLAG_ISUPDATE flag is set, then this opcode is part of an
** UPDATE operation.  Otherwise (if the flag is clear) then this opcode
** is part of an INSERT operation.  The difference is only important to
** the update hook.
**
** Parameter P4 may point to a Table structure, or may be NULL. If it is
** not NULL, then the update-hook (sqlite3.xUpdateCallback) is invoked
** following a successful insert.
**
** (WARNING/TODO: If P1 is a pseudo-cursor and P2 is dynamically
** allocated, then ownership of P2 is transferred to the pseudo-cursor
** and register P2 becomes ephemeral.  If the cursor is changed, the
** value of register P2 will then change.  Make sure this does not
** cause any problems.)
**
** This instruction only works on tables.  The equivalent instruction
** for indices is OP_IdxInsert.
*/
case OP_Insert: {
  Mem *pData;       /* MEM cell holding data for the record to be inserted */
  Mem *pKey;        /* MEM cell holding key  for the record */
  VdbeCursor *pC;   /* Cursor to table into which insert is written */
  int seekResult;   /* Result of prior seek or 0 if no USESEEKRESULT flag */
  const char *zDb;  /* database name - used by the update hook */
  Table *pTab;      /* Table structure - used by update and pre-update hooks */
  BtreePayload x;   /* Payload to be inserted */

  pData = &aMem[pOp->p2];
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( memIsValid(pData) );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pC->deferredMoveto==0 );
  assert( pC->uc.pCursor!=0 );
  assert( (pOp->p5 & OPFLAG_ISNOOP) || pC->isTable );
  assert( pOp->p4type==P4_TABLE || pOp->p4type>=P4_STATIC );
  REGISTER_TRACE(pOp->p2, pData);
  sqlite3VdbeIncrWriteCounter(p, pC);

  pKey = &aMem[pOp->p3];
  assert( pKey->flags & MEM_Int );
  assert( memIsValid(pKey) );
  REGISTER_TRACE(pOp->p3, pKey);
  x.nKey = pKey->u.i;

  if( pOp->p4type==P4_TABLE && HAS_UPDATE_HOOK(db) ){
    assert( pC->iDb>=0 );
    zDb = db->aDb[pC->iDb].zDbSName;
    pTab = pOp->p4.pTab;
    assert( (pOp->p5 & OPFLAG_ISNOOP) || HasRowid(pTab) );
  }else{
    pTab = 0;
    zDb = 0;
  }

#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
  /* Invoke the pre-update hook, if any */
  if( pTab ){
    if( db->xPreUpdateCallback && !(pOp->p5 & OPFLAG_ISUPDATE) ){
      sqlite3VdbePreUpdateHook(p,pC,SQLITE_INSERT,zDb,pTab,x.nKey,pOp->p2,-1);
    }
    if( db->xUpdateCallback==0 || pTab->aCol==0 ){
      /* Prevent post-update hook from running in cases when it should not */
      pTab = 0;
    }
  }
  if( pOp->p5 & OPFLAG_ISNOOP ) break;
#endif

  assert( (pOp->p5 & OPFLAG_LASTROWID)==0 || (pOp->p5 & OPFLAG_NCHANGE)!=0 );
  if( pOp->p5 & OPFLAG_NCHANGE ){
    p->nChange++;
    if( pOp->p5 & OPFLAG_LASTROWID ) db->lastRowid = x.nKey;
  }
  assert( (pData->flags & (MEM_Blob|MEM_Str))!=0 || pData->n==0 );
  x.pData = pData->z;
  x.nData = pData->n;
  seekResult = ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0);
  if( pData->flags & MEM_Zero ){
    x.nZero = pData->u.nZero;
  }else{
    x.nZero = 0;
  }
  x.pKey = 0;
  assert( BTREE_PREFORMAT==OPFLAG_PREFORMAT );
  rc = sqlite3BtreeInsert(pC->uc.pCursor, &x,
      (pOp->p5 & (OPFLAG_APPEND|OPFLAG_SAVEPOSITION|OPFLAG_PREFORMAT)),
      seekResult
  );
  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;
  colCacheCtr++;

  /* Invoke the update-hook if required. */
  if( rc ) goto abort_due_to_error;
  if( pTab ){
    assert( db->xUpdateCallback!=0 );
    assert( pTab->aCol!=0 );
    db->xUpdateCallback(db->pUpdateArg,
           (pOp->p5 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT,
           zDb, pTab->zName, x.nKey);
  }
  break;
}

/* Opcode: RowCell P1 P2 P3 * *
**
** P1 and P2 are both open cursors. Both must be opened on the same type
** of table - intkey or index. This opcode is used as part of copying
** the current row from P2 into P1. If the cursors are opened on intkey
** tables, register P3 contains the rowid to use with the new record in
** P1. If they are opened on index tables, P3 is not used.
**
** This opcode must be followed by either an Insert or InsertIdx opcode
** with the OPFLAG_PREFORMAT flag set to complete the insert operation.
*/
case OP_RowCell: {
  VdbeCursor *pDest;              /* Cursor to write to */
  VdbeCursor *pSrc;               /* Cursor to read from */
  i64 iKey;                       /* Rowid value to insert with */
  assert( pOp[1].opcode==OP_Insert || pOp[1].opcode==OP_IdxInsert );
  assert( pOp[1].opcode==OP_Insert    || pOp->p3==0 );
  assert( pOp[1].opcode==OP_IdxInsert || pOp->p3>0 );
  assert( pOp[1].p5 & OPFLAG_PREFORMAT );
  pDest = p->apCsr[pOp->p1];
  pSrc = p->apCsr[pOp->p2];
  iKey = pOp->p3 ? aMem[pOp->p3].u.i : 0;
  rc = sqlite3BtreeTransferRow(pDest->uc.pCursor, pSrc->uc.pCursor, iKey);
  if( rc!=SQLITE_OK ) goto abort_due_to_error;
  break;
};

/* Opcode: Delete P1 P2 P3 P4 P5
**
** Delete the record at which the P1 cursor is currently pointing.
**
** If the OPFLAG_SAVEPOSITION bit of the P5 parameter is set, then
** the cursor will be left pointing at  either the next or the previous
** record in the table. If it is left pointing at the next record, then
** the next Next instruction will be a no-op. As a result, in this case
** it is ok to delete a record from within a Next loop. If
** OPFLAG_SAVEPOSITION bit of P5 is clear, then the cursor will be
** left in an undefined state.
**
** If the OPFLAG_AUXDELETE bit is set on P5, that indicates that this
** delete is one of several associated with deleting a table row and
** all its associated index entries.  Exactly one of those deletes is
** the "primary" delete.  The others are all on OPFLAG_FORDELETE
** cursors or else are marked with the AUXDELETE flag.
**
** If the OPFLAG_NCHANGE (0x01) flag of P2 (NB: P2 not P5) is set, then
** the row change count is incremented (otherwise not).
**
** If the OPFLAG_ISNOOP (0x40) flag of P2 (not P5!) is set, then the
** pre-update-hook for deletes is run, but the btree is otherwise unchanged.
** This happens when the OP_Delete is to be shortly followed by an OP_Insert
** with the same key, causing the btree entry to be overwritten.
**
** P1 must not be pseudo-table.  It has to be a real table with
** multiple rows.
**
** If P4 is not NULL then it points to a Table object. In this case either
** the update or pre-update hook, or both, may be invoked. The P1 cursor must
** have been positioned using OP_NotFound prior to invoking this opcode in
** this case. Specifically, if one is configured, the pre-update hook is
** invoked if P4 is not NULL. The update-hook is invoked if one is configured,
** P4 is not NULL, and the OPFLAG_NCHANGE flag is set in P2.
**
** If the OPFLAG_ISUPDATE flag is set in P2, then P3 contains the address
** of the memory cell that contains the value that the rowid of the row will
** be set to by the update.
*/
case OP_Delete: {
  VdbeCursor *pC;
  const char *zDb;
  Table *pTab;
  int opflags;

  opflags = pOp->p2;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pC->uc.pCursor!=0 );
  assert( pC->deferredMoveto==0 );
  sqlite3VdbeIncrWriteCounter(p, pC);

#ifdef SQLITE_DEBUG
  if( pOp->p4type==P4_TABLE
   && HasRowid(pOp->p4.pTab)
   && pOp->p5==0
   && sqlite3BtreeCursorIsValidNN(pC->uc.pCursor)
  ){
    /* If p5 is zero, the seek operation that positioned the cursor prior to
    ** OP_Delete will have also set the pC->movetoTarget field to the rowid of
    ** the row that is being deleted */
    i64 iKey = sqlite3BtreeIntegerKey(pC->uc.pCursor);
    assert( CORRUPT_DB || pC->movetoTarget==iKey );
  }
#endif

  /* If the update-hook or pre-update-hook will be invoked, set zDb to
  ** the name of the db to pass as to it. Also set local pTab to a copy
  ** of p4.pTab. Finally, if p5 is true, indicating that this cursor was
  ** last moved with OP_Next or OP_Prev, not Seek or NotFound, set
  ** VdbeCursor.movetoTarget to the current rowid.  */
  if( pOp->p4type==P4_TABLE && HAS_UPDATE_HOOK(db) ){
    assert( pC->iDb>=0 );
    assert( pOp->p4.pTab!=0 );
    zDb = db->aDb[pC->iDb].zDbSName;
    pTab = pOp->p4.pTab;
    if( (pOp->p5 & OPFLAG_SAVEPOSITION)!=0 && pC->isTable ){
      pC->movetoTarget = sqlite3BtreeIntegerKey(pC->uc.pCursor);
    }
  }else{
    zDb = 0;
    pTab = 0;
  }

#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
  /* Invoke the pre-update-hook if required. */
  assert( db->xPreUpdateCallback==0 || pTab==pOp->p4.pTab );
  if( db->xPreUpdateCallback && pTab ){
    assert( !(opflags & OPFLAG_ISUPDATE)
         || HasRowid(pTab)==0
         || (aMem[pOp->p3].flags & MEM_Int)
    );
    sqlite3VdbePreUpdateHook(p, pC,
        (opflags & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_DELETE,
        zDb, pTab, pC->movetoTarget,
        pOp->p3, -1
    );
  }
  if( opflags & OPFLAG_ISNOOP ) break;
#endif

  /* Only flags that can be set are SAVEPOISTION and AUXDELETE */
  assert( (pOp->p5 & ~(OPFLAG_SAVEPOSITION|OPFLAG_AUXDELETE))==0 );
  assert( OPFLAG_SAVEPOSITION==BTREE_SAVEPOSITION );
  assert( OPFLAG_AUXDELETE==BTREE_AUXDELETE );

#ifdef SQLITE_DEBUG
  if( p->pFrame==0 ){
    if( pC->isEphemeral==0
        && (pOp->p5 & OPFLAG_AUXDELETE)==0
        && (pC->wrFlag & OPFLAG_FORDELETE)==0
      ){
      nExtraDelete++;
    }
    if( pOp->p2 & OPFLAG_NCHANGE ){
      nExtraDelete--;
    }
  }
#endif

  rc = sqlite3BtreeDelete(pC->uc.pCursor, pOp->p5);
  pC->cacheStatus = CACHE_STALE;
  colCacheCtr++;
  pC->seekResult = 0;
  if( rc ) goto abort_due_to_error;

  /* Invoke the update-hook if required. */
  if( opflags & OPFLAG_NCHANGE ){
    p->nChange++;
    if( db->xUpdateCallback && ALWAYS(pTab!=0) && HasRowid(pTab) ){
      db->xUpdateCallback(db->pUpdateArg, SQLITE_DELETE, zDb, pTab->zName,
          pC->movetoTarget);
      assert( pC->iDb>=0 );
    }
  }

  break;
}
/* Opcode: ResetCount * * * * *
**
** The value of the change counter is copied to the database handle
** change counter (returned by subsequent calls to sqlite3_changes()).
** Then the VMs internal change counter resets to 0.
** This is used by trigger programs.
*/
case OP_ResetCount: {
  sqlite3VdbeSetChanges(db, p->nChange);
  p->nChange = 0;
  break;
}

/* Opcode: SorterCompare P1 P2 P3 P4
** Synopsis: if key(P1)!=trim(r[P3],P4) goto P2
**
** P1 is a sorter cursor. This instruction compares a prefix of the
** record blob in register P3 against a prefix of the entry that
** the sorter cursor currently points to.  Only the first P4 fields
** of r[P3] and the sorter record are compared.
**
** If either P3 or the sorter contains a NULL in one of their significant
** fields (not counting the P4 fields at the end which are ignored) then
** the comparison is assumed to be equal.
**
** Fall through to next instruction if the two records compare equal to
** each other.  Jump to P2 if they are different.
*/
case OP_SorterCompare: {
  VdbeCursor *pC;
  int res;
  int nKeyCol;

  pC = p->apCsr[pOp->p1];
  assert( isSorter(pC) );
  assert( pOp->p4type==P4_INT32 );
  pIn3 = &aMem[pOp->p3];
  nKeyCol = pOp->p4.i;
  res = 0;
  rc = sqlite3VdbeSorterCompare(pC, pIn3, nKeyCol, &res);
  VdbeBranchTaken(res!=0,2);
  if( rc ) goto abort_due_to_error;
  if( res ) goto jump_to_p2;
  break;
};

/* Opcode: SorterData P1 P2 P3 * *
** Synopsis: r[P2]=data
**
** Write into register P2 the current sorter data for sorter cursor P1.
** Then clear the column header cache on cursor P3.
**
** This opcode is normally used to move a record out of the sorter and into
** a register that is the source for a pseudo-table cursor created using
** OpenPseudo.  That pseudo-table cursor is the one that is identified by
** parameter P3.  Clearing the P3 column cache as part of this opcode saves
** us from having to issue a separate NullRow instruction to clear that cache.
*/
case OP_SorterData: {       /* ncycle */
  VdbeCursor *pC;

  pOut = &aMem[pOp->p2];
  pC = p->apCsr[pOp->p1];
  assert( isSorter(pC) );
  rc = sqlite3VdbeSorterRowkey(pC, pOut);
  assert( rc!=SQLITE_OK || (pOut->flags & MEM_Blob) );
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  if( rc ) goto abort_due_to_error;
  p->apCsr[pOp->p3]->cacheStatus = CACHE_STALE;
  break;
}

/* Opcode: RowData P1 P2 P3 * *
** Synopsis: r[P2]=data
**
** Write into register P2 the complete row content for the row at
** which cursor P1 is currently pointing.
** There is no interpretation of the data.
** It is just copied onto the P2 register exactly as
** it is found in the database file.
**
** If cursor P1 is an index, then the content is the key of the row.
** If cursor P2 is a table, then the content extracted is the data.
**
** If the P1 cursor must be pointing to a valid row (not a NULL row)
** of a real table, not a pseudo-table.
**
** If P3!=0 then this opcode is allowed to make an ephemeral pointer
** into the database page.  That means that the content of the output
** register will be invalidated as soon as the cursor moves - including
** moves caused by other cursors that "save" the current cursors
** position in order that they can write to the same table.  If P3==0
** then a copy of the data is made into memory.  P3!=0 is faster, but
** P3==0 is safer.
**
** If P3!=0 then the content of the P2 register is unsuitable for use
** in OP_Result and any OP_Result will invalidate the P2 register content.
** The P2 register content is invalidated by opcodes like OP_Function or
** by any use of another cursor pointing to the same table.
*/
case OP_RowData: {
  VdbeCursor *pC;
  BtCursor *pCrsr;
  u32 n;

  pOut = out2Prerelease(p, pOp);

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( isSorter(pC)==0 );
  assert( pC->nullRow==0 );
  assert( pC->uc.pCursor!=0 );
  pCrsr = pC->uc.pCursor;

  /* The OP_RowData opcodes always follow OP_NotExists or
  ** OP_SeekRowid or OP_Rewind/Op_Next with no intervening instructions
  ** that might invalidate the cursor.
  ** If this were not the case, one of the following assert()s
  ** would fail.  Should this ever change (because of changes in the code
  ** generator) then the fix would be to insert a call to
  ** sqlite3VdbeCursorMoveto().
  */
  assert( pC->deferredMoveto==0 );
  assert( sqlite3BtreeCursorIsValid(pCrsr) );

  n = sqlite3BtreePayloadSize(pCrsr);
  if( n>(u32)db->aLimit[SQLITE_LIMIT_LENGTH] ){
    goto too_big;
  }
  testcase( n==0 );
  rc = sqlite3VdbeMemFromBtreeZeroOffset(pCrsr, n, pOut);
  if( rc ) goto abort_due_to_error;
  if( !pOp->p3 ) Deephemeralize(pOut);
  UPDATE_MAX_BLOBSIZE(pOut);
  REGISTER_TRACE(pOp->p2, pOut);
  break;
}

/* Opcode: Rowid P1 P2 * * *
** Synopsis: r[P2]=PX rowid of P1
**
** Store in register P2 an integer which is the key of the table entry that
** P1 is currently point to.
**
** P1 can be either an ordinary table or a virtual table.  There used to
** be a separate OP_VRowid opcode for use with virtual tables, but this
** one opcode now works for both table types.
*/
case OP_Rowid: {                 /* out2, ncycle */
  VdbeCursor *pC;
  i64 v;
  sqlite3_vtab *pVtab;
  const sqlite3_module *pModule;

  pOut = out2Prerelease(p, pOp);
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType!=CURTYPE_PSEUDO || pC->nullRow );
  if( pC->nullRow ){
    pOut->flags = MEM_Null;
    break;
  }else if( pC->deferredMoveto ){
    v = pC->movetoTarget;
#ifndef SQLITE_OMIT_VIRTUALTABLE
  }else if( pC->eCurType==CURTYPE_VTAB ){
    assert( pC->uc.pVCur!=0 );
    pVtab = pC->uc.pVCur->pVtab;
    pModule = pVtab->pModule;
    assert( pModule->xRowid );
    rc = pModule->xRowid(pC->uc.pVCur, &v);
    sqlite3VtabImportErrmsg(p, pVtab);
    if( rc ) goto abort_due_to_error;
#endif /* SQLITE_OMIT_VIRTUALTABLE */
  }else{
    assert( pC->eCurType==CURTYPE_BTREE );
    assert( pC->uc.pCursor!=0 );
    rc = sqlite3VdbeCursorRestore(pC);
    if( rc ) goto abort_due_to_error;
    if( pC->nullRow ){
      pOut->flags = MEM_Null;
      break;
    }
    v = sqlite3BtreeIntegerKey(pC->uc.pCursor);
  }
  pOut->u.i = v;
  break;
}

/* Opcode: NullRow P1 * * * *
**
** Move the cursor P1 to a null row.  Any OP_Column operations
** that occur while the cursor is on the null row will always
** write a NULL.
**
** If cursor P1 is not previously opened, open it now to a special
** pseudo-cursor that always returns NULL for every column.
*/
case OP_NullRow: {
  VdbeCursor *pC;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  if( pC==0 ){
    /* If the cursor is not already open, create a special kind of
    ** pseudo-cursor that always gives null rows. */
    pC = allocateCursor(p, pOp->p1, 1, CURTYPE_PSEUDO);
    if( pC==0 ) goto no_mem;
    pC->seekResult = 0;
    pC->isTable = 1;
    pC->noReuse = 1;
    pC->uc.pCursor = sqlite3BtreeFakeValidCursor();
  }
  pC->nullRow = 1;
  pC->cacheStatus = CACHE_STALE;
  if( pC->eCurType==CURTYPE_BTREE ){
    assert( pC->uc.pCursor!=0 );
    sqlite3BtreeClearCursor(pC->uc.pCursor);
  }
#ifdef SQLITE_DEBUG
  if( pC->seekOp==0 ) pC->seekOp = OP_NullRow;
#endif
  break;
}

/* Opcode: SeekEnd P1 * * * *
**
** Position cursor P1 at the end of the btree for the purpose of
** appending a new entry onto the btree.
**
** It is assumed that the cursor is used only for appending and so
** if the cursor is valid, then the cursor must already be pointing
** at the end of the btree and so no changes are made to
** the cursor.
*/
/* Opcode: Last P1 P2 * * *
**
** The next use of the Rowid or Column or Prev instruction for P1
** will refer to the last entry in the database table or index.
** If the table or index is empty and P2>0, then jump immediately to P2.
** If P2 is 0 or if the table or index is not empty, fall through
** to the following instruction.
**
** This opcode leaves the cursor configured to move in reverse order,
** from the end toward the beginning.  In other words, the cursor is
** configured to use Prev, not Next.
*/
case OP_SeekEnd:             /* ncycle */
case OP_Last: {              /* jump0, ncycle */
  VdbeCursor *pC;
  BtCursor *pCrsr;
  int res;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  pCrsr = pC->uc.pCursor;
  res = 0;
  assert( pCrsr!=0 );
#ifdef SQLITE_DEBUG
  pC->seekOp = pOp->opcode;
#endif
  if( pOp->opcode==OP_SeekEnd ){
    assert( pOp->p2==0 );
    pC->seekResult = -1;
    if( sqlite3BtreeCursorIsValidNN(pCrsr) ){
      break;
    }
  }
  rc = sqlite3BtreeLast(pCrsr, &res);
  pC->nullRow = (u8)res;
  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;
  if( rc ) goto abort_due_to_error;
  if( pOp->p2>0 ){
    VdbeBranchTaken(res!=0,2);
    if( res ) goto jump_to_p2;
  }
  break;
}

/* Opcode: IfSizeBetween P1 P2 P3 P4 *
**
** Let N be the approximate number of rows in the table or index
** with cursor P1 and let X be 10*log2(N) if N is positive or -1
** if N is zero.
**
** Jump to P2 if X is in between P3 and P4, inclusive.
*/
case OP_IfSizeBetween: {        /* jump */
  VdbeCursor *pC;
  BtCursor *pCrsr;
  int res;
  i64 sz;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p4type==P4_INT32 );
  assert( pOp->p3>=-1 && pOp->p3<=640*2 );
  assert( pOp->p4.i>=-1 && pOp->p4.i<=640*2 );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  pCrsr = pC->uc.pCursor;
  assert( pCrsr );
  rc = sqlite3BtreeFirst(pCrsr, &res);
  if( rc ) goto abort_due_to_error;
  if( res!=0 ){
    sz = -1;  /* -Infinity encoding */
  }else{
    sz = sqlite3BtreeRowCountEst(pCrsr);
    assert( sz>0 );
    sz = sqlite3LogEst((u64)sz);
  }
  res = sz>=pOp->p3 && sz<=pOp->p4.i;
  VdbeBranchTaken(res!=0,2);
  if( res ) goto jump_to_p2;
  break;
}


/* Opcode: SorterSort P1 P2 * * *
**
** After all records have been inserted into the Sorter object
** identified by P1, invoke this opcode to actually do the sorting.
** Jump to P2 if there are no records to be sorted.
**
** This opcode is an alias for OP_Sort and OP_Rewind that is used
** for Sorter objects.
*/
/* Opcode: Sort P1 P2 * * *
**
** This opcode does exactly the same thing as OP_Rewind except that
** it increments an undocumented global variable used for testing.
**
** Sorting is accomplished by writing records into a sorting index,
** then rewinding that index and playing it back from beginning to
** end.  We use the OP_Sort opcode instead of OP_Rewind to do the
** rewinding so that the global variable will be incremented and
** regression tests can determine whether or not the optimizer is
** correctly optimizing out sorts.
*/
case OP_SorterSort:    /* jump ncycle */
case OP_Sort: {        /* jump ncycle */
#ifdef SQLITE_TEST
  sqlite3_sort_count++;
  sqlite3_search_count--;
#endif
  p->aCounter[SQLITE_STMTSTATUS_SORT]++;
  /* Fall through into OP_Rewind */
  /* no break */ deliberate_fall_through
}
/* Opcode: Rewind P1 P2 * * *
**
** The next use of the Rowid or Column or Next instruction for P1
** will refer to the first entry in the database table or index.
** If the table or index is empty, jump immediately to P2.
** If the table or index is not empty, fall through to the following
** instruction.
**
** If P2 is zero, that is an assertion that the P1 table is never
** empty and hence the jump will never be taken.
**
** This opcode leaves the cursor configured to move in forward order,
** from the beginning toward the end.  In other words, the cursor is
** configured to use Next, not Prev.
*/
case OP_Rewind: {        /* jump0, ncycle */
  VdbeCursor *pC;
  BtCursor *pCrsr;
  int res;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p5==0 );
  assert( pOp->p2>=0 && pOp->p2<p->nOp );

  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( isSorter(pC)==(pOp->opcode==OP_SorterSort) );
  res = 1;
#ifdef SQLITE_DEBUG
  pC->seekOp = OP_Rewind;
#endif
  if( isSorter(pC) ){
    rc = sqlite3VdbeSorterRewind(pC, &res);
  }else{
    assert( pC->eCurType==CURTYPE_BTREE );
    pCrsr = pC->uc.pCursor;
    assert( pCrsr );
    rc = sqlite3BtreeFirst(pCrsr, &res);
    pC->deferredMoveto = 0;
    pC->cacheStatus = CACHE_STALE;
  }
  if( rc ) goto abort_due_to_error;
  pC->nullRow = (u8)res;
  if( pOp->p2>0 ){
    VdbeBranchTaken(res!=0,2);
    if( res ) goto jump_to_p2;
  }
  break;
}

/* Opcode: IfEmpty P1 P2 * * *
** Synopsis: if( empty(P1) ) goto P2
**
** Check to see if the b-tree table that cursor P1 references is empty
** and jump to P2 if it is.
*/
case OP_IfEmpty: {        /* jump */
  VdbeCursor *pC;
  BtCursor *pCrsr;
  int res;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p2>=0 && pOp->p2<p->nOp );

  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  pCrsr = pC->uc.pCursor;
  assert( pCrsr );
  rc = sqlite3BtreeIsEmpty(pCrsr, &res);
  if( rc ) goto abort_due_to_error;
  VdbeBranchTaken(res!=0,2);
  if( res ) goto jump_to_p2;
  break;
}

/* Opcode: Next P1 P2 P3 * P5
**
** Advance cursor P1 so that it points to the next key/data pair in its
** table or index.  If there are no more key/value pairs then fall through
** to the following instruction.  But if the cursor advance was successful,
** jump immediately to P2.
**
** The Next opcode is only valid following an SeekGT, SeekGE, or
** OP_Rewind opcode used to position the cursor.  Next is not allowed
** to follow SeekLT, SeekLE, or OP_Last.
**
** The P1 cursor must be for a real table, not a pseudo-table.  P1 must have
** been opened prior to this opcode or the program will segfault.
**
** The P3 value is a hint to the btree implementation. If P3==1, that
** means P1 is an SQL index and that this instruction could have been
** omitted if that index had been unique.  P3 is usually 0.  P3 is
** always either 0 or 1.
**
** If P5 is positive and the jump is taken, then event counter
** number P5-1 in the prepared statement is incremented.
**
** See also: Prev
*/
/* Opcode: Prev P1 P2 P3 * P5
**
** Back up cursor P1 so that it points to the previous key/data pair in its
** table or index.  If there is no previous key/value pairs then fall through
** to the following instruction.  But if the cursor backup was successful,
** jump immediately to P2.
**
**
** The Prev opcode is only valid following an SeekLT, SeekLE, or
** OP_Last opcode used to position the cursor.  Prev is not allowed
** to follow SeekGT, SeekGE, or OP_Rewind.
**
** The P1 cursor must be for a real table, not a pseudo-table.  If P1 is
** not open then the behavior is undefined.
**
** The P3 value is a hint to the btree implementation. If P3==1, that
** means P1 is an SQL index and that this instruction could have been
** omitted if that index had been unique.  P3 is usually 0.  P3 is
** always either 0 or 1.
**
** If P5 is positive and the jump is taken, then event counter
** number P5-1 in the prepared statement is incremented.
*/
/* Opcode: SorterNext P1 P2 * * P5
**
** This opcode works just like OP_Next except that P1 must be a
** sorter object for which the OP_SorterSort opcode has been
** invoked.  This opcode advances the cursor to the next sorted
** record, or jumps to P2 if there are no more sorted records.
*/
case OP_SorterNext: {  /* jump */
  VdbeCursor *pC;

  pC = p->apCsr[pOp->p1];
  assert( isSorter(pC) );
  rc = sqlite3VdbeSorterNext(db, pC);
  goto next_tail;

case OP_Prev:          /* jump, ncycle */
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p5==0
       || pOp->p5==SQLITE_STMTSTATUS_FULLSCAN_STEP
       || pOp->p5==SQLITE_STMTSTATUS_AUTOINDEX);
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->deferredMoveto==0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pC->seekOp==OP_SeekLT || pC->seekOp==OP_SeekLE
       || pC->seekOp==OP_Last   || pC->seekOp==OP_IfNoHope
       || pC->seekOp==OP_NullRow);
  rc = sqlite3BtreePrevious(pC->uc.pCursor, pOp->p3);
  goto next_tail;

case OP_Next:          /* jump, ncycle */
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p5==0
       || pOp->p5==SQLITE_STMTSTATUS_FULLSCAN_STEP
       || pOp->p5==SQLITE_STMTSTATUS_AUTOINDEX);
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->deferredMoveto==0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pC->seekOp==OP_SeekGT || pC->seekOp==OP_SeekGE
       || pC->seekOp==OP_Rewind || pC->seekOp==OP_Found
       || pC->seekOp==OP_NullRow|| pC->seekOp==OP_SeekRowid
       || pC->seekOp==OP_IfNoHope);
  rc = sqlite3BtreeNext(pC->uc.pCursor, pOp->p3);

next_tail:
  pC->cacheStatus = CACHE_STALE;
  VdbeBranchTaken(rc==SQLITE_OK,2);
  if( rc==SQLITE_OK ){
    pC->nullRow = 0;
    p->aCounter[pOp->p5]++;
#ifdef SQLITE_TEST
    sqlite3_search_count++;
#endif
    goto jump_to_p2_and_check_for_interrupt;
  }
  if( rc!=SQLITE_DONE ) goto abort_due_to_error;
  rc = SQLITE_OK;
  pC->nullRow = 1;
  goto check_for_interrupt;
}

/* Opcode: IdxInsert P1 P2 P3 P4 P5
** Synopsis: key=r[P2]
**
** Register P2 holds an SQL index key made using the
** MakeRecord instructions.  This opcode writes that key
** into the index P1.  Data for the entry is nil.
**
** If P4 is not zero, then it is the number of values in the unpacked
** key of reg(P2).  In that case, P3 is the index of the first register
** for the unpacked key.  The availability of the unpacked key can sometimes
** be an optimization.
**
** If P5 has the OPFLAG_APPEND bit set, that is a hint to the b-tree layer
** that this insert is likely to be an append.
**
** If P5 has the OPFLAG_NCHANGE bit set, then the change counter is
** incremented by this instruction.  If the OPFLAG_NCHANGE bit is clear,
** then the change counter is unchanged.
**
** If the OPFLAG_USESEEKRESULT flag of P5 is set, the implementation might
** run faster by avoiding an unnecessary seek on cursor P1.  However,
** the OPFLAG_USESEEKRESULT flag must only be set if there have been no prior
** seeks on the cursor or if the most recent seek used a key equivalent
** to P2.
**
** This instruction only works for indices.  The equivalent instruction
** for tables is OP_Insert.
*/
case OP_IdxInsert: {        /* in2 */
  VdbeCursor *pC;
  BtreePayload x;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  sqlite3VdbeIncrWriteCounter(p, pC);
  assert( pC!=0 );
  assert( !isSorter(pC) );
  pIn2 = &aMem[pOp->p2];
  assert( (pIn2->flags & MEM_Blob) || (pOp->p5 & OPFLAG_PREFORMAT) );
  if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pC->isTable==0 );
  rc = ExpandBlob(pIn2);
  if( rc ) goto abort_due_to_error;
  x.nKey = pIn2->n;
  x.pKey = pIn2->z;
  x.aMem = aMem + pOp->p3;
  x.nMem = (u16)pOp->p4.i;
  rc = sqlite3BtreeInsert(pC->uc.pCursor, &x,
       (pOp->p5 & (OPFLAG_APPEND|OPFLAG_SAVEPOSITION|OPFLAG_PREFORMAT)),
      ((pOp->p5 & OPFLAG_USESEEKRESULT) ? pC->seekResult : 0)
      );
  assert( pC->deferredMoveto==0 );
  pC->cacheStatus = CACHE_STALE;
  if( rc) goto abort_due_to_error;
  break;
}

/* Opcode: SorterInsert P1 P2 * * *
** Synopsis: key=r[P2]
**
** Register P2 holds an SQL index key made using the
** MakeRecord instructions.  This opcode writes that key
** into the sorter P1.  Data for the entry is nil.
*/
case OP_SorterInsert: {     /* in2 */
  VdbeCursor *pC;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  sqlite3VdbeIncrWriteCounter(p, pC);
  assert( pC!=0 );
  assert( isSorter(pC) );
  pIn2 = &aMem[pOp->p2];
  assert( pIn2->flags & MEM_Blob );
  assert( pC->isTable==0 );
  rc = ExpandBlob(pIn2);
  if( rc ) goto abort_due_to_error;
  rc = sqlite3VdbeSorterWrite(pC, pIn2);
  if( rc) goto abort_due_to_error;
  break;
}

/* Opcode: IdxDelete P1 P2 P3 * P5
** Synopsis: key=r[P2@P3]
**
** The content of P3 registers starting at register P2 form
** an unpacked index key. This opcode removes that entry from the
** index opened by cursor P1.
**
** If P5 is not zero, then raise an SQLITE_CORRUPT_INDEX error
** if no matching index entry is found.  This happens when running
** an UPDATE or DELETE statement and the index entry to be updated
** or deleted is not found.  For some uses of IdxDelete
** (example:  the EXCEPT operator) it does not matter that no matching
** entry is found.  For those cases, P5 is zero.  Also, do not raise
** this (self-correcting and non-critical) error if in writable_schema mode.
*/
case OP_IdxDelete: {
  VdbeCursor *pC;
  BtCursor *pCrsr;
  int res;
  UnpackedRecord r;

  assert( pOp->p3>0 );
  assert( pOp->p2>0 && pOp->p2+pOp->p3<=(p->nMem+1 - p->nCursor)+1 );
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  sqlite3VdbeIncrWriteCounter(p, pC);
  pCrsr = pC->uc.pCursor;
  assert( pCrsr!=0 );
  r.pKeyInfo = pC->pKeyInfo;
  r.nField = (u16)pOp->p3;
  r.default_rc = 0;
  r.aMem = &aMem[pOp->p2];
  rc = sqlite3BtreeIndexMoveto(pCrsr, &r, &res);
  if( rc ) goto abort_due_to_error;
  if( res==0 ){
    rc = sqlite3BtreeDelete(pCrsr, BTREE_AUXDELETE);
    if( rc ) goto abort_due_to_error;
  }else if( pOp->p5 && !sqlite3WritableSchema(db) ){
    rc = sqlite3ReportError(SQLITE_CORRUPT_INDEX, __LINE__, "index corruption");
    goto abort_due_to_error;
  }
  assert( pC->deferredMoveto==0 );
  pC->cacheStatus = CACHE_STALE;
  pC->seekResult = 0;
  break;
}

/* Opcode: DeferredSeek P1 * P3 P4 *
** Synopsis: Move P3 to P1.rowid if needed
**
** P1 is an open index cursor and P3 is a cursor on the corresponding
** table.  This opcode does a deferred seek of the P3 table cursor
** to the row that corresponds to the current row of P1.
**
** This is a deferred seek.  Nothing actually happens until
** the cursor is used to read a record.  That way, if no reads
** occur, no unnecessary I/O happens.
**
** P4 may be an array of integers (type P4_INTARRAY) containing
** one entry for each column in the P3 table.  If array entry a(i)
** is non-zero, then reading column a(i)-1 from cursor P3 is
** equivalent to performing the deferred seek and then reading column i
** from P1.  This information is stored in P3 and used to redirect
** reads against P3 over to P1, thus possibly avoiding the need to
** seek and read cursor P3.
*/
/* Opcode: IdxRowid P1 P2 * * *
** Synopsis: r[P2]=rowid
**
** Write into register P2 an integer which is the last entry in the record at
** the end of the index key pointed to by cursor P1.  This integer should be
** the rowid of the table entry to which this index entry points.
**
** See also: Rowid, MakeRecord.
*/
case OP_DeferredSeek:         /* ncycle */
case OP_IdxRowid: {           /* out2, ncycle */
  VdbeCursor *pC;             /* The P1 index cursor */
  VdbeCursor *pTabCur;        /* The P2 table cursor (OP_DeferredSeek only) */
  i64 rowid;                  /* Rowid that P1 current points to */

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE || IsNullCursor(pC) );
  assert( pC->uc.pCursor!=0 );
  assert( pC->isTable==0 || IsNullCursor(pC) );
  assert( pC->deferredMoveto==0 );
  assert( !pC->nullRow || pOp->opcode==OP_IdxRowid );

  /* The IdxRowid and Seek opcodes are combined because of the commonality
  ** of sqlite3VdbeCursorRestore() and sqlite3VdbeIdxRowid(). */
  rc = sqlite3VdbeCursorRestore(pC);

  /* sqlite3VdbeCursorRestore() may fail if the cursor has been disturbed
  ** since it was last positioned and an error (e.g. OOM or an IO error)
  ** occurs while trying to reposition it. */
  if( rc!=SQLITE_OK ) goto abort_due_to_error;

  if( !pC->nullRow ){
    rowid = 0;  /* Not needed.  Only used to silence a warning. */
    rc = sqlite3VdbeIdxRowid(db, pC->uc.pCursor, &rowid);
    if( rc!=SQLITE_OK ){
      goto abort_due_to_error;
    }
    if( pOp->opcode==OP_DeferredSeek ){
      assert( pOp->p3>=0 && pOp->p3<p->nCursor );
      pTabCur = p->apCsr[pOp->p3];
      assert( pTabCur!=0 );
      assert( pTabCur->eCurType==CURTYPE_BTREE );
      assert( pTabCur->uc.pCursor!=0 );
      assert( pTabCur->isTable );
      pTabCur->nullRow = 0;
      pTabCur->movetoTarget = rowid;
      pTabCur->deferredMoveto = 1;
      pTabCur->cacheStatus = CACHE_STALE;
      assert( pOp->p4type==P4_INTARRAY || pOp->p4.ai==0 );
      assert( !pTabCur->isEphemeral );
      pTabCur->ub.aAltMap = pOp->p4.ai;
      assert( !pC->isEphemeral );
      pTabCur->pAltCursor = pC;
    }else{
      pOut = out2Prerelease(p, pOp);
      pOut->u.i = rowid;
    }
  }else{
    assert( pOp->opcode==OP_IdxRowid );
    sqlite3VdbeMemSetNull(&aMem[pOp->p2]);
  }
  break;
}

/* Opcode: FinishSeek P1 * * * *
**
** If cursor P1 was previously moved via OP_DeferredSeek, complete that
** seek operation now, without further delay.  If the cursor seek has
** already occurred, this instruction is a no-op.
*/
case OP_FinishSeek: {        /* ncycle */
  VdbeCursor *pC;            /* The P1 index cursor */

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  if( pC->deferredMoveto ){
    rc = sqlite3VdbeFinishMoveto(pC);
    if( rc ) goto abort_due_to_error;
  }
  break;
}

/* Opcode: IdxGE P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** The P4 register values beginning with P3 form an unpacked index
** key that omits the PRIMARY KEY.  Compare this key value against the index
** that P1 is currently pointing to, ignoring the PRIMARY KEY or ROWID
** fields at the end.
**
** If the P1 index entry is greater than or equal to the key value
** then jump to P2.  Otherwise fall through to the next instruction.
*/
/* Opcode: IdxGT P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** The P4 register values beginning with P3 form an unpacked index
** key that omits the PRIMARY KEY.  Compare this key value against the index
** that P1 is currently pointing to, ignoring the PRIMARY KEY or ROWID
** fields at the end.
**
** If the P1 index entry is greater than the key value
** then jump to P2.  Otherwise fall through to the next instruction.
*/
/* Opcode: IdxLT P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** The P4 register values beginning with P3 form an unpacked index
** key that omits the PRIMARY KEY or ROWID.  Compare this key value against
** the index that P1 is currently pointing to, ignoring the PRIMARY KEY or
** ROWID on the P1 index.
**
** If the P1 index entry is less than the key value then jump to P2.
** Otherwise fall through to the next instruction.
*/
/* Opcode: IdxLE P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** The P4 register values beginning with P3 form an unpacked index
** key that omits the PRIMARY KEY or ROWID.  Compare this key value against
** the index that P1 is currently pointing to, ignoring the PRIMARY KEY or
** ROWID on the P1 index.
**
** If the P1 index entry is less than or equal to the key value then jump
** to P2. Otherwise fall through to the next instruction.
*/
case OP_IdxLE:          /* jump, ncycle */
case OP_IdxGT:          /* jump, ncycle */
case OP_IdxLT:          /* jump, ncycle */
case OP_IdxGE:  {       /* jump, ncycle */
  VdbeCursor *pC;
  int res;

sqlite3.c  view on Meta::CPAN

#endif

  /* Inlined version of sqlite3VdbeIdxKeyCompare() */
  {
    i64 nCellKey = 0;
    BtCursor *pCur;
    Mem m;

    assert( pC->eCurType==CURTYPE_BTREE );
    pCur = pC->uc.pCursor;
    assert( sqlite3BtreeCursorIsValid(pCur) );
    nCellKey = sqlite3BtreePayloadSize(pCur);
    /* nCellKey will always be between 0 and 0xffffffff because of the way
    ** that btreeParseCellPtr() and sqlite3GetVarint32() are implemented */
    if( nCellKey<=0 || nCellKey>0x7fffffff ){
      rc = SQLITE_CORRUPT_BKPT;
      goto abort_due_to_error;
    }
    sqlite3VdbeMemInit(&m, db, 0);
    rc = sqlite3VdbeMemFromBtreeZeroOffset(pCur, (u32)nCellKey, &m);
    if( rc ) goto abort_due_to_error;
    res = sqlite3VdbeRecordCompareWithSkip(m.n, m.z, &r, 0);
    sqlite3VdbeMemReleaseMalloc(&m);
  }
  /* End of inlined sqlite3VdbeIdxKeyCompare() */

  assert( (OP_IdxLE&1)==(OP_IdxLT&1) && (OP_IdxGE&1)==(OP_IdxGT&1) );
  if( (pOp->opcode&1)==(OP_IdxLT&1) ){
    assert( pOp->opcode==OP_IdxLE || pOp->opcode==OP_IdxLT );
    res = -res;
  }else{
    assert( pOp->opcode==OP_IdxGE || pOp->opcode==OP_IdxGT );
    res++;
  }
  VdbeBranchTaken(res>0,2);
  assert( rc==SQLITE_OK );
  if( res>0 ) goto jump_to_p2;
  break;
}

/* Opcode: Destroy P1 P2 P3 * *
**
** Delete an entire database table or index whose root page in the database
** file is given by P1.
**
** The table being destroyed is in the main database file if P3==0.  If
** P3==1 then the table to be destroyed is in the auxiliary database file
** that is used to store tables create using CREATE TEMPORARY TABLE.
**
** If AUTOVACUUM is enabled then it is possible that another root page
** might be moved into the newly deleted root page in order to keep all
** root pages contiguous at the beginning of the database.  The former
** value of the root page that moved - its value before the move occurred -
** is stored in register P2. If no page movement was required (because the
** table being dropped was already the last one in the database) then a
** zero is stored in register P2.  If AUTOVACUUM is disabled then a zero
** is stored in register P2.
**
** This opcode throws an error if there are any active reader VMs when
** it is invoked. This is done to avoid the difficulty associated with
** updating existing cursors when a root page is moved in an AUTOVACUUM
** database. This error is thrown even if the database is not an AUTOVACUUM
** db in order to avoid introducing an incompatibility between autovacuum
** and non-autovacuum modes.
**
** See also: Clear
*/
case OP_Destroy: {     /* out2 */
  int iMoved;
  int iDb;

  sqlite3VdbeIncrWriteCounter(p, 0);
  assert( p->readOnly==0 );
  assert( pOp->p1>1 );
  pOut = out2Prerelease(p, pOp);
  pOut->flags = MEM_Null;
  if( db->nVdbeRead > db->nVDestroy+1 ){
    rc = SQLITE_LOCKED;
    p->errorAction = OE_Abort;
    goto abort_due_to_error;
  }else{
    iDb = pOp->p3;
    assert( DbMaskTest(p->btreeMask, iDb) );
    iMoved = 0;  /* Not needed.  Only to silence a warning. */
    rc = sqlite3BtreeDropTable(db->aDb[iDb].pBt, pOp->p1, &iMoved);
    pOut->flags = MEM_Int;
    pOut->u.i = iMoved;
    if( rc ) goto abort_due_to_error;
#ifndef SQLITE_OMIT_AUTOVACUUM
    if( iMoved!=0 ){
      sqlite3RootPageMoved(db, iDb, iMoved, pOp->p1);
      /* All OP_Destroy operations occur on the same btree */
      assert( resetSchemaOnFault==0 || resetSchemaOnFault==iDb+1 );
      resetSchemaOnFault = iDb+1;
    }
#endif
  }
  break;
}

/* Opcode: Clear P1 P2 P3
**
** Delete all contents of the database table or index whose root page
** in the database file is given by P1.  But, unlike Destroy, do not
** remove the table or index from the database file.
**
** The table being cleared is in the main database file if P2==0.  If
** P2==1 then the table to be cleared is in the auxiliary database file
** that is used to store tables create using CREATE TEMPORARY TABLE.
**
** If the P3 value is non-zero, then the row change count is incremented
** by the number of rows in the table being cleared. If P3 is greater
** than zero, then the value stored in register P3 is also incremented
** by the number of rows in the table being cleared.
**
** See also: Destroy
*/
case OP_Clear: {
  i64 nChange;

  sqlite3VdbeIncrWriteCounter(p, 0);
  nChange = 0;
  assert( p->readOnly==0 );
  assert( DbMaskTest(p->btreeMask, pOp->p2) );
  rc = sqlite3BtreeClearTable(db->aDb[pOp->p2].pBt, (u32)pOp->p1, &nChange);
  if( pOp->p3 ){
    p->nChange += nChange;
    if( pOp->p3>0 ){
      assert( memIsValid(&aMem[pOp->p3]) );
      memAboutToChange(p, &aMem[pOp->p3]);
      aMem[pOp->p3].u.i += nChange;
    }
  }
  if( rc ) goto abort_due_to_error;
  break;
}

/* Opcode: ResetSorter P1 * * * *
**
** Delete all contents from the ephemeral table or sorter
** that is open on cursor P1.
**
** This opcode only works for cursors used for sorting and
** opened with OP_OpenEphemeral or OP_SorterOpen.
*/
case OP_ResetSorter: {
  VdbeCursor *pC;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  if( isSorter(pC) ){
    sqlite3VdbeSorterReset(db, pC->uc.pSorter);
  }else{
    assert( pC->eCurType==CURTYPE_BTREE );
    assert( pC->isEphemeral );
    rc = sqlite3BtreeClearTableOfCursor(pC->uc.pCursor);
    if( rc ) goto abort_due_to_error;
  }
  break;
}

/* Opcode: CreateBtree P1 P2 P3 * *
** Synopsis: r[P2]=root iDb=P1 flags=P3
**
** Allocate a new b-tree in the main database file if P1==0 or in the
** TEMP database file if P1==1 or in an attached database if
** P1>1.  The P3 argument must be 1 (BTREE_INTKEY) for a rowid table
** it must be 2 (BTREE_BLOBKEY) for an index or WITHOUT ROWID table.
** The root page number of the new b-tree is stored in register P2.
*/
case OP_CreateBtree: {          /* out2 */
  Pgno pgno;
  Db *pDb;

  sqlite3VdbeIncrWriteCounter(p, 0);
  pOut = out2Prerelease(p, pOp);
  pgno = 0;
  assert( pOp->p3==BTREE_INTKEY || pOp->p3==BTREE_BLOBKEY );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( DbMaskTest(p->btreeMask, pOp->p1) );
  assert( p->readOnly==0 );
  pDb = &db->aDb[pOp->p1];
  assert( pDb->pBt!=0 );
  rc = sqlite3BtreeCreateTable(pDb->pBt, &pgno, pOp->p3);
  if( rc ) goto abort_due_to_error;
  pOut->u.i = pgno;
  break;
}

/* Opcode: SqlExec P1 P2 * P4 *
**
** Run the SQL statement or statements specified in the P4 string.
**
** The P1 parameter is a bitmask of options:
**
**    0x0001     Disable Auth and Trace callbacks while the statements
**               in P4 are running.
**
**    0x0002     Set db->nAnalysisLimit to P2 while the statements in
**               P4 are running.
**
*/

sqlite3.c  view on Meta::CPAN

**
** Execute the trigger program passed as P4 (type P4_SUBPROGRAM).
**
** P1 contains the address of the memory cell that contains the first memory
** cell in an array of values used as arguments to the sub-program. P2
** contains the address to jump to if the sub-program throws an IGNORE
** exception using the RAISE() function. P2 might be zero, if there is
** no possibility that an IGNORE exception will be raised.
** Register P3 contains the address
** of a memory cell in this (the parent) VM that is used to allocate the
** memory required by the sub-vdbe at runtime.
**
** P4 is a pointer to the VM containing the trigger program.
**
** If P5 is non-zero, then recursive program invocation is enabled.
*/
case OP_Program: {        /* jump0 */
  int nMem;               /* Number of memory registers for sub-program */
  i64 nByte;              /* Bytes of runtime space required for sub-program */
  Mem *pRt;               /* Register to allocate runtime space */
  Mem *pMem;              /* Used to iterate through memory cells */
  Mem *pEnd;              /* Last memory cell in new array */
  VdbeFrame *pFrame;      /* New vdbe frame to execute in */
  SubProgram *pProgram;   /* Sub-program to execute */
  void *t;                /* Token identifying trigger */

  pProgram = pOp->p4.pProgram;
  pRt = &aMem[pOp->p3];
  assert( pProgram->nOp>0 );

  /* If the p5 flag is clear, then recursive invocation of triggers is
  ** disabled for backwards compatibility (p5 is set if this sub-program
  ** is really a trigger, not a foreign key action, and the flag set
  ** and cleared by the "PRAGMA recursive_triggers" command is clear).
  **
  ** It is recursive invocation of triggers, at the SQL level, that is
  ** disabled. In some cases a single trigger may generate more than one
  ** SubProgram (if the trigger may be executed with more than one different
  ** ON CONFLICT algorithm). SubProgram structures associated with a
  ** single trigger all have the same value for the SubProgram.token
  ** variable.  */
  if( pOp->p5 ){
    t = pProgram->token;
    for(pFrame=p->pFrame; pFrame && pFrame->token!=t; pFrame=pFrame->pParent);
    if( pFrame ) break;
  }

  if( p->nFrame>=db->aLimit[SQLITE_LIMIT_TRIGGER_DEPTH] ){
    rc = SQLITE_ERROR;
    sqlite3VdbeError(p, "too many levels of trigger recursion");
    goto abort_due_to_error;
  }

  /* Register pRt is used to store the memory required to save the state
  ** of the current program, and the memory required at runtime to execute
  ** the trigger program. If this trigger has been fired before, then pRt
  ** is already allocated. Otherwise, it must be initialized.  */
  if( (pRt->flags&MEM_Blob)==0 ){
    /* SubProgram.nMem is set to the number of memory cells used by the
    ** program stored in SubProgram.aOp. As well as these, one memory
    ** cell is required for each cursor used by the program. Set local
    ** variable nMem (and later, VdbeFrame.nChildMem) to this value.
    */
    nMem = pProgram->nMem + pProgram->nCsr;
    assert( nMem>0 );
    if( pProgram->nCsr==0 ) nMem++;
    nByte = ROUND8(sizeof(VdbeFrame))
              + nMem * sizeof(Mem)
              + pProgram->nCsr * sizeof(VdbeCursor*)
              + (7 + (i64)pProgram->nOp)/8;
    pFrame = sqlite3DbMallocZero(db, nByte);
    if( !pFrame ){
      goto no_mem;
    }
    sqlite3VdbeMemRelease(pRt);
    pRt->flags = MEM_Blob|MEM_Dyn;
    pRt->z = (char*)pFrame;
    pRt->n = (int)nByte;
    pRt->xDel = sqlite3VdbeFrameMemDel;

    pFrame->v = p;
    pFrame->nChildMem = nMem;
    pFrame->nChildCsr = pProgram->nCsr;
    pFrame->pc = (int)(pOp - aOp);
    pFrame->aMem = p->aMem;
    pFrame->nMem = p->nMem;
    pFrame->apCsr = p->apCsr;
    pFrame->nCursor = p->nCursor;
    pFrame->aOp = p->aOp;
    pFrame->nOp = p->nOp;
    pFrame->token = pProgram->token;
#ifdef SQLITE_DEBUG
    pFrame->iFrameMagic = SQLITE_FRAME_MAGIC;
#endif

    pEnd = &VdbeFrameMem(pFrame)[pFrame->nChildMem];
    for(pMem=VdbeFrameMem(pFrame); pMem!=pEnd; pMem++){
      pMem->flags = MEM_Undefined;
      pMem->db = db;
    }
  }else{
    pFrame = (VdbeFrame*)pRt->z;
    assert( pRt->xDel==sqlite3VdbeFrameMemDel );
    assert( pProgram->nMem+pProgram->nCsr==pFrame->nChildMem
        || (pProgram->nCsr==0 && pProgram->nMem+1==pFrame->nChildMem) );
    assert( pProgram->nCsr==pFrame->nChildCsr );
    assert( (int)(pOp - aOp)==pFrame->pc );
  }

  p->nFrame++;
  pFrame->pParent = p->pFrame;
  pFrame->lastRowid = db->lastRowid;
  pFrame->nChange = p->nChange;
  pFrame->nDbChange = p->db->nChange;
  assert( pFrame->pAuxData==0 );
  pFrame->pAuxData = p->pAuxData;
  p->pAuxData = 0;
  p->nChange = 0;
  p->pFrame = pFrame;
  p->aMem = aMem = VdbeFrameMem(pFrame);
  p->nMem = pFrame->nChildMem;

sqlite3.c  view on Meta::CPAN

  rc = sqlite3RunVacuum(&p->zErrMsg, db, pOp->p1,
                        pOp->p2 ? &aMem[pOp->p2] : 0);
  if( rc ) goto abort_due_to_error;
  break;
}
#endif

#if !defined(SQLITE_OMIT_AUTOVACUUM)
/* Opcode: IncrVacuum P1 P2 * * *
**
** Perform a single step of the incremental vacuum procedure on
** the P1 database. If the vacuum has finished, jump to instruction
** P2. Otherwise, fall through to the next instruction.
*/
case OP_IncrVacuum: {        /* jump */
  Btree *pBt;

  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( DbMaskTest(p->btreeMask, pOp->p1) );
  assert( p->readOnly==0 );
  pBt = db->aDb[pOp->p1].pBt;
  rc = sqlite3BtreeIncrVacuum(pBt);
  VdbeBranchTaken(rc==SQLITE_DONE,2);
  if( rc ){
    if( rc!=SQLITE_DONE ) goto abort_due_to_error;
    rc = SQLITE_OK;
    goto jump_to_p2;
  }
  break;
}
#endif

/* Opcode: Expire P1 P2 * * *
**
** Cause precompiled statements to expire.  When an expired statement
** is executed using sqlite3_step() it will either automatically
** reprepare itself (if it was originally created using sqlite3_prepare_v2())
** or it will fail with SQLITE_SCHEMA.
**
** If P1 is 0, then all SQL statements become expired. If P1 is non-zero,
** then only the currently executing statement is expired.
**
** If P2 is 0, then SQL statements are expired immediately.  If P2 is 1,
** then running SQL statements are allowed to continue to run to completion.
** The P2==1 case occurs when a CREATE INDEX or similar schema change happens
** that might help the statement run faster but which does not affect the
** correctness of operation.
*/
case OP_Expire: {
  assert( pOp->p2==0 || pOp->p2==1 );
  if( !pOp->p1 ){
    sqlite3ExpirePreparedStatements(db, pOp->p2);
  }else{
    p->expired = pOp->p2+1;
  }
  break;
}

/* Opcode: CursorLock P1 * * * *
**
** Lock the btree to which cursor P1 is pointing so that the btree cannot be
** written by an other cursor.
*/
case OP_CursorLock: {
  VdbeCursor *pC;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  sqlite3BtreeCursorPin(pC->uc.pCursor);
  break;
}

/* Opcode: CursorUnlock P1 * * * *
**
** Unlock the btree to which cursor P1 is pointing so that it can be
** written by other cursors.
*/
case OP_CursorUnlock: {
  VdbeCursor *pC;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->eCurType==CURTYPE_BTREE );
  sqlite3BtreeCursorUnpin(pC->uc.pCursor);
  break;
}

#ifndef SQLITE_OMIT_SHARED_CACHE
/* Opcode: TableLock P1 P2 P3 P4 *
** Synopsis: iDb=P1 root=P2 write=P3
**
** Obtain a lock on a particular table. This instruction is only used when
** the shared-cache feature is enabled.
**
** P1 is the index of the database in sqlite3.aDb[] of the database
** on which the lock is acquired.  A readlock is obtained if P3==0 or
** a write lock if P3==1.
**
** P2 contains the root-page of the table to lock.
**
** P4 contains a pointer to the name of the table being locked. This is only
** used to generate an error message if the lock cannot be obtained.
*/
case OP_TableLock: {
  u8 isWriteLock = (u8)pOp->p3;
  if( isWriteLock || 0==(db->flags&SQLITE_ReadUncommit) ){
    int p1 = pOp->p1;
    assert( p1>=0 && p1<db->nDb );
    assert( DbMaskTest(p->btreeMask, p1) );
    assert( isWriteLock==0 || isWriteLock==1 );
    rc = sqlite3BtreeLockTable(db->aDb[p1].pBt, pOp->p2, isWriteLock);
    if( rc ){
      if( (rc&0xFF)==SQLITE_LOCKED ){
        const char *z = pOp->p4.z;
        sqlite3VdbeError(p, "database table is locked: %s", z);
      }
      goto abort_due_to_error;
    }
  }
  break;
}
#endif /* SQLITE_OMIT_SHARED_CACHE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VBegin * * * P4 *
**
** P4 may be a pointer to an sqlite3_vtab structure. If so, call the
** xBegin method for that table.
**
** Also, whether or not P4 is set, check that this is not being called from
** within a callback to a virtual table xSync() method. If it is, the error
** code will be set to SQLITE_LOCKED.
*/
case OP_VBegin: {
  VTable *pVTab;
  pVTab = pOp->p4.pVtab;
  rc = sqlite3VtabBegin(db, pVTab);
  if( pVTab ) sqlite3VtabImportErrmsg(p, pVTab->pVtab);
  if( rc ) goto abort_due_to_error;
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VCreate P1 P2 * * *
**
** P2 is a register that holds the name of a virtual table in database
** P1. Call the xCreate method for that table.
*/
case OP_VCreate: {
  Mem sMem;          /* For storing the record being decoded */
  const char *zTab;  /* Name of the virtual table */

  memset(&sMem, 0, sizeof(sMem));
  sMem.db = db;
  /* Because P2 is always a static string, it is impossible for the
  ** sqlite3VdbeMemCopy() to fail */
  assert( (aMem[pOp->p2].flags & MEM_Str)!=0 );
  assert( (aMem[pOp->p2].flags & MEM_Static)!=0 );
  rc = sqlite3VdbeMemCopy(&sMem, &aMem[pOp->p2]);
  assert( rc==SQLITE_OK );
  zTab = (const char*)sqlite3_value_text(&sMem);
  assert( zTab || db->mallocFailed );
  if( zTab ){
    rc = sqlite3VtabCallCreate(db, pOp->p1, zTab, &p->zErrMsg);
  }
  sqlite3VdbeMemRelease(&sMem);
  if( rc ) goto abort_due_to_error;
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VDestroy P1 * * P4 *
**
** P4 is the name of a virtual table in database P1.  Call the xDestroy method
** of that table.
*/
case OP_VDestroy: {
  db->nVDestroy++;
  rc = sqlite3VtabCallDestroy(db, pOp->p1, pOp->p4.z);
  db->nVDestroy--;
  assert( p->errorAction==OE_Abort && p->usesStmtJournal );
  if( rc ) goto abort_due_to_error;
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VOpen P1 * * P4 *
**
** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
** P1 is a cursor number.  This opcode opens a cursor to the virtual
** table and stores that cursor in P1.
*/
case OP_VOpen: {             /* ncycle */
  VdbeCursor *pCur;
  sqlite3_vtab_cursor *pVCur;
  sqlite3_vtab *pVtab;
  const sqlite3_module *pModule;

  assert( p->bIsReader );
  pCur = p->apCsr[pOp->p1];
  if( pCur!=0
   && ALWAYS( pCur->eCurType==CURTYPE_VTAB )
   && ALWAYS( pCur->uc.pVCur->pVtab==pOp->p4.pVtab->pVtab )
  ){
    /* This opcode is a no-op if the cursor is already open */
    break;
  }
  pVCur = 0;
  pVtab = pOp->p4.pVtab->pVtab;
  if( pVtab==0 || NEVER(pVtab->pModule==0) ){
    rc = SQLITE_LOCKED;
    goto abort_due_to_error;
  }
  pModule = pVtab->pModule;
  rc = pModule->xOpen(pVtab, &pVCur);
  sqlite3VtabImportErrmsg(p, pVtab);
  if( rc ) goto abort_due_to_error;

  /* Initialize sqlite3_vtab_cursor base class */
  pVCur->pVtab = pVtab;

  /* Initialize vdbe cursor object */
  pCur = allocateCursor(p, pOp->p1, 0, CURTYPE_VTAB);
  if( pCur ){
    pCur->uc.pVCur = pVCur;
    pVtab->nRef++;
  }else{
    assert( db->mallocFailed );
    pModule->xClose(pVCur);
    goto no_mem;
  }
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VCheck P1 P2 P3 P4 *
**
** P4 is a pointer to a Table object that is a virtual table in schema P1
** that supports the xIntegrity() method.  This opcode runs the xIntegrity()
** method for that virtual table, using P3 as the integer argument.  If
** an error is reported back, the table name is prepended to the error
** message and that message is stored in P2.  If no errors are seen,
** register P2 is set to NULL.
*/
case OP_VCheck: {             /* out2 */
  Table *pTab;
  sqlite3_vtab *pVtab;
  const sqlite3_module *pModule;
  char *zErr = 0;

  pOut = &aMem[pOp->p2];
  sqlite3VdbeMemSetNull(pOut);  /* Innocent until proven guilty */
  assert( pOp->p4type==P4_TABLEREF );
  pTab = pOp->p4.pTab;
  assert( pTab!=0 );
  assert( pTab->nTabRef>0 );
  assert( IsVirtual(pTab) );
  if( pTab->u.vtab.p==0 ) break;
  pVtab = pTab->u.vtab.p->pVtab;
  assert( pVtab!=0 );
  pModule = pVtab->pModule;
  assert( pModule!=0 );
  assert( pModule->iVersion>=4 );
  assert( pModule->xIntegrity!=0 );
  sqlite3VtabLock(pTab->u.vtab.p);
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  rc = pModule->xIntegrity(pVtab, db->aDb[pOp->p1].zDbSName, pTab->zName,
                           pOp->p3, &zErr);
  sqlite3VtabUnlock(pTab->u.vtab.p);
  if( rc ){
    sqlite3_free(zErr);
    goto abort_due_to_error;
  }
  if( zErr ){
    sqlite3VdbeMemSetStr(pOut, zErr, -1, SQLITE_UTF8, sqlite3_free);
  }
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VInitIn P1 P2 P3 * *
** Synopsis: r[P2]=ValueList(P1,P3)
**
** Set register P2 to be a pointer to a ValueList object for cursor P1
** with cache register P3 and output register P3+1.  This ValueList object
** can be used as the first argument to sqlite3_vtab_in_first() and
** sqlite3_vtab_in_next() to extract all of the values stored in the P1
** cursor.  Register P3 is used to hold the values returned by
** sqlite3_vtab_in_first() and sqlite3_vtab_in_next().
*/
case OP_VInitIn: {        /* out2, ncycle */
  VdbeCursor *pC;         /* The cursor containing the RHS values */
  ValueList *pRhs;        /* New ValueList object to put in reg[P2] */

  pC = p->apCsr[pOp->p1];
  pRhs = sqlite3_malloc64( sizeof(*pRhs) );
  if( pRhs==0 ) goto no_mem;
  pRhs->pCsr = pC->uc.pCursor;
  pRhs->pOut = &aMem[pOp->p3];
  pOut = out2Prerelease(p, pOp);
  pOut->flags = MEM_Null;
  sqlite3VdbeMemSetPointer(pOut, pRhs, "ValueList", sqlite3VdbeValueListFree);
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */


#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VFilter P1 P2 P3 P4 *
** Synopsis: iplan=r[P3] zplan='P4'
**
** P1 is a cursor opened using VOpen.  P2 is an address to jump to if
** the filtered result set is empty.
**
** P4 is either NULL or a string that was generated by the xBestIndex
** method of the module.  The interpretation of the P4 string is left
** to the module implementation.
**
** This opcode invokes the xFilter method on the virtual table specified
** by P1.  The integer query plan parameter to xFilter is stored in register
** P3. Register P3+1 stores the argc parameter to be passed to the
** xFilter method. Registers P3+2..P3+1+argc are the argc
** additional parameters which are passed to
** xFilter as argv. Register P3+2 becomes argv[0] when passed to xFilter.
**
** A jump is made to P2 if the result set after filtering would be empty.
*/
case OP_VFilter: {   /* jump, ncycle */
  int nArg;
  int iQuery;
  const sqlite3_module *pModule;
  Mem *pQuery;
  Mem *pArgc;
  sqlite3_vtab_cursor *pVCur;
  sqlite3_vtab *pVtab;
  VdbeCursor *pCur;
  int res;
  int i;
  Mem **apArg;

  pQuery = &aMem[pOp->p3];
  pArgc = &pQuery[1];
  pCur = p->apCsr[pOp->p1];
  assert( memIsValid(pQuery) );
  REGISTER_TRACE(pOp->p3, pQuery);
  assert( pCur!=0 );
  assert( pCur->eCurType==CURTYPE_VTAB );
  pVCur = pCur->uc.pVCur;
  pVtab = pVCur->pVtab;
  pModule = pVtab->pModule;

  /* Grab the index number and argc parameters */
  assert( (pQuery->flags&MEM_Int)!=0 && pArgc->flags==MEM_Int );
  nArg = (int)pArgc->u.i;
  iQuery = (int)pQuery->u.i;

  /* Invoke the xFilter method */
  apArg = p->apArg;
  assert( nArg<=p->napArg );
  for(i = 0; i<nArg; i++){
    apArg[i] = &pArgc[i+1];
  }
  rc = pModule->xFilter(pVCur, iQuery, pOp->p4.z, nArg, apArg);
  sqlite3VtabImportErrmsg(p, pVtab);
  if( rc ) goto abort_due_to_error;
  res = pModule->xEof(pVCur);
  pCur->nullRow = 0;
  VdbeBranchTaken(res!=0,2);
  if( res ) goto jump_to_p2;
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VColumn P1 P2 P3 * P5
** Synopsis: r[P3]=vcolumn(P2)
**
** Store in register P3 the value of the P2-th column of
** the current row of the virtual-table of cursor P1.
**
** If the VColumn opcode is being used to fetch the value of
** an unchanging column during an UPDATE operation, then the P5
** value is OPFLAG_NOCHNG.  This will cause the sqlite3_vtab_nochange()
** function to return true inside the xColumn method of the virtual
** table implementation.  The P5 column might also contain other
** bits (OPFLAG_LENGTHARG or OPFLAG_TYPEOFARG) but those bits are
** unused by OP_VColumn.
*/
case OP_VColumn: {           /* ncycle */
  sqlite3_vtab *pVtab;
  const sqlite3_module *pModule;
  Mem *pDest;
  sqlite3_context sContext;
  FuncDef nullFunc;

  VdbeCursor *pCur = p->apCsr[pOp->p1];
  assert( pCur!=0 );
  assert( pOp->p3>0 && pOp->p3<=(p->nMem+1 - p->nCursor) );
  pDest = &aMem[pOp->p3];
  memAboutToChange(p, pDest);
  if( pCur->nullRow ){
    sqlite3VdbeMemSetNull(pDest);
    break;
  }
  assert( pCur->eCurType==CURTYPE_VTAB );
  pVtab = pCur->uc.pVCur->pVtab;
  pModule = pVtab->pModule;
  assert( pModule->xColumn );
  memset(&sContext, 0, sizeof(sContext));
  sContext.pOut = pDest;
  sContext.enc = encoding;
  nullFunc.pUserData = 0;
  nullFunc.funcFlags = SQLITE_RESULT_SUBTYPE;
  sContext.pFunc = &nullFunc;
  assert( pOp->p5==OPFLAG_NOCHNG || pOp->p5==0 );
  if( pOp->p5 & OPFLAG_NOCHNG ){
    sqlite3VdbeMemSetNull(pDest);
    pDest->flags = MEM_Null|MEM_Zero;
    pDest->u.nZero = 0;
  }else{
    MemSetTypeFlag(pDest, MEM_Null);
  }
  rc = pModule->xColumn(pCur->uc.pVCur, &sContext, pOp->p2);
  sqlite3VtabImportErrmsg(p, pVtab);
  if( sContext.isError>0 ){
    sqlite3VdbeError(p, "%s", sqlite3_value_text(pDest));
    rc = sContext.isError;
  }
  sqlite3VdbeChangeEncoding(pDest, encoding);
  REGISTER_TRACE(pOp->p3, pDest);
  UPDATE_MAX_BLOBSIZE(pDest);

  if( rc ) goto abort_due_to_error;
  break;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VNext P1 P2 * * *
**
** Advance virtual table P1 to the next row in its result set and
** jump to instruction P2.  Or, if the virtual table has reached
** the end of its result set, then fall through to the next instruction.
*/
case OP_VNext: {   /* jump, ncycle */
  sqlite3_vtab *pVtab;
  const sqlite3_module *pModule;
  int res;
  VdbeCursor *pCur;

  pCur = p->apCsr[pOp->p1];
  assert( pCur!=0 );
  assert( pCur->eCurType==CURTYPE_VTAB );
  if( pCur->nullRow ){
    break;
  }
  pVtab = pCur->uc.pVCur->pVtab;
  pModule = pVtab->pModule;
  assert( pModule->xNext );

  /* Invoke the xNext() method of the module. There is no way for the
  ** underlying implementation to return an error if one occurs during
  ** xNext(). Instead, if an error occurs, true is returned (indicating that
  ** data is available) and the error code returned when xColumn or
  ** some other method is next invoked on the save virtual table cursor.
  */
  rc = pModule->xNext(pCur->uc.pVCur);
  sqlite3VtabImportErrmsg(p, pVtab);
  if( rc ) goto abort_due_to_error;
  res = pModule->xEof(pCur->uc.pVCur);
  VdbeBranchTaken(!res,2);
  if( !res ){
    /* If there is data, jump to P2 */
    goto jump_to_p2_and_check_for_interrupt;
  }
  goto check_for_interrupt;
}
#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VRename P1 * * P4 *
**
** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
** This opcode invokes the corresponding xRename method. The value
** in register P1 is passed as the zName argument to the xRename method.
*/
case OP_VRename: {
  sqlite3_vtab *pVtab;
  Mem *pName;
  int isLegacy;

  isLegacy = (db->flags & SQLITE_LegacyAlter);
  db->flags |= SQLITE_LegacyAlter;
  pVtab = pOp->p4.pVtab->pVtab;
  pName = &aMem[pOp->p1];
  assert( pVtab->pModule->xRename );
  assert( memIsValid(pName) );
  assert( p->readOnly==0 );
  REGISTER_TRACE(pOp->p1, pName);
  assert( pName->flags & MEM_Str );
  testcase( pName->enc==SQLITE_UTF8 );
  testcase( pName->enc==SQLITE_UTF16BE );
  testcase( pName->enc==SQLITE_UTF16LE );
  rc = sqlite3VdbeChangeEncoding(pName, SQLITE_UTF8);
  if( rc ) goto abort_due_to_error;
  rc = pVtab->pModule->xRename(pVtab, pName->z);
  if( isLegacy==0 ) db->flags &= ~(u64)SQLITE_LegacyAlter;
  sqlite3VtabImportErrmsg(p, pVtab);
  p->expired = 0;
  if( rc ) goto abort_due_to_error;
  break;
}
#endif

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Opcode: VUpdate P1 P2 P3 P4 P5
** Synopsis: data=r[P3@P2]
**
** P4 is a pointer to a virtual table object, an sqlite3_vtab structure.
** This opcode invokes the corresponding xUpdate method. P2 values
** are contiguous memory cells starting at P3 to pass to the xUpdate
** invocation. The value in register (P3+P2-1) corresponds to the
** p2th element of the argv array passed to xUpdate.
**
** The xUpdate method will do a DELETE or an INSERT or both.

sqlite3.c  view on Meta::CPAN

  */
  assert( pOp->p4.z==0 || strncmp(pOp->p4.z, "-" "- ", 3)==0 );

  /* OP_Init is always instruction 0 */
  assert( pOp==p->aOp || pOp->opcode==OP_Trace );

#ifndef SQLITE_OMIT_TRACE
  if( (db->mTrace & (SQLITE_TRACE_STMT|SQLITE_TRACE_LEGACY))!=0
   && p->minWriteFileFormat!=254  /* tag-20220401a */
   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
  ){
#ifndef SQLITE_OMIT_DEPRECATED
    if( db->mTrace & SQLITE_TRACE_LEGACY ){
      char *z = sqlite3VdbeExpandSql(p, zTrace);
      db->trace.xLegacy(db->pTraceArg, z);
      sqlite3_free(z);
    }else
#endif
    if( db->nVdbeExec>1 ){
      char *z = sqlite3MPrintf(db, "-- %s", zTrace);
      (void)db->trace.xV2(SQLITE_TRACE_STMT, db->pTraceArg, p, z);
      sqlite3DbFree(db, z);
    }else{
      (void)db->trace.xV2(SQLITE_TRACE_STMT, db->pTraceArg, p, zTrace);
    }
  }
#ifdef SQLITE_USE_FCNTL_TRACE
  zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql);
  if( zTrace ){
    int j;
    for(j=0; j<db->nDb; j++){
      if( DbMaskTest(p->btreeMask, j)==0 ) continue;
      sqlite3_file_control(db, db->aDb[j].zDbSName, SQLITE_FCNTL_TRACE, zTrace);
    }
  }
#endif /* SQLITE_USE_FCNTL_TRACE */
#ifdef SQLITE_DEBUG
  if( (db->flags & SQLITE_SqlTrace)!=0
   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
  ){
    sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);
  }
#endif /* SQLITE_DEBUG */
#endif /* SQLITE_OMIT_TRACE */
  assert( pOp->p2>0 );
  if( pOp->p1>=sqlite3GlobalConfig.iOnceResetThreshold ){
    if( pOp->opcode==OP_Trace ) break;
    for(i=1; i<p->nOp; i++){
      if( p->aOp[i].opcode==OP_Once ) p->aOp[i].p1 = 0;
    }
    pOp->p1 = 0;
  }
  pOp->p1++;
  p->aCounter[SQLITE_STMTSTATUS_RUN]++;
  goto jump_to_p2;
}

#ifdef SQLITE_ENABLE_CURSOR_HINTS
/* Opcode: CursorHint P1 * * P4 *
**
** Provide a hint to cursor P1 that it only needs to return rows that
** satisfy the Expr in P4.  TK_REGISTER terms in the P4 expression refer
** to values currently held in registers.  TK_COLUMN terms in the P4
** expression refer to columns in the b-tree to which cursor P1 is pointing.
*/
case OP_CursorHint: {
  VdbeCursor *pC;

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p4type==P4_EXPR );
  pC = p->apCsr[pOp->p1];
  if( pC ){
    assert( pC->eCurType==CURTYPE_BTREE );
    sqlite3BtreeCursorHint(pC->uc.pCursor, BTREE_HINT_RANGE,
                           pOp->p4.pExpr, aMem);
  }
  break;
}
#endif /* SQLITE_ENABLE_CURSOR_HINTS */

#ifdef SQLITE_DEBUG
/* Opcode:  Abortable   * * * * *
**
** Verify that an Abort can happen.  Assert if an Abort at this point
** might cause database corruption.  This opcode only appears in debugging
** builds.
**
** An Abort is safe if either there have been no writes, or if there is
** an active statement journal.
*/
case OP_Abortable: {
  sqlite3VdbeAssertAbortable(p);
  break;
}
#endif

#ifdef SQLITE_DEBUG
/* Opcode:  ReleaseReg   P1 P2 P3 * P5
** Synopsis: release r[P1@P2] mask P3
**
** Release registers from service.  Any content that was in the
** the registers is unreliable after this opcode completes.
**
** The registers released will be the P2 registers starting at P1,
** except if bit ii of P3 set, then do not release register P1+ii.
** In other words, P3 is a mask of registers to preserve.
**
** Releasing a register clears the Mem.pScopyFrom pointer.  That means
** that if the content of the released register was set using OP_SCopy,
** a change to the value of the source register for the OP_SCopy will no longer
** generate an assertion fault in sqlite3VdbeMemAboutToChange().
**
** If P5 is set, then all released registers have their type set
** to MEM_Undefined so that any subsequent attempt to read the released
** register (before it is reinitialized) will generate an assertion fault.
**
** P5 ought to be set on every call to this opcode.
** However, there are places in the code generator will release registers
** before their are used, under the (valid) assumption that the registers
** will not be reallocated for some other purpose before they are used and
** hence are safe to release.
**
** This opcode is only available in testing and debugging builds.  It is
** not generated for release builds.  The purpose of this opcode is to help

sqlite3.c  view on Meta::CPAN

  }
  assert( rc!=SQLITE_OK || nExtraDelete==0
       || sqlite3_strlike("DELETE%",p->zSql,0)!=0
  );
  return rc;

  /* Jump to here if a string or blob larger than SQLITE_MAX_LENGTH
  ** is encountered.
  */
too_big:
  sqlite3VdbeError(p, "string or blob too big");
  rc = SQLITE_TOOBIG;
  goto abort_due_to_error;

  /* Jump to here if a malloc() fails.
  */
no_mem:
  sqlite3OomFault(db);
  sqlite3VdbeError(p, "out of memory");
  rc = SQLITE_NOMEM_BKPT;
  goto abort_due_to_error;

  /* Jump to here if the sqlite3_interrupt() API sets the interrupt
  ** flag.
  */
abort_due_to_interrupt:
  assert( AtomicLoad(&db->u1.isInterrupted) );
  rc = SQLITE_INTERRUPT;
  goto abort_due_to_error;
}


/************** End of vdbe.c ************************************************/
/************** Begin file vdbeblob.c ****************************************/
/*
** 2007 May 1
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains code used to implement incremental BLOB I/O.
*/

/* #include "sqliteInt.h" */
/* #include "vdbeInt.h" */

#ifndef SQLITE_OMIT_INCRBLOB

/*
** Valid sqlite3_blob* handles point to Incrblob structures.
*/
typedef struct Incrblob Incrblob;
struct Incrblob {
  int nByte;              /* Size of open blob, in bytes */
  int iOffset;            /* Byte offset of blob in cursor data */
  u16 iCol;               /* Table column this handle is open on */
  BtCursor *pCsr;         /* Cursor pointing at blob row */
  sqlite3_stmt *pStmt;    /* Statement holding cursor open */
  sqlite3 *db;            /* The associated database */
  char *zDb;              /* Database name */
  Table *pTab;            /* Table object */
};


/*
** This function is used by both blob_open() and blob_reopen(). It seeks
** the b-tree cursor associated with blob handle p to point to row iRow.
** If successful, SQLITE_OK is returned and subsequent calls to
** sqlite3_blob_read() or sqlite3_blob_write() access the specified row.
**
** If an error occurs, or if the specified row does not exist or does not
** contain a value of type TEXT or BLOB in the column nominated when the
** blob handle was opened, then an error code is returned and *pzErr may
** be set to point to a buffer containing an error message. It is the
** responsibility of the caller to free the error message buffer using
** sqlite3DbFree().
**
** If an error does occur, then the b-tree cursor is closed. All subsequent
** calls to sqlite3_blob_read(), blob_write() or blob_reopen() will
** immediately return SQLITE_ABORT.
*/
static int blobSeekToRow(Incrblob *p, sqlite3_int64 iRow, char **pzErr){
  int rc;                         /* Error code */
  char *zErr = 0;                 /* Error message */
  Vdbe *v = (Vdbe *)p->pStmt;

  /* Set the value of register r[1] in the SQL statement to integer iRow.
  ** This is done directly as a performance optimization
  */
  sqlite3VdbeMemSetInt64(&v->aMem[1], iRow);

  /* If the statement has been run before (and is paused at the OP_ResultRow)
  ** then back it up to the point where it does the OP_NotExists.  This could
  ** have been down with an extra OP_Goto, but simply setting the program
  ** counter is faster. */
  if( v->pc>4 ){
    v->pc = 4;
    assert( v->aOp[v->pc].opcode==OP_NotExists );
    rc = sqlite3VdbeExec(v);
  }else{
    rc = sqlite3_step(p->pStmt);
  }
  if( rc==SQLITE_ROW ){
    VdbeCursor *pC = v->apCsr[0];
    u32 type;
    assert( pC!=0 );
    assert( pC->eCurType==CURTYPE_BTREE );
    type = pC->nHdrParsed>p->iCol ? pC->aType[p->iCol] : 0;
    testcase( pC->nHdrParsed==p->iCol );
    testcase( pC->nHdrParsed==p->iCol+1 );
    if( type<12 ){
      zErr = sqlite3MPrintf(p->db, "cannot open value of type %s",
          type==0?"null": type==7?"real": "integer"
      );
      rc = SQLITE_ERROR;
      sqlite3_finalize(p->pStmt);
      p->pStmt = 0;
    }else{
      p->iOffset = pC->aType[p->iCol + pC->nField];
      p->nByte = sqlite3VdbeSerialTypeLen(type);
      p->pCsr =  pC->uc.pCursor;
      sqlite3BtreeIncrblobCursor(p->pCsr);
    }
  }

  if( rc==SQLITE_ROW ){
    rc = SQLITE_OK;
  }else if( p->pStmt ){
    rc = sqlite3_finalize(p->pStmt);
    p->pStmt = 0;
    if( rc==SQLITE_OK ){
      zErr = sqlite3MPrintf(p->db, "no such rowid: %lld", iRow);
      rc = SQLITE_ERROR;
    }else{
      zErr = sqlite3MPrintf(p->db, "%s", sqlite3_errmsg(p->db));
    }
  }

sqlite3.c  view on Meta::CPAN

    }
    pBlob->pTab = pTab;
    pBlob->zDb = db->aDb[iDb].zDbSName;

    /* Now search pTab for the exact column. */
    iCol = sqlite3ColumnIndex(pTab, zColumn);
    if( iCol<0 ){
      sqlite3DbFree(db, zErr);
      zErr = sqlite3MPrintf(db, "no such column: \"%s\"", zColumn);
      rc = SQLITE_ERROR;
      sqlite3BtreeLeaveAll(db);
      goto blob_open_out;
    }

    /* If the value is being opened for writing, check that the
    ** column is not indexed, and that it is not part of a foreign key.
    */
    if( wrFlag ){
      const char *zFault = 0;
      Index *pIdx;
#ifndef SQLITE_OMIT_FOREIGN_KEY
      if( db->flags&SQLITE_ForeignKeys ){
        /* Check that the column is not part of an FK child key definition. It
        ** is not necessary to check if it is part of a parent key, as parent
        ** key columns must be indexed. The check below will pick up this
        ** case.  */
        FKey *pFKey;
        assert( IsOrdinaryTable(pTab) );
        for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pFKey->pNextFrom){
          int j;
          for(j=0; j<pFKey->nCol; j++){
            if( pFKey->aCol[j].iFrom==iCol ){
              zFault = "foreign key";
            }
          }
        }
      }
#endif
      for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
        int j;
        for(j=0; j<pIdx->nKeyCol; j++){
          /* FIXME: Be smarter about indexes that use expressions */
          if( pIdx->aiColumn[j]==iCol || pIdx->aiColumn[j]==XN_EXPR ){
            zFault = "indexed";
          }
        }
      }
      if( zFault ){
        sqlite3DbFree(db, zErr);
        zErr = sqlite3MPrintf(db, "cannot open %s column for writing", zFault);
        rc = SQLITE_ERROR;
        sqlite3BtreeLeaveAll(db);
        goto blob_open_out;
      }
    }

    pBlob->pStmt = (sqlite3_stmt *)sqlite3VdbeCreate(&sParse);
    assert( pBlob->pStmt || db->mallocFailed );
    if( pBlob->pStmt ){

      /* This VDBE program seeks a btree cursor to the identified
      ** db/table/row entry. The reason for using a vdbe program instead
      ** of writing code to use the b-tree layer directly is that the
      ** vdbe program will take advantage of the various transaction,
      ** locking and error handling infrastructure built into the vdbe.
      **
      ** After seeking the cursor, the vdbe executes an OP_ResultRow.
      ** Code external to the Vdbe then "borrows" the b-tree cursor and
      ** uses it to implement the blob_read(), blob_write() and
      ** blob_bytes() functions.
      **
      ** The sqlite3_blob_close() function finalizes the vdbe program,
      ** which closes the b-tree cursor and (possibly) commits the
      ** transaction.
      */
      static const int iLn = VDBE_OFFSET_LINENO(2);
      static const VdbeOpList openBlob[] = {
        {OP_TableLock,      0, 0, 0},  /* 0: Acquire a read or write lock */
        {OP_OpenRead,       0, 0, 0},  /* 1: Open a cursor */
        /* blobSeekToRow() will initialize r[1] to the desired rowid */
        {OP_NotExists,      0, 5, 1},  /* 2: Seek the cursor to rowid=r[1] */
        {OP_Column,         0, 0, 1},  /* 3  */
        {OP_ResultRow,      1, 0, 0},  /* 4  */
        {OP_Halt,           0, 0, 0},  /* 5  */
      };
      Vdbe *v = (Vdbe *)pBlob->pStmt;
      VdbeOp *aOp;

      sqlite3VdbeAddOp4Int(v, OP_Transaction, iDb, wrFlag,
                           pTab->pSchema->schema_cookie,
                           pTab->pSchema->iGeneration);
      sqlite3VdbeChangeP5(v, 1);
      assert( sqlite3VdbeCurrentAddr(v)==2 || db->mallocFailed );
      aOp = sqlite3VdbeAddOpList(v, ArraySize(openBlob), openBlob, iLn);

      /* Make sure a mutex is held on the table to be accessed */
      sqlite3VdbeUsesBtree(v, iDb);

      if( db->mallocFailed==0 ){
        assert( aOp!=0 );
        /* Configure the OP_TableLock instruction */
#ifdef SQLITE_OMIT_SHARED_CACHE
        aOp[0].opcode = OP_Noop;
#else
        aOp[0].p1 = iDb;
        aOp[0].p2 = pTab->tnum;
        aOp[0].p3 = wrFlag;
        sqlite3VdbeChangeP4(v, 2, pTab->zName, P4_TRANSIENT);
      }
      if( db->mallocFailed==0 ){
#endif

        /* Remove either the OP_OpenWrite or OpenRead. Set the P2
        ** parameter of the other to pTab->tnum.  */
        if( wrFlag ) aOp[1].opcode = OP_OpenWrite;
        aOp[1].p2 = pTab->tnum;
        aOp[1].p3 = iDb;

        /* Configure the number of columns. Configure the cursor to
        ** think that the table has one more column than it really
        ** does. An OP_Column to retrieve this imaginary column will
        ** always return an SQL NULL. This is useful because it means
        ** we can invoke OP_Column to fill in the vdbe cursors type
        ** and offset cache without causing any IO.
        */
        aOp[1].p4type = P4_INT32;
        aOp[1].p4.i = pTab->nCol+1;
        aOp[3].p2 = pTab->nCol;

        sParse.nVar = 0;
        sParse.nMem = 1;
        sParse.nTab = 1;
        sqlite3VdbeMakeReady(v, &sParse);
      }
    }

    pBlob->iCol = iCol;
    pBlob->db = db;
    sqlite3BtreeLeaveAll(db);
    if( db->mallocFailed ){
      goto blob_open_out;
    }
    rc = blobSeekToRow(pBlob, iRow, &zErr);
    if( (++nAttempt)>=SQLITE_MAX_SCHEMA_RETRY || rc!=SQLITE_SCHEMA ) break;
    sqlite3ParseObjectReset(&sParse);
  }

blob_open_out:
  if( rc==SQLITE_OK && db->mallocFailed==0 ){
    *ppBlob = (sqlite3_blob *)pBlob;
  }else{
    if( pBlob && pBlob->pStmt ) sqlite3VdbeFinalize((Vdbe *)pBlob->pStmt);
    sqlite3DbFree(db, pBlob);
  }
  sqlite3ErrorWithMsg(db, rc, (zErr ? "%s" : (char*)0), zErr);
  sqlite3DbFree(db, zErr);
  sqlite3ParseObjectReset(&sParse);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

/*
** Close a blob handle that was previously created using
** sqlite3_blob_open().
*/
SQLITE_API int sqlite3_blob_close(sqlite3_blob *pBlob){
  Incrblob *p = (Incrblob *)pBlob;
  int rc;
  sqlite3 *db;

  if( p ){
    sqlite3_stmt *pStmt = p->pStmt;
    db = p->db;
    sqlite3_mutex_enter(db->mutex);
    sqlite3DbFree(db, p);
    sqlite3_mutex_leave(db->mutex);
    rc = sqlite3_finalize(pStmt);
  }else{
    rc = SQLITE_OK;
  }
  return rc;
}

/*
** Perform a read or write operation on a blob
*/
static int blobReadWrite(
  sqlite3_blob *pBlob,
  void *z,
  int n,
  int iOffset,
  int (*xCall)(BtCursor*, u32, u32, void*)
){
  int rc = SQLITE_OK;
  Incrblob *p = (Incrblob *)pBlob;
  Vdbe *v;
  sqlite3 *db;

  if( p==0 ) return SQLITE_MISUSE_BKPT;
  db = p->db;
  sqlite3_mutex_enter(db->mutex);
  v = (Vdbe*)p->pStmt;

  if( n<0 || iOffset<0 || ((sqlite3_int64)iOffset+n)>p->nByte ){
    /* Request is out of range. Return a transient error. */
    rc = SQLITE_ERROR;
  }else if( v==0 ){
    /* If there is no statement handle, then the blob-handle has
    ** already been invalidated. Return SQLITE_ABORT in this case.
    */
    rc = SQLITE_ABORT;
  }else{
    /* Call either BtreeData() or BtreePutData(). If SQLITE_ABORT is
    ** returned, clean-up the statement handle.
    */
    assert( db == v->db );
    sqlite3BtreeEnterCursor(p->pCsr);

#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
    if( xCall==sqlite3BtreePutData && db->xPreUpdateCallback ){
      /* If a pre-update hook is registered and this is a write cursor,
      ** invoke it here.
      **
      ** TODO: The preupdate-hook is passed SQLITE_DELETE, even though this
      ** operation should really be an SQLITE_UPDATE. This is probably
      ** incorrect, but is convenient because at this point the new.* values
      ** are not easily obtainable. And for the sessions module, an
      ** SQLITE_UPDATE where the PK columns do not change is handled in the
      ** same way as an SQLITE_DELETE (the SQLITE_DELETE code is actually
      ** slightly more efficient). Since you cannot write to a PK column
      ** using the incremental-blob API, this works. For the sessions module
      ** anyhow.
      */
      if( sqlite3BtreeCursorIsValidNN(p->pCsr)==0 ){
        /* If the cursor is not currently valid, try to reseek it. This
        ** always either fails or finds the correct row - the cursor will
        ** have been marked permanently CURSOR_INVALID if the open row has
        ** been deleted.  */
        int bDiff = 0;
        rc = sqlite3BtreeCursorRestore(p->pCsr, &bDiff);
        assert( bDiff==0 || sqlite3BtreeCursorIsValidNN(p->pCsr)==0 );
      }
      if( sqlite3BtreeCursorIsValidNN(p->pCsr) ){
        sqlite3_int64 iKey;
        iKey = sqlite3BtreeIntegerKey(p->pCsr);
        assert( v->apCsr[0]!=0 );
        assert( v->apCsr[0]->eCurType==CURTYPE_BTREE );
        sqlite3VdbePreUpdateHook(
            v, v->apCsr[0], SQLITE_DELETE, p->zDb, p->pTab, iKey, -1, p->iCol
        );
      }
    }
    if( rc==SQLITE_OK ){
      rc = xCall(p->pCsr, iOffset+p->iOffset, n, z);
    }
#else
    rc = xCall(p->pCsr, iOffset+p->iOffset, n, z);
#endif

    sqlite3BtreeLeaveCursor(p->pCsr);
    if( rc==SQLITE_ABORT ){
      sqlite3VdbeFinalize(v);
      p->pStmt = 0;
    }else{
      v->rc = rc;
    }
  }
  sqlite3Error(db, rc);
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

/*
** Read data from a blob handle.
*/
SQLITE_API int sqlite3_blob_read(sqlite3_blob *pBlob, void *z, int n, int iOffset){
  return blobReadWrite(pBlob, z, n, iOffset, sqlite3BtreePayloadChecked);
}

/*
** Write data to a blob handle.
*/
SQLITE_API int sqlite3_blob_write(sqlite3_blob *pBlob, const void *z, int n, int iOffset){
  return blobReadWrite(pBlob, (void *)z, n, iOffset, sqlite3BtreePutData);
}

/*
** Query a blob handle for the size of the data.
**
** The Incrblob.nByte field is fixed for the lifetime of the Incrblob
** so no mutex is required for access.
*/
SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *pBlob){
  Incrblob *p = (Incrblob *)pBlob;
  return (p && p->pStmt) ? p->nByte : 0;

sqlite3.c  view on Meta::CPAN

  if( p->pStmt==0 ){
    /* If there is no statement handle, then the blob-handle has
    ** already been invalidated. Return SQLITE_ABORT in this case.
    */
    rc = SQLITE_ABORT;
  }else{
    char *zErr;
    ((Vdbe*)p->pStmt)->rc = SQLITE_OK;
    rc = blobSeekToRow(p, iRow, &zErr);
    if( rc!=SQLITE_OK ){
      sqlite3ErrorWithMsg(db, rc, (zErr ? "%s" : (char*)0), zErr);
      sqlite3DbFree(db, zErr);
    }
    assert( rc!=SQLITE_SCHEMA );
  }

  rc = sqlite3ApiExit(db, rc);
  assert( rc==SQLITE_OK || p->pStmt==0 );
  sqlite3_mutex_leave(db->mutex);
  return rc;
}

#endif /* #ifndef SQLITE_OMIT_INCRBLOB */

/************** End of vdbeblob.c ********************************************/
/************** Begin file vdbesort.c ****************************************/
/*
** 2011-07-09
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code for the VdbeSorter object, used in concert with
** a VdbeCursor to sort large numbers of keys for CREATE INDEX statements
** or by SELECT statements with ORDER BY clauses that cannot be satisfied
** using indexes and without LIMIT clauses.
**
** The VdbeSorter object implements a multi-threaded external merge sort
** algorithm that is efficient even if the number of elements being sorted
** exceeds the available memory.
**
** Here is the (internal, non-API) interface between this module and the
** rest of the SQLite system:
**
**    sqlite3VdbeSorterInit()       Create a new VdbeSorter object.
**
**    sqlite3VdbeSorterWrite()      Add a single new row to the VdbeSorter
**                                  object.  The row is a binary blob in the
**                                  OP_MakeRecord format that contains both
**                                  the ORDER BY key columns and result columns
**                                  in the case of a SELECT w/ ORDER BY, or
**                                  the complete record for an index entry
**                                  in the case of a CREATE INDEX.
**
**    sqlite3VdbeSorterRewind()     Sort all content previously added.
**                                  Position the read cursor on the
**                                  first sorted element.
**
**    sqlite3VdbeSorterNext()       Advance the read cursor to the next sorted
**                                  element.
**
**    sqlite3VdbeSorterRowkey()     Return the complete binary blob for the
**                                  row currently under the read cursor.
**
**    sqlite3VdbeSorterCompare()    Compare the binary blob for the row
**                                  currently under the read cursor against
**                                  another binary blob X and report if
**                                  X is strictly less than the read cursor.
**                                  Used to enforce uniqueness in a
**                                  CREATE UNIQUE INDEX statement.
**
**    sqlite3VdbeSorterClose()      Close the VdbeSorter object and reclaim
**                                  all resources.
**
**    sqlite3VdbeSorterReset()      Refurbish the VdbeSorter for reuse.  This
**                                  is like Close() followed by Init() only
**                                  much faster.
**
** The interfaces above must be called in a particular order.  Write() can
** only occur in between Init()/Reset() and Rewind().  Next(), Rowkey(), and
** Compare() can only occur in between Rewind() and Close()/Reset(). i.e.
**
**   Init()
**   for each record: Write()
**   Rewind()
**     Rowkey()/Compare()
**   Next()
**   Close()
**
** Algorithm:
**
** Records passed to the sorter via calls to Write() are initially held
** unsorted in main memory. Assuming the amount of memory used never exceeds
** a threshold, when Rewind() is called the set of records is sorted using
** an in-memory merge sort. In this case, no temporary files are required
** and subsequent calls to Rowkey(), Next() and Compare() read records
** directly from main memory.
**
** If the amount of space used to store records in main memory exceeds the
** threshold, then the set of records currently in memory are sorted and
** written to a temporary file in "Packed Memory Array" (PMA) format.
** A PMA created at this point is known as a "level-0 PMA". Higher levels
** of PMAs may be created by merging existing PMAs together - for example
** merging two or more level-0 PMAs together creates a level-1 PMA.
**
** The threshold for the amount of main memory to use before flushing
** records to a PMA is roughly the same as the limit configured for the
** page-cache of the main database. Specifically, the threshold is set to
** the value returned by "PRAGMA main.page_size" multiplied by
** that returned by "PRAGMA main.cache_size", in bytes.
**
** If the sorter is running in single-threaded mode, then all PMAs generated
** are appended to a single temporary file. Or, if the sorter is running in
** multi-threaded mode then up to (N+1) temporary files may be opened, where
** N is the configured number of worker threads. In this case, instead of
** sorting the records and writing the PMA to a temporary file itself, the
** calling thread usually launches a worker thread to do so. Except, if
** there are already N worker threads running, the main thread does the work
** itself.
**
** The sorter is running in multi-threaded mode if (a) the library was built
** with pre-processor symbol SQLITE_MAX_WORKER_THREADS set to a value greater
** than zero, and (b) worker threads have been enabled at runtime by calling
** "PRAGMA threads=N" with some value of N greater than 0.
**
** When Rewind() is called, any data remaining in memory is flushed to a
** final PMA. So at this point the data is stored in some number of sorted
** PMAs within temporary files on disk.

sqlite3.c  view on Meta::CPAN

**
** In other words, each time we advance to the next sorter element, log2(N)
** key comparison operations are required, where N is the number of segments
** being merged (rounded up to the next power of 2).
*/
struct MergeEngine {
  int nTree;                 /* Used size of aTree/aReadr (power of 2) */
  SortSubtask *pTask;        /* Used by this thread only */
  int *aTree;                /* Current state of incremental merge */
  PmaReader *aReadr;         /* Array of PmaReaders to merge data from */
};

/*
** This object represents a single thread of control in a sort operation.
** Exactly VdbeSorter.nTask instances of this object are allocated
** as part of each VdbeSorter object. Instances are never allocated any
** other way. VdbeSorter.nTask is set to the number of worker threads allowed
** (see SQLITE_CONFIG_WORKER_THREADS) plus one (the main thread).  Thus for
** single-threaded operation, there is exactly one instance of this object
** and for multi-threaded operation there are two or more instances.
**
** Essentially, this structure contains all those fields of the VdbeSorter
** structure for which each thread requires a separate instance. For example,
** each thread requeries its own UnpackedRecord object to unpack records in
** as part of comparison operations.
**
** Before a background thread is launched, variable bDone is set to 0. Then,
** right before it exits, the thread itself sets bDone to 1. This is used for
** two purposes:
**
**   1. When flushing the contents of memory to a level-0 PMA on disk, to
**      attempt to select a SortSubtask for which there is not already an
**      active background thread (since doing so causes the main thread
**      to block until it finishes).
**
**   2. If SQLITE_DEBUG_SORTER_THREADS is defined, to determine if a call
**      to sqlite3ThreadJoin() is likely to block. Cases that are likely to
**      block provoke debugging output.
**
** In both cases, the effects of the main thread seeing (bDone==0) even
** after the thread has finished are not dire. So we don't worry about
** memory barriers and such here.
*/
typedef int (*SorterCompare)(SortSubtask*,int*,const void*,int,const void*,int);
struct SortSubtask {
  SQLiteThread *pThread;          /* Background thread, if any */
  int bDone;                      /* Set if thread is finished but not joined */
  int nPMA;                       /* Number of PMAs currently in file */
  VdbeSorter *pSorter;            /* Sorter that owns this sub-task */
  UnpackedRecord *pUnpacked;      /* Space to unpack a record */
  SorterList list;                /* List for thread to write to a PMA */
  SorterCompare xCompare;         /* Compare function to use */
  SorterFile file;                /* Temp file for level-0 PMAs */
  SorterFile file2;               /* Space for other PMAs */
  u64 nSpill;                     /* Total bytes written by this task */
};


/*
** Main sorter structure. A single instance of this is allocated for each
** sorter cursor created by the VDBE.
**
** mxKeysize:
**   As records are added to the sorter by calls to sqlite3VdbeSorterWrite(),
**   this variable is updated so as to be set to the size on disk of the
**   largest record in the sorter.
*/
struct VdbeSorter {
  int mnPmaSize;                  /* Minimum PMA size, in bytes */
  int mxPmaSize;                  /* Maximum PMA size, in bytes.  0==no limit */
  int mxKeysize;                  /* Largest serialized key seen so far */
  int pgsz;                       /* Main database page size */
  PmaReader *pReader;             /* Readr data from here after Rewind() */
  MergeEngine *pMerger;           /* Or here, if bUseThreads==0 */
  sqlite3 *db;                    /* Database connection */
  KeyInfo *pKeyInfo;              /* How to compare records */
  UnpackedRecord *pUnpacked;      /* Used by VdbeSorterCompare() */
  SorterList list;                /* List of in-memory records */
  int iMemory;                    /* Offset of free space in list.aMemory */
  int nMemory;                    /* Size of list.aMemory allocation in bytes */
  u8 bUsePMA;                     /* True if one or more PMAs created */
  u8 bUseThreads;                 /* True to use background threads */
  u8 iPrev;                       /* Previous thread used to flush PMA */
  u8 nTask;                       /* Size of aTask[] array */
  u8 typeMask;
  SortSubtask aTask[FLEXARRAY];   /* One or more subtasks */
};

/* Size (in bytes) of a VdbeSorter object that works with N or fewer subtasks */
#define SZ_VDBESORTER(N)  (offsetof(VdbeSorter,aTask)+(N)*sizeof(SortSubtask))

#define SORTER_TYPE_INTEGER 0x01
#define SORTER_TYPE_TEXT    0x02

/*
** An instance of the following object is used to read records out of a
** PMA, in sorted order.  The next key to be read is cached in nKey/aKey.
** aKey might point into aMap or into aBuffer.  If neither of those locations
** contain a contiguous representation of the key, then aAlloc is allocated
** and the key is copied into aAlloc and aKey is made to point to aAlloc.
**
** pFd==0 at EOF.
*/
struct PmaReader {
  i64 iReadOff;               /* Current read offset */
  i64 iEof;                   /* 1 byte past EOF for this PmaReader */
  int nAlloc;                 /* Bytes of space at aAlloc */
  int nKey;                   /* Number of bytes in key */
  sqlite3_file *pFd;          /* File handle we are reading from */
  u8 *aAlloc;                 /* Space for aKey if aBuffer and pMap wont work */
  u8 *aKey;                   /* Pointer to current key */
  u8 *aBuffer;                /* Current read buffer */
  int nBuffer;                /* Size of read buffer in bytes */
  u8 *aMap;                   /* Pointer to mapping of entire file */
  IncrMerger *pIncr;          /* Incremental merger */
};

/*
** Normally, a PmaReader object iterates through an existing PMA stored
** within a temp file. However, if the PmaReader.pIncr variable points to
** an object of the following type, it may be used to iterate/merge through

sqlite3.c  view on Meta::CPAN


  return SQLITE_OK;
}

/*
** Read a varint from the stream of data accessed by p. Set *pnOut to
** the value read.
*/
static int vdbePmaReadVarint(PmaReader *p, u64 *pnOut){
  int iBuf;

  if( p->aMap ){
    p->iReadOff += sqlite3GetVarint(&p->aMap[p->iReadOff], pnOut);
  }else{
    iBuf = p->iReadOff % p->nBuffer;
    if( iBuf && (p->nBuffer-iBuf)>=9 ){
      p->iReadOff += sqlite3GetVarint(&p->aBuffer[iBuf], pnOut);
    }else{
      u8 aVarint[16], *a;
      int i = 0, rc;
      do{
        rc = vdbePmaReadBlob(p, 1, &a);
        if( rc ) return rc;
        aVarint[(i++)&0xf] = a[0];
      }while( (a[0]&0x80)!=0 );
      sqlite3GetVarint(aVarint, pnOut);
    }
  }

  return SQLITE_OK;
}

/*
** Attempt to memory map file pFile. If successful, set *pp to point to the
** new mapping and return SQLITE_OK. If the mapping is not attempted
** (because the file is too large or the VFS layer is configured not to use
** mmap), return SQLITE_OK and set *pp to NULL.
**
** Or, if an error occurs, return an SQLite error code. The final value of
** *pp is undefined in this case.
*/
static int vdbeSorterMapFile(SortSubtask *pTask, SorterFile *pFile, u8 **pp){
  int rc = SQLITE_OK;
  if( pFile->iEof<=(i64)(pTask->pSorter->db->nMaxSorterMmap) ){
    sqlite3_file *pFd = pFile->pFd;
    if( pFd->pMethods->iVersion>=3 ){
      rc = sqlite3OsFetch(pFd, 0, (int)pFile->iEof, (void**)pp);
      testcase( rc!=SQLITE_OK );
    }
  }
  return rc;
}

/*
** Attach PmaReader pReadr to file pFile (if it is not already attached to
** that file) and seek it to offset iOff within the file.  Return SQLITE_OK
** if successful, or an SQLite error code if an error occurs.
*/
static int vdbePmaReaderSeek(
  SortSubtask *pTask,             /* Task context */
  PmaReader *pReadr,              /* Reader whose cursor is to be moved */
  SorterFile *pFile,              /* Sorter file to read from */
  i64 iOff                        /* Offset in pFile */
){
  int rc = SQLITE_OK;

  assert( pReadr->pIncr==0 || pReadr->pIncr->bEof==0 );

  if( sqlite3FaultSim(201) ) return SQLITE_IOERR_READ;
  if( pReadr->aMap ){
    sqlite3OsUnfetch(pReadr->pFd, 0, pReadr->aMap);
    pReadr->aMap = 0;
  }
  pReadr->iReadOff = iOff;
  pReadr->iEof = pFile->iEof;
  pReadr->pFd = pFile->pFd;

  rc = vdbeSorterMapFile(pTask, pFile, &pReadr->aMap);
  if( rc==SQLITE_OK && pReadr->aMap==0 ){
    int pgsz = pTask->pSorter->pgsz;
    int iBuf = pReadr->iReadOff % pgsz;
    if( pReadr->aBuffer==0 ){
      pReadr->aBuffer = (u8*)sqlite3Malloc(pgsz);
      if( pReadr->aBuffer==0 ) rc = SQLITE_NOMEM_BKPT;
      pReadr->nBuffer = pgsz;
    }
    if( rc==SQLITE_OK && iBuf ){
      int nRead = pgsz - iBuf;
      if( (pReadr->iReadOff + nRead) > pReadr->iEof ){
        nRead = (int)(pReadr->iEof - pReadr->iReadOff);
      }
      rc = sqlite3OsRead(
          pReadr->pFd, &pReadr->aBuffer[iBuf], nRead, pReadr->iReadOff
      );
      testcase( rc!=SQLITE_OK );
    }
  }

  return rc;
}

/*
** Advance PmaReader pReadr to the next key in its PMA. Return SQLITE_OK if
** no error occurs, or an SQLite error code if one does.
*/
static int vdbePmaReaderNext(PmaReader *pReadr){
  int rc = SQLITE_OK;             /* Return Code */
  u64 nRec = 0;                   /* Size of record in bytes */


  if( pReadr->iReadOff>=pReadr->iEof ){
    IncrMerger *pIncr = pReadr->pIncr;
    int bEof = 1;
    if( pIncr ){
      rc = vdbeIncrSwap(pIncr);
      if( rc==SQLITE_OK && pIncr->bEof==0 ){
        rc = vdbePmaReaderSeek(
            pIncr->pTask, pReadr, &pIncr->aFile[0], pIncr->iStartOff
        );
        bEof = 0;
      }

sqlite3.c  view on Meta::CPAN

  const u8 * const p1 = (const u8 * const)pKey1;
  const u8 * const p2 = (const u8 * const)pKey2;
  const int s1 = p1[1];                 /* Left hand serial type */
  const int s2 = p2[1];                 /* Right hand serial type */
  const u8 * const v1 = &p1[ p1[0] ];   /* Pointer to value 1 */
  const u8 * const v2 = &p2[ p2[0] ];   /* Pointer to value 2 */
  int res;                              /* Return value */

  assert( (s1>0 && s1<7) || s1==8 || s1==9 );
  assert( (s2>0 && s2<7) || s2==8 || s2==9 );

  if( s1==s2 ){
    /* The two values have the same sign. Compare using memcmp(). */
    static const u8 aLen[] = {0, 1, 2, 3, 4, 6, 8, 0, 0, 0 };
    const u8 n = aLen[s1];
    int i;
    res = 0;
    for(i=0; i<n; i++){
      if( (res = v1[i] - v2[i])!=0 ){
        if( ((v1[0] ^ v2[0]) & 0x80)!=0 ){
          res = v1[0] & 0x80 ? -1 : +1;
        }
        break;
      }
    }
  }else if( s1>7 && s2>7 ){
    res = s1 - s2;
  }else{
    if( s2>7 ){
      res = +1;
    }else if( s1>7 ){
      res = -1;
    }else{
      res = s1 - s2;
    }
    assert( res!=0 );

    if( res>0 ){
      if( *v1 & 0x80 ) res = -1;
    }else{
      if( *v2 & 0x80 ) res = +1;
    }
  }

  assert( pTask->pSorter->pKeyInfo->aSortFlags!=0 );
  if( res==0 ){
    if( pTask->pSorter->pKeyInfo->nKeyField>1 ){
      res = vdbeSorterCompareTail(
          pTask, pbKey2Cached, pKey1, nKey1, pKey2, nKey2
      );
    }
  }else if( pTask->pSorter->pKeyInfo->aSortFlags[0] ){
    assert( !(pTask->pSorter->pKeyInfo->aSortFlags[0]&KEYINFO_ORDER_BIGNULL) );
    res = res * -1;
  }

  return res;
}

/*
** Initialize the temporary index cursor just opened as a sorter cursor.
**
** Usually, the sorter module uses the value of (pCsr->pKeyInfo->nKeyField)
** to determine the number of fields that should be compared from the
** records being sorted. However, if the value passed as argument nField
** is non-zero and the sorter is able to guarantee a stable sort, nField
** is used instead. This is used when sorting records for a CREATE INDEX
** statement. In this case, keys are always delivered to the sorter in
** order of the primary key, which happens to be make up the final part
** of the records being sorted. So if the sort is stable, there is never
** any reason to compare PK fields and they can be ignored for a small
** performance boost.
**
** The sorter can guarantee a stable sort when running in single-threaded
** mode, but not in multi-threaded mode.
**
** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
*/
SQLITE_PRIVATE int sqlite3VdbeSorterInit(
  sqlite3 *db,                    /* Database connection (for malloc()) */
  int nField,                     /* Number of key fields in each record */
  VdbeCursor *pCsr                /* Cursor that holds the new sorter */
){
  int pgsz;                       /* Page size of main database */
  int i;                          /* Used to iterate through aTask[] */
  VdbeSorter *pSorter;            /* The new sorter */
  KeyInfo *pKeyInfo;              /* Copy of pCsr->pKeyInfo with db==0 */
  int szKeyInfo;                  /* Size of pCsr->pKeyInfo in bytes */
  i64 sz;                         /* Size of pSorter in bytes */
  int rc = SQLITE_OK;
#if SQLITE_MAX_WORKER_THREADS==0
# define nWorker 0
#else
  int nWorker;
#endif

  /* Initialize the upper limit on the number of worker threads */
#if SQLITE_MAX_WORKER_THREADS>0
  if( sqlite3TempInMemory(db) || sqlite3GlobalConfig.bCoreMutex==0 ){
    nWorker = 0;
  }else{
    nWorker = db->aLimit[SQLITE_LIMIT_WORKER_THREADS];
  }
#endif

  /* Do not allow the total number of threads (main thread + all workers)
  ** to exceed the maximum merge count */
#if SQLITE_MAX_WORKER_THREADS>=SORTER_MAX_MERGE_COUNT
  if( nWorker>=SORTER_MAX_MERGE_COUNT ){
    nWorker = SORTER_MAX_MERGE_COUNT-1;
  }
#endif

  assert( pCsr->pKeyInfo );
  assert( !pCsr->isEphemeral );
  assert( pCsr->eCurType==CURTYPE_SORTER );
  assert( sizeof(KeyInfo) + UMXV(pCsr->pKeyInfo->nKeyField)*sizeof(CollSeq*)
               < 0x7fffffff );
  assert( pCsr->pKeyInfo->nKeyField<=pCsr->pKeyInfo->nAllField );
  szKeyInfo = SZ_KEYINFO(pCsr->pKeyInfo->nAllField);
  sz = SZ_VDBESORTER(nWorker+1);

sqlite3.c  view on Meta::CPAN


/*
** Allocate a new MergeEngine object capable of handling up to
** nReader PmaReader inputs.
**
** nReader is automatically rounded up to the next power of two.
** nReader may not exceed SORTER_MAX_MERGE_COUNT even after rounding up.
*/
static MergeEngine *vdbeMergeEngineNew(int nReader){
  int N = 2;                      /* Smallest power of two >= nReader */
  i64 nByte;                      /* Total bytes of space to allocate */
  MergeEngine *pNew;              /* Pointer to allocated object to return */

  assert( nReader<=SORTER_MAX_MERGE_COUNT );

  while( N<nReader ) N += N;
  nByte = sizeof(MergeEngine) + N * (sizeof(int) + sizeof(PmaReader));

  pNew = sqlite3FaultSim(100) ? 0 : (MergeEngine*)sqlite3MallocZero(nByte);
  if( pNew ){
    pNew->nTree = N;
    pNew->pTask = 0;
    pNew->aReadr = (PmaReader*)&pNew[1];
    pNew->aTree = (int*)&pNew->aReadr[N];
  }
  return pNew;
}

/*
** Free the MergeEngine object passed as the only argument.
*/
static void vdbeMergeEngineFree(MergeEngine *pMerger){
  int i;
  if( pMerger ){
    for(i=0; i<pMerger->nTree; i++){
      vdbePmaReaderClear(&pMerger->aReadr[i]);
    }
  }
  sqlite3_free(pMerger);
}

/*
** Free all resources associated with the IncrMerger object indicated by
** the first argument.
*/
static void vdbeIncrFree(IncrMerger *pIncr){
  if( pIncr ){
#if SQLITE_MAX_WORKER_THREADS>0
    if( pIncr->bUseThread ){
      vdbeSorterJoinThread(pIncr->pTask);
      if( pIncr->aFile[0].pFd ) sqlite3OsCloseFree(pIncr->aFile[0].pFd);
      if( pIncr->aFile[1].pFd ) sqlite3OsCloseFree(pIncr->aFile[1].pFd);
    }
#endif
    vdbeMergeEngineFree(pIncr->pMerger);
    sqlite3_free(pIncr);
  }
}

/*
** Reset a sorting cursor back to its original empty state.
*/
SQLITE_PRIVATE void sqlite3VdbeSorterReset(sqlite3 *db, VdbeSorter *pSorter){
  int i;
  (void)vdbeSorterJoinAll(pSorter, SQLITE_OK);
  assert( pSorter->bUseThreads || pSorter->pReader==0 );
#if SQLITE_MAX_WORKER_THREADS>0
  if( pSorter->pReader ){
    vdbePmaReaderClear(pSorter->pReader);
    sqlite3DbFree(db, pSorter->pReader);
    pSorter->pReader = 0;
  }
#endif
  vdbeMergeEngineFree(pSorter->pMerger);
  pSorter->pMerger = 0;
  for(i=0; i<pSorter->nTask; i++){
    SortSubtask *pTask = &pSorter->aTask[i];
    vdbeSortSubtaskCleanup(db, pTask);
    pTask->pSorter = pSorter;
  }
  if( pSorter->list.aMemory==0 ){
    vdbeSorterRecordFree(0, pSorter->list.pList);
  }
  pSorter->list.pList = 0;
  pSorter->list.szPMA = 0;
  pSorter->bUsePMA = 0;
  pSorter->iMemory = 0;
  pSorter->mxKeysize = 0;
  sqlite3DbFree(db, pSorter->pUnpacked);
  pSorter->pUnpacked = 0;
}

/*
** Free any cursor components allocated by sqlite3VdbeSorterXXX routines.
*/
SQLITE_PRIVATE void sqlite3VdbeSorterClose(sqlite3 *db, VdbeCursor *pCsr){
  VdbeSorter *pSorter;
  assert( pCsr->eCurType==CURTYPE_SORTER );
  pSorter = pCsr->uc.pSorter;
  if( pSorter ){
    /* Increment db->nSpill by the total number of bytes of data written
    ** to temp files by this sort operation.  */
    int ii;
    for(ii=0; ii<pSorter->nTask; ii++){
      db->nSpill += pSorter->aTask[ii].nSpill;
    }
    sqlite3VdbeSorterReset(db, pSorter);
    sqlite3_free(pSorter->list.aMemory);
    sqlite3DbFree(db, pSorter);
    pCsr->uc.pSorter = 0;
  }
}

#if SQLITE_MAX_MMAP_SIZE>0
/*
** The first argument is a file-handle open on a temporary file. The file
** is guaranteed to be nByte bytes or smaller in size. This function
** attempts to extend the file to nByte bytes in size and to ensure that
** the VFS has memory mapped it.
**
** Whether or not the file does end up memory mapped of course depends on
** the specific VFS implementation.
*/
static void vdbeSorterExtendFile(sqlite3 *db, sqlite3_file *pFd, i64 nByte){
  if( nByte<=(i64)(db->nMaxSorterMmap) && pFd->pMethods->iVersion>=3 ){
    void *p = 0;
    int chunksize = 4*1024;
    sqlite3OsFileControlHint(pFd, SQLITE_FCNTL_CHUNK_SIZE, &chunksize);
    sqlite3OsFileControlHint(pFd, SQLITE_FCNTL_SIZE_HINT, &nByte);
    sqlite3OsFetch(pFd, 0, (int)nByte, &p);
    if( p ) sqlite3OsUnfetch(pFd, 0, p);
  }
}
#else
# define vdbeSorterExtendFile(x,y,z)
#endif

/*
** Allocate space for a file-handle and open a temporary file. If successful,
** set *ppFd to point to the malloc'd file-handle and return SQLITE_OK.
** Otherwise, set *ppFd to 0 and return an SQLite error code.
*/
static int vdbeSorterOpenTempFile(
  sqlite3 *db,                    /* Database handle doing sort */
  i64 nExtend,                    /* Attempt to extend file to this size */
  sqlite3_file **ppFd
){
  int rc;
  if( sqlite3FaultSim(202) ) return SQLITE_IOERR_ACCESS;
  rc = sqlite3OsOpenMalloc(db->pVfs, 0, ppFd,
      SQLITE_OPEN_TEMP_JOURNAL |
      SQLITE_OPEN_READWRITE    | SQLITE_OPEN_CREATE |
      SQLITE_OPEN_EXCLUSIVE    | SQLITE_OPEN_DELETEONCLOSE, &rc
  );

sqlite3.c  view on Meta::CPAN

  ** Or will be, anyhow.  */
  pSorter->bUsePMA = 1;

  /* Select a sub-task to sort and flush the current list of in-memory
  ** records to disk. If the sorter is running in multi-threaded mode,
  ** round-robin between the first (pSorter->nTask-1) tasks. Except, if
  ** the background thread from a sub-tasks previous turn is still running,
  ** skip it. If the first (pSorter->nTask-1) sub-tasks are all still busy,
  ** fall back to using the final sub-task. The first (pSorter->nTask-1)
  ** sub-tasks are preferred as they use background threads - the final
  ** sub-task uses the main thread. */
  for(i=0; i<nWorker; i++){
    int iTest = (pSorter->iPrev + i + 1) % nWorker;
    pTask = &pSorter->aTask[iTest];
    if( pTask->bDone ){
      rc = vdbeSorterJoinThread(pTask);
    }
    if( rc!=SQLITE_OK || pTask->pThread==0 ) break;
  }

  if( rc==SQLITE_OK ){
    if( i==nWorker ){
      /* Use the foreground thread for this operation */
      rc = vdbeSorterListToPMA(&pSorter->aTask[nWorker], &pSorter->list);
    }else{
      /* Launch a background thread for this operation */
      u8 *aMem;
      void *pCtx;

      assert( pTask!=0 );
      assert( pTask->pThread==0 && pTask->bDone==0 );
      assert( pTask->list.pList==0 );
      assert( pTask->list.aMemory==0 || pSorter->list.aMemory!=0 );

      aMem = pTask->list.aMemory;
      pCtx = (void*)pTask;
      pSorter->iPrev = (u8)(pTask - pSorter->aTask);
      pTask->list = pSorter->list;
      pSorter->list.pList = 0;
      pSorter->list.szPMA = 0;
      if( aMem ){
        pSorter->list.aMemory = aMem;
        pSorter->nMemory = sqlite3MallocSize(aMem);
      }else if( pSorter->list.aMemory ){
        pSorter->list.aMemory = sqlite3Malloc(pSorter->nMemory);
        if( !pSorter->list.aMemory ) return SQLITE_NOMEM_BKPT;
      }

      rc = vdbeSorterCreateThread(pTask, vdbeSorterFlushThread, pCtx);
    }
  }

  return rc;
#endif /* SQLITE_MAX_WORKER_THREADS!=0 */
}

/*
** Add a record to the sorter.
*/
SQLITE_PRIVATE int sqlite3VdbeSorterWrite(
  const VdbeCursor *pCsr,         /* Sorter cursor */
  Mem *pVal                       /* Memory cell containing record */
){
  VdbeSorter *pSorter;
  int rc = SQLITE_OK;             /* Return Code */
  SorterRecord *pNew;             /* New list element */
  int bFlush;                     /* True to flush contents of memory to PMA */
  i64 nReq;                       /* Bytes of memory required */
  i64 nPMA;                       /* Bytes of PMA space required */
  int t;                          /* serial type of first record field */

  assert( pCsr->eCurType==CURTYPE_SORTER );
  pSorter = pCsr->uc.pSorter;
  getVarint32NR((const u8*)&pVal->z[1], t);
  if( t>0 && t<10 && t!=7 ){
    pSorter->typeMask &= SORTER_TYPE_INTEGER;
  }else if( t>10 && (t & 0x01) ){
    pSorter->typeMask &= SORTER_TYPE_TEXT;
  }else{
    pSorter->typeMask = 0;
  }

  assert( pSorter );

  /* Figure out whether or not the current contents of memory should be
  ** flushed to a PMA before continuing. If so, do so.
  **
  ** If using the single large allocation mode (pSorter->aMemory!=0), then
  ** flush the contents of memory to a new PMA if (a) at least one value is
  ** already in memory and (b) the new value will not fit in memory.
  **
  ** Or, if using separate allocations for each record, flush the contents
  ** of memory to a PMA if either of the following are true:
  **
  **   * The total memory allocated for the in-memory list is greater
  **     than (page-size * cache-size), or
  **
  **   * The total memory allocated for the in-memory list is greater
  **     than (page-size * 10) and sqlite3HeapNearlyFull() returns true.
  */
  nReq = pVal->n + sizeof(SorterRecord);
  nPMA = pVal->n + sqlite3VarintLen(pVal->n);
  if( pSorter->mxPmaSize ){
    if( pSorter->list.aMemory ){
      bFlush = pSorter->iMemory && (pSorter->iMemory+nReq) > pSorter->mxPmaSize;
    }else{
      bFlush = (
          (pSorter->list.szPMA > pSorter->mxPmaSize)
       || (pSorter->list.szPMA > pSorter->mnPmaSize && sqlite3HeapNearlyFull())
      );
    }
    if( bFlush ){
      rc = vdbeSorterFlushPMA(pSorter);
      pSorter->list.szPMA = 0;
      pSorter->iMemory = 0;
      assert( rc!=SQLITE_OK || pSorter->list.pList==0 );
    }
  }

  pSorter->list.szPMA += nPMA;
  if( nPMA>pSorter->mxKeysize ){

sqlite3.c  view on Meta::CPAN

** If successful, SQLITE_OK is returned. If an error occurs, an SQLite error
** code is returned and pLeaf is freed.
*/
static int vdbeSorterAddToTree(
  SortSubtask *pTask,             /* Task context */
  int nDepth,                     /* Depth of tree according to TreeDepth() */
  int iSeq,                       /* Sequence number of leaf within tree */
  MergeEngine *pRoot,             /* Root of tree */
  MergeEngine *pLeaf              /* Leaf to add to tree */
){
  int rc = SQLITE_OK;
  int nDiv = 1;
  int i;
  MergeEngine *p = pRoot;
  IncrMerger *pIncr;

  rc = vdbeIncrMergerNew(pTask, pLeaf, &pIncr);

  for(i=1; i<nDepth; i++){
    nDiv = nDiv * SORTER_MAX_MERGE_COUNT;
  }

  for(i=1; i<nDepth && rc==SQLITE_OK; i++){
    int iIter = (iSeq / nDiv) % SORTER_MAX_MERGE_COUNT;
    PmaReader *pReadr = &p->aReadr[iIter];

    if( pReadr->pIncr==0 ){
      MergeEngine *pNew = vdbeMergeEngineNew(SORTER_MAX_MERGE_COUNT);
      if( pNew==0 ){
        rc = SQLITE_NOMEM_BKPT;
      }else{
        rc = vdbeIncrMergerNew(pTask, pNew, &pReadr->pIncr);
      }
    }
    if( rc==SQLITE_OK ){
      p = pReadr->pIncr->pMerger;
      nDiv = nDiv / SORTER_MAX_MERGE_COUNT;
    }
  }

  if( rc==SQLITE_OK ){
    p->aReadr[iSeq % SORTER_MAX_MERGE_COUNT].pIncr = pIncr;
  }else{
    vdbeIncrFree(pIncr);
  }
  return rc;
}

/*
** This function is called as part of a SorterRewind() operation on a sorter
** that has already written two or more level-0 PMAs to one or more temp
** files. It builds a tree of MergeEngine/IncrMerger/PmaReader objects that
** can be used to incrementally merge all PMAs on disk.
**
** If successful, SQLITE_OK is returned and *ppOut set to point to the
** MergeEngine object at the root of the tree before returning. Or, if an
** error occurs, an SQLite error code is returned and the final value
** of *ppOut is undefined.
*/
static int vdbeSorterMergeTreeBuild(
  VdbeSorter *pSorter,       /* The VDBE cursor that implements the sort */
  MergeEngine **ppOut        /* Write the MergeEngine here */
){
  MergeEngine *pMain = 0;
  int rc = SQLITE_OK;
  int iTask;

#if SQLITE_MAX_WORKER_THREADS>0
  /* If the sorter uses more than one task, then create the top-level
  ** MergeEngine here. This MergeEngine will read data from exactly
  ** one PmaReader per sub-task.  */
  assert( pSorter->bUseThreads || pSorter->nTask==1 );
  if( pSorter->nTask>1 ){
    pMain = vdbeMergeEngineNew(pSorter->nTask);
    if( pMain==0 ) rc = SQLITE_NOMEM_BKPT;
  }
#endif

  for(iTask=0; rc==SQLITE_OK && iTask<pSorter->nTask; iTask++){
    SortSubtask *pTask = &pSorter->aTask[iTask];
    assert( pTask->nPMA>0 || SQLITE_MAX_WORKER_THREADS>0 );
    if( SQLITE_MAX_WORKER_THREADS==0 || pTask->nPMA ){
      MergeEngine *pRoot = 0;     /* Root node of tree for this task */
      int nDepth = vdbeSorterTreeDepth(pTask->nPMA);
      i64 iReadOff = 0;

      if( pTask->nPMA<=SORTER_MAX_MERGE_COUNT ){
        rc = vdbeMergeEngineLevel0(pTask, pTask->nPMA, &iReadOff, &pRoot);
      }else{
        int i;
        int iSeq = 0;
        pRoot = vdbeMergeEngineNew(SORTER_MAX_MERGE_COUNT);
        if( pRoot==0 ) rc = SQLITE_NOMEM_BKPT;
        for(i=0; i<pTask->nPMA && rc==SQLITE_OK; i += SORTER_MAX_MERGE_COUNT){
          MergeEngine *pMerger = 0; /* New level-0 PMA merger */
          int nReader;              /* Number of level-0 PMAs to merge */

          nReader = MIN(pTask->nPMA - i, SORTER_MAX_MERGE_COUNT);
          rc = vdbeMergeEngineLevel0(pTask, nReader, &iReadOff, &pMerger);
          if( rc==SQLITE_OK ){
            rc = vdbeSorterAddToTree(pTask, nDepth, iSeq++, pRoot, pMerger);
          }
        }
      }

      if( rc==SQLITE_OK ){
#if SQLITE_MAX_WORKER_THREADS>0
        if( pMain!=0 ){
          rc = vdbeIncrMergerNew(pTask, pRoot, &pMain->aReadr[iTask].pIncr);
        }else
#endif
        {
          assert( pMain==0 );
          pMain = pRoot;
        }
      }else{
        vdbeMergeEngineFree(pRoot);
      }
    }
  }

sqlite3.c  view on Meta::CPAN

    }
  }else{
    SorterRecord *pFree = pSorter->list.pList;
    pSorter->list.pList = pFree->u.pNext;
    pFree->u.pNext = 0;
    if( pSorter->list.aMemory==0 ) vdbeSorterRecordFree(db, pFree);
    rc = pSorter->list.pList ? SQLITE_OK : SQLITE_DONE;
  }
  return rc;
}

/*
** Return a pointer to a buffer owned by the sorter that contains the
** current key.
*/
static void *vdbeSorterRowkey(
  const VdbeSorter *pSorter,      /* Sorter object */
  int *pnKey                      /* OUT: Size of current key in bytes */
){
  void *pKey;
  if( pSorter->bUsePMA ){
    PmaReader *pReader;
#if SQLITE_MAX_WORKER_THREADS>0
    if( pSorter->bUseThreads ){
      pReader = pSorter->pReader;
    }else
#endif
    /*if( !pSorter->bUseThreads )*/{
      pReader = &pSorter->pMerger->aReadr[pSorter->pMerger->aTree[1]];
    }
    *pnKey = pReader->nKey;
    pKey = pReader->aKey;
  }else{
    *pnKey = pSorter->list.pList->nVal;
    pKey = SRVAL(pSorter->list.pList);
  }
  return pKey;
}

/*
** Copy the current sorter key into the memory cell pOut.
*/
SQLITE_PRIVATE int sqlite3VdbeSorterRowkey(const VdbeCursor *pCsr, Mem *pOut){
  VdbeSorter *pSorter;
  void *pKey; int nKey;           /* Sorter key to copy into pOut */

  assert( pCsr->eCurType==CURTYPE_SORTER );
  pSorter = pCsr->uc.pSorter;
  pKey = vdbeSorterRowkey(pSorter, &nKey);
  if( sqlite3VdbeMemClearAndResize(pOut, nKey) ){
    return SQLITE_NOMEM_BKPT;
  }
  pOut->n = nKey;
  MemSetTypeFlag(pOut, MEM_Blob);
  memcpy(pOut->z, pKey, nKey);

  return SQLITE_OK;
}

/*
** Compare the key in memory cell pVal with the key that the sorter cursor
** passed as the first argument currently points to. For the purposes of
** the comparison, ignore the rowid field at the end of each record.
**
** If the sorter cursor key contains any NULL values, consider it to be
** less than pVal. Even if pVal also contains NULL values.
**
** If an error occurs, return an SQLite error code (i.e. SQLITE_NOMEM).
** Otherwise, set *pRes to a negative, zero or positive value if the
** key in pVal is smaller than, equal to or larger than the current sorter
** key.
**
** This routine forms the core of the OP_SorterCompare opcode, which in
** turn is used to verify uniqueness when constructing a UNIQUE INDEX.
*/
SQLITE_PRIVATE int sqlite3VdbeSorterCompare(
  const VdbeCursor *pCsr,         /* Sorter cursor */
  Mem *pVal,                      /* Value to compare to current sorter key */
  int nKeyCol,                    /* Compare this many columns */
  int *pRes                       /* OUT: Result of comparison */
){
  VdbeSorter *pSorter;
  UnpackedRecord *r2;
  KeyInfo *pKeyInfo;
  int i;
  void *pKey; int nKey;           /* Sorter key to compare pVal with */

  assert( pCsr->eCurType==CURTYPE_SORTER );
  pSorter = pCsr->uc.pSorter;
  r2 = pSorter->pUnpacked;
  pKeyInfo = pCsr->pKeyInfo;
  if( r2==0 ){
    r2 = pSorter->pUnpacked = sqlite3VdbeAllocUnpackedRecord(pKeyInfo);
    if( r2==0 ) return SQLITE_NOMEM_BKPT;
    r2->nField = nKeyCol;
  }
  assert( r2->nField==nKeyCol );

  pKey = vdbeSorterRowkey(pSorter, &nKey);
  sqlite3VdbeRecordUnpack(nKey, pKey, r2);
  for(i=0; i<nKeyCol; i++){
    if( r2->aMem[i].flags & MEM_Null ){
      *pRes = -1;
      return SQLITE_OK;
    }
  }

  *pRes = sqlite3VdbeRecordCompare(pVal->n, pVal->z, r2);
  return SQLITE_OK;
}

/************** End of vdbesort.c ********************************************/
/************** Begin file vdbevtab.c ****************************************/
/*
** 2020-03-23
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file implements virtual-tables for examining the bytecode content
** of a prepared statement.
*/
/* #include "sqliteInt.h" */
#if defined(SQLITE_ENABLE_BYTECODE_VTAB) && !defined(SQLITE_OMIT_VIRTUALTABLE)
/* #include "vdbeInt.h" */

/* An instance of the bytecode() table-valued function.
*/
typedef struct bytecodevtab bytecodevtab;
struct bytecodevtab {
  sqlite3_vtab base;     /* Base class - must be first */
  sqlite3 *db;           /* Database connection */
  int bTablesUsed;       /* 2 for tables_used().  0 for bytecode(). */
};

/* A cursor for scanning through the bytecode
*/
typedef struct bytecodevtab_cursor bytecodevtab_cursor;
struct bytecodevtab_cursor {
  sqlite3_vtab_cursor base;  /* Base class - must be first */
  sqlite3_stmt *pStmt;       /* The statement whose bytecode is displayed */
  int iRowid;                /* The rowid of the output table */
  int iAddr;                 /* Address */
  int needFinalize;          /* Cursors owns pStmt and must finalize it */
  int showSubprograms;       /* Provide a listing of subprograms */
  Op *aOp;                   /* Operand array */
  char *zP4;                 /* Rendered P4 value */
  const char *zType;         /* tables_used.type */
  const char *zSchema;       /* tables_used.schema */
  const char *zName;         /* tables_used.name */
  Mem sub;                   /* Subprograms */
};

/*
** Create a new bytecode() table-valued function.
*/
static int bytecodevtabConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  bytecodevtab *pNew;
  int rc;
  int isTabUsed = pAux!=0;
  const char *azSchema[2] = {
    /* bytecode() schema */
    "CREATE TABLE x("
      "addr INT,"
      "opcode TEXT,"
      "p1 INT,"
      "p2 INT,"
      "p3 INT,"
      "p4 TEXT,"
      "p5 INT,"
      "comment TEXT,"
      "subprog TEXT,"
      "nexec INT,"
      "ncycle INT,"
      "stmt HIDDEN"
    ");",

    /* Tables_used() schema */
    "CREATE TABLE x("
      "type TEXT,"
      "schema TEXT,"
      "name TEXT,"
      "wr INT,"
      "subprog TEXT,"
      "stmt HIDDEN"
   ");"
  };

  (void)argc;
  (void)argv;
  (void)pzErr;
  rc = sqlite3_declare_vtab(db, azSchema[isTabUsed]);
  if( rc==SQLITE_OK ){
    pNew = sqlite3_malloc( sizeof(*pNew) );
    *ppVtab = (sqlite3_vtab*)pNew;
    if( pNew==0 ) return SQLITE_NOMEM;
    memset(pNew, 0, sizeof(*pNew));
    pNew->db = db;
    pNew->bTablesUsed = isTabUsed*2;
  }
  return rc;
}

/*
** This method is the destructor for bytecodevtab objects.
*/
static int bytecodevtabDisconnect(sqlite3_vtab *pVtab){
  bytecodevtab *p = (bytecodevtab*)pVtab;
  sqlite3_free(p);
  return SQLITE_OK;
}

/*
** Constructor for a new bytecodevtab_cursor object.
*/
static int bytecodevtabOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
  bytecodevtab *pVTab = (bytecodevtab*)p;
  bytecodevtab_cursor *pCur;
  pCur = sqlite3_malloc( sizeof(*pCur) );
  if( pCur==0 ) return SQLITE_NOMEM;
  memset(pCur, 0, sizeof(*pCur));
  sqlite3VdbeMemInit(&pCur->sub, pVTab->db, 1);
  *ppCursor = &pCur->base;
  return SQLITE_OK;
}

/*
** Clear all internal content from a bytecodevtab cursor.
*/
static void bytecodevtabCursorClear(bytecodevtab_cursor *pCur){
  sqlite3_free(pCur->zP4);
  pCur->zP4 = 0;
  sqlite3VdbeMemRelease(&pCur->sub);
  sqlite3VdbeMemSetNull(&pCur->sub);
  if( pCur->needFinalize ){
    sqlite3_finalize(pCur->pStmt);
  }
  pCur->pStmt = 0;
  pCur->needFinalize = 0;
  pCur->zType = 0;
  pCur->zSchema = 0;
  pCur->zName = 0;
}

/*
** Destructor for a bytecodevtab_cursor.
*/
static int bytecodevtabClose(sqlite3_vtab_cursor *cur){
  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
  bytecodevtabCursorClear(pCur);
  sqlite3_free(pCur);
  return SQLITE_OK;
}


/*
** Advance a bytecodevtab_cursor to its next row of output.
*/
static int bytecodevtabNext(sqlite3_vtab_cursor *cur){
  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
  bytecodevtab *pTab = (bytecodevtab*)cur->pVtab;
  int rc;
  if( pCur->zP4 ){
    sqlite3_free(pCur->zP4);
    pCur->zP4 = 0;
  }
  if( pCur->zName ){
    pCur->zName = 0;
    pCur->zType = 0;
    pCur->zSchema = 0;
  }
  rc = sqlite3VdbeNextOpcode(
           (Vdbe*)pCur->pStmt,
           pCur->showSubprograms ? &pCur->sub : 0,
           pTab->bTablesUsed,
           &pCur->iRowid,
           &pCur->iAddr,
           &pCur->aOp);
  if( rc!=SQLITE_OK ){
    sqlite3VdbeMemSetNull(&pCur->sub);
    pCur->aOp = 0;
  }
  return SQLITE_OK;
}

/*
** Return TRUE if the cursor has been moved off of the last
** row of output.
*/
static int bytecodevtabEof(sqlite3_vtab_cursor *cur){
  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
  return pCur->aOp==0;
}

/*
** Return values of columns for the row at which the bytecodevtab_cursor
** is currently pointing.
*/
static int bytecodevtabColumn(
  sqlite3_vtab_cursor *cur,   /* The cursor */
  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
  int i                       /* Which column to return */
){
  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
  bytecodevtab *pVTab = (bytecodevtab*)cur->pVtab;
  Op *pOp = pCur->aOp + pCur->iAddr;
  if( pVTab->bTablesUsed ){
    if( i==4 ){
      i = 8;
    }else{
      if( i<=2 && pCur->zType==0 ){
        Schema *pSchema;
        HashElem *k;
        int iDb = pOp->p3;
        Pgno iRoot = (Pgno)pOp->p2;
        sqlite3 *db = pVTab->db;
        pSchema = db->aDb[iDb].pSchema;
        pCur->zSchema = db->aDb[iDb].zDbSName;
        for(k=sqliteHashFirst(&pSchema->tblHash); k; k=sqliteHashNext(k)){
          Table *pTab = (Table*)sqliteHashData(k);
          if( !IsVirtual(pTab) && pTab->tnum==iRoot ){
            pCur->zName = pTab->zName;
            pCur->zType = "table";
            break;
          }
        }
        if( pCur->zName==0 ){
          for(k=sqliteHashFirst(&pSchema->idxHash); k; k=sqliteHashNext(k)){
            Index *pIdx = (Index*)sqliteHashData(k);
            if( pIdx->tnum==iRoot ){
              pCur->zName = pIdx->zName;
              pCur->zType = "index";
            }
          }
        }
      }
      i += 20;
    }
  }
  switch( i ){
    case 0:   /* addr */
      sqlite3_result_int(ctx, pCur->iAddr);
      break;
    case 1:   /* opcode */
      sqlite3_result_text(ctx, (char*)sqlite3OpcodeName(pOp->opcode),
                          -1, SQLITE_STATIC);
      break;
    case 2:   /* p1 */
      sqlite3_result_int(ctx, pOp->p1);
      break;
    case 3:   /* p2 */
      sqlite3_result_int(ctx, pOp->p2);
      break;
    case 4:   /* p3 */
      sqlite3_result_int(ctx, pOp->p3);
      break;
    case 5:   /* p4 */
    case 7:   /* comment */
      if( pCur->zP4==0 ){
        pCur->zP4 = sqlite3VdbeDisplayP4(pVTab->db, pOp);
      }
      if( i==5 ){
        sqlite3_result_text(ctx, pCur->zP4, -1, SQLITE_STATIC);
      }else{
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
        char *zCom = sqlite3VdbeDisplayComment(pVTab->db, pOp, pCur->zP4);
        sqlite3_result_text(ctx, zCom, -1, sqlite3_free);
#endif
      }
      break;
    case 6:     /* p5 */
      sqlite3_result_int(ctx, pOp->p5);
      break;
    case 8: {   /* subprog */
      Op *aOp = pCur->aOp;
      assert( aOp[0].opcode==OP_Init );
      assert( aOp[0].p4.z==0 || strncmp(aOp[0].p4.z,"-" "- ",3)==0 );
      if( pCur->iRowid==pCur->iAddr+1 ){
        break;  /* Result is NULL for the main program */
      }else if( aOp[0].p4.z!=0 ){
         sqlite3_result_text(ctx, aOp[0].p4.z+3, -1, SQLITE_STATIC);
      }else{
         sqlite3_result_text(ctx, "(FK)", 4, SQLITE_STATIC);
      }
      break;
    }

#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
    case 9:     /* nexec */
      sqlite3_result_int64(ctx, pOp->nExec);
      break;
    case 10:    /* ncycle */
      sqlite3_result_int64(ctx, pOp->nCycle);
      break;
#else
    case 9:     /* nexec */
    case 10:    /* ncycle */
      sqlite3_result_int(ctx, 0);
      break;
#endif

    case 20:  /* tables_used.type */
      sqlite3_result_text(ctx, pCur->zType, -1, SQLITE_STATIC);
      break;
    case 21:  /* tables_used.schema */
      sqlite3_result_text(ctx, pCur->zSchema, -1, SQLITE_STATIC);
      break;
    case 22:  /* tables_used.name */
      sqlite3_result_text(ctx, pCur->zName, -1, SQLITE_STATIC);
      break;
    case 23:  /* tables_used.wr */
      sqlite3_result_int(ctx, pOp->opcode==OP_OpenWrite);
      break;
  }
  return SQLITE_OK;
}

/*
** Return the rowid for the current row.  In this implementation, the
** rowid is the same as the output value.
*/
static int bytecodevtabRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  bytecodevtab_cursor *pCur = (bytecodevtab_cursor*)cur;
  *pRowid = pCur->iRowid;
  return SQLITE_OK;
}

/*
** Initialize a cursor.
**
**    idxNum==0     means show all subprograms
**    idxNum==1     means show only the main bytecode and omit subprograms.
*/
static int bytecodevtabFilter(
  sqlite3_vtab_cursor *pVtabCursor,
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  bytecodevtab_cursor *pCur = (bytecodevtab_cursor *)pVtabCursor;
  bytecodevtab *pVTab = (bytecodevtab *)pVtabCursor->pVtab;
  int rc = SQLITE_OK;
  (void)idxStr;

  bytecodevtabCursorClear(pCur);
  pCur->iRowid = 0;
  pCur->iAddr = 0;
  pCur->showSubprograms = idxNum==0;
  assert( argc==1 );
  if( sqlite3_value_type(argv[0])==SQLITE_TEXT ){
    const char *zSql = (const char*)sqlite3_value_text(argv[0]);
    if( zSql==0 ){
      rc = SQLITE_NOMEM;
    }else{
      rc = sqlite3_prepare_v2(pVTab->db, zSql, -1, &pCur->pStmt, 0);
      pCur->needFinalize = 1;
    }
  }else{
    pCur->pStmt = (sqlite3_stmt*)sqlite3_value_pointer(argv[0],"stmt-pointer");
  }
  if( pCur->pStmt==0 ){
    pVTab->base.zErrMsg = sqlite3_mprintf(
       "argument to %s() is not a valid SQL statement",
       pVTab->bTablesUsed ? "tables_used" : "bytecode"
    );
    rc = SQLITE_ERROR;
  }else{
    bytecodevtabNext(pVtabCursor);
  }
  return rc;
}

/*
** We must have a single stmt=? constraint that will be passed through
** into the xFilter method.  If there is no valid stmt=? constraint,
** then return an SQLITE_CONSTRAINT error.
*/
static int bytecodevtabBestIndex(
  sqlite3_vtab *tab,
  sqlite3_index_info *pIdxInfo
){
  int i;
  int rc = SQLITE_CONSTRAINT;
  struct sqlite3_index_constraint *p;
  bytecodevtab *pVTab = (bytecodevtab*)tab;
  int iBaseCol = pVTab->bTablesUsed ? 4 : 10;
  pIdxInfo->estimatedCost = (double)100;
  pIdxInfo->estimatedRows = 100;
  pIdxInfo->idxNum = 0;
  for(i=0, p=pIdxInfo->aConstraint; i<pIdxInfo->nConstraint; i++, p++){
    if( p->usable==0 ) continue;
    if( p->op==SQLITE_INDEX_CONSTRAINT_EQ && p->iColumn==iBaseCol+1 ){
      rc = SQLITE_OK;
      pIdxInfo->aConstraintUsage[i].omit = 1;
      pIdxInfo->aConstraintUsage[i].argvIndex = 1;
    }
    if( p->op==SQLITE_INDEX_CONSTRAINT_ISNULL && p->iColumn==iBaseCol ){
      pIdxInfo->aConstraintUsage[i].omit = 1;
      pIdxInfo->idxNum = 1;
    }

sqlite3.c  view on Meta::CPAN

SQLITE_PRIVATE int sqlite3VdbeBytecodeVtabInit(sqlite3 *db){ return SQLITE_OK; }
#endif /* SQLITE_ENABLE_BYTECODE_VTAB */

/************** End of vdbevtab.c ********************************************/
/************** Begin file memjournal.c **************************************/
/*
** 2008 October 7
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file contains code use to implement an in-memory rollback journal.
** The in-memory rollback journal is used to journal transactions for
** ":memory:" databases and when the journal_mode=MEMORY pragma is used.
**
** Update:  The in-memory journal is also used to temporarily cache
** smaller journals that are not critical for power-loss recovery.
** For example, statement journals that are not too big will be held
** entirely in memory, thus reducing the number of file I/O calls, and
** more importantly, reducing temporary file creation events.  If these
** journals become too large for memory, they are spilled to disk.  But
** in the common case, they are usually small and no file I/O needs to
** occur.
*/
/* #include "sqliteInt.h" */

/* Forward references to internal structures */
typedef struct MemJournal MemJournal;
typedef struct FilePoint FilePoint;
typedef struct FileChunk FileChunk;

/*
** The rollback journal is composed of a linked list of these structures.
**
** The zChunk array is always at least 8 bytes in size - usually much more.
** Its actual size is stored in the MemJournal.nChunkSize variable.
*/
struct FileChunk {
  FileChunk *pNext;               /* Next chunk in the journal */
  u8 zChunk[8];                   /* Content of this chunk */
};

/*
** By default, allocate this many bytes of memory for each FileChunk object.
*/
#define MEMJOURNAL_DFLT_FILECHUNKSIZE 1024

/*
** For chunk size nChunkSize, return the number of bytes that should
** be allocated for each FileChunk structure.
*/
#define fileChunkSize(nChunkSize) (sizeof(FileChunk) + ((nChunkSize)-8))

/*
** An instance of this object serves as a cursor into the rollback journal.
** The cursor can be either for reading or writing.
*/
struct FilePoint {
  sqlite3_int64 iOffset;          /* Offset from the beginning of the file */
  FileChunk *pChunk;              /* Specific chunk into which cursor points */
};

/*
** This structure is a subclass of sqlite3_file. Each open memory-journal
** is an instance of this class.
*/
struct MemJournal {
  const sqlite3_io_methods *pMethod; /* Parent class. MUST BE FIRST */
  int nChunkSize;                 /* In-memory chunk-size */

  int nSpill;                     /* Bytes of data before flushing */
  FileChunk *pFirst;              /* Head of in-memory chunk-list */
  FilePoint endpoint;             /* Pointer to the end of the file */
  FilePoint readpoint;            /* Pointer to the end of the last xRead() */

  int flags;                      /* xOpen flags */
  sqlite3_vfs *pVfs;              /* The "real" underlying VFS */
  const char *zJournal;           /* Name of the journal file */
};

/*
** Read data from the in-memory journal file.  This is the implementation
** of the sqlite3_vfs.xRead method.
*/
static int memjrnlRead(
  sqlite3_file *pJfd,    /* The journal file from which to read */
  void *zBuf,            /* Put the results here */
  int iAmt,              /* Number of bytes to read */
  sqlite_int64 iOfst     /* Begin reading at this offset */
){
  MemJournal *p = (MemJournal *)pJfd;
  u8 *zOut = zBuf;
  int nRead = iAmt;
  int iChunkOffset;
  FileChunk *pChunk;

  if( (iAmt+iOfst)>p->endpoint.iOffset ){
    return SQLITE_IOERR_SHORT_READ;
  }
  assert( p->readpoint.iOffset==0 || p->readpoint.pChunk!=0 );
  if( p->readpoint.iOffset!=iOfst || iOfst==0 ){
    sqlite3_int64 iOff = 0;
    for(pChunk=p->pFirst;
        ALWAYS(pChunk) && (iOff+p->nChunkSize)<=iOfst;
        pChunk=pChunk->pNext
    ){
      iOff += p->nChunkSize;
    }
  }else{
    pChunk = p->readpoint.pChunk;
    assert( pChunk!=0 );
  }

  iChunkOffset = (int)(iOfst%p->nChunkSize);
  do {
    int iSpace = p->nChunkSize - iChunkOffset;
    int nCopy = MIN(nRead, (p->nChunkSize - iChunkOffset));
    memcpy(zOut, (u8*)pChunk->zChunk + iChunkOffset, nCopy);
    zOut += nCopy;
    nRead -= iSpace;

sqlite3.c  view on Meta::CPAN

  }
}

/*
** Create a new expression term for the column specified by pMatch and
** iColumn.  Append this new expression term to the FULL JOIN Match set
** in *ppList.  Create a new *ppList if this is the first term in the
** set.
*/
static void extendFJMatch(
  Parse *pParse,          /* Parsing context */
  ExprList **ppList,      /* ExprList to extend */
  SrcItem *pMatch,        /* Source table containing the column */
  i16 iColumn             /* The column number */
){
  Expr *pNew = sqlite3ExprAlloc(pParse->db, TK_COLUMN, 0, 0);
  if( pNew ){
    pNew->iTable = pMatch->iCursor;
    pNew->iColumn = iColumn;
    pNew->y.pTab = pMatch->pSTab;
    assert( (pMatch->fg.jointype & (JT_LEFT|JT_LTORJ))!=0 );
    ExprSetProperty(pNew, EP_CanBeNull);
    *ppList = sqlite3ExprListAppend(pParse, *ppList, pNew);
  }
}

/*
** Return TRUE (non-zero) if zTab is a valid name for the schema table pTab.
*/
static SQLITE_NOINLINE int isValidSchemaTableName(
  const char *zTab,         /* Name as it appears in the SQL */
  Table *pTab,              /* The schema table we are trying to match */
  const char *zDb           /* non-NULL if a database qualifier is present */
){
  const char *zLegacy;
  assert( pTab!=0 );
  assert( pTab->tnum==1 );
  if( sqlite3StrNICmp(zTab, "sqlite_", 7)!=0 ) return 0;
  zLegacy = pTab->zName;
  if( strcmp(zLegacy+7, &LEGACY_TEMP_SCHEMA_TABLE[7])==0 ){
    if( sqlite3StrICmp(zTab+7, &PREFERRED_TEMP_SCHEMA_TABLE[7])==0 ){
      return 1;
    }
    if( zDb==0 ) return 0;
    if( sqlite3StrICmp(zTab+7, &LEGACY_SCHEMA_TABLE[7])==0 ) return 1;
    if( sqlite3StrICmp(zTab+7, &PREFERRED_SCHEMA_TABLE[7])==0 ) return 1;
  }else{
    if( sqlite3StrICmp(zTab+7, &PREFERRED_SCHEMA_TABLE[7])==0 ) return 1;
  }
  return 0;
}

/*
** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up
** that name in the set of source tables in pSrcList and make the pExpr
** expression node refer back to that source column.  The following changes
** are made to pExpr:
**
**    pExpr->iDb           Set the index in db->aDb[] of the database X
**                         (even if X is implied).
**    pExpr->iTable        Set to the cursor number for the table obtained
**                         from pSrcList.
**    pExpr->y.pTab        Points to the Table structure of X.Y (even if
**                         X and/or Y are implied.)
**    pExpr->iColumn       Set to the column number within the table.
**    pExpr->op            Set to TK_COLUMN.
**    pExpr->pLeft         Any expression this points to is deleted
**    pExpr->pRight        Any expression this points to is deleted.
**
** The zDb variable is the name of the database (the "X").  This value may be
** NULL meaning that name is of the form Y.Z or Z.  Any available database
** can be used.  The zTable variable is the name of the table (the "Y").  This
** value can be NULL if zDb is also NULL.  If zTable is NULL it
** means that the form of the name is Z and that columns from any table
** can be used.
**
** If the name cannot be resolved unambiguously, leave an error message
** in pParse and return WRC_Abort.  Return WRC_Prune on success.
*/
static int lookupName(
  Parse *pParse,       /* The parsing context */
  const char *zDb,     /* Name of the database containing table, or NULL */
  const char *zTab,    /* Name of table containing column, or NULL */
  const Expr *pRight,  /* Name of the column. */
  NameContext *pNC,    /* The name context used to resolve the name */
  Expr *pExpr          /* Make this EXPR node point to the selected column */
){
  int i, j;                         /* Loop counters */
  int cnt = 0;                      /* Number of matching column names */
  int cntTab = 0;                   /* Number of potential "rowid" matches */
  int nSubquery = 0;                /* How many levels of subquery */
  sqlite3 *db = pParse->db;         /* The database connection */
  SrcItem *pItem;                   /* Use for looping over pSrcList items */
  SrcItem *pMatch = 0;              /* The matching pSrcList item */
  NameContext *pTopNC = pNC;        /* First namecontext in the list */
  Schema *pSchema = 0;              /* Schema of the expression */
  int eNewExprOp = TK_COLUMN;       /* New value for pExpr->op on success */
  Table *pTab = 0;                  /* Table holding the row */
  ExprList *pFJMatch = 0;           /* Matches for FULL JOIN .. USING */
  const char *zCol = pRight->u.zToken;

  assert( pNC );     /* the name context cannot be NULL. */
  assert( zCol );    /* The Z in X.Y.Z cannot be NULL */
  assert( zDb==0 || zTab!=0 );
  assert( !ExprHasProperty(pExpr, EP_TokenOnly|EP_Reduced) );

  /* Initialize the node to no-match */
  pExpr->iTable = -1;
  ExprSetVVAProperty(pExpr, EP_NoReduce);

  /* Translate the schema name in zDb into a pointer to the corresponding
  ** schema.  If not found, pSchema will remain NULL and nothing will match
  ** resulting in an appropriate error message toward the end of this routine
  */
  if( zDb ){
    testcase( pNC->ncFlags & NC_PartIdx );
    testcase( pNC->ncFlags & NC_IsCheck );
    if( (pNC->ncFlags & (NC_PartIdx|NC_IsCheck))!=0 ){
      /* Silently ignore database qualifiers inside CHECK constraints and
      ** partial indices.  Do not raise errors because that might break
      ** legacy and because it does not hurt anything to just ignore the

sqlite3.c  view on Meta::CPAN

    if( pGroupBy ){
      struct ExprList_item *pItem;

      if( resolveOrderGroupBy(&sNC, p, pGroupBy, "GROUP") || db->mallocFailed ){
        return WRC_Abort;
      }
      for(i=0, pItem=pGroupBy->a; i<pGroupBy->nExpr; i++, pItem++){
        if( ExprHasProperty(pItem->pExpr, EP_Agg) ){
          sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in "
              "the GROUP BY clause");
          return WRC_Abort;
        }
      }
    }

    /* If this is part of a compound SELECT, check that it has the right
    ** number of expressions in the select list. */
    if( p->pNext && p->pEList->nExpr!=p->pNext->pEList->nExpr ){
      sqlite3SelectWrongNumTermsError(pParse, p->pNext);
      return WRC_Abort;
    }

    /* Advance to the next term of the compound
    */
    p = p->pPrior;
    nCompound++;
  }

  /* Resolve the ORDER BY on a compound SELECT after all terms of
  ** the compound have been resolved.
  */
  if( isCompound && resolveCompoundOrderBy(pParse, pLeftmost) ){
    return WRC_Abort;
  }

  return WRC_Prune;
}

/*
** This routine walks an expression tree and resolves references to
** table columns and result-set columns.  At the same time, do error
** checking on function usage and set a flag if any aggregate functions
** are seen.
**
** To resolve table columns references we look for nodes (or subtrees) of the
** form X.Y.Z or Y.Z or just Z where
**
**      X:   The name of a database.  Ex:  "main" or "temp" or
**           the symbolic name assigned to an ATTACH-ed database.
**
**      Y:   The name of a table in a FROM clause.  Or in a trigger
**           one of the special names "old" or "new".
**
**      Z:   The name of a column in table Y.
**
** The node at the root of the subtree is modified as follows:
**
**    Expr.op        Changed to TK_COLUMN
**    Expr.pTab      Points to the Table object for X.Y
**    Expr.iColumn   The column index in X.Y.  -1 for the rowid.
**    Expr.iTable    The VDBE cursor number for X.Y
**
**
** To resolve result-set references, look for expression nodes of the
** form Z (with no X and Y prefix) where the Z matches the right-hand
** size of an AS clause in the result-set of a SELECT.  The Z expression
** is replaced by a copy of the left-hand side of the result-set expression.
** Table-name and function resolution occurs on the substituted expression
** tree.  For example, in:
**
**      SELECT a+b AS x, c+d AS y FROM t1 ORDER BY x;
**
** The "x" term of the order by is replaced by "a+b" to render:
**
**      SELECT a+b AS x, c+d AS y FROM t1 ORDER BY a+b;
**
** Function calls are checked to make sure that the function is
** defined and that the correct number of arguments are specified.
** If the function is an aggregate function, then the NC_HasAgg flag is
** set and the opcode is changed from TK_FUNCTION to TK_AGG_FUNCTION.
** If an expression contains aggregate functions then the EP_Agg
** property on the expression is set.
**
** An error message is left in pParse if anything is amiss.  The number
** if errors is returned.
*/
SQLITE_PRIVATE int sqlite3ResolveExprNames(
  NameContext *pNC,       /* Namespace to resolve expressions in. */
  Expr *pExpr             /* The expression to be analyzed. */
){
  int savedHasAgg;
  Walker w;

  if( pExpr==0 ) return SQLITE_OK;
  savedHasAgg = pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
  pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin|NC_OrderAgg);
  w.pParse = pNC->pParse;
  w.xExprCallback = resolveExprStep;
  w.xSelectCallback = (pNC->ncFlags & NC_NoSelect) ? 0 : resolveSelectStep;
  w.xSelectCallback2 = 0;
  w.u.pNC = pNC;
#if SQLITE_MAX_EXPR_DEPTH>0
  w.pParse->nHeight += pExpr->nHeight;
  if( sqlite3ExprCheckHeight(w.pParse, w.pParse->nHeight) ){
    return SQLITE_ERROR;
  }
#endif
  assert( pExpr!=0 );
  sqlite3WalkExprNN(&w, pExpr);
#if SQLITE_MAX_EXPR_DEPTH>0
  w.pParse->nHeight -= pExpr->nHeight;
#endif
  assert( EP_Agg==NC_HasAgg );
  assert( EP_Win==NC_HasWin );
  testcase( pNC->ncFlags & NC_HasAgg );
  testcase( pNC->ncFlags & NC_HasWin );
  ExprSetProperty(pExpr, pNC->ncFlags & (NC_HasAgg|NC_HasWin) );
  pNC->ncFlags |= savedHasAgg;
  return pNC->nNcErr>0 || w.pParse->nErr>0;
}

sqlite3.c  view on Meta::CPAN

  CollSeq *p4;

  if( pParse->nErr ) return 0;
  if( isCommuted ){
    p4 = sqlite3BinaryCompareCollSeq(pParse, pRight, pLeft);
  }else{
    p4 = sqlite3BinaryCompareCollSeq(pParse, pLeft, pRight);
  }
  p5 = binaryCompareP5(pLeft, pRight, jumpIfNull);
  addr = sqlite3VdbeAddOp4(pParse->pVdbe, opcode, in2, dest, in1,
                           (void*)p4, P4_COLLSEQ);
  sqlite3VdbeChangeP5(pParse->pVdbe, (u16)p5);
  return addr;
}

/*
** Return true if expression pExpr is a vector, or false otherwise.
**
** A vector is defined as any expression that results in two or more
** columns of result.  Every TK_VECTOR node is an vector because the
** parser will not generate a TK_VECTOR with fewer than two entries.
** But a TK_SELECT might be either a vector or a scalar. It is only
** considered a vector if it has two or more result columns.
*/
SQLITE_PRIVATE int sqlite3ExprIsVector(const Expr *pExpr){
  return sqlite3ExprVectorSize(pExpr)>1;
}

/*
** If the expression passed as the only argument is of type TK_VECTOR
** return the number of expressions in the vector. Or, if the expression
** is a sub-select, return the number of columns in the sub-select. For
** any other type of expression, return 1.
*/
SQLITE_PRIVATE int sqlite3ExprVectorSize(const Expr *pExpr){
  u8 op = pExpr->op;
  if( op==TK_REGISTER ) op = pExpr->op2;
  if( op==TK_VECTOR ){
    assert( ExprUseXList(pExpr) );
    return pExpr->x.pList->nExpr;
  }else if( op==TK_SELECT ){
    assert( ExprUseXSelect(pExpr) );
    return pExpr->x.pSelect->pEList->nExpr;
  }else{
    return 1;
  }
}

/*
** Return a pointer to a subexpression of pVector that is the i-th
** column of the vector (numbered starting with 0).  The caller must
** ensure that i is within range.
**
** If pVector is really a scalar (and "scalar" here includes subqueries
** that return a single column!) then return pVector unmodified.
**
** pVector retains ownership of the returned subexpression.
**
** If the vector is a (SELECT ...) then the expression returned is
** just the expression for the i-th term of the result set, and may
** not be ready for evaluation because the table cursor has not yet
** been positioned.
*/
SQLITE_PRIVATE Expr *sqlite3VectorFieldSubexpr(Expr *pVector, int i){
  assert( i<sqlite3ExprVectorSize(pVector) || pVector->op==TK_ERROR );
  if( sqlite3ExprIsVector(pVector) ){
    assert( pVector->op2==0 || pVector->op==TK_REGISTER );
    if( pVector->op==TK_SELECT || pVector->op2==TK_SELECT ){
      assert( ExprUseXSelect(pVector) );
      return pVector->x.pSelect->pEList->a[i].pExpr;
    }else{
      assert( ExprUseXList(pVector) );
      return pVector->x.pList->a[i].pExpr;
    }
  }
  return pVector;
}

/*
** Compute and return a new Expr object which when passed to
** sqlite3ExprCode() will generate all necessary code to compute
** the iField-th column of the vector expression pVector.
**
** It is ok for pVector to be a scalar (as long as iField==0).
** In that case, this routine works like sqlite3ExprDup().
**
** The caller owns the returned Expr object and is responsible for
** ensuring that the returned value eventually gets freed.
**
** The caller retains ownership of pVector.  If pVector is a TK_SELECT,
** then the returned object will reference pVector and so pVector must remain
** valid for the life of the returned object.  If pVector is a TK_VECTOR
** or a scalar expression, then it can be deleted as soon as this routine
** returns.
**
** A trick to cause a TK_SELECT pVector to be deleted together with
** the returned Expr object is to attach the pVector to the pRight field
** of the returned TK_SELECT_COLUMN Expr object.
*/
SQLITE_PRIVATE Expr *sqlite3ExprForVectorField(
  Parse *pParse,       /* Parsing context */
  Expr *pVector,       /* The vector.  List of expressions or a sub-SELECT */
  int iField,          /* Which column of the vector to return */
  int nField           /* Total number of columns in the vector */
){
  Expr *pRet;
  if( pVector->op==TK_SELECT ){
    assert( ExprUseXSelect(pVector) );
    /* The TK_SELECT_COLUMN Expr node:
    **
    ** pLeft:           pVector containing TK_SELECT.  Not deleted.
    ** pRight:          not used.  But recursively deleted.
    ** iColumn:         Index of a column in pVector
    ** iTable:          0 or the number of columns on the LHS of an assignment
    ** pLeft->iTable:   First in an array of register holding result, or 0
    **                  if the result is not yet computed.
    **
    ** sqlite3ExprDelete() specifically skips the recursive delete of
    ** pLeft on TK_SELECT_COLUMN nodes.  But pRight is followed, so pVector
    ** can be attached to pRight to cause this node to take ownership of
    ** pVector.  Typically there will be multiple TK_SELECT_COLUMN nodes

sqlite3.c  view on Meta::CPAN

**
** The expression list, ID, and source lists return by sqlite3ExprListDup(),
** sqlite3IdListDup(), and sqlite3SrcListDup() can not be further expanded
** by subsequent calls to sqlite*ListAppend() routines.
**
** Any tables that the SrcList might point to are not duplicated.
**
** The flags parameter contains a combination of the EXPRDUP_XXX flags.
** If the EXPRDUP_REDUCE flag is set, then the structure returned is a
** truncated version of the usual Expr structure that will be stored as
** part of the in-memory representation of the database schema.
*/
SQLITE_PRIVATE Expr *sqlite3ExprDup(sqlite3 *db, const Expr *p, int flags){
  assert( flags==0 || flags==EXPRDUP_REDUCE );
  return p ? exprDup(db, p, flags, 0) : 0;
}
SQLITE_PRIVATE ExprList *sqlite3ExprListDup(sqlite3 *db, const ExprList *p, int flags){
  ExprList *pNew;
  struct ExprList_item *pItem;
  const struct ExprList_item *pOldItem;
  int i;
  Expr *pPriorSelectColOld = 0;
  Expr *pPriorSelectColNew = 0;
  assert( db!=0 );
  if( p==0 ) return 0;
  pNew = sqlite3DbMallocRawNN(db, sqlite3DbMallocSize(db, p));
  if( pNew==0 ) return 0;
  pNew->nExpr = p->nExpr;
  pNew->nAlloc = p->nAlloc;
  pItem = pNew->a;
  pOldItem = p->a;
  for(i=0; i<p->nExpr; i++, pItem++, pOldItem++){
    Expr *pOldExpr = pOldItem->pExpr;
    Expr *pNewExpr;
    pItem->pExpr = sqlite3ExprDup(db, pOldExpr, flags);
    if( pOldExpr
     && pOldExpr->op==TK_SELECT_COLUMN
     && (pNewExpr = pItem->pExpr)!=0
    ){
      if( pNewExpr->pRight ){
        pPriorSelectColOld = pOldExpr->pRight;
        pPriorSelectColNew = pNewExpr->pRight;
        pNewExpr->pLeft = pNewExpr->pRight;
      }else{
        if( pOldExpr->pLeft!=pPriorSelectColOld ){
          pPriorSelectColOld = pOldExpr->pLeft;
          pPriorSelectColNew = sqlite3ExprDup(db, pPriorSelectColOld, flags);
          pNewExpr->pRight = pPriorSelectColNew;
        }
        pNewExpr->pLeft = pPriorSelectColNew;
      }
    }
    pItem->zEName = sqlite3DbStrDup(db, pOldItem->zEName);
    pItem->fg = pOldItem->fg;
    pItem->u = pOldItem->u;
  }
  return pNew;
}

/*
** If cursors, triggers, views and subqueries are all omitted from
** the build, then none of the following routines, except for
** sqlite3SelectDup(), can be called. sqlite3SelectDup() is sometimes
** called with a NULL argument.
*/
#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER) \
 || !defined(SQLITE_OMIT_SUBQUERY)
SQLITE_PRIVATE SrcList *sqlite3SrcListDup(sqlite3 *db, const SrcList *p, int flags){
  SrcList *pNew;
  int i;
  assert( db!=0 );
  if( p==0 ) return 0;
  pNew = sqlite3DbMallocRawNN(db, SZ_SRCLIST(p->nSrc) );
  if( pNew==0 ) return 0;
  pNew->nSrc = pNew->nAlloc = p->nSrc;
  for(i=0; i<p->nSrc; i++){
    SrcItem *pNewItem = &pNew->a[i];
    const SrcItem *pOldItem = &p->a[i];
    Table *pTab;
    pNewItem->fg = pOldItem->fg;
    if( pOldItem->fg.isSubquery ){
      Subquery *pNewSubq = sqlite3DbMallocRaw(db, sizeof(Subquery));
      if( pNewSubq==0 ){
        assert( db->mallocFailed );
        pNewItem->fg.isSubquery = 0;
      }else{
        memcpy(pNewSubq, pOldItem->u4.pSubq, sizeof(*pNewSubq));
        pNewSubq->pSelect = sqlite3SelectDup(db, pNewSubq->pSelect, flags);
        if( pNewSubq->pSelect==0 ){
          sqlite3DbFree(db, pNewSubq);
          pNewSubq = 0;
          pNewItem->fg.isSubquery = 0;
        }
      }
      pNewItem->u4.pSubq = pNewSubq;
    }else if( pOldItem->fg.fixedSchema ){
      pNewItem->u4.pSchema = pOldItem->u4.pSchema;
    }else{
      pNewItem->u4.zDatabase = sqlite3DbStrDup(db, pOldItem->u4.zDatabase);
    }
    pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
    pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
    pNewItem->iCursor = pOldItem->iCursor;
    if( pNewItem->fg.isIndexedBy ){
      pNewItem->u1.zIndexedBy = sqlite3DbStrDup(db, pOldItem->u1.zIndexedBy);
    }else if( pNewItem->fg.isTabFunc ){
      pNewItem->u1.pFuncArg =
          sqlite3ExprListDup(db, pOldItem->u1.pFuncArg, flags);
    }else{
      pNewItem->u1.nRow = pOldItem->u1.nRow;
    }
    pNewItem->u2 = pOldItem->u2;
    if( pNewItem->fg.isCte ){
      pNewItem->u2.pCteUse->nUse++;
    }
    pTab = pNewItem->pSTab = pOldItem->pSTab;
    if( pTab ){
      pTab->nTabRef++;
    }
    if( pOldItem->fg.isUsing ){
      assert( pNewItem->fg.isUsing );

sqlite3.c  view on Meta::CPAN

#ifdef SQLITE_DEBUG
  w.xSelectCallback2 = sqlite3SelectWalkAssert2;
#endif
  sqlite3WalkExpr(&w, p);
  return w.eCode;
}

/*
** Walk an expression tree.  Return non-zero if the expression is constant
** and 0 if it involves variables or function calls.
**
** For the purposes of this function, a double-quoted string (ex: "abc")
** is considered a variable but a single-quoted string (ex: 'abc') is
** a constant.
**
** The pParse parameter may be NULL.  But if it is NULL, there is no way
** to determine if function calls are constant or not, and hence all
** function calls will be considered to be non-constant.  If pParse is
** not NULL, then a function call might be constant, depending on the
** function and on its parameters.
*/
SQLITE_PRIVATE int sqlite3ExprIsConstant(Parse *pParse, Expr *p){
  return exprIsConst(pParse, p, 1);
}

/*
** Walk an expression tree.  Return non-zero if
**
**   (1) the expression is constant, and
**   (2) the expression does originate in the ON or USING clause
**       of a LEFT JOIN, and
**   (3) the expression does not contain any EP_FixedCol TK_COLUMN
**       operands created by the constant propagation optimization.
**
** When this routine returns true, it indicates that the expression
** can be added to the pParse->pConstExpr list and evaluated once when
** the prepared statement starts up.  See sqlite3ExprCodeRunJustOnce().
*/
static int sqlite3ExprIsConstantNotJoin(Parse *pParse, Expr *p){
  return exprIsConst(pParse, p, 2);
}

/*
** This routine examines sub-SELECT statements as an expression is being
** walked as part of sqlite3ExprIsTableConstant().  Sub-SELECTs are considered
** constant as long as they are uncorrelated - meaning that they do not
** contain any terms from outer contexts.
*/
static int exprSelectWalkTableConstant(Walker *pWalker, Select *pSelect){
  assert( pSelect!=0 );
  assert( pWalker->eCode==3 || pWalker->eCode==0 );
  if( (pSelect->selFlags & SF_Correlated)!=0 ){
    pWalker->eCode = 0;
    return WRC_Abort;
  }
  return WRC_Prune;
}

/*
** Walk an expression tree.  Return non-zero if the expression is constant
** for any single row of the table with cursor iCur.  In other words, the
** expression must not refer to any non-deterministic function nor any
** table other than iCur.
**
** Consider uncorrelated subqueries to be constants if the bAllowSubq
** parameter is true.
*/
static int sqlite3ExprIsTableConstant(Expr *p, int iCur, int bAllowSubq){
  Walker w;
  w.eCode = 3;
  w.pParse = 0;
  w.xExprCallback = exprNodeIsConstant;
  if( bAllowSubq ){
    w.xSelectCallback = exprSelectWalkTableConstant;
  }else{
    w.xSelectCallback = sqlite3SelectWalkFail;
#ifdef SQLITE_DEBUG
    w.xSelectCallback2 = sqlite3SelectWalkAssert2;
#endif
  }
  w.u.iCur = iCur;
  sqlite3WalkExpr(&w, p);
  return w.eCode;
}

/*
** Check pExpr to see if it is an constraint on the single data source
** pSrc = &pSrcList->a[iSrc].  In other words, check to see if pExpr
** constrains pSrc but does not depend on any other tables or data
** sources anywhere else in the query.  Return true (non-zero) if pExpr
** is a constraint on pSrc only.
**
** This is an optimization.  False negatives will perhaps cause slower
** queries, but false positives will yield incorrect answers.  So when in
** doubt, return 0.
**
** To be an single-source constraint, the following must be true:
**
**   (1)  pExpr cannot refer to any table other than pSrc->iCursor.
**
**   (2a) pExpr cannot use subqueries unless the bAllowSubq parameter is
**        true and the subquery is non-correlated
**
**   (2b) pExpr cannot use non-deterministic functions.
**
**   (3)  pSrc cannot be part of the left operand for a RIGHT JOIN.
**        (Is there some way to relax this constraint?)
**
**   (4)  If pSrc is the right operand of a LEFT JOIN, then...
**         (4a)  pExpr must come from an ON clause..
**         (4b)  and specifically the ON clause associated with the LEFT JOIN.
**
**   (5)  If pSrc is the right operand of a LEFT JOIN or the left
**        operand of a RIGHT JOIN, then pExpr must be from the WHERE
**        clause, not an ON clause.
**
**   (6) Either:
**
**       (6a) pExpr does not originate in an ON or USING clause, or
**
**       (6b) The ON or USING clause from which pExpr is derived is

sqlite3.c  view on Meta::CPAN

  assert( pTab!=0 );
  assert( !IsView(pTab)  );              /* FROM clause is not a view */
  if( IsVirtual(pTab) ) return 0;        /* FROM clause not a virtual table */
  pEList = p->pEList;
  assert( pEList!=0 );
  /* All SELECT results must be columns. */
  for(i=0; i<pEList->nExpr; i++){
    Expr *pRes = pEList->a[i].pExpr;
    if( pRes->op!=TK_COLUMN ) return 0;
    assert( pRes->iTable==pSrc->a[0].iCursor );  /* Not a correlated subquery */
  }
  return p;
}
#endif /* SQLITE_OMIT_SUBQUERY */

#ifndef SQLITE_OMIT_SUBQUERY
/*
** Generate code that checks the left-most column of index table iCur to see if
** it contains any NULL entries.  Cause the register at regHasNull to be set
** to a non-NULL value if iCur contains no NULLs.  Cause register regHasNull
** to be set to NULL if iCur contains one or more NULL values.
*/
static void sqlite3SetHasNullFlag(Vdbe *v, int iCur, int regHasNull){
  int addr1;
  sqlite3VdbeAddOp2(v, OP_Integer, 0, regHasNull);
  addr1 = sqlite3VdbeAddOp1(v, OP_Rewind, iCur); VdbeCoverage(v);
  sqlite3VdbeAddOp3(v, OP_Column, iCur, 0, regHasNull);
  sqlite3VdbeChangeP5(v, OPFLAG_TYPEOFARG);
  VdbeComment((v, "first_entry_in(%d)", iCur));
  sqlite3VdbeJumpHere(v, addr1);
}
#endif


#ifndef SQLITE_OMIT_SUBQUERY
/*
** The argument is an IN operator with a list (not a subquery) on the
** right-hand side.  Return TRUE if that list is constant.
*/
static int sqlite3InRhsIsConstant(Parse *pParse, Expr *pIn){
  Expr *pLHS;
  int res;
  assert( !ExprHasProperty(pIn, EP_xIsSelect) );
  pLHS = pIn->pLeft;
  pIn->pLeft = 0;
  res = sqlite3ExprIsConstant(pParse, pIn);
  pIn->pLeft = pLHS;
  return res;
}
#endif

/*
** This function is used by the implementation of the IN (...) operator.
** The pX parameter is the expression on the RHS of the IN operator, which
** might be either a list of expressions or a subquery.
**
** The job of this routine is to find or create a b-tree object that can
** be used either to test for membership in the RHS set or to iterate through
** all members of the RHS set, skipping duplicates.
**
** A cursor is opened on the b-tree object that is the RHS of the IN operator
** and the *piTab parameter is set to the index of that cursor.
**
** The returned value of this function indicates the b-tree type, as follows:
**
**   IN_INDEX_ROWID      - The cursor was opened on a database table.
**   IN_INDEX_INDEX_ASC  - The cursor was opened on an ascending index.
**   IN_INDEX_INDEX_DESC - The cursor was opened on a descending index.
**   IN_INDEX_EPH        - The cursor was opened on a specially created and
**                         populated ephemeral table.
**   IN_INDEX_NOOP       - No cursor was allocated.  The IN operator must be
**                         implemented as a sequence of comparisons.
**
** An existing b-tree might be used if the RHS expression pX is a simple
** subquery such as:
**
**     SELECT <column1>, <column2>... FROM <table>
**
** If the RHS of the IN operator is a list or a more complex subquery, then
** an ephemeral table might need to be generated from the RHS and then
** pX->iTable made to point to the ephemeral table instead of an
** existing table.  In this case, the creation and initialization of the
** ephemeral table might be put inside of a subroutine, the EP_Subrtn flag
** will be set on pX and the pX->y.sub fields will be set to show where
** the subroutine is coded.
**
** The inFlags parameter must contain, at a minimum, one of the bits
** IN_INDEX_MEMBERSHIP or IN_INDEX_LOOP but not both.  If inFlags contains
** IN_INDEX_MEMBERSHIP, then the generated table will be used for a fast
** membership test.  When the IN_INDEX_LOOP bit is set, the IN index will
** be used to loop over all values of the RHS of the IN operator.
**
** When IN_INDEX_LOOP is used (and the b-tree will be used to iterate
** through the set members) then the b-tree must not contain duplicates.
** An ephemeral table will be created unless the selected columns are guaranteed
** to be unique - either because it is an INTEGER PRIMARY KEY or due to
** a UNIQUE constraint or index.
**
** When IN_INDEX_MEMBERSHIP is used (and the b-tree will be used
** for fast set membership tests) then an ephemeral table must
** be used unless <columns> is a single INTEGER PRIMARY KEY column or an
** index can be found with the specified <columns> as its left-most.
**
** If the IN_INDEX_NOOP_OK and IN_INDEX_MEMBERSHIP are both set and
** if the RHS of the IN operator is a list (not a subquery) then this
** routine might decide that creating an ephemeral b-tree for membership
** testing is too expensive and return IN_INDEX_NOOP.  In that case, the
** calling routine should implement the IN operator using a sequence
** of Eq or Ne comparison operations.
**
** When the b-tree is being used for membership tests, the calling function
** might need to know whether or not the RHS side of the IN operator
** contains a NULL.  If prRhsHasNull is not a NULL pointer and
** if there is any chance that the (...) might contain a NULL value at
** runtime, then a register is allocated and the register number written
** to *prRhsHasNull. If there is no chance that the (...) contains a
** NULL value, then *prRhsHasNull is left unchanged.
**
** If a register is allocated and its location stored in *prRhsHasNull, then
** the value in that register will be NULL if the b-tree contains one or more
** NULL values, and it will be some non-NULL value if the b-tree contains no
** NULL values.
**
** If the aiMap parameter is not NULL, it must point to an array containing
** one element for each column returned by the SELECT statement on the RHS
** of the IN(...) operator. The i'th entry of the array is populated with the
** offset of the index column that matches the i'th column returned by the
** SELECT. For example, if the expression and selected index are:
**
**   (?,?,?) IN (SELECT a, b, c FROM t1)
**   CREATE INDEX i1 ON t1(b, c, a);

sqlite3.c  view on Meta::CPAN

            int j;

            for(j=0; j<nExpr; j++){
              if( pIdx->aiColumn[j]!=pRhs->iColumn ) continue;
              assert( pIdx->azColl[j] );
              if( pReq!=0 && sqlite3StrICmp(pReq->zName, pIdx->azColl[j])!=0 ){
                continue;
              }
              break;
            }
            if( j==nExpr ) break;
            mCol = MASKBIT(j);
            if( mCol & colUsed ) break; /* Each column used only once */
            colUsed |= mCol;
            if( aiMap ) aiMap[i] = j;
          }

          assert( nExpr>0 && nExpr<BMS );
          assert( i==nExpr || colUsed!=(MASKBIT(nExpr)-1) );
          if( colUsed==(MASKBIT(nExpr)-1) ){
            /* If we reach this point, that means the index pIdx is usable */
            int iAddr = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
            ExplainQueryPlan((pParse, 0,
                              "USING INDEX %s FOR IN-OPERATOR",pIdx->zName));
            sqlite3VdbeAddOp3(v, OP_OpenRead, iTab, pIdx->tnum, iDb);
            sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
            VdbeComment((v, "%s", pIdx->zName));
            assert( IN_INDEX_INDEX_DESC == IN_INDEX_INDEX_ASC+1 );
            eType = IN_INDEX_INDEX_ASC + pIdx->aSortOrder[0];

            if( prRhsHasNull ){
#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
              i64 mask = (1<<nExpr)-1;
              sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed,
                  iTab, 0, 0, (u8*)&mask, P4_INT64);
#endif
              *prRhsHasNull = ++pParse->nMem;
              if( nExpr==1 ){
                sqlite3SetHasNullFlag(v, iTab, *prRhsHasNull);
              }
            }
            sqlite3VdbeJumpHere(v, iAddr);
          }
        } /* End loop over indexes */
      } /* End if( affinity_ok ) */
    } /* End if not an rowid index */
  } /* End attempt to optimize using an index */

  /* If no preexisting index is available for the IN clause
  ** and IN_INDEX_NOOP is an allowed reply
  ** and the RHS of the IN operator is a list, not a subquery
  ** and the RHS is not constant or has two or fewer terms,
  ** then it is not worth creating an ephemeral table to evaluate
  ** the IN operator so return IN_INDEX_NOOP.
  */
  if( eType==0
   && (inFlags & IN_INDEX_NOOP_OK)
   && ExprUseXList(pX)
   && (!sqlite3InRhsIsConstant(pParse,pX) || pX->x.pList->nExpr<=2)
  ){
    pParse->nTab--;  /* Back out the allocation of the unused cursor */
    iTab = -1;       /* Cursor is not allocated */
    eType = IN_INDEX_NOOP;
  }

  if( eType==0 ){
    /* Could not find an existing table or index to use as the RHS b-tree.
    ** We will have to generate an ephemeral table to do the job.
    */
    u32 savedNQueryLoop = pParse->nQueryLoop;
    int rMayHaveNull = 0;
    eType = IN_INDEX_EPH;
    if( inFlags & IN_INDEX_LOOP ){
      pParse->nQueryLoop = 0;
    }else if( prRhsHasNull ){
      *prRhsHasNull = rMayHaveNull = ++pParse->nMem;
    }
    assert( pX->op==TK_IN );
    sqlite3CodeRhsOfIN(pParse, pX, iTab);
    if( rMayHaveNull ){
      sqlite3SetHasNullFlag(v, iTab, rMayHaveNull);
    }
    pParse->nQueryLoop = savedNQueryLoop;
  }

  if( aiMap && eType!=IN_INDEX_INDEX_ASC && eType!=IN_INDEX_INDEX_DESC ){
    int i, n;
    n = sqlite3ExprVectorSize(pX->pLeft);
    for(i=0; i<n; i++) aiMap[i] = i;
  }
  *piTab = iTab;
  return eType;
}
#endif

#ifndef SQLITE_OMIT_SUBQUERY
/*
** Argument pExpr is an (?, ?...) IN(...) expression. This
** function allocates and returns a nul-terminated string containing
** the affinities to be used for each column of the comparison.
**
** It is the responsibility of the caller to ensure that the returned
** string is eventually freed using sqlite3DbFree().
*/
static char *exprINAffinity(Parse *pParse, const Expr *pExpr){
  Expr *pLeft = pExpr->pLeft;
  int nVal = sqlite3ExprVectorSize(pLeft);
  Select *pSelect = ExprUseXSelect(pExpr) ? pExpr->x.pSelect : 0;
  char *zRet;

  assert( pExpr->op==TK_IN );
  zRet = sqlite3DbMallocRaw(pParse->db, 1+(i64)nVal);
  if( zRet ){
    int i;
    for(i=0; i<nVal; i++){
      Expr *pA = sqlite3VectorFieldSubexpr(pLeft, i);
      char a = sqlite3ExprAffinity(pA);
      if( pSelect ){
        zRet[i] = sqlite3CompareAffinity(pSelect->pEList->a[i].pExpr, a);
      }else{
        zRet[i] = a;

sqlite3.c  view on Meta::CPAN

  }else
#endif
  {
    sqlite3ErrorMsg(pParse, "row value misused");
  }
}

#ifndef SQLITE_OMIT_SUBQUERY
/*
** Scan all previously generated bytecode looking for an OP_BeginSubrtn
** that is compatible with pExpr.  If found, add the y.sub values
** to pExpr and return true.  If not found, return false.
*/
static int findCompatibleInRhsSubrtn(
  Parse *pParse,          /* Parsing context */
  Expr *pExpr,            /* IN operator with RHS that we want to reuse */
  SubrtnSig *pNewSig      /* Signature for the IN operator */
){
  VdbeOp *pOp, *pEnd;
  SubrtnSig *pSig;
  Vdbe *v;

  if( pNewSig==0 ) return 0;
  if( (pParse->mSubrtnSig & (1<<(pNewSig->selId&7)))==0 ) return 0;
  assert( pExpr->op==TK_IN );
  assert( !ExprUseYSub(pExpr) );
  assert( ExprUseXSelect(pExpr) );
  assert( pExpr->x.pSelect!=0 );
  assert( (pExpr->x.pSelect->selFlags & SF_All)==0 );
  v = pParse->pVdbe;
  assert( v!=0 );
  pOp = sqlite3VdbeGetOp(v, 1);
  pEnd = sqlite3VdbeGetLastOp(v);
  for(; pOp<pEnd; pOp++){
    if( pOp->p4type!=P4_SUBRTNSIG ) continue;
    assert( pOp->opcode==OP_BeginSubrtn );
    pSig = pOp->p4.pSubrtnSig;
    assert( pSig!=0 );
    if( !pSig->bComplete ) continue;
    if( pNewSig->selId!=pSig->selId ) continue;
    if( strcmp(pNewSig->zAff,pSig->zAff)!=0 ) continue;
    pExpr->y.sub.iAddr = pSig->iAddr;
    pExpr->y.sub.regReturn = pSig->regReturn;
    pExpr->iTable = pSig->iTable;
    ExprSetProperty(pExpr, EP_Subrtn);
    return 1;
  }
  return 0;
}
#endif /* SQLITE_OMIT_SUBQUERY */

#ifndef SQLITE_OMIT_SUBQUERY
/*
** Generate code that will construct an ephemeral table containing all terms
** in the RHS of an IN operator.  The IN operator can be in either of two
** forms:
**
**     x IN (4,5,11)              -- IN operator with list on right-hand side
**     x IN (SELECT a FROM b)     -- IN operator with subquery on the right
**
** The pExpr parameter is the IN operator.  The cursor number for the
** constructed ephemeral table is returned.  The first time the ephemeral
** table is computed, the cursor number is also stored in pExpr->iTable,
** however the cursor number returned might not be the same, as it might
** have been duplicated using OP_OpenDup.
**
** If the LHS expression ("x" in the examples) is a column value, or
** the SELECT statement returns a column value, then the affinity of that
** column is used to build the index keys. If both 'x' and the
** SELECT... statement are columns, then numeric affinity is used
** if either column has NUMERIC or INTEGER affinity. If neither
** 'x' nor the SELECT... statement are columns, then numeric affinity
** is used.
*/
SQLITE_PRIVATE void sqlite3CodeRhsOfIN(
  Parse *pParse,          /* Parsing context */
  Expr *pExpr,            /* The IN operator */
  int iTab                /* Use this cursor number */
){
  int addrOnce = 0;           /* Address of the OP_Once instruction at top */
  int addr;                   /* Address of OP_OpenEphemeral instruction */
  Expr *pLeft;                /* the LHS of the IN operator */
  KeyInfo *pKeyInfo = 0;      /* Key information */
  int nVal;                   /* Size of vector pLeft */
  Vdbe *v;                    /* The prepared statement under construction */
  SubrtnSig *pSig = 0;        /* Signature for this subroutine */

  v = pParse->pVdbe;
  assert( v!=0 );

  /* The evaluation of the IN must be repeated every time it
  ** is encountered if any of the following is true:
  **
  **    *  The right-hand side is a correlated subquery
  **    *  The right-hand side is an expression list containing variables
  **    *  We are inside a trigger
  **
  ** If all of the above are false, then we can compute the RHS just once
  ** and reuse it many names.
  */
  if( !ExprHasProperty(pExpr, EP_VarSelect) && pParse->iSelfTab==0 ){
    /* Reuse of the RHS is allowed
    **
    ** Compute a signature for the RHS of the IN operator to facility
    ** finding and reusing prior instances of the same IN operator.
    */
    assert( !ExprUseXSelect(pExpr) || pExpr->x.pSelect!=0 );
    if( ExprUseXSelect(pExpr) && (pExpr->x.pSelect->selFlags & SF_All)==0 ){
      pSig = sqlite3DbMallocRawNN(pParse->db, sizeof(pSig[0]));
      if( pSig ){
        pSig->selId = pExpr->x.pSelect->selId;
        pSig->zAff = exprINAffinity(pParse, pExpr);
      }
    }

    /* Check to see if there is a prior materialization of the RHS of
    ** this IN operator.  If there is, then make use of that prior
    ** materialization rather than recomputing it.
    */
    if( ExprHasProperty(pExpr, EP_Subrtn)
     || findCompatibleInRhsSubrtn(pParse, pExpr, pSig)
    ){
      addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
      if( ExprUseXSelect(pExpr) ){
        ExplainQueryPlan((pParse, 0, "REUSE LIST SUBQUERY %d",
              pExpr->x.pSelect->selId));
      }
      assert( ExprUseYSub(pExpr) );
      sqlite3VdbeAddOp2(v, OP_Gosub, pExpr->y.sub.regReturn,
                        pExpr->y.sub.iAddr);
      assert( iTab!=pExpr->iTable );
      sqlite3VdbeAddOp2(v, OP_OpenDup, iTab, pExpr->iTable);
      sqlite3VdbeJumpHere(v, addrOnce);
      if( pSig ){
        sqlite3DbFree(pParse->db, pSig->zAff);
        sqlite3DbFree(pParse->db, pSig);
      }
      return;

sqlite3.c  view on Meta::CPAN


#ifndef SQLITE_OMIT_SUBQUERY
/*
** Generate code for an IN expression.
**
**      x IN (SELECT ...)
**      x IN (value, value, ...)
**
** The left-hand side (LHS) is a scalar or vector expression.  The
** right-hand side (RHS) is an array of zero or more scalar values, or a
** subquery.  If the RHS is a subquery, the number of result columns must
** match the number of columns in the vector on the LHS.  If the RHS is
** a list of values, the LHS must be a scalar.
**
** The IN operator is true if the LHS value is contained within the RHS.
** The result is false if the LHS is definitely not in the RHS.  The
** result is NULL if the presence of the LHS in the RHS cannot be
** determined due to NULLs.
**
** This routine generates code that jumps to destIfFalse if the LHS is not
** contained within the RHS.  If due to NULLs we cannot determine if the LHS
** is contained in the RHS then jump to destIfNull.  If the LHS is contained
** within the RHS then fall through.
**
** See the separate in-operator.md documentation file in the canonical
** SQLite source tree for additional information.
*/
static void sqlite3ExprCodeIN(
  Parse *pParse,        /* Parsing and code generating context */
  Expr *pExpr,          /* The IN expression */
  int destIfFalse,      /* Jump here if LHS is not contained in the RHS */
  int destIfNull        /* Jump here if the results are unknown due to NULLs */
){
  int rRhsHasNull = 0;  /* Register that is true if RHS contains NULL values */
  int eType;            /* Type of the RHS */
  int rLhs;             /* Register(s) holding the LHS values */
  Vdbe *v;              /* Statement under construction */
  int *aiMap = 0;       /* Map from vector field to index column */
  char *zAff = 0;       /* Affinity string for comparisons */
  int nVector;          /* Size of vectors for this IN operator */
  int iDummy;           /* Dummy parameter to exprCodeVector() */
  Expr *pLeft;          /* The LHS of the IN operator */
  int i;                /* loop counter */
  int destStep2;        /* Where to jump when NULLs seen in step 2 */
  int destStep6 = 0;    /* Start of code for Step 6 */
  int addrTruthOp;      /* Address of opcode that determines the IN is true */
  int destNotNull;      /* Jump here if a comparison is not true in step 6 */
  int addrTop;          /* Top of the step-6 loop */
  int iTab = 0;         /* Index to use */
  u8 okConstFactor = pParse->okConstFactor;

  assert( !ExprHasVVAProperty(pExpr,EP_Immutable) );
  pLeft = pExpr->pLeft;
  if( sqlite3ExprCheckIN(pParse, pExpr) ) return;
  zAff = exprINAffinity(pParse, pExpr);
  nVector = sqlite3ExprVectorSize(pExpr->pLeft);
  aiMap = (int*)sqlite3DbMallocZero(pParse->db, nVector*sizeof(int));
  if( pParse->db->mallocFailed ) goto sqlite3ExprCodeIN_oom_error;

  /* Attempt to compute the RHS. After this step, if anything other than
  ** IN_INDEX_NOOP is returned, the table opened with cursor iTab
  ** contains the values that make up the RHS. If IN_INDEX_NOOP is returned,
  ** the RHS has not yet been coded.  */
  v = pParse->pVdbe;
  assert( v!=0 );       /* OOM detected prior to this routine */
  VdbeNoopComment((v, "begin IN expr"));
  eType = sqlite3FindInIndex(pParse, pExpr,
                             IN_INDEX_MEMBERSHIP | IN_INDEX_NOOP_OK,
                             destIfFalse==destIfNull ? 0 : &rRhsHasNull,
                             aiMap, &iTab);

  assert( pParse->nErr || nVector==1 || eType==IN_INDEX_EPH
       || eType==IN_INDEX_INDEX_ASC || eType==IN_INDEX_INDEX_DESC
  );
#ifdef SQLITE_DEBUG
  /* Confirm that aiMap[] contains nVector integer values between 0 and
  ** nVector-1. */
  for(i=0; i<nVector; i++){
    int j, cnt;
    for(cnt=j=0; j<nVector; j++) if( aiMap[j]==i ) cnt++;
    assert( cnt==1 );
  }
#endif

  /* Code the LHS, the <expr> from "<expr> IN (...)". If the LHS is a
  ** vector, then it is stored in an array of nVector registers starting
  ** at r1.
  **
  ** sqlite3FindInIndex() might have reordered the fields of the LHS vector
  ** so that the fields are in the same order as an existing index.   The
  ** aiMap[] array contains a mapping from the original LHS field order to
  ** the field order that matches the RHS index.
  **
  ** Avoid factoring the LHS of the IN(...) expression out of the loop,
  ** even if it is constant, as OP_Affinity may be used on the register
  ** by code generated below.  */
  assert( pParse->okConstFactor==okConstFactor );
  pParse->okConstFactor = 0;
  rLhs = exprCodeVector(pParse, pLeft, &iDummy);
  pParse->okConstFactor = okConstFactor;

  /* If sqlite3FindInIndex() did not find or create an index that is
  ** suitable for evaluating the IN operator, then evaluate using a
  ** sequence of comparisons.
  **
  ** This is step (1) in the in-operator.md optimized algorithm.
  */
  if( eType==IN_INDEX_NOOP ){
    ExprList *pList;
    CollSeq *pColl;
    int labelOk = sqlite3VdbeMakeLabel(pParse);
    int r2, regToFree;
    int regCkNull = 0;
    int ii;
    assert( nVector==1 );
    assert( ExprUseXList(pExpr) );
    pList = pExpr->x.pList;
    pColl = sqlite3ExprCollSeq(pParse, pExpr->pLeft);
    if( destIfNull!=destIfFalse ){
      regCkNull = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp3(v, OP_BitAnd, rLhs, rLhs, regCkNull);

sqlite3.c  view on Meta::CPAN

  Parse *pParse,  /* The parsing context */
  Index *pIdx,    /* The index whose column is to be loaded */
  int iTabCur,    /* Cursor pointing to a table row */
  int iIdxCol,    /* The column of the index to be loaded */
  int regOut      /* Store the index column value in this register */
){
  i16 iTabCol = pIdx->aiColumn[iIdxCol];
  if( iTabCol==XN_EXPR ){
    assert( pIdx->aColExpr );
    assert( pIdx->aColExpr->nExpr>iIdxCol );
    pParse->iSelfTab = iTabCur + 1;
    sqlite3ExprCodeCopy(pParse, pIdx->aColExpr->a[iIdxCol].pExpr, regOut);
    pParse->iSelfTab = 0;
  }else{
    sqlite3ExprCodeGetColumnOfTable(pParse->pVdbe, pIdx->pTable, iTabCur,
                                    iTabCol, regOut);
  }
}

#ifndef SQLITE_OMIT_GENERATED_COLUMNS
/*
** Generate code that will compute the value of generated column pCol
** and store the result in register regOut
*/
SQLITE_PRIVATE void sqlite3ExprCodeGeneratedColumn(
  Parse *pParse,     /* Parsing context */
  Table *pTab,       /* Table containing the generated column */
  Column *pCol,      /* The generated column */
  int regOut         /* Put the result in this register */
){
  int iAddr;
  Vdbe *v = pParse->pVdbe;
  int nErr = pParse->nErr;
  assert( v!=0 );
  assert( pParse->iSelfTab!=0 );
  if( pParse->iSelfTab>0 ){
    iAddr = sqlite3VdbeAddOp3(v, OP_IfNullRow, pParse->iSelfTab-1, 0, regOut);
  }else{
    iAddr = 0;
  }
  sqlite3ExprCodeCopy(pParse, sqlite3ColumnExpr(pTab,pCol), regOut);
  if( (pCol->colFlags & COLFLAG_VIRTUAL)!=0
   && (pTab->tabFlags & TF_Strict)!=0
  ){
    int p3 = 2+(int)(pCol - pTab->aCol);
    sqlite3VdbeAddOp4(v, OP_TypeCheck, regOut, 1, p3, (char*)pTab, P4_TABLE);
  }else if( pCol->affinity>=SQLITE_AFF_TEXT ){
    sqlite3VdbeAddOp4(v, OP_Affinity, regOut, 1, 0, &pCol->affinity, 1);
  }
  if( iAddr ) sqlite3VdbeJumpHere(v, iAddr);
  if( pParse->nErr>nErr ) pParse->db->errByteOffset = -1;
}
#endif /* SQLITE_OMIT_GENERATED_COLUMNS */

/*
** Generate code to extract the value of the iCol-th column of a table.
*/
SQLITE_PRIVATE void sqlite3ExprCodeGetColumnOfTable(
  Vdbe *v,        /* Parsing context */
  Table *pTab,    /* The table containing the value */
  int iTabCur,    /* The table cursor.  Or the PK cursor for WITHOUT ROWID */
  int iCol,       /* Index of the column to extract */
  int regOut      /* Extract the value into this register */
){
  Column *pCol;
  assert( v!=0 );
  assert( pTab!=0 );
  assert( iCol!=XN_EXPR );
  if( iCol<0 || iCol==pTab->iPKey ){
    sqlite3VdbeAddOp2(v, OP_Rowid, iTabCur, regOut);
    VdbeComment((v, "%s.rowid", pTab->zName));
  }else{
    int op;
    int x;
    if( IsVirtual(pTab) ){
      op = OP_VColumn;
      x = iCol;
#ifndef SQLITE_OMIT_GENERATED_COLUMNS
    }else if( (pCol = &pTab->aCol[iCol])->colFlags & COLFLAG_VIRTUAL ){
      Parse *pParse = sqlite3VdbeParser(v);
      if( pCol->colFlags & COLFLAG_BUSY ){
        sqlite3ErrorMsg(pParse, "generated column loop on \"%s\"",
                        pCol->zCnName);
      }else{
        int savedSelfTab = pParse->iSelfTab;
        pCol->colFlags |= COLFLAG_BUSY;
        pParse->iSelfTab = iTabCur+1;
        sqlite3ExprCodeGeneratedColumn(pParse, pTab, pCol, regOut);
        pParse->iSelfTab = savedSelfTab;
        pCol->colFlags &= ~COLFLAG_BUSY;
      }
      return;
#endif
    }else if( !HasRowid(pTab) ){
      testcase( iCol!=sqlite3TableColumnToStorage(pTab, iCol) );
      x = sqlite3TableColumnToIndex(sqlite3PrimaryKeyIndex(pTab), iCol);
      op = OP_Column;
    }else{
      x = sqlite3TableColumnToStorage(pTab,iCol);
      testcase( x!=iCol );
      op = OP_Column;
    }
    sqlite3VdbeAddOp3(v, op, iTabCur, x, regOut);
    sqlite3ColumnDefault(v, pTab, iCol, regOut);
  }
}

/*
** Generate code that will extract the iColumn-th column from
** table pTab and store the column value in register iReg.
**
** There must be an open cursor to pTab in iTable when this routine
** is called.  If iColumn<0 then code is generated that extracts the rowid.
*/
SQLITE_PRIVATE int sqlite3ExprCodeGetColumn(
  Parse *pParse,   /* Parsing and code generating context */
  Table *pTab,     /* Description of the table we are reading from */
  int iColumn,     /* Index of the table column */
  int iTable,      /* The cursor pointing to the table */
  int iReg,        /* Store results here */
  u8 p5            /* P5 value for OP_Column + FLAGS */
){
  assert( pParse->pVdbe!=0 );
  assert( (p5 & (OPFLAG_NOCHNG|OPFLAG_TYPEOFARG|OPFLAG_LENGTHARG))==p5 );
  assert( IsVirtual(pTab) || (p5 & OPFLAG_NOCHNG)==0 );
  sqlite3ExprCodeGetColumnOfTable(pParse->pVdbe, pTab, iTable, iColumn, iReg);
  if( p5 ){
    VdbeOp *pOp = sqlite3VdbeGetLastOp(pParse->pVdbe);
    if( pOp->opcode==OP_Column ) pOp->p5 = p5;
    if( pOp->opcode==OP_VColumn ) pOp->p5 = (p5 & OPFLAG_NOCHNG);
  }
  return iReg;
}

/*
** Generate code to move content from registers iFrom...iFrom+nReg-1
** over to iTo..iTo+nReg-1.
*/
SQLITE_PRIVATE void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){
  sqlite3VdbeAddOp3(pParse->pVdbe, OP_Move, iFrom, iTo, nReg);
}

/*
** Convert a scalar expression node to a TK_REGISTER referencing
** register iReg.  The caller must ensure that iReg already contains
** the correct value for the expression.
*/
SQLITE_PRIVATE void sqlite3ExprToRegister(Expr *pExpr, int iReg){
  Expr *p = sqlite3ExprSkipCollateAndLikely(pExpr);
  if( NEVER(p==0) ) return;
  if( p->op==TK_REGISTER ){
    assert( p->iTable==iReg );
  }else{
    p->op2 = p->op;
    p->op = TK_REGISTER;
    p->iTable = iReg;
    ExprClearProperty(p, EP_Skip);
  }
}

/*
** Evaluate an expression (either a vector or a scalar expression) and store
** the result in contiguous temporary registers.  Return the index of
** the first register used to store the result.
**
** If the returned result register is a temporary scalar, then also write
** that register number into *piFreeable.  If the returned result register
** is not a temporary or if the expression is a vector set *piFreeable
** to 0.
*/
static int exprCodeVector(Parse *pParse, Expr *p, int *piFreeable){
  int iResult;
  int nResult = sqlite3ExprVectorSize(p);
  if( nResult==1 ){
    iResult = sqlite3ExprCodeTemp(pParse, p, piFreeable);
  }else{
    *piFreeable = 0;
    if( p->op==TK_SELECT ){
#if SQLITE_OMIT_SUBQUERY

sqlite3.c  view on Meta::CPAN

           && IsVirtual(pRight->y.pTab))
      ){
        return WRC_Prune;
      }
      /* no break */ deliberate_fall_through
    }
    default:
      return WRC_Continue;
  }
}

/*
** Return true (non-zero) if expression p can only be true if at least
** one column of table iTab is non-null.  In other words, return true
** if expression p will always be NULL or false if every column of iTab
** is NULL.
**
** False negatives are acceptable.  In other words, it is ok to return
** zero even if expression p will never be true of every column of iTab
** is NULL.  A false negative is merely a missed optimization opportunity.
**
** False positives are not allowed, however.  A false positive may result
** in an incorrect answer.
**
** Terms of p that are marked with EP_OuterON (and hence that come from
** the ON or USING clauses of OUTER JOINS) are excluded from the analysis.
**
** This routine is used to check if a LEFT JOIN can be converted into
** an ordinary JOIN.  The p argument is the WHERE clause.  If the WHERE
** clause requires that some column of the right table of the LEFT JOIN
** be non-NULL, then the LEFT JOIN can be safely converted into an
** ordinary join.
*/
SQLITE_PRIVATE int sqlite3ExprImpliesNonNullRow(Expr *p, int iTab, int isRJ){
  Walker w;
  p = sqlite3ExprSkipCollateAndLikely(p);
  if( p==0 ) return 0;
  if( p->op==TK_NOTNULL ){
    p = p->pLeft;
  }else{
    while( p->op==TK_AND ){
      if( sqlite3ExprImpliesNonNullRow(p->pLeft, iTab, isRJ) ) return 1;
      p = p->pRight;
    }
  }
  w.xExprCallback = impliesNotNullRow;
  w.xSelectCallback = 0;
  w.xSelectCallback2 = 0;
  w.eCode = 0;
  w.mWFlags = isRJ!=0;
  w.u.iCur = iTab;
  sqlite3WalkExpr(&w, p);
  return w.eCode;
}

/*
** An instance of the following structure is used by the tree walker
** to determine if an expression can be evaluated by reference to the
** index only, without having to do a search for the corresponding
** table entry.  The IdxCover.pIdx field is the index.  IdxCover.iCur
** is the cursor for the table.
*/
struct IdxCover {
  Index *pIdx;     /* The index to be tested for coverage */
  int iCur;        /* Cursor number for the table corresponding to the index */
};

/*
** Check to see if there are references to columns in table
** pWalker->u.pIdxCover->iCur can be satisfied using the index
** pWalker->u.pIdxCover->pIdx.
*/
static int exprIdxCover(Walker *pWalker, Expr *pExpr){
  if( pExpr->op==TK_COLUMN
   && pExpr->iTable==pWalker->u.pIdxCover->iCur
   && sqlite3TableColumnToIndex(pWalker->u.pIdxCover->pIdx, pExpr->iColumn)<0
  ){
    pWalker->eCode = 1;
    return WRC_Abort;
  }
  return WRC_Continue;
}

/*
** Determine if an index pIdx on table with cursor iCur contains will
** the expression pExpr.  Return true if the index does cover the
** expression and false if the pExpr expression references table columns
** that are not found in the index pIdx.
**
** An index covering an expression means that the expression can be
** evaluated using only the index and without having to lookup the
** corresponding table entry.
*/
SQLITE_PRIVATE int sqlite3ExprCoveredByIndex(
  Expr *pExpr,        /* The index to be tested */
  int iCur,           /* The cursor number for the corresponding table */
  Index *pIdx         /* The index that might be used for coverage */
){
  Walker w;
  struct IdxCover xcov;
  memset(&w, 0, sizeof(w));
  xcov.iCur = iCur;
  xcov.pIdx = pIdx;
  w.xExprCallback = exprIdxCover;
  w.u.pIdxCover = &xcov;
  sqlite3WalkExpr(&w, pExpr);
  return !w.eCode;
}


/* Structure used to pass information throughout the Walker in order to
** implement sqlite3ReferencesSrcList().
*/
struct RefSrcList {
  sqlite3 *db;         /* Database connection used for sqlite3DbRealloc() */
  SrcList *pRef;       /* Looking for references to these tables */
  i64 nExclude;        /* Number of tables to exclude from the search */
  int *aiExclude;      /* Cursor IDs for tables to exclude from the search */
};

/*
** Walker SELECT callbacks for sqlite3ReferencesSrcList().
**
** When entering a new subquery on the pExpr argument, add all FROM clause
** entries for that subquery to the exclude list.
**
** When leaving the subquery, remove those entries from the exclude list.
*/
static int selectRefEnter(Walker *pWalker, Select *pSelect){
  struct RefSrcList *p = pWalker->u.pRefSrcList;
  SrcList *pSrc = pSelect->pSrc;
  i64 i, j;
  int *piNew;
  if( pSrc->nSrc==0 ) return WRC_Continue;
  j = p->nExclude;
  p->nExclude += pSrc->nSrc;
  piNew = sqlite3DbRealloc(p->db, p->aiExclude, p->nExclude*sizeof(int));
  if( piNew==0 ){
    p->nExclude = 0;
    return WRC_Abort;
  }else{
    p->aiExclude = piNew;
  }
  for(i=0; i<pSrc->nSrc; i++, j++){
     p->aiExclude[j] = pSrc->a[i].iCursor;
  }
  return WRC_Continue;
}
static void selectRefLeave(Walker *pWalker, Select *pSelect){
  struct RefSrcList *p = pWalker->u.pRefSrcList;
  SrcList *pSrc = pSelect->pSrc;
  if( p->nExclude ){
    assert( p->nExclude>=pSrc->nSrc );
    p->nExclude -= pSrc->nSrc;
  }
}

sqlite3.c  view on Meta::CPAN

** of the INTEGER PRIMARY KEY.  The sample column is a blob which is the
** binary encoding of a key from the index.  The nEq column is a
** list of integers.  The first integer is the approximate number
** of entries in the index whose left-most column exactly matches
** the left-most column of the sample.  The second integer in nEq
** is the approximate number of entries in the index where the
** first two columns match the first two columns of the sample.
** And so forth.  nLt is another list of integers that show the approximate
** number of entries that are strictly less than the sample.  The first
** integer in nLt contains the number of entries in the index where the
** left-most column is less than the left-most column of the sample.
** The K-th integer in the nLt entry is the number of index entries
** where the first K columns are less than the first K columns of the
** sample.  The nDLt column is like nLt except that it contains the
** number of distinct entries in the index that are less than the
** sample.
**
** There can be an arbitrary number of sqlite_stat4 entries per index.
** The ANALYZE command will typically generate sqlite_stat4 tables
** that contain between 10 and 40 samples which are distributed across
** the key space, though not uniformly, and which include samples with
** large nEq values.
**
** Format for sqlite_stat3 redux:
**
** The sqlite_stat3 table is like sqlite_stat4 except that it only
** looks at the left-most column of the index.  The sqlite_stat3.sample
** column contains the actual value of the left-most column instead
** of a blob encoding of the complete index key as is found in
** sqlite_stat4.sample.  The nEq, nLt, and nDLt entries of sqlite_stat3
** all contain just a single integer which is the same as the first
** integer in the equivalent columns in sqlite_stat4.
*/
#ifndef SQLITE_OMIT_ANALYZE
/* #include "sqliteInt.h" */

#if defined(SQLITE_ENABLE_STAT4)
# define IsStat4     1
#else
# define IsStat4     0
# undef SQLITE_STAT4_SAMPLES
# define SQLITE_STAT4_SAMPLES 1
#endif

/*
** This routine generates code that opens the sqlite_statN tables.
** The sqlite_stat1 table is always relevant.  sqlite_stat2 is now
** obsolete.  sqlite_stat3 and sqlite_stat4 are only opened when
** appropriate compile-time options are provided.
**
** If the sqlite_statN tables do not previously exist, it is created.
**
** Argument zWhere may be a pointer to a buffer containing a table name,
** or it may be a NULL pointer. If it is not NULL, then all entries in
** the sqlite_statN tables associated with the named table are deleted.
** If zWhere==0, then code is generated to delete all stat table entries.
*/
static void openStatTable(
  Parse *pParse,          /* Parsing context */
  int iDb,                /* The database we are looking in */
  int iStatCur,           /* Open the sqlite_stat1 table on this cursor */
  const char *zWhere,     /* Delete entries for this table or index */
  const char *zWhereType  /* Either "tbl" or "idx" */
){
  static const struct {
    const char *zName;
    const char *zCols;
  } aTable[] = {
    { "sqlite_stat1", "tbl,idx,stat" },
#if defined(SQLITE_ENABLE_STAT4)
    { "sqlite_stat4", "tbl,idx,neq,nlt,ndlt,sample" },
#else
    { "sqlite_stat4", 0 },
#endif
    { "sqlite_stat3", 0 },
  };
  int i;
  sqlite3 *db = pParse->db;
  Db *pDb;
  Vdbe *v = sqlite3GetVdbe(pParse);
  u32 aRoot[ArraySize(aTable)];
  u8 aCreateTbl[ArraySize(aTable)];
#ifdef SQLITE_ENABLE_STAT4
  const int nToOpen = OptimizationEnabled(db,SQLITE_Stat4) ? 2 : 1;
#else
  const int nToOpen = 1;
#endif

  if( v==0 ) return;
  assert( sqlite3BtreeHoldsAllMutexes(db) );
  assert( sqlite3VdbeDb(v)==db );
  pDb = &db->aDb[iDb];

  /* Create new statistic tables if they do not exist, or clear them
  ** if they do already exist.
  */
  for(i=0; i<ArraySize(aTable); i++){
    const char *zTab = aTable[i].zName;
    Table *pStat;
    aCreateTbl[i] = 0;
    if( (pStat = sqlite3FindTable(db, zTab, pDb->zDbSName))==0 ){
      if( i<nToOpen ){
        /* The sqlite_statN table does not exist. Create it. Note that a
        ** side-effect of the CREATE TABLE statement is to leave the rootpage
        ** of the new table in register pParse->regRoot. This is important
        ** because the OpenWrite opcode below will be needing it. */
        sqlite3NestedParse(pParse,
            "CREATE TABLE %Q.%s(%s)", pDb->zDbSName, zTab, aTable[i].zCols
        );
        assert( pParse->isCreate || pParse->nErr );
        aRoot[i] = (u32)pParse->u1.cr.regRoot;
        aCreateTbl[i] = OPFLAG_P2ISREG;
      }
    }else{
      /* The table already exists. If zWhere is not NULL, delete all entries
      ** associated with the table zWhere. If zWhere is NULL, delete the
      ** entire contents of the table. */
      aRoot[i] = pStat->tnum;
      sqlite3TableLock(pParse, iDb, aRoot[i], 1, zTab);
      if( zWhere ){
        sqlite3NestedParse(pParse,

sqlite3.c  view on Meta::CPAN

static const FuncDef statGetFuncdef = {
  1+IsStat4,       /* nArg */
  SQLITE_UTF8,     /* funcFlags */
  0,               /* pUserData */
  0,               /* pNext */
  statGet,         /* xSFunc */
  0,               /* xFinalize */
  0, 0,            /* xValue, xInverse */
  "stat_get",      /* zName */
  {0}
};

static void callStatGet(Parse *pParse, int regStat, int iParam, int regOut){
#ifdef SQLITE_ENABLE_STAT4
  sqlite3VdbeAddOp2(pParse->pVdbe, OP_Integer, iParam, regStat+1);
#elif SQLITE_DEBUG
  assert( iParam==STAT_GET_STAT1 );
#else
  UNUSED_PARAMETER( iParam );
#endif
  assert( regOut!=regStat && regOut!=regStat+1 );
  sqlite3VdbeAddFunctionCall(pParse, 0, regStat, regOut, 1+IsStat4,
                             &statGetFuncdef, 0);
}

#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
/* Add a comment to the most recent VDBE opcode that is the name
** of the k-th column of the pIdx index.
*/
static void analyzeVdbeCommentIndexWithColumnName(
  Vdbe *v,         /* Prepared statement under construction */
  Index *pIdx,     /* Index whose column is being loaded */
  int k            /* Which column index */
){
  int i;           /* Index of column in the table */
  assert( k>=0 && k<pIdx->nColumn );
  i = pIdx->aiColumn[k];
  if( NEVER(i==XN_ROWID) ){
    VdbeComment((v,"%s.rowid",pIdx->zName));
  }else if( i==XN_EXPR ){
    assert( pIdx->bHasExpr );
    VdbeComment((v,"%s.expr(%d)",pIdx->zName, k));
  }else{
    VdbeComment((v,"%s.%s", pIdx->zName, pIdx->pTable->aCol[i].zCnName));
  }
}
#else
# define analyzeVdbeCommentIndexWithColumnName(a,b,c)
#endif /* SQLITE_DEBUG */

/*
** Generate code to do an analysis of all indices associated with
** a single table.
*/
static void analyzeOneTable(
  Parse *pParse,   /* Parser context */
  Table *pTab,     /* Table whose indices are to be analyzed */
  Index *pOnlyIdx, /* If not NULL, only analyze this one index */
  int iStatCur,    /* Index of VdbeCursor that writes the sqlite_stat1 table */
  int iMem,        /* Available memory locations begin here */
  int iTab         /* Next available cursor */
){
  sqlite3 *db = pParse->db;    /* Database handle */
  Index *pIdx;                 /* An index to being analyzed */
  int iIdxCur;                 /* Cursor open on index being analyzed */
  int iTabCur;                 /* Table cursor */
  Vdbe *v;                     /* The virtual machine being built up */
  int i;                       /* Loop counter */
  int jZeroRows = -1;          /* Jump from here if number of rows is zero */
  int iDb;                     /* Index of database containing pTab */
  u8 needTableCnt = 1;         /* True to count the table */
  int regNewRowid = iMem++;    /* Rowid for the inserted record */
  int regStat = iMem++;        /* Register to hold StatAccum object */
  int regChng = iMem++;        /* Index of changed index field */
  int regRowid = iMem++;       /* Rowid argument passed to stat_push() */
  int regTemp = iMem++;        /* Temporary use register */
  int regTemp2 = iMem++;       /* Second temporary use register */
  int regTabname = iMem++;     /* Register containing table name */
  int regIdxname = iMem++;     /* Register containing index name */
  int regStat1 = iMem++;       /* Value for the stat column of sqlite_stat1 */
  int regPrev = iMem;          /* MUST BE LAST (see below) */
#ifdef SQLITE_ENABLE_STAT4
  int doOnce = 1;              /* Flag for a one-time computation */
#endif
#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
  Table *pStat1 = 0;
#endif

  sqlite3TouchRegister(pParse, iMem);
  assert( sqlite3NoTempsInRange(pParse, regNewRowid, iMem) );
  v = sqlite3GetVdbe(pParse);
  if( v==0 || NEVER(pTab==0) ){
    return;
  }
  if( !IsOrdinaryTable(pTab) ){
    /* Do not gather statistics on views or virtual tables */
    return;
  }
  if( sqlite3_strlike("sqlite\\_%", pTab->zName, '\\')==0 ){
    /* Do not gather statistics on system tables */
    return;
  }
  assert( sqlite3BtreeHoldsAllMutexes(db) );
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb>=0 );
  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
#ifndef SQLITE_OMIT_AUTHORIZATION
  if( sqlite3AuthCheck(pParse, SQLITE_ANALYZE, pTab->zName, 0,
      db->aDb[iDb].zDbSName ) ){
    return;
  }
#endif

#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
  if( db->xPreUpdateCallback ){
    pStat1 = (Table*)sqlite3DbMallocZero(db, sizeof(Table) + 13);
    if( pStat1==0 ) return;
    pStat1->zName = (char*)&pStat1[1];
    memcpy(pStat1->zName, "sqlite_stat1", 13);
    pStat1->nCol = 3;
    pStat1->iPKey = -1;
    sqlite3VdbeAddOp4(pParse->pVdbe, OP_Noop, 0, 0, 0,(char*)pStat1,P4_DYNAMIC);
  }
#endif

  /* Establish a read-lock on the table at the shared-cache level.
  ** Open a read-only cursor on the table. Also allocate a cursor number
  ** to use for scanning indexes (iIdxCur). No index cursor is opened at
  ** this time though.  */
  sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
  iTabCur = iTab++;
  iIdxCur = iTab++;
  pParse->nTab = MAX(pParse->nTab, iTab);
  sqlite3OpenTable(pParse, iTabCur, iDb, pTab, OP_OpenRead);
  sqlite3VdbeLoadString(v, regTabname, pTab->zName);

  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    int nCol;                     /* Number of columns in pIdx. "N" */
    int addrGotoEnd;               /* Address of "OP_Rewind iIdxCur" */
    int addrNextRow;              /* Address of "next_row:" */
    const char *zIdxName;         /* Name of the index */
    int nColTest;                 /* Number of columns to test for changes */

    if( pOnlyIdx && pOnlyIdx!=pIdx ) continue;
    if( pIdx->pPartIdxWhere==0 ) needTableCnt = 0;
    if( !HasRowid(pTab) && IsPrimaryKeyIndex(pIdx) ){
      nCol = pIdx->nKeyCol;
      zIdxName = pTab->zName;
      nColTest = nCol - 1;
    }else{
      nCol = pIdx->nColumn;
      zIdxName = pIdx->zName;
      nColTest = pIdx->uniqNotNull ? pIdx->nKeyCol-1 : nCol-1;
    }

    /* Populate the register containing the index name. */
    sqlite3VdbeLoadString(v, regIdxname, zIdxName);
    VdbeComment((v, "Analysis for %s.%s", pTab->zName, zIdxName));

    /*
    ** Pseudo-code for loop that calls stat_push():
    **
    **   regChng = 0
    **   Rewind csr
    **   if eof(csr){
    **      stat_init() with count = 0;
    **      goto end_of_scan;
    **   }
    **   count()
    **   stat_init()
    **   goto chng_addr_0;
    **
    **  next_row:
    **   regChng = 0
    **   if( idx(0) != regPrev(0) ) goto chng_addr_0
    **   regChng = 1
    **   if( idx(1) != regPrev(1) ) goto chng_addr_1
    **   ...
    **   regChng = N
    **   goto chng_addr_N
    **
    **  chng_addr_0:
    **   regPrev(0) = idx(0)
    **  chng_addr_1:
    **   regPrev(1) = idx(1)
    **  ...
    **
    **  endDistinctTest:
    **   regRowid = idx(rowid)
    **   stat_push(P, regChng, regRowid)
    **   Next csr
    **   if !eof(csr) goto next_row;
    **
    **  end_of_scan:
    */

    /* Make sure there are enough memory cells allocated to accommodate
    ** the regPrev array and a trailing rowid (the rowid slot is required
    ** when building a record to insert into the sample column of
    ** the sqlite_stat4 table.  */
    sqlite3TouchRegister(pParse, regPrev+nColTest);

    /* Open a read-only cursor on the index being analyzed. */
    assert( iDb==sqlite3SchemaToIndex(db, pIdx->pSchema) );
    sqlite3VdbeAddOp3(v, OP_OpenRead, iIdxCur, pIdx->tnum, iDb);
    sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
    VdbeComment((v, "%s", pIdx->zName));

    /* Implementation of the following:
    **
    **   regChng = 0
    **   Rewind csr
    **   if eof(csr){
    **      stat_init() with count = 0;
    **      goto end_of_scan;
    **   }
    **   count()
    **   stat_init()
    **   goto chng_addr_0;
    */
    assert( regTemp2==regStat+4 );
    sqlite3VdbeAddOp2(v, OP_Integer, db->nAnalysisLimit, regTemp2);

    /* Arguments to stat_init():
    **    (1) the number of columns in the index including the rowid
    **        (or for a WITHOUT ROWID table, the number of PK columns),
    **    (2) the number of columns in the key without the rowid/pk
    **    (3) estimated number of rows in the index. */
    sqlite3VdbeAddOp2(v, OP_Integer, nCol, regStat+1);
    assert( regRowid==regStat+2 );
    sqlite3VdbeAddOp2(v, OP_Integer, pIdx->nKeyCol, regRowid);
    sqlite3VdbeAddOp3(v, OP_Count, iIdxCur, regTemp,
                      OptimizationDisabled(db, SQLITE_Stat4));
    sqlite3VdbeAddFunctionCall(pParse, 0, regStat+1, regStat, 4,
                               &statInitFuncdef, 0);
    addrGotoEnd = sqlite3VdbeAddOp1(v, OP_Rewind, iIdxCur);
    VdbeCoverage(v);

    sqlite3VdbeAddOp2(v, OP_Integer, 0, regChng);
    addrNextRow = sqlite3VdbeCurrentAddr(v);

    if( nColTest>0 ){
      int endDistinctTest = sqlite3VdbeMakeLabel(pParse);
      int *aGotoChng;               /* Array of jump instruction addresses */
      aGotoChng = sqlite3DbMallocRawNN(db, sizeof(int)*nColTest);
      if( aGotoChng==0 ) continue;

      /*
      **  next_row:
      **   regChng = 0
      **   if( idx(0) != regPrev(0) ) goto chng_addr_0
      **   regChng = 1
      **   if( idx(1) != regPrev(1) ) goto chng_addr_1
      **   ...
      **   regChng = N
      **   goto endDistinctTest
      */
      sqlite3VdbeAddOp0(v, OP_Goto);
      addrNextRow = sqlite3VdbeCurrentAddr(v);
      if( nColTest==1 && pIdx->nKeyCol==1 && IsUniqueIndex(pIdx) ){
        /* For a single-column UNIQUE index, once we have found a non-NULL
        ** row, we know that all the rest will be distinct, so skip
        ** subsequent distinctness tests. */

sqlite3.c  view on Meta::CPAN

      sqlite3VdbeAddOp4Int(v,
        OP_Transaction,                    /* Opcode */
        iDb,                               /* P1 */
        DbMaskTest(pParse->writeMask,iDb), /* P2 */
        pSchema->schema_cookie,            /* P3 */
        pSchema->iGeneration               /* P4 */
      );
      if( db->init.busy==0 ) sqlite3VdbeChangeP5(v, 1);
      VdbeComment((v,
            "usesStmtJournal=%d", pParse->mayAbort && pParse->isMultiWrite));
    }while( ++iDb<db->nDb );
#ifndef SQLITE_OMIT_VIRTUALTABLE
    for(i=0; i<pParse->nVtabLock; i++){
      char *vtab = (char *)sqlite3GetVTable(db, pParse->apVtabLock[i]);
      sqlite3VdbeAddOp4(v, OP_VBegin, 0, 0, 0, vtab, P4_VTAB);
    }
    pParse->nVtabLock = 0;
#endif

#ifndef SQLITE_OMIT_SHARED_CACHE
    /* Once all the cookies have been verified and transactions opened,
    ** obtain the required table-locks. This is a no-op unless the
    ** shared-cache feature is enabled.
    */
    if( pParse->nTableLock ) codeTableLocks(pParse);
#endif

    /* Initialize any AUTOINCREMENT data structures required.
    */
    if( pParse->pAinc ) sqlite3AutoincrementBegin(pParse);

    /* Code constant expressions that were factored out of inner loops.
    */
    if( pParse->pConstExpr ){
      ExprList *pEL = pParse->pConstExpr;
      pParse->okConstFactor = 0;
      for(i=0; i<pEL->nExpr; i++){
        assert( pEL->a[i].u.iConstExprReg>0 );
        sqlite3ExprCode(pParse, pEL->a[i].pExpr, pEL->a[i].u.iConstExprReg);
      }
    }

    if( pParse->bReturning ){
      Returning *pRet;
      assert( !pParse->isCreate );
      pRet = pParse->u1.d.pReturning;
      if( pRet->nRetCol ){
        sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pRet->iRetCur, pRet->nRetCol);
      }
    }

    /* Finally, jump back to the beginning of the executable code. */
    sqlite3VdbeGoto(v, 1);
  }

  /* Get the VDBE program ready for execution
  */
  assert( v!=0 || pParse->nErr );
  assert( db->mallocFailed==0 || pParse->nErr );
  if( pParse->nErr==0 ){
    /* A minimum of one cursor is required if autoincrement is used
    *  See ticket [a696379c1f08866] */
    assert( pParse->pAinc==0 || pParse->nTab>0 );
    sqlite3VdbeMakeReady(v, pParse);
    pParse->rc = SQLITE_DONE;
  }else{
    pParse->rc = SQLITE_ERROR;
  }
}

/*
** Run the parser and code generator recursively in order to generate
** code for the SQL statement given onto the end of the pParse context
** currently under construction.  Notes:
**
**   *  The final OP_Halt is not appended and other initialization
**      and finalization steps are omitted because those are handling by the
**      outermost parser.
**
**   *  Built-in SQL functions always take precedence over application-defined
**      SQL functions.  In other words, it is not possible to override a
**      built-in function.
*/
SQLITE_PRIVATE void sqlite3NestedParse(Parse *pParse, const char *zFormat, ...){
  va_list ap;
  char *zSql;
  sqlite3 *db = pParse->db;
  u32 savedDbFlags = db->mDbFlags;
  char saveBuf[PARSE_TAIL_SZ];

  if( pParse->nErr ) return;
  if( pParse->eParseMode ) return;
  assert( pParse->nested<10 );  /* Nesting should only be of limited depth */
  va_start(ap, zFormat);
  zSql = sqlite3VMPrintf(db, zFormat, ap);
  va_end(ap);
  if( zSql==0 ){
    /* This can result either from an OOM or because the formatted string
    ** exceeds SQLITE_LIMIT_LENGTH.  In the latter case, we need to set
    ** an error */
    if( !db->mallocFailed ) pParse->rc = SQLITE_TOOBIG;
    pParse->nErr++;
    return;
  }
  pParse->nested++;
  memcpy(saveBuf, PARSE_TAIL(pParse), PARSE_TAIL_SZ);
  memset(PARSE_TAIL(pParse), 0, PARSE_TAIL_SZ);
  db->mDbFlags |= DBFLAG_PreferBuiltin;
  sqlite3RunParser(pParse, zSql);
  db->mDbFlags = savedDbFlags;
  sqlite3DbFree(db, zSql);
  memcpy(PARSE_TAIL(pParse), saveBuf, PARSE_TAIL_SZ);
  pParse->nested--;
}

/*
** Locate the in-memory structure that describes a particular database
** table given the name of that table and (optionally) the name of the
** database containing the table.  Return NULL if not found.
**
** If zDatabase is 0, all databases are searched for the table and the

sqlite3.c  view on Meta::CPAN

  /* Verify that no lookaside memory was used by schema tables */
  assert( nLookaside==0 || nLookaside==sqlite3LookasideUsed(db,0) );
}
SQLITE_PRIVATE void sqlite3DeleteTable(sqlite3 *db, Table *pTable){
  /* Do not delete the table until the reference count reaches zero. */
  assert( db!=0 );
  if( !pTable ) return;
  if( db->pnBytesFreed==0 && (--pTable->nTabRef)>0 ) return;
  deleteTable(db, pTable);
}
SQLITE_PRIVATE void sqlite3DeleteTableGeneric(sqlite3 *db, void *pTable){
  sqlite3DeleteTable(db, (Table*)pTable);
}


/*
** Unlink the given table from the hash tables and the delete the
** table structure with all its indices and foreign keys.
*/
SQLITE_PRIVATE void sqlite3UnlinkAndDeleteTable(sqlite3 *db, int iDb, const char *zTabName){
  Table *p;
  Db *pDb;

  assert( db!=0 );
  assert( iDb>=0 && iDb<db->nDb );
  assert( zTabName );
  assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
  testcase( zTabName[0]==0 );  /* Zero-length table names are allowed */
  pDb = &db->aDb[iDb];
  p = sqlite3HashInsert(&pDb->pSchema->tblHash, zTabName, 0);
  sqlite3DeleteTable(db, p);
  db->mDbFlags |= DBFLAG_SchemaChange;
}

/*
** Given a token, return a string that consists of the text of that
** token.  Space to hold the returned string
** is obtained from sqliteMalloc() and must be freed by the calling
** function.
**
** Any quotation marks (ex:  "name", 'name', [name], or `name`) that
** surround the body of the token are removed.
**
** Tokens are often just pointers into the original SQL text and so
** are not \000 terminated and are not persistent.  The returned string
** is \000 terminated and is persistent.
*/
SQLITE_PRIVATE char *sqlite3NameFromToken(sqlite3 *db, const Token *pName){
  char *zName;
  if( pName ){
    zName = sqlite3DbStrNDup(db, (const char*)pName->z, pName->n);
    sqlite3Dequote(zName);
  }else{
    zName = 0;
  }
  return zName;
}

/*
** Open the sqlite_schema table stored in database number iDb for
** writing. The table is opened using cursor 0.
*/
SQLITE_PRIVATE void sqlite3OpenSchemaTable(Parse *p, int iDb){
  Vdbe *v = sqlite3GetVdbe(p);
  sqlite3TableLock(p, iDb, SCHEMA_ROOT, 1, LEGACY_SCHEMA_TABLE);
  sqlite3VdbeAddOp4Int(v, OP_OpenWrite, 0, SCHEMA_ROOT, iDb, 5);
  if( p->nTab==0 ){
    p->nTab = 1;
  }
}

/*
** Parameter zName points to a nul-terminated buffer containing the name
** of a database ("main", "temp" or the name of an attached db). This
** function returns the index of the named database in db->aDb[], or
** -1 if the named db cannot be found.
*/
SQLITE_PRIVATE int sqlite3FindDbName(sqlite3 *db, const char *zName){
  int i = -1;         /* Database number */
  if( zName ){
    Db *pDb;
    for(i=(db->nDb-1), pDb=&db->aDb[i]; i>=0; i--, pDb--){
      if( 0==sqlite3_stricmp(pDb->zDbSName, zName) ) break;
      /* "main" is always an acceptable alias for the primary database
      ** even if it has been renamed using SQLITE_DBCONFIG_MAINDBNAME. */
      if( i==0 && 0==sqlite3_stricmp("main", zName) ) break;
    }
  }
  return i;
}

/*
** The token *pName contains the name of a database (either "main" or
** "temp" or the name of an attached db). This routine returns the
** index of the named database in db->aDb[], or -1 if the named db
** does not exist.
*/
SQLITE_PRIVATE int sqlite3FindDb(sqlite3 *db, Token *pName){
  int i;                               /* Database number */
  char *zName;                         /* Name we are searching for */
  zName = sqlite3NameFromToken(db, pName);
  i = sqlite3FindDbName(db, zName);
  sqlite3DbFree(db, zName);
  return i;
}

/* The table or view or trigger name is passed to this routine via tokens
** pName1 and pName2. If the table name was fully qualified, for example:
**
** CREATE TABLE xxx.yyy (...);
**
** Then pName1 is set to "xxx" and pName2 "yyy". On the other hand if
** the table name is not fully qualified, i.e.:
**
** CREATE TABLE yyy(...);
**
** Then pName1 is set to "yyy" and pName2 is "".
**
** This routine sets the *ppUnqual pointer to point at the token (pName1 or
** pName2) that stores the unqualified table name.  The index of the
** database "xxx" is returned.

sqlite3.c  view on Meta::CPAN

  /* Estimate the average row size for the table and for all implied indices */
  estimateTableWidth(p);
  for(pIdx=p->pIndex; pIdx; pIdx=pIdx->pNext){
    estimateIndexWidth(pIdx);
  }

  /* If not initializing, then create a record for the new table
  ** in the schema table of the database.
  **
  ** If this is a TEMPORARY table, write the entry into the auxiliary
  ** file instead of into the main database file.
  */
  if( !db->init.busy ){
    int n;
    Vdbe *v;
    char *zType;    /* "view" or "table" */
    char *zType2;   /* "VIEW" or "TABLE" */
    char *zStmt;    /* Text of the CREATE TABLE or CREATE VIEW statement */

    v = sqlite3GetVdbe(pParse);
    if( NEVER(v==0) ) return;

    sqlite3VdbeAddOp1(v, OP_Close, 0);

    /*
    ** Initialize zType for the new view or table.
    */
    if( IsOrdinaryTable(p) ){
      /* A regular table */
      zType = "table";
      zType2 = "TABLE";
#ifndef SQLITE_OMIT_VIEW
    }else{
      /* A view */
      zType = "view";
      zType2 = "VIEW";
#endif
    }

    /* If this is a CREATE TABLE xx AS SELECT ..., execute the SELECT
    ** statement to populate the new table. The root-page number for the
    ** new table is in register pParse->u1.cr.regRoot.
    **
    ** Once the SELECT has been coded by sqlite3Select(), it is in a
    ** suitable state to query for the column names and types to be used
    ** by the new table.
    **
    ** A shared-cache write-lock is not required to write to the new table,
    ** as a schema-lock must have already been obtained to create it. Since
    ** a schema-lock excludes all other database users, the write-lock would
    ** be redundant.
    */
    if( pSelect ){
      SelectDest dest;    /* Where the SELECT should store results */
      int regYield;       /* Register holding co-routine entry-point */
      int addrTop;        /* Top of the co-routine */
      int regRec;         /* A record to be insert into the new table */
      int regRowid;       /* Rowid of the next row to insert */
      int addrInsLoop;    /* Top of the loop for inserting rows */
      Table *pSelTab;     /* A table that describes the SELECT results */
      int iCsr;           /* Write cursor on the new table */

      if( IN_SPECIAL_PARSE ){
        pParse->rc = SQLITE_ERROR;
        pParse->nErr++;
        return;
      }
      iCsr = pParse->nTab++;
      regYield = ++pParse->nMem;
      regRec = ++pParse->nMem;
      regRowid = ++pParse->nMem;
      sqlite3MayAbort(pParse);
      assert( pParse->isCreate );
      sqlite3VdbeAddOp3(v, OP_OpenWrite, iCsr, pParse->u1.cr.regRoot, iDb);
      sqlite3VdbeChangeP5(v, OPFLAG_P2ISREG);
      addrTop = sqlite3VdbeCurrentAddr(v) + 1;
      sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
      if( pParse->nErr ) return;
      pSelTab = sqlite3ResultSetOfSelect(pParse, pSelect, SQLITE_AFF_BLOB);
      if( pSelTab==0 ) return;
      assert( p->aCol==0 );
      p->nCol = p->nNVCol = pSelTab->nCol;
      p->aCol = pSelTab->aCol;
      pSelTab->nCol = 0;
      pSelTab->aCol = 0;
      sqlite3DeleteTable(db, pSelTab);
      sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
      sqlite3Select(pParse, pSelect, &dest);
      if( pParse->nErr ) return;
      sqlite3VdbeEndCoroutine(v, regYield);
      sqlite3VdbeJumpHere(v, addrTop - 1);
      addrInsLoop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
      VdbeCoverage(v);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, dest.iSdst, dest.nSdst, regRec);
      sqlite3TableAffinity(v, p, 0);
      sqlite3VdbeAddOp2(v, OP_NewRowid, iCsr, regRowid);
      sqlite3VdbeAddOp3(v, OP_Insert, iCsr, regRec, regRowid);
      sqlite3VdbeGoto(v, addrInsLoop);
      sqlite3VdbeJumpHere(v, addrInsLoop);
      sqlite3VdbeAddOp1(v, OP_Close, iCsr);
    }

    /* Compute the complete text of the CREATE statement */
    if( pSelect ){
      zStmt = createTableStmt(db, p);
    }else{
      Token *pEnd2 = tabOpts ? &pParse->sLastToken : pEnd;
      n = (int)(pEnd2->z - pParse->sNameToken.z);
      if( pEnd2->z[0]!=';' ) n += pEnd2->n;
      zStmt = sqlite3MPrintf(db,
          "CREATE %s %.*s", zType2, n, pParse->sNameToken.z
      );
    }

    /* A slot for the record has already been allocated in the
    ** schema table.  We just need to update that slot with all
    ** the information we've collected.
    */
    assert( pParse->isCreate );
    sqlite3NestedParse(pParse,
      "UPDATE %Q." LEGACY_SCHEMA_TABLE

sqlite3.c  view on Meta::CPAN

#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
/*
** The Table structure pTable is really a VIEW.  Fill in the names of
** the columns of the view in the pTable structure.  Return non-zero if
** there are errors.  If an error is seen an error message is left
** in pParse->zErrMsg.
*/
static SQLITE_NOINLINE int viewGetColumnNames(Parse *pParse, Table *pTable){
  Table *pSelTab;   /* A fake table from which we get the result set */
  Select *pSel;     /* Copy of the SELECT that implements the view */
  int nErr = 0;     /* Number of errors encountered */
  sqlite3 *db = pParse->db;  /* Database connection for malloc errors */
#ifndef SQLITE_OMIT_VIRTUALTABLE
  int rc;
#endif
#ifndef SQLITE_OMIT_AUTHORIZATION
  sqlite3_xauth xAuth;       /* Saved xAuth pointer */
#endif

  assert( pTable );

#ifndef SQLITE_OMIT_VIRTUALTABLE
  if( IsVirtual(pTable) ){
    db->nSchemaLock++;
    rc = sqlite3VtabCallConnect(pParse, pTable);
    db->nSchemaLock--;
    return rc;
  }
#endif

#ifndef SQLITE_OMIT_VIEW
  /* A positive nCol means the columns names for this view are
  ** already known.  This routine is not called unless either the
  ** table is virtual or nCol is zero.
  */
  assert( pTable->nCol<=0 );

  /* A negative nCol is a special marker meaning that we are currently
  ** trying to compute the column names.  If we enter this routine with
  ** a negative nCol, it means two or more views form a loop, like this:
  **
  **     CREATE VIEW one AS SELECT * FROM two;
  **     CREATE VIEW two AS SELECT * FROM one;
  **
  ** Actually, the error above is now caught prior to reaching this point.
  ** But the following test is still important as it does come up
  ** in the following:
  **
  **     CREATE TABLE main.ex1(a);
  **     CREATE TEMP VIEW ex1 AS SELECT a FROM ex1;
  **     SELECT * FROM temp.ex1;
  */
  if( pTable->nCol<0 ){
    sqlite3ErrorMsg(pParse, "view %s is circularly defined", pTable->zName);
    return 1;
  }
  assert( pTable->nCol>=0 );

  /* If we get this far, it means we need to compute the table names.
  ** Note that the call to sqlite3ResultSetOfSelect() will expand any
  ** "*" elements in the results set of the view and will assign cursors
  ** to the elements of the FROM clause.  But we do not want these changes
  ** to be permanent.  So the computation is done on a copy of the SELECT
  ** statement that defines the view.
  */
  assert( IsView(pTable) );
  pSel = sqlite3SelectDup(db, pTable->u.view.pSelect, 0);
  if( pSel ){
    u8 eParseMode = pParse->eParseMode;
    int nTab = pParse->nTab;
    int nSelect = pParse->nSelect;
    pParse->eParseMode = PARSE_MODE_NORMAL;
    sqlite3SrcListAssignCursors(pParse, pSel->pSrc);
    pTable->nCol = -1;
    DisableLookaside;
#ifndef SQLITE_OMIT_AUTHORIZATION
    xAuth = db->xAuth;
    db->xAuth = 0;
    pSelTab = sqlite3ResultSetOfSelect(pParse, pSel, SQLITE_AFF_NONE);
    db->xAuth = xAuth;
#else
    pSelTab = sqlite3ResultSetOfSelect(pParse, pSel, SQLITE_AFF_NONE);
#endif
    pParse->nTab = nTab;
    pParse->nSelect = nSelect;
    if( pSelTab==0 ){
      pTable->nCol = 0;
      nErr++;
    }else if( pTable->pCheck ){
      /* CREATE VIEW name(arglist) AS ...
      ** The names of the columns in the table are taken from
      ** arglist which is stored in pTable->pCheck.  The pCheck field
      ** normally holds CHECK constraints on an ordinary table, but for
      ** a VIEW it holds the list of column names.
      */
      sqlite3ColumnsFromExprList(pParse, pTable->pCheck,
                                 &pTable->nCol, &pTable->aCol);
      if( pParse->nErr==0
       && pTable->nCol==pSel->pEList->nExpr
      ){
        assert( db->mallocFailed==0 );
        sqlite3SubqueryColumnTypes(pParse, pTable, pSel, SQLITE_AFF_NONE);
      }
    }else{
      /* CREATE VIEW name AS...  without an argument list.  Construct
      ** the column names from the SELECT statement that defines the view.
      */
      assert( pTable->aCol==0 );
      pTable->nCol = pSelTab->nCol;
      pTable->aCol = pSelTab->aCol;
      pTable->tabFlags |= (pSelTab->tabFlags & COLFLAG_NOINSERT);
      pSelTab->nCol = 0;
      pSelTab->aCol = 0;
      assert( sqlite3SchemaMutexHeld(db, 0, pTable->pSchema) );
    }
    pTable->nNVCol = pTable->nCol;
    sqlite3DeleteTable(db, pSelTab);
    sqlite3SelectDelete(db, pSel);
    EnableLookaside;
    pParse->eParseMode = eParseMode;
  } else {

sqlite3.c  view on Meta::CPAN


  assert( sqlite3SchemaMutexHeld(db, 0, p->pSchema) );
  pNextTo = (FKey *)sqlite3HashInsert(&p->pSchema->fkeyHash,
      pFKey->zTo, (void *)pFKey
  );
  if( pNextTo==pFKey ){
    sqlite3OomFault(db);
    goto fk_end;
  }
  if( pNextTo ){
    assert( pNextTo->pPrevTo==0 );
    pFKey->pNextTo = pNextTo;
    pNextTo->pPrevTo = pFKey;
  }

  /* Link the foreign key to the table as the last step.
  */
  assert( IsOrdinaryTable(p) );
  p->u.tab.pFKey = pFKey;
  pFKey = 0;

fk_end:
  sqlite3DbFree(db, pFKey);
#endif /* !defined(SQLITE_OMIT_FOREIGN_KEY) */
  sqlite3ExprListDelete(db, pFromCol);
  sqlite3ExprListDelete(db, pToCol);
}

/*
** This routine is called when an INITIALLY IMMEDIATE or INITIALLY DEFERRED
** clause is seen as part of a foreign key definition.  The isDeferred
** parameter is 1 for INITIALLY DEFERRED and 0 for INITIALLY IMMEDIATE.
** The behavior of the most recently created foreign key is adjusted
** accordingly.
*/
SQLITE_PRIVATE void sqlite3DeferForeignKey(Parse *pParse, int isDeferred){
#ifndef SQLITE_OMIT_FOREIGN_KEY
  Table *pTab;
  FKey *pFKey;
  if( (pTab = pParse->pNewTable)==0 ) return;
  if( NEVER(!IsOrdinaryTable(pTab)) ) return;
  if( (pFKey = pTab->u.tab.pFKey)==0 ) return;
  assert( isDeferred==0 || isDeferred==1 ); /* EV: R-30323-21917 */
  pFKey->isDeferred = (u8)isDeferred;
#endif
}

/*
** Generate code that will erase and refill index *pIdx.  This is
** used to initialize a newly created index or to recompute the
** content of an index in response to a REINDEX command.
**
** if memRootPage is not negative, it means that the index is newly
** created.  The register specified by memRootPage contains the
** root page number of the index.  If memRootPage is negative, then
** the index already exists and must be cleared before being refilled and
** the root page number of the index is taken from pIndex->tnum.
*/
static void sqlite3RefillIndex(Parse *pParse, Index *pIndex, int memRootPage){
  Table *pTab = pIndex->pTable;  /* The table that is indexed */
  int iTab = pParse->nTab++;     /* Btree cursor used for pTab */
  int iIdx = pParse->nTab++;     /* Btree cursor used for pIndex */
  int iSorter;                   /* Cursor opened by OpenSorter (if in use) */
  int addr1;                     /* Address of top of loop */
  int addr2;                     /* Address to jump to for next iteration */
  Pgno tnum;                     /* Root page of index */
  int iPartIdxLabel;             /* Jump to this label to skip a row */
  Vdbe *v;                       /* Generate code into this virtual machine */
  KeyInfo *pKey;                 /* KeyInfo for index */
  int regRecord;                 /* Register holding assembled index record */
  sqlite3 *db = pParse->db;      /* The database connection */
  int iDb = sqlite3SchemaToIndex(db, pIndex->pSchema);

#ifndef SQLITE_OMIT_AUTHORIZATION
  if( sqlite3AuthCheck(pParse, SQLITE_REINDEX, pIndex->zName, 0,
      db->aDb[iDb].zDbSName ) ){
    return;
  }
#endif

  /* Require a write-lock on the table to perform this operation */
  sqlite3TableLock(pParse, iDb, pTab->tnum, 1, pTab->zName);

  v = sqlite3GetVdbe(pParse);
  if( v==0 ) return;
  if( memRootPage>=0 ){
    tnum = (Pgno)memRootPage;
  }else{
    tnum = pIndex->tnum;
  }
  pKey = sqlite3KeyInfoOfIndex(pParse, pIndex);
  assert( pKey!=0 || pParse->nErr );

  /* Open the sorter cursor if we are to use one. */
  iSorter = pParse->nTab++;
  sqlite3VdbeAddOp4(v, OP_SorterOpen, iSorter, 0, pIndex->nKeyCol, (char*)
                    sqlite3KeyInfoRef(pKey), P4_KEYINFO);

  /* Open the table. Loop through all rows of the table, inserting index
  ** records into the sorter. */
  sqlite3OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
  addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0); VdbeCoverage(v);
  regRecord = sqlite3GetTempReg(pParse);
  sqlite3MultiWrite(pParse);

  sqlite3GenerateIndexKey(pParse,pIndex,iTab,regRecord,0,&iPartIdxLabel,0,0);
  sqlite3VdbeAddOp2(v, OP_SorterInsert, iSorter, regRecord);
  sqlite3ResolvePartIdxLabel(pParse, iPartIdxLabel);
  sqlite3VdbeAddOp2(v, OP_Next, iTab, addr1+1); VdbeCoverage(v);
  sqlite3VdbeJumpHere(v, addr1);
  if( memRootPage<0 ) sqlite3VdbeAddOp2(v, OP_Clear, tnum, iDb);
  sqlite3VdbeAddOp4(v, OP_OpenWrite, iIdx, (int)tnum, iDb,
                    (char *)pKey, P4_KEYINFO);
  sqlite3VdbeChangeP5(v, OPFLAG_BULKCSR|((memRootPage>=0)?OPFLAG_P2ISREG:0));

  addr1 = sqlite3VdbeAddOp2(v, OP_SorterSort, iSorter, 0); VdbeCoverage(v);
  if( IsUniqueIndex(pIndex) ){
    int j2 = sqlite3VdbeGoto(v, 1);
    addr2 = sqlite3VdbeCurrentAddr(v);
    sqlite3VdbeVerifyAbortable(v, OE_Abort);
    sqlite3VdbeAddOp4Int(v, OP_SorterCompare, iSorter, j2, regRecord,
                         pIndex->nKeyCol); VdbeCoverage(v);
    sqlite3UniqueConstraint(pParse, OE_Abort, pIndex);
    sqlite3VdbeJumpHere(v, j2);
  }else{
    /* Most CREATE INDEX and REINDEX statements that are not UNIQUE can not
    ** abort. The exception is if one of the indexed expressions contains a
    ** user function that throws an exception when it is evaluated. But the
    ** overhead of adding a statement journal to a CREATE INDEX statement is
    ** very small (since most of the pages written do not contain content that
    ** needs to be restored if the statement aborts), so we call
    ** sqlite3MayAbort() for all CREATE INDEX statements.  */
    sqlite3MayAbort(pParse);
    addr2 = sqlite3VdbeCurrentAddr(v);
  }
  sqlite3VdbeAddOp3(v, OP_SorterData, iSorter, regRecord, iIdx);
  if( !pIndex->bAscKeyBug ){
    /* This OP_SeekEnd opcode makes index insert for a REINDEX go much
    ** faster by avoiding unnecessary seeks.  But the optimization does
    ** not work for UNIQUE constraint indexes on WITHOUT ROWID tables
    ** with DESC primary keys, since those indexes have there keys in
    ** a different order from the main table.
    ** See ticket: https://sqlite.org/src/info/bba7b69f9849b5bf
    */
    sqlite3VdbeAddOp1(v, OP_SeekEnd, iIdx);
  }
  sqlite3VdbeAddOp2(v, OP_IdxInsert, iIdx, regRecord);
  sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
  sqlite3ReleaseTempReg(pParse, regRecord);
  sqlite3VdbeAddOp2(v, OP_SorterNext, iSorter, addr2); VdbeCoverage(v);
  sqlite3VdbeJumpHere(v, addr1);

  sqlite3VdbeAddOp1(v, OP_Close, iTab);
  sqlite3VdbeAddOp1(v, OP_Close, iIdx);

sqlite3.c  view on Meta::CPAN

      for(i=0; i<pPk->nKeyCol; i++){
        Expr *p;
        assert( pPk->aiColumn[i]>=0 && pPk->aiColumn[i]<pTab->nCol );
        p = sqlite3Expr(db, TK_ID, pTab->aCol[pPk->aiColumn[i]].zCnName);
        pEList = sqlite3ExprListAppend(pParse, pEList, p);
      }
      pLhs = sqlite3PExpr(pParse, TK_VECTOR, 0, 0);
      if( pLhs ){
        pLhs->x.pList = sqlite3ExprListDup(db, pEList, 0);
      }
    }
  }

  /* duplicate the FROM clause as it is needed by both the DELETE/UPDATE tree
  ** and the SELECT subtree. */
  pSrc->a[0].pSTab = 0;
  pSelectSrc = sqlite3SrcListDup(db, pSrc, 0);
  pSrc->a[0].pSTab = pTab;
  if( pSrc->a[0].fg.isIndexedBy ){
    assert( pSrc->a[0].fg.isCte==0 );
    pSrc->a[0].u2.pIBIndex = 0;
    pSrc->a[0].fg.isIndexedBy = 0;
    sqlite3DbFree(db, pSrc->a[0].u1.zIndexedBy);
  }else if( pSrc->a[0].fg.isCte ){
    pSrc->a[0].u2.pCteUse->nUse++;
  }

  /* generate the SELECT expression tree. */
  pSelect = sqlite3SelectNew(pParse, pEList, pSelectSrc, pWhere, 0 ,0,
      pOrderBy,0,pLimit
  );

  /* now generate the new WHERE rowid IN clause for the DELETE/UPDATE */
  pInClause = sqlite3PExpr(pParse, TK_IN, pLhs, 0);
  sqlite3PExprAddSelect(pParse, pInClause, pSelect);
  return pInClause;
}
#endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) */
       /*      && !defined(SQLITE_OMIT_SUBQUERY) */

/*
** Generate code for a DELETE FROM statement.
**
**     DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL;
**                 \________/       \________________/
**                  pTabList              pWhere
*/
SQLITE_PRIVATE void sqlite3DeleteFrom(
  Parse *pParse,         /* The parser context */
  SrcList *pTabList,     /* The table from which we should delete things */
  Expr *pWhere,          /* The WHERE clause.  May be null */
  ExprList *pOrderBy,    /* ORDER BY clause. May be null */
  Expr *pLimit           /* LIMIT clause. May be null */
){
  Vdbe *v;               /* The virtual database engine */
  Table *pTab;           /* The table from which records will be deleted */
  int i;                 /* Loop counter */
  WhereInfo *pWInfo;     /* Information about the WHERE clause */
  Index *pIdx;           /* For looping over indices of the table */
  int iTabCur;           /* Cursor number for the table */
  int iDataCur = 0;      /* VDBE cursor for the canonical data source */
  int iIdxCur = 0;       /* Cursor number of the first index */
  int nIdx;              /* Number of indices */
  sqlite3 *db;           /* Main database structure */
  AuthContext sContext;  /* Authorization context */
  NameContext sNC;       /* Name context to resolve expressions in */
  int iDb;               /* Database number */
  int memCnt = 0;        /* Memory cell used for change counting */
  int rcauth;            /* Value returned by authorization callback */
  int eOnePass;          /* ONEPASS_OFF or _SINGLE or _MULTI */
  int aiCurOnePass[2];   /* The write cursors opened by WHERE_ONEPASS */
  u8 *aToOpen = 0;       /* Open cursor iTabCur+j if aToOpen[j] is true */
  Index *pPk;            /* The PRIMARY KEY index on the table */
  int iPk = 0;           /* First of nPk registers holding PRIMARY KEY value */
  i16 nPk = 1;           /* Number of columns in the PRIMARY KEY */
  int iKey;              /* Memory cell holding key of row to be deleted */
  i16 nKey;              /* Number of memory cells in the row key */
  int iEphCur = 0;       /* Ephemeral table holding all primary key values */
  int iRowSet = 0;       /* Register for rowset of rows to delete */
  int addrBypass = 0;    /* Address of jump over the delete logic */
  int addrLoop = 0;      /* Top of the delete loop */
  int addrEphOpen = 0;   /* Instruction to open the Ephemeral table */
  int bComplex;          /* True if there are triggers or FKs or
                         ** subqueries in the WHERE clause */

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* True if attempting to delete from a view */
  Trigger *pTrigger;           /* List of table triggers, if required */
#endif

  memset(&sContext, 0, sizeof(sContext));
  db = pParse->db;
  assert( db->pParse==pParse );
  if( pParse->nErr ){
    goto delete_from_cleanup;
  }
  assert( db->mallocFailed==0 );
  assert( pTabList->nSrc==1 );

  /* Locate the table which we want to delete.  This table has to be
  ** put in an SrcList structure because some of the subroutines we
  ** will be calling are designed to work with multiple tables and expect
  ** an SrcList* parameter instead of just a Table* parameter.
  */
  pTab = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 )  goto delete_from_cleanup;

  /* Figure out if we have any triggers and if the table being
  ** deleted from is a view
  */
#ifndef SQLITE_OMIT_TRIGGER
  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
  isView = IsView(pTab);
#else
# define pTrigger 0
# define isView 0
#endif
  bComplex = pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0);
#ifdef SQLITE_OMIT_VIEW
# undef isView
# define isView 0
#endif

#if TREETRACE_ENABLED
  if( sqlite3TreeTrace & 0x10000 ){
    sqlite3TreeViewLine(0, "In sqlite3Delete() at %s:%d", __FILE__, __LINE__);
    sqlite3TreeViewDelete(pParse->pWith, pTabList, pWhere,
                          pOrderBy, pLimit, pTrigger);
  }
#endif

#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
  if( !isView ){
    pWhere = sqlite3LimitWhere(
        pParse, pTabList, pWhere, pOrderBy, pLimit, "DELETE"
    );
    pOrderBy = 0;
    pLimit = 0;
  }
#endif

  /* If pTab is really a view, make sure it has been initialized.
  */
  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
    goto delete_from_cleanup;
  }

  if( sqlite3IsReadOnly(pParse, pTab, pTrigger) ){
    goto delete_from_cleanup;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb<db->nDb );
  rcauth = sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0,
                            db->aDb[iDb].zDbSName);
  assert( rcauth==SQLITE_OK || rcauth==SQLITE_DENY || rcauth==SQLITE_IGNORE );
  if( rcauth==SQLITE_DENY ){
    goto delete_from_cleanup;
  }
  assert(!isView || pTrigger);

  /* Assign cursor numbers to the table and all its indices.
  */
  assert( pTabList->nSrc==1 );
  iTabCur = pTabList->a[0].iCursor = pParse->nTab++;
  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
    pParse->nTab++;
  }

  /* Start the view context
  */
  if( isView ){
    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
  }

  /* Begin generating code.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ){
    goto delete_from_cleanup;
  }
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, bComplex, iDb);

  /* If we are trying to delete from a view, realize that view into
  ** an ephemeral table.
  */
#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
  if( isView ){
    sqlite3MaterializeView(pParse, pTab,
        pWhere, pOrderBy, pLimit, iTabCur
    );
    iDataCur = iIdxCur = iTabCur;
    pOrderBy = 0;
    pLimit = 0;
  }
#endif

  /* Resolve the column names in the WHERE clause.
  */
  memset(&sNC, 0, sizeof(sNC));
  sNC.pParse = pParse;
  sNC.pSrcList = pTabList;
  if( sqlite3ResolveExprNames(&sNC, pWhere) ){
    goto delete_from_cleanup;
  }

  /* Initialize the counter of the number of rows deleted, if
  ** we are counting rows.
  */
  if( (db->flags & SQLITE_CountRows)!=0
   && !pParse->nested
   && !pParse->pTriggerTab
   && !pParse->bReturning
  ){
    memCnt = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, memCnt);
  }

#ifndef SQLITE_OMIT_TRUNCATE_OPTIMIZATION
  /* Special case: A DELETE without a WHERE clause deletes everything.
  ** It is easier just to erase the whole table. Prior to version 3.6.5,

sqlite3.c  view on Meta::CPAN

    if( pWInfo==0 ) goto delete_from_cleanup;
    eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
    assert( IsVirtual(pTab)==0 || eOnePass!=ONEPASS_MULTI );
    assert( IsVirtual(pTab) || bComplex || eOnePass!=ONEPASS_OFF
            || OptimizationDisabled(db, SQLITE_OnePass) );
    if( eOnePass!=ONEPASS_SINGLE ) sqlite3MultiWrite(pParse);
    if( sqlite3WhereUsesDeferredSeek(pWInfo) ){
      sqlite3VdbeAddOp1(v, OP_FinishSeek, iTabCur);
    }

    /* Keep track of the number of rows to be deleted */
    if( memCnt ){
      sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
    }

    /* Extract the rowid or primary key for the current row */
    if( pPk ){
      for(i=0; i<nPk; i++){
        assert( pPk->aiColumn[i]>=0 );
        sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur,
                                        pPk->aiColumn[i], iPk+i);
      }
      iKey = iPk;
    }else{
      iKey = ++pParse->nMem;
      sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur, -1, iKey);
    }

    if( eOnePass!=ONEPASS_OFF ){
      /* For ONEPASS, no need to store the rowid/primary-key. There is only
      ** one, so just keep it in its register(s) and fall through to the
      ** delete code.  */
      nKey = nPk; /* OP_Found will use an unpacked key */
      aToOpen = sqlite3DbMallocRawNN(db, nIdx+2);
      if( aToOpen==0 ){
        sqlite3WhereEnd(pWInfo);
        goto delete_from_cleanup;
      }
      memset(aToOpen, 1, nIdx+1);
      aToOpen[nIdx+1] = 0;
      if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iTabCur] = 0;
      if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iTabCur] = 0;
      if( addrEphOpen ) sqlite3VdbeChangeToNoop(v, addrEphOpen);
      addrBypass = sqlite3VdbeMakeLabel(pParse);
    }else{
      if( pPk ){
        /* Add the PK key for this row to the temporary table */
        iKey = ++pParse->nMem;
        nKey = 0;   /* Zero tells OP_Found to use a composite key */
        sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, iKey,
            sqlite3IndexAffinityStr(pParse->db, pPk), nPk);
        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iEphCur, iKey, iPk, nPk);
      }else{
        /* Add the rowid of the row to be deleted to the RowSet */
        nKey = 1;  /* OP_DeferredSeek always uses a single rowid */
        sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, iKey);
      }
      sqlite3WhereEnd(pWInfo);
    }

    /* Unless this is a view, open cursors for the table we are
    ** deleting from and all its indices. If this is a view, then the
    ** only effect this statement has is to fire the INSTEAD OF
    ** triggers.
    */
    if( !isView ){
      int iAddrOnce = 0;
      if( eOnePass==ONEPASS_MULTI ){
        iAddrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
      }
      testcase( IsVirtual(pTab) );
      sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, OPFLAG_FORDELETE,
                                 iTabCur, aToOpen, &iDataCur, &iIdxCur);
      assert( pPk || IsVirtual(pTab) || iDataCur==iTabCur );
      assert( pPk || IsVirtual(pTab) || iIdxCur==iDataCur+1 );
      if( eOnePass==ONEPASS_MULTI ){
        sqlite3VdbeJumpHereOrPopInst(v, iAddrOnce);
      }
    }

    /* Set up a loop over the rowids/primary-keys that were found in the
    ** where-clause loop above.
    */
    if( eOnePass!=ONEPASS_OFF ){
      assert( nKey==nPk );  /* OP_Found will use an unpacked key */
      if( !IsVirtual(pTab) && aToOpen[iDataCur-iTabCur] ){
        assert( pPk!=0 || IsView(pTab) );
        sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, addrBypass, iKey, nKey);
        VdbeCoverage(v);
      }
    }else if( pPk ){
      addrLoop = sqlite3VdbeAddOp1(v, OP_Rewind, iEphCur); VdbeCoverage(v);
      if( IsVirtual(pTab) ){
        sqlite3VdbeAddOp3(v, OP_Column, iEphCur, 0, iKey);
      }else{
        sqlite3VdbeAddOp2(v, OP_RowData, iEphCur, iKey);
      }
      assert( nKey==0 );  /* OP_Found will use a composite key */
    }else{
      addrLoop = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, 0, iKey);
      VdbeCoverage(v);
      assert( nKey==1 );
    }

    /* Delete the row */
#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( IsVirtual(pTab) ){
      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
      sqlite3VtabMakeWritable(pParse, pTab);
      assert( eOnePass==ONEPASS_OFF || eOnePass==ONEPASS_SINGLE );
      sqlite3MayAbort(pParse);
      if( eOnePass==ONEPASS_SINGLE ){
        sqlite3VdbeAddOp1(v, OP_Close, iTabCur);
        if( sqlite3IsToplevel(pParse) ){
          pParse->isMultiWrite = 0;
        }
      }
      sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iKey, pVTab, P4_VTAB);
      sqlite3VdbeChangeP5(v, OE_Abort);
    }else
#endif

sqlite3.c  view on Meta::CPAN

          iKey, nKey, count, OE_Default, eOnePass, aiCurOnePass[1]);
    }

    /* End of the loop over all rowids/primary-keys. */
    if( eOnePass!=ONEPASS_OFF ){
      sqlite3VdbeResolveLabel(v, addrBypass);
      sqlite3WhereEnd(pWInfo);
    }else if( pPk ){
      sqlite3VdbeAddOp2(v, OP_Next, iEphCur, addrLoop+1); VdbeCoverage(v);
      sqlite3VdbeJumpHere(v, addrLoop);
    }else{
      sqlite3VdbeGoto(v, addrLoop);
      sqlite3VdbeJumpHere(v, addrLoop);
    }
  } /* End non-truncate path */

  /* Update the sqlite_sequence table by storing the content of the
  ** maximum rowid counter values recorded while inserting into
  ** autoincrement tables.
  */
  if( pParse->nested==0 && pParse->pTriggerTab==0 ){
    sqlite3AutoincrementEnd(pParse);
  }

  /* Return the number of rows that were deleted. If this routine is
  ** generating code because of a call to sqlite3NestedParse(), do not
  ** invoke the callback function.
  */
  if( memCnt ){
    sqlite3CodeChangeCount(v, memCnt, "rows deleted");
  }

delete_from_cleanup:
  sqlite3AuthContextPop(&sContext);
  sqlite3SrcListDelete(db, pTabList);
  sqlite3ExprDelete(db, pWhere);
#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT)
  sqlite3ExprListDelete(db, pOrderBy);
  sqlite3ExprDelete(db, pLimit);
#endif
  if( aToOpen ) sqlite3DbNNFreeNN(db, aToOpen);
  return;
}
/* Make sure "isView" and other macros defined above are undefined. Otherwise
** they may interfere with compilation of other functions in this file
** (or in another file, if this file becomes part of the amalgamation).  */
#ifdef isView
 #undef isView
#endif
#ifdef pTrigger
 #undef pTrigger
#endif

/*
** This routine generates VDBE code that causes a single row of a
** single table to be deleted.  Both the original table entry and
** all indices are removed.
**
** Preconditions:
**
**   1.  iDataCur is an open cursor on the btree that is the canonical data
**       store for the table.  (This will be either the table itself,
**       in the case of a rowid table, or the PRIMARY KEY index in the case
**       of a WITHOUT ROWID table.)
**
**   2.  Read/write cursors for all indices of pTab must be open as
**       cursor number iIdxCur+i for the i-th index.
**
**   3.  The primary key for the row to be deleted must be stored in a
**       sequence of nPk memory cells starting at iPk.  If nPk==0 that means
**       that a search record formed from OP_MakeRecord is contained in the
**       single memory location iPk.
**
** eMode:
**   Parameter eMode may be passed either ONEPASS_OFF (0), ONEPASS_SINGLE, or
**   ONEPASS_MULTI.  If eMode is not ONEPASS_OFF, then the cursor
**   iDataCur already points to the row to delete. If eMode is ONEPASS_OFF
**   then this function must seek iDataCur to the entry identified by iPk
**   and nPk before reading from it.
**
**   If eMode is ONEPASS_MULTI, then this call is being made as part
**   of a ONEPASS delete that affects multiple rows. In this case, if
**   iIdxNoSeek is a valid cursor number (>=0) and is not the same as
**   iDataCur, then its position should be preserved following the delete
**   operation. Or, if iIdxNoSeek is not a valid cursor number, the
**   position of iDataCur should be preserved instead.
**
** iIdxNoSeek:
**   If iIdxNoSeek is a valid cursor number (>=0) not equal to iDataCur,
**   then it identifies an index cursor (from within array of cursors
**   starting at iIdxCur) that already points to the index entry to be deleted.
**   Except, this optimization is disabled if there are BEFORE triggers since
**   the trigger body might have moved the cursor.
*/
SQLITE_PRIVATE void sqlite3GenerateRowDelete(
  Parse *pParse,     /* Parsing context */
  Table *pTab,       /* Table containing the row to be deleted */
  Trigger *pTrigger, /* List of triggers to (potentially) fire */
  int iDataCur,      /* Cursor from which column data is extracted */
  int iIdxCur,       /* First index cursor */
  int iPk,           /* First memory cell containing the PRIMARY KEY */
  i16 nPk,           /* Number of PRIMARY KEY memory cells */
  u8 count,          /* If non-zero, increment the row change counter */
  u8 onconf,         /* Default ON CONFLICT policy for triggers */
  u8 eMode,          /* ONEPASS_OFF, _SINGLE, or _MULTI.  See above */
  int iIdxNoSeek     /* Cursor number of cursor that does not need seeking */
){
  Vdbe *v = pParse->pVdbe;        /* Vdbe */
  int iOld = 0;                   /* First register in OLD.* array */
  int iLabel;                     /* Label resolved to end of generated code */
  u8 opSeek;                      /* Seek opcode */

  /* Vdbe is guaranteed to have been allocated by this stage. */
  assert( v );
  VdbeModuleComment((v, "BEGIN: GenRowDel(%d,%d,%d,%d)",
                         iDataCur, iIdxCur, iPk, (int)nPk));

  /* Seek cursor iCur to the row to delete. If this row no longer exists
  ** (this can happen if a trigger program has already deleted it), do
  ** not attempt to delete it or fire any DELETE triggers.  */
  iLabel = sqlite3VdbeMakeLabel(pParse);
  opSeek = HasRowid(pTab) ? OP_NotExists : OP_NotFound;
  if( eMode==ONEPASS_OFF ){
    sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk);
    VdbeCoverageIf(v, opSeek==OP_NotExists);
    VdbeCoverageIf(v, opSeek==OP_NotFound);
  }

  /* If there are any triggers to fire, allocate a range of registers to
  ** use for the old.* references in the triggers.  */
  if( sqlite3FkRequired(pParse, pTab, 0, 0) || pTrigger ){
    u32 mask;                     /* Mask of OLD.* columns in use */
    int iCol;                     /* Iterator used while populating OLD.* */
    int addrStart;                /* Start of BEFORE trigger programs */

    /* TODO: Could use temporary registers here. Also could attempt to
    ** avoid copying the contents of the rowid register.  */
    mask = sqlite3TriggerColmask(
        pParse, pTrigger, 0, 0, TRIGGER_BEFORE|TRIGGER_AFTER, pTab, onconf
    );
    mask |= sqlite3FkOldmask(pParse, pTab);
    iOld = pParse->nMem+1;
    pParse->nMem += (1 + pTab->nCol);

    /* Populate the OLD.* pseudo-table register array. These values will be
    ** used by any BEFORE and AFTER triggers that exist.  */
    sqlite3VdbeAddOp2(v, OP_Copy, iPk, iOld);
    for(iCol=0; iCol<pTab->nCol; iCol++){
      testcase( mask!=0xffffffff && iCol==31 );
      testcase( mask!=0xffffffff && iCol==32 );
      if( mask==0xffffffff || (iCol<=31 && (mask & MASKBIT32(iCol))!=0) ){
        int kk = sqlite3TableColumnToStorage(pTab, iCol);
        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, iCol, iOld+kk+1);
      }
    }

    /* Invoke BEFORE DELETE trigger programs. */
    addrStart = sqlite3VdbeCurrentAddr(v);
    sqlite3CodeRowTrigger(pParse, pTrigger,
        TK_DELETE, 0, TRIGGER_BEFORE, pTab, iOld, onconf, iLabel
    );

    /* If any BEFORE triggers were coded, then seek the cursor to the
    ** row to be deleted again. It may be that the BEFORE triggers moved
    ** the cursor or already deleted the row that the cursor was
    ** pointing to.
    **
    ** Also disable the iIdxNoSeek optimization since the BEFORE trigger
    ** may have moved that cursor.
    */
    if( addrStart<sqlite3VdbeCurrentAddr(v) ){
      sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk);
      VdbeCoverageIf(v, opSeek==OP_NotExists);
      VdbeCoverageIf(v, opSeek==OP_NotFound);
      testcase( iIdxNoSeek>=0 );
      iIdxNoSeek = -1;
    }

    /* Do FK processing. This call checks that any FK constraints that
    ** refer to this table (i.e. constraints attached to other tables)
    ** are not violated by deleting this row.  */
    sqlite3FkCheck(pParse, pTab, iOld, 0, 0, 0);
  }

  /* Delete the index and table entries. Skip this step if pTab is really
  ** a view (in which case the only effect of the DELETE statement is to
  ** fire the INSTEAD OF triggers).
  **
  ** If variable 'count' is non-zero, then this OP_Delete instruction should
  ** invoke the update-hook. The pre-update-hook, on the other hand should
  ** be invoked unless table pTab is a system table. The difference is that
  ** the update-hook is not invoked for rows removed by REPLACE, but the
  ** pre-update-hook is.
  */
  if( !IsView(pTab) ){
    u8 p5 = 0;
    sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur,0,iIdxNoSeek);
    sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, (count?OPFLAG_NCHANGE:0));
    if( pParse->nested==0 || 0==sqlite3_stricmp(pTab->zName, "sqlite_stat1") ){
      sqlite3VdbeAppendP4(v, (char*)pTab, P4_TABLE);
    }
    if( eMode!=ONEPASS_OFF ){
      sqlite3VdbeChangeP5(v, OPFLAG_AUXDELETE);
    }
    if( iIdxNoSeek>=0 && iIdxNoSeek!=iDataCur ){
      sqlite3VdbeAddOp1(v, OP_Delete, iIdxNoSeek);
    }
    if( eMode==ONEPASS_MULTI ) p5 |= OPFLAG_SAVEPOSITION;
    sqlite3VdbeChangeP5(v, p5);
  }

  /* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to
  ** handle rows (possibly in other tables) that refer via a foreign key
  ** to the row just deleted. */
  sqlite3FkActions(pParse, pTab, 0, iOld, 0, 0);

  /* Invoke AFTER DELETE trigger programs. */
  if( pTrigger ){
    sqlite3CodeRowTrigger(pParse, pTrigger,
        TK_DELETE, 0, TRIGGER_AFTER, pTab, iOld, onconf, iLabel
    );
  }

  /* Jump here if the row had already been deleted before any BEFORE
  ** trigger programs were invoked. Or if a trigger program throws a
  ** RAISE(IGNORE) exception.  */
  sqlite3VdbeResolveLabel(v, iLabel);
  VdbeModuleComment((v, "END: GenRowDel()"));
}

/*
** This routine generates VDBE code that causes the deletion of all
** index entries associated with a single row of a single table, pTab
**
** Preconditions:
**
**   1.  A read/write cursor "iDataCur" must be open on the canonical storage
**       btree for the table pTab.  (This will be either the table itself
**       for rowid tables or to the primary key index for WITHOUT ROWID
**       tables.)
**
**   2.  Read/write cursors for all indices of pTab must be open as
**       cursor number iIdxCur+i for the i-th index.  (The pTab->pIndex
**       index is the 0-th index.)
**
**   3.  The "iDataCur" cursor must be already be positioned on the row
**       that is to be deleted.
*/
SQLITE_PRIVATE void sqlite3GenerateRowIndexDelete(
  Parse *pParse,     /* Parsing and code generating context */
  Table *pTab,       /* Table containing the row to be deleted */
  int iDataCur,      /* Cursor of table holding data. */
  int iIdxCur,       /* First index cursor */
  int *aRegIdx,      /* Only delete if aRegIdx!=0 && aRegIdx[i]>0 */
  int iIdxNoSeek     /* Do not delete from this cursor */
){
  int i;             /* Index loop counter */
  int r1 = -1;       /* Register holding an index key */
  int iPartIdxLabel; /* Jump destination for skipping partial index entries */
  Index *pIdx;       /* Current index */
  Index *pPrior = 0; /* Prior index */
  Vdbe *v;           /* The prepared statement under construction */
  Index *pPk;        /* PRIMARY KEY index, or NULL for rowid tables */

  v = pParse->pVdbe;
  pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
  for(i=0, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
    assert( iIdxCur+i!=iDataCur || pPk==pIdx );
    if( aRegIdx!=0 && aRegIdx[i]==0 ) continue;
    if( pIdx==pPk ) continue;
    if( iIdxCur+i==iIdxNoSeek ) continue;
    VdbeModuleComment((v, "GenRowIdxDel for %s", pIdx->zName));
    r1 = sqlite3GenerateIndexKey(pParse, pIdx, iDataCur, 0, 1,
        &iPartIdxLabel, pPrior, r1);
    sqlite3VdbeAddOp3(v, OP_IdxDelete, iIdxCur+i, r1,
        pIdx->uniqNotNull ? pIdx->nKeyCol : pIdx->nColumn);
    sqlite3VdbeChangeP5(v, 1);  /* Cause IdxDelete to error if no entry found */
    sqlite3ResolvePartIdxLabel(pParse, iPartIdxLabel);
    pPrior = pIdx;
  }
}

/*
** Generate code that will assemble an index key and stores it in register
** regOut.  The key with be for index pIdx which is an index on pTab.
** iCur is the index of a cursor open on the pTab table and pointing to
** the entry that needs indexing.  If pTab is a WITHOUT ROWID table, then
** iCur must be the cursor of the PRIMARY KEY index.
**
** Return a register number which is the first in a block of
** registers that holds the elements of the index key.  The
** block of registers has already been deallocated by the time
** this routine returns.
**
** If *piPartIdxLabel is not NULL, fill it in with a label and jump
** to that label if pIdx is a partial index that should be skipped.
** The label should be resolved using sqlite3ResolvePartIdxLabel().
** A partial index should be skipped if its WHERE clause evaluates
** to false or null.  If pIdx is not a partial index, *piPartIdxLabel
** will be set to zero which is an empty label that is ignored by
** sqlite3ResolvePartIdxLabel().
**
** The pPrior and regPrior parameters are used to implement a cache to
** avoid unnecessary register loads.  If pPrior is not NULL, then it is
** a pointer to a different index for which an index key has just been
** computed into register regPrior.  If the current pIdx index is generating
** its key into the same sequence of registers and if pPrior and pIdx share
** a column in common, then the register corresponding to that column already
** holds the correct value and the loading of that register is skipped.
** This optimization is helpful when doing a DELETE or an INTEGRITY_CHECK
** on a table with multiple indices, and especially with the ROWID or
** PRIMARY KEY columns of the index.
*/
SQLITE_PRIVATE int sqlite3GenerateIndexKey(
  Parse *pParse,       /* Parsing context */
  Index *pIdx,         /* The index for which to generate a key */
  int iDataCur,        /* Cursor number from which to take column data */
  int regOut,          /* Put the new key into this register if not 0 */
  int prefixOnly,      /* Compute only a unique prefix of the key */
  int *piPartIdxLabel, /* OUT: Jump to this label to skip partial index */
  Index *pPrior,       /* Previously generated index key */
  int regPrior         /* Register holding previous generated key */
){
  Vdbe *v = pParse->pVdbe;
  int j;
  int regBase;
  int nCol;

  if( piPartIdxLabel ){
    if( pIdx->pPartIdxWhere ){
      *piPartIdxLabel = sqlite3VdbeMakeLabel(pParse);
      pParse->iSelfTab = iDataCur + 1;
      sqlite3ExprIfFalseDup(pParse, pIdx->pPartIdxWhere, *piPartIdxLabel,
                            SQLITE_JUMPIFNULL);
      pParse->iSelfTab = 0;
      pPrior = 0; /* Ticket a9efb42811fa41ee 2019-11-02;
                  ** pPartIdxWhere may have corrupted regPrior registers */
    }else{
      *piPartIdxLabel = 0;
    }
  }
  nCol = (prefixOnly && pIdx->uniqNotNull) ? pIdx->nKeyCol : pIdx->nColumn;
  regBase = sqlite3GetTempRange(pParse, nCol);
  if( pPrior && (regBase!=regPrior || pPrior->pPartIdxWhere) ) pPrior = 0;
  for(j=0; j<nCol; j++){
    if( pPrior
     && pPrior->aiColumn[j]==pIdx->aiColumn[j]
     && pPrior->aiColumn[j]!=XN_EXPR

sqlite3.c  view on Meta::CPAN

   && !pParse->pToplevel
   && !pParse->isMultiWrite
  ){
    /* Special case: If this is an INSERT statement that will insert exactly
    ** one row into the table, raise a constraint immediately instead of
    ** incrementing a counter. This is necessary as the VM code is being
    ** generated for will not open a statement transaction.  */
    assert( nIncr==1 );
    sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_FOREIGNKEY,
        OE_Abort, 0, P4_STATIC, P5_ConstraintFK);
  }else{
    if( nIncr>0 && pFKey->isDeferred==0 ){
      sqlite3MayAbort(pParse);
    }
    sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
  }

  sqlite3VdbeResolveLabel(v, iOk);
  sqlite3VdbeAddOp1(v, OP_Close, iCur);
}


/*
** Return an Expr object that refers to a memory register corresponding
** to column iCol of table pTab.
**
** regBase is the first of an array of register that contains the data
** for pTab.  regBase itself holds the rowid.  regBase+1 holds the first
** column.  regBase+2 holds the second column, and so forth.
*/
static Expr *exprTableRegister(
  Parse *pParse,     /* Parsing and code generating context */
  Table *pTab,       /* The table whose content is at r[regBase]... */
  int regBase,       /* Contents of table pTab */
  i16 iCol           /* Which column of pTab is desired */
){
  Expr *pExpr;
  Column *pCol;
  const char *zColl;
  sqlite3 *db = pParse->db;

  pExpr = sqlite3Expr(db, TK_REGISTER, 0);
  if( pExpr ){
    if( iCol>=0 && iCol!=pTab->iPKey ){
      pCol = &pTab->aCol[iCol];
      pExpr->iTable = regBase + sqlite3TableColumnToStorage(pTab,iCol) + 1;
      pExpr->affExpr = pCol->affinity;
      zColl = sqlite3ColumnColl(pCol);
      if( zColl==0 ) zColl = db->pDfltColl->zName;
      pExpr = sqlite3ExprAddCollateString(pParse, pExpr, zColl);
    }else{
      pExpr->iTable = regBase;
      pExpr->affExpr = SQLITE_AFF_INTEGER;
    }
  }
  return pExpr;
}

/*
** Return an Expr object that refers to column iCol of table pTab which
** has cursor iCur.
*/
static Expr *exprTableColumn(
  sqlite3 *db,      /* The database connection */
  Table *pTab,      /* The table whose column is desired */
  int iCursor,      /* The open cursor on the table */
  i16 iCol          /* The column that is wanted */
){
  Expr *pExpr = sqlite3Expr(db, TK_COLUMN, 0);
  if( pExpr ){
    assert( ExprUseYTab(pExpr) );
    pExpr->y.pTab = pTab;
    pExpr->iTable = iCursor;
    pExpr->iColumn = iCol;
  }
  return pExpr;
}

/*
** This function is called to generate code executed when a row is deleted
** from the parent table of foreign key constraint pFKey and, if pFKey is
** deferred, when a row is inserted into the same table. When generating
** code for an SQL UPDATE operation, this function may be called twice -
** once to "delete" the old row and once to "insert" the new row.
**
** Parameter nIncr is passed -1 when inserting a row (as this may decrease
** the number of FK violations in the db) or +1 when deleting one (as this
** may increase the number of FK constraint problems).
**
** The code generated by this function scans through the rows in the child
** table that correspond to the parent table row being deleted or inserted.
** For each child row found, one of the following actions is taken:
**
**   Operation | FK type   | Action taken
**   --------------------------------------------------------------------------
**   DELETE      immediate   Increment the "immediate constraint counter".
**
**   INSERT      immediate   Decrement the "immediate constraint counter".
**
**   DELETE      deferred    Increment the "deferred constraint counter".
**
**   INSERT      deferred    Decrement the "deferred constraint counter".
**
** These operations are identified in the comment at the top of this file
** (fkey.c) as "I.2" and "D.2".
*/
static void fkScanChildren(
  Parse *pParse,                  /* Parse context */
  SrcList *pSrc,                  /* The child table to be scanned */
  Table *pTab,                    /* The parent table */
  Index *pIdx,                    /* Index on parent covering the foreign key */
  FKey *pFKey,                    /* The foreign key linking pSrc to pTab */
  int *aiCol,                     /* Map from pIdx cols to child table cols */
  int regData,                    /* Parent row data starts here */
  int nIncr                       /* Amount to increment deferred counter by */
){
  sqlite3 *db = pParse->db;       /* Database handle */
  int i;                          /* Iterator variable */
  Expr *pWhere = 0;               /* WHERE clause to scan with */
  NameContext sNameContext;       /* Context used to resolve WHERE clause */
  WhereInfo *pWInfo;              /* Context used by sqlite3WhereXXX() */
  int iFkIfZero = 0;              /* Address of OP_FkIfZero */
  Vdbe *v = sqlite3GetVdbe(pParse);

  assert( pIdx==0 || pIdx->pTable==pTab );
  assert( pIdx==0 || pIdx->nKeyCol==pFKey->nCol );

sqlite3.c  view on Meta::CPAN


    /* Find the parent table of this foreign key. Also find a unique index
    ** on the parent key columns in the parent table. If either of these
    ** schema items cannot be located, set an error in pParse and return
    ** early.  */
    if( pParse->disableTriggers ){
      pTo = sqlite3FindTable(db, pFKey->zTo, zDb);
    }else{
      pTo = sqlite3LocateTable(pParse, 0, pFKey->zTo, zDb);
    }
    if( !pTo || sqlite3FkLocateIndex(pParse, pTo, pFKey, &pIdx, &aiFree) ){
      assert( isIgnoreErrors==0 || (regOld!=0 && regNew==0) );
      if( !isIgnoreErrors || db->mallocFailed ) return;
      if( pTo==0 ){
        /* If isIgnoreErrors is true, then a table is being dropped. In this
        ** case SQLite runs a "DELETE FROM xxx" on the table being dropped
        ** before actually dropping it in order to check FK constraints.
        ** If the parent table of an FK constraint on the current table is
        ** missing, behave as if it is empty. i.e. decrement the relevant
        ** FK counter for each row of the current table with non-NULL keys.
        */
        Vdbe *v = sqlite3GetVdbe(pParse);
        int iJump = sqlite3VdbeCurrentAddr(v) + pFKey->nCol + 1;
        for(i=0; i<pFKey->nCol; i++){
          int iFromCol, iReg;
          iFromCol = pFKey->aCol[i].iFrom;
          iReg = sqlite3TableColumnToStorage(pFKey->pFrom,iFromCol) + regOld+1;
          sqlite3VdbeAddOp2(v, OP_IsNull, iReg, iJump); VdbeCoverage(v);
        }
        sqlite3VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, -1);
      }
      continue;
    }
    assert( pFKey->nCol==1 || (aiFree && pIdx) );

    if( aiFree ){
      aiCol = aiFree;
    }else{
      iCol = pFKey->aCol[0].iFrom;
      aiCol = &iCol;
    }
    for(i=0; i<pFKey->nCol; i++){
      if( aiCol[i]==pTab->iPKey ){
        aiCol[i] = -1;
      }
      assert( pIdx==0 || pIdx->aiColumn[i]>=0 );
#ifndef SQLITE_OMIT_AUTHORIZATION
      /* Request permission to read the parent key columns. If the
      ** authorization callback returns SQLITE_IGNORE, behave as if any
      ** values read from the parent table are NULL. */
      if( db->xAuth ){
        int rcauth;
        char *zCol = pTo->aCol[pIdx ? pIdx->aiColumn[i] : pTo->iPKey].zCnName;
        rcauth = sqlite3AuthReadCol(pParse, pTo->zName, zCol, iDb);
        bIgnore = (rcauth==SQLITE_IGNORE);
      }
#endif
    }

    /* Take a shared-cache advisory read-lock on the parent table. Allocate
    ** a cursor to use to search the unique index on the parent key columns
    ** in the parent table.  */
    sqlite3TableLock(pParse, iDb, pTo->tnum, 0, pTo->zName);
    pParse->nTab++;

    if( regOld!=0 ){
      /* A row is being removed from the child table. Search for the parent.
      ** If the parent does not exist, removing the child row resolves an
      ** outstanding foreign key constraint violation. */
      fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regOld, -1, bIgnore);
    }
    if( regNew!=0 && !isSetNullAction(pParse, pFKey) ){
      /* A row is being added to the child table. If a parent row cannot
      ** be found, adding the child row has violated the FK constraint.
      **
      ** If this operation is being performed as part of a trigger program
      ** that is actually a "SET NULL" action belonging to this very
      ** foreign key, then omit this scan altogether. As all child key
      ** values are guaranteed to be NULL, it is not possible for adding
      ** this row to cause an FK violation.  */
      fkLookupParent(pParse, iDb, pTo, pIdx, pFKey, aiCol, regNew, +1, bIgnore);
    }

    sqlite3DbFree(db, aiFree);
  }

  /* Loop through all the foreign key constraints that refer to this table.
  ** (the "child" constraints) */
  for(pFKey = sqlite3FkReferences(pTab); pFKey; pFKey=pFKey->pNextTo){
    Index *pIdx = 0;              /* Foreign key index for pFKey */
    SrcList *pSrc;
    int *aiCol = 0;

    if( aChange && fkParentIsModified(pTab, pFKey, aChange, bChngRowid)==0 ){
      continue;
    }

    if( !pFKey->isDeferred && !(db->flags & SQLITE_DeferFKs)
     && !pParse->pToplevel && !pParse->isMultiWrite
    ){
      assert( regOld==0 && regNew!=0 );
      /* Inserting a single row into a parent table cannot cause (or fix)
      ** an immediate foreign key violation. So do nothing in this case.  */
      continue;
    }

    if( sqlite3FkLocateIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ){
      if( !isIgnoreErrors || db->mallocFailed ) return;
      continue;
    }
    assert( aiCol || pFKey->nCol==1 );

    /* Create a SrcList structure containing the child table.  We need the
    ** child table as a SrcList for sqlite3WhereBegin() */
    pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);
    if( pSrc ){
      SrcItem *pItem = pSrc->a;
      pItem->pSTab = pFKey->pFrom;
      pItem->zName = pFKey->pFrom->zName;
      pItem->pSTab->nTabRef++;
      pItem->iCursor = pParse->nTab++;

sqlite3.c  view on Meta::CPAN

  FKey *pFKey;                    /* Iterator variable */
  FKey *pNext;                    /* Copy of pFKey->pNextFrom */

  assert( IsOrdinaryTable(pTab) );
  assert( db!=0 );
  for(pFKey=pTab->u.tab.pFKey; pFKey; pFKey=pNext){
    assert( db==0 || sqlite3SchemaMutexHeld(db, 0, pTab->pSchema) );

    /* Remove the FK from the fkeyHash hash table. */
    if( db->pnBytesFreed==0 ){
      if( pFKey->pPrevTo ){
        pFKey->pPrevTo->pNextTo = pFKey->pNextTo;
      }else{
        const char *z = (pFKey->pNextTo ? pFKey->pNextTo->zTo : pFKey->zTo);
        sqlite3HashInsert(&pTab->pSchema->fkeyHash, z, pFKey->pNextTo);
      }
      if( pFKey->pNextTo ){
        pFKey->pNextTo->pPrevTo = pFKey->pPrevTo;
      }
    }

    /* EV: R-30323-21917 Each foreign key constraint in SQLite is
    ** classified as either immediate or deferred.
    */
    assert( pFKey->isDeferred==0 || pFKey->isDeferred==1 );

    /* Delete any triggers created to implement actions for this FK. */
#ifndef SQLITE_OMIT_TRIGGER
    fkTriggerDelete(db, pFKey->apTrigger[0]);
    fkTriggerDelete(db, pFKey->apTrigger[1]);
#endif

    pNext = pFKey->pNextFrom;
    sqlite3DbFree(db, pFKey);
  }
}
#endif /* ifndef SQLITE_OMIT_FOREIGN_KEY */

/************** End of fkey.c ************************************************/
/************** Begin file insert.c ******************************************/
/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
*/
/* #include "sqliteInt.h" */

/*
** Generate code that will
**
**   (1) acquire a lock for table pTab then
**   (2) open pTab as cursor iCur.
**
** If pTab is a WITHOUT ROWID table, then it is the PRIMARY KEY index
** for that table that is actually opened.
*/
SQLITE_PRIVATE void sqlite3OpenTable(
  Parse *pParse,  /* Generate code into this VDBE */
  int iCur,       /* The cursor number of the table */
  int iDb,        /* The database index in sqlite3.aDb[] */
  Table *pTab,    /* The table to be opened */
  int opcode      /* OP_OpenRead or OP_OpenWrite */
){
  Vdbe *v;
  assert( !IsVirtual(pTab) );
  assert( pParse->pVdbe!=0 );
  v = pParse->pVdbe;
  assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
  if( !pParse->db->noSharedCache ){
    sqlite3TableLock(pParse, iDb, pTab->tnum,
                     (opcode==OP_OpenWrite)?1:0, pTab->zName);
  }
  if( HasRowid(pTab) ){
    sqlite3VdbeAddOp4Int(v, opcode, iCur, pTab->tnum, iDb, pTab->nNVCol);
    VdbeComment((v, "%s", pTab->zName));
  }else{
    Index *pPk = sqlite3PrimaryKeyIndex(pTab);
    assert( pPk!=0 );
    assert( pPk->tnum==pTab->tnum || CORRUPT_DB );
    sqlite3VdbeAddOp3(v, opcode, iCur, pPk->tnum, iDb);
    sqlite3VdbeSetP4KeyInfo(pParse, pPk);
    VdbeComment((v, "%s", pTab->zName));
  }
}

/*
** Return a pointer to the column affinity string associated with index
** pIdx. A column affinity string has one character for each column in
** the table, according to the affinity of the column:
**
**  Character      Column affinity
**  ------------------------------
**  'A'            BLOB
**  'B'            TEXT
**  'C'            NUMERIC
**  'D'            INTEGER
**  'F'            REAL
**
** An extra 'D' is appended to the end of the string to cover the
** rowid that appears as the last column in every index.
**
** Memory for the buffer containing the column index affinity string
** is managed along with the rest of the Index structure. It will be
** released when sqlite3DeleteIndex() is called.
*/
static SQLITE_NOINLINE const char *computeIndexAffStr(sqlite3 *db, Index *pIdx){
  /* The first time a column affinity string for a particular index is
  ** required, it is allocated and populated here. It is then stored as
  ** a member of the Index structure for subsequent use.
  **
  ** The column affinity string will eventually be deleted by
  ** sqliteDeleteIndex() when the Index structure itself is cleaned
  ** up.
  */
  int n;
  Table *pTab = pIdx->pTable;
  pIdx->zColAff = (char *)sqlite3DbMallocRaw(0, pIdx->nColumn+1);
  if( !pIdx->zColAff ){
    sqlite3OomFault(db);

sqlite3.c  view on Meta::CPAN

*/
static int exprListIsConstant(Parse *pParse, ExprList *pRow){
  int ii;
  for(ii=0; ii<pRow->nExpr; ii++){
    if( 0==sqlite3ExprIsConstant(pParse, pRow->a[ii].pExpr) ) return 0;
  }
  return 1;
}

/*
** Return true if all expressions in the expression-list passed as the
** only argument are both constant and have no affinity.
*/
static int exprListIsNoAffinity(Parse *pParse, ExprList *pRow){
  int ii;
  if( exprListIsConstant(pParse,pRow)==0 ) return 0;
  for(ii=0; ii<pRow->nExpr; ii++){
    Expr *pExpr = pRow->a[ii].pExpr;
    assert( pExpr->op!=TK_RAISE );
    assert( pExpr->affExpr==0 );
    if( 0!=sqlite3ExprAffinity(pExpr) ) return 0;
  }
  return 1;

}

/*
** This function is called by the parser for the second and subsequent
** rows of a multi-row VALUES clause. Argument pLeft is the part of
** the VALUES clause already parsed, argument pRow is the vector of values
** for the new row. The Select object returned represents the complete
** VALUES clause, including the new row.
**
** There are two ways in which this may be achieved - by incremental
** coding of a co-routine (the "co-routine" method) or by returning a
** Select object equivalent to the following (the "UNION ALL" method):
**
**        "pLeft UNION ALL SELECT pRow"
**
** If the VALUES clause contains a lot of rows, this compound Select
** object may consume a lot of memory.
**
** When the co-routine method is used, each row that will be returned
** by the VALUES clause is coded into part of a co-routine as it is
** passed to this function. The returned Select object is equivalent to:
**
**     SELECT * FROM (
**       Select object to read co-routine
**     )
**
** The co-routine method is used in most cases. Exceptions are:
**
**    a) If the current statement has a WITH clause. This is to avoid
**       statements like:
**
**            WITH cte AS ( VALUES('x'), ('y') ... )
**            SELECT * FROM cte AS a, cte AS b;
**
**       This will not work, as the co-routine uses a hard-coded register
**       for its OP_Yield instructions, and so it is not possible for two
**       cursors to iterate through it concurrently.
**
**    b) The schema is currently being parsed (i.e. the VALUES clause is part
**       of a schema item like a VIEW or TRIGGER). In this case there is no VM
**       being generated when parsing is taking place, and so generating
**       a co-routine is not possible.
**
**    c) There are non-constant expressions in the VALUES clause (e.g.
**       the VALUES clause is part of a correlated sub-query).
**
**    d) One or more of the values in the first row of the VALUES clause
**       has an affinity (i.e. is a CAST expression). This causes problems
**       because the complex rules SQLite uses (see function
**       sqlite3SubqueryColumnTypes() in select.c) to determine the effective
**       affinity of such a column for all rows require access to all values in
**       the column simultaneously.
*/
SQLITE_PRIVATE Select *sqlite3MultiValues(Parse *pParse, Select *pLeft, ExprList *pRow){

  if( pParse->bHasWith                   /* condition (a) above */
   || pParse->db->init.busy              /* condition (b) above */
   || exprListIsConstant(pParse,pRow)==0 /* condition (c) above */
   || (pLeft->pSrc->nSrc==0 &&
       exprListIsNoAffinity(pParse,pLeft->pEList)==0) /* condition (d) above */
   || IN_SPECIAL_PARSE
  ){
    /* The co-routine method cannot be used. Fall back to UNION ALL. */
    Select *pSelect = 0;
    int f = SF_Values | SF_MultiValue;
    if( pLeft->pSrc->nSrc ){
      sqlite3MultiValuesEnd(pParse, pLeft);
      f = SF_Values;
    }else if( pLeft->pPrior ){
      /* In this case set the SF_MultiValue flag only if it was set on pLeft */
      f = (f & pLeft->selFlags);
    }
    pSelect = sqlite3SelectNew(pParse, pRow, 0, 0, 0, 0, 0, f, 0);
    pLeft->selFlags &= ~(u32)SF_MultiValue;
    if( pSelect ){
      pSelect->op = TK_ALL;
      pSelect->pPrior = pLeft;
      pLeft = pSelect;
    }
  }else{
    SrcItem *p = 0;               /* SrcItem that reads from co-routine */

    if( pLeft->pSrc->nSrc==0 ){
      /* Co-routine has not yet been started and the special Select object
      ** that accesses the co-routine has not yet been created. This block
      ** does both those things. */
      Vdbe *v = sqlite3GetVdbe(pParse);
      Select *pRet = sqlite3SelectNew(pParse, 0, 0, 0, 0, 0, 0, 0, 0);

      /* Ensure the database schema has been read. This is to ensure we have
      ** the correct text encoding.  */
      if( (pParse->db->mDbFlags & DBFLAG_SchemaKnownOk)==0 ){
        sqlite3ReadSchema(pParse);
      }

      if( pRet ){
        SelectDest dest;

sqlite3.c  view on Meta::CPAN

      }
    }else{
      p = &pLeft->pSrc->a[0];
      assert( !p->fg.isTabFunc && !p->fg.isIndexedBy );
      p->u1.nRow++;
    }

    if( pParse->nErr==0 ){
      Subquery *pSubq;
      assert( p!=0 );
      assert( p->fg.isSubquery );
      pSubq = p->u4.pSubq;
      assert( pSubq!=0 );
      assert( pSubq->pSelect!=0 );
      assert( pSubq->pSelect->pEList!=0 );
      if( pSubq->pSelect->pEList->nExpr!=pRow->nExpr ){
        sqlite3SelectWrongNumTermsError(pParse, pSubq->pSelect);
      }else{
        sqlite3ExprCodeExprList(pParse, pRow, pSubq->regResult, 0, 0);
        sqlite3VdbeAddOp1(pParse->pVdbe, OP_Yield, pSubq->regReturn);
      }
    }
    sqlite3ExprListDelete(pParse->db, pRow);
  }

  return pLeft;
}

/* Forward declaration */
static int xferOptimization(
  Parse *pParse,        /* Parser context */
  Table *pDest,         /* The table we are inserting into */
  Select *pSelect,      /* A SELECT statement to use as the data source */
  int onError,          /* How to handle constraint errors */
  int iDbDest           /* The database of pDest */
);

/*
** This routine is called to handle SQL of the following forms:
**
**    insert into TABLE (IDLIST) values(EXPRLIST),(EXPRLIST),...
**    insert into TABLE (IDLIST) select
**    insert into TABLE (IDLIST) default values
**
** The IDLIST following the table name is always optional.  If omitted,
** then a list of all (non-hidden) columns for the table is substituted.
** The IDLIST appears in the pColumn parameter.  pColumn is NULL if IDLIST
** is omitted.
**
** For the pSelect parameter holds the values to be inserted for the
** first two forms shown above.  A VALUES clause is really just short-hand
** for a SELECT statement that omits the FROM clause and everything else
** that follows.  If the pSelect parameter is NULL, that means that the
** DEFAULT VALUES form of the INSERT statement is intended.
**
** The code generated follows one of four templates.  For a simple
** insert with data coming from a single-row VALUES clause, the code executes
** once straight down through.  Pseudo-code follows (we call this
** the "1st template"):
**
**         open write cursor to <table> and its indices
**         put VALUES clause expressions into registers
**         write the resulting record into <table>
**         cleanup
**
** The three remaining templates assume the statement is of the form
**
**   INSERT INTO <table> SELECT ...
**
** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
** in other words if the SELECT pulls all columns from a single table
** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
** if <table2> and <table1> are distinct tables but have identical
** schemas, including all the same indices, then a special optimization
** is invoked that copies raw records from <table2> over to <table1>.
** See the xferOptimization() function for the implementation of this
** template.  This is the 2nd template.
**
**         open a write cursor to <table>
**         open read cursor on <table2>
**         transfer all records in <table2> over to <table>
**         close cursors
**         foreach index on <table>
**           open a write cursor on the <table> index
**           open a read cursor on the corresponding <table2> index
**           transfer all records from the read to the write cursors
**           close cursors
**         end foreach
**
** The 3rd template is for when the second template does not apply
** and the SELECT clause does not read from <table> at any time.
** The generated code follows this template:
**
**         X <- A
**         goto B
**      A: setup for the SELECT
**         loop over the rows in the SELECT
**           load values into registers R..R+n
**           yield X
**         end loop
**         cleanup after the SELECT
**         end-coroutine X
**      B: open write cursor to <table> and its indices
**      C: yield X, at EOF goto D
**         insert the select result into <table> from R..R+n
**         goto C
**      D: cleanup
**
** The 4th template is used if the insert statement takes its
** values from a SELECT but the data is being inserted into a table
** that is also read as part of the SELECT.  In the third form,
** we have to use an intermediate table to store the results of
** the select.  The template is like this:
**
**         X <- A
**         goto B
**      A: setup for the SELECT
**         loop over the tables in the SELECT
**           load value into register R..R+n
**           yield X
**         end loop
**         cleanup after the SELECT
**         end co-routine R
**      B: open temp table
**      L: yield X, at EOF goto M
**         insert row from R..R+n into temp table
**         goto L
**      M: open write cursor to <table> and its indices
**         rewind temp table
**      C: loop over rows of intermediate table
**           transfer values form intermediate table into <table>
**         end loop
**      D: cleanup
*/
SQLITE_PRIVATE void sqlite3Insert(
  Parse *pParse,        /* Parser context */
  SrcList *pTabList,    /* Name of table into which we are inserting */
  Select *pSelect,      /* A SELECT statement to use as the data source */
  IdList *pColumn,      /* Column names corresponding to IDLIST, or NULL. */
  int onError,          /* How to handle constraint errors */
  Upsert *pUpsert       /* ON CONFLICT clauses for upsert, or NULL */
){
  sqlite3 *db;          /* The main database structure */
  Table *pTab;          /* The table to insert into.  aka TABLE */
  int i, j;             /* Loop counters */
  Vdbe *v;              /* Generate code into this virtual machine */
  Index *pIdx;          /* For looping over indices of the table */
  int nColumn;          /* Number of columns in the data */
  int nHidden = 0;      /* Number of hidden columns if TABLE is virtual */
  int iDataCur = 0;     /* VDBE cursor that is the main data repository */
  int iIdxCur = 0;      /* First index cursor */
  int ipkColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
  int endOfLoop;        /* Label for the end of the insertion loop */
  int srcTab = 0;       /* Data comes from this temporary cursor if >=0 */
  int addrInsTop = 0;   /* Jump to label "D" */
  int addrCont = 0;     /* Top of insert loop. Label "C" in templates 3 and 4 */
  SelectDest dest;      /* Destination for SELECT on rhs of INSERT */
  int iDb;              /* Index of database holding TABLE */
  u8 useTempTable = 0;  /* Store SELECT results in intermediate table */
  u8 appendFlag = 0;    /* True if the insert is likely to be an append */
  u8 withoutRowid;      /* 0 for normal table.  1 for WITHOUT ROWID table */
  u8 bIdListInOrder;    /* True if IDLIST is in table order */
  ExprList *pList = 0;  /* List of VALUES() to be inserted  */
  int iRegStore;        /* Register in which to store next column */

  /* Register allocations */
  int regFromSelect = 0;/* Base register for data coming from SELECT */
  int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
  int regRowCount = 0;  /* Memory cell used for the row counter */
  int regIns;           /* Block of regs holding rowid+data being inserted */
  int regRowid;         /* registers holding insert rowid */
  int regData;          /* register holding first column to insert */
  int *aRegIdx = 0;     /* One register allocated to each index */
  int *aTabColMap = 0;  /* Mapping from pTab columns to pCol entries */

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                 /* True if attempting to insert into a view */
  Trigger *pTrigger;          /* List of triggers on pTab, if required */
  int tmask;                  /* Mask of trigger times */
#endif

  db = pParse->db;
  assert( db->pParse==pParse );
  if( pParse->nErr ){
    goto insert_cleanup;
  }
  assert( db->mallocFailed==0 );
  dest.iSDParm = 0;  /* Suppress a harmless compiler warning */

  /* If the Select object is really just a simple VALUES() list with a
  ** single row (the common case) then keep that one row of values
  ** and discard the other (unused) parts of the pSelect object
  */
  if( pSelect && (pSelect->selFlags & SF_Values)!=0 && pSelect->pPrior==0 ){
    pList = pSelect->pEList;
    pSelect->pEList = 0;
    sqlite3SelectDelete(db, pSelect);
    pSelect = 0;
  }

  /* Locate the table into which we will be inserting new information.
  */
  assert( pTabList->nSrc==1 );
  pTab = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 ){
    goto insert_cleanup;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb<db->nDb );
  if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0,
                       db->aDb[iDb].zDbSName) ){
    goto insert_cleanup;
  }
  withoutRowid = !HasRowid(pTab);

sqlite3.c  view on Meta::CPAN

      /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
      ** to generate a unique primary key value.
      */
      if( !appendFlag ){
        int addr1;
        if( !IsVirtual(pTab) ){
          addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regRowid); VdbeCoverage(v);
          sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
          sqlite3VdbeJumpHere(v, addr1);
        }else{
          addr1 = sqlite3VdbeCurrentAddr(v);
          sqlite3VdbeAddOp2(v, OP_IsNull, regRowid, addr1+2); VdbeCoverage(v);
        }
        sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid); VdbeCoverage(v);
      }
    }else if( IsVirtual(pTab) || withoutRowid ){
      sqlite3VdbeAddOp2(v, OP_Null, 0, regRowid);
    }else{
      sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
      appendFlag = 1;
    }
    autoIncStep(pParse, regAutoinc, regRowid);

#ifndef SQLITE_OMIT_GENERATED_COLUMNS
    /* Compute the new value for generated columns after all other
    ** columns have already been computed.  This must be done after
    ** computing the ROWID in case one of the generated columns
    ** is derived from the INTEGER PRIMARY KEY. */
    if( pTab->tabFlags & TF_HasGenerated ){
      sqlite3ComputeGeneratedColumns(pParse, regRowid+1, pTab);
    }
#endif

    /* Generate code to check constraints and generate index keys and
    ** do the insertion.
    */
#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( IsVirtual(pTab) ){
      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
      sqlite3VtabMakeWritable(pParse, pTab);
      sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns, pVTab, P4_VTAB);
      sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
      sqlite3MayAbort(pParse);
    }else
#endif
    {
      int isReplace = 0;/* Set to true if constraints may cause a replace */
      int bUseSeek;     /* True to use OPFLAG_SEEKRESULT */
      sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
          regIns, 0, ipkColumn>=0, onError, endOfLoop, &isReplace, 0, pUpsert
      );
      if( db->flags & SQLITE_ForeignKeys ){
        sqlite3FkCheck(pParse, pTab, 0, regIns, 0, 0);
      }

      /* Set the OPFLAG_USESEEKRESULT flag if either (a) there are no REPLACE
      ** constraints or (b) there are no triggers and this table is not a
      ** parent table in a foreign key constraint. It is safe to set the
      ** flag in the second case as if any REPLACE constraint is hit, an
      ** OP_Delete or OP_IdxDelete instruction will be executed on each
      ** cursor that is disturbed. And these instructions both clear the
      ** VdbeCursor.seekResult variable, disabling the OPFLAG_USESEEKRESULT
      ** functionality.  */
      bUseSeek = (isReplace==0 || !sqlite3VdbeHasSubProgram(v));
      sqlite3CompleteInsertion(pParse, pTab, iDataCur, iIdxCur,
          regIns, aRegIdx, 0, appendFlag, bUseSeek
      );
    }
#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
  }else if( pParse->bReturning ){
    /* If there is a RETURNING clause, populate the rowid register with
    ** constant value -1, in case one or more of the returned expressions
    ** refer to the "rowid" of the view.  */
    sqlite3VdbeAddOp2(v, OP_Integer, -1, regRowid);
#endif
  }

  /* Update the count of rows that are inserted
  */
  if( regRowCount ){
    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
  }

  if( pTrigger ){
    /* Code AFTER triggers */
    sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_AFTER,
        pTab, regData-2-pTab->nCol, onError, endOfLoop);
  }

  /* The bottom of the main insertion loop, if the data source
  ** is a SELECT statement.
  */
  sqlite3VdbeResolveLabel(v, endOfLoop);
  if( useTempTable ){
    sqlite3VdbeAddOp2(v, OP_Next, srcTab, addrCont); VdbeCoverage(v);
    sqlite3VdbeJumpHere(v, addrInsTop);
    sqlite3VdbeAddOp1(v, OP_Close, srcTab);
  }else if( pSelect ){
    sqlite3VdbeGoto(v, addrCont);
#ifdef SQLITE_DEBUG
    /* If we are jumping back to an OP_Yield that is preceded by an
    ** OP_ReleaseReg, set the p5 flag on the OP_Goto so that the
    ** OP_ReleaseReg will be included in the loop. */
    if( sqlite3VdbeGetOp(v, addrCont-1)->opcode==OP_ReleaseReg ){
      assert( sqlite3VdbeGetOp(v, addrCont)->opcode==OP_Yield );
      sqlite3VdbeChangeP5(v, 1);
    }
#endif
    sqlite3VdbeJumpHere(v, addrInsTop);
  }

#ifndef SQLITE_OMIT_XFER_OPT
insert_end:
#endif /* SQLITE_OMIT_XFER_OPT */
  /* Update the sqlite_sequence table by storing the content of the
  ** maximum rowid counter values recorded while inserting into
  ** autoincrement tables.
  */
  if( pParse->nested==0 && pParse->pTriggerTab==0 ){
    sqlite3AutoincrementEnd(pParse);
  }

sqlite3.c  view on Meta::CPAN

/* Return the next index from the list.  Return NULL when out of indexes */
static Index *indexIteratorNext(IndexIterator *pIter, int *pIx){
  if( pIter->eType ){
    int i = ++pIter->i;
    if( i>=pIter->u.ax.nIdx ){
      *pIx = i;
      return 0;
    }
    *pIx = pIter->u.ax.aIdx[i].ix;
    return pIter->u.ax.aIdx[i].p;
  }else{
    ++(*pIx);
    pIter->u.lx.pIdx = pIter->u.lx.pIdx->pNext;
    return pIter->u.lx.pIdx;
  }
}

/*
** Generate code to do constraint checks prior to an INSERT or an UPDATE
** on table pTab.
**
** The regNewData parameter is the first register in a range that contains
** the data to be inserted or the data after the update.  There will be
** pTab->nCol+1 registers in this range.  The first register (the one
** that regNewData points to) will contain the new rowid, or NULL in the
** case of a WITHOUT ROWID table.  The second register in the range will
** contain the content of the first table column.  The third register will
** contain the content of the second table column.  And so forth.
**
** The regOldData parameter is similar to regNewData except that it contains
** the data prior to an UPDATE rather than afterwards.  regOldData is zero
** for an INSERT.  This routine can distinguish between UPDATE and INSERT by
** checking regOldData for zero.
**
** For an UPDATE, the pkChng boolean is true if the true primary key (the
** rowid for a normal table or the PRIMARY KEY for a WITHOUT ROWID table)
** might be modified by the UPDATE.  If pkChng is false, then the key of
** the iDataCur content table is guaranteed to be unchanged by the UPDATE.
**
** For an INSERT, the pkChng boolean indicates whether or not the rowid
** was explicitly specified as part of the INSERT statement.  If pkChng
** is zero, it means that the either rowid is computed automatically or
** that the table is a WITHOUT ROWID table and has no rowid.  On an INSERT,
** pkChng will only be true if the INSERT statement provides an integer
** value for either the rowid column or its INTEGER PRIMARY KEY alias.
**
** The code generated by this routine will store new index entries into
** registers identified by aRegIdx[].  No index entry is created for
** indices where aRegIdx[i]==0.  The order of indices in aRegIdx[] is
** the same as the order of indices on the linked list of indices
** at pTab->pIndex.
**
** (2019-05-07) The generated code also creates a new record for the
** main table, if pTab is a rowid table, and stores that record in the
** register identified by aRegIdx[nIdx] - in other words in the first
** entry of aRegIdx[] past the last index.  It is important that the
** record be generated during constraint checks to avoid affinity changes
** to the register content that occur after constraint checks but before
** the new record is inserted.
**
** The caller must have already opened writeable cursors on the main
** table and all applicable indices (that is to say, all indices for which
** aRegIdx[] is not zero).  iDataCur is the cursor for the main table when
** inserting or updating a rowid table, or the cursor for the PRIMARY KEY
** index when operating on a WITHOUT ROWID table.  iIdxCur is the cursor
** for the first index in the pTab->pIndex list.  Cursors for other indices
** are at iIdxCur+N for the N-th element of the pTab->pIndex list.
**
** This routine also generates code to check constraints.  NOT NULL,
** CHECK, and UNIQUE constraints are all checked.  If a constraint fails,
** then the appropriate action is performed.  There are five possible
** actions: ROLLBACK, ABORT, FAIL, REPLACE, and IGNORE.
**
**  Constraint type  Action       What Happens
**  ---------------  ----------   ----------------------------------------
**  any              ROLLBACK     The current transaction is rolled back and
**                                sqlite3_step() returns immediately with a
**                                return code of SQLITE_CONSTRAINT.
**
**  any              ABORT        Back out changes from the current command
**                                only (do not do a complete rollback) then
**                                cause sqlite3_step() to return immediately
**                                with SQLITE_CONSTRAINT.
**
**  any              FAIL         Sqlite3_step() returns immediately with a
**                                return code of SQLITE_CONSTRAINT.  The
**                                transaction is not rolled back and any
**                                changes to prior rows are retained.
**
**  any              IGNORE       The attempt in insert or update the current
**                                row is skipped, without throwing an error.
**                                Processing continues with the next row.
**                                (There is an immediate jump to ignoreDest.)
**
**  NOT NULL         REPLACE      The NULL value is replace by the default
**                                value for that column.  If the default value
**                                is NULL, the action is the same as ABORT.
**
**  UNIQUE           REPLACE      The other row that conflicts with the row
**                                being inserted is removed.
**
**  CHECK            REPLACE      Illegal.  The results in an exception.
**
** Which action to take is determined by the overrideError parameter.
** Or if overrideError==OE_Default, then the pParse->onError parameter
** is used.  Or if pParse->onError==OE_Default then the onError value
** for the constraint is used.
*/
SQLITE_PRIVATE void sqlite3GenerateConstraintChecks(
  Parse *pParse,       /* The parser context */
  Table *pTab,         /* The table being inserted or updated */
  int *aRegIdx,        /* Use register aRegIdx[i] for index i.  0 for unused */
  int iDataCur,        /* Canonical data cursor (main table or PK index) */
  int iIdxCur,         /* First index cursor */
  int regNewData,      /* First register in a range holding values to insert */
  int regOldData,      /* Previous content.  0 for INSERTs */
  u8 pkChng,           /* Non-zero if the rowid or PRIMARY KEY changed */
  u8 overrideError,    /* Override onError to this if not OE_Default */
  int ignoreDest,      /* Jump to this label on an OE_Ignore resolution */
  int *pbMayReplace,   /* OUT: Set to true if constraint may cause a replace */
  int *aiChng,         /* column i is unchanged if aiChng[i]<0 */
  Upsert *pUpsert      /* ON CONFLICT clauses, if any.  NULL otherwise */
){
  Vdbe *v;             /* VDBE under construction */
  Index *pIdx;         /* Pointer to one of the indices */
  Index *pPk = 0;      /* The PRIMARY KEY index for WITHOUT ROWID tables */
  sqlite3 *db;         /* Database connection */
  int i;               /* loop counter */
  int ix;              /* Index loop counter */
  int nCol;            /* Number of columns */
  int onError;         /* Conflict resolution strategy */
  int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
  int nPkField;        /* Number of fields in PRIMARY KEY. 1 for ROWID tables */
  Upsert *pUpsertClause = 0;  /* The specific ON CONFLICT clause for pIdx */
  u8 isUpdate;           /* True if this is an UPDATE operation */
  u8 bAffinityDone = 0;  /* True if the OP_Affinity operation has been run */
  int upsertIpkReturn = 0; /* Address of Goto at end of IPK uniqueness check */
  int upsertIpkDelay = 0;  /* Address of Goto to bypass initial IPK check */
  int ipkTop = 0;        /* Top of the IPK uniqueness check */
  int ipkBottom = 0;     /* OP_Goto at the end of the IPK uniqueness check */
  /* Variables associated with retesting uniqueness constraints after
  ** replace triggers fire have run */
  int regTrigCnt;       /* Register used to count replace trigger invocations */
  int addrRecheck = 0;  /* Jump here to recheck all uniqueness constraints */
  int lblRecheckOk = 0; /* Each recheck jumps to this label if it passes */
  Trigger *pTrigger;    /* List of DELETE triggers on the table pTab */
  int nReplaceTrig = 0; /* Number of replace triggers coded */
  IndexIterator sIdxIter;  /* Index iterator */

  isUpdate = regOldData!=0;
  db = pParse->db;
  v = pParse->pVdbe;
  assert( v!=0 );
  assert( !IsView(pTab) );  /* This table is not a VIEW */
  nCol = pTab->nCol;

  /* pPk is the PRIMARY KEY index for WITHOUT ROWID tables and NULL for
  ** normal rowid tables.  nPkField is the number of key fields in the
  ** pPk index or 1 for a rowid table.  In other words, nPkField is the
  ** number of fields in the true primary key of the table. */
  if( HasRowid(pTab) ){
    pPk = 0;
    nPkField = 1;
  }else{
    pPk = sqlite3PrimaryKeyIndex(pTab);
    nPkField = pPk->nKeyCol;
  }

  /* Record that this module has started */
  VdbeModuleComment((v, "BEGIN: GenCnstCks(%d,%d,%d,%d,%d)",
                     iDataCur, iIdxCur, regNewData, regOldData, pkChng));

  /* Test all NOT NULL constraints.
  */

sqlite3.c  view on Meta::CPAN

    sqlite3VdbeJumpHere(v, ipkBottom);
  }

  /* Recheck all uniqueness constraints after replace triggers have run */
  testcase( regTrigCnt!=0 && nReplaceTrig==0 );
  assert( regTrigCnt!=0 || nReplaceTrig==0 );
  if( nReplaceTrig ){
    sqlite3VdbeAddOp2(v, OP_IfNot, regTrigCnt, lblRecheckOk);VdbeCoverage(v);
    if( !pPk ){
      if( isUpdate ){
        sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRecheck, regOldData);
        sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
        VdbeCoverage(v);
      }
      sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRecheck, regNewData);
      VdbeCoverage(v);
      sqlite3RowidConstraint(pParse, OE_Abort, pTab);
    }else{
      sqlite3VdbeGoto(v, addrRecheck);
    }
    sqlite3VdbeResolveLabel(v, lblRecheckOk);
  }

  /* Generate the table record */
  if( HasRowid(pTab) ){
    int regRec = aRegIdx[ix];
    sqlite3VdbeAddOp3(v, OP_MakeRecord, regNewData+1, pTab->nNVCol, regRec);
    sqlite3SetMakeRecordP5(v, pTab);
    if( !bAffinityDone ){
      sqlite3TableAffinity(v, pTab, 0);
    }
  }

  *pbMayReplace = seenReplace;
  VdbeModuleComment((v, "END: GenCnstCks(%d)", seenReplace));
}

#ifdef SQLITE_ENABLE_NULL_TRIM
/*
** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)
** to be the number of columns in table pTab that must not be NULL-trimmed.
**
** Or if no columns of pTab may be NULL-trimmed, leave P5 at zero.
*/
SQLITE_PRIVATE void sqlite3SetMakeRecordP5(Vdbe *v, Table *pTab){
  u16 i;

  /* Records with omitted columns are only allowed for schema format
  ** version 2 and later (SQLite version 3.1.4, 2005-02-20). */
  if( pTab->pSchema->file_format<2 ) return;

  for(i=pTab->nCol-1; i>0; i--){
    if( pTab->aCol[i].iDflt!=0 ) break;
    if( pTab->aCol[i].colFlags & COLFLAG_PRIMKEY ) break;
  }
  sqlite3VdbeChangeP5(v, i+1);
}
#endif

/*
** Table pTab is a WITHOUT ROWID table that is being written to. The cursor
** number is iCur, and register regData contains the new record for the
** PK index. This function adds code to invoke the pre-update hook,
** if one is registered.
*/
#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
static void codeWithoutRowidPreupdate(
  Parse *pParse,                  /* Parse context */
  Table *pTab,                    /* Table being updated */
  int iCur,                       /* Cursor number for table */
  int regData                     /* Data containing new record */
){
  Vdbe *v = pParse->pVdbe;
  int r = sqlite3GetTempReg(pParse);
  assert( !HasRowid(pTab) );
  assert( 0==(pParse->db->mDbFlags & DBFLAG_Vacuum) || CORRUPT_DB );
  sqlite3VdbeAddOp2(v, OP_Integer, 0, r);
  sqlite3VdbeAddOp4(v, OP_Insert, iCur, regData, r, (char*)pTab, P4_TABLE);
  sqlite3VdbeChangeP5(v, OPFLAG_ISNOOP);
  sqlite3ReleaseTempReg(pParse, r);
}
#else
# define codeWithoutRowidPreupdate(a,b,c,d)
#endif

/*
** This routine generates code to finish the INSERT or UPDATE operation
** that was started by a prior call to sqlite3GenerateConstraintChecks.
** A consecutive range of registers starting at regNewData contains the
** rowid and the content to be inserted.
**
** The arguments to this routine should be the same as the first six
** arguments to sqlite3GenerateConstraintChecks.
*/
SQLITE_PRIVATE void sqlite3CompleteInsertion(
  Parse *pParse,      /* The parser context */
  Table *pTab,        /* the table into which we are inserting */
  int iDataCur,       /* Cursor of the canonical data source */
  int iIdxCur,        /* First index cursor */
  int regNewData,     /* Range of content */
  int *aRegIdx,       /* Register used by each index.  0 for unused indices */
  int update_flags,   /* True for UPDATE, False for INSERT */
  int appendBias,     /* True if this is likely to be an append */
  int useSeekResult   /* True to set the USESEEKRESULT flag on OP_[Idx]Insert */
){
  Vdbe *v;            /* Prepared statements under construction */
  Index *pIdx;        /* An index being inserted or updated */
  u8 pik_flags;       /* flag values passed to the btree insert */
  int i;              /* Loop counter */

  assert( update_flags==0
       || update_flags==OPFLAG_ISUPDATE
       || update_flags==(OPFLAG_ISUPDATE|OPFLAG_SAVEPOSITION)
  );

  v = pParse->pVdbe;
  assert( v!=0 );
  assert( !IsView(pTab) );  /* This table is not a VIEW */
  for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    /* All REPLACE indexes are at the end of the list */
    assert( pIdx->onError!=OE_Replace
         || pIdx->pNext==0
         || pIdx->pNext->onError==OE_Replace );
    if( aRegIdx[i]==0 ) continue;
    if( pIdx->pPartIdxWhere ){
      sqlite3VdbeAddOp2(v, OP_IsNull, aRegIdx[i], sqlite3VdbeCurrentAddr(v)+2);
      VdbeCoverage(v);
    }
    pik_flags = (useSeekResult ? OPFLAG_USESEEKRESULT : 0);
    if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
      pik_flags |= OPFLAG_NCHANGE;
      pik_flags |= (update_flags & OPFLAG_SAVEPOSITION);
      if( update_flags==0 ){
        codeWithoutRowidPreupdate(pParse, pTab, iIdxCur+i, aRegIdx[i]);
      }
    }
    sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iIdxCur+i, aRegIdx[i],
                         aRegIdx[i]+1,
                         pIdx->uniqNotNull ? pIdx->nKeyCol: pIdx->nColumn);
    sqlite3VdbeChangeP5(v, pik_flags);
  }
  if( !HasRowid(pTab) ) return;
  if( pParse->nested ){
    pik_flags = 0;
  }else{
    pik_flags = OPFLAG_NCHANGE;
    pik_flags |= (update_flags?update_flags:OPFLAG_LASTROWID);
  }
  if( appendBias ){
    pik_flags |= OPFLAG_APPEND;
  }
  if( useSeekResult ){
    pik_flags |= OPFLAG_USESEEKRESULT;
  }
  sqlite3VdbeAddOp3(v, OP_Insert, iDataCur, aRegIdx[i], regNewData);
  if( !pParse->nested ){
    sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
  }
  sqlite3VdbeChangeP5(v, pik_flags);
}

/*
** Allocate cursors for the pTab table and all its indices and generate
** code to open and initialized those cursors.
**
** The cursor for the object that contains the complete data (normally
** the table itself, but the PRIMARY KEY index in the case of a WITHOUT
** ROWID table) is returned in *piDataCur.  The first index cursor is
** returned in *piIdxCur.  The number of indices is returned.
**
** Use iBase as the first cursor (either the *piDataCur for rowid tables
** or the first index for WITHOUT ROWID tables) if it is non-negative.
** If iBase is negative, then allocate the next available cursor.
**
** For a rowid table, *piDataCur will be exactly one less than *piIdxCur.
** For a WITHOUT ROWID table, *piDataCur will be somewhere in the range
** of *piIdxCurs, depending on where the PRIMARY KEY index appears on the
** pTab->pIndex list.
**
** If pTab is a virtual table, then this routine is a no-op and the
** *piDataCur and *piIdxCur values are left uninitialized.
*/
SQLITE_PRIVATE int sqlite3OpenTableAndIndices(
  Parse *pParse,   /* Parsing context */
  Table *pTab,     /* Table to be opened */
  int op,          /* OP_OpenRead or OP_OpenWrite */
  u8 p5,           /* P5 value for OP_Open* opcodes (except on WITHOUT ROWID) */
  int iBase,       /* Use this for the table cursor, if there is one */
  u8 *aToOpen,     /* If not NULL: boolean for each table and index */
  int *piDataCur,  /* Write the database source cursor number here */
  int *piIdxCur    /* Write the first index cursor number here */
){
  int i;
  int iDb;
  int iDataCur;
  Index *pIdx;
  Vdbe *v;

  assert( op==OP_OpenRead || op==OP_OpenWrite );
  assert( op==OP_OpenWrite || p5==0 );
  assert( piDataCur!=0 );
  assert( piIdxCur!=0 );
  if( IsVirtual(pTab) ){
    /* This routine is a no-op for virtual tables. Leave the output
    ** variables *piDataCur and *piIdxCur set to illegal cursor numbers
    ** for improved error detection. */
    *piDataCur = *piIdxCur = -999;
    return 0;
  }
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  v = pParse->pVdbe;
  assert( v!=0 );
  if( iBase<0 ) iBase = pParse->nTab;
  iDataCur = iBase++;
  *piDataCur = iDataCur;
  if( HasRowid(pTab) && (aToOpen==0 || aToOpen[0]) ){
    sqlite3OpenTable(pParse, iDataCur, iDb, pTab, op);
  }else if( pParse->db->noSharedCache==0 ){
    sqlite3TableLock(pParse, iDb, pTab->tnum, op==OP_OpenWrite, pTab->zName);
  }
  *piIdxCur = iBase;
  for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    int iIdxCur = iBase++;
    assert( pIdx->pSchema==pTab->pSchema );
    if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
      *piDataCur = iIdxCur;
      p5 = 0;
    }
    if( aToOpen==0 || aToOpen[i+1] ){
      sqlite3VdbeAddOp3(v, op, iIdxCur, pIdx->tnum, iDb);
      sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
      sqlite3VdbeChangeP5(v, p5);
      VdbeComment((v, "%s", pIdx->zName));
    }
  }
  if( iBase>pParse->nTab ) pParse->nTab = iBase;
  return i;
}


#ifdef SQLITE_TEST
/*
** The following global variable is incremented whenever the
** transfer optimization is used.  This is used for testing
** purposes only - to make sure the transfer optimization really
** is happening when it is supposed to.
*/
SQLITE_API int sqlite3_xferopt_count;
#endif /* SQLITE_TEST */


#ifndef SQLITE_OMIT_XFER_OPT
/*
** Check to see if index pSrc is compatible as a source of data
** for index pDest in an insert transfer optimization.  The rules
** for a compatible index:
**
**    *   The index is over the same set of columns
**    *   The same DESC and ASC markings occurs on all columns
**    *   The same onError processing (OE_Abort, OE_Ignore, etc)
**    *   The same collating sequence on each column
**    *   The index has the exact same WHERE clause
*/
static int xferCompatibleIndex(Index *pDest, Index *pSrc){
  int i;

sqlite3.c  view on Meta::CPAN

          iTab = cnt++;
        }else{
          iTab = cnt;
          for(pIdx=pTab->pIndex; ALWAYS(pIdx); pIdx=pIdx->pNext){
            if( IsPrimaryKeyIndex(pIdx) ) break;
            iTab++;
          }
        }
        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
          if( pIdx->pPartIdxWhere==0 ){
            addr = sqlite3VdbeAddOp3(v, OP_Eq, 8+cnt, 0, 8+iTab);
            VdbeCoverageNeverNull(v);
            sqlite3VdbeLoadString(v, 4, pIdx->zName);
            sqlite3VdbeAddOp3(v, OP_Concat, 4, 2, 3);
            integrityCheckResultRow(v);
            sqlite3VdbeJumpHere(v, addr);
          }
          cnt++;
        }
      }

      /* Make sure all the indices are constructed correctly.
      */
      for(x=sqliteHashFirst(pTbls); x; x=sqliteHashNext(x)){
        Table *pTab = sqliteHashData(x);
        Index *pIdx, *pPk;
        Index *pPrior = 0;      /* Previous index */
        int loopTop;
        int iDataCur, iIdxCur;
        int r1 = -1;
        int bStrict;            /* True for a STRICT table */
        int r2;                 /* Previous key for WITHOUT ROWID tables */
        int mxCol;              /* Maximum non-virtual column number */

        if( tableSkipIntegrityCheck(pTab,pObjTab) ) continue;
        if( !IsOrdinaryTable(pTab) ) continue;
        if( isQuick || HasRowid(pTab) ){
          pPk = 0;
          r2 = 0;
        }else{
          pPk = sqlite3PrimaryKeyIndex(pTab);
          r2 = sqlite3GetTempRange(pParse, pPk->nKeyCol);
          sqlite3VdbeAddOp3(v, OP_Null, 1, r2, r2+pPk->nKeyCol-1);
        }
        sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenRead, 0,
                                   1, 0, &iDataCur, &iIdxCur);
        /* reg[7] counts the number of entries in the table.
        ** reg[8+i] counts the number of entries in the i-th index
        */
        sqlite3VdbeAddOp2(v, OP_Integer, 0, 7);
        for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
          sqlite3VdbeAddOp2(v, OP_Integer, 0, 8+j); /* index entries counter */
        }
        assert( pParse->nMem>=8+j );
        assert( sqlite3NoTempsInRange(pParse,1,7+j) );
        sqlite3VdbeAddOp2(v, OP_Rewind, iDataCur, 0); VdbeCoverage(v);
        loopTop = sqlite3VdbeAddOp2(v, OP_AddImm, 7, 1);

        /* Fetch the right-most column from the table.  This will cause
        ** the entire record header to be parsed and sanity checked.  It
        ** will also prepopulate the cursor column cache that is used
        ** by the OP_IsType code, so it is a required step.
        */
        assert( !IsVirtual(pTab) );
        if( HasRowid(pTab) ){
          mxCol = -1;
          for(j=0; j<pTab->nCol; j++){
            if( (pTab->aCol[j].colFlags & COLFLAG_VIRTUAL)==0 ) mxCol++;
          }
          if( mxCol==pTab->iPKey ) mxCol--;
        }else{
          /* COLFLAG_VIRTUAL columns are not included in the WITHOUT ROWID
          ** PK index column-count, so there is no need to account for them
          ** in this case. */
          mxCol = sqlite3PrimaryKeyIndex(pTab)->nColumn-1;
        }
        if( mxCol>=0 ){
          sqlite3VdbeAddOp3(v, OP_Column, iDataCur, mxCol, 3);
          sqlite3VdbeTypeofColumn(v, 3);
        }

        if( !isQuick ){
          if( pPk ){
            /* Verify WITHOUT ROWID keys are in ascending order */
            int a1;
            char *zErr;
            a1 = sqlite3VdbeAddOp4Int(v, OP_IdxGT, iDataCur, 0,r2,pPk->nKeyCol);
            VdbeCoverage(v);
            sqlite3VdbeAddOp1(v, OP_IsNull, r2); VdbeCoverage(v);
            zErr = sqlite3MPrintf(db,
                   "row not in PRIMARY KEY order for %s",
                    pTab->zName);
            sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
            integrityCheckResultRow(v);
            sqlite3VdbeJumpHere(v, a1);
            sqlite3VdbeJumpHere(v, a1+1);
            for(j=0; j<pPk->nKeyCol; j++){
              sqlite3ExprCodeLoadIndexColumn(pParse, pPk, iDataCur, j, r2+j);
            }
          }
        }
        /* Verify datatypes for all columns:
        **
        **   (1) NOT NULL columns may not contain a NULL
        **   (2) Datatype must be exact for non-ANY columns in STRICT tables
        **   (3) Datatype for TEXT columns in non-STRICT tables must be
        **       NULL, TEXT, or BLOB.
        **   (4) Datatype for numeric columns in non-STRICT tables must not
        **       be a TEXT value that can be losslessly converted to numeric.
        */
        bStrict = (pTab->tabFlags & TF_Strict)!=0;
        for(j=0; j<pTab->nCol; j++){
          char *zErr;
          Column *pCol = pTab->aCol + j;  /* The column to be checked */
          int labelError;               /* Jump here to report an error */
          int labelOk;                  /* Jump here if all looks ok */
          int p1, p3, p4;               /* Operands to the OP_IsType opcode */
          int doTypeCheck;              /* Check datatypes (besides NOT NULL) */

          if( j==pTab->iPKey ) continue;
          if( bStrict ){

sqlite3.c  view on Meta::CPAN

    };
    int i;
    pParse->nMem = 2;
    for(i=0; i<db->nDb; i++){
      Btree *pBt;
      const char *zState = "unknown";
      int j;
      if( db->aDb[i].zDbSName==0 ) continue;
      pBt = db->aDb[i].pBt;
      if( pBt==0 || sqlite3BtreePager(pBt)==0 ){
        zState = "closed";
      }else if( sqlite3_file_control(db, i ? db->aDb[i].zDbSName : 0,
                                     SQLITE_FCNTL_LOCKSTATE, &j)==SQLITE_OK ){
         zState = azLockName[j];
      }
      sqlite3VdbeMultiLoad(v, 1, "ss", db->aDb[i].zDbSName, zState);
    }
    break;
  }
#endif

#if defined(SQLITE_ENABLE_CEROD)
  case PragTyp_ACTIVATE_EXTENSIONS: if( zRight ){
    if( sqlite3StrNICmp(zRight, "cerod-", 6)==0 ){
      sqlite3_activate_cerod(&zRight[6]);
    }
  }
  break;
#endif

  } /* End of the PRAGMA switch */

  /* The following block is a no-op unless SQLITE_DEBUG is defined. Its only
  ** purpose is to execute assert() statements to verify that if the
  ** PragFlg_NoColumns1 flag is set and the caller specified an argument
  ** to the PRAGMA, the implementation has not added any OP_ResultRow
  ** instructions to the VM.  */
  if( (pPragma->mPragFlg & PragFlg_NoColumns1) && zRight ){
    sqlite3VdbeVerifyNoResultRow(v);
  }

pragma_out:
  sqlite3DbFree(db, zLeft);
  sqlite3DbFree(db, zRight);
}
#ifndef SQLITE_OMIT_VIRTUALTABLE
/*****************************************************************************
** Implementation of an eponymous virtual table that runs a pragma.
**
*/
typedef struct PragmaVtab PragmaVtab;
typedef struct PragmaVtabCursor PragmaVtabCursor;
struct PragmaVtab {
  sqlite3_vtab base;        /* Base class.  Must be first */
  sqlite3 *db;              /* The database connection to which it belongs */
  const PragmaName *pName;  /* Name of the pragma */
  u8 nHidden;               /* Number of hidden columns */
  u8 iHidden;               /* Index of the first hidden column */
};
struct PragmaVtabCursor {
  sqlite3_vtab_cursor base; /* Base class.  Must be first */
  sqlite3_stmt *pPragma;    /* The pragma statement to run */
  sqlite_int64 iRowid;      /* Current rowid */
  char *azArg[2];           /* Value of the argument and schema */
};

/*
** Pragma virtual table module xConnect method.
*/
static int pragmaVtabConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  const PragmaName *pPragma = (const PragmaName*)pAux;
  PragmaVtab *pTab = 0;
  int rc;
  int i, j;
  char cSep = '(';
  StrAccum acc;
  char zBuf[200];

  UNUSED_PARAMETER(argc);
  UNUSED_PARAMETER(argv);
  sqlite3StrAccumInit(&acc, 0, zBuf, sizeof(zBuf), 0);
  sqlite3_str_appendall(&acc, "CREATE TABLE x");
  for(i=0, j=pPragma->iPragCName; i<pPragma->nPragCName; i++, j++){
    sqlite3_str_appendf(&acc, "%c\"%s\"", cSep, pragCName[j]);
    cSep = ',';
  }
  if( i==0 ){
    sqlite3_str_appendf(&acc, "(\"%s\"", pPragma->zName);
    i++;
  }
  j = 0;
  if( pPragma->mPragFlg & PragFlg_Result1 ){
    sqlite3_str_appendall(&acc, ",arg HIDDEN");
    j++;
  }
  if( pPragma->mPragFlg & (PragFlg_SchemaOpt|PragFlg_SchemaReq) ){
    sqlite3_str_appendall(&acc, ",schema HIDDEN");
    j++;
  }
  sqlite3_str_append(&acc, ")", 1);
  sqlite3StrAccumFinish(&acc);
  assert( strlen(zBuf) < sizeof(zBuf)-1 );
  rc = sqlite3_declare_vtab(db, zBuf);
  if( rc==SQLITE_OK ){
    pTab = (PragmaVtab*)sqlite3_malloc(sizeof(PragmaVtab));
    if( pTab==0 ){
      rc = SQLITE_NOMEM;
    }else{
      memset(pTab, 0, sizeof(PragmaVtab));
      pTab->pName = pPragma;
      pTab->db = db;
      pTab->iHidden = i;
      pTab->nHidden = j;
    }
  }else{
    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
  }

  *ppVtab = (sqlite3_vtab*)pTab;
  return rc;
}

/*
** Pragma virtual table module xDisconnect method.
*/
static int pragmaVtabDisconnect(sqlite3_vtab *pVtab){
  PragmaVtab *pTab = (PragmaVtab*)pVtab;
  sqlite3_free(pTab);
  return SQLITE_OK;
}

/* Figure out the best index to use to search a pragma virtual table.
**
** There are not really any index choices.  But we want to encourage the
** query planner to give == constraints on as many hidden parameters as
** possible, and especially on the first hidden parameter.  So return a
** high cost if hidden parameters are unconstrained.
*/
static int pragmaVtabBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
  PragmaVtab *pTab = (PragmaVtab*)tab;
  const struct sqlite3_index_constraint *pConstraint;
  int i, j;
  int seen[2];

  pIdxInfo->estimatedCost = (double)1;
  if( pTab->nHidden==0 ){ return SQLITE_OK; }
  pConstraint = pIdxInfo->aConstraint;
  seen[0] = 0;
  seen[1] = 0;
  for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
    if( pConstraint->iColumn < pTab->iHidden ) continue;
    if( pConstraint->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
    if( pConstraint->usable==0 ) return SQLITE_CONSTRAINT;
    j = pConstraint->iColumn - pTab->iHidden;
    assert( j < 2 );
    seen[j] = i+1;
  }
  if( seen[0]==0 ){
    pIdxInfo->estimatedCost = (double)2147483647;
    pIdxInfo->estimatedRows = 2147483647;
    return SQLITE_OK;
  }
  j = seen[0]-1;
  pIdxInfo->aConstraintUsage[j].argvIndex = 1;
  pIdxInfo->aConstraintUsage[j].omit = 1;
  pIdxInfo->estimatedCost = (double)20;
  pIdxInfo->estimatedRows = 20;
  if( seen[1] ){
    j = seen[1]-1;
    pIdxInfo->aConstraintUsage[j].argvIndex = 2;
    pIdxInfo->aConstraintUsage[j].omit = 1;
  }
  return SQLITE_OK;
}

/* Create a new cursor for the pragma virtual table */
static int pragmaVtabOpen(sqlite3_vtab *pVtab, sqlite3_vtab_cursor **ppCursor){
  PragmaVtabCursor *pCsr;
  pCsr = (PragmaVtabCursor*)sqlite3_malloc(sizeof(*pCsr));
  if( pCsr==0 ) return SQLITE_NOMEM;
  memset(pCsr, 0, sizeof(PragmaVtabCursor));
  pCsr->base.pVtab = pVtab;
  *ppCursor = &pCsr->base;
  return SQLITE_OK;
}

/* Clear all content from pragma virtual table cursor. */
static void pragmaVtabCursorClear(PragmaVtabCursor *pCsr){
  int i;
  sqlite3_finalize(pCsr->pPragma);
  pCsr->pPragma = 0;
  pCsr->iRowid = 0;
  for(i=0; i<ArraySize(pCsr->azArg); i++){
    sqlite3_free(pCsr->azArg[i]);
    pCsr->azArg[i] = 0;
  }
}

/* Close a pragma virtual table cursor */
static int pragmaVtabClose(sqlite3_vtab_cursor *cur){
  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)cur;
  pragmaVtabCursorClear(pCsr);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

/* Advance the pragma virtual table cursor to the next row */
static int pragmaVtabNext(sqlite3_vtab_cursor *pVtabCursor){
  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
  int rc = SQLITE_OK;

  /* Increment the xRowid value */
  pCsr->iRowid++;
  assert( pCsr->pPragma );
  if( SQLITE_ROW!=sqlite3_step(pCsr->pPragma) ){
    rc = sqlite3_finalize(pCsr->pPragma);
    pCsr->pPragma = 0;
    pragmaVtabCursorClear(pCsr);
  }
  return rc;
}

/*
** Pragma virtual table module xFilter method.
*/
static int pragmaVtabFilter(
  sqlite3_vtab_cursor *pVtabCursor,
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
  PragmaVtab *pTab = (PragmaVtab*)(pVtabCursor->pVtab);
  int rc;
  int i, j;
  StrAccum acc;
  char *zSql;

  UNUSED_PARAMETER(idxNum);
  UNUSED_PARAMETER(idxStr);
  pragmaVtabCursorClear(pCsr);
  j = (pTab->pName->mPragFlg & PragFlg_Result1)!=0 ? 0 : 1;
  for(i=0; i<argc; i++, j++){
    const char *zText = (const char*)sqlite3_value_text(argv[i]);
    assert( j<ArraySize(pCsr->azArg) );
    assert( pCsr->azArg[j]==0 );
    if( zText ){
      pCsr->azArg[j] = sqlite3_mprintf("%s", zText);
      if( pCsr->azArg[j]==0 ){
        return SQLITE_NOMEM;
      }
    }
  }
  sqlite3StrAccumInit(&acc, 0, 0, 0, pTab->db->aLimit[SQLITE_LIMIT_SQL_LENGTH]);
  sqlite3_str_appendall(&acc, "PRAGMA ");
  if( pCsr->azArg[1] ){
    sqlite3_str_appendf(&acc, "%Q.", pCsr->azArg[1]);
  }
  sqlite3_str_appendall(&acc, pTab->pName->zName);
  if( pCsr->azArg[0] ){
    sqlite3_str_appendf(&acc, "=%Q", pCsr->azArg[0]);
  }
  zSql = sqlite3StrAccumFinish(&acc);
  if( zSql==0 ) return SQLITE_NOMEM;
  rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pCsr->pPragma, 0);
  sqlite3_free(zSql);
  if( rc!=SQLITE_OK ){
    pTab->base.zErrMsg = sqlite3_mprintf("%s", sqlite3_errmsg(pTab->db));
    return rc;
  }
  return pragmaVtabNext(pVtabCursor);
}

/*
** Pragma virtual table module xEof method.
*/
static int pragmaVtabEof(sqlite3_vtab_cursor *pVtabCursor){
  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
  return (pCsr->pPragma==0);
}

/* The xColumn method simply returns the corresponding column from
** the PRAGMA.
*/
static int pragmaVtabColumn(
  sqlite3_vtab_cursor *pVtabCursor,
  sqlite3_context *ctx,
  int i
){
  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
  PragmaVtab *pTab = (PragmaVtab*)(pVtabCursor->pVtab);
  if( i<pTab->iHidden ){
    sqlite3_result_value(ctx, sqlite3_column_value(pCsr->pPragma, i));
  }else{
    sqlite3_result_text(ctx, pCsr->azArg[i-pTab->iHidden],-1,SQLITE_TRANSIENT);
  }
  return SQLITE_OK;
}

/*
** Pragma virtual table module xRowid method.
*/
static int pragmaVtabRowid(sqlite3_vtab_cursor *pVtabCursor, sqlite_int64 *p){
  PragmaVtabCursor *pCsr = (PragmaVtabCursor*)pVtabCursor;
  *p = pCsr->iRowid;
  return SQLITE_OK;
}

/* The pragma virtual table object */
static const sqlite3_module pragmaVtabModule = {
  0,                           /* iVersion */
  0,                           /* xCreate - create a table */
  pragmaVtabConnect,           /* xConnect - connect to an existing table */
  pragmaVtabBestIndex,         /* xBestIndex - Determine search strategy */
  pragmaVtabDisconnect,        /* xDisconnect - Disconnect from a table */
  0,                           /* xDestroy - Drop a table */
  pragmaVtabOpen,              /* xOpen - open a cursor */
  pragmaVtabClose,             /* xClose - close a cursor */
  pragmaVtabFilter,            /* xFilter - configure scan constraints */
  pragmaVtabNext,              /* xNext - advance a cursor */
  pragmaVtabEof,               /* xEof */
  pragmaVtabColumn,            /* xColumn - read data */
  pragmaVtabRowid,             /* xRowid - read data */
  0,                           /* xUpdate - write data */
  0,                           /* xBegin - begin transaction */
  0,                           /* xSync - sync transaction */
  0,                           /* xCommit - commit transaction */
  0,                           /* xRollback - rollback transaction */
  0,                           /* xFindFunction - function overloading */
  0,                           /* xRename - rename the table */
  0,                           /* xSavepoint */
  0,                           /* xRelease */
  0,                           /* xRollbackTo */
  0,                           /* xShadowName */
  0                            /* xIntegrity */
};

/*
** Check to see if zTabName is really the name of a pragma.  If it is,
** then register an eponymous virtual table for that pragma and return
** a pointer to the Module object for the new virtual table.
*/
SQLITE_PRIVATE Module *sqlite3PragmaVtabRegister(sqlite3 *db, const char *zName){
  const PragmaName *pName;
  assert( sqlite3_strnicmp(zName, "pragma_", 7)==0 );
  pName = pragmaLocate(zName+7);
  if( pName==0 ) return 0;
  if( (pName->mPragFlg & (PragFlg_Result0|PragFlg_Result1))==0 ) return 0;
  assert( sqlite3HashFind(&db->aModule, zName)==0 );
  return sqlite3VtabCreateModule(db, zName, &pragmaVtabModule, (void*)pName, 0);
}

#endif /* SQLITE_OMIT_VIRTUALTABLE */

#endif /* SQLITE_OMIT_PRAGMA */

/************** End of pragma.c **********************************************/
/************** Begin file prepare.c *****************************************/
/*
** 2005 May 25
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains the implementation of the sqlite3_prepare()
** interface, and routines that contribute to loading the database schema
** from disk.
*/
/* #include "sqliteInt.h" */

/*
** Fill the InitData structure with an error message that indicates
** that the database is corrupt.
*/
static void corruptSchema(

sqlite3.c  view on Meta::CPAN

  }
  return 0;
}

/*
** Attempt to read the database schema and initialize internal
** data structures for a single database file.  The index of the
** database file is given by iDb.  iDb==0 is used for the main
** database.  iDb==1 should never be used.  iDb>=2 is used for
** auxiliary databases.  Return one of the SQLITE_ error codes to
** indicate success or failure.
*/
SQLITE_PRIVATE int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg, u32 mFlags){
  int rc;
  int i;
#ifndef SQLITE_OMIT_DEPRECATED
  int size;
#endif
  Db *pDb;
  char const *azArg[6];
  int meta[5];
  InitData initData;
  const char *zSchemaTabName;
  int openedTransaction = 0;
  int mask = ((db->mDbFlags & DBFLAG_EncodingFixed) | ~DBFLAG_EncodingFixed);

  assert( (db->mDbFlags & DBFLAG_SchemaKnownOk)==0 );
  assert( iDb>=0 && iDb<db->nDb );
  assert( db->aDb[iDb].pSchema );
  assert( sqlite3_mutex_held(db->mutex) );
  assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );

  db->init.busy = 1;

  /* Construct the in-memory representation schema tables (sqlite_schema or
  ** sqlite_temp_schema) by invoking the parser directly.  The appropriate
  ** table name will be inserted automatically by the parser so we can just
  ** use the abbreviation "x" here.  The parser will also automatically tag
  ** the schema table as read-only. */
  azArg[0] = "table";
  azArg[1] = zSchemaTabName = SCHEMA_TABLE(iDb);
  azArg[2] = azArg[1];
  azArg[3] = "1";
  azArg[4] = "CREATE TABLE x(type text,name text,tbl_name text,"
                            "rootpage int,sql text)";
  azArg[5] = 0;
  initData.db = db;
  initData.iDb = iDb;
  initData.rc = SQLITE_OK;
  initData.pzErrMsg = pzErrMsg;
  initData.mInitFlags = mFlags;
  initData.nInitRow = 0;
  initData.mxPage = 0;
  sqlite3InitCallback(&initData, 5, (char **)azArg, 0);
  db->mDbFlags &= mask;
  if( initData.rc ){
    rc = initData.rc;
    goto error_out;
  }

  /* Create a cursor to hold the database open
  */
  pDb = &db->aDb[iDb];
  if( pDb->pBt==0 ){
    assert( iDb==1 );
    DbSetProperty(db, 1, DB_SchemaLoaded);
    rc = SQLITE_OK;
    goto error_out;
  }

  /* If there is not already a read-only (or read-write) transaction opened
  ** on the b-tree database, open one now. If a transaction is opened, it
  ** will be closed before this function returns.  */
  sqlite3BtreeEnter(pDb->pBt);
  if( sqlite3BtreeTxnState(pDb->pBt)==SQLITE_TXN_NONE ){
    rc = sqlite3BtreeBeginTrans(pDb->pBt, 0, 0);
    if( rc!=SQLITE_OK ){
      sqlite3SetString(pzErrMsg, db, sqlite3ErrStr(rc));
      goto initone_error_out;
    }
    openedTransaction = 1;
  }

  /* Get the database meta information.
  **
  ** Meta values are as follows:
  **    meta[0]   Schema cookie.  Changes with each schema change.
  **    meta[1]   File format of schema layer.
  **    meta[2]   Size of the page cache.
  **    meta[3]   Largest rootpage (auto/incr_vacuum mode)
  **    meta[4]   Db text encoding. 1:UTF-8 2:UTF-16LE 3:UTF-16BE
  **    meta[5]   User version
  **    meta[6]   Incremental vacuum mode
  **    meta[7]   unused
  **    meta[8]   unused
  **    meta[9]   unused
  **
  ** Note: The #defined SQLITE_UTF* symbols in sqliteInt.h correspond to
  ** the possible values of meta[4].
  */
  for(i=0; i<ArraySize(meta); i++){
    sqlite3BtreeGetMeta(pDb->pBt, i+1, (u32 *)&meta[i]);
  }
  if( (db->flags & SQLITE_ResetDatabase)!=0 ){
    memset(meta, 0, sizeof(meta));
  }
  pDb->pSchema->schema_cookie = meta[BTREE_SCHEMA_VERSION-1];

  /* If opening a non-empty database, check the text encoding. For the
  ** main database, set sqlite3.enc to the encoding of the main database.
  ** For an attached db, it is an error if the encoding is not the same
  ** as sqlite3.enc.
  */
  if( meta[BTREE_TEXT_ENCODING-1] ){  /* text encoding */
    if( iDb==0 && (db->mDbFlags & DBFLAG_EncodingFixed)==0 ){
      u8 encoding;
#ifndef SQLITE_OMIT_UTF16
      /* If opening the main database, set ENC(db). */
      encoding = (u8)meta[BTREE_TEXT_ENCODING-1] & 3;
      if( encoding==0 ) encoding = SQLITE_UTF8;
#else

sqlite3.c  view on Meta::CPAN

    **
    ** If the new record does not need to be inserted into the sorter,
    ** jump to the next iteration of the loop. If the pSort->labelOBLopt
    ** value is not zero, then it is a label of where to jump.  Otherwise,
    ** just bypass the row insert logic.  See the header comment on the
    ** sqlite3WhereOrderByLimitOptLabel() function for additional info.
    */
    int iCsr = pSort->iECursor;
    sqlite3VdbeAddOp2(v, OP_IfNotZero, iLimit, sqlite3VdbeCurrentAddr(v)+4);
    VdbeCoverage(v);
    sqlite3VdbeAddOp2(v, OP_Last, iCsr, 0);
    iSkip = sqlite3VdbeAddOp4Int(v, OP_IdxLE,
                                 iCsr, 0, regBase+nOBSat, nExpr-nOBSat);
    VdbeCoverage(v);
    sqlite3VdbeAddOp1(v, OP_Delete, iCsr);
  }
  if( regRecord==0 ){
    regRecord = makeSorterRecord(pParse, pSort, pSelect, regBase, nBase);
  }
  if( pSort->sortFlags & SORTFLAG_UseSorter ){
    op = OP_SorterInsert;
  }else{
    op = OP_IdxInsert;
  }
  sqlite3VdbeAddOp4Int(v, op, pSort->iECursor, regRecord,
                       regBase+nOBSat, nBase-nOBSat);
  if( iSkip ){
    sqlite3VdbeChangeP2(v, iSkip,
         pSort->labelOBLopt ? pSort->labelOBLopt : sqlite3VdbeCurrentAddr(v));
  }
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
  pSort->addrPushEnd = sqlite3VdbeCurrentAddr(v)-1;
#endif
}

/*
** Add code to implement the OFFSET
*/
static void codeOffset(
  Vdbe *v,          /* Generate code into this VM */
  int iOffset,      /* Register holding the offset counter */
  int iContinue     /* Jump here to skip the current record */
){
  if( iOffset>0 ){
    sqlite3VdbeAddOp3(v, OP_IfPos, iOffset, iContinue, 1); VdbeCoverage(v);
    VdbeComment((v, "OFFSET"));
  }
}

/*
** Add code that will check to make sure the array of registers starting at
** iMem form a distinct entry. This is used by both "SELECT DISTINCT ..." and
** distinct aggregates ("SELECT count(DISTINCT <expr>) ..."). Three strategies
** are available. Which is used depends on the value of parameter eTnctType,
** as follows:
**
**   WHERE_DISTINCT_UNORDERED/WHERE_DISTINCT_NOOP:
**     Build an ephemeral table that contains all entries seen before and
**     skip entries which have been seen before.
**
**     Parameter iTab is the cursor number of an ephemeral table that must
**     be opened before the VM code generated by this routine is executed.
**     The ephemeral cursor table is queried for a record identical to the
**     record formed by the current array of registers. If one is found,
**     jump to VM address addrRepeat. Otherwise, insert a new record into
**     the ephemeral cursor and proceed.
**
**     The returned value in this case is a copy of parameter iTab.
**
**   WHERE_DISTINCT_ORDERED:
**     In this case rows are being delivered sorted order. The ephemeral
**     table is not required. Instead, the current set of values
**     is compared against previous row. If they match, the new row
**     is not distinct and control jumps to VM address addrRepeat. Otherwise,
**     the VM program proceeds with processing the new row.
**
**     The returned value in this case is the register number of the first
**     in an array of registers used to store the previous result row so that
**     it can be compared to the next. The caller must ensure that this
**     register is initialized to NULL.  (The fixDistinctOpenEph() routine
**     will take care of this initialization.)
**
**   WHERE_DISTINCT_UNIQUE:
**     In this case it has already been determined that the rows are distinct.
**     No special action is required. The return value is zero.
**
** Parameter pEList is the list of expressions used to generated the
** contents of each row. It is used by this routine to determine (a)
** how many elements there are in the array of registers and (b) the
** collation sequences that should be used for the comparisons if
** eTnctType is WHERE_DISTINCT_ORDERED.
*/
static int codeDistinct(
  Parse *pParse,     /* Parsing and code generating context */
  int eTnctType,     /* WHERE_DISTINCT_* value */
  int iTab,          /* A sorting index used to test for distinctness */
  int addrRepeat,    /* Jump to here if not distinct */
  ExprList *pEList,  /* Expression for each element */
  int regElem        /* First element */
){
  int iRet = 0;
  int nResultCol = pEList->nExpr;
  Vdbe *v = pParse->pVdbe;

  switch( eTnctType ){
    case WHERE_DISTINCT_ORDERED: {
      int i;
      int iJump;              /* Jump destination */
      int regPrev;            /* Previous row content */

      /* Allocate space for the previous row */
      iRet = regPrev = pParse->nMem+1;
      pParse->nMem += nResultCol;

      iJump = sqlite3VdbeCurrentAddr(v) + nResultCol;
      for(i=0; i<nResultCol; i++){
        CollSeq *pColl = sqlite3ExprCollSeq(pParse, pEList->a[i].pExpr);
        if( i<nResultCol-1 ){
          sqlite3VdbeAddOp3(v, OP_Ne, regElem+i, iJump, regPrev+i);
          VdbeCoverage(v);
        }else{
          sqlite3VdbeAddOp3(v, OP_Eq, regElem+i, addrRepeat, regPrev+i);
          VdbeCoverage(v);
         }
        sqlite3VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ);
        sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);

sqlite3.c  view on Meta::CPAN

**     No adjustments necessary.  This function is a no-op.
**
** WHERE_DISTINCT_UNIQUE:
**
**     The ephemeral table is not needed.  So change the
**     OP_OpenEphemeral opcode into an OP_Noop.
**
** WHERE_DISTINCT_ORDERED:
**
**     The ephemeral table is not needed.  But we do need register
**     iVal to be initialized to NULL.  So change the OP_OpenEphemeral
**     into an OP_Null on the iVal register.
*/
static void fixDistinctOpenEph(
  Parse *pParse,     /* Parsing and code generating context */
  int eTnctType,     /* WHERE_DISTINCT_* value */
  int iVal,          /* Value returned by codeDistinct() */
  int iOpenEphAddr   /* Address of OP_OpenEphemeral instruction for iTab */
){
  if( pParse->nErr==0
   && (eTnctType==WHERE_DISTINCT_UNIQUE || eTnctType==WHERE_DISTINCT_ORDERED)
  ){
    Vdbe *v = pParse->pVdbe;
    sqlite3VdbeChangeToNoop(v, iOpenEphAddr);
    if( sqlite3VdbeGetOp(v, iOpenEphAddr+1)->opcode==OP_Explain ){
      sqlite3VdbeChangeToNoop(v, iOpenEphAddr+1);
    }
    if( eTnctType==WHERE_DISTINCT_ORDERED ){
      /* Change the OP_OpenEphemeral to an OP_Null that sets the MEM_Cleared
      ** bit on the first register of the previous value.  This will cause the
      ** OP_Ne added in codeDistinct() to always fail on the first iteration of
      ** the loop even if the first row is all NULLs.  */
      VdbeOp *pOp = sqlite3VdbeGetOp(v, iOpenEphAddr);
      pOp->opcode = OP_Null;
      pOp->p1 = 1;
      pOp->p2 = iVal;
    }
  }
}

#ifdef SQLITE_ENABLE_SORTER_REFERENCES
/*
** This function is called as part of inner-loop generation for a SELECT
** statement with an ORDER BY that is not optimized by an index. It
** determines the expressions, if any, that the sorter-reference
** optimization should be used for. The sorter-reference optimization
** is used for SELECT queries like:
**
**   SELECT a, bigblob FROM t1 ORDER BY a LIMIT 10
**
** If the optimization is used for expression "bigblob", then instead of
** storing values read from that column in the sorter records, the PK of
** the row from table t1 is stored instead. Then, as records are extracted from
** the sorter to return to the user, the required value of bigblob is
** retrieved directly from table t1. If the values are very large, this
** can be more efficient than storing them directly in the sorter records.
**
** The ExprList_item.fg.bSorterRef flag is set for each expression in pEList
** for which the sorter-reference optimization should be enabled.
** Additionally, the pSort->aDefer[] array is populated with entries
** for all cursors required to evaluate all selected expressions. Finally.
** output variable (*ppExtra) is set to an expression list containing
** expressions for all extra PK values that should be stored in the
** sorter records.
*/
static void selectExprDefer(
  Parse *pParse,                  /* Leave any error here */
  SortCtx *pSort,                 /* Sorter context */
  ExprList *pEList,               /* Expressions destined for sorter */
  ExprList **ppExtra              /* Expressions to append to sorter record */
){
  int i;
  int nDefer = 0;
  ExprList *pExtra = 0;
  for(i=0; i<pEList->nExpr; i++){
    struct ExprList_item *pItem = &pEList->a[i];
    if( pItem->u.x.iOrderByCol==0 ){
      Expr *pExpr = pItem->pExpr;
      Table *pTab;
      if( pExpr->op==TK_COLUMN
       && pExpr->iColumn>=0
       && ALWAYS( ExprUseYTab(pExpr) )
       && (pTab = pExpr->y.pTab)!=0
       && IsOrdinaryTable(pTab)
       && (pTab->aCol[pExpr->iColumn].colFlags & COLFLAG_SORTERREF)!=0
      ){
        int j;
        for(j=0; j<nDefer; j++){
          if( pSort->aDefer[j].iCsr==pExpr->iTable ) break;
        }
        if( j==nDefer ){
          if( nDefer==ArraySize(pSort->aDefer) ){
            continue;
          }else{
            int nKey = 1;
            int k;
            Index *pPk = 0;
            if( !HasRowid(pTab) ){
              pPk = sqlite3PrimaryKeyIndex(pTab);
              nKey = pPk->nKeyCol;
            }
            for(k=0; k<nKey; k++){
              Expr *pNew = sqlite3PExpr(pParse, TK_COLUMN, 0, 0);
              if( pNew ){
                pNew->iTable = pExpr->iTable;
                assert( ExprUseYTab(pNew) );
                pNew->y.pTab = pExpr->y.pTab;
                pNew->iColumn = pPk ? pPk->aiColumn[k] : -1;
                pExtra = sqlite3ExprListAppend(pParse, pExtra, pNew);
              }
            }
            pSort->aDefer[nDefer].pTab = pExpr->y.pTab;
            pSort->aDefer[nDefer].iCsr = pExpr->iTable;
            pSort->aDefer[nDefer].nKey = nKey;
            nDefer++;
          }
        }
        pItem->fg.bSorterRef = 1;
      }
    }
  }

sqlite3.c  view on Meta::CPAN

  */
  if( hasDistinct ){
    int eType = pDistinct->eTnctType;
    int iTab = pDistinct->tabTnct;
    assert( nResultCol==p->pEList->nExpr );
    iTab = codeDistinct(pParse, eType, iTab, iContinue, p->pEList, regResult);
    fixDistinctOpenEph(pParse, eType, iTab, pDistinct->addrTnct);
    if( pSort==0 ){
      codeOffset(v, p->iOffset, iContinue);
    }
  }

  switch( eDest ){
    /* In this mode, write each query result to the key of the temporary
    ** table iParm.
    */
#ifndef SQLITE_OMIT_COMPOUND_SELECT
    case SRT_Union: {
      int r1;
      r1 = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1);
      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, nResultCol);
      sqlite3ReleaseTempReg(pParse, r1);
      break;
    }

    /* Construct a record from the query result, but instead of
    ** saving that record, use it as a key to delete elements from
    ** the temporary table iParm.
    */
    case SRT_Except: {
      sqlite3VdbeAddOp3(v, OP_IdxDelete, iParm, regResult, nResultCol);
      break;
    }
#endif /* SQLITE_OMIT_COMPOUND_SELECT */

    /* Store the result as data using a unique key.
    */
    case SRT_Fifo:
    case SRT_DistFifo:
    case SRT_Table:
    case SRT_EphemTab: {
      int r1 = sqlite3GetTempRange(pParse, nPrefixReg+1);
      testcase( eDest==SRT_Table );
      testcase( eDest==SRT_EphemTab );
      testcase( eDest==SRT_Fifo );
      testcase( eDest==SRT_DistFifo );
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r1+nPrefixReg);
#if !defined(SQLITE_ENABLE_NULL_TRIM) && defined(SQLITE_DEBUG)
      /* A destination of SRT_Table and a non-zero iSDParm2 parameter means
      ** that this is an "UPDATE ... FROM" on a virtual table or view. In this
      ** case set the p5 parameter of the OP_MakeRecord to OPFLAG_NOCHNG_MAGIC.
      ** This does not affect operation in any way - it just allows MakeRecord
      ** to process OPFLAG_NOCHANGE values without an assert() failing. */
      if( eDest==SRT_Table && pDest->iSDParm2 ){
        sqlite3VdbeChangeP5(v, OPFLAG_NOCHNG_MAGIC);
      }
#endif
#ifndef SQLITE_OMIT_CTE
      if( eDest==SRT_DistFifo ){
        /* If the destination is DistFifo, then cursor (iParm+1) is open
        ** on an ephemeral index. If the current row is already present
        ** in the index, do not write it to the output. If not, add the
        ** current row to the index and proceed with writing it to the
        ** output table as well.  */
        int addr = sqlite3VdbeCurrentAddr(v) + 4;
        sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, addr, r1, 0);
        VdbeCoverage(v);
        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm+1, r1,regResult,nResultCol);
        assert( pSort==0 );
      }
#endif
      if( pSort ){
        assert( regResult==regOrig );
        pushOntoSorter(pParse, pSort, p, r1+nPrefixReg, regOrig, 1, nPrefixReg);
      }else{
        int r2 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp2(v, OP_NewRowid, iParm, r2);
        sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, r2);
        sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
        sqlite3ReleaseTempReg(pParse, r2);
      }
      sqlite3ReleaseTempRange(pParse, r1, nPrefixReg+1);
      break;
    }

    case SRT_Upfrom: {
      if( pSort ){
        pushOntoSorter(
            pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg);
      }else{
        int i2 = pDest->iSDParm2;
        int r1 = sqlite3GetTempReg(pParse);

        /* If the UPDATE FROM join is an aggregate that matches no rows, it
        ** might still be trying to return one row, because that is what
        ** aggregates do.  Don't record that empty row in the output table. */
        sqlite3VdbeAddOp2(v, OP_IsNull, regResult, iBreak); VdbeCoverage(v);

        sqlite3VdbeAddOp3(v, OP_MakeRecord,
                          regResult+(i2<0), nResultCol-(i2<0), r1);
        if( i2<0 ){
          sqlite3VdbeAddOp3(v, OP_Insert, iParm, r1, regResult);
        }else{
          sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, i2);
        }
      }
      break;
    }

#ifndef SQLITE_OMIT_SUBQUERY
    /* If we are creating a set for an "expr IN (SELECT ...)" construct,
    ** then there should be a single item on the stack.  Write this
    ** item into the set table with bogus data.
    */
    case SRT_Set: {
      if( pSort ){
        /* At first glance you would think we could optimize out the
        ** ORDER BY in this case since the order of entries in the set
        ** does not matter.  But there might be a LIMIT clause, in which
        ** case the order does matter */

sqlite3.c  view on Meta::CPAN

      }else{
        int r1 = sqlite3GetTempReg(pParse);
        assert( sqlite3Strlen30(pDest->zAffSdst)==nResultCol );
        sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, nResultCol,
            r1, pDest->zAffSdst, nResultCol);
        sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, nResultCol);
        if( pDest->iSDParm2 ){
          sqlite3VdbeAddOp4Int(v, OP_FilterAdd, pDest->iSDParm2, 0,
                               regResult, nResultCol);
          ExplainQueryPlan((pParse, 0, "CREATE BLOOM FILTER"));
        }
        sqlite3ReleaseTempReg(pParse, r1);
      }
      break;
    }


    /* If any row exist in the result set, record that fact and abort.
    */
    case SRT_Exists: {
      sqlite3VdbeAddOp2(v, OP_Integer, 1, iParm);
      /* The LIMIT clause will terminate the loop for us */
      break;
    }

    /* If this is a scalar select that is part of an expression, then
    ** store the results in the appropriate memory cell or array of
    ** memory cells and break out of the scan loop.
    */
    case SRT_Mem: {
      if( pSort ){
        assert( nResultCol<=pDest->nSdst );
        pushOntoSorter(
            pParse, pSort, p, regResult, regOrig, nResultCol, nPrefixReg);
      }else{
        assert( nResultCol==pDest->nSdst );
        assert( regResult==iParm );
        /* The LIMIT clause will jump out of the loop for us */
      }
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */

    case SRT_Coroutine:       /* Send data to a co-routine */
    case SRT_Output: {        /* Return the results */
      testcase( eDest==SRT_Coroutine );
      testcase( eDest==SRT_Output );
      if( pSort ){
        pushOntoSorter(pParse, pSort, p, regResult, regOrig, nResultCol,
                       nPrefixReg);
      }else if( eDest==SRT_Coroutine ){
        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
      }else{
        sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nResultCol);
      }
      break;
    }

#ifndef SQLITE_OMIT_CTE
    /* Write the results into a priority queue that is order according to
    ** pDest->pOrderBy (in pSO).  pDest->iSDParm (in iParm) is the cursor for an
    ** index with pSO->nExpr+2 columns.  Build a key using pSO for the first
    ** pSO->nExpr columns, then make sure all keys are unique by adding a
    ** final OP_Sequence column.  The last column is the record as a blob.
    */
    case SRT_DistQueue:
    case SRT_Queue: {
      int nKey;
      int r1, r2, r3;
      int addrTest = 0;
      ExprList *pSO;
      pSO = pDest->pOrderBy;
      assert( pSO );
      nKey = pSO->nExpr;
      r1 = sqlite3GetTempReg(pParse);
      r2 = sqlite3GetTempRange(pParse, nKey+2);
      r3 = r2+nKey+1;
      if( eDest==SRT_DistQueue ){
        /* If the destination is DistQueue, then cursor (iParm+1) is open
        ** on a second ephemeral index that holds all values every previously
        ** added to the queue. */
        addrTest = sqlite3VdbeAddOp4Int(v, OP_Found, iParm+1, 0,
                                        regResult, nResultCol);
        VdbeCoverage(v);
      }
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nResultCol, r3);
      if( eDest==SRT_DistQueue ){
        sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm+1, r3);
        sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
      }
      for(i=0; i<nKey; i++){
        sqlite3VdbeAddOp2(v, OP_SCopy,
                          regResult + pSO->a[i].u.x.iOrderByCol - 1,
                          r2+i);
      }
      sqlite3VdbeAddOp2(v, OP_Sequence, iParm, r2+nKey);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, r2, nKey+2, r1);
      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, r2, nKey+2);
      if( addrTest ) sqlite3VdbeJumpHere(v, addrTest);
      sqlite3ReleaseTempReg(pParse, r1);
      sqlite3ReleaseTempRange(pParse, r2, nKey+2);
      break;
    }
#endif /* SQLITE_OMIT_CTE */



#if !defined(SQLITE_OMIT_TRIGGER)
    /* Discard the results.  This is used for SELECT statements inside
    ** the body of a TRIGGER.  The purpose of such selects is to call
    ** user-defined functions that have side effects.  We do not care
    ** about the actual results of the select.
    */
    default: {
      assert( eDest==SRT_Discard );
      break;
    }
#endif
  }

  /* Jump to the end of the loop if the LIMIT is reached.  Except, if
  ** there is a sorter, in which case the sorter has already limited
  ** the output for us.
  */
  if( pSort==0 && p->iLimit ){
    sqlite3VdbeAddOp2(v, OP_DecrJumpZero, p->iLimit, iBreak); VdbeCoverage(v);
  }
}

/*
** Allocate a KeyInfo object sufficient for an index of N key columns and
** X extra columns.
*/
SQLITE_PRIVATE KeyInfo *sqlite3KeyInfoAlloc(sqlite3 *db, int N, int X){
  int nExtra = (N+X)*(sizeof(CollSeq*)+1);
  KeyInfo *p;
  assert( X>=0 );
  if( NEVER(N+X>0xffff) ) return (KeyInfo*)sqlite3OomFault(db);
  p = sqlite3DbMallocRawNN(db, SZ_KEYINFO(0) + nExtra);

sqlite3.c  view on Meta::CPAN

  return z;
}

#ifndef SQLITE_OMIT_EXPLAIN
/*
** Unless an "EXPLAIN QUERY PLAN" command is being processed, this function
** is a no-op. Otherwise, it adds a single row of output to the EQP result,
** where the caption is of the form:
**
**   "USE TEMP B-TREE FOR xxx"
**
** where xxx is one of "DISTINCT", "ORDER BY" or "GROUP BY". Exactly which
** is determined by the zUsage argument.
*/
static void explainTempTable(Parse *pParse, const char *zUsage){
  ExplainQueryPlan((pParse, 0, "USE TEMP B-TREE FOR %s", zUsage));
}

/*
** Assign expression b to lvalue a. A second, no-op, version of this macro
** is provided when SQLITE_OMIT_EXPLAIN is defined. This allows the code
** in sqlite3Select() to assign values to structure member variables that
** only exist if SQLITE_OMIT_EXPLAIN is not defined without polluting the
** code with #ifndef directives.
*/
# define explainSetInteger(a, b) a = b

#else
/* No-op versions of the explainXXX() functions and macros. */
# define explainTempTable(y,z)
# define explainSetInteger(y,z)
#endif


/*
** If the inner loop was generated using a non-null pOrderBy argument,
** then the results were placed in a sorter.  After the loop is terminated
** we need to run the sorter and output the results.  The following
** routine generates the code needed to do that.
*/
static void generateSortTail(
  Parse *pParse,    /* Parsing context */
  Select *p,        /* The SELECT statement */
  SortCtx *pSort,   /* Information on the ORDER BY clause */
  int nColumn,      /* Number of columns of data */
  SelectDest *pDest /* Write the sorted results here */
){
  Vdbe *v = pParse->pVdbe;                     /* The prepared statement */
  int addrBreak = pSort->labelDone;            /* Jump here to exit loop */
  int addrContinue = sqlite3VdbeMakeLabel(pParse);/* Jump here for next cycle */
  int addr;                       /* Top of output loop. Jump for Next. */
  int addrOnce = 0;
  int iTab;
  ExprList *pOrderBy = pSort->pOrderBy;
  int eDest = pDest->eDest;
  int iParm = pDest->iSDParm;
  int regRow;
  int regRowid;
  int iCol;
  int nKey;                       /* Number of key columns in sorter record */
  int iSortTab;                   /* Sorter cursor to read from */
  int i;
  int bSeq;                       /* True if sorter record includes seq. no. */
  int nRefKey = 0;
  struct ExprList_item *aOutEx = p->pEList->a;
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
  int addrExplain;                /* Address of OP_Explain instruction */
#endif

  nKey = pOrderBy->nExpr - pSort->nOBSat;
  if( pSort->nOBSat==0 || nKey==1 ){
    ExplainQueryPlan2(addrExplain, (pParse, 0,
      "USE TEMP B-TREE FOR %sORDER BY", pSort->nOBSat?"LAST TERM OF ":""
    ));
  }else{
    ExplainQueryPlan2(addrExplain, (pParse, 0,
      "USE TEMP B-TREE FOR LAST %d TERMS OF ORDER BY", nKey
    ));
  }
  sqlite3VdbeScanStatusRange(v, addrExplain,pSort->addrPush,pSort->addrPushEnd);
  sqlite3VdbeScanStatusCounters(v, addrExplain, addrExplain, pSort->addrPush);


  assert( addrBreak<0 );
  if( pSort->labelBkOut ){
    sqlite3VdbeAddOp2(v, OP_Gosub, pSort->regReturn, pSort->labelBkOut);
    sqlite3VdbeGoto(v, addrBreak);
    sqlite3VdbeResolveLabel(v, pSort->labelBkOut);
  }

#ifdef SQLITE_ENABLE_SORTER_REFERENCES
  /* Open any cursors needed for sorter-reference expressions */
  for(i=0; i<pSort->nDefer; i++){
    Table *pTab = pSort->aDefer[i].pTab;
    int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
    sqlite3OpenTable(pParse, pSort->aDefer[i].iCsr, iDb, pTab, OP_OpenRead);
    nRefKey = MAX(nRefKey, pSort->aDefer[i].nKey);
  }
#endif

  iTab = pSort->iECursor;
  if( eDest==SRT_Output || eDest==SRT_Coroutine || eDest==SRT_Mem ){
    if( eDest==SRT_Mem && p->iOffset ){
      sqlite3VdbeAddOp2(v, OP_Null, 0, pDest->iSdst);
    }
    regRowid = 0;
    regRow = pDest->iSdst;
  }else{
    regRowid = sqlite3GetTempReg(pParse);
    if( eDest==SRT_EphemTab || eDest==SRT_Table ){
      regRow = sqlite3GetTempReg(pParse);
      nColumn = 0;
    }else{
      regRow = sqlite3GetTempRange(pParse, nColumn);
    }
  }
  if( pSort->sortFlags & SORTFLAG_UseSorter ){
    int regSortOut = ++pParse->nMem;
    iSortTab = pParse->nTab++;
    if( pSort->labelBkOut ){
      addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
    }
    sqlite3VdbeAddOp3(v, OP_OpenPseudo, iSortTab, regSortOut,
        nKey+1+nColumn+nRefKey);
    if( addrOnce ) sqlite3VdbeJumpHere(v, addrOnce);
    addr = 1 + sqlite3VdbeAddOp2(v, OP_SorterSort, iTab, addrBreak);
    VdbeCoverage(v);
    assert( p->iLimit==0 && p->iOffset==0 );
    sqlite3VdbeAddOp3(v, OP_SorterData, iTab, regSortOut, iSortTab);
    bSeq = 0;
  }else{
    addr = 1 + sqlite3VdbeAddOp2(v, OP_Sort, iTab, addrBreak); VdbeCoverage(v);
    codeOffset(v, p->iOffset, addrContinue);
    iSortTab = iTab;
    bSeq = 1;
    if( p->iOffset>0 ){
      sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
    }
  }
  for(i=0, iCol=nKey+bSeq-1; i<nColumn; i++){
#ifdef SQLITE_ENABLE_SORTER_REFERENCES
    if( aOutEx[i].fg.bSorterRef ) continue;
#endif
    if( aOutEx[i].u.x.iOrderByCol==0 ) iCol++;
  }
#ifdef SQLITE_ENABLE_SORTER_REFERENCES
  if( pSort->nDefer ){
    int iKey = iCol+1;
    int regKey = sqlite3GetTempRange(pParse, nRefKey);

    for(i=0; i<pSort->nDefer; i++){
      int iCsr = pSort->aDefer[i].iCsr;

sqlite3.c  view on Meta::CPAN

** inserted into the Queue table.  The iDistinct table keeps a copy of all rows
** that have ever been inserted into Queue and causes duplicates to be
** discarded.  If the operator is UNION ALL, then duplicates are allowed.
**
** If the query has an ORDER BY, then entries in the Queue table are kept in
** ORDER BY order and the first entry is extracted for each cycle.  Without
** an ORDER BY, the Queue table is just a FIFO.
**
** If a LIMIT clause is provided, then the iteration stops after LIMIT rows
** have been output to pDest.  A LIMIT of zero means to output no rows and a
** negative LIMIT means to output all rows.  If there is also an OFFSET clause
** with a positive value, then the first OFFSET outputs are discarded rather
** than being sent to pDest.  The LIMIT count does not begin until after OFFSET
** rows have been skipped.
*/
static void generateWithRecursiveQuery(
  Parse *pParse,        /* Parsing context */
  Select *p,            /* The recursive SELECT to be coded */
  SelectDest *pDest     /* What to do with query results */
){
  SrcList *pSrc = p->pSrc;      /* The FROM clause of the recursive query */
  int nCol = p->pEList->nExpr;  /* Number of columns in the recursive table */
  Vdbe *v = pParse->pVdbe;      /* The prepared statement under construction */
  Select *pSetup;               /* The setup query */
  Select *pFirstRec;            /* Left-most recursive term */
  int addrTop;                  /* Top of the loop */
  int addrCont, addrBreak;      /* CONTINUE and BREAK addresses */
  int iCurrent = 0;             /* The Current table */
  int regCurrent;               /* Register holding Current table */
  int iQueue;                   /* The Queue table */
  int iDistinct = 0;            /* To ensure unique results if UNION */
  int eDest = SRT_Fifo;         /* How to write to Queue */
  SelectDest destQueue;         /* SelectDest targeting the Queue table */
  int i;                        /* Loop counter */
  int rc;                       /* Result code */
  ExprList *pOrderBy;           /* The ORDER BY clause */
  Expr *pLimit;                 /* Saved LIMIT and OFFSET */
  int regLimit, regOffset;      /* Registers used by LIMIT and OFFSET */

#ifndef SQLITE_OMIT_WINDOWFUNC
  if( p->pWin ){
    sqlite3ErrorMsg(pParse, "cannot use window functions in recursive queries");
    return;
  }
#endif

  /* Obtain authorization to do a recursive query */
  if( sqlite3AuthCheck(pParse, SQLITE_RECURSIVE, 0, 0, 0) ) return;

  /* Process the LIMIT and OFFSET clauses, if they exist */
  addrBreak = sqlite3VdbeMakeLabel(pParse);
  p->nSelectRow = 320;  /* 4 billion rows */
  computeLimitRegisters(pParse, p, addrBreak);
  pLimit = p->pLimit;
  regLimit = p->iLimit;
  regOffset = p->iOffset;
  p->pLimit = 0;
  p->iLimit = p->iOffset = 0;
  pOrderBy = p->pOrderBy;

  /* Locate the cursor number of the Current table */
  for(i=0; ALWAYS(i<pSrc->nSrc); i++){
    if( pSrc->a[i].fg.isRecursive ){
      iCurrent = pSrc->a[i].iCursor;
      break;
    }
  }

  /* Allocate cursors numbers for Queue and Distinct.  The cursor number for
  ** the Distinct table must be exactly one greater than Queue in order
  ** for the SRT_DistFifo and SRT_DistQueue destinations to work. */
  iQueue = pParse->nTab++;
  if( p->op==TK_UNION ){
    eDest = pOrderBy ? SRT_DistQueue : SRT_DistFifo;
    iDistinct = pParse->nTab++;
  }else{
    eDest = pOrderBy ? SRT_Queue : SRT_Fifo;
  }
  sqlite3SelectDestInit(&destQueue, eDest, iQueue);

  /* Allocate cursors for Current, Queue, and Distinct. */
  regCurrent = ++pParse->nMem;
  sqlite3VdbeAddOp3(v, OP_OpenPseudo, iCurrent, regCurrent, nCol);
  if( pOrderBy ){
    KeyInfo *pKeyInfo = multiSelectOrderByKeyInfo(pParse, p, 1);
    sqlite3VdbeAddOp4(v, OP_OpenEphemeral, iQueue, pOrderBy->nExpr+2, 0,
                      (char*)pKeyInfo, P4_KEYINFO);
    destQueue.pOrderBy = pOrderBy;
  }else{
    sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iQueue, nCol);
  }
  VdbeComment((v, "Queue table"));
  if( iDistinct ){
    p->addrOpenEphm[0] = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iDistinct, 0);
    p->selFlags |= SF_UsesEphemeral;
  }

  /* Detach the ORDER BY clause from the compound SELECT */
  p->pOrderBy = 0;

  /* Figure out how many elements of the compound SELECT are part of the
  ** recursive query.  Make sure no recursive elements use aggregate
  ** functions.  Mark the recursive elements as UNION ALL even if they
  ** are really UNION because the distinctness will be enforced by the
  ** iDistinct table.  pFirstRec is left pointing to the left-most
  ** recursive term of the CTE.
  */
  for(pFirstRec=p; ALWAYS(pFirstRec!=0); pFirstRec=pFirstRec->pPrior){
    if( pFirstRec->selFlags & SF_Aggregate ){
      sqlite3ErrorMsg(pParse, "recursive aggregate queries not supported");
      goto end_of_recursive_query;
    }
    pFirstRec->op = TK_ALL;
    if( (pFirstRec->pPrior->selFlags & SF_Recursive)==0 ) break;
  }

  /* Store the results of the setup-query in Queue. */
  pSetup = pFirstRec->pPrior;
  pSetup->pNext = 0;
  ExplainQueryPlan((pParse, 1, "SETUP"));
  rc = sqlite3Select(pParse, pSetup, &destQueue);
  pSetup->pNext = p;
  if( rc ) goto end_of_recursive_query;

  /* Find the next row in the Queue and output that row */
  addrTop = sqlite3VdbeAddOp2(v, OP_Rewind, iQueue, addrBreak); VdbeCoverage(v);

  /* Transfer the next row in Queue over to Current */
  sqlite3VdbeAddOp1(v, OP_NullRow, iCurrent); /* To reset column cache */
  if( pOrderBy ){
    sqlite3VdbeAddOp3(v, OP_Column, iQueue, pOrderBy->nExpr+1, regCurrent);
  }else{
    sqlite3VdbeAddOp2(v, OP_RowData, iQueue, regCurrent);
  }
  sqlite3VdbeAddOp1(v, OP_Delete, iQueue);

  /* Output the single row in Current */
  addrCont = sqlite3VdbeMakeLabel(pParse);
  codeOffset(v, regOffset, addrCont);
  selectInnerLoop(pParse, p, iCurrent,
      0, 0, pDest, addrCont, addrBreak);

sqlite3.c  view on Meta::CPAN

  /* Generate code to handle the case of A<B
  */
  VdbeNoopComment((v, "A-lt-B subroutine"));
  addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
  sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA); VdbeCoverage(v);
  sqlite3VdbeGoto(v, labelCmpr);

  /* Generate code to handle the case of A==B
  */
  if( op==TK_ALL ){
    addrAeqB = addrAltB;
  }else if( op==TK_INTERSECT ){
    addrAeqB = addrAltB;
    addrAltB++;
  }else{
    VdbeNoopComment((v, "A-eq-B subroutine"));
    addrAeqB =
    sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA); VdbeCoverage(v);
    sqlite3VdbeGoto(v, labelCmpr);
  }

  /* Generate code to handle the case of A>B
  */
  VdbeNoopComment((v, "A-gt-B subroutine"));
  addrAgtB = sqlite3VdbeCurrentAddr(v);
  if( op==TK_ALL || op==TK_UNION ){
    sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
  }
  sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB); VdbeCoverage(v);
  sqlite3VdbeGoto(v, labelCmpr);

  /* This code runs once to initialize everything.
  */
  sqlite3VdbeJumpHere(v, addr1);
  sqlite3VdbeAddOp2(v, OP_Yield, regAddrA, addrEofA_noB); VdbeCoverage(v);
  sqlite3VdbeAddOp2(v, OP_Yield, regAddrB, addrEofB); VdbeCoverage(v);

  /* Implement the main merge loop
  */
  sqlite3VdbeResolveLabel(v, labelCmpr);
  sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);
  sqlite3VdbeAddOp4(v, OP_Compare, destA.iSdst, destB.iSdst, nOrderBy,
                         (char*)pKeyMerge, P4_KEYINFO);
  sqlite3VdbeChangeP5(v, OPFLAG_PERMUTE);
  sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB); VdbeCoverage(v);

  /* Jump to the this point in order to terminate the query.
  */
  sqlite3VdbeResolveLabel(v, labelEnd);

  /* Make arrangements to free the 2nd and subsequent arms of the compound
  ** after the parse has finished */
  if( pSplit->pPrior ){
    sqlite3ParserAddCleanup(pParse, sqlite3SelectDeleteGeneric, pSplit->pPrior);
  }
  pSplit->pPrior = pPrior;
  pPrior->pNext = pSplit;
  sqlite3ExprListDelete(db, pPrior->pOrderBy);
  pPrior->pOrderBy = 0;

  /*** TBD:  Insert subroutine calls to close cursors on incomplete
  **** subqueries ****/
  ExplainQueryPlanPop(pParse);
  return pParse->nErr!=0;
}
#endif

#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)

/* An instance of the SubstContext object describes an substitution edit
** to be performed on a parse tree.
**
** All references to columns in table iTable are to be replaced by corresponding
** expressions in pEList.
**
** ## About "isOuterJoin":
**
** The isOuterJoin column indicates that the replacement will occur into a
** position in the parent that is NULL-able due to an OUTER JOIN.  Either the
** target slot in the parent is the right operand of a LEFT JOIN, or one of
** the left operands of a RIGHT JOIN.  In either case, we need to potentially
** bypass the substituted expression with OP_IfNullRow.
**
** Suppose the original expression is an integer constant. Even though the table
** has the nullRow flag set, because the expression is an integer constant,
** it will not be NULLed out.  So instead, we insert an OP_IfNullRow opcode
** that checks to see if the nullRow flag is set on the table.  If the nullRow
** flag is set, then the value in the register is set to NULL and the original
** expression is bypassed.  If the nullRow flag is not set, then the original
** expression runs to populate the register.
**
** Example where this is needed:
**
**      CREATE TABLE t1(a INTEGER PRIMARY KEY, b INT);
**      CREATE TABLE t2(x INT UNIQUE);
**
**      SELECT a,b,m,x FROM t1 LEFT JOIN (SELECT 59 AS m,x FROM t2) ON b=x;
**
** When the subquery on the right side of the LEFT JOIN is flattened, we
** have to add OP_IfNullRow in front of the OP_Integer that implements the
** "m" value of the subquery so that a NULL will be loaded instead of 59
** when processing a non-matched row of the left.
*/
typedef struct SubstContext {
  Parse *pParse;            /* The parsing context */
  int iTable;               /* Replace references to this table */
  int iNewTable;            /* New table number */
  int isOuterJoin;          /* Add TK_IF_NULL_ROW opcodes on each replacement */
  int nSelDepth;            /* Depth of sub-query recursion.  Top==1 */
  ExprList *pEList;         /* Replacement expressions */
  ExprList *pCList;         /* Collation sequences for replacement expr */
} SubstContext;

/* Forward Declarations */
static void substExprList(SubstContext*, ExprList*);
static void substSelect(SubstContext*, Select*, int);

/*
** Scan through the expression pExpr.  Replace every reference to
** a column in table number iTable with a copy of the iColumn-th
** entry in pEList.  (But leave references to the ROWID column
** unchanged.)
**
** This routine is part of the flattening procedure.  A subquery
** whose result set is defined by pEList appears as entry in the
** FROM clause of a SELECT such that the VDBE cursor assigned to that
** FORM clause entry is iTable.  This routine makes the necessary
** changes to pExpr so that it refers directly to the source table
** of the subquery rather the result set of the subquery.
*/
static Expr *substExpr(
  SubstContext *pSubst,  /* Description of the substitution */
  Expr *pExpr            /* Expr in which substitution occurs */
){
  if( pExpr==0 ) return 0;
  if( ExprHasProperty(pExpr, EP_OuterON|EP_InnerON)
   && pExpr->w.iJoin==pSubst->iTable
  ){
    testcase( ExprHasProperty(pExpr, EP_InnerON) );
    pExpr->w.iJoin = pSubst->iNewTable;
  }
  if( pExpr->op==TK_COLUMN
   && pExpr->iTable==pSubst->iTable
   && !ExprHasProperty(pExpr, EP_FixedCol)
  ){
#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
    if( pExpr->iColumn<0 ){
      pExpr->op = TK_NULL;
    }else
#endif
    {
      Expr *pNew;
      int iColumn;
      Expr *pCopy;
      Expr ifNullRow;
      iColumn = pExpr->iColumn;
      assert( iColumn>=0 );
      assert( pSubst->pEList!=0 && iColumn<pSubst->pEList->nExpr );
      assert( pExpr->pRight==0 );
      pCopy = pSubst->pEList->a[iColumn].pExpr;
      if( sqlite3ExprIsVector(pCopy) ){
        sqlite3VectorErrorMsg(pSubst->pParse, pCopy);
      }else{
        sqlite3 *db = pSubst->pParse->db;
        if( pSubst->isOuterJoin
         && (pCopy->op!=TK_COLUMN || pCopy->iTable!=pSubst->iNewTable)
        ){
          memset(&ifNullRow, 0, sizeof(ifNullRow));
          ifNullRow.op = TK_IF_NULL_ROW;
          ifNullRow.pLeft = pCopy;
          ifNullRow.iTable = pSubst->iNewTable;
          ifNullRow.iColumn = -99;
          ifNullRow.flags = EP_IfNullRow;
          pCopy = &ifNullRow;
        }
        testcase( ExprHasProperty(pCopy, EP_Subquery) );
        pNew = sqlite3ExprDup(db, pCopy, 0);
        if( db->mallocFailed ){
          sqlite3ExprDelete(db, pNew);
          return pExpr;
        }
        if( pSubst->isOuterJoin ){
          ExprSetProperty(pNew, EP_CanBeNull);
        }
        if( pNew->op==TK_TRUEFALSE ){
          pNew->u.iValue = sqlite3ExprTruthValue(pNew);

sqlite3.c  view on Meta::CPAN

  SrcList *pSrc;
  SrcItem *pItem;
  int i;
  if( !p ) return;
  pSubst->nSelDepth++;
  do{
    substExprList(pSubst, p->pEList);
    substExprList(pSubst, p->pGroupBy);
    substExprList(pSubst, p->pOrderBy);
    p->pHaving = substExpr(pSubst, p->pHaving);
    p->pWhere = substExpr(pSubst, p->pWhere);
    pSrc = p->pSrc;
    assert( pSrc!=0 );
    for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){
      if( pItem->fg.isSubquery ){
        substSelect(pSubst, pItem->u4.pSubq->pSelect, 1);
      }
      if( pItem->fg.isTabFunc ){
        substExprList(pSubst, pItem->u1.pFuncArg);
      }
    }
  }while( doPrior && (p = p->pPrior)!=0 );
  pSubst->nSelDepth--;
}
#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */

#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
/*
** pSelect is a SELECT statement and pSrcItem is one item in the FROM
** clause of that SELECT.
**
** This routine scans the entire SELECT statement and recomputes the
** pSrcItem->colUsed mask.
*/
static int recomputeColumnsUsedExpr(Walker *pWalker, Expr *pExpr){
  SrcItem *pItem;
  if( pExpr->op!=TK_COLUMN ) return WRC_Continue;
  pItem = pWalker->u.pSrcItem;
  if( pItem->iCursor!=pExpr->iTable ) return WRC_Continue;
  if( pExpr->iColumn<0 ) return WRC_Continue;
  pItem->colUsed |= sqlite3ExprColUsed(pExpr);
  return WRC_Continue;
}
static void recomputeColumnsUsed(
  Select *pSelect,                 /* The complete SELECT statement */
  SrcItem *pSrcItem                /* Which FROM clause item to recompute */
){
  Walker w;
  if( NEVER(pSrcItem->pSTab==0) ) return;
  memset(&w, 0, sizeof(w));
  w.xExprCallback = recomputeColumnsUsedExpr;
  w.xSelectCallback = sqlite3SelectWalkNoop;
  w.u.pSrcItem = pSrcItem;
  pSrcItem->colUsed = 0;
  sqlite3WalkSelect(&w, pSelect);
}
#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */

#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
/*
** Assign new cursor numbers to each of the items in pSrc. For each
** new cursor number assigned, set an entry in the aCsrMap[] array
** to map the old cursor number to the new:
**
**     aCsrMap[iOld+1] = iNew;
**
** The array is guaranteed by the caller to be large enough for all
** existing cursor numbers in pSrc.  aCsrMap[0] is the array size.
**
** If pSrc contains any sub-selects, call this routine recursively
** on the FROM clause of each such sub-select, with iExcept set to -1.
*/
static void srclistRenumberCursors(
  Parse *pParse,                  /* Parse context */
  int *aCsrMap,                   /* Array to store cursor mappings in */
  SrcList *pSrc,                  /* FROM clause to renumber */
  int iExcept                     /* FROM clause item to skip */
){
  int i;
  SrcItem *pItem;
  for(i=0, pItem=pSrc->a; i<pSrc->nSrc; i++, pItem++){
    if( i!=iExcept ){
      Select *p;
      assert( pItem->iCursor < aCsrMap[0] );
      if( !pItem->fg.isRecursive || aCsrMap[pItem->iCursor+1]==0 ){
        aCsrMap[pItem->iCursor+1] = pParse->nTab++;
      }
      pItem->iCursor = aCsrMap[pItem->iCursor+1];
      if( pItem->fg.isSubquery ){
        for(p=pItem->u4.pSubq->pSelect; p; p=p->pPrior){
          srclistRenumberCursors(pParse, aCsrMap, p->pSrc, -1);
        }
      }
    }
  }
}

/*
** *piCursor is a cursor number.  Change it if it needs to be mapped.
*/
static void renumberCursorDoMapping(Walker *pWalker, int *piCursor){
  int *aCsrMap = pWalker->u.aiCol;
  int iCsr = *piCursor;
  if( iCsr < aCsrMap[0] && aCsrMap[iCsr+1]>0 ){
    *piCursor = aCsrMap[iCsr+1];
  }
}

/*
** Expression walker callback used by renumberCursors() to update
** Expr objects to match newly assigned cursor numbers.
*/
static int renumberCursorsCb(Walker *pWalker, Expr *pExpr){
  int op = pExpr->op;
  if( op==TK_COLUMN || op==TK_IF_NULL_ROW ){
    renumberCursorDoMapping(pWalker, &pExpr->iTable);
  }
  if( ExprHasProperty(pExpr, EP_OuterON) ){
    renumberCursorDoMapping(pWalker, &pExpr->w.iJoin);
  }
  return WRC_Continue;
}

/*
** Assign a new cursor number to each cursor in the FROM clause (Select.pSrc)
** of the SELECT statement passed as the second argument, and to each
** cursor in the FROM clause of any FROM clause sub-selects, recursively.
** Except, do not assign a new cursor number to the iExcept'th element in
** the FROM clause of (*p). Update all expressions and other references
** to refer to the new cursor numbers.
**
** Argument aCsrMap is an array that may be used for temporary working
** space. Two guarantees are made by the caller:
**
**   * the array is larger than the largest cursor number used within the
**     select statement passed as an argument, and
**
**   * the array entries for all cursor numbers that do *not* appear in
**     FROM clauses of the select statement as described above are
**     initialized to zero.
*/
static void renumberCursors(
  Parse *pParse,                  /* Parse context */
  Select *p,                      /* Select to renumber cursors within */
  int iExcept,                    /* FROM clause item to skip */
  int *aCsrMap                    /* Working space */
){
  Walker w;
  srclistRenumberCursors(pParse, aCsrMap, p->pSrc, iExcept);
  memset(&w, 0, sizeof(w));
  w.u.aiCol = aCsrMap;
  w.xExprCallback = renumberCursorsCb;
  w.xSelectCallback = sqlite3SelectWalkNoop;
  sqlite3WalkSelect(&w, p);
}
#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */

/*
** If pSel is not part of a compound SELECT, return a pointer to its
** expression list. Otherwise, return a pointer to the expression list
** of the leftmost SELECT in the compound.
*/
static ExprList *findLeftmostExprlist(Select *pSel){
  while( pSel->pPrior ){
    pSel = pSel->pPrior;
  }
  return pSel->pEList;
}

/*
** Return true if any of the result-set columns in the compound query
** have incompatible affinities on one or more arms of the compound.
*/
static int compoundHasDifferentAffinities(Select *p){
  int ii;
  ExprList *pList;
  assert( p!=0 );
  assert( p->pEList!=0 );
  assert( p->pPrior!=0 );
  pList = p->pEList;
  for(ii=0; ii<pList->nExpr; ii++){
    char aff;
    Select *pSub1;
    assert( pList->a[ii].pExpr!=0 );
    aff = sqlite3ExprAffinity(pList->a[ii].pExpr);
    for(pSub1=p->pPrior; pSub1; pSub1=pSub1->pPrior){
      assert( pSub1->pEList!=0 );
      assert( pSub1->pEList->nExpr>ii );
      assert( pSub1->pEList->a[ii].pExpr!=0 );
      if( sqlite3ExprAffinity(pSub1->pEList->a[ii].pExpr)!=aff ){
        return 1;
      }
    }
  }
  return 0;
}

#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
/*
** This routine attempts to flatten subqueries as a performance optimization.
** This routine returns 1 if it makes changes and 0 if no flattening occurs.
**
** To understand the concept of flattening, consider the following
** query:

sqlite3.c  view on Meta::CPAN

**        an ORDER BY clause.  Ticket #3773.  We could relax this constraint
**        somewhat by saying that the terms of the ORDER BY clause must
**        appear as unmodified result columns in the outer query.  But we
**        have other optimizations in mind to deal with that case.
**
**  (21)  If the subquery uses LIMIT then the outer query may not be
**        DISTINCT.  (See ticket [752e1646fc]).
**
**  (22)  The subquery may not be a recursive CTE.
**
**  (23)  If the outer query is a recursive CTE, then the sub-query may not be
**        a compound query.  This restriction is because transforming the
**        parent to a compound query confuses the code that handles
**        recursive queries in multiSelect().
**
**  (**)  We no longer attempt to flatten aggregate subqueries.  Was:
**        The subquery may not be an aggregate that uses the built-in min() or
**        or max() functions.  (Without this restriction, a query like:
**        "SELECT x FROM (SELECT max(y), x FROM t1)" would not necessarily
**        return the value X for which Y was maximal.)
**
**  (25)  If either the subquery or the parent query contains a window
**        function in the select list or ORDER BY clause, flattening
**        is not attempted.
**
**  (26)  The subquery may not be the right operand of a RIGHT JOIN.
**        See also (3) for restrictions on LEFT JOIN.
**
**  (27)  The subquery may not contain a FULL or RIGHT JOIN unless it
**        is the first element of the parent query.  Two subcases:
**        (27a) the subquery is not a compound query.
**        (27b) the subquery is a compound query and the RIGHT JOIN occurs
**              in any arm of the compound query.  (See also (17g).)
**
**  (28)  The subquery is not a MATERIALIZED CTE.  (This is handled
**        in the caller before ever reaching this routine.)
**
**
** In this routine, the "p" parameter is a pointer to the outer query.
** The subquery is p->pSrc->a[iFrom].  isAgg is true if the outer query
** uses aggregates.
**
** If flattening is not attempted, this routine is a no-op and returns 0.
** If flattening is attempted this routine returns 1.
**
** All of the expression analysis must occur on both the outer query and
** the subquery before this routine runs.
*/
static int flattenSubquery(
  Parse *pParse,       /* Parsing context */
  Select *p,           /* The parent or outer SELECT statement */
  int iFrom,           /* Index in p->pSrc->a[] of the inner subquery */
  int isAgg            /* True if outer SELECT uses aggregate functions */
){
  const char *zSavedAuthContext = pParse->zAuthContext;
  Select *pParent;    /* Current UNION ALL term of the other query */
  Select *pSub;       /* The inner query or "subquery" */
  Select *pSub1;      /* Pointer to the rightmost select in sub-query */
  SrcList *pSrc;      /* The FROM clause of the outer query */
  SrcList *pSubSrc;   /* The FROM clause of the subquery */
  int iParent;        /* VDBE cursor number of the pSub result set temp table */
  int iNewParent = -1;/* Replacement table for iParent */
  int isOuterJoin = 0; /* True if pSub is the right side of a LEFT JOIN */
  int i;              /* Loop counter */
  Expr *pWhere;                    /* The WHERE clause */
  SrcItem *pSubitem;               /* The subquery */
  sqlite3 *db = pParse->db;
  Walker w;                        /* Walker to persist agginfo data */
  int *aCsrMap = 0;

  /* Check to see if flattening is permitted.  Return 0 if not.
  */
  assert( p!=0 );
  assert( p->pPrior==0 );
  if( OptimizationDisabled(db, SQLITE_QueryFlattener) ) return 0;
  pSrc = p->pSrc;
  assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
  pSubitem = &pSrc->a[iFrom];
  iParent = pSubitem->iCursor;
  assert( pSubitem->fg.isSubquery );
  pSub = pSubitem->u4.pSubq->pSelect;
  assert( pSub!=0 );

#ifndef SQLITE_OMIT_WINDOWFUNC
  if( p->pWin || pSub->pWin ) return 0;                  /* Restriction (25) */
#endif

  pSubSrc = pSub->pSrc;
  assert( pSubSrc );
  /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
  ** not arbitrary expressions, we allowed some combining of LIMIT and OFFSET
  ** because they could be computed at compile-time.  But when LIMIT and OFFSET
  ** became arbitrary expressions, we were forced to add restrictions (13)
  ** and (14). */
  if( pSub->pLimit && p->pLimit ) return 0;              /* Restriction (13) */
  if( pSub->pLimit && pSub->pLimit->pRight ) return 0;   /* Restriction (14) */
  if( (p->selFlags & SF_Compound)!=0 && pSub->pLimit ){
    return 0;                                            /* Restriction (15) */
  }
  if( pSubSrc->nSrc==0 ) return 0;                       /* Restriction (7)  */
  if( pSub->selFlags & SF_Distinct ) return 0;           /* Restriction (4)  */
  if( pSub->pLimit && (pSrc->nSrc>1 || isAgg) ){
     return 0;         /* Restrictions (8)(9) */
  }
  if( p->pOrderBy && pSub->pOrderBy ){
     return 0;                                           /* Restriction (11) */
  }
  if( isAgg && pSub->pOrderBy ) return 0;                /* Restriction (16) */
  if( pSub->pLimit && p->pWhere ) return 0;              /* Restriction (19) */
  if( pSub->pLimit && (p->selFlags & SF_Distinct)!=0 ){
     return 0;         /* Restriction (21) */
  }
  if( pSub->selFlags & (SF_Recursive) ){
    return 0; /* Restrictions (22) */
  }

  /*
  ** If the subquery is the right operand of a LEFT JOIN, then the
  ** subquery may not be a join itself (3a). Example of why this is not
  ** allowed:
  **

sqlite3.c  view on Meta::CPAN

    pSubitem->pSTab = 0;
    p->pOrderBy = 0;
    p->pPrior = 0;
    p->pLimit = 0;
    pNew = sqlite3SelectDup(db, p, 0);
    p->pLimit = pLimit;
    p->pOrderBy = pOrderBy;
    p->op = TK_ALL;
    pSubitem->pSTab = pItemTab;
    if( pNew==0 ){
      p->pPrior = pPrior;
    }else{
      pNew->selId = ++pParse->nSelect;
      if( aCsrMap && ALWAYS(db->mallocFailed==0) ){
        renumberCursors(pParse, pNew, iFrom, aCsrMap);
      }
      pNew->pPrior = pPrior;
      if( pPrior ) pPrior->pNext = pNew;
      pNew->pNext = p;
      p->pPrior = pNew;
      TREETRACE(0x4,pParse,p,("compound-subquery flattener"
                              " creates %u as peer\n",pNew->selId));
    }
    assert( pSubitem->fg.isSubquery==0 );
  }
  sqlite3DbFree(db, aCsrMap);
  if( db->mallocFailed ){
    assert( pSubitem->fg.fixedSchema==0 );
    assert( pSubitem->fg.isSubquery==0 );
    assert( pSubitem->u4.zDatabase==0 );
    sqlite3SrcItemAttachSubquery(pParse, pSubitem, pSub1, 0);
    return 1;
  }

  /* Defer deleting the Table object associated with the
  ** subquery until code generation is
  ** complete, since there may still exist Expr.pTab entries that
  ** refer to the subquery even after flattening.  Ticket #3346.
  **
  ** pSubitem->pSTab is always non-NULL by test restrictions and tests above.
  */
  if( ALWAYS(pSubitem->pSTab!=0) ){
    Table *pTabToDel = pSubitem->pSTab;
    if( pTabToDel->nTabRef==1 ){
      Parse *pToplevel = sqlite3ParseToplevel(pParse);
      sqlite3ParserAddCleanup(pToplevel, sqlite3DeleteTableGeneric, pTabToDel);
      testcase( pToplevel->earlyCleanup );
    }else{
      pTabToDel->nTabRef--;
    }
    pSubitem->pSTab = 0;
  }

  /* The following loop runs once for each term in a compound-subquery
  ** flattening (as described above).  If we are doing a different kind
  ** of flattening - a flattening other than a compound-subquery flattening -
  ** then this loop only runs once.
  **
  ** This loop moves all of the FROM elements of the subquery into the
  ** the FROM clause of the outer query.  Before doing this, remember
  ** the cursor number for the original outer query FROM element in
  ** iParent.  The iParent cursor will never be used.  Subsequent code
  ** will scan expressions looking for iParent references and replace
  ** those references with expressions that resolve to the subquery FROM
  ** elements we are now copying in.
  */
  pSub = pSub1;
  for(pParent=p; pParent; pParent=pParent->pPrior, pSub=pSub->pPrior){
    int nSubSrc;
    u8 jointype = pSubitem->fg.jointype;
    assert( pSub!=0 );
    pSubSrc = pSub->pSrc;     /* FROM clause of subquery */
    nSubSrc = pSubSrc->nSrc;  /* Number of terms in subquery FROM clause */
    pSrc = pParent->pSrc;     /* FROM clause of the outer query */

    /* The subquery uses a single slot of the FROM clause of the outer
    ** query.  If the subquery has more than one element in its FROM clause,
    ** then expand the outer query to make space for it to hold all elements
    ** of the subquery.
    **
    ** Example:
    **
    **    SELECT * FROM tabA, (SELECT * FROM sub1, sub2), tabB;
    **
    ** The outer query has 3 slots in its FROM clause.  One slot of the
    ** outer query (the middle slot) is used by the subquery.  The next
    ** block of code will expand the outer query FROM clause to 4 slots.
    ** The middle slot is expanded to two slots in order to make space
    ** for the two elements in the FROM clause of the subquery.
    */
    if( nSubSrc>1 ){
      pSrc = sqlite3SrcListEnlarge(pParse, pSrc, nSubSrc-1,iFrom+1);
      if( pSrc==0 ) break;
      pParent->pSrc = pSrc;
      pSubitem = &pSrc->a[iFrom];
    }

    /* Transfer the FROM clause terms from the subquery into the
    ** outer query.
    */
    iNewParent = pSubSrc->a[0].iCursor;
    for(i=0; i<nSubSrc; i++){
      SrcItem *pItem = &pSrc->a[i+iFrom];
      assert( pItem->fg.isTabFunc==0 );
      assert( pItem->fg.isSubquery
           || pItem->fg.fixedSchema
           || pItem->u4.zDatabase==0 );
      if( pItem->fg.isUsing ) sqlite3IdListDelete(db, pItem->u3.pUsing);
      *pItem = pSubSrc->a[i];
      pItem->fg.jointype |= (jointype & JT_LTORJ);
      memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
    }
    pSubitem->fg.jointype |= jointype;

    /* Now begin substituting subquery result set expressions for
    ** references to the iParent in the outer query.
    **
    ** Example:
    **
    **   SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
    **   \                     \_____________ subquery __________/          /
    **    \_____________________ outer query ______________________________/

sqlite3.c  view on Meta::CPAN

  Select *pSel;
  Table *pTab;

  assert( pFrom->fg.isSubquery );
  assert( pFrom->u4.pSubq!=0 );
  pSel = pFrom->u4.pSubq->pSelect;
  assert( pSel );
  pFrom->pSTab = pTab = sqlite3DbMallocZero(pParse->db, sizeof(Table));
  if( pTab==0 ) return SQLITE_NOMEM;
  pTab->nTabRef = 1;
  if( pFrom->zAlias ){
    pTab->zName = sqlite3DbStrDup(pParse->db, pFrom->zAlias);
  }else{
    pTab->zName = sqlite3MPrintf(pParse->db, "%!S", pFrom);
  }
  while( pSel->pPrior ){ pSel = pSel->pPrior; }
  sqlite3ColumnsFromExprList(pParse, pSel->pEList,&pTab->nCol,&pTab->aCol);
  pTab->iPKey = -1;
  pTab->eTabType = TABTYP_VIEW;
  pTab->nRowLogEst = 200; assert( 200==sqlite3LogEst(1048576) );
#ifndef SQLITE_ALLOW_ROWID_IN_VIEW
  /* The usual case - do not allow ROWID on a subquery */
  pTab->tabFlags |= TF_Ephemeral | TF_NoVisibleRowid;
#else
  /* Legacy compatibility mode */
  pTab->tabFlags |= TF_Ephemeral | sqlite3Config.mNoVisibleRowid;
#endif
  return pParse->nErr ? SQLITE_ERROR : SQLITE_OK;
}


/*
** Check the N SrcItem objects to the right of pBase.  (N might be zero!)
** If any of those SrcItem objects have a USING clause containing zName
** then return true.
**
** If N is zero, or none of the N SrcItem objects to the right of pBase
** contains a USING clause, or if none of the USING clauses contain zName,
** then return false.
*/
static int inAnyUsingClause(
  const char *zName, /* Name we are looking for */
  SrcItem *pBase,    /* The base SrcItem.  Looking at pBase[1] and following */
  int N              /* How many SrcItems to check */
){
  while( N>0 ){
    N--;
    pBase++;
    if( pBase->fg.isUsing==0 ) continue;
    if( NEVER(pBase->u3.pUsing==0) ) continue;
    if( sqlite3IdListIndex(pBase->u3.pUsing, zName)>=0 ) return 1;
  }
  return 0;
}


/*
** This routine is a Walker callback for "expanding" a SELECT statement.
** "Expanding" means to do the following:
**
**    (1)  Make sure VDBE cursor numbers have been assigned to every
**         element of the FROM clause.
**
**    (2)  Fill in the pTabList->a[].pTab fields in the SrcList that
**         defines FROM clause.  When views appear in the FROM clause,
**         fill pTabList->a[].pSelect with a copy of the SELECT statement
**         that implements the view.  A copy is made of the view's SELECT
**         statement so that we can freely modify or delete that statement
**         without worrying about messing up the persistent representation
**         of the view.
**
**    (3)  Add terms to the WHERE clause to accommodate the NATURAL keyword
**         on joins and the ON and USING clause of joins.
**
**    (4)  Scan the list of columns in the result set (pEList) looking
**         for instances of the "*" operator or the TABLE.* operator.
**         If found, expand each "*" to be every column in every table
**         and TABLE.* to be every column in TABLE.
**
*/
static int selectExpander(Walker *pWalker, Select *p){
  Parse *pParse = pWalker->pParse;
  int i, j, k, rc;
  SrcList *pTabList;
  ExprList *pEList;
  SrcItem *pFrom;
  sqlite3 *db = pParse->db;
  Expr *pE, *pRight, *pExpr;
  u16 selFlags = p->selFlags;
  u32 elistFlags = 0;

  p->selFlags |= SF_Expanded;
  if( db->mallocFailed  ){
    return WRC_Abort;
  }
  assert( p->pSrc!=0 );
  if( (selFlags & SF_Expanded)!=0 ){
    return WRC_Prune;
  }
  if( pWalker->eCode ){
    /* Renumber selId because it has been copied from a view */
    p->selId = ++pParse->nSelect;
  }
  pTabList = p->pSrc;
  pEList = p->pEList;
  if( pParse->pWith && (p->selFlags & SF_View) ){
    if( p->pWith==0 ){
      p->pWith = (With*)sqlite3DbMallocZero(db, SZ_WITH(1) );
      if( p->pWith==0 ){
        return WRC_Abort;
      }
    }
    p->pWith->bView = 1;
  }
  sqlite3WithPush(pParse, p->pWith, 0);

  /* Make sure cursor numbers have been assigned to all entries in
  ** the FROM clause of the SELECT statement.
  */
  sqlite3SrcListAssignCursors(pParse, pTabList);

  /* Look up every table named in the FROM clause of the select.  If
  ** an entry of the FROM clause is a subquery instead of a table or view,
  ** then create a transient table structure to describe the subquery.
  */
  for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
    Table *pTab;
    assert( pFrom->fg.isRecursive==0 || pFrom->pSTab!=0 );
    if( pFrom->pSTab ) continue;
    assert( pFrom->fg.isRecursive==0 );
    if( pFrom->zName==0 ){
#ifndef SQLITE_OMIT_SUBQUERY
      Select *pSel;
      assert( pFrom->fg.isSubquery && pFrom->u4.pSubq!=0 );
      pSel = pFrom->u4.pSubq->pSelect;
      /* A sub-query in the FROM clause of a SELECT */
      assert( pSel!=0 );
      assert( pFrom->pSTab==0 );
      if( sqlite3WalkSelect(pWalker, pSel) ) return WRC_Abort;
      if( sqlite3ExpandSubquery(pParse, pFrom) ) return WRC_Abort;
#endif
#ifndef SQLITE_OMIT_CTE
    }else if( (rc = resolveFromTermToCte(pParse, pWalker, pFrom))!=0 ){
      if( rc>1 ) return WRC_Abort;
      pTab = pFrom->pSTab;
      assert( pTab!=0 );
#endif
    }else{
      /* An ordinary table or view name in the FROM clause */
      assert( pFrom->pSTab==0 );
      pFrom->pSTab = pTab = sqlite3LocateTableItem(pParse, 0, pFrom);
      if( pTab==0 ) return WRC_Abort;
      if( pTab->nTabRef>=0xffff ){
        sqlite3ErrorMsg(pParse, "too many references to \"%s\": max 65535",
           pTab->zName);
        pFrom->pSTab = 0;
        return WRC_Abort;
      }
      pTab->nTabRef++;
      if( !IsVirtual(pTab) && cannotBeFunction(pParse, pFrom) ){
        return WRC_Abort;
      }
#if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_VIRTUALTABLE)
      if( !IsOrdinaryTable(pTab) ){
        i16 nCol;
        u8 eCodeOrig = pWalker->eCode;
        if( sqlite3ViewGetColumnNames(pParse, pTab) ) return WRC_Abort;
        assert( pFrom->fg.isSubquery==0 );
        if( IsView(pTab) ){
          if( (db->flags & SQLITE_EnableView)==0
           && pTab->pSchema!=db->aDb[1].pSchema
          ){
            sqlite3ErrorMsg(pParse, "access to view \"%s\" prohibited",
              pTab->zName);
          }
          sqlite3SrcItemAttachSubquery(pParse, pFrom, pTab->u.view.pSelect, 1);
        }

sqlite3.c  view on Meta::CPAN

  NameContext *pNC
){
  int i;
  assert( pAggInfo!=0 );
  assert( pAggInfo->iFirstReg==0 );
  pNC->ncFlags |= NC_InAggFunc;
  for(i=0; i<pAggInfo->nFunc; i++){
    Expr *pExpr = pAggInfo->aFunc[i].pFExpr;
    assert( pExpr->op==TK_FUNCTION || pExpr->op==TK_AGG_FUNCTION );
    assert( ExprUseXList(pExpr) );
    sqlite3ExprAnalyzeAggList(pNC, pExpr->x.pList);
    if( pExpr->pLeft ){
      assert( pExpr->pLeft->op==TK_ORDER );
      assert( ExprUseXList(pExpr->pLeft) );
      sqlite3ExprAnalyzeAggList(pNC, pExpr->pLeft->x.pList);
    }
#ifndef SQLITE_OMIT_WINDOWFUNC
    assert( !IsWindowFunc(pExpr) );
    if( ExprHasProperty(pExpr, EP_WinFunc) ){
      sqlite3ExprAnalyzeAggregates(pNC, pExpr->y.pWin->pFilter);
    }
#endif
  }
  pNC->ncFlags &= ~NC_InAggFunc;
}

/*
** An index on expressions is being used in the inner loop of an
** aggregate query with a GROUP BY clause.  This routine attempts
** to adjust the AggInfo object to take advantage of index and to
** perhaps use the index as a covering index.
**
*/
static void optimizeAggregateUseOfIndexedExpr(
  Parse *pParse,          /* Parsing context */
  Select *pSelect,        /* The SELECT statement being processed */
  AggInfo *pAggInfo,      /* The aggregate info */
  NameContext *pNC        /* Name context used to resolve agg-func args */
){
  assert( pAggInfo->iFirstReg==0 );
  assert( pSelect!=0 );
  assert( pSelect->pGroupBy!=0 );
  pAggInfo->nColumn = pAggInfo->nAccumulator;
  if( ALWAYS(pAggInfo->nSortingColumn>0) ){
    int mx = pSelect->pGroupBy->nExpr - 1;
    int j, k;
    for(j=0; j<pAggInfo->nColumn; j++){
      k = pAggInfo->aCol[j].iSorterColumn;
      if( k>mx ) mx = k;
    }
    pAggInfo->nSortingColumn = mx+1;
  }
  analyzeAggFuncArgs(pAggInfo, pNC);
#if TREETRACE_ENABLED
  if( sqlite3TreeTrace & 0x20 ){
    IndexedExpr *pIEpr;
    TREETRACE(0x20, pParse, pSelect,
        ("AggInfo (possibly) adjusted for Indexed Exprs\n"));
    sqlite3TreeViewSelect(0, pSelect, 0);
    for(pIEpr=pParse->pIdxEpr; pIEpr; pIEpr=pIEpr->pIENext){
      printf("data-cursor=%d index={%d,%d}\n",
          pIEpr->iDataCur, pIEpr->iIdxCur, pIEpr->iIdxCol);
      sqlite3TreeViewExpr(0, pIEpr->pExpr, 0);
    }
    printAggInfo(pAggInfo);
  }
#else
  UNUSED_PARAMETER(pSelect);
  UNUSED_PARAMETER(pParse);
#endif
}

/*
** Walker callback for aggregateConvertIndexedExprRefToColumn().
*/
static int aggregateIdxEprRefToColCallback(Walker *pWalker, Expr *pExpr){
  AggInfo *pAggInfo;
  struct AggInfo_col *pCol;
  UNUSED_PARAMETER(pWalker);
  if( pExpr->pAggInfo==0 ) return WRC_Continue;
  if( pExpr->op==TK_AGG_COLUMN ) return WRC_Continue;
  if( pExpr->op==TK_AGG_FUNCTION ) return WRC_Continue;
  if( pExpr->op==TK_IF_NULL_ROW ) return WRC_Continue;
  pAggInfo = pExpr->pAggInfo;
  if( NEVER(pExpr->iAgg>=pAggInfo->nColumn) ) return WRC_Continue;
  assert( pExpr->iAgg>=0 );
  pCol = &pAggInfo->aCol[pExpr->iAgg];
  pExpr->op = TK_AGG_COLUMN;
  pExpr->iTable = pCol->iTable;
  pExpr->iColumn = pCol->iColumn;
  ExprClearProperty(pExpr, EP_Skip|EP_Collate|EP_Unlikely);
  return WRC_Prune;
}

/*
** Convert every pAggInfo->aFunc[].pExpr such that any node within
** those expressions that has pAppInfo set is changed into a TK_AGG_COLUMN
** opcode.
*/
static void aggregateConvertIndexedExprRefToColumn(AggInfo *pAggInfo){
  int i;
  Walker w;
  memset(&w, 0, sizeof(w));
  w.xExprCallback = aggregateIdxEprRefToColCallback;
  for(i=0; i<pAggInfo->nFunc; i++){
    sqlite3WalkExpr(&w, pAggInfo->aFunc[i].pFExpr);
  }
}


/*
** Allocate a block of registers so that there is one register for each
** pAggInfo->aCol[] and pAggInfo->aFunc[] entry in pAggInfo.  The first
** register in this block is stored in pAggInfo->iFirstReg.
**
** This routine may only be called once for each AggInfo object.  Prior
** to calling this routine:
**
**     *  The aCol[] and aFunc[] arrays may be modified
**     *  The AggInfoColumnReg() and AggInfoFuncReg() macros may not be used
**

sqlite3.c  view on Meta::CPAN

  Vdbe *v = pParse->pVdbe;
  int i;
  struct AggInfo_func *pF;
  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
    ExprList *pList;
    assert( ExprUseXList(pF->pFExpr) );
    if( pParse->nErr ) return;
    pList = pF->pFExpr->x.pList;
    if( pF->iOBTab>=0 ){
      /* For an ORDER BY aggregate, calls to OP_AggStep were deferred.  Inputs
      ** were stored in emphermal table pF->iOBTab.  Here, we extract those
      ** inputs (in ORDER BY order) and make all calls to OP_AggStep
      ** before doing the OP_AggFinal call. */
      int iTop;        /* Start of loop for extracting columns */
      int nArg;        /* Number of columns to extract */
      int nKey;        /* Key columns to be skipped */
      int regAgg;      /* Extract into this array */
      int j;           /* Loop counter */

      assert( pF->pFunc!=0 );
      nArg = pList->nExpr;
      regAgg = sqlite3GetTempRange(pParse, nArg);

      if( pF->bOBPayload==0 ){
        nKey = 0;
      }else{
        assert( pF->pFExpr->pLeft!=0 );
        assert( ExprUseXList(pF->pFExpr->pLeft) );
        assert( pF->pFExpr->pLeft->x.pList!=0 );
        nKey = pF->pFExpr->pLeft->x.pList->nExpr;
        if( ALWAYS(!pF->bOBUnique) ) nKey++;
      }
      iTop = sqlite3VdbeAddOp1(v, OP_Rewind, pF->iOBTab); VdbeCoverage(v);
      for(j=nArg-1; j>=0; j--){
        sqlite3VdbeAddOp3(v, OP_Column, pF->iOBTab, nKey+j, regAgg+j);
      }
      if( pF->bUseSubtype ){
        int regSubtype = sqlite3GetTempReg(pParse);
        int iBaseCol = nKey + nArg + (pF->bOBPayload==0 && pF->bOBUnique==0);
        for(j=nArg-1; j>=0; j--){
          sqlite3VdbeAddOp3(v, OP_Column, pF->iOBTab, iBaseCol+j, regSubtype);
          sqlite3VdbeAddOp2(v, OP_SetSubtype, regSubtype, regAgg+j);
        }
        sqlite3ReleaseTempReg(pParse, regSubtype);
      }
      sqlite3VdbeAddOp3(v, OP_AggStep, 0, regAgg, AggInfoFuncReg(pAggInfo,i));
      sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF);
      sqlite3VdbeChangeP5(v, (u16)nArg);
      sqlite3VdbeAddOp2(v, OP_Next, pF->iOBTab, iTop+1); VdbeCoverage(v);
      sqlite3VdbeJumpHere(v, iTop);
      sqlite3ReleaseTempRange(pParse, regAgg, nArg);
    }
    sqlite3VdbeAddOp2(v, OP_AggFinal, AggInfoFuncReg(pAggInfo,i),
                      pList ? pList->nExpr : 0);
    sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF);
  }
}

/*
** Generate code that will update the accumulator memory cells for an
** aggregate based on the current cursor position.
**
** If regAcc is non-zero and there are no min() or max() aggregates
** in pAggInfo, then only populate the pAggInfo->nAccumulator accumulator
** registers if register regAcc contains 0. The caller will take care
** of setting and clearing regAcc.
**
** For an ORDER BY aggregate, the actual accumulator memory cell update
** is deferred until after all input rows have been received, so that they
** can be run in the requested order.  In that case, instead of invoking
** OP_AggStep to update the accumulator, just add the arguments that would
** have been passed into OP_AggStep into the sorting ephemeral table
** (along with the appropriate sort key).
*/
static void updateAccumulator(
  Parse *pParse,
  int regAcc,
  AggInfo *pAggInfo,
  int eDistinctType
){
  Vdbe *v = pParse->pVdbe;
  int i;
  int regHit = 0;
  int addrHitTest = 0;
  struct AggInfo_func *pF;
  struct AggInfo_col *pC;

  assert( pAggInfo->iFirstReg>0 );
  if( pParse->nErr ) return;
  pAggInfo->directMode = 1;
  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
    int nArg;
    int addrNext = 0;
    int regAgg;
    int regAggSz = 0;
    int regDistinct = 0;
    ExprList *pList;
    assert( ExprUseXList(pF->pFExpr) );
    assert( !IsWindowFunc(pF->pFExpr) );
    assert( pF->pFunc!=0 );
    pList = pF->pFExpr->x.pList;
    if( ExprHasProperty(pF->pFExpr, EP_WinFunc) ){
      Expr *pFilter = pF->pFExpr->y.pWin->pFilter;
      if( pAggInfo->nAccumulator
       && (pF->pFunc->funcFlags & SQLITE_FUNC_NEEDCOLL)
       && regAcc
      ){
        /* If regAcc==0, there there exists some min() or max() function
        ** without a FILTER clause that will ensure the magnet registers
        ** are populated. */
        if( regHit==0 ) regHit = ++pParse->nMem;
        /* If this is the first row of the group (regAcc contains 0), clear the
        ** "magnet" register regHit so that the accumulator registers
        ** are populated if the FILTER clause jumps over the the
        ** invocation of min() or max() altogether. Or, if this is not
        ** the first row (regAcc contains 1), set the magnet register so that
        ** the accumulators are not populated unless the min()/max() is invoked
        ** and indicates that they should be.  */
        sqlite3VdbeAddOp2(v, OP_Copy, regAcc, regHit);
      }
      addrNext = sqlite3VdbeMakeLabel(pParse);

sqlite3.c  view on Meta::CPAN

        ExprSetProperty(pWhere, EP_IntValue);

        assert( p->pWhere!=0 );
        pSub->pSrc->a[0].fg.fromExists = 1;
        pSub->pSrc->a[0].fg.jointype |= JT_CROSS;
        p->pSrc = sqlite3SrcListAppendList(pParse, p->pSrc, pSub->pSrc);
        if( pSubWhere ){
          p->pWhere = sqlite3PExpr(pParse, TK_AND, p->pWhere, pSubWhere);
          pSub->pWhere = 0;
        }
        pSub->pSrc = 0;
        sqlite3ParserAddCleanup(pParse, sqlite3SelectDeleteGeneric, pSub);
#if TREETRACE_ENABLED
        if( sqlite3TreeTrace & 0x100000 ){
          TREETRACE(0x100000,pParse,p,
                    ("After EXISTS-to-JOIN optimization:\n"));
          sqlite3TreeViewSelect(0, p, 0);
        }
#endif
        existsToJoin(pParse, p, pSubWhere);
      }
    }
  }
}

/*
** Type used for Walker callbacks by selectCheckOnClauses().
*/
typedef struct CheckOnCtx CheckOnCtx;
struct CheckOnCtx {
  SrcList *pSrc;                  /* SrcList for this context */
  int iJoin;                      /* Cursor numbers must be =< than this */
  CheckOnCtx *pParent;            /* Parent context */
};

/*
** True if the SrcList passed as the only argument contains at least
** one RIGHT or FULL JOIN. False otherwise.
*/
#define hasRightJoin(pSrc) (((pSrc)->a[0].fg.jointype & JT_LTORJ)!=0)

/*
** The xExpr callback for the search of invalid ON clause terms.
*/
static int selectCheckOnClausesExpr(Walker *pWalker, Expr *pExpr){
  CheckOnCtx *pCtx = pWalker->u.pCheckOnCtx;

  /* Check if pExpr is root or near-root of an ON clause constraint that needs
  ** to be checked to ensure that it does not refer to tables in its FROM
  ** clause to the right of itself. i.e. it is either:
  **
  **   + an ON clause on an OUTER join, or
  **   + an ON clause on an INNER join within a FROM that features at
  **     least one RIGHT or FULL join.
  */
  if( (ExprHasProperty(pExpr, EP_OuterON))
   || (ExprHasProperty(pExpr, EP_InnerON) && hasRightJoin(pCtx->pSrc))
  ){
    /* If CheckOnCtx.iJoin is already set, then fall through and process
    ** this expression node as normal. Or, if CheckOnCtx.iJoin is still 0,
    ** set it to the cursor number of the RHS of the join to which this
    ** ON expression was attached and then iterate through the entire
    ** expression.  */
    assert( pCtx->iJoin==0 || pCtx->iJoin==pExpr->w.iJoin );
    if( pCtx->iJoin==0 ){
      pCtx->iJoin = pExpr->w.iJoin;
      sqlite3WalkExprNN(pWalker, pExpr);
      pCtx->iJoin = 0;
      return WRC_Prune;
    }
  }

  if( pExpr->op==TK_COLUMN ){
    /* A column expression. Find the SrcList (if any) to which it refers.
    ** Then, if CheckOnCtx.iJoin indicates that this expression is part of an
    ** ON clause from that SrcList (i.e. if iJoin is non-zero), check that it
    ** does not refer to a table to the right of CheckOnCtx.iJoin. */
    do {
      SrcList *pSrc = pCtx->pSrc;
      int iTab = pExpr->iTable;
      if( iTab>=pSrc->a[0].iCursor && iTab<=pSrc->a[pSrc->nSrc-1].iCursor ){
        if( pCtx->iJoin && iTab>pCtx->iJoin ){
          sqlite3ErrorMsg(pWalker->pParse,
              "ON clause references tables to its right");
          return WRC_Abort;
        }
        break;
      }
      pCtx = pCtx->pParent;
    }while( pCtx );
  }
  return WRC_Continue;
}

/*
** The xSelect callback for the search of invalid ON clause terms.
*/
static int selectCheckOnClausesSelect(Walker *pWalker, Select *pSelect){
  CheckOnCtx *pCtx = pWalker->u.pCheckOnCtx;
  if( pSelect->pSrc==pCtx->pSrc || pSelect->pSrc->nSrc==0 ){
    return WRC_Continue;
  }else{
    CheckOnCtx sCtx;
    memset(&sCtx, 0, sizeof(sCtx));
    sCtx.pSrc = pSelect->pSrc;
    sCtx.pParent = pCtx;
    pWalker->u.pCheckOnCtx = &sCtx;
    sqlite3WalkSelect(pWalker, pSelect);
    pWalker->u.pCheckOnCtx = pCtx;
    pSelect->selFlags &= ~SF_OnToWhere;
    return WRC_Prune;
  }
}

/*
** Check all ON clauses in pSelect to verify that they do not reference
** columns to the right.
*/
static void selectCheckOnClauses(Parse *pParse, Select *pSelect){
  Walker w;
  CheckOnCtx sCtx;

sqlite3.c  view on Meta::CPAN

      if( distFlag!=0 && eDist!=WHERE_DISTINCT_NOOP ){
        struct AggInfo_func *pF = &pAggInfo->aFunc[0];
        fixDistinctOpenEph(pParse, eDist, pF->iDistinct, pF->iDistAddr);
      }
    } /* endif pGroupBy.  Begin aggregate queries without GROUP BY: */
    else {
      /* Aggregate functions without GROUP BY. tag-select-0820 */
      Table *pTab;
      if( (pTab = isSimpleCount(p, pAggInfo))!=0 ){
        /* tag-select-0821
        **
        ** If isSimpleCount() returns a pointer to a Table structure, then
        ** the SQL statement is of the form:
        **
        **   SELECT count(*) FROM <tbl>
        **
        ** where the Table structure returned represents table <tbl>.
        **
        ** This statement is so common that it is optimized specially. The
        ** OP_Count instruction is executed either on the intkey table that
        ** contains the data for table <tbl> or on one of its indexes. It
        ** is better to execute the op on an index, as indexes are almost
        ** always spread across less pages than their corresponding tables.
        */
        const int iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
        const int iCsr = pParse->nTab++;     /* Cursor to scan b-tree */
        Index *pIdx;                         /* Iterator variable */
        KeyInfo *pKeyInfo = 0;               /* Keyinfo for scanned index */
        Index *pBest = 0;                    /* Best index found so far */
        Pgno iRoot = pTab->tnum;             /* Root page of scanned b-tree */

        sqlite3CodeVerifySchema(pParse, iDb);
        sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);

        /* Search for the index that has the lowest scan cost.
        **
        ** (2011-04-15) Do not do a full scan of an unordered index.
        **
        ** (2013-10-03) Do not count the entries in a partial index.
        **
        ** In practice the KeyInfo structure will not be used. It is only
        ** passed to keep OP_OpenRead happy.
        */
        if( !HasRowid(pTab) ) pBest = sqlite3PrimaryKeyIndex(pTab);
        if( !p->pSrc->a[0].fg.notIndexed ){
          for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
            if( pIdx->bUnordered==0
             && pIdx->szIdxRow<pTab->szTabRow
             && pIdx->pPartIdxWhere==0
             && (!pBest || pIdx->szIdxRow<pBest->szIdxRow)
            ){
              pBest = pIdx;
            }
          }
        }
        if( pBest ){
          iRoot = pBest->tnum;
          pKeyInfo = sqlite3KeyInfoOfIndex(pParse, pBest);
        }

        /* Open a read-only cursor, execute the OP_Count, close the cursor. */
        sqlite3VdbeAddOp4Int(v, OP_OpenRead, iCsr, (int)iRoot, iDb, 1);
        if( pKeyInfo ){
          sqlite3VdbeChangeP4(v, -1, (char *)pKeyInfo, P4_KEYINFO);
        }
        assignAggregateRegisters(pParse, pAggInfo);
        sqlite3VdbeAddOp2(v, OP_Count, iCsr, AggInfoFuncReg(pAggInfo,0));
        sqlite3VdbeAddOp1(v, OP_Close, iCsr);
        explainSimpleCount(pParse, pTab, pBest);
      }else{
        /* The general case of an aggregate query without GROUP BY
        ** tag-select-0822 */
        int regAcc = 0;           /* "populate accumulators" flag */
        ExprList *pDistinct = 0;
        u16 distFlag = 0;
        int eDist;

        /* If there are accumulator registers but no min() or max() functions
        ** without FILTER clauses, allocate register regAcc. Register regAcc
        ** will contain 0 the first time the inner loop runs, and 1 thereafter.
        ** The code generated by updateAccumulator() uses this to ensure
        ** that the accumulator registers are (a) updated only once if
        ** there are no min() or max functions or (b) always updated for the
        ** first row visited by the aggregate, so that they are updated at
        ** least once even if the FILTER clause means the min() or max()
        ** function visits zero rows.  */
        if( pAggInfo->nAccumulator ){
          for(i=0; i<pAggInfo->nFunc; i++){
            if( ExprHasProperty(pAggInfo->aFunc[i].pFExpr, EP_WinFunc) ){
              continue;
            }
            if( pAggInfo->aFunc[i].pFunc->funcFlags&SQLITE_FUNC_NEEDCOLL ){
              break;
            }
          }
          if( i==pAggInfo->nFunc ){
            regAcc = ++pParse->nMem;
            sqlite3VdbeAddOp2(v, OP_Integer, 0, regAcc);
          }
        }else if( pAggInfo->nFunc==1 && pAggInfo->aFunc[0].iDistinct>=0 ){
          assert( ExprUseXList(pAggInfo->aFunc[0].pFExpr) );
          pDistinct = pAggInfo->aFunc[0].pFExpr->x.pList;
          distFlag = pDistinct ? (WHERE_WANT_DISTINCT|WHERE_AGG_DISTINCT) : 0;
        }
        assignAggregateRegisters(pParse, pAggInfo);

        /* This case runs if the aggregate has no GROUP BY clause.  The
        ** processing is much simpler since there is only a single row
        ** of output.
        */
        assert( p->pGroupBy==0 );
        resetAccumulator(pParse, pAggInfo);

        /* If this query is a candidate for the min/max optimization, then
        ** minMaxFlag will have been previously set to either
        ** WHERE_ORDERBY_MIN or WHERE_ORDERBY_MAX and pMinMaxOrderBy will
        ** be an appropriate ORDER BY expression for the optimization.
        */
        assert( minMaxFlag==WHERE_ORDERBY_NORMAL || pMinMaxOrderBy!=0 );
        assert( pMinMaxOrderBy==0 || pMinMaxOrderBy->nExpr==1 );

sqlite3.c  view on Meta::CPAN

** being updated.
*/
static int indexColumnIsBeingUpdated(
  Index *pIdx,      /* The index to check */
  int iCol,         /* Which column of the index to check */
  int *aXRef,       /* aXRef[j]>=0 if column j is being updated */
  int chngRowid     /* true if the rowid is being updated */
){
  i16 iIdxCol = pIdx->aiColumn[iCol];
  assert( iIdxCol!=XN_ROWID ); /* Cannot index rowid */
  if( iIdxCol>=0 ){
    return aXRef[iIdxCol]>=0;
  }
  assert( iIdxCol==XN_EXPR );
  assert( pIdx->aColExpr!=0 );
  assert( pIdx->aColExpr->a[iCol].pExpr!=0 );
  return sqlite3ExprReferencesUpdatedColumn(pIdx->aColExpr->a[iCol].pExpr,
                                            aXRef,chngRowid);
}

/*
** Check to see if index pIdx is a partial index whose conditional
** expression might change values due to an UPDATE.  Return true if
** the index is subject to change and false if the index is guaranteed
** to be unchanged.  This is an optimization.  False-positives are a
** performance degradation, but false-negatives can result in a corrupt
** index and incorrect answers.
**
** aXRef[j] will be non-negative if column j of the original table is
** being updated.  chngRowid will be true if the rowid of the table is
** being updated.
*/
static int indexWhereClauseMightChange(
  Index *pIdx,      /* The index to check */
  int *aXRef,       /* aXRef[j]>=0 if column j is being updated */
  int chngRowid     /* true if the rowid is being updated */
){
  if( pIdx->pPartIdxWhere==0 ) return 0;
  return sqlite3ExprReferencesUpdatedColumn(pIdx->pPartIdxWhere,
                                            aXRef, chngRowid);
}

/*
** Allocate and return a pointer to an expression of type TK_ROW with
** Expr.iColumn set to value (iCol+1). The resolver will modify the
** expression to be a TK_COLUMN reading column iCol of the first
** table in the source-list (pSrc->a[0]).
*/
static Expr *exprRowColumn(Parse *pParse, int iCol){
  Expr *pRet = sqlite3PExpr(pParse, TK_ROW, 0, 0);
  if( pRet ) pRet->iColumn = iCol+1;
  return pRet;
}

/*
** Assuming both the pLimit and pOrderBy parameters are NULL, this function
** generates VM code to run the query:
**
**   SELECT <other-columns>, pChanges FROM pTabList WHERE pWhere
**
** and write the results to the ephemeral table already opened as cursor
** iEph. None of pChanges, pTabList or pWhere are modified or consumed by
** this function, they must be deleted by the caller.
**
** Or, if pLimit and pOrderBy are not NULL, and pTab is not a view:
**
**   SELECT <other-columns>, pChanges FROM pTabList
**   WHERE pWhere
**   GROUP BY <other-columns>
**   ORDER BY pOrderBy LIMIT pLimit
**
** If pTab is a view, the GROUP BY clause is omitted.
**
** Exactly how results are written to table iEph, and exactly what
** the <other-columns> in the query above are is determined by the type
** of table pTabList->a[0].pTab.
**
** If the table is a WITHOUT ROWID table, then argument pPk must be its
** PRIMARY KEY. In this case <other-columns> are the primary key columns
** of the table, in order. The results of the query are written to ephemeral
** table iEph as index keys, using OP_IdxInsert.
**
** If the table is actually a view, then <other-columns> are all columns of
** the view. The results are written to the ephemeral table iEph as records
** with automatically assigned integer keys.
**
** If the table is a virtual or ordinary intkey table, then <other-columns>
** is its rowid. For a virtual table, the results are written to iEph as
** records with automatically assigned integer keys For intkey tables, the
** rowid value in <other-columns> is used as the integer key, and the
** remaining fields make up the table record.
*/
static void updateFromSelect(
  Parse *pParse,                  /* Parse context */
  int iEph,                       /* Cursor for open eph. table */
  Index *pPk,                     /* PK if table 0 is WITHOUT ROWID */
  ExprList *pChanges,             /* List of expressions to return */
  SrcList *pTabList,              /* List of tables to select from */
  Expr *pWhere,                   /* WHERE clause for query */
  ExprList *pOrderBy,             /* ORDER BY clause */
  Expr *pLimit                    /* LIMIT clause */
){
  int i;
  SelectDest dest;
  Select *pSelect = 0;
  ExprList *pList = 0;
  ExprList *pGrp = 0;
  Expr *pLimit2 = 0;
  ExprList *pOrderBy2 = 0;
  sqlite3 *db = pParse->db;
  Table *pTab = pTabList->a[0].pSTab;
  SrcList *pSrc;
  Expr *pWhere2;
  int eDest;

#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
  if( pOrderBy && pLimit==0 ) {
    sqlite3ErrorMsg(pParse, "ORDER BY without LIMIT on UPDATE");
    return;
  }
  pOrderBy2 = sqlite3ExprListDup(db, pOrderBy, 0);

sqlite3.c  view on Meta::CPAN

    for(i=0; i<pTab->nCol; i++){
      pList = sqlite3ExprListAppend(pParse, pList, exprRowColumn(pParse, i));
    }
    eDest = SRT_Table;
  }else{
    eDest = IsVirtual(pTab) ? SRT_Table : SRT_Upfrom;
    pList = sqlite3ExprListAppend(pParse, 0, sqlite3PExpr(pParse,TK_ROW,0,0));
#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
    if( pLimit ){
      pGrp = sqlite3ExprListAppend(pParse, 0, sqlite3PExpr(pParse,TK_ROW,0,0));
    }
#endif
  }
  assert( pChanges!=0 || pParse->db->mallocFailed );
  if( pChanges ){
    for(i=0; i<pChanges->nExpr; i++){
      pList = sqlite3ExprListAppend(pParse, pList,
          sqlite3ExprDup(db, pChanges->a[i].pExpr, 0)
      );
    }
  }
  pSelect = sqlite3SelectNew(pParse, pList,
      pSrc, pWhere2, pGrp, 0, pOrderBy2,
      SF_UFSrcCheck|SF_IncludeHidden|SF_UpdateFrom, pLimit2
  );
  if( pSelect ) pSelect->selFlags |= SF_OrderByReqd;
  sqlite3SelectDestInit(&dest, eDest, iEph);
  dest.iSDParm2 = (pPk ? pPk->nKeyCol : -1);
  sqlite3Select(pParse, pSelect, &dest);
  sqlite3SelectDelete(db, pSelect);
}

/*
** Process an UPDATE statement.
**
**   UPDATE OR IGNORE tbl SET a=b, c=d FROM tbl2... WHERE e<5 AND f NOT NULL;
**          \_______/ \_/     \______/      \_____/       \________________/
**           onError   |      pChanges         |                pWhere
**                     \_______________________/
**                               pTabList
*/
SQLITE_PRIVATE void sqlite3Update(
  Parse *pParse,         /* The parser context */
  SrcList *pTabList,     /* The table in which we should change things */
  ExprList *pChanges,    /* Things to be changed */
  Expr *pWhere,          /* The WHERE clause.  May be null */
  int onError,           /* How to handle constraint errors */
  ExprList *pOrderBy,    /* ORDER BY clause. May be null */
  Expr *pLimit,          /* LIMIT clause. May be null */
  Upsert *pUpsert        /* ON CONFLICT clause, or null */
){
  int i, j, k;           /* Loop counters */
  Table *pTab;           /* The table to be updated */
  int addrTop = 0;       /* VDBE instruction address of the start of the loop */
  WhereInfo *pWInfo = 0; /* Information about the WHERE clause */
  Vdbe *v;               /* The virtual database engine */
  Index *pIdx;           /* For looping over indices */
  Index *pPk;            /* The PRIMARY KEY index for WITHOUT ROWID tables */
  int nIdx;              /* Number of indices that need updating */
  int nAllIdx;           /* Total number of indexes */
  int iBaseCur;          /* Base cursor number */
  int iDataCur;          /* Cursor for the canonical data btree */
  int iIdxCur;           /* Cursor for the first index */
  sqlite3 *db;           /* The database structure */
  int *aRegIdx = 0;      /* Registers for to each index and the main table */
  int *aXRef = 0;        /* aXRef[i] is the index in pChanges->a[] of the
                         ** an expression for the i-th column of the table.
                         ** aXRef[i]==-1 if the i-th column is not changed. */
  u8 *aToOpen;           /* 1 for tables and indices to be opened */
  u8 chngPk;             /* PRIMARY KEY changed in a WITHOUT ROWID table */
  u8 chngRowid;          /* Rowid changed in a normal table */
  u8 chngKey;            /* Either chngPk or chngRowid */
  Expr *pRowidExpr = 0;  /* Expression defining the new record number */
  int iRowidExpr = -1;   /* Index of "rowid=" (or IPK) assignment in pChanges */
  AuthContext sContext;  /* The authorization context */
  NameContext sNC;       /* The name-context to resolve expressions in */
  int iDb;               /* Database containing the table being updated */
  int eOnePass;          /* ONEPASS_XXX value from where.c */
  int hasFK;             /* True if foreign key processing is required */
  int labelBreak;        /* Jump here to break out of UPDATE loop */
  int labelContinue;     /* Jump here to continue next step of UPDATE loop */
  int flags;             /* Flags for sqlite3WhereBegin() */

#ifndef SQLITE_OMIT_TRIGGER
  int isView;            /* True when updating a view (INSTEAD OF trigger) */
  Trigger *pTrigger;     /* List of triggers on pTab, if required */
  int tmask;             /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
#endif
  int newmask;           /* Mask of NEW.* columns accessed by BEFORE triggers */
  int iEph = 0;          /* Ephemeral table holding all primary key values */
  int nKey = 0;          /* Number of elements in regKey for WITHOUT ROWID */
  int aiCurOnePass[2];   /* The write cursors opened by WHERE_ONEPASS */
  int addrOpen = 0;      /* Address of OP_OpenEphemeral */
  int iPk = 0;           /* First of nPk cells holding PRIMARY KEY value */
  i16 nPk = 0;           /* Number of components of the PRIMARY KEY */
  int bReplace = 0;      /* True if REPLACE conflict resolution might happen */
  int bFinishSeek = 1;   /* The OP_FinishSeek opcode is needed */
  int nChangeFrom = 0;   /* If there is a FROM, pChanges->nExpr, else 0 */

  /* Register Allocations */
  int regRowCount = 0;   /* A count of rows changed */
  int regOldRowid = 0;   /* The old rowid */
  int regNewRowid = 0;   /* The new rowid */
  int regNew = 0;        /* Content of the NEW.* table in triggers */
  int regOld = 0;        /* Content of OLD.* table in triggers */
  int regRowSet = 0;     /* Rowset of rows to be updated */
  int regKey = 0;        /* composite PRIMARY KEY value */

  memset(&sContext, 0, sizeof(sContext));
  db = pParse->db;
  assert( db->pParse==pParse );
  if( pParse->nErr ){
    goto update_cleanup;
  }
  assert( db->mallocFailed==0 );

  /* Locate the table which we want to update.
  */
  pTab = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 ) goto update_cleanup;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);

  /* Figure out if we have any triggers and if the table being
  ** updated is a view.
  */
#ifndef SQLITE_OMIT_TRIGGER
  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges, &tmask);
  isView = IsView(pTab);
  assert( pTrigger || tmask==0 );
#else
# define pTrigger 0
# define isView 0
# define tmask 0
#endif
#ifdef SQLITE_OMIT_VIEW
# undef isView
# define isView 0
#endif

#if TREETRACE_ENABLED
  if( sqlite3TreeTrace & 0x10000 ){
    sqlite3TreeViewLine(0, "In sqlite3Update() at %s:%d", __FILE__, __LINE__);
    sqlite3TreeViewUpdate(pParse->pWith, pTabList, pChanges, pWhere,
                          onError, pOrderBy, pLimit, pUpsert, pTrigger);
  }
#endif

  /* If there was a FROM clause, set nChangeFrom to the number of expressions
  ** in the change-list. Otherwise, set it to 0. There cannot be a FROM
  ** clause if this function is being called to generate code for part of
  ** an UPSERT statement.  */
  nChangeFrom = (pTabList->nSrc>1) ? pChanges->nExpr : 0;
  assert( nChangeFrom==0 || pUpsert==0 );

#ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
  if( !isView && nChangeFrom==0 ){
    pWhere = sqlite3LimitWhere(
        pParse, pTabList, pWhere, pOrderBy, pLimit, "UPDATE"
    );
    pOrderBy = 0;
    pLimit = 0;
  }
#endif

  if( sqlite3ViewGetColumnNames(pParse, pTab) ){
    goto update_cleanup;
  }
  if( sqlite3IsReadOnly(pParse, pTab, pTrigger) ){
    goto update_cleanup;
  }

  /* Allocate a cursors for the main database table and for all indices.
  ** The index cursors might not be used, but if they are used they
  ** need to occur right after the database cursor.  So go ahead and
  ** allocate enough space, just in case.
  */
  iBaseCur = iDataCur = pParse->nTab++;
  iIdxCur = iDataCur+1;
  pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
  testcase( pPk!=0 && pPk!=pTab->pIndex );
  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
    if( pPk==pIdx ){
      iDataCur = pParse->nTab;
    }
    pParse->nTab++;
  }
  if( pUpsert ){
    /* On an UPSERT, reuse the same cursors already opened by INSERT */
    iDataCur = pUpsert->iDataCur;
    iIdxCur = pUpsert->iIdxCur;
    pParse->nTab = iBaseCur;
  }
  pTabList->a[0].iCursor = iDataCur;

  /* Allocate space for aXRef[], aRegIdx[], and aToOpen[].
  ** Initialize aXRef[] and aToOpen[] to their default values.
  */
  aXRef = sqlite3DbMallocRawNN(db, sizeof(int) * (pTab->nCol+nIdx+1) + nIdx+2 );
  if( aXRef==0 ) goto update_cleanup;
  aRegIdx = aXRef+pTab->nCol;
  aToOpen = (u8*)(aRegIdx+nIdx+1);
  memset(aToOpen, 1, nIdx+1);
  aToOpen[nIdx+1] = 0;
  for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;

  /* Initialize the name-context */
  memset(&sNC, 0, sizeof(sNC));
  sNC.pParse = pParse;
  sNC.pSrcList = pTabList;
  sNC.uNC.pUpsert = pUpsert;
  sNC.ncFlags = NC_UUpsert;

  /* Begin generating code. */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto update_cleanup;

  /* Resolve the column names in all the expressions of the
  ** of the UPDATE statement.  Also find the column index
  ** for each column to be updated in the pChanges array.  For each
  ** column to be updated, make sure we have authorization to change
  ** that column.
  */
  chngRowid = chngPk = 0;
  for(i=0; i<pChanges->nExpr; i++){
    /* If this is an UPDATE with a FROM clause, do not resolve expressions
    ** here. The call to sqlite3Select() below will do that. */
    if( nChangeFrom==0 && sqlite3ResolveExprNames(&sNC, pChanges->a[i].pExpr) ){
      goto update_cleanup;
    }
    j = sqlite3ColumnIndex(pTab, pChanges->a[i].zEName);
    if( j>=0 ){
      if( j==pTab->iPKey ){
        chngRowid = 1;
        pRowidExpr = pChanges->a[i].pExpr;
        iRowidExpr = i;
      }else if( pPk && (pTab->aCol[j].colFlags & COLFLAG_PRIMKEY)!=0 ){
        chngPk = 1;
      }
#ifndef SQLITE_OMIT_GENERATED_COLUMNS
      else if( pTab->aCol[j].colFlags & COLFLAG_GENERATED ){
        testcase( pTab->aCol[j].colFlags & COLFLAG_VIRTUAL );
        testcase( pTab->aCol[j].colFlags & COLFLAG_STORED );
        sqlite3ErrorMsg(pParse,
           "cannot UPDATE generated column \"%s\"",
           pTab->aCol[j].zCnName);
        goto update_cleanup;
      }
#endif

sqlite3.c  view on Meta::CPAN

  if( pTab->tabFlags & TF_HasGenerated ){
    int bProgress;
    testcase( pTab->tabFlags & TF_HasVirtual );
    testcase( pTab->tabFlags & TF_HasStored );
    do{
      bProgress = 0;
      for(i=0; i<pTab->nCol; i++){
        if( aXRef[i]>=0 ) continue;
        if( (pTab->aCol[i].colFlags & COLFLAG_GENERATED)==0 ) continue;
        if( sqlite3ExprReferencesUpdatedColumn(
                sqlite3ColumnExpr(pTab, &pTab->aCol[i]),
                 aXRef, chngRowid)
        ){
          aXRef[i] = 99999;
          bProgress = 1;
        }
      }
    }while( bProgress );
  }
#endif

  /* The SET expressions are not actually used inside the WHERE loop.
  ** So reset the colUsed mask. Unless this is a virtual table. In that
  ** case, set all bits of the colUsed mask (to ensure that the virtual
  ** table implementation makes all columns available).
  */
  pTabList->a[0].colUsed = IsVirtual(pTab) ? ALLBITS : 0;

  hasFK = sqlite3FkRequired(pParse, pTab, aXRef, chngKey);

  /* There is one entry in the aRegIdx[] array for each index on the table
  ** being updated.  Fill in aRegIdx[] with a register number that will hold
  ** the key for accessing each index.
  */
  if( onError==OE_Replace ) bReplace = 1;
  for(nAllIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nAllIdx++){
    int reg;
    if( chngKey || hasFK>1 || pIdx==pPk
     || indexWhereClauseMightChange(pIdx,aXRef,chngRowid)
    ){
      reg = ++pParse->nMem;
      pParse->nMem += pIdx->nColumn;
    }else{
      reg = 0;
      for(i=0; i<pIdx->nKeyCol; i++){
        if( indexColumnIsBeingUpdated(pIdx, i, aXRef, chngRowid) ){
          reg = ++pParse->nMem;
          pParse->nMem += pIdx->nColumn;
          if( onError==OE_Default && pIdx->onError==OE_Replace ){
            bReplace = 1;
          }
          break;
        }
      }
    }
    if( reg==0 ) aToOpen[nAllIdx+1] = 0;
    aRegIdx[nAllIdx] = reg;
  }
  aRegIdx[nAllIdx] = ++pParse->nMem;  /* Register storing the table record */
  if( bReplace ){
    /* If REPLACE conflict resolution might be invoked, open cursors on all
    ** indexes in case they are needed to delete records.  */
    memset(aToOpen, 1, nIdx+1);
  }

  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, pTrigger || hasFK, iDb);

  /* Allocate required registers. */
  if( !IsVirtual(pTab) ){
    /* For now, regRowSet and aRegIdx[nAllIdx] share the same register.
    ** If regRowSet turns out to be needed, then aRegIdx[nAllIdx] will be
    ** reallocated.  aRegIdx[nAllIdx] is the register in which the main
    ** table record is written.  regRowSet holds the RowSet for the
    ** two-pass update algorithm. */
    assert( aRegIdx[nAllIdx]==pParse->nMem );
    regRowSet = aRegIdx[nAllIdx];
    regOldRowid = regNewRowid = ++pParse->nMem;
    if( chngPk || pTrigger || hasFK ){
      regOld = pParse->nMem + 1;
      pParse->nMem += pTab->nCol;
    }
    if( chngKey || pTrigger || hasFK ){
      regNewRowid = ++pParse->nMem;
    }
    regNew = pParse->nMem + 1;
    pParse->nMem += pTab->nCol;
  }

  /* Start the view context. */
  if( isView ){
    sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
  }

  /* If we are trying to update a view, realize that view into
  ** an ephemeral table.
  */
#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
  if( nChangeFrom==0 && isView ){
    sqlite3MaterializeView(pParse, pTab,
        pWhere, pOrderBy, pLimit, iDataCur
    );
    pOrderBy = 0;
    pLimit = 0;
  }
#endif

  /* Resolve the column names in all the expressions in the
  ** WHERE clause.
  */
  if( nChangeFrom==0 && sqlite3ResolveExprNames(&sNC, pWhere) ){
    goto update_cleanup;
  }

#ifndef SQLITE_OMIT_VIRTUALTABLE
  /* Virtual tables must be handled separately */
  if( IsVirtual(pTab) ){
    updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
                       pWhere, onError);
    goto update_cleanup;
  }
#endif

  /* Jump to labelBreak to abandon further processing of this UPDATE */
  labelContinue = labelBreak = sqlite3VdbeMakeLabel(pParse);

  /* Not an UPSERT.  Normal processing.  Begin by
  ** initialize the count of updated rows */
  if( (db->flags&SQLITE_CountRows)!=0
   && !pParse->pTriggerTab
   && !pParse->nested
   && !pParse->bReturning
   && pUpsert==0
  ){
    regRowCount = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
  }

  if( nChangeFrom==0 && HasRowid(pTab) ){
    sqlite3VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldRowid);
    iEph = pParse->nTab++;
    addrOpen = sqlite3VdbeAddOp3(v, OP_OpenEphemeral, iEph, 0, regRowSet);
  }else{
    assert( pPk!=0 || HasRowid(pTab) );
    nPk = pPk ? pPk->nKeyCol : 0;
    iPk = pParse->nMem+1;
    pParse->nMem += nPk;
    pParse->nMem += nChangeFrom;
    regKey = ++pParse->nMem;
    if( pUpsert==0 ){
      int nEphCol = nPk + nChangeFrom + (isView ? pTab->nCol : 0);
      iEph = pParse->nTab++;
      if( pPk ) sqlite3VdbeAddOp3(v, OP_Null, 0, iPk, iPk+nPk-1);
      addrOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEph, nEphCol);
      if( pPk ){
        KeyInfo *pKeyInfo = sqlite3KeyInfoOfIndex(pParse, pPk);
        if( pKeyInfo ){
          pKeyInfo->nAllField = nEphCol;
          sqlite3VdbeAppendP4(v, pKeyInfo, P4_KEYINFO);
        }
      }
      if( nChangeFrom ){
        updateFromSelect(
            pParse, iEph, pPk, pChanges, pTabList, pWhere, pOrderBy, pLimit
        );
#ifndef SQLITE_OMIT_SUBQUERY
        if( isView ) iDataCur = iEph;
#endif
      }
    }
  }

  if( nChangeFrom ){
    sqlite3MultiWrite(pParse);
    eOnePass = ONEPASS_OFF;
    nKey = nPk;
    regKey = iPk;
  }else{
    if( pUpsert ){
      /* If this is an UPSERT, then all cursors have already been opened by
      ** the outer INSERT and the data cursor should be pointing at the row
      ** that is to be updated.  So bypass the code that searches for the
      ** row(s) to be updated.
      */
      pWInfo = 0;
      eOnePass = ONEPASS_SINGLE;
      sqlite3ExprIfFalse(pParse, pWhere, labelBreak, SQLITE_JUMPIFNULL);
      bFinishSeek = 0;
    }else{
      /* Begin the database scan.
      **
      ** Do not consider a single-pass strategy for a multi-row update if
      ** there is anything that might disrupt the cursor being used to do
      ** the UPDATE:
      **   (1) This is a nested UPDATE
      **   (2) There are triggers
      **   (3) There are FOREIGN KEY constraints
      **   (4) There are REPLACE conflict handlers
      **   (5) There are subqueries in the WHERE clause
      */
      flags = WHERE_ONEPASS_DESIRED;
      if( !pParse->nested
       && !pTrigger
       && !hasFK
       && !chngKey
       && !bReplace
       && (pWhere==0 || !ExprHasProperty(pWhere, EP_Subquery))
      ){
        flags |= WHERE_ONEPASS_MULTIROW;
      }
      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere,0,0,0,flags,iIdxCur);
      if( pWInfo==0 ) goto update_cleanup;

      /* A one-pass strategy that might update more than one row may not
      ** be used if any column of the index used for the scan is being
      ** updated. Otherwise, if there is an index on "b", statements like
      ** the following could create an infinite loop:
      **
      **   UPDATE t1 SET b=b+1 WHERE b>?
      **
      ** Fall back to ONEPASS_OFF if where.c has selected a ONEPASS_MULTI
      ** strategy that uses an index for which one or more columns are being
      ** updated.  */
      eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
      bFinishSeek = sqlite3WhereUsesDeferredSeek(pWInfo);
      if( eOnePass!=ONEPASS_SINGLE ){
        sqlite3MultiWrite(pParse);
        if( eOnePass==ONEPASS_MULTI ){
          int iCur = aiCurOnePass[1];
          if( iCur>=0 && iCur!=iDataCur && aToOpen[iCur-iBaseCur] ){
            eOnePass = ONEPASS_OFF;
          }
          assert( iCur!=iDataCur || !HasRowid(pTab) );
        }
      }
    }

    if( HasRowid(pTab) ){
      /* Read the rowid of the current row of the WHERE scan. In ONEPASS_OFF
      ** mode, write the rowid into the FIFO. In either of the one-pass modes,
      ** leave it in register regOldRowid.  */
      sqlite3VdbeAddOp2(v, OP_Rowid, iDataCur, regOldRowid);
      if( eOnePass==ONEPASS_OFF ){
        aRegIdx[nAllIdx] = ++pParse->nMem;
        sqlite3VdbeAddOp3(v, OP_Insert, iEph, regRowSet, regOldRowid);
      }else{
        if( ALWAYS(addrOpen) ) sqlite3VdbeChangeToNoop(v, addrOpen);
      }
    }else{
      /* Read the PK of the current row into an array of registers. In
      ** ONEPASS_OFF mode, serialize the array into a record and store it in
      ** the ephemeral table. Or, in ONEPASS_SINGLE or MULTI mode, change
      ** the OP_OpenEphemeral instruction to a Noop (the ephemeral table

sqlite3.c  view on Meta::CPAN

#endif

  /* Fire any BEFORE UPDATE triggers. This happens before constraints are
  ** verified. One could argue that this is wrong.
  */
  if( tmask&TRIGGER_BEFORE ){
    sqlite3TableAffinity(v, pTab, regNew);
    sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges,
        TRIGGER_BEFORE, pTab, regOldRowid, onError, labelContinue);

    if( !isView ){
      /* The row-trigger may have deleted the row being updated. In this
      ** case, jump to the next row. No updates or AFTER triggers are
      ** required. This behavior - what happens when the row being updated
      ** is deleted or renamed by a BEFORE trigger - is left undefined in the
      ** documentation.
      */
      if( pPk ){
        sqlite3VdbeAddOp4Int(v, OP_NotFound,iDataCur,labelContinue,regKey,nKey);
        VdbeCoverage(v);
      }else{
        sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue,regOldRowid);
        VdbeCoverage(v);
      }

      /* After-BEFORE-trigger-reload-loop:
      ** If it did not delete it, the BEFORE trigger may still have modified
      ** some of the columns of the row being updated. Load the values for
      ** all columns not modified by the update statement into their registers
      ** in case this has happened. Only unmodified columns are reloaded.
      ** The values computed for modified columns use the values before the
      ** BEFORE trigger runs.  See test case trigger1-18.0 (added 2018-04-26)
      ** for an example.
      */
      for(i=0, k=regNew; i<pTab->nCol; i++, k++){
        if( pTab->aCol[i].colFlags & COLFLAG_GENERATED ){
          if( pTab->aCol[i].colFlags & COLFLAG_VIRTUAL ) k--;
        }else if( aXRef[i]<0 && i!=pTab->iPKey ){
          sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, k);
        }
      }
#ifndef SQLITE_OMIT_GENERATED_COLUMNS
      if( pTab->tabFlags & TF_HasGenerated ){
        testcase( pTab->tabFlags & TF_HasVirtual );
        testcase( pTab->tabFlags & TF_HasStored );
        sqlite3ComputeGeneratedColumns(pParse, regNew, pTab);
      }
#endif
    }
  }

  if( !isView ){
    /* Do constraint checks. */
    assert( regOldRowid>0 );
    sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
        regNewRowid, regOldRowid, chngKey, onError, labelContinue, &bReplace,
        aXRef, 0);

    /* If REPLACE conflict handling may have been used, or if the PK of the
    ** row is changing, then the GenerateConstraintChecks() above may have
    ** moved cursor iDataCur. Reseek it. */
    if( bReplace || chngKey ){
      if( pPk ){
        sqlite3VdbeAddOp4Int(v, OP_NotFound,iDataCur,labelContinue,regKey,nKey);
      }else{
        sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue,regOldRowid);
      }
      VdbeCoverage(v);
    }

    /* Do FK constraint checks. */
    if( hasFK ){
      sqlite3FkCheck(pParse, pTab, regOldRowid, 0, aXRef, chngKey);
    }

    /* Delete the index entries associated with the current record.  */
    sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur, aRegIdx, -1);

    /* We must run the OP_FinishSeek opcode to resolve a prior
    ** OP_DeferredSeek if there is any possibility that there have been
    ** no OP_Column opcodes since the OP_DeferredSeek was issued.  But
    ** we want to avoid the OP_FinishSeek if possible, as running it
    ** costs CPU cycles. */
    if( bFinishSeek ){
      sqlite3VdbeAddOp1(v, OP_FinishSeek, iDataCur);
    }

    /* If changing the rowid value, or if there are foreign key constraints
    ** to process, delete the old record. Otherwise, add a noop OP_Delete
    ** to invoke the pre-update hook.
    **
    ** That (regNew==regnewRowid+1) is true is also important for the
    ** pre-update hook. If the caller invokes preupdate_new(), the returned
    ** value is copied from memory cell (regNewRowid+1+iCol), where iCol
    ** is the column index supplied by the user.
    */
    assert( regNew==regNewRowid+1 );
#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
    sqlite3VdbeAddOp3(v, OP_Delete, iDataCur,
        OPFLAG_ISUPDATE | ((hasFK>1 || chngKey) ? 0 : OPFLAG_ISNOOP),
        regNewRowid
    );
    if( eOnePass==ONEPASS_MULTI ){
      assert( hasFK==0 && chngKey==0 );
      sqlite3VdbeChangeP5(v, OPFLAG_SAVEPOSITION);
    }
    if( !pParse->nested ){
      sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
    }
#else
    if( hasFK>1 || chngKey ){
      sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, 0);
    }
#endif

    if( hasFK ){
      sqlite3FkCheck(pParse, pTab, 0, regNewRowid, aXRef, chngKey);
    }

    /* Insert the new index entries and the new record. */
    sqlite3CompleteInsertion(

sqlite3.c  view on Meta::CPAN

        ** have redundant ON CONFLICT clauses. */
        pUpsert->isDup = 1;
      }
      break;
    }
    if( pUpsert->pUpsertIdx==0 ){
      char zWhich[16];
      if( nClause==0 && pUpsert->pNextUpsert==0 ){
        zWhich[0] = 0;
      }else{
        sqlite3_snprintf(sizeof(zWhich),zWhich,"%r ", nClause+1);
      }
      sqlite3ErrorMsg(pParse, "%sON CONFLICT clause does not match any "
                              "PRIMARY KEY or UNIQUE constraint", zWhich);
      return SQLITE_ERROR;
    }
  }
  return SQLITE_OK;
}

/*
** Return true if pUpsert is the last ON CONFLICT clause with a
** conflict target, or if pUpsert is followed by another ON CONFLICT
** clause that targets the INTEGER PRIMARY KEY.
*/
SQLITE_PRIVATE int sqlite3UpsertNextIsIPK(Upsert *pUpsert){
  Upsert *pNext;
  if( NEVER(pUpsert==0) ) return 0;
  pNext = pUpsert->pNextUpsert;
  while( 1 /*exit-by-return*/ ){
    if( pNext==0 ) return 1;
    if( pNext->pUpsertTarget==0 ) return 1;
    if( pNext->pUpsertIdx==0 ) return 1;
    if( !pNext->isDup ) return 0;
    pNext = pNext->pNextUpsert;
  }
  return 0;
}

/*
** Given the list of ON CONFLICT clauses described by pUpsert, and
** a particular index pIdx, return a pointer to the particular ON CONFLICT
** clause that applies to the index.  Or, if the index is not subject to
** any ON CONFLICT clause, return NULL.
*/
SQLITE_PRIVATE Upsert *sqlite3UpsertOfIndex(Upsert *pUpsert, Index *pIdx){
  while(
      pUpsert
   && pUpsert->pUpsertTarget!=0
   && pUpsert->pUpsertIdx!=pIdx
  ){
     pUpsert = pUpsert->pNextUpsert;
  }
  return pUpsert;
}

/*
** Generate bytecode that does an UPDATE as part of an upsert.
**
** If pIdx is NULL, then the UNIQUE constraint that failed was the IPK.
** In this case parameter iCur is a cursor open on the table b-tree that
** currently points to the conflicting table row. Otherwise, if pIdx
** is not NULL, then pIdx is the constraint that failed and iCur is a
** cursor points to the conflicting row.
*/
SQLITE_PRIVATE void sqlite3UpsertDoUpdate(
  Parse *pParse,        /* The parsing and code-generating context */
  Upsert *pUpsert,      /* The ON CONFLICT clause for the upsert */
  Table *pTab,          /* The table being updated */
  Index *pIdx,          /* The UNIQUE constraint that failed */
  int iCur              /* Cursor for pIdx (or pTab if pIdx==NULL) */
){
  Vdbe *v = pParse->pVdbe;
  sqlite3 *db = pParse->db;
  SrcList *pSrc;            /* FROM clause for the UPDATE */
  int iDataCur;
  int i;
  Upsert *pTop = pUpsert;

  assert( v!=0 );
  assert( pUpsert!=0 );
  iDataCur = pUpsert->iDataCur;
  pUpsert = sqlite3UpsertOfIndex(pTop, pIdx);
  VdbeNoopComment((v, "Begin DO UPDATE of UPSERT"));
  if( pIdx && iCur!=iDataCur ){
    if( HasRowid(pTab) ){
      int regRowid = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp2(v, OP_IdxRowid, iCur, regRowid);
      sqlite3VdbeAddOp3(v, OP_SeekRowid, iDataCur, 0, regRowid);
      VdbeCoverage(v);
      sqlite3ReleaseTempReg(pParse, regRowid);
    }else{
      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
      int nPk = pPk->nKeyCol;
      int iPk = pParse->nMem+1;
      pParse->nMem += nPk;
      for(i=0; i<nPk; i++){
        int k;
        assert( pPk->aiColumn[i]>=0 );
        k = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[i]);
        sqlite3VdbeAddOp3(v, OP_Column, iCur, k, iPk+i);
        VdbeComment((v, "%s.%s", pIdx->zName,
                    pTab->aCol[pPk->aiColumn[i]].zCnName));
      }
      sqlite3VdbeVerifyAbortable(v, OE_Abort);
      i = sqlite3VdbeAddOp4Int(v, OP_Found, iDataCur, 0, iPk, nPk);
      VdbeCoverage(v);
      sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CORRUPT, OE_Abort, 0,
            "corrupt database", P4_STATIC);
      sqlite3MayAbort(pParse);
      sqlite3VdbeJumpHere(v, i);
    }
  }
  /* pUpsert does not own pTop->pUpsertSrc - the outer INSERT statement does.
  ** So we have to make a copy before passing it down into sqlite3Update() */
  pSrc = sqlite3SrcListDup(db, pTop->pUpsertSrc, 0);
  /* excluded.* columns of type REAL need to be converted to a hard real */
  for(i=0; i<pTab->nCol; i++){
    if( pTab->aCol[i].affinity==SQLITE_AFF_REAL ){
      sqlite3VdbeAddOp1(v, OP_RealAffinity, pTop->regData+i);
    }
  }
  sqlite3Update(pParse, pSrc, sqlite3ExprListDup(db,pUpsert->pUpsertSet,0),
      sqlite3ExprDup(db,pUpsert->pUpsertWhere,0), OE_Abort, 0, 0, pUpsert);

sqlite3.c  view on Meta::CPAN

** a separate source file for easier editing.
*/
#ifndef SQLITE_WHEREINT_H
#define SQLITE_WHEREINT_H


/* Forward references
*/
typedef struct WhereClause WhereClause;
typedef struct WhereMaskSet WhereMaskSet;
typedef struct WhereOrInfo WhereOrInfo;
typedef struct WhereAndInfo WhereAndInfo;
typedef struct WhereLevel WhereLevel;
typedef struct WhereLoop WhereLoop;
typedef struct WherePath WherePath;
typedef struct WhereTerm WhereTerm;
typedef struct WhereLoopBuilder WhereLoopBuilder;
typedef struct WhereScan WhereScan;
typedef struct WhereOrCost WhereOrCost;
typedef struct WhereOrSet WhereOrSet;
typedef struct WhereMemBlock WhereMemBlock;
typedef struct WhereRightJoin WhereRightJoin;

/*
** This object is a header on a block of allocated memory that will be
** automatically freed when its WInfo object is destructed.
*/
struct WhereMemBlock {
  WhereMemBlock *pNext;      /* Next block in the chain */
  u64 sz;                    /* Bytes of space */
};

/*
** Extra information attached to a WhereLevel that is a RIGHT JOIN.
*/
struct WhereRightJoin {
  int iMatch;          /* Cursor used to determine prior matched rows */
  int regBloom;        /* Bloom filter for iRJMatch */
  int regReturn;       /* Return register for the interior subroutine */
  int addrSubrtn;      /* Starting address for the interior subroutine */
  int endSubrtn;       /* The last opcode in the interior subroutine */
};

/*
** This object contains information needed to implement a single nested
** loop in WHERE clause.
**
** Contrast this object with WhereLoop.  This object describes the
** implementation of the loop.  WhereLoop describes the algorithm.
** This object contains a pointer to the WhereLoop algorithm as one of
** its elements.
**
** The WhereInfo object contains a single instance of this object for
** each term in the FROM clause (which is to say, for each of the
** nested loops as implemented).  The order of WhereLevel objects determines
** the loop nested order, with WhereInfo.a[0] being the outer loop and
** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop.
*/
struct WhereLevel {
  int iLeftJoin;        /* Memory cell used to implement LEFT OUTER JOIN */
  int iTabCur;          /* The VDBE cursor used to access the table */
  int iIdxCur;          /* The VDBE cursor used to access pIdx */
  int addrBrk;          /* Jump here to break out of the loop */
  int addrHalt;         /* Abort the query due to empty table or similar */
  int addrNxt;          /* Jump here to start the next IN combination */
  int addrSkip;         /* Jump here for next iteration of skip-scan */
  int addrCont;         /* Jump here to continue with the next loop cycle */
  int addrFirst;        /* First instruction of interior of the loop */
  int addrBody;         /* Beginning of the body of this loop */
  int regBignull;       /* big-null flag reg. True if a NULL-scan is needed */
  int addrBignull;      /* Jump here for next part of big-null scan */
#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
  u32 iLikeRepCntr;     /* LIKE range processing counter register (times 2) */
  int addrLikeRep;      /* LIKE range processing address */
#endif
  int regFilter;        /* Bloom filter */
  WhereRightJoin *pRJ;  /* Extra information for RIGHT JOIN */
  u8 iFrom;             /* Which entry in the FROM clause */
  u8 op, p3, p5;        /* Opcode, P3 & P5 of the opcode that ends the loop */
  int p1, p2;           /* Operands of the opcode used to end the loop */
  union {               /* Information that depends on pWLoop->wsFlags */
    struct {
      int nIn;              /* Number of entries in aInLoop[] */
      struct InLoop {
        int iCur;              /* The VDBE cursor used by this IN operator */
        int addrInTop;         /* Top of the IN loop */
        int iBase;             /* Base register of multi-key index record */
        int nPrefix;           /* Number of prior entries in the key */
        u8 eEndLoopOp;         /* IN Loop terminator. OP_Next or OP_Prev */
      } *aInLoop;           /* Information about each nested IN operator */
    } in;                 /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */
    Index *pCoveringIdx;  /* Possible covering index for WHERE_MULTI_OR */
  } u;
  struct WhereLoop *pWLoop;  /* The selected WhereLoop object */
  Bitmask notReady;          /* FROM entries not usable at this level */
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
  int addrVisit;        /* Address at which row is visited */
#endif
};

/*
** Each instance of this object represents an algorithm for evaluating one
** term of a join.  Every term of the FROM clause will have at least
** one corresponding WhereLoop object (unless INDEXED BY constraints
** prevent a query solution - which is an error) and many terms of the
** FROM clause will have multiple WhereLoop objects, each describing a
** potential way of implementing that FROM-clause term, together with
** dependencies and cost estimates for using the chosen algorithm.
**
** Query planning consists of building up a collection of these WhereLoop
** objects, then computing a particular sequence of WhereLoop objects, with
** one WhereLoop object per FROM clause term, that satisfy all dependencies
** and that minimize the overall cost.
*/
struct WhereLoop {
  Bitmask prereq;       /* Bitmask of other loops that must run first */
  Bitmask maskSelf;     /* Bitmask identifying table iTab */
#ifdef SQLITE_DEBUG
  char cId;             /* Symbolic ID of this loop for debugging use */
#endif
  u8 iTab;              /* Position in FROM clause of table for this loop */
  u8 iSortIdx;          /* Sorting index number.  0==None */
  LogEst rSetup;        /* One-time setup cost (ex: create transient index) */
  LogEst rRun;          /* Cost of running each loop */
  LogEst nOut;          /* Estimated number of output rows */
  union {
    struct {               /* Information for internal btree tables */
      u16 nEq;               /* Number of equality constraints */
      u16 nBtm;              /* Size of BTM vector */
      u16 nTop;              /* Size of TOP vector */
      u16 nDistinctCol;      /* Index columns used to sort for DISTINCT */
      Index *pIndex;         /* Index used, or NULL */
      ExprList *pOrderBy;    /* ORDER BY clause if this is really a subquery */
    } btree;
    struct {               /* Information for virtual tables */
      int idxNum;            /* Index number */
      u32 needFree : 1;      /* True if sqlite3_free(idxStr) is needed */
      u32 bOmitOffset : 1;   /* True to let virtual table handle offset */
      u32 bIdxNumHex : 1;    /* Show idxNum as hex in EXPLAIN QUERY PLAN */
      i8 isOrdered;          /* True if satisfies ORDER BY */
      u16 omitMask;          /* Terms that may be omitted */
      char *idxStr;          /* Index identifier string */
      u32 mHandleIn;         /* Terms to handle as IN(...) instead of == */
    } vtab;
  } u;

sqlite3.c  view on Meta::CPAN

  Bitmask prereq;     /* Prerequisites */
  LogEst rRun;        /* Cost of running this subquery */
  LogEst nOut;        /* Number of outputs for this subquery */
};

/* The WhereOrSet object holds a set of possible WhereOrCosts that
** correspond to the subquery(s) of OR-clause processing.  Only the
** best N_OR_COST elements are retained.
*/
#define N_OR_COST 3
struct WhereOrSet {
  u16 n;                      /* Number of valid a[] entries */
  WhereOrCost a[N_OR_COST];   /* Set of best costs */
};

/*
** Each instance of this object holds a sequence of WhereLoop objects
** that implement some or all of a query plan.
**
** Think of each WhereLoop object as a node in a graph with arcs
** showing dependencies and costs for travelling between nodes.  (That is
** not a completely accurate description because WhereLoop costs are a
** vector, not a scalar, and because dependencies are many-to-one, not
** one-to-one as are graph nodes.  But it is a useful visualization aid.)
** Then a WherePath object is a path through the graph that visits some
** or all of the WhereLoop objects once.
**
** The "solver" works by creating the N best WherePath objects of length
** 1.  Then using those as a basis to compute the N best WherePath objects
** of length 2.  And so forth until the length of WherePaths equals the
** number of nodes in the FROM clause.  The best (lowest cost) WherePath
** at the end is the chosen query plan.
*/
struct WherePath {
  Bitmask maskLoop;     /* Bitmask of all WhereLoop objects in this path */
  Bitmask revLoop;      /* aLoop[]s that should be reversed for ORDER BY */
  LogEst nRow;          /* Estimated number of rows generated by this path */
  LogEst rCost;         /* Total cost of this path */
  LogEst rUnsort;       /* Total cost of this path ignoring sorting costs */
  i8 isOrdered;         /* No. of ORDER BY terms satisfied. -1 for unknown */
  WhereLoop **aLoop;    /* Array of WhereLoop objects implementing this path */
};

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by AND operators,
** usually, or sometimes subexpressions separated by OR.
**
** All WhereTerms are collected into a single WhereClause structure.
** The following identity holds:
**
**        WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm
**
** When a term is of the form:
**
**              X <op> <expr>
**
** where X is a column name and <op> is one of certain operators,
** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the
** cursor number and column number for X.  WhereTerm.eOperator records
** the <op> using a bitmask encoding defined by WO_xxx below.  The
** use of a bitmask encoding for the operator allows us to search
** quickly for terms that match any of several different operators.
**
** A WhereTerm might also be two or more subterms connected by OR:
**
**         (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR ....
**
** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR
** and the WhereTerm.u.pOrInfo field points to auxiliary information that
** is collected about the OR clause.
**
** If a term in the WHERE clause does not match either of the two previous
** categories, then eOperator==0.  The WhereTerm.pExpr field is still set
** to the original subexpression content and wtFlags is set up appropriately
** but no other fields in the WhereTerm object are meaningful.
**
** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers,
** but they do so indirectly.  A single WhereMaskSet structure translates
** cursor number into bits and the translated bit is stored in the prereq
** fields.  The translation is used in order to maximize the number of
** bits that will fit in a Bitmask.  The VDBE cursor numbers might be
** spread out over the non-negative integers.  For example, the cursor
** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45.  The WhereMaskSet
** translates these sparse cursor numbers into consecutive integers
** beginning with 0 in order to make the best possible use of the available
** bits in the Bitmask.  So, in the example above, the cursor numbers
** would be mapped into integers 0 through 7.
**
** The number of terms in a join is limited by the number of bits
** in prereqRight and prereqAll.  The default is 64 bits, hence SQLite
** is only able to process joins with 64 or fewer tables.
*/
struct WhereTerm {
  Expr *pExpr;            /* Pointer to the subexpression that is this term */
  WhereClause *pWC;       /* The clause this term is part of */
  LogEst truthProb;       /* Probability of truth for this expression */
  u16 wtFlags;            /* TERM_xxx bit flags.  See below */
  u16 eOperator;          /* A WO_xx value describing <op> */
  u8 nChild;              /* Number of children that must disable us */
  u8 eMatchOp;            /* Op for vtab MATCH/LIKE/GLOB/REGEXP terms */
  int iParent;            /* Disable pWC->a[iParent] when this term disabled */
  int leftCursor;         /* Cursor number of X in "X <op> <expr>" */
#ifdef SQLITE_DEBUG
  int iTerm;              /* Which WhereTerm is this, for debug purposes */
#endif
  union {
    struct {
      int leftColumn;         /* Column number of X in "X <op> <expr>" */
      int iField;             /* Field in (?,?,?) IN (SELECT...) vector */
    } x;                    /* Opcode other than OP_OR or OP_AND */
    WhereOrInfo *pOrInfo;   /* Extra information if (eOperator & WO_OR)!=0 */
    WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */
  } u;
  Bitmask prereqRight;    /* Bitmask of tables used by pExpr->pRight */
  Bitmask prereqAll;      /* Bitmask of tables referenced by pExpr */
};

/*
** Allowed values of WhereTerm.wtFlags
*/
#define TERM_DYNAMIC    0x0001 /* Need to call sqlite3ExprDelete(db, pExpr) */
#define TERM_VIRTUAL    0x0002 /* Added by the optimizer.  Do not code */
#define TERM_CODED      0x0004 /* This term is already coded */
#define TERM_COPIED     0x0008 /* Has a child */
#define TERM_ORINFO     0x0010 /* Need to free the WhereTerm.u.pOrInfo object */
#define TERM_ANDINFO    0x0020 /* Need to free the WhereTerm.u.pAndInfo obj */
#define TERM_OK         0x0040 /* Used during OR-clause processing */
#define TERM_VNULL      0x0080 /* Manufactured x>NULL or x<=NULL term */
#define TERM_LIKEOPT    0x0100 /* Virtual terms from the LIKE optimization */
#define TERM_LIKECOND   0x0200 /* Conditionally this LIKE operator term */
#define TERM_LIKE       0x0400 /* The original LIKE operator */
#define TERM_IS         0x0800 /* Term.pExpr is an IS operator */
#define TERM_VARSELECT  0x1000 /* Term.pExpr contains a correlated sub-query */
#define TERM_HEURTRUTH  0x2000 /* Heuristic truthProb used */
#ifdef SQLITE_ENABLE_STAT4
#  define TERM_HIGHTRUTH  0x4000 /* Term excludes few rows */
#else
#  define TERM_HIGHTRUTH  0      /* Only used with STAT4 */
#endif
#define TERM_SLICE      0x8000 /* One slice of a row-value/vector comparison */

/*
** An instance of the WhereScan object is used as an iterator for locating
** terms in the WHERE clause that are useful to the query planner.
*/
struct WhereScan {
  WhereClause *pOrigWC;      /* Original, innermost WhereClause */
  WhereClause *pWC;          /* WhereClause currently being scanned */
  const char *zCollName;     /* Required collating sequence, if not NULL */
  Expr *pIdxExpr;            /* Search for this index expression */
  int k;                     /* Resume scanning at this->pWC->a[this->k] */
  u32 opMask;                /* Acceptable operators */
  char idxaff;               /* Must match this affinity, if zCollName!=NULL */
  unsigned char iEquiv;      /* Current slot in aiCur[] and aiColumn[] */
  unsigned char nEquiv;      /* Number of entries in aiCur[] and aiColumn[] */
  int aiCur[11];             /* Cursors in the equivalence class */
  i16 aiColumn[11];          /* Corresponding column number in the eq-class */
};

/*
** An instance of the following structure holds all information about a
** WHERE clause.  Mostly this is a container for one or more WhereTerms.
**
** Explanation of pOuter:  For a WHERE clause of the form
**
**           a AND ((b AND c) OR (d AND e)) AND f
**
** There are separate WhereClause objects for the whole clause and for
** the subclauses "(b AND c)" and "(d AND e)".  The pOuter field of the
** subclauses points to the WhereClause object for the whole clause.
*/
struct WhereClause {
  WhereInfo *pWInfo;       /* WHERE clause processing context */
  WhereClause *pOuter;     /* Outer conjunction */
  u8 op;                   /* Split operator.  TK_AND or TK_OR */
  u8 hasOr;                /* True if any a[].eOperator is WO_OR */
  int nTerm;               /* Number of terms */
  int nSlot;               /* Number of entries in a[] */
  int nBase;               /* Number of terms through the last non-Virtual */
  WhereTerm *a;            /* Each a[] describes a term of the WHERE clause */
#if defined(SQLITE_SMALL_STACK)
  WhereTerm aStatic[1];    /* Initial static space for a[] */
#else
  WhereTerm aStatic[8];    /* Initial static space for a[] */
#endif
};

/*
** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to
** a dynamically allocated instance of the following structure.
*/
struct WhereOrInfo {
  WhereClause wc;          /* Decomposition into subterms */
  Bitmask indexable;       /* Bitmask of all indexable tables in the clause */
};

/*
** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to
** a dynamically allocated instance of the following structure.
*/
struct WhereAndInfo {
  WhereClause wc;          /* The subexpression broken out */
};

/*
** An instance of the following structure keeps track of a mapping
** between VDBE cursor numbers and bits of the bitmasks in WhereTerm.
**
** The VDBE cursor numbers are small integers contained in
** SrcItem.iCursor and Expr.iTable fields.  For any given WHERE
** clause, the cursor numbers might not begin with 0 and they might
** contain gaps in the numbering sequence.  But we want to make maximum
** use of the bits in our bitmasks.  This structure provides a mapping
** from the sparse cursor numbers into consecutive integers beginning
** with 0.
**
** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask
** corresponds VDBE cursor number B.  The A-th bit of a bitmask is 1<<A.
**
** For example, if the WHERE clause expression used these VDBE
** cursors:  4, 5, 8, 29, 57, 73.  Then the  WhereMaskSet structure
** would map those cursor numbers into bits 0 through 5.
**
** Note that the mapping is not necessarily ordered.  In the example
** above, the mapping might go like this:  4->3, 5->1, 8->2, 29->0,
** 57->5, 73->4.  Or one of 719 other combinations might be used. It
** does not really matter.  What is important is that sparse cursor
** numbers all get mapped into bit numbers that begin with 0 and contain
** no gaps.
*/
struct WhereMaskSet {
  int bVarSelect;               /* Used by sqlite3WhereExprUsage() */
  int n;                        /* Number of assigned cursor values */
  int ix[BMS];                  /* Cursor assigned to each bit */
};

/*
** This object is a convenience wrapper holding all information needed
** to construct WhereLoop objects for a particular query.
*/
struct WhereLoopBuilder {
  WhereInfo *pWInfo;        /* Information about this WHERE */
  WhereClause *pWC;         /* WHERE clause terms */
  WhereLoop *pNew;          /* Template WhereLoop */
  WhereOrSet *pOrSet;       /* Record best loops here, if not NULL */
#ifdef SQLITE_ENABLE_STAT4
  UnpackedRecord *pRec;     /* Probe for stat4 (if required) */
  int nRecValid;            /* Number of valid fields currently in pRec */
#endif
  unsigned char bldFlags1;  /* First set of SQLITE_BLDF_* flags */
  unsigned char bldFlags2;  /* Second set of SQLITE_BLDF_* flags */
  unsigned int iPlanLimit;  /* Search limiter */
};

/* Allowed values for WhereLoopBuider.bldFlags */
#define SQLITE_BLDF1_INDEXED  0x0001   /* An index is used */
#define SQLITE_BLDF1_UNIQUE   0x0002   /* All keys of a UNIQUE index used */

#define SQLITE_BLDF2_2NDPASS  0x0004   /* Second builder pass needed */

/* The WhereLoopBuilder.iPlanLimit is used to limit the number of
** index+constraint combinations the query planner will consider for a
** particular query.  If this parameter is unlimited, then certain
** pathological queries can spend excess time in the sqlite3WhereBegin()
** routine.  The limit is high enough that is should not impact real-world
** queries.
**
** SQLITE_QUERY_PLANNER_LIMIT is the baseline limit.  The limit is
** increased by SQLITE_QUERY_PLANNER_LIMIT_INCR before each term of the FROM
** clause is processed, so that every table in a join is guaranteed to be
** able to propose a some index+constraint combinations even if the initial
** baseline limit was exhausted by prior tables of the join.
*/
#ifndef SQLITE_QUERY_PLANNER_LIMIT
# define SQLITE_QUERY_PLANNER_LIMIT 20000
#endif
#ifndef SQLITE_QUERY_PLANNER_LIMIT_INCR
# define SQLITE_QUERY_PLANNER_LIMIT_INCR 1000
#endif

/*
** The WHERE clause processing routine has two halves.  The
** first part does the start of the WHERE loop and the second
** half does the tail of the WHERE loop.  An instance of
** this structure is returned by the first half and passed
** into the second half to give some continuity.
**
** An instance of this object holds the complete state of the query
** planner.
*/
struct WhereInfo {
  Parse *pParse;            /* Parsing and code generating context */
  SrcList *pTabList;        /* List of tables in the join */
  ExprList *pOrderBy;       /* The ORDER BY clause or NULL */
  ExprList *pResultSet;     /* Result set of the query */
#if WHERETRACE_ENABLED
  Expr *pWhere;             /* The complete WHERE clause */
#endif
  Select *pSelect;          /* The entire SELECT statement containing WHERE */
  int aiCurOnePass[2];      /* OP_OpenWrite cursors for the ONEPASS opt */
  int iContinue;            /* Jump here to continue with next record */
  int iBreak;               /* Jump here to break out of the loop */
  int savedNQueryLoop;      /* pParse->nQueryLoop outside the WHERE loop */
  u16 wctrlFlags;           /* Flags originally passed to sqlite3WhereBegin() */
  LogEst iLimit;            /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */
  u8 nLevel;                /* Number of nested loop */
  i8 nOBSat;                /* Number of ORDER BY terms satisfied by indices */
  u8 eOnePass;              /* ONEPASS_OFF, or _SINGLE, or _MULTI */
  u8 eDistinct;             /* One of the WHERE_DISTINCT_* values */
  unsigned bDeferredSeek :1;   /* Uses OP_DeferredSeek */
  unsigned untestedTerms :1;   /* Not all WHERE terms resolved by outer loop */
  unsigned bOrderedInnerLoop:1;/* True if only the inner-most loop is ordered */
  unsigned sorted        :1;   /* True if really sorted (not just grouped) */
  unsigned bStarDone     :1;   /* True if check for star-query is complete */
  unsigned bStarUsed     :1;   /* True if star-query heuristic is used */
  LogEst nRowOut;           /* Estimated number of output rows */
#ifdef WHERETRACE_ENABLED
  LogEst rTotalCost;        /* Total cost of the solution */
#endif
  int iTop;                 /* The very beginning of the WHERE loop */
  int iEndWhere;            /* End of the WHERE clause itself */
  WhereLoop *pLoops;        /* List of all WhereLoop objects */
  WhereMemBlock *pMemToFree;/* Memory to free when this object destroyed */
  Bitmask revMask;          /* Mask of ORDER BY terms that need reversing */
  WhereClause sWC;          /* Decomposition of the WHERE clause */
  WhereMaskSet sMaskSet;    /* Map cursor numbers to bitmasks */
  WhereLevel a[FLEXARRAY];  /* Information about each nest loop in WHERE */
};

/*
** The size (in bytes) of a WhereInfo object that holds N WhereLevels.
*/
#define SZ_WHEREINFO(N) ROUND8(offsetof(WhereInfo,a)+(N)*sizeof(WhereLevel))

/*
** Private interfaces - callable only by other where.c routines.
**
** where.c:
*/
SQLITE_PRIVATE Bitmask sqlite3WhereGetMask(WhereMaskSet*,int);
#ifdef WHERETRACE_ENABLED
SQLITE_PRIVATE void sqlite3WhereClausePrint(WhereClause *pWC);
SQLITE_PRIVATE void sqlite3WhereTermPrint(WhereTerm *pTerm, int iTerm);
SQLITE_PRIVATE void sqlite3WhereLoopPrint(const WhereLoop *p, const WhereClause *pWC);
#endif
SQLITE_PRIVATE WhereTerm *sqlite3WhereFindTerm(
  WhereClause *pWC,     /* The WHERE clause to be searched */
  int iCur,             /* Cursor number of LHS */
  int iColumn,          /* Column number of LHS */
  Bitmask notReady,     /* RHS must not overlap with this mask */
  u32 op,               /* Mask of WO_xx values describing operator */
  Index *pIdx           /* Must be compatible with this index, if not NULL */
);
SQLITE_PRIVATE void *sqlite3WhereMalloc(WhereInfo *pWInfo, u64 nByte);
SQLITE_PRIVATE void *sqlite3WhereRealloc(WhereInfo *pWInfo, void *pOld, u64 nByte);

/* wherecode.c: */
#ifndef SQLITE_OMIT_EXPLAIN
SQLITE_PRIVATE int sqlite3WhereExplainOneScan(
  Parse *pParse,                  /* Parse context */
  SrcList *pTabList,              /* Table list this loop refers to */
  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
  u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
);
SQLITE_PRIVATE int sqlite3WhereExplainBloomFilter(
  const Parse *pParse,            /* Parse context */
  const WhereInfo *pWInfo,        /* WHERE clause */
  const WhereLevel *pLevel        /* Bloom filter on this level */
);
SQLITE_PRIVATE void sqlite3WhereAddExplainText(
  Parse *pParse,                  /* Parse context */
  int addr,
  SrcList *pTabList,              /* Table list this loop refers to */
  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
  u16 wctrlFlags                  /* Flags passed to sqlite3WhereBegin() */
);
#else
# define sqlite3WhereExplainOneScan(u,v,w,x) 0
# define sqlite3WhereExplainBloomFilter(u,v,w) 0
# define  sqlite3WhereAddExplainText(u,v,w,x,y)
#endif /* SQLITE_OMIT_EXPLAIN */
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
SQLITE_PRIVATE void sqlite3WhereAddScanStatus(
  Vdbe *v,                        /* Vdbe to add scanstatus entry to */
  SrcList *pSrclist,              /* FROM clause pLvl reads data from */
  WhereLevel *pLvl,               /* Level to add scanstatus() entry for */

sqlite3.c  view on Meta::CPAN

        }
      }
    }
  }
  *pzAff = zAff;
  return regBase;
}

#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
/*
** If the most recently coded instruction is a constant range constraint
** (a string literal) that originated from the LIKE optimization, then
** set P3 and P5 on the OP_String opcode so that the string will be cast
** to a BLOB at appropriate times.
**
** The LIKE optimization trys to evaluate "x LIKE 'abc%'" as a range
** expression: "x>='ABC' AND x<'abd'".  But this requires that the range
** scan loop run twice, once for strings and a second time for BLOBs.
** The OP_String opcodes on the second pass convert the upper and lower
** bound string constants to blobs.  This routine makes the necessary changes
** to the OP_String opcodes for that to happen.
**
** Except, of course, if SQLITE_LIKE_DOESNT_MATCH_BLOBS is defined, then
** only the one pass through the string space is required, so this routine
** becomes a no-op.
*/
static void whereLikeOptimizationStringFixup(
  Vdbe *v,                /* prepared statement under construction */
  WhereLevel *pLevel,     /* The loop that contains the LIKE operator */
  WhereTerm *pTerm        /* The upper or lower bound just coded */
){
  if( pTerm->wtFlags & TERM_LIKEOPT ){
    VdbeOp *pOp;
    assert( pLevel->iLikeRepCntr>0 );
    pOp = sqlite3VdbeGetLastOp(v);
    assert( pOp!=0 );
    assert( pOp->opcode==OP_String8
            || pTerm->pWC->pWInfo->pParse->db->mallocFailed );
    pOp->p3 = (int)(pLevel->iLikeRepCntr>>1);  /* Register holding counter */
    pOp->p5 = (u8)(pLevel->iLikeRepCntr&1);    /* ASC or DESC */
  }
}
#else
# define whereLikeOptimizationStringFixup(A,B,C)
#endif

#ifdef SQLITE_ENABLE_CURSOR_HINTS
/*
** Information is passed from codeCursorHint() down to individual nodes of
** the expression tree (by sqlite3WalkExpr()) using an instance of this
** structure.
*/
struct CCurHint {
  int iTabCur;    /* Cursor for the main table */
  int iIdxCur;    /* Cursor for the index, if pIdx!=0.  Unused otherwise */
  Index *pIdx;    /* The index used to access the table */
};

/*
** This function is called for every node of an expression that is a candidate
** for a cursor hint on an index cursor.  For TK_COLUMN nodes that reference
** the table CCurHint.iTabCur, verify that the same column can be
** accessed through the index.  If it cannot, then set pWalker->eCode to 1.
*/
static int codeCursorHintCheckExpr(Walker *pWalker, Expr *pExpr){
  struct CCurHint *pHint = pWalker->u.pCCurHint;
  assert( pHint->pIdx!=0 );
  if( pExpr->op==TK_COLUMN
   && pExpr->iTable==pHint->iTabCur
   && sqlite3TableColumnToIndex(pHint->pIdx, pExpr->iColumn)<0
  ){
    pWalker->eCode = 1;
  }
  return WRC_Continue;
}

/*
** Test whether or not expression pExpr, which was part of a WHERE clause,
** should be included in the cursor-hint for a table that is on the rhs
** of a LEFT JOIN. Set Walker.eCode to non-zero before returning if the
** expression is not suitable.
**
** An expression is unsuitable if it might evaluate to non NULL even if
** a TK_COLUMN node that does affect the value of the expression is set
** to NULL. For example:
**
**   col IS NULL
**   col IS NOT NULL
**   coalesce(col, 1)
**   CASE WHEN col THEN 0 ELSE 1 END
*/
static int codeCursorHintIsOrFunction(Walker *pWalker, Expr *pExpr){
  if( pExpr->op==TK_IS
   || pExpr->op==TK_ISNULL || pExpr->op==TK_ISNOT
   || pExpr->op==TK_NOTNULL || pExpr->op==TK_CASE
  ){
    pWalker->eCode = 1;
  }else if( pExpr->op==TK_FUNCTION ){
    int d1;
    char d2[4];
    if( 0==sqlite3IsLikeFunction(pWalker->pParse->db, pExpr, &d1, d2) ){
      pWalker->eCode = 1;
    }
  }

  return WRC_Continue;
}


/*
** This function is called on every node of an expression tree used as an
** argument to the OP_CursorHint instruction. If the node is a TK_COLUMN
** that accesses any table other than the one identified by
** CCurHint.iTabCur, then do the following:
**
**   1) allocate a register and code an OP_Column instruction to read
**      the specified column into the new register, and
**
**   2) transform the expression node to a TK_REGISTER node that reads
**      from the newly populated register.
**
** Also, if the node is a TK_COLUMN that does access the table identified
** by pCCurHint.iTabCur, and an index is being used (which we will
** know because CCurHint.pIdx!=0) then transform the TK_COLUMN into
** an access of the index rather than the original table.
*/
static int codeCursorHintFixExpr(Walker *pWalker, Expr *pExpr){
  int rc = WRC_Continue;
  int reg;
  struct CCurHint *pHint = pWalker->u.pCCurHint;
  if( pExpr->op==TK_COLUMN ){
    if( pExpr->iTable!=pHint->iTabCur ){
      reg = ++pWalker->pParse->nMem;   /* Register for column value */
      reg = sqlite3ExprCodeTarget(pWalker->pParse, pExpr, reg);
      pExpr->op = TK_REGISTER;
      pExpr->iTable = reg;
    }else if( pHint->pIdx!=0 ){
      pExpr->iTable = pHint->iIdxCur;
      pExpr->iColumn = sqlite3TableColumnToIndex(pHint->pIdx, pExpr->iColumn);
      assert( pExpr->iColumn>=0 );
    }
  }else if( pExpr->pAggInfo ){
    rc = WRC_Prune;
    reg = ++pWalker->pParse->nMem;   /* Register for column value */
    reg = sqlite3ExprCodeTarget(pWalker->pParse, pExpr, reg);
    pExpr->op = TK_REGISTER;
    pExpr->iTable = reg;
  }else if( pExpr->op==TK_TRUEFALSE ){
    /* Do not walk disabled expressions.  tag-20230504-1 */
    return WRC_Prune;
  }
  return rc;
}

/*
** Insert an OP_CursorHint instruction if it is appropriate to do so.
*/
static void codeCursorHint(
  SrcItem *pTabItem,  /* FROM clause item */
  WhereInfo *pWInfo,    /* The where clause */
  WhereLevel *pLevel,   /* Which loop to provide hints for */
  WhereTerm *pEndRange  /* Hint this end-of-scan boundary term if not NULL */
){
  Parse *pParse = pWInfo->pParse;
  sqlite3 *db = pParse->db;
  Vdbe *v = pParse->pVdbe;
  Expr *pExpr = 0;
  WhereLoop *pLoop = pLevel->pWLoop;
  int iCur;
  WhereClause *pWC;
  WhereTerm *pTerm;
  int i, j;
  struct CCurHint sHint;
  Walker sWalker;

  if( OptimizationDisabled(db, SQLITE_CursorHints) ) return;
  iCur = pLevel->iTabCur;
  assert( iCur==pWInfo->pTabList->a[pLevel->iFrom].iCursor );
  sHint.iTabCur = iCur;
  sHint.iIdxCur = pLevel->iIdxCur;
  sHint.pIdx = pLoop->u.btree.pIndex;
  memset(&sWalker, 0, sizeof(sWalker));
  sWalker.pParse = pParse;
  sWalker.u.pCCurHint = &sHint;
  pWC = &pWInfo->sWC;
  for(i=0; i<pWC->nBase; i++){
    pTerm = &pWC->a[i];
    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
    if( pTerm->prereqAll & pLevel->notReady ) continue;

    /* Any terms specified as part of the ON(...) clause for any LEFT
    ** JOIN for which the current table is not the rhs are omitted
    ** from the cursor-hint.
    **
    ** If this table is the rhs of a LEFT JOIN, "IS" or "IS NULL" terms
    ** that were specified as part of the WHERE clause must be excluded.
    ** This is to address the following:
    **
    **   SELECT ... t1 LEFT JOIN t2 ON (t1.a=t2.b) WHERE t2.c IS NULL;
    **
    ** Say there is a single row in t2 that matches (t1.a=t2.b), but its
    ** t2.c values is not NULL. If the (t2.c IS NULL) constraint is
    ** pushed down to the cursor, this row is filtered out, causing
    ** SQLite to synthesize a row of NULL values. Which does match the
    ** WHERE clause, and so the query returns a row. Which is incorrect.
    **
    ** For the same reason, WHERE terms such as:
    **
    **   WHERE 1 = (t2.c IS NULL)
    **
    ** are also excluded. See codeCursorHintIsOrFunction() for details.
    */
    if( pTabItem->fg.jointype & JT_LEFT ){
      Expr *pExpr = pTerm->pExpr;
      if( !ExprHasProperty(pExpr, EP_OuterON)
       || pExpr->w.iJoin!=pTabItem->iCursor
      ){
        sWalker.eCode = 0;
        sWalker.xExprCallback = codeCursorHintIsOrFunction;
        sqlite3WalkExpr(&sWalker, pTerm->pExpr);
        if( sWalker.eCode ) continue;
      }
    }else{
      if( ExprHasProperty(pTerm->pExpr, EP_OuterON) ) continue;
    }

    /* All terms in pWLoop->aLTerm[] except pEndRange are used to initialize
    ** the cursor.  These terms are not needed as hints for a pure range
    ** scan (that has no == terms) so omit them. */
    if( pLoop->u.btree.nEq==0 && pTerm!=pEndRange ){
      for(j=0; j<pLoop->nLTerm && pLoop->aLTerm[j]!=pTerm; j++){}
      if( j<pLoop->nLTerm ) continue;
    }

    /* No subqueries or non-deterministic functions allowed */
    if( sqlite3ExprContainsSubquery(pTerm->pExpr) ) continue;

    /* For an index scan, make sure referenced columns are actually in
    ** the index. */
    if( sHint.pIdx!=0 ){
      sWalker.eCode = 0;
      sWalker.xExprCallback = codeCursorHintCheckExpr;
      sqlite3WalkExpr(&sWalker, pTerm->pExpr);
      if( sWalker.eCode ) continue;
    }

    /* If we survive all prior tests, that means this term is worth hinting */
    pExpr = sqlite3ExprAnd(pParse, pExpr, sqlite3ExprDup(db, pTerm->pExpr, 0));
  }
  if( pExpr!=0 ){
    sWalker.xExprCallback = codeCursorHintFixExpr;
    if( pParse->nErr==0 ) sqlite3WalkExpr(&sWalker, pExpr);
    sqlite3VdbeAddOp4(v, OP_CursorHint,
                      (sHint.pIdx ? sHint.iIdxCur : sHint.iTabCur), 0, 0,
                      (const char*)pExpr, P4_EXPR);
  }
}
#else
# define codeCursorHint(A,B,C,D)  /* No-op */
#endif /* SQLITE_ENABLE_CURSOR_HINTS */

/*
** Cursor iCur is open on an intkey b-tree (a table). Register iRowid contains
** a rowid value just read from cursor iIdxCur, open on index pIdx. This
** function generates code to do a deferred seek of cursor iCur to the
** rowid stored in register iRowid.
**
** Normally, this is just:
**
**   OP_DeferredSeek $iCur $iRowid
**
** Which causes a seek on $iCur to the row with rowid $iRowid.
**
** However, if the scan currently being coded is a branch of an OR-loop and
** the statement currently being coded is a SELECT, then additional information
** is added that might allow OP_Column to omit the seek and instead do its
** lookup on the index, thus avoiding an expensive seek operation.  To
** enable this optimization, the P3 of OP_DeferredSeek is set to iIdxCur
** and P4 is set to an array of integers containing one entry for each column
** in the table.  For each table column, if the column is the i'th
** column of the index, then the corresponding array entry is set to (i+1).
** If the column does not appear in the index at all, the array entry is set
** to 0.  The OP_Column opcode can check this array to see if the column it
** wants is in the index and if it is, it will substitute the index cursor
** and column number and continue with those new values, rather than seeking
** the table cursor.
*/
static void codeDeferredSeek(
  WhereInfo *pWInfo,              /* Where clause context */
  Index *pIdx,                    /* Index scan is using */
  int iCur,                       /* Cursor for IPK b-tree */
  int iIdxCur                     /* Index cursor */
){
  Parse *pParse = pWInfo->pParse; /* Parse context */
  Vdbe *v = pParse->pVdbe;        /* Vdbe to generate code within */

  assert( iIdxCur>0 );
  assert( pIdx->aiColumn[pIdx->nColumn-1]==-1 );

  pWInfo->bDeferredSeek = 1;
  sqlite3VdbeAddOp3(v, OP_DeferredSeek, iIdxCur, 0, iCur);
  if( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))
   && DbMaskAllZero(sqlite3ParseToplevel(pParse)->writeMask)
  ){
    int i;
    Table *pTab = pIdx->pTable;
    u32 *ai = (u32*)sqlite3DbMallocZero(pParse->db, sizeof(u32)*(pTab->nCol+1));
    if( ai ){
      ai[0] = pTab->nCol;
      for(i=0; i<pIdx->nColumn-1; i++){
        int x1, x2;
        assert( pIdx->aiColumn[i]<pTab->nCol );
        x1 = pIdx->aiColumn[i];
        x2 = sqlite3TableColumnToStorage(pTab, x1);
        testcase( x1!=x2 );
        if( x1>=0 ) ai[x2+1] = i+1;
      }
      sqlite3VdbeChangeP4(v, -1, (char*)ai, P4_INTARRAY);
    }
  }
}

/*
** If the expression passed as the second argument is a vector, generate
** code to write the first nReg elements of the vector into an array
** of registers starting with iReg.
**
** If the expression is not a vector, then nReg must be passed 1. In
** this case, generate code to evaluate the expression and leave the
** result in register iReg.
*/
static void codeExprOrVector(Parse *pParse, Expr *p, int iReg, int nReg){
  assert( nReg>0 );
  if( p && sqlite3ExprIsVector(p) ){
#ifndef SQLITE_OMIT_SUBQUERY
    if( ExprUseXSelect(p) ){
      Vdbe *v = pParse->pVdbe;
      int iSelect;
      assert( p->op==TK_SELECT );
      iSelect = sqlite3CodeSubselect(pParse, p);
      sqlite3VdbeAddOp3(v, OP_Copy, iSelect, iReg, nReg-1);
    }else
#endif
    {
      int i;
      const ExprList *pList;
      assert( ExprUseXList(p) );
      pList = p->x.pList;
      assert( nReg<=pList->nExpr );
      for(i=0; i<nReg; i++){
        sqlite3ExprCode(pParse, pList->a[i].pExpr, iReg+i);
      }

sqlite3.c  view on Meta::CPAN

      regRowid = sqlite3GetTempReg(pParse);
      regRowid = codeEqualityTerm(pParse, pTerm, pLevel, 0, 0, regRowid);
      sqlite3VdbeAddOp2(pParse->pVdbe, OP_MustBeInt, regRowid, addrNxt);
      VdbeCoverage(pParse->pVdbe);
      sqlite3VdbeAddOp4Int(pParse->pVdbe, OP_Filter, pLevel->regFilter,
                           addrNxt, regRowid, 1);
      VdbeCoverage(pParse->pVdbe);
    }else{
      u16 nEq = pLoop->u.btree.nEq;
      int r1;
      char *zStartAff;

      assert( pLoop->wsFlags & WHERE_INDEXED );
      assert( (pLoop->wsFlags & WHERE_COLUMN_IN)==0 );
      r1 = codeAllEqualityTerms(pParse,pLevel,0,0,&zStartAff);
      codeApplyAffinity(pParse, r1, nEq, zStartAff);
      sqlite3DbFree(pParse->db, zStartAff);
      sqlite3VdbeAddOp4Int(pParse->pVdbe, OP_Filter, pLevel->regFilter,
                           addrNxt, r1, nEq);
      VdbeCoverage(pParse->pVdbe);
    }
    pLevel->regFilter = 0;
    pLevel->addrBrk = saved_addrBrk;
  }
}

/*
** Loop pLoop is a WHERE_INDEXED level that uses at least one IN(...)
** operator. Return true if level pLoop is guaranteed to visit only one
** row for each key generated for the index.
*/
static int whereLoopIsOneRow(WhereLoop *pLoop){
  if( pLoop->u.btree.pIndex->onError
   && pLoop->nSkip==0
   && pLoop->u.btree.nEq==pLoop->u.btree.pIndex->nKeyCol
  ){
    int ii;
    for(ii=0; ii<pLoop->u.btree.nEq; ii++){
      if( pLoop->aLTerm[ii]->eOperator & (WO_IS|WO_ISNULL) ){
        return 0;
      }
    }
    return 1;
  }
  return 0;
}

/*
** Generate code for the start of the iLevel-th loop in the WHERE clause
** implementation described by pWInfo.
*/
SQLITE_PRIVATE Bitmask sqlite3WhereCodeOneLoopStart(
  Parse *pParse,       /* Parsing context */
  Vdbe *v,             /* Prepared statement under construction */
  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
  int iLevel,          /* Which level of pWInfo->a[] should be coded */
  WhereLevel *pLevel,  /* The current level pointer */
  Bitmask notReady     /* Which tables are currently available */
){
  int j, k;            /* Loop counters */
  int iCur;            /* The VDBE cursor for the table */
  int addrNxt;         /* Where to jump to continue with the next IN case */
  int bRev;            /* True if we need to scan in reverse order */
  WhereLoop *pLoop;    /* The WhereLoop object being coded */
  WhereClause *pWC;    /* Decomposition of the entire WHERE clause */
  WhereTerm *pTerm;               /* A WHERE clause term */
  sqlite3 *db;                    /* Database connection */
  SrcItem *pTabItem;              /* FROM clause term being coded */
  int addrBrk;                    /* Jump here to break out of the loop */
  int addrCont;                   /* Jump here to continue with next cycle */
  int iRowidReg = 0;        /* Rowid is stored in this register, if not zero */
  int iReleaseReg = 0;      /* Temp register to free before returning */
  Index *pIdx = 0;          /* Index used by loop (if any) */
  int iLoop;                /* Iteration of constraint generator loop */

  pWC = &pWInfo->sWC;
  db = pParse->db;
  pLoop = pLevel->pWLoop;
  pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
  iCur = pTabItem->iCursor;
  pLevel->notReady = notReady & ~sqlite3WhereGetMask(&pWInfo->sMaskSet, iCur);
  bRev = (pWInfo->revMask>>iLevel)&1;
  VdbeModuleComment((v, "Begin WHERE-loop%d: %s",
                     iLevel, pTabItem->pSTab->zName));
#if WHERETRACE_ENABLED /* 0x4001 */
  if( sqlite3WhereTrace & 0x1 ){
    sqlite3DebugPrintf("Coding level %d of %d:  notReady=%llx  iFrom=%d\n",
       iLevel, pWInfo->nLevel, (u64)notReady, pLevel->iFrom);
    if( sqlite3WhereTrace & 0x1000 ){
      sqlite3WhereLoopPrint(pLoop, pWC);
    }
  }
  if( (sqlite3WhereTrace & 0x4001)==0x4001 ){
    if( iLevel==0 ){
      sqlite3DebugPrintf("WHERE clause being coded:\n");
      sqlite3TreeViewExpr(0, pWInfo->pWhere, 0);
    }
    sqlite3DebugPrintf("All WHERE-clause terms before coding:\n");
    sqlite3WhereClausePrint(pWC);
  }
#endif

  /* Create labels for the "break" and "continue" instructions
  ** for the current loop.  Jump to addrBrk to break out of a loop.
  ** Jump to cont to go immediately to the next iteration of the
  ** loop.
  **
  ** When there is an IN operator, we also have a "addrNxt" label that
  ** means to continue with the next IN value combination.  When
  ** there are no IN operators in the constraints, the "addrNxt" label
  ** is the same as "addrBrk".
  */
  addrBrk = pLevel->addrNxt = pLevel->addrBrk;
  addrCont = pLevel->addrCont = sqlite3VdbeMakeLabel(pParse);

  /* If this is the right table of a LEFT OUTER JOIN, allocate and
  ** initialize a memory cell that records if this table matches any
  ** row of the left table of the join.
  */
  assert( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))
       || pLevel->iFrom>0 || (pTabItem[0].fg.jointype & JT_LEFT)==0

sqlite3.c  view on Meta::CPAN

      sqlite3VdbeChangeP5(v, SQLITE_AFF_NUMERIC | SQLITE_JUMPIFNULL);
    }
  }else if( pLoop->wsFlags & WHERE_INDEXED ){
    /* Case 4: Search using an index.
    **
    ** The WHERE clause may contain zero or more equality
    ** terms ("==" or "IN" or "IS" operators) that refer to the N
    ** left-most columns of the index. It may also contain
    ** inequality constraints (>, <, >= or <=) on the indexed
    ** column that immediately follows the N equalities. Only
    ** the right-most column can be an inequality - the rest must
    ** use the "==", "IN", or "IS" operators. For example, if the
    ** index is on (x,y,z), then the following clauses are all
    ** optimized:
    **
    **    x=5
    **    x=5 AND y=10
    **    x=5 AND y<10
    **    x=5 AND y>5 AND y<10
    **    x=5 AND y=5 AND z<=10
    **
    ** The z<10 term of the following cannot be used, only
    ** the x=5 term:
    **
    **    x=5 AND z<10
    **
    ** N may be zero if there are inequality constraints.
    ** If there are no inequality constraints, then N is at
    ** least one.
    **
    ** This case is also used when there are no WHERE clause
    ** constraints but an index is selected anyway, in order
    ** to force the output order to conform to an ORDER BY.
    */
    static const u8 aStartOp[] = {
      0,
      0,
      OP_Rewind,           /* 2: (!start_constraints && startEq &&  !bRev) */
      OP_Last,             /* 3: (!start_constraints && startEq &&   bRev) */
      OP_SeekGT,           /* 4: (start_constraints  && !startEq && !bRev) */
      OP_SeekLT,           /* 5: (start_constraints  && !startEq &&  bRev) */
      OP_SeekGE,           /* 6: (start_constraints  &&  startEq && !bRev) */
      OP_SeekLE            /* 7: (start_constraints  &&  startEq &&  bRev) */
    };
    static const u8 aEndOp[] = {
      OP_IdxGE,            /* 0: (end_constraints && !bRev && !endEq) */
      OP_IdxGT,            /* 1: (end_constraints && !bRev &&  endEq) */
      OP_IdxLE,            /* 2: (end_constraints &&  bRev && !endEq) */
      OP_IdxLT,            /* 3: (end_constraints &&  bRev &&  endEq) */
    };
    u16 nEq = pLoop->u.btree.nEq;     /* Number of == or IN terms */
    u16 nBtm = pLoop->u.btree.nBtm;   /* Length of BTM vector */
    u16 nTop = pLoop->u.btree.nTop;   /* Length of TOP vector */
    int regBase;                 /* Base register holding constraint values */
    WhereTerm *pRangeStart = 0;  /* Inequality constraint at range start */
    WhereTerm *pRangeEnd = 0;    /* Inequality constraint at range end */
    int startEq;                 /* True if range start uses ==, >= or <= */
    int endEq;                   /* True if range end uses ==, >= or <= */
    int start_constraints;       /* Start of range is constrained */
    int nConstraint;             /* Number of constraint terms */
    int iIdxCur;                 /* The VDBE cursor for the index */
    int nExtraReg = 0;           /* Number of extra registers needed */
    int op;                      /* Instruction opcode */
    char *zStartAff;             /* Affinity for start of range constraint */
    char *zEndAff = 0;           /* Affinity for end of range constraint */
    u8 bSeekPastNull = 0;        /* True to seek past initial nulls */
    u8 bStopAtNull = 0;          /* Add condition to terminate at NULLs */
    int omitTable;               /* True if we use the index only */
    int regBignull = 0;          /* big-null flag register */
    int addrSeekScan = 0;        /* Opcode of the OP_SeekScan, if any */

    pIdx = pLoop->u.btree.pIndex;
    iIdxCur = pLevel->iIdxCur;
    assert( nEq>=pLoop->nSkip );

    /* Find any inequality constraint terms for the start and end
    ** of the range.
    */
    j = nEq;
    if( pLoop->wsFlags & WHERE_BTM_LIMIT ){
      pRangeStart = pLoop->aLTerm[j++];
      nExtraReg = MAX(nExtraReg, pLoop->u.btree.nBtm);
      /* Like optimization range constraints always occur in pairs */
      assert( (pRangeStart->wtFlags & TERM_LIKEOPT)==0 ||
              (pLoop->wsFlags & WHERE_TOP_LIMIT)!=0 );
    }
    if( pLoop->wsFlags & WHERE_TOP_LIMIT ){
      pRangeEnd = pLoop->aLTerm[j++];
      nExtraReg = MAX(nExtraReg, pLoop->u.btree.nTop);
#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
      if( (pRangeEnd->wtFlags & TERM_LIKEOPT)!=0 ){
        assert( pRangeStart!=0 );                     /* LIKE opt constraints */
        assert( pRangeStart->wtFlags & TERM_LIKEOPT );   /* occur in pairs */
        pLevel->iLikeRepCntr = (u32)++pParse->nMem;
        sqlite3VdbeAddOp2(v, OP_Integer, 1, (int)pLevel->iLikeRepCntr);
        VdbeComment((v, "LIKE loop counter"));
        pLevel->addrLikeRep = sqlite3VdbeCurrentAddr(v);
        /* iLikeRepCntr actually stores 2x the counter register number.  The
        ** bottom bit indicates whether the search order is ASC or DESC. */
        testcase( bRev );
        testcase( pIdx->aSortOrder[nEq]==SQLITE_SO_DESC );
        assert( (bRev & ~1)==0 );
        pLevel->iLikeRepCntr <<=1;
        pLevel->iLikeRepCntr |= bRev ^ (pIdx->aSortOrder[nEq]==SQLITE_SO_DESC);
      }
#endif
      if( pRangeStart==0 ){
        j = pIdx->aiColumn[nEq];
        if( (j>=0 && pIdx->pTable->aCol[j].notNull==0) || j==XN_EXPR ){
          bSeekPastNull = 1;
        }
      }
    }
    assert( pRangeEnd==0 || (pRangeEnd->wtFlags & TERM_VNULL)==0 );

    /* If the WHERE_BIGNULL_SORT flag is set, then index column nEq uses
    ** a non-default "big-null" sort (either ASC NULLS LAST or DESC NULLS
    ** FIRST). In both cases separate ordered scans are made of those
    ** index entries for which the column is null and for those for which
    ** it is not. For an ASC sort, the non-NULL entries are scanned first.
    ** For DESC, NULL entries are scanned first.
    */
    if( (pLoop->wsFlags & (WHERE_TOP_LIMIT|WHERE_BTM_LIMIT))==0
     && (pLoop->wsFlags & WHERE_BIGNULL_SORT)!=0
    ){
      assert( bSeekPastNull==0 && nExtraReg==0 && nBtm==0 && nTop==0 );
      assert( pRangeEnd==0 && pRangeStart==0 );
      testcase( pLoop->nSkip>0 );
      nExtraReg = 1;
      bSeekPastNull = 1;
      pLevel->regBignull = regBignull = ++pParse->nMem;
      if( pLevel->iLeftJoin ){
        sqlite3VdbeAddOp2(v, OP_Integer, 0, regBignull);
      }
      pLevel->addrBignull = sqlite3VdbeMakeLabel(pParse);
    }

    /* If we are doing a reverse order scan on an ascending index, or
    ** a forward order scan on a descending index, interchange the
    ** start and end terms (pRangeStart and pRangeEnd).
    */
    if( (nEq<pIdx->nColumn && bRev==(pIdx->aSortOrder[nEq]==SQLITE_SO_ASC)) ){
      SWAP(WhereTerm *, pRangeEnd, pRangeStart);
      SWAP(u8, bSeekPastNull, bStopAtNull);
      SWAP(u8, nBtm, nTop);
    }

    if( iLevel>0 && (pLoop->wsFlags & WHERE_IN_SEEKSCAN)!=0 ){
      /* In case OP_SeekScan is used, ensure that the index cursor does not
      ** point to a valid row for the first iteration of this loop. */
      sqlite3VdbeAddOp1(v, OP_NullRow, iIdxCur);
    }

    /* Generate code to evaluate all constraint terms using == or IN
    ** and store the values of those terms in an array of registers
    ** starting at regBase.
    */
    codeCursorHint(pTabItem, pWInfo, pLevel, pRangeEnd);
    regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff);
    assert( zStartAff==0 || sqlite3Strlen30(zStartAff)>=nEq );
    if( zStartAff && nTop ){
      zEndAff = sqlite3DbStrDup(db, &zStartAff[nEq]);
    }
    addrNxt = (regBignull ? pLevel->addrBignull : pLevel->addrNxt);

    testcase( pRangeStart && (pRangeStart->eOperator & WO_LE)!=0 );
    testcase( pRangeStart && (pRangeStart->eOperator & WO_GE)!=0 );
    testcase( pRangeEnd && (pRangeEnd->eOperator & WO_LE)!=0 );
    testcase( pRangeEnd && (pRangeEnd->eOperator & WO_GE)!=0 );
    startEq = !pRangeStart || pRangeStart->eOperator & (WO_LE|WO_GE);
    endEq =   !pRangeEnd || pRangeEnd->eOperator & (WO_LE|WO_GE);
    start_constraints = pRangeStart || nEq>0;

    /* Seek the index cursor to the start of the range. */
    nConstraint = nEq;
    if( pRangeStart ){
      Expr *pRight = pRangeStart->pExpr->pRight;
      codeExprOrVector(pParse, pRight, regBase+nEq, nBtm);
      whereLikeOptimizationStringFixup(v, pLevel, pRangeStart);
      if( (pRangeStart->wtFlags & TERM_VNULL)==0
       && sqlite3ExprCanBeNull(pRight)
      ){
        sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
        VdbeCoverage(v);
      }
      if( zStartAff ){
        updateRangeAffinityStr(pRight, nBtm, &zStartAff[nEq]);
      }
      nConstraint += nBtm;
      testcase( pRangeStart->wtFlags & TERM_VIRTUAL );
      if( sqlite3ExprIsVector(pRight)==0 ){
        disableTerm(pLevel, pRangeStart);
      }else{
        startEq = 1;
      }
      bSeekPastNull = 0;
    }else if( bSeekPastNull ){
      startEq = 0;
      sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
      start_constraints = 1;
      nConstraint++;
    }else if( regBignull ){
      sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
      start_constraints = 1;
      nConstraint++;
    }
    codeApplyAffinity(pParse, regBase, nConstraint - bSeekPastNull, zStartAff);
    if( pLoop->nSkip>0 && nConstraint==pLoop->nSkip ){
      /* The skip-scan logic inside the call to codeAllEqualityConstraints()
      ** above has already left the cursor sitting on the correct row,
      ** so no further seeking is needed */
    }else{
      if( regBignull ){
        sqlite3VdbeAddOp2(v, OP_Integer, 1, regBignull);
        VdbeComment((v, "NULL-scan pass ctr"));
      }
      if( pLevel->regFilter ){
        sqlite3VdbeAddOp4Int(v, OP_Filter, pLevel->regFilter, addrNxt,
                             regBase, nEq);
        VdbeCoverage(v);
        filterPullDown(pParse, pWInfo, iLevel, addrNxt, notReady);
      }

      op = aStartOp[(start_constraints<<2) + (startEq<<1) + bRev];
      assert( op!=0 );
      if( (pLoop->wsFlags & WHERE_IN_SEEKSCAN)!=0 && op==OP_SeekGE ){
        assert( regBignull==0 );
        /* TUNING:  The OP_SeekScan opcode seeks to reduce the number
        ** of expensive seek operations by replacing a single seek with
        ** 1 or more step operations.  The question is, how many steps
        ** should we try before giving up and going with a seek.  The cost
        ** of a seek is proportional to the logarithm of the of the number
        ** of entries in the tree, so basing the number of steps to try
        ** on the estimated number of rows in the btree seems like a good
        ** guess. */
        addrSeekScan = sqlite3VdbeAddOp1(v, OP_SeekScan,
                                         (pIdx->aiRowLogEst[0]+9)/10);
        if( pRangeStart || pRangeEnd ){
          sqlite3VdbeChangeP5(v, 1);
          sqlite3VdbeChangeP2(v, addrSeekScan, sqlite3VdbeCurrentAddr(v)+1);
          addrSeekScan = 0;
        }
        VdbeCoverage(v);
      }
      sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
      VdbeCoverage(v);
      VdbeCoverageIf(v, op==OP_Rewind);  testcase( op==OP_Rewind );
      VdbeCoverageIf(v, op==OP_Last);    testcase( op==OP_Last );
      VdbeCoverageIf(v, op==OP_SeekGT);  testcase( op==OP_SeekGT );
      VdbeCoverageIf(v, op==OP_SeekGE);  testcase( op==OP_SeekGE );
      VdbeCoverageIf(v, op==OP_SeekLE);  testcase( op==OP_SeekLE );
      VdbeCoverageIf(v, op==OP_SeekLT);  testcase( op==OP_SeekLT );

      assert( bSeekPastNull==0 || bStopAtNull==0 );
      if( regBignull ){
        assert( bSeekPastNull==1 || bStopAtNull==1 );
        assert( bSeekPastNull==!bStopAtNull );
        assert( bStopAtNull==startEq );
        sqlite3VdbeAddOp2(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+2);
        op = aStartOp[(nConstraint>1)*4 + 2 + bRev];
        sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase,
                             nConstraint-startEq);
        VdbeCoverage(v);
        VdbeCoverageIf(v, op==OP_Rewind);  testcase( op==OP_Rewind );
        VdbeCoverageIf(v, op==OP_Last);    testcase( op==OP_Last );
        VdbeCoverageIf(v, op==OP_SeekGE);  testcase( op==OP_SeekGE );
        VdbeCoverageIf(v, op==OP_SeekLE);  testcase( op==OP_SeekLE );
        assert( op==OP_Rewind || op==OP_Last || op==OP_SeekGE || op==OP_SeekLE);
      }
    }

    /* Load the value for the inequality constraint at the end of the
    ** range (if any).
    */
    nConstraint = nEq;
    assert( pLevel->p2==0 );
    if( pRangeEnd ){
      Expr *pRight = pRangeEnd->pExpr->pRight;
      assert( addrSeekScan==0 );
      codeExprOrVector(pParse, pRight, regBase+nEq, nTop);
      whereLikeOptimizationStringFixup(v, pLevel, pRangeEnd);
      if( (pRangeEnd->wtFlags & TERM_VNULL)==0
       && sqlite3ExprCanBeNull(pRight)
      ){
        sqlite3VdbeAddOp2(v, OP_IsNull, regBase+nEq, addrNxt);
        VdbeCoverage(v);
      }
      if( zEndAff ){
        updateRangeAffinityStr(pRight, nTop, zEndAff);
        codeApplyAffinity(pParse, regBase+nEq, nTop, zEndAff);
      }else{
        assert( pParse->db->mallocFailed );
      }
      nConstraint += nTop;
      testcase( pRangeEnd->wtFlags & TERM_VIRTUAL );

      if( sqlite3ExprIsVector(pRight)==0 ){
        disableTerm(pLevel, pRangeEnd);
      }else{
        endEq = 1;
      }
    }else if( bStopAtNull ){
      if( regBignull==0 ){
        sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
        endEq = 0;
      }
      nConstraint++;
    }
    if( zStartAff ) sqlite3DbNNFreeNN(db, zStartAff);
    if( zEndAff ) sqlite3DbNNFreeNN(db, zEndAff);

    /* Top of the loop body */
    pLevel->p2 = sqlite3VdbeCurrentAddr(v);

    /* Check if the index cursor is past the end of the range. */
    if( nConstraint ){
      if( regBignull ){
        /* Except, skip the end-of-range check while doing the NULL-scan */
        sqlite3VdbeAddOp2(v, OP_IfNot, regBignull, sqlite3VdbeCurrentAddr(v)+3);
        VdbeComment((v, "If NULL-scan 2nd pass"));
        VdbeCoverage(v);
      }
      op = aEndOp[bRev*2 + endEq];
      sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
      testcase( op==OP_IdxGT );  VdbeCoverageIf(v, op==OP_IdxGT );
      testcase( op==OP_IdxGE );  VdbeCoverageIf(v, op==OP_IdxGE );
      testcase( op==OP_IdxLT );  VdbeCoverageIf(v, op==OP_IdxLT );
      testcase( op==OP_IdxLE );  VdbeCoverageIf(v, op==OP_IdxLE );
      if( addrSeekScan ) sqlite3VdbeJumpHere(v, addrSeekScan);
    }
    if( regBignull ){
      /* During a NULL-scan, check to see if we have reached the end of
      ** the NULLs */
      assert( bSeekPastNull==!bStopAtNull );
      assert( bSeekPastNull+bStopAtNull==1 );
      assert( nConstraint+bSeekPastNull>0 );
      sqlite3VdbeAddOp2(v, OP_If, regBignull, sqlite3VdbeCurrentAddr(v)+2);
      VdbeComment((v, "If NULL-scan 1st pass"));
      VdbeCoverage(v);
      op = aEndOp[bRev*2 + bSeekPastNull];
      sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase,
                           nConstraint+bSeekPastNull);
      testcase( op==OP_IdxGT );  VdbeCoverageIf(v, op==OP_IdxGT );
      testcase( op==OP_IdxGE );  VdbeCoverageIf(v, op==OP_IdxGE );
      testcase( op==OP_IdxLT );  VdbeCoverageIf(v, op==OP_IdxLT );
      testcase( op==OP_IdxLE );  VdbeCoverageIf(v, op==OP_IdxLE );
    }

    if( (pLoop->wsFlags & WHERE_IN_EARLYOUT)!=0 ){
      sqlite3VdbeAddOp3(v, OP_SeekHit, iIdxCur, nEq, nEq);
    }

    /* Seek the table cursor, if required */
    omitTable = (pLoop->wsFlags & WHERE_IDX_ONLY)!=0
           && (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))==0;
    if( omitTable ){
      /* pIdx is a covering index.  No need to access the main table. */
    }else if( HasRowid(pIdx->pTable) ){
      codeDeferredSeek(pWInfo, pIdx, iCur, iIdxCur);
    }else if( iCur!=iIdxCur ){
      Index *pPk = sqlite3PrimaryKeyIndex(pIdx->pTable);
      iRowidReg = sqlite3GetTempRange(pParse, pPk->nKeyCol);
      for(j=0; j<pPk->nKeyCol; j++){
        k = sqlite3TableColumnToIndex(pIdx, pPk->aiColumn[j]);
        sqlite3VdbeAddOp3(v, OP_Column, iIdxCur, k, iRowidReg+j);
      }
      sqlite3VdbeAddOp4Int(v, OP_NotFound, iCur, addrCont,
                           iRowidReg, pPk->nKeyCol); VdbeCoverage(v);
    }

    if( pLevel->iLeftJoin==0 ){
      /* If a partial index is driving the loop, try to eliminate WHERE clause
      ** terms from the query that must be true due to the WHERE clause of
      ** the partial index.  This optimization does not work on an outer join,
      ** as shown by:
      **
      ** 2019-11-02 ticket 623eff57e76d45f6      (LEFT JOIN)
      ** 2025-05-29 forum post 7dee41d32506c4ae  (RIGHT JOIN)
      */
      if( pIdx->pPartIdxWhere && pLevel->pRJ==0 ){
        whereApplyPartialIndexConstraints(pIdx->pPartIdxWhere, iCur, pWC);
      }
    }else{
      testcase( pIdx->pPartIdxWhere );
      /* The following assert() is not a requirement, merely an observation:
      ** The OR-optimization doesn't work for the right hand table of
      ** a LEFT JOIN: */
      assert( (pWInfo->wctrlFlags & (WHERE_OR_SUBCLAUSE|WHERE_RIGHT_JOIN))==0 );
    }

    /* Record the instruction used to terminate the loop. */
    if( (pLoop->wsFlags & WHERE_ONEROW)
     || (pLevel->u.in.nIn && regBignull==0 && whereLoopIsOneRow(pLoop))
    ){
      pLevel->op = OP_Noop;
    }else if( bRev ){
      pLevel->op = OP_Prev;
    }else{
      pLevel->op = OP_Next;
    }
    pLevel->p1 = iIdxCur;
    pLevel->p3 = (pLoop->wsFlags&WHERE_UNQ_WANTED)!=0 ? 1:0;
    if( (pLoop->wsFlags & WHERE_CONSTRAINT)==0 ){
      pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
    }else{
      assert( pLevel->p5==0 );
    }
    if( omitTable ) pIdx = 0;
  }else

#ifndef SQLITE_OMIT_OR_OPTIMIZATION
  if( pLoop->wsFlags & WHERE_MULTI_OR ){
    /* Case 5:  Two or more separately indexed terms connected by OR

sqlite3.c  view on Meta::CPAN

    **
    ** Added 2014-05-26: If the table is a WITHOUT ROWID table, then
    ** use an ephemeral index instead of a RowSet to record the primary
    ** keys of the rows we have already seen.
    **
    */
    WhereClause *pOrWc;    /* The OR-clause broken out into subterms */
    SrcList *pOrTab;       /* Shortened table list or OR-clause generation */
    Index *pCov = 0;             /* Potential covering index (or NULL) */
    int iCovCur = pParse->nTab++;  /* Cursor used for index scans (if any) */

    int regReturn = ++pParse->nMem;           /* Register used with OP_Gosub */
    int regRowset = 0;                        /* Register for RowSet object */
    int regRowid = 0;                         /* Register holding rowid */
    int iLoopBody = sqlite3VdbeMakeLabel(pParse);/* Start of loop body */
    int iRetInit;                             /* Address of regReturn init */
    int untestedTerms = 0;             /* Some terms not completely tested */
    int ii;                            /* Loop counter */
    Expr *pAndExpr = 0;                /* An ".. AND (...)" expression */
    Table *pTab = pTabItem->pSTab;

    pTerm = pLoop->aLTerm[0];
    assert( pTerm!=0 );
    assert( pTerm->eOperator & WO_OR );
    assert( (pTerm->wtFlags & TERM_ORINFO)!=0 );
    pOrWc = &pTerm->u.pOrInfo->wc;
    pLevel->op = OP_Return;
    pLevel->p1 = regReturn;

    /* Set up a new SrcList in pOrTab containing the table being scanned
    ** by this loop in the a[0] slot and all notReady tables in a[1..] slots.
    ** This becomes the SrcList in the recursive call to sqlite3WhereBegin().
    */
    if( pWInfo->nLevel>1 ){
      int nNotReady;                 /* The number of notReady tables */
      SrcItem *origSrc;              /* Original list of tables */
      nNotReady = pWInfo->nLevel - iLevel - 1;
      pOrTab = sqlite3DbMallocRawNN(db, SZ_SRCLIST(nNotReady+1));
      if( pOrTab==0 ) return notReady;
      pOrTab->nAlloc = (u8)(nNotReady + 1);
      pOrTab->nSrc = pOrTab->nAlloc;
      memcpy(pOrTab->a, pTabItem, sizeof(*pTabItem));
      origSrc = pWInfo->pTabList->a;
      for(k=1; k<=nNotReady; k++){
        memcpy(&pOrTab->a[k], &origSrc[pLevel[k].iFrom], sizeof(pOrTab->a[k]));
      }
    }else{
      pOrTab = pWInfo->pTabList;
    }

    /* Initialize the rowset register to contain NULL. An SQL NULL is
    ** equivalent to an empty rowset.  Or, create an ephemeral index
    ** capable of holding primary keys in the case of a WITHOUT ROWID.
    **
    ** Also initialize regReturn to contain the address of the instruction
    ** immediately following the OP_Return at the bottom of the loop. This
    ** is required in a few obscure LEFT JOIN cases where control jumps
    ** over the top of the loop into the body of it. In this case the
    ** correct response for the end-of-loop code (the OP_Return) is to
    ** fall through to the next instruction, just as an OP_Next does if
    ** called on an uninitialized cursor.
    */
    if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
      if( HasRowid(pTab) ){
        regRowset = ++pParse->nMem;
        sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset);
      }else{
        Index *pPk = sqlite3PrimaryKeyIndex(pTab);
        regRowset = pParse->nTab++;
        sqlite3VdbeAddOp2(v, OP_OpenEphemeral, regRowset, pPk->nKeyCol);
        sqlite3VdbeSetP4KeyInfo(pParse, pPk);
      }
      regRowid = ++pParse->nMem;
    }
    iRetInit = sqlite3VdbeAddOp2(v, OP_Integer, 0, regReturn);

    /* If the original WHERE clause is z of the form:  (x1 OR x2 OR ...) AND y
    ** Then for every term xN, evaluate as the subexpression: xN AND y
    ** That way, terms in y that are factored into the disjunction will
    ** be picked up by the recursive calls to sqlite3WhereBegin() below.
    **
    ** Actually, each subexpression is converted to "xN AND w" where w is
    ** the "interesting" terms of z - terms that did not originate in the
    ** ON or USING clause of a LEFT JOIN, and terms that are usable as
    ** indices.
    **
    ** This optimization also only applies if the (x1 OR x2 OR ...) term
    ** is not contained in the ON clause of a LEFT JOIN.
    ** See ticket http://sqlite.org/src/info/f2369304e4
    **
    ** 2022-02-04:  Do not push down slices of a row-value comparison.
    ** In other words, "w" or "y" may not be a slice of a vector.  Otherwise,
    ** the initialization of the right-hand operand of the vector comparison
    ** might not occur, or might occur only in an OR branch that is not
    ** taken.  dbsqlfuzz 80a9fade844b4fb43564efc972bcb2c68270f5d1.
    **
    ** 2022-03-03:  Do not push down expressions that involve subqueries.
    ** The subquery might get coded as a subroutine.  Any table-references
    ** in the subquery might be resolved to index-references for the index on
    ** the OR branch in which the subroutine is coded.  But if the subroutine
    ** is invoked from a different OR branch that uses a different index, such
    ** index-references will not work.  tag-20220303a
    ** https://sqlite.org/forum/forumpost/36937b197273d403
    */
    if( pWC->nTerm>1 ){
      int iTerm;
      for(iTerm=0; iTerm<pWC->nTerm; iTerm++){
        Expr *pExpr = pWC->a[iTerm].pExpr;
        if( &pWC->a[iTerm] == pTerm ) continue;
        testcase( pWC->a[iTerm].wtFlags & TERM_VIRTUAL );
        testcase( pWC->a[iTerm].wtFlags & TERM_CODED );
        testcase( pWC->a[iTerm].wtFlags & TERM_SLICE );
        if( (pWC->a[iTerm].wtFlags & (TERM_VIRTUAL|TERM_CODED|TERM_SLICE))!=0 ){
          continue;
        }
        if( (pWC->a[iTerm].eOperator & WO_ALL)==0 ) continue;
        if( ExprHasProperty(pExpr, EP_Subquery) ) continue;  /* tag-20220303a */
        pExpr = sqlite3ExprDup(db, pExpr, 0);
        pAndExpr = sqlite3ExprAnd(pParse, pAndExpr, pExpr);
      }
      if( pAndExpr ){

sqlite3.c  view on Meta::CPAN

            if( HasRowid(pTab) ){
              sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, -1, regRowid);
              jmp1 = sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset, 0,
                                          regRowid, iSet);
              VdbeCoverage(v);
            }else{
              Index *pPk = sqlite3PrimaryKeyIndex(pTab);
              int nPk = pPk->nKeyCol;
              int iPk;
              int r;

              /* Read the PK into an array of temp registers. */
              r = sqlite3GetTempRange(pParse, nPk);
              for(iPk=0; iPk<nPk; iPk++){
                int iCol = pPk->aiColumn[iPk];
                sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol,r+iPk);
              }

              /* Check if the temp table already contains this key. If so,
              ** the row has already been included in the result set and
              ** can be ignored (by jumping past the Gosub below). Otherwise,
              ** insert the key into the temp table and proceed with processing
              ** the row.
              **
              ** Use some of the same optimizations as OP_RowSetTest: If iSet
              ** is zero, assume that the key cannot already be present in
              ** the temp table. And if iSet is -1, assume that there is no
              ** need to insert the key into the temp table, as it will never
              ** be tested for.  */
              if( iSet ){
                jmp1 = sqlite3VdbeAddOp4Int(v, OP_Found, regRowset, 0, r, nPk);
                VdbeCoverage(v);
              }
              if( iSet>=0 ){
                sqlite3VdbeAddOp3(v, OP_MakeRecord, r, nPk, regRowid);
                sqlite3VdbeAddOp4Int(v, OP_IdxInsert, regRowset, regRowid,
                                     r, nPk);
                if( iSet ) sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
              }

              /* Release the array of temp registers */
              sqlite3ReleaseTempRange(pParse, r, nPk);
            }
          }

          /* Invoke the main loop body as a subroutine */
          sqlite3VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);

          /* Jump here (skipping the main loop body subroutine) if the
          ** current sub-WHERE row is a duplicate from prior sub-WHEREs. */
          if( jmp1 ) sqlite3VdbeJumpHere(v, jmp1);

          /* The pSubWInfo->untestedTerms flag means that this OR term
          ** contained one or more AND term from a notReady table.  The
          ** terms from the notReady table could not be tested and will
          ** need to be tested later.
          */
          if( pSubWInfo->untestedTerms ) untestedTerms = 1;

          /* If all of the OR-connected terms are optimized using the same
          ** index, and the index is opened using the same cursor number
          ** by each call to sqlite3WhereBegin() made by this loop, it may
          ** be possible to use that index as a covering index.
          **
          ** If the call to sqlite3WhereBegin() above resulted in a scan that
          ** uses an index, and this is either the first OR-connected term
          ** processed or the index is the same as that used by all previous
          ** terms, set pCov to the candidate covering index. Otherwise, set
          ** pCov to NULL to indicate that no candidate covering index will
          ** be available.
          */
          pSubLoop = pSubWInfo->a[0].pWLoop;
          assert( (pSubLoop->wsFlags & WHERE_AUTO_INDEX)==0 );
          if( (pSubLoop->wsFlags & WHERE_INDEXED)!=0
           && (ii==0 || pSubLoop->u.btree.pIndex==pCov)
           && (HasRowid(pTab) || !IsPrimaryKeyIndex(pSubLoop->u.btree.pIndex))
          ){
            assert( pSubWInfo->a[0].iIdxCur==iCovCur );
            pCov = pSubLoop->u.btree.pIndex;
          }else{
            pCov = 0;
          }
          if( sqlite3WhereUsesDeferredSeek(pSubWInfo) ){
            pWInfo->bDeferredSeek = 1;
          }

          /* Finish the loop through table entries that match term pOrTerm. */
          sqlite3WhereEnd(pSubWInfo);
          ExplainQueryPlanPop(pParse);
        }
        sqlite3ExprDelete(db, pDelete);
      }
    }
    ExplainQueryPlanPop(pParse);
    assert( pLevel->pWLoop==pLoop );
    assert( (pLoop->wsFlags & WHERE_MULTI_OR)!=0 );
    assert( (pLoop->wsFlags & WHERE_IN_ABLE)==0 );
    pLevel->u.pCoveringIdx = pCov;
    if( pCov ) pLevel->iIdxCur = iCovCur;
    if( pAndExpr ){
      pAndExpr->pLeft = 0;
      sqlite3ExprDelete(db, pAndExpr);
    }
    sqlite3VdbeChangeP1(v, iRetInit, sqlite3VdbeCurrentAddr(v));
    sqlite3VdbeGoto(v, pLevel->addrBrk);
    sqlite3VdbeResolveLabel(v, iLoopBody);

    /* Set the P2 operand of the OP_Return opcode that will end the current
    ** loop to point to this spot, which is the top of the next containing
    ** loop.  The byte-code formatter will use that P2 value as a hint to
    ** indent everything in between the this point and the final OP_Return.
    ** See tag-20220407a in vdbe.c and shell.c */
    assert( pLevel->op==OP_Return );
    pLevel->p2 = sqlite3VdbeCurrentAddr(v);

    if( pWInfo->nLevel>1 ){ sqlite3DbFreeNN(db, pOrTab); }
    if( !untestedTerms ) disableTerm(pLevel, pTerm);
  }else
#endif /* SQLITE_OMIT_OR_OPTIMIZATION */

  {
    /* Case 6:  There is no usable index.  We must do a complete
    **          scan of the entire table.
    */
    static const u8 aStep[] = { OP_Next, OP_Prev };
    static const u8 aStart[] = { OP_Rewind, OP_Last };
    assert( bRev==0 || bRev==1 );
    if( pTabItem->fg.isRecursive ){
      /* Tables marked isRecursive have only a single row that is stored in
      ** a pseudo-cursor.  No need to Rewind or Next such cursors. */
      pLevel->op = OP_Noop;
    }else{
      codeCursorHint(pTabItem, pWInfo, pLevel, 0);
      pLevel->op = aStep[bRev];
      pLevel->p1 = iCur;
      pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev],iCur,pLevel->addrHalt);
      VdbeCoverageIf(v, bRev==0);
      VdbeCoverageIf(v, bRev!=0);
      pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
    }
  }

#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
  pLevel->addrVisit = sqlite3VdbeCurrentAddr(v);
#endif

  /* Insert code to test every subexpression that can be completely
  ** computed using the current set of tables.
  **
  ** This loop may run between one and three times, depending on the
  ** constraints to be generated. The value of stack variable iLoop
  ** determines the constraints coded by each iteration, as follows:
  **
  ** iLoop==1: Code only expressions that are entirely covered by pIdx.
  ** iLoop==2: Code remaining expressions that do not contain correlated
  **           sub-queries.
  ** iLoop==3: Code all remaining expressions.
  **
  ** An effort is made to skip unnecessary iterations of the loop.
  **
  ** This optimization of causing simple query restrictions to occur before
  ** more complex one is call the "push-down" optimization in MySQL.  Here
  ** in SQLite, the name is "MySQL push-down", since there is also another
  ** totally unrelated optimization called "WHERE-clause push-down".
  ** Sometimes the qualifier is omitted, resulting in an ambiguity, so beware.
  */
  iLoop = (pIdx ? 1 : 2);
  do{
    int iNext = 0;                /* Next value for iLoop */
    for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
      Expr *pE;
      int skipLikeAddr = 0;
      testcase( pTerm->wtFlags & TERM_VIRTUAL );
      testcase( pTerm->wtFlags & TERM_CODED );
      if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
      if( (pTerm->prereqAll & pLevel->notReady)!=0 ){
        testcase( pWInfo->untestedTerms==0
            && (pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE)!=0 );
        pWInfo->untestedTerms = 1;
        continue;
      }
      pE = pTerm->pExpr;
      assert( pE!=0 );
      if( pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT) ){
        if( !ExprHasProperty(pE,EP_OuterON|EP_InnerON) ){
          /* Defer processing WHERE clause constraints until after outer
          ** join processing.  tag-20220513a */
          continue;
        }else if( (pTabItem->fg.jointype & JT_LEFT)==JT_LEFT
               && !ExprHasProperty(pE,EP_OuterON) ){

sqlite3.c  view on Meta::CPAN

  for(op=TK_EQ; eOp!=(WO_EQ<<(op-TK_EQ)); op++){ assert( op<TK_GE ); }
  pNew->op = op;
  idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC);
  exprAnalyze(pSrc, pWC, idxNew);
}

#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY)
/*
** Analyze a term that consists of two or more OR-connected
** subterms.  So in:
**
**     ... WHERE  (a=5) AND (b=7 OR c=9 OR d=13) AND (d=13)
**                          ^^^^^^^^^^^^^^^^^^^^
**
** This routine analyzes terms such as the middle term in the above example.
** A WhereOrTerm object is computed and attached to the term under
** analysis, regardless of the outcome of the analysis.  Hence:
**
**     WhereTerm.wtFlags   |=  TERM_ORINFO
**     WhereTerm.u.pOrInfo  =  a dynamically allocated WhereOrTerm object
**
** The term being analyzed must have two or more of OR-connected subterms.
** A single subterm might be a set of AND-connected sub-subterms.
** Examples of terms under analysis:
**
**     (A)     t1.x=t2.y OR t1.x=t2.z OR t1.y=15 OR t1.z=t3.a+5
**     (B)     x=expr1 OR expr2=x OR x=expr3
**     (C)     t1.x=t2.y OR (t1.x=t2.z AND t1.y=15)
**     (D)     x=expr1 OR (y>11 AND y<22 AND z LIKE '*hello*')
**     (E)     (p.a=1 AND q.b=2 AND r.c=3) OR (p.x=4 AND q.y=5 AND r.z=6)
**     (F)     x>A OR (x=A AND y>=B)
**
** CASE 1:
**
** If all subterms are of the form T.C=expr for some single column of C and
** a single table T (as shown in example B above) then create a new virtual
** term that is an equivalent IN expression.  In other words, if the term
** being analyzed is:
**
**      x = expr1  OR  expr2 = x  OR  x = expr3
**
** then create a new virtual term like this:
**
**      x IN (expr1,expr2,expr3)
**
** CASE 2:
**
** If there are exactly two disjuncts and one side has x>A and the other side
** has x=A (for the same x and A) then add a new virtual conjunct term to the
** WHERE clause of the form "x>=A".  Example:
**
**      x>A OR (x=A AND y>B)    adds:    x>=A
**
** The added conjunct can sometimes be helpful in query planning.
**
** CASE 3:
**
** If all subterms are indexable by a single table T, then set
**
**     WhereTerm.eOperator              =  WO_OR
**     WhereTerm.u.pOrInfo->indexable  |=  the cursor number for table T
**
** A subterm is "indexable" if it is of the form
** "T.C <op> <expr>" where C is any column of table T and
** <op> is one of "=", "<", "<=", ">", ">=", "IS NULL", or "IN".
** A subterm is also indexable if it is an AND of two or more
** subsubterms at least one of which is indexable.  Indexable AND
** subterms have their eOperator set to WO_AND and they have
** u.pAndInfo set to a dynamically allocated WhereAndTerm object.
**
** From another point of view, "indexable" means that the subterm could
** potentially be used with an index if an appropriate index exists.
** This analysis does not consider whether or not the index exists; that
** is decided elsewhere.  This analysis only looks at whether subterms
** appropriate for indexing exist.
**
** All examples A through E above satisfy case 3.  But if a term
** also satisfies case 1 (such as B) we know that the optimizer will
** always prefer case 1, so in that case we pretend that case 3 is not
** satisfied.
**
** It might be the case that multiple tables are indexable.  For example,
** (E) above is indexable on tables P, Q, and R.
**
** Terms that satisfy case 3 are candidates for lookup by using
** separate indices to find rowids for each subterm and composing
** the union of all rowids using a RowSet object.  This is similar
** to "bitmap indices" in other database engines.
**
** OTHERWISE:
**
** If none of cases 1, 2, or 3 apply, then leave the eOperator set to
** zero.  This term is not useful for search.
*/
static void exprAnalyzeOrTerm(
  SrcList *pSrc,            /* the FROM clause */
  WhereClause *pWC,         /* the complete WHERE clause */
  int idxTerm               /* Index of the OR-term to be analyzed */
){
  WhereInfo *pWInfo = pWC->pWInfo;        /* WHERE clause processing context */
  Parse *pParse = pWInfo->pParse;         /* Parser context */
  sqlite3 *db = pParse->db;               /* Database connection */
  WhereTerm *pTerm = &pWC->a[idxTerm];    /* The term to be analyzed */
  Expr *pExpr = pTerm->pExpr;             /* The expression of the term */
  int i;                                  /* Loop counters */
  WhereClause *pOrWc;       /* Breakup of pTerm into subterms */
  WhereTerm *pOrTerm;       /* A Sub-term within the pOrWc */
  WhereOrInfo *pOrInfo;     /* Additional information associated with pTerm */
  Bitmask chngToIN;         /* Tables that might satisfy case 1 */
  Bitmask indexable;        /* Tables that are indexable, satisfying case 2 */

  /*
  ** Break the OR clause into its separate subterms.  The subterms are
  ** stored in a WhereClause structure containing within the WhereOrInfo
  ** object that is attached to the original OR clause term.
  */
  assert( (pTerm->wtFlags & (TERM_DYNAMIC|TERM_ORINFO|TERM_ANDINFO))==0 );
  assert( pExpr->op==TK_OR );
  pTerm->u.pOrInfo = pOrInfo = sqlite3DbMallocZero(db, sizeof(*pOrInfo));
  if( pOrInfo==0 ) return;
  pTerm->wtFlags |= TERM_ORINFO;

sqlite3.c  view on Meta::CPAN

        b |= sqlite3WhereGetMask(&pWInfo->sMaskSet, pOther->leftCursor);
      }
      indexable &= b;
      if( (pOrTerm->eOperator & WO_EQ)==0 ){
        chngToIN = 0;
      }else{
        chngToIN &= b;
      }
    }
  }

  /*
  ** Record the set of tables that satisfy case 3.  The set might be
  ** empty.
  */
  pOrInfo->indexable = indexable;
  pTerm->eOperator = WO_OR;
  pTerm->leftCursor = -1;
  if( indexable ){
    pWC->hasOr = 1;
  }

  /* For a two-way OR, attempt to implementation case 2.
  */
  if( indexable && pOrWc->nTerm==2 ){
    int iOne = 0;
    WhereTerm *pOne;
    while( (pOne = whereNthSubterm(&pOrWc->a[0],iOne++))!=0 ){
      int iTwo = 0;
      WhereTerm *pTwo;
      while( (pTwo = whereNthSubterm(&pOrWc->a[1],iTwo++))!=0 ){
        whereCombineDisjuncts(pSrc, pWC, pOne, pTwo);
      }
    }
  }

  /*
  ** chngToIN holds a set of tables that *might* satisfy case 1.  But
  ** we have to do some additional checking to see if case 1 really
  ** is satisfied.
  **
  ** chngToIN will hold either 0, 1, or 2 bits.  The 0-bit case means
  ** that there is no possibility of transforming the OR clause into an
  ** IN operator because one or more terms in the OR clause contain
  ** something other than == on a column in the single table.  The 1-bit
  ** case means that every term of the OR clause is of the form
  ** "table.column=expr" for some single table.  The one bit that is set
  ** will correspond to the common table.  We still need to check to make
  ** sure the same column is used on all terms.  The 2-bit case is when
  ** the all terms are of the form "table1.column=table2.column".  It
  ** might be possible to form an IN operator with either table1.column
  ** or table2.column as the LHS if either is common to every term of
  ** the OR clause.
  **
  ** Note that terms of the form "table.column1=table.column2" (the
  ** same table on both sizes of the ==) cannot be optimized.
  */
  if( chngToIN ){
    int okToChngToIN = 0;     /* True if the conversion to IN is valid */
    int iColumn = -1;         /* Column index on lhs of IN operator */
    int iCursor = -1;         /* Table cursor common to all terms */
    int j = 0;                /* Loop counter */

    /* Search for a table and column that appears on one side or the
    ** other of the == operator in every subterm.  That table and column
    ** will be recorded in iCursor and iColumn.  There might not be any
    ** such table and column.  Set okToChngToIN if an appropriate table
    ** and column is found but leave okToChngToIN false if not found.
    */
    for(j=0; j<2 && !okToChngToIN; j++){
      Expr *pLeft = 0;
      pOrTerm = pOrWc->a;
      for(i=pOrWc->nTerm-1; i>=0; i--, pOrTerm++){
        assert( pOrTerm->eOperator & WO_EQ );
        pOrTerm->wtFlags &= ~TERM_OK;
        if( pOrTerm->leftCursor==iCursor ){
          /* This is the 2-bit case and we are on the second iteration and
          ** current term is from the first iteration.  So skip this term. */
          assert( j==1 );
          continue;
        }
        if( (chngToIN & sqlite3WhereGetMask(&pWInfo->sMaskSet,
                                            pOrTerm->leftCursor))==0 ){
          /* This term must be of the form t1.a==t2.b where t2 is in the
          ** chngToIN set but t1 is not.  This term will be either preceded
          ** or followed by an inverted copy (t2.b==t1.a).  Skip this term
          ** and use its inversion. */
          testcase( pOrTerm->wtFlags & TERM_COPIED );
          testcase( pOrTerm->wtFlags & TERM_VIRTUAL );
          assert( pOrTerm->wtFlags & (TERM_COPIED|TERM_VIRTUAL) );
          continue;
        }
        assert( (pOrTerm->eOperator & (WO_OR|WO_AND))==0 );
        iColumn = pOrTerm->u.x.leftColumn;
        iCursor = pOrTerm->leftCursor;
        pLeft = pOrTerm->pExpr->pLeft;
        break;
      }
      if( i<0 ){
        /* No candidate table+column was found.  This can only occur
        ** on the second iteration */
        assert( j==1 );
        assert( IsPowerOfTwo(chngToIN) );
        assert( chngToIN==sqlite3WhereGetMask(&pWInfo->sMaskSet, iCursor) );
        break;
      }
      testcase( j==1 );

      /* We have found a candidate table and column.  Check to see if that
      ** table and column is common to every term in the OR clause */
      okToChngToIN = 1;
      for(; i>=0 && okToChngToIN; i--, pOrTerm++){
        assert( pOrTerm->eOperator & WO_EQ );
        assert( (pOrTerm->eOperator & (WO_OR|WO_AND))==0 );
        if( pOrTerm->leftCursor!=iCursor ){
          pOrTerm->wtFlags &= ~TERM_OK;
        }else if( pOrTerm->u.x.leftColumn!=iColumn || (iColumn==XN_EXPR
               && sqlite3ExprCompare(pParse, pOrTerm->pExpr->pLeft, pLeft, -1)
        )){
          okToChngToIN = 0;
        }else{

sqlite3.c  view on Meta::CPAN

  assert( pSrc!=0 );
  if( pExpr->op==TK_IS
   && pSrc->nSrc>=2
   && (pSrc->a[0].fg.jointype & JT_LTORJ)!=0
  ){
    return 0;                                                          /* (4) */
  }
  aff1 = sqlite3ExprAffinity(pExpr->pLeft);
  aff2 = sqlite3ExprAffinity(pExpr->pRight);
  if( aff1!=aff2
   && (!sqlite3IsNumericAffinity(aff1) || !sqlite3IsNumericAffinity(aff2))
  ){
    return 0;                                                          /* (5) */
  }
  pColl = sqlite3ExprCompareCollSeq(pParse, pExpr);
  if( !sqlite3IsBinary(pColl)
   && !sqlite3ExprCollSeqMatch(pParse, pExpr->pLeft, pExpr->pRight)
  ){
    return 0;                                                          /* (6) */
  }
  return 1;
}

/*
** Recursively walk the expressions of a SELECT statement and generate
** a bitmask indicating which tables are used in that expression
** tree.
*/
static Bitmask exprSelectUsage(WhereMaskSet *pMaskSet, Select *pS){
  Bitmask mask = 0;
  while( pS ){
    SrcList *pSrc = pS->pSrc;
    mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pEList);
    mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pGroupBy);
    mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pOrderBy);
    mask |= sqlite3WhereExprUsage(pMaskSet, pS->pWhere);
    mask |= sqlite3WhereExprUsage(pMaskSet, pS->pHaving);
    if( ALWAYS(pSrc!=0) ){
      int i;
      for(i=0; i<pSrc->nSrc; i++){
        if( pSrc->a[i].fg.isSubquery ){
          mask |= exprSelectUsage(pMaskSet, pSrc->a[i].u4.pSubq->pSelect);
        }
        if( pSrc->a[i].fg.isUsing==0 ){
          mask |= sqlite3WhereExprUsage(pMaskSet, pSrc->a[i].u3.pOn);
        }
        if( pSrc->a[i].fg.isTabFunc ){
          mask |= sqlite3WhereExprListUsage(pMaskSet, pSrc->a[i].u1.pFuncArg);
        }
      }
    }
    pS = pS->pPrior;
  }
  return mask;
}

/*
** Expression pExpr is one operand of a comparison operator that might
** be useful for indexing.  This routine checks to see if pExpr appears
** in any index.  Return TRUE (1) if pExpr is an indexed term and return
** FALSE (0) if not.  If TRUE is returned, also set aiCurCol[0] to the cursor
** number of the table that is indexed and aiCurCol[1] to the column number
** of the column that is indexed, or XN_EXPR (-2) if an expression is being
** indexed.
**
** If pExpr is a TK_COLUMN column reference, then this routine always returns
** true even if that particular column is not indexed, because the column
** might be added to an automatic index later.
*/
static SQLITE_NOINLINE int exprMightBeIndexed2(
  SrcList *pFrom,        /* The FROM clause */
  int *aiCurCol,         /* Write the referenced table cursor and column here */
  Expr *pExpr,           /* An operand of a comparison operator */
  int j                  /* Start looking with the j-th pFrom entry */
){
  Index *pIdx;
  int i;
  int iCur;
  do{
    iCur = pFrom->a[j].iCursor;
    for(pIdx=pFrom->a[j].pSTab->pIndex; pIdx; pIdx=pIdx->pNext){
      if( pIdx->aColExpr==0 ) continue;
      for(i=0; i<pIdx->nKeyCol; i++){
        if( pIdx->aiColumn[i]!=XN_EXPR ) continue;
        assert( pIdx->bHasExpr );
        if( sqlite3ExprCompareSkip(pExpr,pIdx->aColExpr->a[i].pExpr,iCur)==0
         && !sqlite3ExprIsConstant(0,pIdx->aColExpr->a[i].pExpr)
        ){
          aiCurCol[0] = iCur;
          aiCurCol[1] = XN_EXPR;
          return 1;
        }
      }
    }
  }while( ++j < pFrom->nSrc );
  return 0;
}
static int exprMightBeIndexed(
  SrcList *pFrom,        /* The FROM clause */
  int *aiCurCol,         /* Write the referenced table cursor & column here */
  Expr *pExpr,           /* An operand of a comparison operator */
  int op                 /* The specific comparison operator */
){
  int i;

  /* If this expression is a vector to the left or right of a
  ** inequality constraint (>, <, >= or <=), perform the processing
  ** on the first element of the vector.  */
  assert( TK_GT+1==TK_LE && TK_GT+2==TK_LT && TK_GT+3==TK_GE );
  assert( TK_IS<TK_GE && TK_ISNULL<TK_GE && TK_IN<TK_GE );
  assert( op<=TK_GE );
  if( pExpr->op==TK_VECTOR && (op>=TK_GT && ALWAYS(op<=TK_GE)) ){
    assert( ExprUseXList(pExpr) );
    pExpr = pExpr->x.pList->a[0].pExpr;
  }

  if( pExpr->op==TK_COLUMN ){
    aiCurCol[0] = pExpr->iTable;
    aiCurCol[1] = pExpr->iColumn;
    return 1;
  }

  for(i=0; i<pFrom->nSrc; i++){
    Index *pIdx;
    for(pIdx=pFrom->a[i].pSTab->pIndex; pIdx; pIdx=pIdx->pNext){
      if( pIdx->aColExpr ){
        return exprMightBeIndexed2(pFrom,aiCurCol,pExpr,i);
      }
    }
  }
  return 0;
}


/*
** The input to this routine is an WhereTerm structure with only the
** "pExpr" field filled in.  The job of this routine is to analyze the
** subexpression and populate all the other fields of the WhereTerm
** structure.
**
** If the expression is of the form "<expr> <op> X" it gets commuted
** to the standard form of "X <op> <expr>".
**
** If the expression is of the form "X <op> Y" where both X and Y are
** columns, then the original expression is unchanged and a new virtual
** term of the form "Y <op> X" is added to the WHERE clause and
** analyzed separately.  The original term is marked with TERM_COPIED
** and the new term is marked with TERM_DYNAMIC (because it's pExpr
** needs to be freed with the WhereClause) and TERM_VIRTUAL (because it
** is a commuted copy of a prior term.)  The original term has nChild=1
** and the copy has idxParent set to the index of the original term.
*/
static void exprAnalyze(
  SrcList *pSrc,            /* the FROM clause */
  WhereClause *pWC,         /* the WHERE clause */
  int idxTerm               /* Index of the term to be analyzed */
){
  WhereInfo *pWInfo = pWC->pWInfo; /* WHERE clause processing context */
  WhereTerm *pTerm;                /* The term to be analyzed */
  WhereMaskSet *pMaskSet;          /* Set of table index masks */

sqlite3.c  view on Meta::CPAN

    /* The ORDER BY LIMIT optimization does not apply.  Jump to the
    ** continuation of the inner-most loop. */
    return pWInfo->iContinue;
  }
  pInner = &pWInfo->a[pWInfo->nLevel-1];
  assert( pInner->addrNxt!=0 );
  return pInner->pRJ ? pWInfo->iContinue : pInner->addrNxt;
}

/*
** While generating code for the min/max optimization, after handling
** the aggregate-step call to min() or max(), check to see if any
** additional looping is required.  If the output order is such that
** we are certain that the correct answer has already been found, then
** code an OP_Goto to by pass subsequent processing.
**
** Any extra OP_Goto that is coded here is an optimization.  The
** correct answer should be obtained regardless.  This OP_Goto just
** makes the answer appear faster.
*/
SQLITE_PRIVATE void sqlite3WhereMinMaxOptEarlyOut(Vdbe *v, WhereInfo *pWInfo){
  WhereLevel *pInner;
  int i;
  if( !pWInfo->bOrderedInnerLoop ) return;
  if( pWInfo->nOBSat==0 ) return;
  for(i=pWInfo->nLevel-1; i>=0; i--){
    pInner = &pWInfo->a[i];
    if( (pInner->pWLoop->wsFlags & WHERE_COLUMN_IN)!=0 ){
      sqlite3VdbeGoto(v, pInner->addrNxt);
      return;
    }
  }
  sqlite3VdbeGoto(v, pWInfo->iBreak);
}

/*
** Return the VDBE address or label to jump to in order to continue
** immediately with the next row of a WHERE clause.
*/
SQLITE_PRIVATE int sqlite3WhereContinueLabel(WhereInfo *pWInfo){
  assert( pWInfo->iContinue!=0 );
  return pWInfo->iContinue;
}

/*
** Return the VDBE address or label to jump to in order to break
** out of a WHERE loop.
*/
SQLITE_PRIVATE int sqlite3WhereBreakLabel(WhereInfo *pWInfo){
  return pWInfo->iBreak;
}

/*
** Return ONEPASS_OFF (0) if an UPDATE or DELETE statement is unable to
** operate directly on the rowids returned by a WHERE clause.  Return
** ONEPASS_SINGLE (1) if the statement can operation directly because only
** a single row is to be changed.  Return ONEPASS_MULTI (2) if the one-pass
** optimization can be used on multiple
**
** If the ONEPASS optimization is used (if this routine returns true)
** then also write the indices of open cursors used by ONEPASS
** into aiCur[0] and aiCur[1].  iaCur[0] gets the cursor of the data
** table and iaCur[1] gets the cursor used by an auxiliary index.
** Either value may be -1, indicating that cursor is not used.
** Any cursors returned will have been opened for writing.
**
** aiCur[0] and aiCur[1] both get -1 if the where-clause logic is
** unable to use the ONEPASS optimization.
*/
SQLITE_PRIVATE int sqlite3WhereOkOnePass(WhereInfo *pWInfo, int *aiCur){
  memcpy(aiCur, pWInfo->aiCurOnePass, sizeof(int)*2);
#ifdef WHERETRACE_ENABLED
  if( sqlite3WhereTrace && pWInfo->eOnePass!=ONEPASS_OFF ){
    sqlite3DebugPrintf("%s cursors: %d %d\n",
         pWInfo->eOnePass==ONEPASS_SINGLE ? "ONEPASS_SINGLE" : "ONEPASS_MULTI",
         aiCur[0], aiCur[1]);
  }
#endif
  return pWInfo->eOnePass;
}

/*
** Return TRUE if the WHERE loop uses the OP_DeferredSeek opcode to move
** the data cursor to the row selected by the index cursor.
*/
SQLITE_PRIVATE int sqlite3WhereUsesDeferredSeek(WhereInfo *pWInfo){
  return pWInfo->bDeferredSeek;
}

/*
** Move the content of pSrc into pDest
*/
static void whereOrMove(WhereOrSet *pDest, WhereOrSet *pSrc){
  pDest->n = pSrc->n;
  memcpy(pDest->a, pSrc->a, pDest->n*sizeof(pDest->a[0]));
}

/*
** Try to insert a new prerequisite/cost entry into the WhereOrSet pSet.
**
** The new entry might overwrite an existing entry, or it might be
** appended, or it might be discarded.  Do whatever is the right thing
** so that pSet keeps the N_OR_COST best entries seen so far.
*/
static int whereOrInsert(
  WhereOrSet *pSet,      /* The WhereOrSet to be updated */
  Bitmask prereq,        /* Prerequisites of the new entry */
  LogEst rRun,           /* Run-cost of the new entry */
  LogEst nOut            /* Number of outputs for the new entry */
){
  u16 i;
  WhereOrCost *p;
  for(i=pSet->n, p=pSet->a; i>0; i--, p++){
    if( rRun<=p->rRun && (prereq & p->prereq)==prereq ){
      goto whereOrInsert_done;
    }
    if( p->rRun<=rRun && (p->prereq & prereq)==p->prereq ){
      return 0;
    }
  }
  if( pSet->n<N_OR_COST ){
    p = &pSet->a[pSet->n++];
    p->nOut = nOut;
  }else{
    p = pSet->a;
    for(i=1; i<pSet->n; i++){
      if( p->rRun>pSet->a[i].rRun ) p = pSet->a + i;
    }
    if( p->rRun<=rRun ) return 0;
  }
whereOrInsert_done:
  p->prereq = prereq;
  p->rRun = rRun;
  if( p->nOut>nOut ) p->nOut = nOut;
  return 1;
}

/*
** Return the bitmask for the given cursor number.  Return 0 if
** iCursor is not in the set.
*/
SQLITE_PRIVATE Bitmask sqlite3WhereGetMask(WhereMaskSet *pMaskSet, int iCursor){
  int i;
  assert( pMaskSet->n<=(int)sizeof(Bitmask)*8 );
  assert( pMaskSet->n>0 || pMaskSet->ix[0]<0 );
  assert( iCursor>=-1 );
  if( pMaskSet->ix[0]==iCursor ){
    return 1;
  }
  for(i=1; i<pMaskSet->n; i++){
    if( pMaskSet->ix[i]==iCursor ){
      return MASKBIT(i);
    }
  }
  return 0;
}

/* Allocate memory that is automatically freed when pWInfo is freed.
*/
SQLITE_PRIVATE void *sqlite3WhereMalloc(WhereInfo *pWInfo, u64 nByte){
  WhereMemBlock *pBlock;
  pBlock = sqlite3DbMallocRawNN(pWInfo->pParse->db, nByte+sizeof(*pBlock));
  if( pBlock ){
    pBlock->pNext = pWInfo->pMemToFree;
    pBlock->sz = nByte;
    pWInfo->pMemToFree = pBlock;
    pBlock++;
  }
  return (void*)pBlock;
}
SQLITE_PRIVATE void *sqlite3WhereRealloc(WhereInfo *pWInfo, void *pOld, u64 nByte){
  void *pNew = sqlite3WhereMalloc(pWInfo, nByte);
  if( pNew && pOld ){
    WhereMemBlock *pOldBlk = (WhereMemBlock*)pOld;
    pOldBlk--;
    assert( pOldBlk->sz<nByte );
    memcpy(pNew, pOld, pOldBlk->sz);
  }
  return pNew;
}

/*
** Create a new mask for cursor iCursor.
**
** There is one cursor per table in the FROM clause.  The number of
** tables in the FROM clause is limited by a test early in the
** sqlite3WhereBegin() routine.  So we know that the pMaskSet->ix[]
** array will never overflow.
*/
static void createMask(WhereMaskSet *pMaskSet, int iCursor){
  assert( pMaskSet->n < ArraySize(pMaskSet->ix) );
  pMaskSet->ix[pMaskSet->n++] = iCursor;
}

/*
** If the right-hand branch of the expression is a TK_COLUMN, then return
** a pointer to the right-hand branch.  Otherwise, return NULL.
*/
static Expr *whereRightSubexprIsColumn(Expr *p){
  p = sqlite3ExprSkipCollateAndLikely(p->pRight);
  if( ALWAYS(p!=0) && p->op==TK_COLUMN && !ExprHasProperty(p, EP_FixedCol) ){
    return p;
  }
  return 0;
}

/*
** Term pTerm is guaranteed to be a WO_IN term. It may be a component term
** of a vector IN expression of the form "(x, y, ...) IN (SELECT ...)".
** This function checks to see if the term is compatible with an index
** column with affinity idxaff (one of the SQLITE_AFF_XYZ values). If so,
** it returns a pointer to the name of the collation sequence (e.g. "BINARY"
** or "NOCASE") used by the comparison in pTerm. If it is not compatible
** with affinity idxaff, NULL is returned.
*/
static SQLITE_NOINLINE const char *indexInAffinityOk(
  Parse *pParse,
  WhereTerm *pTerm,
  u8 idxaff
){
  Expr *pX = pTerm->pExpr;
  Expr inexpr;

  assert( pTerm->eOperator & WO_IN );

  if( sqlite3ExprIsVector(pX->pLeft) ){
    int iField = pTerm->u.x.iField - 1;
    inexpr.flags = 0;
    inexpr.op = TK_EQ;
    inexpr.pLeft = pX->pLeft->x.pList->a[iField].pExpr;
    assert( ExprUseXSelect(pX) );
    inexpr.pRight = pX->x.pSelect->pEList->a[iField].pExpr;
    pX = &inexpr;
  }

  if( sqlite3IndexAffinityOk(pX, idxaff) ){
    CollSeq *pRet = sqlite3ExprCompareCollSeq(pParse, pX);
    return pRet ? pRet->zName : sqlite3StrBINARY;
  }
  return 0;
}

/*
** Advance to the next WhereTerm that matches according to the criteria
** established when the pScan object was initialized by whereScanInit().
** Return NULL if there are no more matching WhereTerms.
*/
static WhereTerm *whereScanNext(WhereScan *pScan){
  int iCur;            /* The cursor on the LHS of the term */
  i16 iColumn;         /* The column on the LHS of the term.  -1 for IPK */
  Expr *pX;            /* An expression being tested */
  WhereClause *pWC;    /* Shorthand for pScan->pWC */
  WhereTerm *pTerm;    /* The term being tested */
  int k = pScan->k;    /* Where to start scanning */

  assert( pScan->iEquiv<=pScan->nEquiv );
  pWC = pScan->pWC;
  while(1){
    iColumn = pScan->aiColumn[pScan->iEquiv-1];
    iCur = pScan->aiCur[pScan->iEquiv-1];
    assert( pWC!=0 );
    assert( iCur>=0 );
    do{
      for(pTerm=pWC->a+k; k<pWC->nTerm; k++, pTerm++){
        assert( (pTerm->eOperator & (WO_OR|WO_AND))==0 || pTerm->leftCursor<0 );
        if( pTerm->leftCursor==iCur
         && pTerm->u.x.leftColumn==iColumn
         && (iColumn!=XN_EXPR
             || sqlite3ExprCompareSkip(pTerm->pExpr->pLeft,
                                       pScan->pIdxExpr,iCur)==0)
         && (pScan->iEquiv<=1 || !ExprHasProperty(pTerm->pExpr, EP_OuterON))
        ){
          if( (pTerm->eOperator & WO_EQUIV)!=0
           && pScan->nEquiv<ArraySize(pScan->aiCur)
           && (pX = whereRightSubexprIsColumn(pTerm->pExpr))!=0
          ){
            int j;
            for(j=0; j<pScan->nEquiv; j++){
              if( pScan->aiCur[j]==pX->iTable
               && pScan->aiColumn[j]==pX->iColumn ){
                  break;
              }
            }
            if( j==pScan->nEquiv ){
              pScan->aiCur[j] = pX->iTable;
              pScan->aiColumn[j] = pX->iColumn;
              pScan->nEquiv++;
            }
          }
          if( (pTerm->eOperator & pScan->opMask)!=0 ){
            /* Verify the affinity and collating sequence match */
            if( pScan->zCollName && (pTerm->eOperator & WO_ISNULL)==0 ){
              const char *zCollName;
              Parse *pParse = pWC->pWInfo->pParse;
              pX = pTerm->pExpr;

              if( (pTerm->eOperator & WO_IN) ){
                zCollName = indexInAffinityOk(pParse, pTerm, pScan->idxaff);
                if( !zCollName ) continue;
              }else{
                CollSeq *pColl;
                if( !sqlite3IndexAffinityOk(pX, pScan->idxaff) ){
                  continue;
                }
                assert(pX->pLeft);
                pColl = sqlite3ExprCompareCollSeq(pParse, pX);
                zCollName = pColl ? pColl->zName : sqlite3StrBINARY;
              }

sqlite3.c  view on Meta::CPAN

  pTab = pTabList->a[0].pSTab;

  /* If any of the expressions is an IPK column on table iBase, then return
  ** true. Note: The (p->iTable==iBase) part of this test may be false if the
  ** current SELECT is a correlated sub-query.
  */
  for(i=0; i<pDistinct->nExpr; i++){
    Expr *p = sqlite3ExprSkipCollateAndLikely(pDistinct->a[i].pExpr);
    if( NEVER(p==0) ) continue;
    if( p->op!=TK_COLUMN && p->op!=TK_AGG_COLUMN ) continue;
    if( p->iTable==iBase && p->iColumn<0 ) return 1;
  }

  /* Loop through all indices on the table, checking each to see if it makes
  ** the DISTINCT qualifier redundant. It does so if:
  **
  **   1. The index is itself UNIQUE, and
  **
  **   2. All of the columns in the index are either part of the pDistinct
  **      list, or else the WHERE clause contains a term of the form "col=X",
  **      where X is a constant value. The collation sequences of the
  **      comparison and select-list expressions must match those of the index.
  **
  **   3. All of those index columns for which the WHERE clause does not
  **      contain a "col=X" term are subject to a NOT NULL constraint.
  */
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    if( !IsUniqueIndex(pIdx) ) continue;
    if( pIdx->pPartIdxWhere ) continue;
    for(i=0; i<pIdx->nKeyCol; i++){
      if( 0==sqlite3WhereFindTerm(pWC, iBase, i, ~(Bitmask)0, WO_EQ, pIdx) ){
        if( findIndexCol(pParse, pDistinct, iBase, pIdx, i)<0 ) break;
        if( indexColumnNotNull(pIdx, i)==0 ) break;
      }
    }
    if( i==pIdx->nKeyCol ){
      /* This index implies that the DISTINCT qualifier is redundant. */
      return 1;
    }
  }

  return 0;
}


/*
** Estimate the logarithm of the input value to base 2.
*/
static LogEst estLog(LogEst N){
  return N<=10 ? 0 : sqlite3LogEst(N) - 33;
}

/*
** Convert OP_Column opcodes to OP_Copy in previously generated code.
**
** This routine runs over generated VDBE code and translates OP_Column
** opcodes into OP_Copy when the table is being accessed via co-routine
** instead of via table lookup.
**
** If the iAutoidxCur is not zero, then any OP_Rowid instructions on
** cursor iTabCur are transformed into OP_Sequence opcode for the
** iAutoidxCur cursor, in order to generate unique rowids for the
** automatic index being generated.
*/
static void translateColumnToCopy(
  Parse *pParse,      /* Parsing context */
  int iStart,         /* Translate from this opcode to the end */
  int iTabCur,        /* OP_Column/OP_Rowid references to this table */
  int iRegister,      /* The first column is in this register */
  int iAutoidxCur     /* If non-zero, cursor of autoindex being generated */
){
  Vdbe *v = pParse->pVdbe;
  VdbeOp *pOp = sqlite3VdbeGetOp(v, iStart);
  int iEnd = sqlite3VdbeCurrentAddr(v);
  if( pParse->db->mallocFailed ) return;
#ifdef SQLITE_DEBUG
  if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
    printf("CHECKING for column-to-copy on cursor %d for %d..%d\n",
            iTabCur, iStart, iEnd);
  }
#endif
  for(; iStart<iEnd; iStart++, pOp++){
    if( pOp->p1!=iTabCur ) continue;
    if( pOp->opcode==OP_Column ){
#ifdef SQLITE_DEBUG
      if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
        printf("TRANSLATE OP_Column to OP_Copy at %d\n", iStart);
      }
#endif
      pOp->opcode = OP_Copy;
      pOp->p1 = pOp->p2 + iRegister;
      pOp->p2 = pOp->p3;
      pOp->p3 = 0;
      pOp->p5 = 2;  /* Cause the MEM_Subtype flag to be cleared */
    }else if( pOp->opcode==OP_Rowid ){
#ifdef SQLITE_DEBUG
      if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
        printf("TRANSLATE OP_Rowid to OP_Sequence at %d\n", iStart);
      }
#endif
      pOp->opcode = OP_Sequence;
      pOp->p1 = iAutoidxCur;
#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
      if( iAutoidxCur==0 ){
        pOp->opcode = OP_Null;
        pOp->p3 = 0;
      }
#endif
    }
  }
}

/*
** Two routines for printing the content of an sqlite3_index_info
** structure.  Used for testing and debugging only.  If neither
** SQLITE_TEST or SQLITE_DEBUG are defined, then these routines
** are no-ops.
*/
#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(WHERETRACE_ENABLED)
static void whereTraceIndexInfoInputs(
  sqlite3_index_info *p,   /* The IndexInfo object */
  Table *pTab              /* The TABLE that is the virtual table */
){
  int i;
  if( (sqlite3WhereTrace & 0x10)==0 ) return;
  sqlite3DebugPrintf("sqlite3_index_info inputs for %s:\n", pTab->zName);
  for(i=0; i<p->nConstraint; i++){
    sqlite3DebugPrintf(
       "  constraint[%d]: col=%d termid=%d op=%d usabled=%d collseq=%s\n",
       i,
       p->aConstraint[i].iColumn,
       p->aConstraint[i].iTermOffset,
       p->aConstraint[i].op,
       p->aConstraint[i].usable,
       sqlite3_vtab_collation(p,i));
  }
  for(i=0; i<p->nOrderBy; i++){
    sqlite3DebugPrintf("  orderby[%d]: col=%d desc=%d\n",

sqlite3.c  view on Meta::CPAN

#ifndef SQLITE_OMIT_AUTOMATIC_INDEX

#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
/*
** Argument pIdx represents an automatic index that the current statement
** will create and populate. Add an OP_Explain with text of the form:
**
**     CREATE AUTOMATIC INDEX ON <table>(<cols>) [WHERE <expr>]
**
** This is only required if sqlite3_stmt_scanstatus() is enabled, to
** associate an SQLITE_SCANSTAT_NCYCLE and SQLITE_SCANSTAT_NLOOP
** values with. In order to avoid breaking legacy code and test cases,
** the OP_Explain is not added if this is an EXPLAIN QUERY PLAN command.
*/
static void explainAutomaticIndex(
  Parse *pParse,
  Index *pIdx,                    /* Automatic index to explain */
  int bPartial,                   /* True if pIdx is a partial index */
  int *pAddrExplain               /* OUT: Address of OP_Explain */
){
  if( IS_STMT_SCANSTATUS(pParse->db) && pParse->explain!=2 ){
    Table *pTab = pIdx->pTable;
    const char *zSep = "";
    char *zText = 0;
    int ii = 0;
    sqlite3_str *pStr = sqlite3_str_new(pParse->db);
    sqlite3_str_appendf(pStr,"CREATE AUTOMATIC INDEX ON %s(", pTab->zName);
    assert( pIdx->nColumn>1 );
    assert( pIdx->aiColumn[pIdx->nColumn-1]==XN_ROWID || !HasRowid(pTab) );
    for(ii=0; ii<(pIdx->nColumn-1); ii++){
      const char *zName = 0;
      int iCol = pIdx->aiColumn[ii];

      zName = pTab->aCol[iCol].zCnName;
      sqlite3_str_appendf(pStr, "%s%s", zSep, zName);
      zSep = ", ";
    }
    zText = sqlite3_str_finish(pStr);
    if( zText==0 ){
      sqlite3OomFault(pParse->db);
    }else{
      *pAddrExplain = sqlite3VdbeExplain(
          pParse, 0, "%s)%s", zText, (bPartial ? " WHERE <expr>" : "")
      );
      sqlite3_free(zText);
    }
  }
}
#else
# define explainAutomaticIndex(a,b,c,d)
#endif

/*
** Generate code to construct the Index object for an automatic index
** and to set up the WhereLevel object pLevel so that the code generator
** makes use of the automatic index.
*/
static SQLITE_NOINLINE void constructAutomaticIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  const Bitmask notReady,     /* Mask of cursors that are not available */
  WhereLevel *pLevel          /* Write new index here */
){
  int nKeyCol;                /* Number of columns in the constructed index */
  WhereTerm *pTerm;           /* A single term of the WHERE clause */
  WhereTerm *pWCEnd;          /* End of pWC->a[] */
  Index *pIdx;                /* Object describing the transient index */
  Vdbe *v;                    /* Prepared statement under construction */
  int addrInit;               /* Address of the initialization bypass jump */
  Table *pTable;              /* The table being indexed */
  int addrTop;                /* Top of the index fill loop */
  int regRecord;              /* Register holding an index record */
  int n;                      /* Column counter */
  int i;                      /* Loop counter */
  int mxBitCol;               /* Maximum column in pSrc->colUsed */
  CollSeq *pColl;             /* Collating sequence to on a column */
  WhereLoop *pLoop;           /* The Loop object */
  char *zNotUsed;             /* Extra space on the end of pIdx */
  Bitmask idxCols;            /* Bitmap of columns used for indexing */
  Bitmask extraCols;          /* Bitmap of additional columns */
  u8 sentWarning = 0;         /* True if a warning has been issued */
  u8 useBloomFilter = 0;      /* True to also add a Bloom filter */
  Expr *pPartial = 0;         /* Partial Index Expression */
  int iContinue = 0;          /* Jump here to skip excluded rows */
  SrcList *pTabList;          /* The complete FROM clause */
  SrcItem *pSrc;              /* The FROM clause term to get the next index */
  int addrCounter = 0;        /* Address where integer counter is initialized */
  int regBase;                /* Array of registers where record is assembled */
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
  int addrExp = 0;            /* Address of OP_Explain */
#endif

  /* Generate code to skip over the creation and initialization of the
  ** transient index on 2nd and subsequent iterations of the loop. */
  v = pParse->pVdbe;
  assert( v!=0 );
  addrInit = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);

  /* Count the number of columns that will be added to the index
  ** and used to match WHERE clause constraints */
  nKeyCol = 0;
  pTabList = pWC->pWInfo->pTabList;
  pSrc = &pTabList->a[pLevel->iFrom];
  pTable = pSrc->pSTab;
  pWCEnd = &pWC->a[pWC->nTerm];
  pLoop = pLevel->pWLoop;
  idxCols = 0;
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    Expr *pExpr = pTerm->pExpr;
    /* Make the automatic index a partial index if there are terms in the
    ** WHERE clause (or the ON clause of a LEFT join) that constrain which
    ** rows of the target table (pSrc) that can be used. */
    if( (pTerm->wtFlags & TERM_VIRTUAL)==0
     && sqlite3ExprIsSingleTableConstraint(pExpr, pTabList, pLevel->iFrom, 0)
    ){
      pPartial = sqlite3ExprAnd(pParse, pPartial,
                                sqlite3ExprDup(pParse->db, pExpr, 0));
    }
    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
      int iCol;
      Bitmask cMask;

sqlite3.c  view on Meta::CPAN

){
  int i;
  WhereTerm *pTerm;
  Parse *pParse;

  if( jointype & JT_LTORJ ) return 0;
  pParse = pWC->pWInfo->pParse;
  while( pWhere->op==TK_AND ){
    if( !whereUsablePartialIndex(iTab,jointype,pWC,pWhere->pLeft) ) return 0;
    pWhere = pWhere->pRight;
  }
  for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
    Expr *pExpr;
    pExpr = pTerm->pExpr;
    if( (!ExprHasProperty(pExpr, EP_OuterON) || pExpr->w.iJoin==iTab)
     && ((jointype & JT_OUTER)==0 || ExprHasProperty(pExpr, EP_OuterON))
     && sqlite3ExprImpliesExpr(pParse, pExpr, pWhere, iTab)
     && !sqlite3ExprImpliesExpr(pParse, pExpr, pWhere, -1)
     && (pTerm->wtFlags & TERM_VNULL)==0
    ){
      return 1;
    }
  }
  return 0;
}

/*
** pIdx is an index containing expressions.  Check it see if any of the
** expressions in the index match the pExpr expression.
*/
static int exprIsCoveredByIndex(
  const Expr *pExpr,
  const Index *pIdx,
  int iTabCur
){
  int i;
  for(i=0; i<pIdx->nColumn; i++){
    if( pIdx->aiColumn[i]==XN_EXPR
     && sqlite3ExprCompare(0, pExpr, pIdx->aColExpr->a[i].pExpr, iTabCur)==0
    ){
      return 1;
    }
  }
  return 0;
}

/*
** Structure passed to the whereIsCoveringIndex Walker callback.
*/
typedef struct CoveringIndexCheck CoveringIndexCheck;
struct CoveringIndexCheck {
  Index *pIdx;       /* The index */
  int iTabCur;       /* Cursor number for the corresponding table */
  u8 bExpr;          /* Uses an indexed expression */
  u8 bUnidx;         /* Uses an unindexed column not within an indexed expr */
};

/*
** Information passed in is pWalk->u.pCovIdxCk.  Call it pCk.
**
** If the Expr node references the table with cursor pCk->iTabCur, then
** make sure that column is covered by the index pCk->pIdx.  We know that
** all columns less than 63 (really BMS-1) are covered, so we don't need
** to check them.  But we do need to check any column at 63 or greater.
**
** If the index does not cover the column, then set pWalk->eCode to
** non-zero and return WRC_Abort to stop the search.
**
** If this node does not disprove that the index can be a covering index,
** then just return WRC_Continue, to continue the search.
**
** If pCk->pIdx contains indexed expressions and one of those expressions
** matches pExpr, then prune the search.
*/
static int whereIsCoveringIndexWalkCallback(Walker *pWalk, Expr *pExpr){
  int i;                    /* Loop counter */
  const Index *pIdx;        /* The index of interest */
  const i16 *aiColumn;      /* Columns contained in the index */
  u16 nColumn;              /* Number of columns in the index */
  CoveringIndexCheck *pCk;  /* Info about this search */

  pCk = pWalk->u.pCovIdxCk;
  pIdx = pCk->pIdx;
  if( (pExpr->op==TK_COLUMN || pExpr->op==TK_AGG_COLUMN) ){
    /* if( pExpr->iColumn<(BMS-1) && pIdx->bHasExpr==0 ) return WRC_Continue;*/
    if( pExpr->iTable!=pCk->iTabCur ) return WRC_Continue;
    pIdx = pWalk->u.pCovIdxCk->pIdx;
    aiColumn = pIdx->aiColumn;
    nColumn = pIdx->nColumn;
    for(i=0; i<nColumn; i++){
      if( aiColumn[i]==pExpr->iColumn ) return WRC_Continue;
    }
    pCk->bUnidx = 1;
    return WRC_Abort;
  }else if( pIdx->bHasExpr
         && exprIsCoveredByIndex(pExpr, pIdx, pWalk->u.pCovIdxCk->iTabCur) ){
    pCk->bExpr = 1;
    return WRC_Prune;
  }
  return WRC_Continue;
}


/*
** pIdx is an index that covers all of the low-number columns used by
** pWInfo->pSelect (columns from 0 through 62) or an index that has
** expressions terms.  Hence, we cannot determine whether or not it is
** a covering index by using the colUsed bitmasks.  We have to do a search
** to see if the index is covering.  This routine does that search.
**
** The return value is one of these:
**
**      0                The index is definitely not a covering index
**
**      WHERE_IDX_ONLY   The index is definitely a covering index
**
**      WHERE_EXPRIDX    The index is likely a covering index, but it is
**                       difficult to determine precisely because of the
**                       expressions that are indexed.  Score it as a
**                       covering index, but still keep the main table open
**                       just in case we need it.

sqlite3.c  view on Meta::CPAN

        }else if( m==0
           && (HasRowid(pTab) || pWInfo->pSelect!=0 || sqlite3FaultSim(700))
        ){
          WHERETRACE(0x200,
             ("-> %s is a covering index according to bitmasks\n",
             pProbe->zName, m==0 ? "is" : "is not"));
          pNew->wsFlags = WHERE_IDX_ONLY | WHERE_INDEXED;
        }
      }

      /* Full scan via index */
      if( b
       || !HasRowid(pTab)
       || pProbe->pPartIdxWhere!=0
       || pSrc->fg.isIndexedBy
       || ( m==0
         && pProbe->bUnordered==0
         && (pProbe->szIdxRow<pTab->szTabRow)
         && (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0
         && sqlite3GlobalConfig.bUseCis
         && OptimizationEnabled(pWInfo->pParse->db, SQLITE_CoverIdxScan)
          )
      ){
        pNew->iSortIdx = b ? iSortIdx : 0;

        /* The cost of visiting the index rows is N*K, where K is
        ** between 1.1 and 3.0, depending on the relative sizes of the
        ** index and table rows. */
        pNew->rRun = rSize + 1 + (15*pProbe->szIdxRow)/pTab->szTabRow;
        if( m!=0 ){
          /* If this is a non-covering index scan, add in the cost of
          ** doing table lookups.  The cost will be 3x the number of
          ** lookups.  Take into account WHERE clause terms that can be
          ** satisfied using just the index, and that do not require a
          ** table lookup. */
          LogEst nLookup = rSize + 16;  /* Base cost:  N*3 */
          int ii;
          int iCur = pSrc->iCursor;
          WhereClause *pWC2 = &pWInfo->sWC;
          for(ii=0; ii<pWC2->nTerm; ii++){
            WhereTerm *pTerm = &pWC2->a[ii];
            if( !sqlite3ExprCoveredByIndex(pTerm->pExpr, iCur, pProbe) ){
              break;
            }
            /* pTerm can be evaluated using just the index.  So reduce
            ** the expected number of table lookups accordingly */
            if( pTerm->truthProb<=0 ){
              nLookup += pTerm->truthProb;
            }else{
              nLookup--;
              if( pTerm->eOperator & (WO_EQ|WO_IS) ) nLookup -= 19;
            }
          }

          pNew->rRun = sqlite3LogEstAdd(pNew->rRun, nLookup);
        }
        ApplyCostMultiplier(pNew->rRun, pTab->costMult);
        whereLoopOutputAdjust(pWC, pNew, rSize);
        if( (pSrc->fg.jointype & JT_RIGHT)!=0 && pProbe->aColExpr ){
          /* Do not do an SCAN of a index-on-expression in a RIGHT JOIN
          ** because the cursor used to access the index might not be
          ** positioned to the correct row during the right-join no-match
          ** loop. */
        }else{
          rc = whereLoopInsert(pBuilder, pNew);
        }
        pNew->nOut = rSize;
        if( rc ) break;
      }
    }

    pBuilder->bldFlags1 = 0;
    rc = whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, 0);
    if( pBuilder->bldFlags1==SQLITE_BLDF1_INDEXED ){
      /* If a non-unique index is used, or if a prefix of the key for
      ** unique index is used (making the index functionally non-unique)
      ** then the sqlite_stat1 data becomes important for scoring the
      ** plan */
      pTab->tabFlags |= TF_MaybeReanalyze;
    }
#ifdef SQLITE_ENABLE_STAT4
    sqlite3Stat4ProbeFree(pBuilder->pRec);
    pBuilder->nRecValid = 0;
    pBuilder->pRec = 0;
#endif
  }
  return rc;
}

#ifndef SQLITE_OMIT_VIRTUALTABLE

/*
** Return true if pTerm is a virtual table LIMIT or OFFSET term.
*/
static int isLimitTerm(WhereTerm *pTerm){
  assert( pTerm->eOperator==WO_AUX || pTerm->eMatchOp==0 );
  return pTerm->eMatchOp>=SQLITE_INDEX_CONSTRAINT_LIMIT
      && pTerm->eMatchOp<=SQLITE_INDEX_CONSTRAINT_OFFSET;
}

/*
** Return true if the first nCons constraints in the pUsage array are
** marked as in-use (have argvIndex>0). False otherwise.
*/
static int allConstraintsUsed(
  struct sqlite3_index_constraint_usage *aUsage,
  int nCons
){
  int ii;
  for(ii=0; ii<nCons; ii++){
    if( aUsage[ii].argvIndex<=0 ) return 0;
  }
  return 1;
}

/*
** Argument pIdxInfo is already populated with all constraints that may
** be used by the virtual table identified by pBuilder->pNew->iTab. This
** function marks a subset of those constraints usable, invokes the
** xBestIndex method and adds the returned plan to pBuilder.
**

sqlite3.c  view on Meta::CPAN

    assert( pWInfo->nLevel>0 );
  }
  return notReady;
}

/*
** Check to see if there are any SEARCH loops that might benefit from
** using a Bloom filter.  Consider a Bloom filter if:
**
**   (1)  The SEARCH happens more than N times where N is the number
**        of rows in the table that is being considered for the Bloom
**        filter.
**   (2)  Some searches are expected to find zero rows.  (This is determined
**        by the WHERE_SELFCULL flag on the term.)
**   (3)  Bloom-filter processing is not disabled.  (Checked by the
**        caller.)
**   (4)  The size of the table being searched is known by ANALYZE.
**
** This block of code merely checks to see if a Bloom filter would be
** appropriate, and if so sets the WHERE_BLOOMFILTER flag on the
** WhereLoop.  The implementation of the Bloom filter comes further
** down where the code for each WhereLoop is generated.
*/
static SQLITE_NOINLINE void whereCheckIfBloomFilterIsUseful(
  const WhereInfo *pWInfo
){
  int i;
  LogEst nSearch = 0;

  assert( pWInfo->nLevel>=2 );
  assert( OptimizationEnabled(pWInfo->pParse->db, SQLITE_BloomFilter) );
  for(i=0; i<pWInfo->nLevel; i++){
    WhereLoop *pLoop = pWInfo->a[i].pWLoop;
    const unsigned int reqFlags = (WHERE_SELFCULL|WHERE_COLUMN_EQ);
    SrcItem *pItem = &pWInfo->pTabList->a[pLoop->iTab];
    Table *pTab = pItem->pSTab;
    if( (pTab->tabFlags & TF_HasStat1)==0 ) break;
    pTab->tabFlags |= TF_MaybeReanalyze;
    if( i>=1
     && (pLoop->wsFlags & reqFlags)==reqFlags
     /* vvvvvv--- Always the case if WHERE_COLUMN_EQ is defined */
     && ALWAYS((pLoop->wsFlags & (WHERE_IPK|WHERE_INDEXED))!=0)
    ){
      if( nSearch > pTab->nRowLogEst ){
        testcase( pItem->fg.jointype & JT_LEFT );
        pLoop->wsFlags |= WHERE_BLOOMFILTER;
        pLoop->wsFlags &= ~WHERE_IDX_ONLY;
        WHERETRACE(0xffffffff, (
           "-> use Bloom-filter on loop %c because there are ~%.1e "
           "lookups into %s which has only ~%.1e rows\n",
           pLoop->cId, (double)sqlite3LogEstToInt(nSearch), pTab->zName,
           (double)sqlite3LogEstToInt(pTab->nRowLogEst)));
      }
    }
    nSearch += pLoop->nOut;
  }
}

/*
** The index pIdx is used by a query and contains one or more expressions.
** In other words pIdx is an index on an expression.  iIdxCur is the cursor
** number for the index and iDataCur is the cursor number for the corresponding
** table.
**
** This routine adds IndexedExpr entries to the Parse->pIdxEpr field for
** each of the expressions in the index so that the expression code generator
** will know to replace occurrences of the indexed expression with
** references to the corresponding column of the index.
*/
static SQLITE_NOINLINE void whereAddIndexedExpr(
  Parse *pParse,     /* Add IndexedExpr entries to pParse->pIdxEpr */
  Index *pIdx,       /* The index-on-expression that contains the expressions */
  int iIdxCur,       /* Cursor number for pIdx */
  SrcItem *pTabItem  /* The FROM clause entry for the table */
){
  int i;
  IndexedExpr *p;
  Table *pTab;
  assert( pIdx->bHasExpr );
  pTab = pIdx->pTable;
  for(i=0; i<pIdx->nColumn; i++){
    Expr *pExpr;
    int j = pIdx->aiColumn[i];
    if( j==XN_EXPR ){
      pExpr = pIdx->aColExpr->a[i].pExpr;
    }else if( j>=0 && (pTab->aCol[j].colFlags & COLFLAG_VIRTUAL)!=0 ){
      pExpr = sqlite3ColumnExpr(pTab, &pTab->aCol[j]);
    }else{
      continue;
    }
    if( sqlite3ExprIsConstant(0,pExpr) ) continue;
    p = sqlite3DbMallocRaw(pParse->db,  sizeof(IndexedExpr));
    if( p==0 ) break;
    p->pIENext = pParse->pIdxEpr;
#ifdef WHERETRACE_ENABLED
    if( sqlite3WhereTrace & 0x200 ){
      sqlite3DebugPrintf("New pParse->pIdxEpr term {%d,%d}\n", iIdxCur, i);
      if( sqlite3WhereTrace & 0x5000 ) sqlite3ShowExpr(pExpr);
    }
#endif
    p->pExpr = sqlite3ExprDup(pParse->db, pExpr, 0);
    p->iDataCur = pTabItem->iCursor;
    p->iIdxCur = iIdxCur;
    p->iIdxCol = i;
    p->bMaybeNullRow = (pTabItem->fg.jointype & (JT_LEFT|JT_LTORJ|JT_RIGHT))!=0;
    if( sqlite3IndexAffinityStr(pParse->db, pIdx) ){
      p->aff = pIdx->zColAff[i];
    }
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
    p->zIdxName = pIdx->zName;
#endif
    pParse->pIdxEpr = p;
    if( p->pIENext==0 ){
      void *pArg = (void*)&pParse->pIdxEpr;
      sqlite3ParserAddCleanup(pParse, whereIndexedExprCleanup, pArg);
    }
  }
}

/*
** Set the reverse-scan order mask to one for all tables in the query
** with the exception of MATERIALIZED common table expressions that have
** their own internal ORDER BY clauses.
**
** This implements the PRAGMA reverse_unordered_selects=ON setting.
** (Also SQLITE_DBCONFIG_REVERSE_SCANORDER).
*/
static SQLITE_NOINLINE void whereReverseScanOrder(WhereInfo *pWInfo){
  int ii;
  for(ii=0; ii<pWInfo->pTabList->nSrc; ii++){
    SrcItem *pItem = &pWInfo->pTabList->a[ii];
    if( !pItem->fg.isCte
     || pItem->u2.pCteUse->eM10d!=M10d_Yes
     || NEVER(pItem->fg.isSubquery==0)
     || pItem->u4.pSubq->pSelect->pOrderBy==0
    ){
      pWInfo->revMask |= MASKBIT(ii);
    }
  }
}

/*
** Generate the beginning of the loop used for WHERE clause processing.
** The return value is a pointer to an opaque structure that contains
** information needed to terminate the loop.  Later, the calling routine
** should invoke sqlite3WhereEnd() with the return value of this function
** in order to complete the WHERE clause processing.
**
** If an error occurs, this routine returns NULL.
**
** The basic idea is to do a nested loop, one loop for each table in
** the FROM clause of a select.  (INSERT and UPDATE statements are the
** same as a SELECT with only a single table in the FROM clause.)  For
** example, if the SQL is this:
**
**       SELECT * FROM t1, t2, t3 WHERE ...;
**
** Then the code generated is conceptually like the following:
**
**      foreach row1 in t1 do       \    Code generated
**        foreach row2 in t2 do      |-- by sqlite3WhereBegin()
**          foreach row3 in t3 do   /
**            ...
**          end                     \    Code generated
**        end                        |-- by sqlite3WhereEnd()
**      end                         /
**
** Note that the loops might not be nested in the order in which they
** appear in the FROM clause if a different order is better able to make
** use of indices.  Note also that when the IN operator appears in
** the WHERE clause, it might result in additional nested loops for
** scanning through all values on the right-hand side of the IN.
**
** There are Btree cursors associated with each table.  t1 uses cursor
** number pTabList->a[0].iCursor.  t2 uses the cursor pTabList->a[1].iCursor.
** And so forth.  This routine generates code to open those VDBE cursors
** and sqlite3WhereEnd() generates the code to close them.
**
** The code that sqlite3WhereBegin() generates leaves the cursors named
** in pTabList pointing at their appropriate entries.  The [...] code
** can use OP_Column and OP_Rowid opcodes on these cursors to extract
** data from the various tables of the loop.
**
** If the WHERE clause is empty, the foreach loops must each scan their
** entire tables.  Thus a three-way join is an O(N^3) operation.  But if
** the tables have indices and there are terms in the WHERE clause that
** refer to those indices, a complete table scan can be avoided and the
** code will run much faster.  Most of the work of this routine is checking
** to see if there are indices that can be used to speed up the loop.
**
** Terms of the WHERE clause are also used to limit which rows actually
** make it to the "..." in the middle of the loop.  After each "foreach",
** terms of the WHERE clause that use only terms in that loop and outer
** loops are evaluated and if false a jump is made around all subsequent
** inner loops (or around the "..." if the test occurs within the inner-
** most loop)
**
** OUTER JOINS
**
** An outer join of tables t1 and t2 is conceptually coded as follows:
**
**    foreach row1 in t1 do
**      flag = 0
**      foreach row2 in t2 do
**        start:
**          ...
**          flag = 1
**      end
**      if flag==0 then
**        move the row2 cursor to a null row
**        goto start
**      fi
**    end
**
** ORDER BY CLAUSE PROCESSING
**
** pOrderBy is a pointer to the ORDER BY clause (or the GROUP BY clause
** if the WHERE_GROUPBY flag is set in wctrlFlags) of a SELECT statement
** if there is one.  If there is no ORDER BY clause or if this routine
** is called from an UPDATE or DELETE statement, then pOrderBy is NULL.
**
** The iIdxCur parameter is the cursor number of an index.  If
** WHERE_OR_SUBCLAUSE is set, iIdxCur is the cursor number of an index
** to use for OR clause processing.  The WHERE clause should use this
** specific cursor.  If WHERE_ONEPASS_DESIRED is set, then iIdxCur is
** the first cursor in an array of cursors for all indices.  iIdxCur should
** be used to compute the appropriate cursor depending on which index is
** used.
*/
SQLITE_PRIVATE WhereInfo *sqlite3WhereBegin(
  Parse *pParse,          /* The parser context */
  SrcList *pTabList,      /* FROM clause: A list of all tables to be scanned */
  Expr *pWhere,           /* The WHERE clause */
  ExprList *pOrderBy,     /* An ORDER BY (or GROUP BY) clause, or NULL */
  ExprList *pResultSet,   /* Query result set.  Req'd for DISTINCT */
  Select *pSelect,        /* The entire SELECT statement */
  u16 wctrlFlags,         /* The WHERE_* flags defined in sqliteInt.h */
  int iAuxArg             /* If WHERE_OR_SUBCLAUSE is set, index cursor number
                          ** If WHERE_USE_LIMIT, then the limit amount */
){
  int nByteWInfo;            /* Num. bytes allocated for WhereInfo struct */
  int nTabList;              /* Number of elements in pTabList */
  WhereInfo *pWInfo;         /* Will become the return value of this function */
  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
  Bitmask notReady;          /* Cursors that are not yet positioned */
  WhereLoopBuilder sWLB;     /* The WhereLoop builder */
  WhereMaskSet *pMaskSet;    /* The expression mask set */
  WhereLevel *pLevel;        /* A single level in pWInfo->a[] */
  WhereLoop *pLoop;          /* Pointer to a single WhereLoop object */
  int ii;                    /* Loop counter */
  sqlite3 *db;               /* Database connection */
  int rc;                    /* Return code */
  u8 bFordelete = 0;         /* OPFLAG_FORDELETE or zero, as appropriate */

  assert( (wctrlFlags & WHERE_ONEPASS_MULTIROW)==0 || (
        (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0
     && (wctrlFlags & WHERE_OR_SUBCLAUSE)==0
  ));

  /* Only one of WHERE_OR_SUBCLAUSE or WHERE_USE_LIMIT */
  assert( (wctrlFlags & WHERE_OR_SUBCLAUSE)==0
            || (wctrlFlags & WHERE_USE_LIMIT)==0 );

  /* Variable initialization */
  db = pParse->db;
  memset(&sWLB, 0, sizeof(sWLB));

  /* An ORDER/GROUP BY clause of more than 63 terms cannot be optimized */
  testcase( pOrderBy && pOrderBy->nExpr==BMS-1 );
  if( pOrderBy && pOrderBy->nExpr>=BMS ){
    pOrderBy = 0;
    wctrlFlags &= ~WHERE_WANT_DISTINCT;
    wctrlFlags |= WHERE_KEEP_ALL_JOINS; /* Disable omit-noop-join opt */
  }

  /* The number of tables in the FROM clause is limited by the number of
  ** bits in a Bitmask
  */
  testcase( pTabList->nSrc==BMS );
  if( pTabList->nSrc>BMS ){
    sqlite3ErrorMsg(pParse, "at most %d tables in a join", BMS);
    return 0;
  }

  /* This function normally generates a nested loop for all tables in
  ** pTabList.  But if the WHERE_OR_SUBCLAUSE flag is set, then we should
  ** only generate code for the first table in pTabList and assume that
  ** any cursors associated with subsequent tables are uninitialized.
  */
  nTabList = (wctrlFlags & WHERE_OR_SUBCLAUSE) ? 1 : pTabList->nSrc;

  /* Allocate and initialize the WhereInfo structure that will become the
  ** return value. A single allocation is used to store the WhereInfo
  ** struct, the contents of WhereInfo.a[], the WhereClause structure
  ** and the WhereMaskSet structure. Since WhereClause contains an 8-byte
  ** field (type Bitmask) it must be aligned on an 8-byte boundary on
  ** some architectures. Hence the ROUND8() below.
  */
  nByteWInfo = SZ_WHEREINFO(nTabList);
  pWInfo = sqlite3DbMallocRawNN(db, nByteWInfo + sizeof(WhereLoop));
  if( db->mallocFailed ){
    sqlite3DbFree(db, pWInfo);
    pWInfo = 0;
    goto whereBeginError;
  }
  pWInfo->pParse = pParse;
  pWInfo->pTabList = pTabList;
  pWInfo->pOrderBy = pOrderBy;
#if WHERETRACE_ENABLED
  pWInfo->pWhere = pWhere;
#endif
  pWInfo->pResultSet = pResultSet;
  pWInfo->aiCurOnePass[0] = pWInfo->aiCurOnePass[1] = -1;
  pWInfo->nLevel = nTabList;
  pWInfo->iBreak = pWInfo->iContinue = sqlite3VdbeMakeLabel(pParse);
  pWInfo->wctrlFlags = wctrlFlags;
  pWInfo->iLimit = iAuxArg;
  pWInfo->savedNQueryLoop = pParse->nQueryLoop;
  pWInfo->pSelect = pSelect;
  memset(&pWInfo->nOBSat, 0,
         offsetof(WhereInfo,sWC) - offsetof(WhereInfo,nOBSat));
  memset(&pWInfo->a[0], 0, sizeof(WhereLoop)+nTabList*sizeof(WhereLevel));
  assert( pWInfo->eOnePass==ONEPASS_OFF );  /* ONEPASS defaults to OFF */
  pMaskSet = &pWInfo->sMaskSet;
  pMaskSet->n = 0;
  pMaskSet->ix[0] = -99; /* Initialize ix[0] to a value that can never be
                         ** a valid cursor number, to avoid an initial
                         ** test for pMaskSet->n==0 in sqlite3WhereGetMask() */
  sWLB.pWInfo = pWInfo;
  sWLB.pWC = &pWInfo->sWC;
  sWLB.pNew = (WhereLoop*)(((char*)pWInfo)+nByteWInfo);
  assert( EIGHT_BYTE_ALIGNMENT(sWLB.pNew) );
  whereLoopInit(sWLB.pNew);
#ifdef SQLITE_DEBUG
  sWLB.pNew->cId = '*';
#endif

  /* Split the WHERE clause into separate subexpressions where each
  ** subexpression is separated by an AND operator.
  */
  sqlite3WhereClauseInit(&pWInfo->sWC, pWInfo);
  sqlite3WhereSplit(&pWInfo->sWC, pWhere, TK_AND);

  /* Special case: No FROM clause
  */
  if( nTabList==0 ){
    if( pOrderBy ) pWInfo->nOBSat = pOrderBy->nExpr;
    if( (wctrlFlags & WHERE_WANT_DISTINCT)!=0
     && OptimizationEnabled(db, SQLITE_DistinctOpt)
    ){
      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
    }
    if( ALWAYS(pWInfo->pSelect)
     && (pWInfo->pSelect->selFlags & SF_MultiValue)==0
    ){
      ExplainQueryPlan((pParse, 0, "SCAN CONSTANT ROW"));
    }
  }else{
    /* Assign a bit from the bitmask to every term in the FROM clause.
    **
    ** The N-th term of the FROM clause is assigned a bitmask of 1<<N.
    **
    ** The rule of the previous sentence ensures that if X is the bitmask for
    ** a table T, then X-1 is the bitmask for all other tables to the left of T.
    ** Knowing the bitmask for all tables to the left of a left join is
    ** important.  Ticket #3015.
    **
    ** Note that bitmasks are created for all pTabList->nSrc tables in
    ** pTabList, not just the first nTabList tables.  nTabList is normally
    ** equal to pTabList->nSrc but might be shortened to 1 if the
    ** WHERE_OR_SUBCLAUSE flag is set.
    */
    ii = 0;
    do{
      createMask(pMaskSet, pTabList->a[ii].iCursor);
      sqlite3WhereTabFuncArgs(pParse, &pTabList->a[ii], &pWInfo->sWC);
    }while( (++ii)<pTabList->nSrc );
  #ifdef SQLITE_DEBUG
    {
      Bitmask mx = 0;
      for(ii=0; ii<pTabList->nSrc; ii++){
        Bitmask m = sqlite3WhereGetMask(pMaskSet, pTabList->a[ii].iCursor);
        assert( m>=mx );
        mx = m;
      }
    }
  #endif

sqlite3.c  view on Meta::CPAN

          sqlite3VdbeAddOp3(v, OP_Column, pLevel->iIdxCur, j, r1+j);
        }
        pParse->nMem += n+1;
        op = pLevel->op==OP_Prev ? OP_SeekLT : OP_SeekGT;
        addrSeek = sqlite3VdbeAddOp4Int(v, op, pLevel->iIdxCur, 0, r1, n);
        VdbeCoverageIf(v, op==OP_SeekLT);
        VdbeCoverageIf(v, op==OP_SeekGT);
        sqlite3VdbeAddOp2(v, OP_Goto, 1, pLevel->p2);
      }
#endif /* SQLITE_DISABLE_SKIPAHEAD_DISTINCT */
      if( pTabList->a[pLevel->iFrom].fg.fromExists && i==pWInfo->nLevel-1 ){
        /* If the EXISTS-to-JOIN optimization was applied, then the EXISTS
        ** loop(s) will be the inner-most loops of the join. There might be
        ** multiple EXISTS loops, but they will all be nested, and the join
        ** order will not have been changed by the query planner.  If the
        ** inner-most EXISTS loop sees a single successful row, it should
        ** break out of *all* EXISTS loops.  But only the inner-most of the
        ** nested EXISTS loops should do this breakout. */
        int nOuter = 0; /* Nr of outer EXISTS that this one is nested within */
        while( nOuter<i ){
          if( !pTabList->a[pLevel[-nOuter-1].iFrom].fg.fromExists ) break;
          nOuter++;
        }
        testcase( nOuter>0 );
        sqlite3VdbeAddOp2(v, OP_Goto, 0, pLevel[-nOuter].addrBrk);
        VdbeComment((v, "EXISTS break"));
      }
      /* The common case: Advance to the next row */
      if( pLevel->addrCont ) sqlite3VdbeResolveLabel(v, pLevel->addrCont);
      sqlite3VdbeAddOp3(v, pLevel->op, pLevel->p1, pLevel->p2, pLevel->p3);
      sqlite3VdbeChangeP5(v, pLevel->p5);
      VdbeCoverage(v);
      VdbeCoverageIf(v, pLevel->op==OP_Next);
      VdbeCoverageIf(v, pLevel->op==OP_Prev);
      VdbeCoverageIf(v, pLevel->op==OP_VNext);
      if( pLevel->regBignull ){
        sqlite3VdbeResolveLabel(v, pLevel->addrBignull);
        sqlite3VdbeAddOp2(v, OP_DecrJumpZero, pLevel->regBignull, pLevel->p2-1);
        VdbeCoverage(v);
      }
#ifndef SQLITE_DISABLE_SKIPAHEAD_DISTINCT
      if( addrSeek ) sqlite3VdbeJumpHere(v, addrSeek);
#endif
    }else if( pLevel->addrCont ){
      sqlite3VdbeResolveLabel(v, pLevel->addrCont);
    }
    if( (pLoop->wsFlags & WHERE_IN_ABLE)!=0 && pLevel->u.in.nIn>0 ){
      struct InLoop *pIn;
      int j;
      sqlite3VdbeResolveLabel(v, pLevel->addrNxt);
      for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
        assert( sqlite3VdbeGetOp(v, pIn->addrInTop+1)->opcode==OP_IsNull
                 || pParse->db->mallocFailed );
        sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
        if( pIn->eEndLoopOp!=OP_Noop ){
          if( pIn->nPrefix ){
            int bEarlyOut =
                (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0
                 && (pLoop->wsFlags & WHERE_IN_EARLYOUT)!=0;
            if( pLevel->iLeftJoin ){
              /* For LEFT JOIN queries, cursor pIn->iCur may not have been
              ** opened yet. This occurs for WHERE clauses such as
              ** "a = ? AND b IN (...)", where the index is on (a, b). If
              ** the RHS of the (a=?) is NULL, then the "b IN (...)" may
              ** never have been coded, but the body of the loop run to
              ** return the null-row. So, if the cursor is not open yet,
              ** jump over the OP_Next or OP_Prev instruction about to
              ** be coded.  */
              sqlite3VdbeAddOp2(v, OP_IfNotOpen, pIn->iCur,
                  sqlite3VdbeCurrentAddr(v) + 2 + bEarlyOut);
              VdbeCoverage(v);
            }
            if( bEarlyOut ){
              sqlite3VdbeAddOp4Int(v, OP_IfNoHope, pLevel->iIdxCur,
                  sqlite3VdbeCurrentAddr(v)+2,
                  pIn->iBase, pIn->nPrefix);
              VdbeCoverage(v);
              /* Retarget the OP_IsNull against the left operand of IN so
              ** it jumps past the OP_IfNoHope.  This is because the
              ** OP_IsNull also bypasses the OP_Affinity opcode that is
              ** required by OP_IfNoHope. */
              sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
            }
          }
          sqlite3VdbeAddOp2(v, pIn->eEndLoopOp, pIn->iCur, pIn->addrInTop);
          VdbeCoverage(v);
          VdbeCoverageIf(v, pIn->eEndLoopOp==OP_Prev);
          VdbeCoverageIf(v, pIn->eEndLoopOp==OP_Next);
        }
        sqlite3VdbeJumpHere(v, pIn->addrInTop-1);
      }
    }
    sqlite3VdbeResolveLabel(v, pLevel->addrBrk);
    if( pLevel->pRJ ){
      sqlite3VdbeAddOp3(v, OP_Return, pLevel->pRJ->regReturn, 0, 1);
      VdbeCoverage(v);
    }
    if( pLevel->addrSkip ){
      sqlite3VdbeGoto(v, pLevel->addrSkip);
      VdbeComment((v, "next skip-scan on %s", pLoop->u.btree.pIndex->zName));
      sqlite3VdbeJumpHere(v, pLevel->addrSkip);
      sqlite3VdbeJumpHere(v, pLevel->addrSkip-2);
    }
#ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS
    if( pLevel->addrLikeRep ){
      sqlite3VdbeAddOp2(v, OP_DecrJumpZero, (int)(pLevel->iLikeRepCntr>>1),
                        pLevel->addrLikeRep);
      VdbeCoverage(v);
    }
#endif
    if( pLevel->iLeftJoin ){
      int ws = pLoop->wsFlags;
      addr = sqlite3VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin); VdbeCoverage(v);
      assert( (ws & WHERE_IDX_ONLY)==0 || (ws & WHERE_INDEXED)!=0 );
      if( (ws & WHERE_IDX_ONLY)==0 ){
        SrcItem *pSrc = &pTabList->a[pLevel->iFrom];
        assert( pLevel->iTabCur==pSrc->iCursor );
        if( pSrc->fg.viaCoroutine ){
          int m, n;
          assert( pSrc->fg.isSubquery );
          n = pSrc->u4.pSubq->regResult;
          assert( pSrc->pSTab!=0 );
          m = pSrc->pSTab->nCol;
          sqlite3VdbeAddOp3(v, OP_Null, 0, n, n+m-1);
        }
        sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iTabCur);

sqlite3.c  view on Meta::CPAN

      continue;
    }

    /* For a co-routine, change all OP_Column references to the table of
    ** the co-routine into OP_Copy of result contained in a register.
    ** OP_Rowid becomes OP_Null.
    */
    if( pTabItem->fg.viaCoroutine ){
      testcase( pParse->db->mallocFailed );
      assert( pTabItem->fg.isSubquery );
      assert( pTabItem->u4.pSubq->regResult>=0 );
      translateColumnToCopy(pParse, pLevel->addrBody, pLevel->iTabCur,
                            pTabItem->u4.pSubq->regResult, 0);
      continue;
    }

    /* If this scan uses an index, make VDBE code substitutions to read data
    ** from the index instead of from the table where possible.  In some cases
    ** this optimization prevents the table from ever being read, which can
    ** yield a significant performance boost.
    **
    ** Calls to the code generator in between sqlite3WhereBegin and
    ** sqlite3WhereEnd will have created code that references the table
    ** directly.  This loop scans all that code looking for opcodes
    ** that reference the table and converts them into opcodes that
    ** reference the index.
    */
    if( pLoop->wsFlags & (WHERE_INDEXED|WHERE_IDX_ONLY) ){
      pIdx = pLoop->u.btree.pIndex;
    }else if( pLoop->wsFlags & WHERE_MULTI_OR ){
      pIdx = pLevel->u.pCoveringIdx;
    }
    if( pIdx
     && !db->mallocFailed
    ){
      if( pWInfo->eOnePass==ONEPASS_OFF || !HasRowid(pIdx->pTable) ){
        last = iEnd;
      }else{
        last = pWInfo->iEndWhere;
      }
      if( pIdx->bHasExpr ){
        IndexedExpr *p = pParse->pIdxEpr;
        while( p ){
          if( p->iIdxCur==pLevel->iIdxCur ){
#ifdef WHERETRACE_ENABLED
            if( sqlite3WhereTrace & 0x200 ){
              sqlite3DebugPrintf("Disable pParse->pIdxEpr term {%d,%d}\n",
                                  p->iIdxCur, p->iIdxCol);
              if( sqlite3WhereTrace & 0x5000 ) sqlite3ShowExpr(p->pExpr);
            }
#endif
            p->iDataCur = -1;
            p->iIdxCur = -1;
          }
          p = p->pIENext;
        }
      }
      k = pLevel->addrBody + 1;
#ifdef SQLITE_DEBUG
      if( db->flags & SQLITE_VdbeAddopTrace ){
        printf("TRANSLATE cursor %d->%d in opcode range %d..%d\n",
                pLevel->iTabCur, pLevel->iIdxCur, k, last-1);
      }
      /* Proof that the "+1" on the k value above is safe */
      pOp = sqlite3VdbeGetOp(v, k - 1);
      assert( pOp->opcode!=OP_Column || pOp->p1!=pLevel->iTabCur );
      assert( pOp->opcode!=OP_Rowid  || pOp->p1!=pLevel->iTabCur );
      assert( pOp->opcode!=OP_IfNullRow || pOp->p1!=pLevel->iTabCur );
#endif
      pOp = sqlite3VdbeGetOp(v, k);
      pLastOp = pOp + (last - k);
      assert( pOp<=pLastOp );
      do{
        if( pOp->p1!=pLevel->iTabCur ){
          /* no-op */
        }else if( pOp->opcode==OP_Column
#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
         || pOp->opcode==OP_Offset
#endif
        ){
          int x = pOp->p2;
          assert( pIdx->pTable==pTab );
#ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC
          if( pOp->opcode==OP_Offset ){
            /* Do not need to translate the column number */
          }else
#endif
          if( !HasRowid(pTab) ){
            Index *pPk = sqlite3PrimaryKeyIndex(pTab);
            x = pPk->aiColumn[x];
            assert( x>=0 );
          }else{
            testcase( x!=sqlite3StorageColumnToTable(pTab,x) );
            x = sqlite3StorageColumnToTable(pTab,x);
          }
          x = sqlite3TableColumnToIndex(pIdx, x);
          if( x>=0 ){
            pOp->p2 = x;
            pOp->p1 = pLevel->iIdxCur;
            OpcodeRewriteTrace(db, k, pOp);
          }else if( pLoop->wsFlags & (WHERE_IDX_ONLY|WHERE_EXPRIDX) ){
            if( pLoop->wsFlags & WHERE_IDX_ONLY ){
              /* An error. pLoop is supposed to be a covering index loop,
              ** and yet the VM code refers to a column of the table that
              ** is not part of the index.  */
              sqlite3ErrorMsg(pParse, "internal query planner error");
              pParse->rc = SQLITE_INTERNAL;
            }else{
              /* The WHERE_EXPRIDX flag is set by the planner when it is likely
              ** that pLoop is a covering index loop, but it is not possible
              ** to be 100% sure. In this case, any OP_Explain opcode
              ** corresponding to this loop describes the index as a "COVERING
              ** INDEX". But, pOp proves that pLoop is not actually a covering
              ** index loop. So clear the WHERE_EXPRIDX flag and rewrite the
              ** text that accompanies the OP_Explain opcode, if any.  */
              pLoop->wsFlags &= ~WHERE_EXPRIDX;
              sqlite3WhereAddExplainText(pParse,
                  pLevel->addrBody-1,
                  pTabList,
                  pLevel,
                  pWInfo->wctrlFlags

sqlite3.c  view on Meta::CPAN

** at the top of this file.
*/
SQLITE_PRIVATE int sqlite3WindowRewrite(Parse *pParse, Select *p){
  int rc = SQLITE_OK;
  if( p->pWin
   && p->pPrior==0
   && ALWAYS((p->selFlags & SF_WinRewrite)==0)
   && ALWAYS(!IN_RENAME_OBJECT)
  ){
    Vdbe *v = sqlite3GetVdbe(pParse);
    sqlite3 *db = pParse->db;
    Select *pSub = 0;             /* The subquery */
    SrcList *pSrc = p->pSrc;
    Expr *pWhere = p->pWhere;
    ExprList *pGroupBy = p->pGroupBy;
    Expr *pHaving = p->pHaving;
    ExprList *pSort = 0;

    ExprList *pSublist = 0;       /* Expression list for sub-query */
    Window *pMWin = p->pWin;      /* Main window object */
    Window *pWin;                 /* Window object iterator */
    Table *pTab;
    Walker w;

    u32 selFlags = p->selFlags;

    pTab = sqlite3DbMallocZero(db, sizeof(Table));
    if( pTab==0 ){
      return sqlite3ErrorToParser(db, SQLITE_NOMEM);
    }
    sqlite3AggInfoPersistWalkerInit(&w, pParse);
    sqlite3WalkSelect(&w, p);
    if( (p->selFlags & SF_Aggregate)==0 ){
      w.xExprCallback = disallowAggregatesInOrderByCb;
      w.xSelectCallback = 0;
      sqlite3WalkExprList(&w, p->pOrderBy);
    }

    p->pSrc = 0;
    p->pWhere = 0;
    p->pGroupBy = 0;
    p->pHaving = 0;
    p->selFlags &= ~(u32)SF_Aggregate;
    p->selFlags |= SF_WinRewrite;

    /* Create the ORDER BY clause for the sub-select. This is the concatenation
    ** of the window PARTITION and ORDER BY clauses. Then, if this makes it
    ** redundant, remove the ORDER BY from the parent SELECT.  */
    pSort = exprListAppendList(pParse, 0, pMWin->pPartition, 1);
    pSort = exprListAppendList(pParse, pSort, pMWin->pOrderBy, 1);
    if( pSort && p->pOrderBy && p->pOrderBy->nExpr<=pSort->nExpr ){
      int nSave = pSort->nExpr;
      pSort->nExpr = p->pOrderBy->nExpr;
      if( sqlite3ExprListCompare(pSort, p->pOrderBy, -1)==0 ){
        sqlite3ExprListDelete(db, p->pOrderBy);
        p->pOrderBy = 0;
      }
      pSort->nExpr = nSave;
    }

    /* Assign a cursor number for the ephemeral table used to buffer rows.
    ** The OpenEphemeral instruction is coded later, after it is known how
    ** many columns the table will have.  */
    pMWin->iEphCsr = pParse->nTab++;
    pParse->nTab += 3;

    selectWindowRewriteEList(pParse, pMWin, pSrc, p->pEList, pTab, &pSublist);
    selectWindowRewriteEList(pParse, pMWin, pSrc, p->pOrderBy, pTab, &pSublist);
    pMWin->nBufferCol = (pSublist ? pSublist->nExpr : 0);

    /* Append the PARTITION BY and ORDER BY expressions to the to the
    ** sub-select expression list. They are required to figure out where
    ** boundaries for partitions and sets of peer rows lie.  */
    pSublist = exprListAppendList(pParse, pSublist, pMWin->pPartition, 0);
    pSublist = exprListAppendList(pParse, pSublist, pMWin->pOrderBy, 0);

    /* Append the arguments passed to each window function to the
    ** sub-select expression list. Also allocate two registers for each
    ** window function - one for the accumulator, another for interim
    ** results.  */
    for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
      ExprList *pArgs;
      assert( ExprUseXList(pWin->pOwner) );
      assert( pWin->pWFunc!=0 );
      pArgs = pWin->pOwner->x.pList;
      if( pWin->pWFunc->funcFlags & SQLITE_SUBTYPE ){
        selectWindowRewriteEList(pParse, pMWin, pSrc, pArgs, pTab, &pSublist);
        pWin->iArgCol = (pSublist ? pSublist->nExpr : 0);
        pWin->bExprArgs = 1;
      }else{
        pWin->iArgCol = (pSublist ? pSublist->nExpr : 0);
        pSublist = exprListAppendList(pParse, pSublist, pArgs, 0);
      }
      if( pWin->pFilter ){
        Expr *pFilter = sqlite3ExprDup(db, pWin->pFilter, 0);
        pSublist = sqlite3ExprListAppend(pParse, pSublist, pFilter);
      }
      pWin->regAccum = ++pParse->nMem;
      pWin->regResult = ++pParse->nMem;
      sqlite3VdbeAddOp2(v, OP_Null, 0, pWin->regAccum);
    }

    /* If there is no ORDER BY or PARTITION BY clause, and the window
    ** function accepts zero arguments, and there are no other columns
    ** selected (e.g. "SELECT row_number() OVER () FROM t1"), it is possible
    ** that pSublist is still NULL here. Add a constant expression here to
    ** keep everything legal in this case.
    */
    if( pSublist==0 ){
      pSublist = sqlite3ExprListAppend(pParse, 0,
        sqlite3Expr(db, TK_INTEGER, "0")
      );
    }

    pSub = sqlite3SelectNew(
        pParse, pSublist, pSrc, pWhere, pGroupBy, pHaving, pSort, 0, 0
    );
    TREETRACE(0x40,pParse,pSub,
       ("New window-function subquery in FROM clause of (%u/%p)\n",
       p->selId, p));
    p->pSrc = sqlite3SrcListAppend(pParse, 0, 0, 0);

sqlite3.c  view on Meta::CPAN

/*
** Possibly link window pWin into the list at pSel->pWin (window functions
** to be processed as part of SELECT statement pSel). The window is linked
** in if either (a) there are no other windows already linked to this
** SELECT, or (b) the windows already linked use a compatible window frame.
*/
SQLITE_PRIVATE void sqlite3WindowLink(Select *pSel, Window *pWin){
  if( pSel ){
    if( 0==pSel->pWin || 0==sqlite3WindowCompare(0, pSel->pWin, pWin, 0) ){
      pWin->pNextWin = pSel->pWin;
      if( pSel->pWin ){
        pSel->pWin->ppThis = &pWin->pNextWin;
      }
      pSel->pWin = pWin;
      pWin->ppThis = &pSel->pWin;
    }else{
      if( sqlite3ExprListCompare(pWin->pPartition, pSel->pWin->pPartition,-1) ){
        pSel->selFlags |= SF_MultiPart;
      }
    }
  }
}

/*
** Return 0 if the two window objects are identical, 1 if they are
** different, or 2 if it cannot be determined if the objects are identical
** or not. Identical window objects can be processed in a single scan.
*/
SQLITE_PRIVATE int sqlite3WindowCompare(
  const Parse *pParse,
  const Window *p1,
  const Window *p2,
  int bFilter
){
  int res;
  if( NEVER(p1==0) || NEVER(p2==0) ) return 1;
  if( p1->eFrmType!=p2->eFrmType ) return 1;
  if( p1->eStart!=p2->eStart ) return 1;
  if( p1->eEnd!=p2->eEnd ) return 1;
  if( p1->eExclude!=p2->eExclude ) return 1;
  if( sqlite3ExprCompare(pParse, p1->pStart, p2->pStart, -1) ) return 1;
  if( sqlite3ExprCompare(pParse, p1->pEnd, p2->pEnd, -1) ) return 1;
  if( (res = sqlite3ExprListCompare(p1->pPartition, p2->pPartition, -1)) ){
    return res;
  }
  if( (res = sqlite3ExprListCompare(p1->pOrderBy, p2->pOrderBy, -1)) ){
    return res;
  }
  if( bFilter ){
    if( (res = sqlite3ExprCompare(pParse, p1->pFilter, p2->pFilter, -1)) ){
      return res;
    }
  }
  return 0;
}


/*
** This is called by code in select.c before it calls sqlite3WhereBegin()
** to begin iterating through the sub-query results. It is used to allocate
** and initialize registers and cursors used by sqlite3WindowCodeStep().
*/
SQLITE_PRIVATE void sqlite3WindowCodeInit(Parse *pParse, Select *pSelect){
  Window *pWin;
  int nEphExpr;
  Window *pMWin;
  Vdbe *v;

  assert( pSelect->pSrc->a[0].fg.isSubquery );
  nEphExpr = pSelect->pSrc->a[0].u4.pSubq->pSelect->pEList->nExpr;
  pMWin = pSelect->pWin;
  v = sqlite3GetVdbe(pParse);

  sqlite3VdbeAddOp2(v, OP_OpenEphemeral, pMWin->iEphCsr, nEphExpr);
  sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+1, pMWin->iEphCsr);
  sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+2, pMWin->iEphCsr);
  sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->iEphCsr+3, pMWin->iEphCsr);

  /* Allocate registers to use for PARTITION BY values, if any. Initialize
  ** said registers to NULL.  */
  if( pMWin->pPartition ){
    int nExpr = pMWin->pPartition->nExpr;
    pMWin->regPart = pParse->nMem+1;
    pParse->nMem += nExpr;
    sqlite3VdbeAddOp3(v, OP_Null, 0, pMWin->regPart, pMWin->regPart+nExpr-1);
  }

  pMWin->regOne = ++pParse->nMem;
  sqlite3VdbeAddOp2(v, OP_Integer, 1, pMWin->regOne);

  if( pMWin->eExclude ){
    pMWin->regStartRowid = ++pParse->nMem;
    pMWin->regEndRowid = ++pParse->nMem;
    pMWin->csrApp = pParse->nTab++;
    sqlite3VdbeAddOp2(v, OP_Integer, 1, pMWin->regStartRowid);
    sqlite3VdbeAddOp2(v, OP_Integer, 0, pMWin->regEndRowid);
    sqlite3VdbeAddOp2(v, OP_OpenDup, pMWin->csrApp, pMWin->iEphCsr);
    return;
  }

  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
    FuncDef *p = pWin->pWFunc;
    if( (p->funcFlags & SQLITE_FUNC_MINMAX) && pWin->eStart!=TK_UNBOUNDED ){
      /* The inline versions of min() and max() require a single ephemeral
      ** table and 3 registers. The registers are used as follows:
      **
      **   regApp+0: slot to copy min()/max() argument to for MakeRecord
      **   regApp+1: integer value used to ensure keys are unique
      **   regApp+2: output of MakeRecord
      */
      ExprList *pList;
      KeyInfo *pKeyInfo;
      assert( ExprUseXList(pWin->pOwner) );
      pList = pWin->pOwner->x.pList;
      pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pList, 0, 0);
      pWin->csrApp = pParse->nTab++;
      pWin->regApp = pParse->nMem+1;
      pParse->nMem += 3;
      if( pKeyInfo && pWin->pWFunc->zName[1]=='i' ){
        assert( pKeyInfo->aSortFlags[0]==0 );
        pKeyInfo->aSortFlags[0] = KEYINFO_ORDER_DESC;

sqlite3.c  view on Meta::CPAN

/*
** Return the number of arguments passed to the window-function associated
** with the object passed as the only argument to this function.
*/
static int windowArgCount(Window *pWin){
  const ExprList *pList;
  assert( ExprUseXList(pWin->pOwner) );
  pList = pWin->pOwner->x.pList;
  return (pList ? pList->nExpr : 0);
}

typedef struct WindowCodeArg WindowCodeArg;
typedef struct WindowCsrAndReg WindowCsrAndReg;

/*
** See comments above struct WindowCodeArg.
*/
struct WindowCsrAndReg {
  int csr;                        /* Cursor number */
  int reg;                        /* First in array of peer values */
};

/*
** A single instance of this structure is allocated on the stack by
** sqlite3WindowCodeStep() and a pointer to it passed to the various helper
** routines. This is to reduce the number of arguments required by each
** helper function.
**
** regArg:
**   Each window function requires an accumulator register (just as an
**   ordinary aggregate function does). This variable is set to the first
**   in an array of accumulator registers - one for each window function
**   in the WindowCodeArg.pMWin list.
**
** eDelete:
**   The window functions implementation sometimes caches the input rows
**   that it processes in a temporary table. If it is not zero, this
**   variable indicates when rows may be removed from the temp table (in
**   order to reduce memory requirements - it would always be safe just
**   to leave them there). Possible values for eDelete are:
**
**      WINDOW_RETURN_ROW:
**        An input row can be discarded after it is returned to the caller.
**
**      WINDOW_AGGINVERSE:
**        An input row can be discarded after the window functions xInverse()
**        callbacks have been invoked in it.
**
**      WINDOW_AGGSTEP:
**        An input row can be discarded after the window functions xStep()
**        callbacks have been invoked in it.
**
** start,current,end
**   Consider a window-frame similar to the following:
**
**     (ORDER BY a, b GROUPS BETWEEN 2 PRECEDING AND 2 FOLLOWING)
**
**   The windows functions implementation caches the input rows in a temp
**   table, sorted by "a, b" (it actually populates the cache lazily, and
**   aggressively removes rows once they are no longer required, but that's
**   a mere detail). It keeps three cursors open on the temp table. One
**   (current) that points to the next row to return to the query engine
**   once its window function values have been calculated. Another (end)
**   points to the next row to call the xStep() method of each window function
**   on (so that it is 2 groups ahead of current). And a third (start) that
**   points to the next row to call the xInverse() method of each window
**   function on.
**
**   Each cursor (start, current and end) consists of a VDBE cursor
**   (WindowCsrAndReg.csr) and an array of registers (starting at
**   WindowCodeArg.reg) that always contains a copy of the peer values
**   read from the corresponding cursor.
**
**   Depending on the window-frame in question, all three cursors may not
**   be required. In this case both WindowCodeArg.csr and reg are set to
**   0.
*/
struct WindowCodeArg {
  Parse *pParse;             /* Parse context */
  Window *pMWin;             /* First in list of functions being processed */
  Vdbe *pVdbe;               /* VDBE object */
  int addrGosub;             /* OP_Gosub to this address to return one row */
  int regGosub;              /* Register used with OP_Gosub(addrGosub) */
  int regArg;                /* First in array of accumulator registers */
  int eDelete;               /* See above */
  int regRowid;

  WindowCsrAndReg start;
  WindowCsrAndReg current;
  WindowCsrAndReg end;
};

/*
** Generate VM code to read the window frames peer values from cursor csr into
** an array of registers starting at reg.
*/
static void windowReadPeerValues(
  WindowCodeArg *p,
  int csr,
  int reg
){
  Window *pMWin = p->pMWin;
  ExprList *pOrderBy = pMWin->pOrderBy;
  if( pOrderBy ){
    Vdbe *v = sqlite3GetVdbe(p->pParse);
    ExprList *pPart = pMWin->pPartition;
    int iColOff = pMWin->nBufferCol + (pPart ? pPart->nExpr : 0);
    int i;
    for(i=0; i<pOrderBy->nExpr; i++){
      sqlite3VdbeAddOp3(v, OP_Column, csr, iColOff+i, reg+i);
    }
  }
}

/*
** Generate VM code to invoke either xStep() (if bInverse is 0) or
** xInverse (if bInverse is non-zero) for each window function in the
** linked list starting at pMWin. Or, for built-in window functions
** that do not use the standard function API, generate the required
** inline VM code.
**
** If argument csr is greater than or equal to 0, then argument reg is
** the first register in an array of registers guaranteed to be large
** enough to hold the array of arguments for each function. In this case
** the arguments are extracted from the current row of csr into the
** array of registers before invoking OP_AggStep or OP_AggInverse
**
** Or, if csr is less than zero, then the array of registers at reg is
** already populated with all columns from the current row of the sub-query.
**
** If argument regPartSize is non-zero, then it is a register containing the
** number of rows in the current partition.
*/
static void windowAggStep(
  WindowCodeArg *p,
  Window *pMWin,                  /* Linked list of window functions */
  int csr,                        /* Read arguments from this cursor */
  int bInverse,                   /* True to invoke xInverse instead of xStep */
  int reg                         /* Array of registers */
){
  Parse *pParse = p->pParse;
  Vdbe *v = sqlite3GetVdbe(pParse);
  Window *pWin;
  for(pWin=pMWin; pWin; pWin=pWin->pNextWin){
    FuncDef *pFunc = pWin->pWFunc;
    int regArg;
    int nArg = pWin->bExprArgs ? 0 : windowArgCount(pWin);
    int i;
    int addrIf = 0;

    assert( bInverse==0 || pWin->eStart!=TK_UNBOUNDED );

    /* All OVER clauses in the same window function aggregate step must
    ** be the same. */
    assert( pWin==pMWin || sqlite3WindowCompare(pParse,pWin,pMWin,0)!=1 );

    for(i=0; i<nArg; i++){
      if( i!=1 || pFunc->zName!=nth_valueName ){
        sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+i, reg+i);
      }else{
        sqlite3VdbeAddOp3(v, OP_Column, pMWin->iEphCsr, pWin->iArgCol+i, reg+i);
      }
    }
    regArg = reg;

    if( pWin->pFilter ){
      int regTmp;
      assert( ExprUseXList(pWin->pOwner) );
      assert( pWin->bExprArgs || !nArg ||nArg==pWin->pOwner->x.pList->nExpr );
      assert( pWin->bExprArgs || nArg  ||pWin->pOwner->x.pList==0 );
      regTmp = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp3(v, OP_Column, csr, pWin->iArgCol+nArg,regTmp);
      addrIf = sqlite3VdbeAddOp3(v, OP_IfNot, regTmp, 0, 1);
      VdbeCoverage(v);
      sqlite3ReleaseTempReg(pParse, regTmp);
    }

    if( pMWin->regStartRowid==0
     && (pFunc->funcFlags & SQLITE_FUNC_MINMAX)
     && (pWin->eStart!=TK_UNBOUNDED)
    ){
      int addrIsNull = sqlite3VdbeAddOp1(v, OP_IsNull, regArg);
      VdbeCoverage(v);
      if( bInverse==0 ){
        sqlite3VdbeAddOp2(v, OP_AddImm, pWin->regApp+1, 1);
        sqlite3VdbeAddOp2(v, OP_SCopy, regArg, pWin->regApp);
        sqlite3VdbeAddOp3(v, OP_MakeRecord, pWin->regApp, 2, pWin->regApp+2);
        sqlite3VdbeAddOp2(v, OP_IdxInsert, pWin->csrApp, pWin->regApp+2);
      }else{
        sqlite3VdbeAddOp4Int(v, OP_SeekGE, pWin->csrApp, 0, regArg, 1);
        VdbeCoverageNeverTaken(v);
        sqlite3VdbeAddOp1(v, OP_Delete, pWin->csrApp);
        sqlite3VdbeJumpHere(v, sqlite3VdbeCurrentAddr(v)-2);
      }
      sqlite3VdbeJumpHere(v, addrIsNull);
    }else if( pWin->regApp ){
      assert( pWin->pFilter==0 );

sqlite3.c  view on Meta::CPAN


/*
** regOld and regNew are each the first register in an array of size
** pOrderBy->nExpr. This function generates code to compare the two
** arrays of registers using the collation sequences and other comparison
** parameters specified by pOrderBy.
**
** If the two arrays are not equal, the contents of regNew is copied to
** regOld and control falls through. Otherwise, if the contents of the arrays
** are equal, an OP_Goto is executed. The address of the OP_Goto is returned.
*/
static void windowIfNewPeer(
  Parse *pParse,
  ExprList *pOrderBy,
  int regNew,                     /* First in array of new values */
  int regOld,                     /* First in array of old values */
  int addr                        /* Jump here */
){
  Vdbe *v = sqlite3GetVdbe(pParse);
  if( pOrderBy ){
    int nVal = pOrderBy->nExpr;
    KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pOrderBy, 0, 0);
    sqlite3VdbeAddOp3(v, OP_Compare, regOld, regNew, nVal);
    sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
    sqlite3VdbeAddOp3(v, OP_Jump,
      sqlite3VdbeCurrentAddr(v)+1, addr, sqlite3VdbeCurrentAddr(v)+1
    );
    VdbeCoverageEqNe(v);
    sqlite3VdbeAddOp3(v, OP_Copy, regNew, regOld, nVal-1);
  }else{
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
  }
}

/*
** This function is called as part of generating VM programs for RANGE
** offset PRECEDING/FOLLOWING frame boundaries. Assuming "ASC" order for
** the ORDER BY term in the window, and that argument op is OP_Ge, it generates
** code equivalent to:
**
**   if( csr1.peerVal + regVal >= csr2.peerVal ) goto lbl;
**
** The value of parameter op may also be OP_Gt or OP_Le. In these cases the
** operator in the above pseudo-code is replaced with ">" or "<=", respectively.
**
** If the sort-order for the ORDER BY term in the window is DESC, then the
** comparison is reversed. Instead of adding regVal to csr1.peerVal, it is
** subtracted. And the comparison operator is inverted to - ">=" becomes "<=",
** ">" becomes "<", and so on. So, with DESC sort order, if the argument op
** is OP_Ge, the generated code is equivalent to:
**
**   if( csr1.peerVal - regVal <= csr2.peerVal ) goto lbl;
**
** A special type of arithmetic is used such that if csr1.peerVal is not
** a numeric type (real or integer), then the result of the addition
** or subtraction is a a copy of csr1.peerVal.
*/
static void windowCodeRangeTest(
  WindowCodeArg *p,
  int op,                         /* OP_Ge, OP_Gt, or OP_Le */
  int csr1,                       /* Cursor number for cursor 1 */
  int regVal,                     /* Register containing non-negative number */
  int csr2,                       /* Cursor number for cursor 2 */
  int lbl                         /* Jump destination if condition is true */
){
  Parse *pParse = p->pParse;
  Vdbe *v = sqlite3GetVdbe(pParse);
  ExprList *pOrderBy = p->pMWin->pOrderBy;  /* ORDER BY clause for window */
  int reg1 = sqlite3GetTempReg(pParse);     /* Reg. for csr1.peerVal+regVal */
  int reg2 = sqlite3GetTempReg(pParse);     /* Reg. for csr2.peerVal */
  int regString = ++pParse->nMem;           /* Reg. for constant value '' */
  int arith = OP_Add;                       /* OP_Add or OP_Subtract */
  int addrGe;                               /* Jump destination */
  int addrDone = sqlite3VdbeMakeLabel(pParse);   /* Address past OP_Ge */
  CollSeq *pColl;

  /* Read the peer-value from each cursor into a register */
  windowReadPeerValues(p, csr1, reg1);
  windowReadPeerValues(p, csr2, reg2);

  assert( op==OP_Ge || op==OP_Gt || op==OP_Le );
  assert( pOrderBy && pOrderBy->nExpr==1 );
  if( pOrderBy->a[0].fg.sortFlags & KEYINFO_ORDER_DESC ){
    switch( op ){
      case OP_Ge: op = OP_Le; break;
      case OP_Gt: op = OP_Lt; break;
      default: assert( op==OP_Le ); op = OP_Ge; break;
    }
    arith = OP_Subtract;
  }

  VdbeModuleComment((v, "CodeRangeTest: if( R%d %s R%d %s R%d ) goto lbl",
      reg1, (arith==OP_Add ? "+" : "-"), regVal,
      ((op==OP_Ge) ? ">=" : (op==OP_Le) ? "<=" : (op==OP_Gt) ? ">" : "<"), reg2
  ));

  /* If the BIGNULL flag is set for the ORDER BY, then it is required to
  ** consider NULL values to be larger than all other values, instead of
  ** the usual smaller. The VDBE opcodes OP_Ge and so on do not handle this
  ** (and adding that capability causes a performance regression), so
  ** instead if the BIGNULL flag is set then cases where either reg1 or
  ** reg2 are NULL are handled separately in the following block. The code
  ** generated is equivalent to:
  **
  **   if( reg1 IS NULL ){
  **     if( op==OP_Ge ) goto lbl;
  **     if( op==OP_Gt && reg2 IS NOT NULL ) goto lbl;
  **     if( op==OP_Le && reg2 IS NULL ) goto lbl;
  **   }else if( reg2 IS NULL ){
  **     if( op==OP_Le ) goto lbl;
  **   }
  **
  ** Additionally, if either reg1 or reg2 are NULL but the jump to lbl is
  ** not taken, control jumps over the comparison operator coded below this
  ** block.  */
  if( pOrderBy->a[0].fg.sortFlags & KEYINFO_ORDER_BIGNULL ){
    /* This block runs if reg1 contains a NULL. */
    int addr = sqlite3VdbeAddOp1(v, OP_NotNull, reg1); VdbeCoverage(v);
    switch( op ){
      case OP_Ge:
        sqlite3VdbeAddOp2(v, OP_Goto, 0, lbl);
        break;
      case OP_Gt:
        sqlite3VdbeAddOp2(v, OP_NotNull, reg2, lbl);
        VdbeCoverage(v);
        break;
      case OP_Le:
        sqlite3VdbeAddOp2(v, OP_IsNull, reg2, lbl);
        VdbeCoverage(v);
        break;
      default: assert( op==OP_Lt ); /* no-op */ break;
    }
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrDone);

    /* This block runs if reg1 is not NULL, but reg2 is. */
    sqlite3VdbeJumpHere(v, addr);
    sqlite3VdbeAddOp2(v, OP_IsNull, reg2,
                      (op==OP_Gt || op==OP_Ge) ? addrDone : lbl);
    VdbeCoverage(v);
  }

  /* Register reg1 currently contains csr1.peerVal (the peer-value from csr1).
  ** This block adds (or subtracts for DESC) the numeric value in regVal
  ** from it. Or, if reg1 is not numeric (it is a NULL, a text value or a blob),
  ** then leave reg1 as it is. In pseudo-code, this is implemented as:
  **
  **   if( reg1>='' ) goto addrGe;
  **   reg1 = reg1 +/- regVal
  **   addrGe:
  **
  ** Since all strings and blobs are greater-than-or-equal-to an empty string,
  ** the add/subtract is skipped for these, as required. If reg1 is a NULL,
  ** then the arithmetic is performed, but since adding or subtracting from
  ** NULL is always NULL anyway, this case is handled as required too.  */
  sqlite3VdbeAddOp4(v, OP_String8, 0, regString, 0, "", P4_STATIC);
  addrGe = sqlite3VdbeAddOp3(v, OP_Ge, regString, 0, reg1);
  VdbeCoverage(v);
  if( (op==OP_Ge && arith==OP_Add) || (op==OP_Le && arith==OP_Subtract) ){
    sqlite3VdbeAddOp3(v, op, reg2, lbl, reg1); VdbeCoverage(v);
  }
  sqlite3VdbeAddOp3(v, arith, regVal, reg1, reg1);
  sqlite3VdbeJumpHere(v, addrGe);

  /* Compare registers reg2 and reg1, taking the jump if required. Note that
  ** control skips over this test if the BIGNULL flag is set and either
  ** reg1 or reg2 contain a NULL value.  */
  sqlite3VdbeAddOp3(v, op, reg2, lbl, reg1); VdbeCoverage(v);
  pColl = sqlite3ExprNNCollSeq(pParse, pOrderBy->a[0].pExpr);
  sqlite3VdbeAppendP4(v, (void*)pColl, P4_COLLSEQ);
  sqlite3VdbeChangeP5(v, SQLITE_NULLEQ);
  sqlite3VdbeResolveLabel(v, addrDone);

  assert( op==OP_Ge || op==OP_Gt || op==OP_Lt || op==OP_Le );
  testcase(op==OP_Ge); VdbeCoverageIf(v, op==OP_Ge);
  testcase(op==OP_Lt); VdbeCoverageIf(v, op==OP_Lt);
  testcase(op==OP_Le); VdbeCoverageIf(v, op==OP_Le);
  testcase(op==OP_Gt); VdbeCoverageIf(v, op==OP_Gt);
  sqlite3ReleaseTempReg(pParse, reg1);
  sqlite3ReleaseTempReg(pParse, reg2);

  VdbeModuleComment((v, "CodeRangeTest: end"));
}

/*
** Helper function for sqlite3WindowCodeStep(). Each call to this function
** generates VM code for a single RETURN_ROW, AGGSTEP or AGGINVERSE
** operation. Refer to the header comment for sqlite3WindowCodeStep() for
** details.
*/
static int windowCodeOp(
 WindowCodeArg *p,                /* Context object */
 int op,                          /* WINDOW_RETURN_ROW, AGGSTEP or AGGINVERSE */
 int regCountdown,                /* Register for OP_IfPos countdown */
 int jumpOnEof                    /* Jump here if stepped cursor reaches EOF */
){
  int csr, reg;
  Parse *pParse = p->pParse;
  Window *pMWin = p->pMWin;
  int ret = 0;
  Vdbe *v = p->pVdbe;
  int addrContinue = 0;
  int bPeer = (pMWin->eFrmType!=TK_ROWS);

  int lblDone = sqlite3VdbeMakeLabel(pParse);
  int addrNextRange = 0;

  /* Special case - WINDOW_AGGINVERSE is always a no-op if the frame
  ** starts with UNBOUNDED PRECEDING. */
  if( op==WINDOW_AGGINVERSE && pMWin->eStart==TK_UNBOUNDED ){
    assert( regCountdown==0 && jumpOnEof==0 );
    return 0;
  }

  if( regCountdown>0 ){
    if( pMWin->eFrmType==TK_RANGE ){
      addrNextRange = sqlite3VdbeCurrentAddr(v);
      assert( op==WINDOW_AGGINVERSE || op==WINDOW_AGGSTEP );
      if( op==WINDOW_AGGINVERSE ){
        if( pMWin->eStart==TK_FOLLOWING ){
          windowCodeRangeTest(
              p, OP_Le, p->current.csr, regCountdown, p->start.csr, lblDone
          );
        }else{
          windowCodeRangeTest(
              p, OP_Ge, p->start.csr, regCountdown, p->current.csr, lblDone
          );
        }
      }else{
        windowCodeRangeTest(
            p, OP_Gt, p->end.csr, regCountdown, p->current.csr, lblDone
        );
      }
    }else{
      sqlite3VdbeAddOp3(v, OP_IfPos, regCountdown, lblDone, 1);
      VdbeCoverage(v);
    }
  }

  if( op==WINDOW_RETURN_ROW && pMWin->regStartRowid==0 ){
    windowAggFinal(p, 0);
  }
  addrContinue = sqlite3VdbeCurrentAddr(v);

  /* If this is a (RANGE BETWEEN a FOLLOWING AND b FOLLOWING) or
  ** (RANGE BETWEEN b PRECEDING AND a PRECEDING) frame, ensure the
  ** start cursor does not advance past the end cursor within the
  ** temporary table. It otherwise might, if (a>b). Also ensure that,
  ** if the input cursor is still finding new rows, that the end
  ** cursor does not go past it to EOF. */
  if( pMWin->eStart==pMWin->eEnd && regCountdown
   && pMWin->eFrmType==TK_RANGE
  ){
    int regRowid1 = sqlite3GetTempReg(pParse);
    int regRowid2 = sqlite3GetTempReg(pParse);
    if( op==WINDOW_AGGINVERSE ){
      sqlite3VdbeAddOp2(v, OP_Rowid, p->start.csr, regRowid1);
      sqlite3VdbeAddOp2(v, OP_Rowid, p->end.csr, regRowid2);
      sqlite3VdbeAddOp3(v, OP_Ge, regRowid2, lblDone, regRowid1);
      VdbeCoverage(v);
    }else if( p->regRowid ){
      sqlite3VdbeAddOp2(v, OP_Rowid, p->end.csr, regRowid1);
      sqlite3VdbeAddOp3(v, OP_Ge, p->regRowid, lblDone, regRowid1);
      VdbeCoverageNeverNull(v);
    }
    sqlite3ReleaseTempReg(pParse, regRowid1);
    sqlite3ReleaseTempReg(pParse, regRowid2);
    assert( pMWin->eStart==TK_PRECEDING || pMWin->eStart==TK_FOLLOWING );
  }

  switch( op ){
    case WINDOW_RETURN_ROW:
      csr = p->current.csr;
      reg = p->current.reg;
      windowReturnOneRow(p);
      break;

    case WINDOW_AGGINVERSE:
      csr = p->start.csr;
      reg = p->start.reg;
      if( pMWin->regStartRowid ){
        assert( pMWin->regEndRowid );
        sqlite3VdbeAddOp2(v, OP_AddImm, pMWin->regStartRowid, 1);
      }else{
        windowAggStep(p, pMWin, csr, 1, p->regArg);
      }
      break;

    default:
      assert( op==WINDOW_AGGSTEP );
      csr = p->end.csr;
      reg = p->end.reg;
      if( pMWin->regStartRowid ){
        assert( pMWin->regEndRowid );
        sqlite3VdbeAddOp2(v, OP_AddImm, pMWin->regEndRowid, 1);
      }else{
        windowAggStep(p, pMWin, csr, 0, p->regArg);
      }
      break;
  }

  if( op==p->eDelete ){
    sqlite3VdbeAddOp1(v, OP_Delete, csr);
    sqlite3VdbeChangeP5(v, OPFLAG_SAVEPOSITION);
  }

  if( jumpOnEof ){
    sqlite3VdbeAddOp2(v, OP_Next, csr, sqlite3VdbeCurrentAddr(v)+2);
    VdbeCoverage(v);
    ret = sqlite3VdbeAddOp0(v, OP_Goto);

sqlite3.c  view on Meta::CPAN

/*
** Return a copy of the linked list of Window objects passed as the
** second argument.
*/
SQLITE_PRIVATE Window *sqlite3WindowListDup(sqlite3 *db, Window *p){
  Window *pWin;
  Window *pRet = 0;
  Window **pp = &pRet;

  for(pWin=p; pWin; pWin=pWin->pNextWin){
    *pp = sqlite3WindowDup(db, 0, pWin);
    if( *pp==0 ) break;
    pp = &((*pp)->pNextWin);
  }

  return pRet;
}

/*
** Return true if it can be determined at compile time that expression
** pExpr evaluates to a value that, when cast to an integer, is greater
** than zero. False otherwise.
**
** If an OOM error occurs, this function sets the Parse.db.mallocFailed
** flag and returns zero.
*/
static int windowExprGtZero(Parse *pParse, Expr *pExpr){
  int ret = 0;
  sqlite3 *db = pParse->db;
  sqlite3_value *pVal = 0;
  sqlite3ValueFromExpr(db, pExpr, db->enc, SQLITE_AFF_NUMERIC, &pVal);
  if( pVal && sqlite3_value_int(pVal)>0 ){
    ret = 1;
  }
  sqlite3ValueFree(pVal);
  return ret;
}

/*
** sqlite3WhereBegin() has already been called for the SELECT statement
** passed as the second argument when this function is invoked. It generates
** code to populate the Window.regResult register for each window function
** and invoke the sub-routine at instruction addrGosub once for each row.
** sqlite3WhereEnd() is always called before returning.
**
** This function handles several different types of window frames, which
** require slightly different processing. The following pseudo code is
** used to implement window frames of the form:
**
**   ROWS BETWEEN <expr1> PRECEDING AND <expr2> FOLLOWING
**
** Other window frame types use variants of the following:
**
**     ... loop started by sqlite3WhereBegin() ...
**       if( new partition ){
**         Gosub flush
**       }
**       Insert new row into eph table.
**
**       if( first row of partition ){
**         // Rewind three cursors, all open on the eph table.
**         Rewind(csrEnd);
**         Rewind(csrStart);
**         Rewind(csrCurrent);
**
**         regEnd = <expr2>          // FOLLOWING expression
**         regStart = <expr1>        // PRECEDING expression
**       }else{
**         // First time this branch is taken, the eph table contains two
**         // rows. The first row in the partition, which all three cursors
**         // currently point to, and the following row.
**         AGGSTEP
**         if( (regEnd--)<=0 ){
**           RETURN_ROW
**           if( (regStart--)<=0 ){
**             AGGINVERSE
**           }
**         }
**       }
**     }
**     flush:
**       AGGSTEP
**       while( 1 ){
**         RETURN ROW
**         if( csrCurrent is EOF ) break;
**         if( (regStart--)<=0 ){
**           AggInverse(csrStart)
**           Next(csrStart)
**         }
**       }
**
** The pseudo-code above uses the following shorthand:
**
**   AGGSTEP:    invoke the aggregate xStep() function for each window function
**               with arguments read from the current row of cursor csrEnd, then
**               step cursor csrEnd forward one row (i.e. sqlite3BtreeNext()).
**
**   RETURN_ROW: return a row to the caller based on the contents of the
**               current row of csrCurrent and the current state of all
**               aggregates. Then step cursor csrCurrent forward one row.
**
**   AGGINVERSE: invoke the aggregate xInverse() function for each window
**               functions with arguments read from the current row of cursor
**               csrStart. Then step csrStart forward one row.
**
** There are two other ROWS window frames that are handled significantly
** differently from the above - "BETWEEN <expr> PRECEDING AND <expr> PRECEDING"
** and "BETWEEN <expr> FOLLOWING AND <expr> FOLLOWING". These are special
** cases because they change the order in which the three cursors (csrStart,
** csrCurrent and csrEnd) iterate through the ephemeral table. Cases that
** use UNBOUNDED or CURRENT ROW are much simpler variations on one of these
** three.
**
**   ROWS BETWEEN <expr1> PRECEDING AND <expr2> PRECEDING
**
**     ... loop started by sqlite3WhereBegin() ...
**       if( new partition ){
**         Gosub flush
**       }
**       Insert new row into eph table.
**       if( first row of partition ){
**         Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
**         regEnd = <expr2>
**         regStart = <expr1>
**       }else{
**         if( (regEnd--)<=0 ){
**           AGGSTEP
**         }
**         RETURN_ROW
**         if( (regStart--)<=0 ){
**           AGGINVERSE
**         }
**       }
**     }
**     flush:
**       if( (regEnd--)<=0 ){
**         AGGSTEP
**       }
**       RETURN_ROW
**
**
**   ROWS BETWEEN <expr1> FOLLOWING AND <expr2> FOLLOWING
**
**   ... loop started by sqlite3WhereBegin() ...
**     if( new partition ){
**       Gosub flush
**     }
**     Insert new row into eph table.
**     if( first row of partition ){
**       Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
**       regEnd = <expr2>
**       regStart = regEnd - <expr1>
**     }else{
**       AGGSTEP
**       if( (regEnd--)<=0 ){
**         RETURN_ROW
**       }
**       if( (regStart--)<=0 ){
**         AGGINVERSE
**       }
**     }
**   }
**   flush:
**     AGGSTEP
**     while( 1 ){
**       if( (regEnd--)<=0 ){
**         RETURN_ROW
**         if( eof ) break;
**       }

sqlite3.c  view on Meta::CPAN

**       if( (regStart--)<=0 ){
**         AGGINVERSE
**         if( eof ) break
**       }
**       RETURN_ROW
**     }
**     while( !eof csrCurrent ){
**       RETURN_ROW
**     }
**
** Also requiring special handling are the cases:
**
**   ROWS BETWEEN <expr1> PRECEDING AND <expr2> PRECEDING
**   ROWS BETWEEN <expr1> FOLLOWING AND <expr2> FOLLOWING
**
** when (expr1 < expr2). This is detected at runtime, not by this function.
** To handle this case, the pseudo-code programs depicted above are modified
** slightly to be:
**
**     ... loop started by sqlite3WhereBegin() ...
**     if( new partition ){
**       Gosub flush
**     }
**     Insert new row into eph table.
**     if( first row of partition ){
**       Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
**       regEnd = <expr2>
**       regStart = <expr1>
**       if( regEnd < regStart ){
**         RETURN_ROW
**         delete eph table contents
**         continue
**       }
**     ...
**
** The new "continue" statement in the above jumps to the next iteration
** of the outer loop - the one started by sqlite3WhereBegin().
**
** The various GROUPS cases are implemented using the same patterns as
** ROWS. The VM code is modified slightly so that:
**
**   1. The else branch in the main loop is only taken if the row just
**      added to the ephemeral table is the start of a new group. In
**      other words, it becomes:
**
**         ... loop started by sqlite3WhereBegin() ...
**         if( new partition ){
**           Gosub flush
**         }
**         Insert new row into eph table.
**         if( first row of partition ){
**           Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
**           regEnd = <expr2>
**           regStart = <expr1>
**         }else if( new group ){
**           ...
**         }
**       }
**
**   2. Instead of processing a single row, each RETURN_ROW, AGGSTEP or
**      AGGINVERSE step processes the current row of the relevant cursor and
**      all subsequent rows belonging to the same group.
**
** RANGE window frames are a little different again. As for GROUPS, the
** main loop runs once per group only. And RETURN_ROW, AGGSTEP and AGGINVERSE
** deal in groups instead of rows. As for ROWS and GROUPS, there are three
** basic cases:
**
**   RANGE BETWEEN <expr1> PRECEDING AND <expr2> FOLLOWING
**
**     ... loop started by sqlite3WhereBegin() ...
**       if( new partition ){
**         Gosub flush
**       }
**       Insert new row into eph table.
**       if( first row of partition ){
**         Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
**         regEnd = <expr2>
**         regStart = <expr1>
**       }else{
**         AGGSTEP
**         while( (csrCurrent.key + regEnd) < csrEnd.key ){
**           RETURN_ROW
**           while( csrStart.key + regStart) < csrCurrent.key ){
**             AGGINVERSE
**           }
**         }
**       }
**     }
**     flush:
**       AGGSTEP
**       while( 1 ){
**         RETURN ROW
**         if( csrCurrent is EOF ) break;
**           while( csrStart.key + regStart) < csrCurrent.key ){
**             AGGINVERSE
**           }
**         }
**       }
**
** In the above notation, "csr.key" means the current value of the ORDER BY
** expression (there is only ever 1 for a RANGE that uses an <expr> FOLLOWING
** or <expr PRECEDING) read from cursor csr.
**
**   RANGE BETWEEN <expr1> PRECEDING AND <expr2> PRECEDING
**
**     ... loop started by sqlite3WhereBegin() ...
**       if( new partition ){
**         Gosub flush
**       }
**       Insert new row into eph table.
**       if( first row of partition ){
**         Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
**         regEnd = <expr2>
**         regStart = <expr1>
**       }else{
**         while( (csrEnd.key + regEnd) <= csrCurrent.key ){
**           AGGSTEP
**         }
**         while( (csrStart.key + regStart) < csrCurrent.key ){
**           AGGINVERSE
**         }
**         RETURN_ROW
**       }
**     }
**     flush:
**       while( (csrEnd.key + regEnd) <= csrCurrent.key ){
**         AGGSTEP
**       }
**       while( (csrStart.key + regStart) < csrCurrent.key ){
**         AGGINVERSE
**       }
**       RETURN_ROW
**
**   RANGE BETWEEN <expr1> FOLLOWING AND <expr2> FOLLOWING
**
**     ... loop started by sqlite3WhereBegin() ...
**       if( new partition ){
**         Gosub flush
**       }
**       Insert new row into eph table.
**       if( first row of partition ){
**         Rewind(csrEnd) ; Rewind(csrStart) ; Rewind(csrCurrent)
**         regEnd = <expr2>
**         regStart = <expr1>
**       }else{
**         AGGSTEP
**         while( (csrCurrent.key + regEnd) < csrEnd.key ){
**           while( (csrCurrent.key + regStart) > csrStart.key ){
**             AGGINVERSE
**           }
**           RETURN_ROW
**         }
**       }
**     }
**     flush:
**       AGGSTEP
**       while( 1 ){
**         while( (csrCurrent.key + regStart) > csrStart.key ){
**           AGGINVERSE
**           if( eof ) break "while( 1 )" loop.
**         }
**         RETURN_ROW

sqlite3.c  view on Meta::CPAN

  s.pVdbe = v;
  s.regGosub = regGosub;
  s.addrGosub = addrGosub;
  s.current.csr = pMWin->iEphCsr;
  csrWrite = s.current.csr+1;
  s.start.csr = s.current.csr+2;
  s.end.csr = s.current.csr+3;

  /* Figure out when rows may be deleted from the ephemeral table. There
  ** are four options - they may never be deleted (eDelete==0), they may
  ** be deleted as soon as they are no longer part of the window frame
  ** (eDelete==WINDOW_AGGINVERSE), they may be deleted as after the row
  ** has been returned to the caller (WINDOW_RETURN_ROW), or they may
  ** be deleted after they enter the frame (WINDOW_AGGSTEP). */
  switch( pMWin->eStart ){
    case TK_FOLLOWING:
      if( pMWin->eFrmType!=TK_RANGE
       && windowExprGtZero(pParse, pMWin->pStart)
      ){
        s.eDelete = WINDOW_RETURN_ROW;
      }
      break;
    case TK_UNBOUNDED:
      if( windowCacheFrame(pMWin)==0 ){
        if( pMWin->eEnd==TK_PRECEDING ){
          if( pMWin->eFrmType!=TK_RANGE
           && windowExprGtZero(pParse, pMWin->pEnd)
          ){
            s.eDelete = WINDOW_AGGSTEP;
          }
        }else{
          s.eDelete = WINDOW_RETURN_ROW;
        }
      }
      break;
    default:
      s.eDelete = WINDOW_AGGINVERSE;
      break;
  }

  /* Allocate registers for the array of values from the sub-query, the
  ** same values in record form, and the rowid used to insert said record
  ** into the ephemeral table.  */
  regNew = pParse->nMem+1;
  pParse->nMem += nInput;
  regRecord = ++pParse->nMem;
  s.regRowid = ++pParse->nMem;

  /* If the window frame contains an "<expr> PRECEDING" or "<expr> FOLLOWING"
  ** clause, allocate registers to store the results of evaluating each
  ** <expr>.  */
  if( pMWin->eStart==TK_PRECEDING || pMWin->eStart==TK_FOLLOWING ){
    regStart = ++pParse->nMem;
  }
  if( pMWin->eEnd==TK_PRECEDING || pMWin->eEnd==TK_FOLLOWING ){
    regEnd = ++pParse->nMem;
  }

  /* If this is not a "ROWS BETWEEN ..." frame, then allocate arrays of
  ** registers to store copies of the ORDER BY expressions (peer values)
  ** for the main loop, and for each cursor (start, current and end). */
  if( pMWin->eFrmType!=TK_ROWS ){
    int nPeer = (pOrderBy ? pOrderBy->nExpr : 0);
    regNewPeer = regNew + pMWin->nBufferCol;
    if( pMWin->pPartition ) regNewPeer += pMWin->pPartition->nExpr;
    regPeer = pParse->nMem+1;       pParse->nMem += nPeer;
    s.start.reg = pParse->nMem+1;   pParse->nMem += nPeer;
    s.current.reg = pParse->nMem+1; pParse->nMem += nPeer;
    s.end.reg = pParse->nMem+1;     pParse->nMem += nPeer;
  }

  /* Load the column values for the row returned by the sub-select
  ** into an array of registers starting at regNew. Assemble them into
  ** a record in register regRecord. */
  for(iInput=0; iInput<nInput; iInput++){
    sqlite3VdbeAddOp3(v, OP_Column, csrInput, iInput, regNew+iInput);
  }
  sqlite3VdbeAddOp3(v, OP_MakeRecord, regNew, nInput, regRecord);

  /* An input row has just been read into an array of registers starting
  ** at regNew. If the window has a PARTITION clause, this block generates
  ** VM code to check if the input row is the start of a new partition.
  ** If so, it does an OP_Gosub to an address to be filled in later. The
  ** address of the OP_Gosub is stored in local variable addrGosubFlush. */
  if( pMWin->pPartition ){
    int addr;
    ExprList *pPart = pMWin->pPartition;
    int nPart = pPart->nExpr;
    int regNewPart = regNew + pMWin->nBufferCol;
    KeyInfo *pKeyInfo = sqlite3KeyInfoFromExprList(pParse, pPart, 0, 0);

    regFlushPart = ++pParse->nMem;
    addr = sqlite3VdbeAddOp3(v, OP_Compare, regNewPart, pMWin->regPart, nPart);
    sqlite3VdbeAppendP4(v, (void*)pKeyInfo, P4_KEYINFO);
    sqlite3VdbeAddOp3(v, OP_Jump, addr+2, addr+4, addr+2);
    VdbeCoverageEqNe(v);
    addrGosubFlush = sqlite3VdbeAddOp1(v, OP_Gosub, regFlushPart);
    VdbeComment((v, "call flush_partition"));
    sqlite3VdbeAddOp3(v, OP_Copy, regNewPart, pMWin->regPart, nPart-1);
  }

  /* Insert the new row into the ephemeral table */
  sqlite3VdbeAddOp2(v, OP_NewRowid, csrWrite, s.regRowid);
  sqlite3VdbeAddOp3(v, OP_Insert, csrWrite, regRecord, s.regRowid);
  addrNe = sqlite3VdbeAddOp3(v, OP_Ne, pMWin->regOne, 0, s.regRowid);
  VdbeCoverageNeverNull(v);

  /* This block is run for the first row of each partition */
  s.regArg = windowInitAccum(pParse, pMWin);

  if( regStart ){
    sqlite3ExprCode(pParse, pMWin->pStart, regStart);
    windowCheckValue(pParse, regStart, 0 + (pMWin->eFrmType==TK_RANGE?3:0));
  }
  if( regEnd ){
    sqlite3ExprCode(pParse, pMWin->pEnd, regEnd);
    windowCheckValue(pParse, regEnd, 1 + (pMWin->eFrmType==TK_RANGE?3:0));
  }

  if( pMWin->eFrmType!=TK_RANGE && pMWin->eStart==pMWin->eEnd && regStart ){
    int op = ((pMWin->eStart==TK_FOLLOWING) ? OP_Ge : OP_Le);

sqlite3.c  view on Meta::CPAN


  for(i=sqliteHashFirst(&db->aFunc); i; i=sqliteHashNext(i)){
    FuncDef *pNext, *p;
    p = sqliteHashData(i);
    do{
      functionDestroy(db, p);
      pNext = p->pNext;
      sqlite3DbFree(db, p);
      p = pNext;
    }while( p );
  }
  sqlite3HashClear(&db->aFunc);
  for(i=sqliteHashFirst(&db->aCollSeq); i; i=sqliteHashNext(i)){
    CollSeq *pColl = (CollSeq *)sqliteHashData(i);
    /* Invoke any destructors registered for collation sequence user data. */
    for(j=0; j<3; j++){
      if( pColl[j].xDel ){
        pColl[j].xDel(pColl[j].pUser);
      }
    }
    sqlite3DbFree(db, pColl);
  }
  sqlite3HashClear(&db->aCollSeq);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  for(i=sqliteHashFirst(&db->aModule); i; i=sqliteHashNext(i)){
    Module *pMod = (Module *)sqliteHashData(i);
    sqlite3VtabEponymousTableClear(db, pMod);
    sqlite3VtabModuleUnref(db, pMod);
  }
  sqlite3HashClear(&db->aModule);
#endif

  sqlite3Error(db, SQLITE_OK); /* Deallocates any cached error strings. */
  sqlite3ValueFree(db->pErr);
  sqlite3CloseExtensions(db);

  db->eOpenState = SQLITE_STATE_ERROR;

  /* The temp-database schema is allocated differently from the other schema
  ** objects (using sqliteMalloc() directly, instead of sqlite3BtreeSchema()).
  ** So it needs to be freed here. Todo: Why not roll the temp schema into
  ** the same sqliteMalloc() as the one that allocates the database
  ** structure?
  */
  sqlite3DbFree(db, db->aDb[1].pSchema);
  if( db->xAutovacDestr ){
    db->xAutovacDestr(db->pAutovacPagesArg);
  }
  sqlite3_mutex_leave(db->mutex);
  db->eOpenState = SQLITE_STATE_CLOSED;
  sqlite3_mutex_free(db->mutex);
  assert( sqlite3LookasideUsed(db,0)==0 );
  if( db->lookaside.bMalloced ){
    sqlite3_free(db->lookaside.pStart);
  }
  sqlite3_free(db);
}

/*
** Rollback all database files.  If tripCode is not SQLITE_OK, then
** any write cursors are invalidated ("tripped" - as in "tripping a circuit
** breaker") and made to return tripCode if there are any further
** attempts to use that cursor.  Read cursors remain open and valid
** but are "saved" in case the table pages are moved around.
*/
SQLITE_PRIVATE void sqlite3RollbackAll(sqlite3 *db, int tripCode){
  int i;
  int inTrans = 0;
  int schemaChange;
  assert( sqlite3_mutex_held(db->mutex) );
  sqlite3BeginBenignMalloc();

  /* Obtain all b-tree mutexes before making any calls to BtreeRollback().
  ** This is important in case the transaction being rolled back has
  ** modified the database schema. If the b-tree mutexes are not taken
  ** here, then another shared-cache connection might sneak in between
  ** the database rollback and schema reset, which can cause false
  ** corruption reports in some cases.  */
  sqlite3BtreeEnterAll(db);
  schemaChange = (db->mDbFlags & DBFLAG_SchemaChange)!=0 && db->init.busy==0;

  for(i=0; i<db->nDb; i++){
    Btree *p = db->aDb[i].pBt;
    if( p ){
      if( sqlite3BtreeTxnState(p)==SQLITE_TXN_WRITE ){
        inTrans = 1;
      }
      sqlite3BtreeRollback(p, tripCode, !schemaChange);
    }
  }
  sqlite3VtabRollback(db);
  sqlite3EndBenignMalloc();

  if( schemaChange ){
    sqlite3ExpirePreparedStatements(db, 0);
    sqlite3ResetAllSchemasOfConnection(db);
  }
  sqlite3BtreeLeaveAll(db);

  /* Any deferred constraint violations have now been resolved. */
  db->nDeferredCons = 0;
  db->nDeferredImmCons = 0;
  db->flags &= ~(u64)(SQLITE_DeferFKs|SQLITE_CorruptRdOnly);

  /* If one has been configured, invoke the rollback-hook callback */
  if( db->xRollbackCallback && (inTrans || !db->autoCommit) ){
    db->xRollbackCallback(db->pRollbackArg);
  }
}

/*
** Return a static string containing the name corresponding to the error code
** specified in the argument.
*/
#if defined(SQLITE_NEED_ERR_NAME)
SQLITE_PRIVATE const char *sqlite3ErrName(int rc){
  const char *zName = 0;
  int i, origRc = rc;
  for(i=0; i<2 && zName==0; i++, rc &= 0xff){
    switch( rc ){
      case SQLITE_OK:                 zName = "SQLITE_OK";                break;
      case SQLITE_ERROR:              zName = "SQLITE_ERROR";             break;
      case SQLITE_ERROR_SNAPSHOT:     zName = "SQLITE_ERROR_SNAPSHOT";    break;

sqlite3.c  view on Meta::CPAN

*/
#ifndef _FTSINT_H
#define _FTSINT_H

/*
** Activate assert() only if SQLITE_TEST is enabled.
*/
#if !defined(NDEBUG) && !defined(SQLITE_DEBUG)
# define NDEBUG 1
#endif

/* #include <assert.h> */
/* #include <stdlib.h> */
/* #include <stddef.h> */
/* #include <stdio.h> */
/* #include <string.h> */
/* #include <stdarg.h> */

/* FTS3/FTS4 require virtual tables */
#ifdef SQLITE_OMIT_VIRTUALTABLE
# undef SQLITE_ENABLE_FTS3
# undef SQLITE_ENABLE_FTS4
#endif

/*
** FTS4 is really an extension for FTS3.  It is enabled using the
** SQLITE_ENABLE_FTS3 macro.  But to avoid confusion we also all
** the SQLITE_ENABLE_FTS4 macro to serve as an alisse for SQLITE_ENABLE_FTS3.
*/
#if defined(SQLITE_ENABLE_FTS4) && !defined(SQLITE_ENABLE_FTS3)
# define SQLITE_ENABLE_FTS3
#endif

#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)

/* If not building as part of the core, include sqlite3ext.h. */
#ifndef SQLITE_CORE
/* # include "sqlite3ext.h" */
SQLITE_EXTENSION_INIT3
#endif

/* #include "sqlite3.h" */
/************** Include fts3_tokenizer.h in the middle of fts3Int.h **********/
/************** Begin file fts3_tokenizer.h **********************************/
/*
** 2006 July 10
**
** The author disclaims copyright to this source code.
**
*************************************************************************
** Defines the interface to tokenizers used by fulltext-search.  There
** are three basic components:
**
** sqlite3_tokenizer_module is a singleton defining the tokenizer
** interface functions.  This is essentially the class structure for
** tokenizers.
**
** sqlite3_tokenizer is used to define a particular tokenizer, perhaps
** including customization information defined at creation time.
**
** sqlite3_tokenizer_cursor is generated by a tokenizer to generate
** tokens from a particular input.
*/
#ifndef _FTS3_TOKENIZER_H_
#define _FTS3_TOKENIZER_H_

/* TODO(shess) Only used for SQLITE_OK and SQLITE_DONE at this time.
** If tokenizers are to be allowed to call sqlite3_*() functions, then
** we will need a way to register the API consistently.
*/
/* #include "sqlite3.h" */

/*
** Structures used by the tokenizer interface. When a new tokenizer
** implementation is registered, the caller provides a pointer to
** an sqlite3_tokenizer_module containing pointers to the callback
** functions that make up an implementation.
**
** When an fts3 table is created, it passes any arguments passed to
** the tokenizer clause of the CREATE VIRTUAL TABLE statement to the
** sqlite3_tokenizer_module.xCreate() function of the requested tokenizer
** implementation. The xCreate() function in turn returns an
** sqlite3_tokenizer structure representing the specific tokenizer to
** be used for the fts3 table (customized by the tokenizer clause arguments).
**
** To tokenize an input buffer, the sqlite3_tokenizer_module.xOpen()
** method is called. It returns an sqlite3_tokenizer_cursor object
** that may be used to tokenize a specific input buffer based on
** the tokenization rules supplied by a specific sqlite3_tokenizer
** object.
*/
typedef struct sqlite3_tokenizer_module sqlite3_tokenizer_module;
typedef struct sqlite3_tokenizer sqlite3_tokenizer;
typedef struct sqlite3_tokenizer_cursor sqlite3_tokenizer_cursor;

struct sqlite3_tokenizer_module {

  /*
  ** Structure version. Should always be set to 0 or 1.
  */
  int iVersion;

  /*
  ** Create a new tokenizer. The values in the argv[] array are the
  ** arguments passed to the "tokenizer" clause of the CREATE VIRTUAL
  ** TABLE statement that created the fts3 table. For example, if
  ** the following SQL is executed:
  **
  **   CREATE .. USING fts3( ... , tokenizer <tokenizer-name> arg1 arg2)
  **
  ** then argc is set to 2, and the argv[] array contains pointers
  ** to the strings "arg1" and "arg2".
  **
  ** This method should return either SQLITE_OK (0), or an SQLite error
  ** code. If SQLITE_OK is returned, then *ppTokenizer should be set
  ** to point at the newly created tokenizer structure. The generic
  ** sqlite3_tokenizer.pModule variable should not be initialized by
  ** this callback. The caller will do so.
  */
  int (*xCreate)(
    int argc,                           /* Size of argv array */
    const char *const*argv,             /* Tokenizer argument strings */
    sqlite3_tokenizer **ppTokenizer     /* OUT: Created tokenizer */
  );

  /*
  ** Destroy an existing tokenizer. The fts3 module calls this method
  ** exactly once for each successful call to xCreate().
  */
  int (*xDestroy)(sqlite3_tokenizer *pTokenizer);

  /*
  ** Create a tokenizer cursor to tokenize an input buffer. The caller
  ** is responsible for ensuring that the input buffer remains valid
  ** until the cursor is closed (using the xClose() method).
  */
  int (*xOpen)(
    sqlite3_tokenizer *pTokenizer,       /* Tokenizer object */
    const char *pInput, int nBytes,      /* Input buffer */
    sqlite3_tokenizer_cursor **ppCursor  /* OUT: Created tokenizer cursor */
  );

  /*
  ** Destroy an existing tokenizer cursor. The fts3 module calls this
  ** method exactly once for each successful call to xOpen().
  */
  int (*xClose)(sqlite3_tokenizer_cursor *pCursor);

  /*
  ** Retrieve the next token from the tokenizer cursor pCursor. This
  ** method should either return SQLITE_OK and set the values of the
  ** "OUT" variables identified below, or SQLITE_DONE to indicate that
  ** the end of the buffer has been reached, or an SQLite error code.
  **
  ** *ppToken should be set to point at a buffer containing the
  ** normalized version of the token (i.e. after any case-folding and/or
  ** stemming has been performed). *pnBytes should be set to the length
  ** of this buffer in bytes. The input text that generated the token is
  ** identified by the byte offsets returned in *piStartOffset and
  ** *piEndOffset. *piStartOffset should be set to the index of the first
  ** byte of the token in the input buffer. *piEndOffset should be set
  ** to the index of the first byte just past the end of the token in
  ** the input buffer.
  **
  ** The buffer *ppToken is set to point at is managed by the tokenizer
  ** implementation. It is only required to be valid until the next call
  ** to xNext() or xClose().
  */
  /* TODO(shess) current implementation requires pInput to be
  ** nul-terminated.  This should either be fixed, or pInput/nBytes
  ** should be converted to zInput.
  */
  int (*xNext)(
    sqlite3_tokenizer_cursor *pCursor,   /* Tokenizer cursor */
    const char **ppToken, int *pnBytes,  /* OUT: Normalized text for token */
    int *piStartOffset,  /* OUT: Byte offset of token in input buffer */
    int *piEndOffset,    /* OUT: Byte offset of end of token in input buffer */
    int *piPosition      /* OUT: Number of tokens returned before this one */
  );

  /***********************************************************************
  ** Methods below this point are only available if iVersion>=1.
  */

  /*
  ** Configure the language id of a tokenizer cursor.
  */
  int (*xLanguageid)(sqlite3_tokenizer_cursor *pCsr, int iLangid);
};

struct sqlite3_tokenizer {
  const sqlite3_tokenizer_module *pModule;  /* The module for this tokenizer */
  /* Tokenizer implementations will typically add additional fields */
};

struct sqlite3_tokenizer_cursor {
  sqlite3_tokenizer *pTokenizer;       /* Tokenizer for this cursor. */
  /* Tokenizer implementations will typically add additional fields */
};

int fts3_global_term_cnt(int iTerm, int iCol);
int fts3_term_cnt(int iTerm, int iCol);


#endif /* _FTS3_TOKENIZER_H_ */

/************** End of fts3_tokenizer.h **************************************/
/************** Continuing where we left off in fts3Int.h ********************/
/************** Include fts3_hash.h in the middle of fts3Int.h ***************/
/************** Begin file fts3_hash.h ***************************************/
/*
** 2001 September 22
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This is the header file for the generic hash-table implementation
** used in SQLite.  We've modified it slightly to serve as a standalone
** hash table implementation for the full-text indexing module.
**
*/
#ifndef _FTS3_HASH_H_
#define _FTS3_HASH_H_

/* Forward declarations of structures. */
typedef struct Fts3Hash Fts3Hash;
typedef struct Fts3HashElem Fts3HashElem;

/* A complete hash table is an instance of the following structure.
** The internals of this structure are intended to be opaque -- client
** code should not attempt to access or modify the fields of this structure
** directly.  Change this structure only by using the routines below.
** However, many of the "procedures" and "functions" for modifying and
** accessing this structure are really macros, so we can't really make
** this structure opaque.
*/
struct Fts3Hash {
  char keyClass;          /* HASH_INT, _POINTER, _STRING, _BINARY */
  char copyKey;           /* True if copy of key made on insert */
  int count;              /* Number of entries in this table */
  Fts3HashElem *first;    /* The first element of the array */
  int htsize;             /* Number of buckets in the hash table */
  struct _fts3ht {        /* the hash table */
    int count;               /* Number of entries with this hash */
    Fts3HashElem *chain;     /* Pointer to first entry with this hash */
  } *ht;
};

/* Each element in the hash table is an instance of the following
** structure.  All elements are stored on a single doubly-linked list.
**
** Again, this structure is intended to be opaque, but it can't really

sqlite3.c  view on Meta::CPAN

  sqlite3_blob *pSegments;        /* Blob handle open on %_segments table */
  int iSavepoint;

  /*
  ** The following array of hash tables is used to buffer pending index
  ** updates during transactions. All pending updates buffered at any one
  ** time must share a common language-id (see the FTS4 langid= feature).
  ** The current language id is stored in variable iPrevLangid.
  **
  ** A single FTS4 table may have multiple full-text indexes. For each index
  ** there is an entry in the aIndex[] array. Index 0 is an index of all the
  ** terms that appear in the document set. Each subsequent index in aIndex[]
  ** is an index of prefixes of a specific length.
  **
  ** Variable nPendingData contains an estimate the memory consumed by the
  ** pending data structures, including hash table overhead, but not including
  ** malloc overhead.  When nPendingData exceeds nMaxPendingData, all hash
  ** tables are flushed to disk. Variable iPrevDocid is the docid of the most
  ** recently inserted record.
  */
  int nIndex;                     /* Size of aIndex[] */
  struct Fts3Index {
    int nPrefix;                  /* Prefix length (0 for main terms index) */
    Fts3Hash hPending;            /* Pending terms table for this index */
  } *aIndex;
  int nMaxPendingData;            /* Max pending data before flush to disk */
  int nPendingData;               /* Current bytes of pending data */
  sqlite_int64 iPrevDocid;        /* Docid of most recently inserted document */
  int iPrevLangid;                /* Langid of recently inserted document */
  int bPrevDelete;                /* True if last operation was a delete */

#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
  /* State variables used for validating that the transaction control
  ** methods of the virtual table are called at appropriate times.  These
  ** values do not contribute to FTS functionality; they are used for
  ** verifying the operation of the SQLite core.
  */
  int inTransaction;     /* True after xBegin but before xCommit/xRollback */
  int mxSavepoint;       /* Largest valid xSavepoint integer */
#endif

#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
  /* True to disable the incremental doclist optimization. This is controlled
  ** by special insert command 'test-no-incr-doclist'.  */
  int bNoIncrDoclist;

  /* Number of segments in a level */
  int nMergeCount;
#endif
};

/* Macro to find the number of segments to merge */
#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
# define MergeCount(P) ((P)->nMergeCount)
#else
# define MergeCount(P) FTS3_MERGE_COUNT
#endif

/*
** When the core wants to read from the virtual table, it creates a
** virtual table cursor (an instance of the following structure) using
** the xOpen method. Cursors are destroyed using the xClose method.
*/
struct Fts3Cursor {
  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
  i16 eSearch;                    /* Search strategy (see below) */
  u8 isEof;                       /* True if at End Of Results */
  u8 isRequireSeek;               /* True if must seek pStmt to %_content row */
  u8 bSeekStmt;                   /* True if pStmt is a seek */
  sqlite3_stmt *pStmt;            /* Prepared statement in use by the cursor */
  Fts3Expr *pExpr;                /* Parsed MATCH query string */
  int iLangid;                    /* Language being queried for */
  int nPhrase;                    /* Number of matchable phrases in query */
  Fts3DeferredToken *pDeferred;   /* Deferred search tokens, if any */
  sqlite3_int64 iPrevId;          /* Previous id read from aDoclist */
  char *pNextId;                  /* Pointer into the body of aDoclist */
  char *aDoclist;                 /* List of docids for full-text queries */
  int nDoclist;                   /* Size of buffer at aDoclist */
  u8 bDesc;                       /* True to sort in descending order */
  int eEvalmode;                  /* An FTS3_EVAL_XX constant */
  int nRowAvg;                    /* Average size of database rows, in pages */
  sqlite3_int64 nDoc;             /* Documents in table */
  i64 iMinDocid;                  /* Minimum docid to return */
  i64 iMaxDocid;                  /* Maximum docid to return */
  int isMatchinfoNeeded;          /* True when aMatchinfo[] needs filling in */
  MatchinfoBuffer *pMIBuffer;     /* Buffer for matchinfo data */
};

#define FTS3_EVAL_FILTER    0
#define FTS3_EVAL_NEXT      1
#define FTS3_EVAL_MATCHINFO 2

/*
** The Fts3Cursor.eSearch member is always set to one of the following.
** Actually, Fts3Cursor.eSearch can be greater than or equal to
** FTS3_FULLTEXT_SEARCH.  If so, then Fts3Cursor.eSearch - 2 is the index
** of the column to be searched.  For example, in
**
**     CREATE VIRTUAL TABLE ex1 USING fts3(a,b,c,d);
**     SELECT docid FROM ex1 WHERE b MATCH 'one two three';
**
** Because the LHS of the MATCH operator is 2nd column "b",
** Fts3Cursor.eSearch will be set to FTS3_FULLTEXT_SEARCH+1.  (+0 for a,
** +1 for b, +2 for c, +3 for d.)  If the LHS of MATCH were "ex1"
** indicating that all columns should be searched,
** then eSearch would be set to FTS3_FULLTEXT_SEARCH+4.
*/
#define FTS3_FULLSCAN_SEARCH 0    /* Linear scan of %_content table */
#define FTS3_DOCID_SEARCH    1    /* Lookup by rowid on %_content table */
#define FTS3_FULLTEXT_SEARCH 2    /* Full-text index search */

/*
** The lower 16-bits of the sqlite3_index_info.idxNum value set by
** the xBestIndex() method contains the Fts3Cursor.eSearch value described
** above. The upper 16-bits contain a combination of the following
** bits, used to describe extra constraints on full-text searches.
*/
#define FTS3_HAVE_LANGID    0x00010000      /* languageid=? */
#define FTS3_HAVE_DOCID_GE  0x00020000      /* docid>=? */
#define FTS3_HAVE_DOCID_LE  0x00040000      /* docid<=? */

struct Fts3Doclist {
  char *aAll;                    /* Array containing doclist (or NULL) */
  int nAll;                      /* Size of a[] in bytes */
  char *pNextDocid;              /* Pointer to next docid */

  sqlite3_int64 iDocid;          /* Current docid (if pList!=0) */
  int bFreeList;                 /* True if pList should be sqlite3_free()d */
  char *pList;                   /* Pointer to position list following iDocid */
  int nList;                     /* Length of position list */

sqlite3.c  view on Meta::CPAN

  int nCost;                      /* Cost of running iterator */
  int bLookup;                    /* True if a lookup of a single entry. */

  /* Output values. Valid only after Fts3SegReaderStep() returns SQLITE_ROW. */
  char *zTerm;                    /* Pointer to term buffer */
  int nTerm;                      /* Size of zTerm in bytes */
  char *aDoclist;                 /* Pointer to doclist buffer */
  int nDoclist;                   /* Size of aDoclist[] in bytes */
};

SQLITE_PRIVATE int sqlite3Fts3Incrmerge(Fts3Table*,int,int);

#define fts3GetVarint32(p, piVal) (                                           \
  (*(u8*)(p)&0x80) ? sqlite3Fts3GetVarint32(p, piVal) : (*piVal=*(u8*)(p), 1) \
)

/* fts3.c */
SQLITE_PRIVATE void sqlite3Fts3ErrMsg(char**,const char*,...);
SQLITE_PRIVATE int sqlite3Fts3PutVarint(char *, sqlite3_int64);
SQLITE_PRIVATE int sqlite3Fts3GetVarint(const char *, sqlite_int64 *);
SQLITE_PRIVATE int sqlite3Fts3GetVarintU(const char *, sqlite_uint64 *);
SQLITE_PRIVATE int sqlite3Fts3GetVarintBounded(const char*,const char*,sqlite3_int64*);
SQLITE_PRIVATE int sqlite3Fts3GetVarint32(const char *, int *);
SQLITE_PRIVATE int sqlite3Fts3VarintLen(sqlite3_uint64);
SQLITE_PRIVATE void sqlite3Fts3Dequote(char *);
SQLITE_PRIVATE void sqlite3Fts3DoclistPrev(int,char*,int,char**,sqlite3_int64*,int*,u8*);
SQLITE_PRIVATE int sqlite3Fts3EvalPhraseStats(Fts3Cursor *, Fts3Expr *, u32 *);
SQLITE_PRIVATE int sqlite3Fts3FirstFilter(sqlite3_int64, char *, int, char *);
SQLITE_PRIVATE void sqlite3Fts3CreateStatTable(int*, Fts3Table*);
SQLITE_PRIVATE int sqlite3Fts3EvalTestDeferred(Fts3Cursor *pCsr, int *pRc);
SQLITE_PRIVATE int sqlite3Fts3ReadInt(const char *z, int *pnOut);

/* fts3_tokenizer.c */
SQLITE_PRIVATE const char *sqlite3Fts3NextToken(const char *, int *);
SQLITE_PRIVATE int sqlite3Fts3InitHashTable(sqlite3 *, Fts3Hash *, const char *);
SQLITE_PRIVATE int sqlite3Fts3InitTokenizer(Fts3Hash *pHash, const char *,
    sqlite3_tokenizer **, char **
);
SQLITE_PRIVATE int sqlite3Fts3IsIdChar(char);

/* fts3_snippet.c */
SQLITE_PRIVATE void sqlite3Fts3Offsets(sqlite3_context*, Fts3Cursor*);
SQLITE_PRIVATE void sqlite3Fts3Snippet(sqlite3_context *, Fts3Cursor *, const char *,
  const char *, const char *, int, int
);
SQLITE_PRIVATE void sqlite3Fts3Matchinfo(sqlite3_context *, Fts3Cursor *, const char *);
SQLITE_PRIVATE void sqlite3Fts3MIBufferFree(MatchinfoBuffer *p);

/* fts3_expr.c */
SQLITE_PRIVATE int sqlite3Fts3ExprParse(sqlite3_tokenizer *, int,
  char **, int, int, int, const char *, int, Fts3Expr **, char **
);
SQLITE_PRIVATE void sqlite3Fts3ExprFree(Fts3Expr *);
#ifdef SQLITE_TEST
SQLITE_PRIVATE int sqlite3Fts3ExprInitTestInterface(sqlite3 *db, Fts3Hash*);
SQLITE_PRIVATE int sqlite3Fts3InitTerm(sqlite3 *db);
#endif
SQLITE_PRIVATE void *sqlite3Fts3MallocZero(i64 nByte);

SQLITE_PRIVATE int sqlite3Fts3OpenTokenizer(sqlite3_tokenizer *, int, const char *, int,
  sqlite3_tokenizer_cursor **
);

/* fts3_aux.c */
SQLITE_PRIVATE int sqlite3Fts3InitAux(sqlite3 *db);

SQLITE_PRIVATE void sqlite3Fts3EvalPhraseCleanup(Fts3Phrase *);

SQLITE_PRIVATE int sqlite3Fts3MsrIncrStart(
    Fts3Table*, Fts3MultiSegReader*, int, const char*, int);
SQLITE_PRIVATE int sqlite3Fts3MsrIncrNext(
    Fts3Table *, Fts3MultiSegReader *, sqlite3_int64 *, char **, int *);
SQLITE_PRIVATE int sqlite3Fts3EvalPhrasePoslist(Fts3Cursor *, Fts3Expr *, int iCol, char **);
SQLITE_PRIVATE int sqlite3Fts3MsrOvfl(Fts3Cursor *, Fts3MultiSegReader *, int *);
SQLITE_PRIVATE int sqlite3Fts3MsrIncrRestart(Fts3MultiSegReader *pCsr);
SQLITE_PRIVATE int sqlite3Fts3MsrCancel(Fts3Cursor*, Fts3Expr*);

/* fts3_tokenize_vtab.c */
SQLITE_PRIVATE int sqlite3Fts3InitTok(sqlite3*, Fts3Hash *, void(*xDestroy)(void*));

/* fts3_unicode2.c (functions generated by parsing unicode text files) */
#ifndef SQLITE_DISABLE_FTS3_UNICODE
SQLITE_PRIVATE int sqlite3FtsUnicodeFold(int, int);
SQLITE_PRIVATE int sqlite3FtsUnicodeIsalnum(int);
SQLITE_PRIVATE int sqlite3FtsUnicodeIsdiacritic(int);
#endif

SQLITE_PRIVATE int sqlite3Fts3ExprIterate(Fts3Expr*, int (*x)(Fts3Expr*,int,void*), void*);

SQLITE_PRIVATE int sqlite3Fts3IntegrityCheck(Fts3Table *p, int *pbOk);

#endif /* !SQLITE_CORE || SQLITE_ENABLE_FTS3 */
#endif /* _FTSINT_H */

/************** End of fts3Int.h *********************************************/
/************** Continuing where we left off in fts3.c ***********************/
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)

#if defined(SQLITE_ENABLE_FTS3) && !defined(SQLITE_CORE)
# define SQLITE_CORE 1
#endif


/* #include "fts3.h" */
#ifndef SQLITE_CORE
/* # include "sqlite3ext.h" */
  SQLITE_EXTENSION_INIT1
#endif

typedef struct Fts3HashWrapper Fts3HashWrapper;
struct Fts3HashWrapper {
  Fts3Hash hash;                  /* Hash table */
  int nRef;                       /* Number of pointers to this object */
};

static int fts3EvalNext(Fts3Cursor *pCsr);
static int fts3EvalStart(Fts3Cursor *pCsr);
static int fts3TermSegReaderCursor(
    Fts3Cursor *, const char *, int, int, Fts3MultiSegReader **);

/*

sqlite3.c  view on Meta::CPAN

    }

    if( bDocid ){
      switch( pCons->op ){
        case SQLITE_INDEX_CONSTRAINT_GE:
        case SQLITE_INDEX_CONSTRAINT_GT:
          iDocidGe = i;
          break;

        case SQLITE_INDEX_CONSTRAINT_LE:
        case SQLITE_INDEX_CONSTRAINT_LT:
          iDocidLe = i;
          break;
      }
    }
  }

  /* If using a docid=? or rowid=? strategy, set the UNIQUE flag. */
  if( pInfo->idxNum==FTS3_DOCID_SEARCH ) fts3SetUniqueFlag(pInfo);

  iIdx = 1;
  if( iCons>=0 ){
    pInfo->aConstraintUsage[iCons].argvIndex = iIdx++;
    pInfo->aConstraintUsage[iCons].omit = 1;
  }
  if( iLangidCons>=0 ){
    pInfo->idxNum |= FTS3_HAVE_LANGID;
    pInfo->aConstraintUsage[iLangidCons].argvIndex = iIdx++;
  }
  if( iDocidGe>=0 ){
    pInfo->idxNum |= FTS3_HAVE_DOCID_GE;
    pInfo->aConstraintUsage[iDocidGe].argvIndex = iIdx++;
  }
  if( iDocidLe>=0 ){
    pInfo->idxNum |= FTS3_HAVE_DOCID_LE;
    pInfo->aConstraintUsage[iDocidLe].argvIndex = iIdx++;
  }

  /* Regardless of the strategy selected, FTS can deliver rows in rowid (or
  ** docid) order. Both ascending and descending are possible.
  */
  if( pInfo->nOrderBy==1 ){
    struct sqlite3_index_orderby *pOrder = &pInfo->aOrderBy[0];
    if( pOrder->iColumn<0 || pOrder->iColumn==p->nColumn+1 ){
      if( pOrder->desc ){
        pInfo->idxStr = "DESC";
      }else{
        pInfo->idxStr = "ASC";
      }
      pInfo->orderByConsumed = 1;
    }
  }

  assert( p->pSegments==0 );
  return SQLITE_OK;
}

/*
** Implementation of xOpen method.
*/
static int fts3OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
  sqlite3_vtab_cursor *pCsr;               /* Allocated cursor */

  UNUSED_PARAMETER(pVTab);

  /* Allocate a buffer large enough for an Fts3Cursor structure. If the
  ** allocation succeeds, zero it and return SQLITE_OK. Otherwise,
  ** if the allocation fails, return SQLITE_NOMEM.
  */
  *ppCsr = pCsr = (sqlite3_vtab_cursor *)sqlite3_malloc(sizeof(Fts3Cursor));
  if( !pCsr ){
    return SQLITE_NOMEM;
  }
  memset(pCsr, 0, sizeof(Fts3Cursor));
  return SQLITE_OK;
}

/*
** Finalize the statement handle at pCsr->pStmt.
**
** Or, if that statement handle is one created by fts3CursorSeekStmt(),
** and the Fts3Table.pSeekStmt slot is currently NULL, save the statement
** pointer there instead of finalizing it.
*/
static void fts3CursorFinalizeStmt(Fts3Cursor *pCsr){
  if( pCsr->bSeekStmt ){
    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
    if( p->pSeekStmt==0 ){
      p->pSeekStmt = pCsr->pStmt;
      sqlite3_reset(pCsr->pStmt);
      pCsr->pStmt = 0;
    }
    pCsr->bSeekStmt = 0;
  }
  sqlite3_finalize(pCsr->pStmt);
}

/*
** Free all resources currently held by the cursor passed as the only
** argument.
*/
static void fts3ClearCursor(Fts3Cursor *pCsr){
  fts3CursorFinalizeStmt(pCsr);
  sqlite3Fts3FreeDeferredTokens(pCsr);
  sqlite3_free(pCsr->aDoclist);
  sqlite3Fts3MIBufferFree(pCsr->pMIBuffer);
  sqlite3Fts3ExprFree(pCsr->pExpr);
  memset(&(&pCsr->base)[1], 0, sizeof(Fts3Cursor)-sizeof(sqlite3_vtab_cursor));
}

/*
** Close the cursor.  For additional information see the documentation
** on the xClose method of the virtual table interface.
*/
static int fts3CloseMethod(sqlite3_vtab_cursor *pCursor){
  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
  fts3ClearCursor(pCsr);
  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

/*
** If pCsr->pStmt has not been prepared (i.e. if pCsr->pStmt==0), then
** compose and prepare an SQL statement of the form:
**
**    "SELECT <columns> FROM %_content WHERE rowid = ?"
**
** (or the equivalent for a content=xxx table) and set pCsr->pStmt to
** it. If an error occurs, return an SQLite error code.
*/
static int fts3CursorSeekStmt(Fts3Cursor *pCsr){
  int rc = SQLITE_OK;
  if( pCsr->pStmt==0 ){
    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
    char *zSql;
    if( p->pSeekStmt ){
      pCsr->pStmt = p->pSeekStmt;
      p->pSeekStmt = 0;
    }else{
      zSql = sqlite3_mprintf("SELECT %s WHERE rowid = ?", p->zReadExprlist);
      if( !zSql ) return SQLITE_NOMEM;
      p->bLock++;
      rc = sqlite3_prepare_v3(
          p->db, zSql,-1,SQLITE_PREPARE_PERSISTENT,&pCsr->pStmt,0
      );
      p->bLock--;
      sqlite3_free(zSql);
    }
    if( rc==SQLITE_OK ) pCsr->bSeekStmt = 1;
  }
  return rc;
}

/*
** Position the pCsr->pStmt statement so that it is on the row
** of the %_content table that contains the last match.  Return
** SQLITE_OK on success.
*/
static int fts3CursorSeek(sqlite3_context *pContext, Fts3Cursor *pCsr){
  int rc = SQLITE_OK;
  if( pCsr->isRequireSeek ){
    rc = fts3CursorSeekStmt(pCsr);
    if( rc==SQLITE_OK ){
      Fts3Table *pTab = (Fts3Table*)pCsr->base.pVtab;
      pTab->bLock++;
      sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iPrevId);
      pCsr->isRequireSeek = 0;
      if( SQLITE_ROW==sqlite3_step(pCsr->pStmt) ){
        pTab->bLock--;
        return SQLITE_OK;
      }else{
        pTab->bLock--;
        rc = sqlite3_reset(pCsr->pStmt);

sqlite3.c  view on Meta::CPAN

  int rc = SQLITE_OK;             /* Error code */
  sqlite3_stmt *pStmt = 0;        /* Statement to iterate through segments */
  int rc2;                        /* Result of sqlite3_reset() */

  /* If iLevel is less than 0 and this is not a scan, include a seg-reader
  ** for the pending-terms. If this is a scan, then this call must be being
  ** made by an fts4aux module, not an FTS table. In this case calling
  ** Fts3SegReaderPending might segfault, as the data structures used by
  ** fts4aux are not completely populated. So it's easiest to filter these
  ** calls out here.  */
  if( iLevel<0 && p->aIndex && p->iPrevLangid==iLangid ){
    Fts3SegReader *pSeg = 0;
    rc = sqlite3Fts3SegReaderPending(p, iIndex, zTerm, nTerm, isPrefix||isScan, &pSeg);
    if( rc==SQLITE_OK && pSeg ){
      rc = fts3SegReaderCursorAppend(pCsr, pSeg);
    }
  }

  if( iLevel!=FTS3_SEGCURSOR_PENDING ){
    if( rc==SQLITE_OK ){
      rc = sqlite3Fts3AllSegdirs(p, iLangid, iIndex, iLevel, &pStmt);
    }

    while( rc==SQLITE_OK && SQLITE_ROW==(rc = sqlite3_step(pStmt)) ){
      Fts3SegReader *pSeg = 0;

      /* Read the values returned by the SELECT into local variables. */
      sqlite3_int64 iStartBlock = sqlite3_column_int64(pStmt, 1);
      sqlite3_int64 iLeavesEndBlock = sqlite3_column_int64(pStmt, 2);
      sqlite3_int64 iEndBlock = sqlite3_column_int64(pStmt, 3);
      int nRoot = sqlite3_column_bytes(pStmt, 4);
      char const *zRoot = sqlite3_column_blob(pStmt, 4);

      /* If zTerm is not NULL, and this segment is not stored entirely on its
      ** root node, the range of leaves scanned can be reduced. Do this. */
      if( iStartBlock && zTerm && zRoot ){
        sqlite3_int64 *pi = (isPrefix ? &iLeavesEndBlock : 0);
        rc = fts3SelectLeaf(p, zTerm, nTerm, zRoot, nRoot, &iStartBlock, pi);
        if( rc!=SQLITE_OK ) goto finished;
        if( isPrefix==0 && isScan==0 ) iLeavesEndBlock = iStartBlock;
      }

      rc = sqlite3Fts3SegReaderNew(pCsr->nSegment+1,
          (isPrefix==0 && isScan==0),
          iStartBlock, iLeavesEndBlock,
          iEndBlock, zRoot, nRoot, &pSeg
      );
      if( rc!=SQLITE_OK ) goto finished;
      rc = fts3SegReaderCursorAppend(pCsr, pSeg);
    }
  }

 finished:
  rc2 = sqlite3_reset(pStmt);
  if( rc==SQLITE_DONE ) rc = rc2;

  return rc;
}

/*
** Set up a cursor object for iterating through a full-text index or a
** single level therein.
*/
SQLITE_PRIVATE int sqlite3Fts3SegReaderCursor(
  Fts3Table *p,                   /* FTS3 table handle */
  int iLangid,                    /* Language-id to search */
  int iIndex,                     /* Index to search (from 0 to p->nIndex-1) */
  int iLevel,                     /* Level of segments to scan */
  const char *zTerm,              /* Term to query for */
  int nTerm,                      /* Size of zTerm in bytes */
  int isPrefix,                   /* True for a prefix search */
  int isScan,                     /* True to scan from zTerm to EOF */
  Fts3MultiSegReader *pCsr       /* Cursor object to populate */
){
  assert( iIndex>=0 && iIndex<p->nIndex );
  assert( iLevel==FTS3_SEGCURSOR_ALL
      ||  iLevel==FTS3_SEGCURSOR_PENDING
      ||  iLevel>=0
  );
  assert( iLevel<FTS3_SEGDIR_MAXLEVEL );
  assert( FTS3_SEGCURSOR_ALL<0 && FTS3_SEGCURSOR_PENDING<0 );
  assert( isPrefix==0 || isScan==0 );

  memset(pCsr, 0, sizeof(Fts3MultiSegReader));
  return fts3SegReaderCursor(
      p, iLangid, iIndex, iLevel, zTerm, nTerm, isPrefix, isScan, pCsr
  );
}

/*
** In addition to its current configuration, have the Fts3MultiSegReader
** passed as the 4th argument also scan the doclist for term zTerm/nTerm.
**
** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
*/
static int fts3SegReaderCursorAddZero(
  Fts3Table *p,                   /* FTS virtual table handle */
  int iLangid,
  const char *zTerm,              /* Term to scan doclist of */
  int nTerm,                      /* Number of bytes in zTerm */
  Fts3MultiSegReader *pCsr        /* Fts3MultiSegReader to modify */
){
  return fts3SegReaderCursor(p,
      iLangid, 0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0,pCsr
  );
}

/*
** Open an Fts3MultiSegReader to scan the doclist for term zTerm/nTerm. Or,
** if isPrefix is true, to scan the doclist for all terms for which
** zTerm/nTerm is a prefix. If successful, return SQLITE_OK and write
** a pointer to the new Fts3MultiSegReader to *ppSegcsr. Otherwise, return
** an SQLite error code.
**
** It is the responsibility of the caller to free this object by eventually
** passing it to fts3SegReaderCursorFree()
**
** SQLITE_OK is returned if no error occurs, otherwise an SQLite error code.
** Output parameter *ppSegcsr is set to 0 if an error occurs.
*/
static int fts3TermSegReaderCursor(
  Fts3Cursor *pCsr,               /* Virtual table cursor handle */
  const char *zTerm,              /* Term to query for */
  int nTerm,                      /* Size of zTerm in bytes */
  int isPrefix,                   /* True for a prefix search */
  Fts3MultiSegReader **ppSegcsr   /* OUT: Allocated seg-reader cursor */
){
  Fts3MultiSegReader *pSegcsr;    /* Object to allocate and return */
  int rc = SQLITE_NOMEM;          /* Return code */

  pSegcsr = sqlite3_malloc(sizeof(Fts3MultiSegReader));
  if( pSegcsr ){
    int i;
    int bFound = 0;               /* True once an index has been found */
    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;

    if( isPrefix ){
      for(i=1; bFound==0 && i<p->nIndex; i++){
        if( p->aIndex[i].nPrefix==nTerm ){
          bFound = 1;
          rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid,
              i, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 0, 0, pSegcsr
          );
          pSegcsr->bLookup = 1;
        }
      }

      for(i=1; bFound==0 && i<p->nIndex; i++){
        if( p->aIndex[i].nPrefix==nTerm+1 ){
          bFound = 1;
          rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid,
              i, FTS3_SEGCURSOR_ALL, zTerm, nTerm, 1, 0, pSegcsr
          );
          if( rc==SQLITE_OK ){
            rc = fts3SegReaderCursorAddZero(
                p, pCsr->iLangid, zTerm, nTerm, pSegcsr
            );
          }
        }
      }
    }

    if( bFound==0 ){
      rc = sqlite3Fts3SegReaderCursor(p, pCsr->iLangid,
          0, FTS3_SEGCURSOR_ALL, zTerm, nTerm, isPrefix, 0, pSegcsr
      );
      pSegcsr->bLookup = !isPrefix;
    }
  }

  *ppSegcsr = pSegcsr;
  return rc;
}

/*
** Free an Fts3MultiSegReader allocated by fts3TermSegReaderCursor().
*/
static void fts3SegReaderCursorFree(Fts3MultiSegReader *pSegcsr){
  sqlite3Fts3SegReaderFinish(pSegcsr);
  sqlite3_free(pSegcsr);
}

/*
** This function retrieves the doclist for the specified term (or term
** prefix) from the database.
*/
static int fts3TermSelect(
  Fts3Table *p,                   /* Virtual table handle */
  Fts3PhraseToken *pTok,          /* Token to query for */
  int iColumn,                    /* Column to query (or -ve for all columns) */
  int *pnOut,                     /* OUT: Size of buffer at *ppOut */
  char **ppOut                    /* OUT: Malloced result buffer */
){
  int rc;                         /* Return code */
  Fts3MultiSegReader *pSegcsr;    /* Seg-reader cursor for this term */
  TermSelect tsc;                 /* Object for pair-wise doclist merging */
  Fts3SegFilter filter;           /* Segment term filter configuration */

  pSegcsr = pTok->pSegcsr;
  memset(&tsc, 0, sizeof(TermSelect));

  filter.flags = FTS3_SEGMENT_IGNORE_EMPTY | FTS3_SEGMENT_REQUIRE_POS
        | (pTok->isPrefix ? FTS3_SEGMENT_PREFIX : 0)
        | (pTok->bFirst ? FTS3_SEGMENT_FIRST : 0)
        | (iColumn<p->nColumn ? FTS3_SEGMENT_COLUMN_FILTER : 0);
  filter.iCol = iColumn;
  filter.zTerm = pTok->z;
  filter.nTerm = pTok->n;

  rc = sqlite3Fts3SegReaderStart(p, pSegcsr, &filter);
  while( SQLITE_OK==rc
      && SQLITE_ROW==(rc = sqlite3Fts3SegReaderStep(p, pSegcsr))
  ){
    rc = fts3TermSelectMerge(p, &tsc, pSegcsr->aDoclist, pSegcsr->nDoclist);
  }

  if( rc==SQLITE_OK ){
    rc = fts3TermSelectFinishMerge(p, &tsc);
  }
  if( rc==SQLITE_OK ){
    *ppOut = tsc.aaOutput[0];
    *pnOut = tsc.anOutput[0];
  }else{
    int i;
    for(i=0; i<SizeofArray(tsc.aaOutput); i++){
      sqlite3_free(tsc.aaOutput[i]);
    }
  }

  fts3SegReaderCursorFree(pSegcsr);
  pTok->pSegcsr = 0;
  return rc;
}

/*
** This function counts the total number of docids in the doclist stored
** in buffer aList[], size nList bytes.
**
** If the isPoslist argument is true, then it is assumed that the doclist
** contains a position-list following each docid. Otherwise, it is assumed
** that the doclist is simply a list of docids stored as delta encoded
** varints.
*/
static int fts3DoclistCountDocids(char *aList, int nList){
  int nDoc = 0;                   /* Return value */
  if( aList ){
    char *aEnd = &aList[nList];   /* Pointer to one byte after EOF */
    char *p = aList;              /* Cursor */
    while( p<aEnd ){
      nDoc++;
      while( (*p++)&0x80 );     /* Skip docid varint */
      fts3PoslistCopy(0, &p);   /* Skip over position list */
    }
  }

  return nDoc;
}

/*
** Advance the cursor to the next row in the %_content table that
** matches the search criteria.  For a MATCH search, this will be
** the next row that matches. For a full-table scan, this will be
** simply the next row in the %_content table.  For a docid lookup,
** this routine simply sets the EOF flag.
**
** Return SQLITE_OK if nothing goes wrong.  SQLITE_OK is returned
** even if we reach end-of-file.  The fts3EofMethod() will be called
** subsequently to determine whether or not an EOF was hit.
*/
static int fts3NextMethod(sqlite3_vtab_cursor *pCursor){
  int rc;
  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;
  if( pCsr->eSearch==FTS3_DOCID_SEARCH || pCsr->eSearch==FTS3_FULLSCAN_SEARCH ){
    Fts3Table *pTab = (Fts3Table*)pCursor->pVtab;
    pTab->bLock++;
    if( SQLITE_ROW!=sqlite3_step(pCsr->pStmt) ){
      pCsr->isEof = 1;
      rc = sqlite3_reset(pCsr->pStmt);
    }else{
      pCsr->iPrevId = sqlite3_column_int64(pCsr->pStmt, 0);
      rc = SQLITE_OK;
    }
    pTab->bLock--;
  }else{
    rc = fts3EvalNext((Fts3Cursor *)pCursor);
  }
  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
  return rc;
}

/*
** If the numeric type of argument pVal is "integer", then return it
** converted to a 64-bit signed integer. Otherwise, return a copy of
** the second parameter, iDefault.
*/
static sqlite3_int64 fts3DocidRange(sqlite3_value *pVal, i64 iDefault){
  if( pVal ){
    int eType = sqlite3_value_numeric_type(pVal);
    if( eType==SQLITE_INTEGER ){
      return sqlite3_value_int64(pVal);
    }
  }
  return iDefault;
}

/*
** This is the xFilter interface for the virtual table.  See
** the virtual table xFilter method documentation for additional
** information.
**
** If idxNum==FTS3_FULLSCAN_SEARCH then do a full table scan against
** the %_content table.
**
** If idxNum==FTS3_DOCID_SEARCH then do a docid lookup for a single entry
** in the %_content table.
**
** If idxNum>=FTS3_FULLTEXT_SEARCH then use the full text index.  The
** column on the left-hand side of the MATCH operator is column
** number idxNum-FTS3_FULLTEXT_SEARCH, 0 indexed.  argv[0] is the right-hand
** side of the MATCH operator.
*/
static int fts3FilterMethod(
  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
  int idxNum,                     /* Strategy index */
  const char *idxStr,             /* Unused */
  int nVal,                       /* Number of elements in apVal */
  sqlite3_value **apVal           /* Arguments for the indexing scheme */
){
  int rc = SQLITE_OK;
  char *zSql;                     /* SQL statement used to access %_content */
  int eSearch;
  Fts3Table *p = (Fts3Table *)pCursor->pVtab;
  Fts3Cursor *pCsr = (Fts3Cursor *)pCursor;

  sqlite3_value *pCons = 0;       /* The MATCH or rowid constraint, if any */
  sqlite3_value *pLangid = 0;     /* The "langid = ?" constraint, if any */
  sqlite3_value *pDocidGe = 0;    /* The "docid >= ?" constraint, if any */
  sqlite3_value *pDocidLe = 0;    /* The "docid <= ?" constraint, if any */
  int iIdx;

  UNUSED_PARAMETER(idxStr);
  UNUSED_PARAMETER(nVal);

  if( p->bLock ){
    return SQLITE_ERROR;
  }

  eSearch = (idxNum & 0x0000FFFF);
  assert( eSearch>=0 && eSearch<=(FTS3_FULLTEXT_SEARCH+p->nColumn) );
  assert( p->pSegments==0 );

  /* Collect arguments into local variables */
  iIdx = 0;
  if( eSearch!=FTS3_FULLSCAN_SEARCH ) pCons = apVal[iIdx++];
  if( idxNum & FTS3_HAVE_LANGID ) pLangid = apVal[iIdx++];
  if( idxNum & FTS3_HAVE_DOCID_GE ) pDocidGe = apVal[iIdx++];
  if( idxNum & FTS3_HAVE_DOCID_LE ) pDocidLe = apVal[iIdx++];
  assert( iIdx==nVal );

  /* In case the cursor has been used before, clear it now. */
  fts3ClearCursor(pCsr);

  /* Set the lower and upper bounds on docids to return */
  pCsr->iMinDocid = fts3DocidRange(pDocidGe, SMALLEST_INT64);
  pCsr->iMaxDocid = fts3DocidRange(pDocidLe, LARGEST_INT64);

  if( idxStr ){
    pCsr->bDesc = (idxStr[0]=='D');
  }else{
    pCsr->bDesc = p->bDescIdx;
  }
  pCsr->eSearch = (i16)eSearch;

  if( eSearch!=FTS3_DOCID_SEARCH && eSearch!=FTS3_FULLSCAN_SEARCH ){
    int iCol = eSearch-FTS3_FULLTEXT_SEARCH;
    const char *zQuery = (const char *)sqlite3_value_text(pCons);

    if( zQuery==0 && sqlite3_value_type(pCons)!=SQLITE_NULL ){
      return SQLITE_NOMEM;
    }

    pCsr->iLangid = 0;
    if( pLangid ) pCsr->iLangid = sqlite3_value_int(pLangid);

    assert( p->base.zErrMsg==0 );
    rc = sqlite3Fts3ExprParse(p->pTokenizer, pCsr->iLangid,
        p->azColumn, p->bFts4, p->nColumn, iCol, zQuery, -1, &pCsr->pExpr,
        &p->base.zErrMsg
    );
    if( rc!=SQLITE_OK ){
      return rc;
    }

    rc = fts3EvalStart(pCsr);
    sqlite3Fts3SegmentsClose(p);
    if( rc!=SQLITE_OK ) return rc;
    pCsr->pNextId = pCsr->aDoclist;
    pCsr->iPrevId = 0;
  }

  /* Compile a SELECT statement for this cursor. For a full-table-scan, the
  ** statement loops through all rows of the %_content table. For a
  ** full-text query or docid lookup, the statement retrieves a single
  ** row by docid.
  */
  if( eSearch==FTS3_FULLSCAN_SEARCH ){
    if( pDocidGe || pDocidLe ){
      zSql = sqlite3_mprintf(
          "SELECT %s WHERE rowid BETWEEN %lld AND %lld ORDER BY rowid %s",
          p->zReadExprlist, pCsr->iMinDocid, pCsr->iMaxDocid,
          (pCsr->bDesc ? "DESC" : "ASC")
      );
    }else{
      zSql = sqlite3_mprintf("SELECT %s ORDER BY rowid %s",
          p->zReadExprlist, (pCsr->bDesc ? "DESC" : "ASC")
      );
    }
    if( zSql ){
      p->bLock++;
      rc = sqlite3_prepare_v3(
          p->db,zSql,-1,SQLITE_PREPARE_PERSISTENT,&pCsr->pStmt,0
      );
      p->bLock--;
      sqlite3_free(zSql);
    }else{
      rc = SQLITE_NOMEM;
    }
  }else if( eSearch==FTS3_DOCID_SEARCH ){
    rc = fts3CursorSeekStmt(pCsr);
    if( rc==SQLITE_OK ){
      rc = sqlite3_bind_value(pCsr->pStmt, 1, pCons);
    }
  }
  if( rc!=SQLITE_OK ) return rc;

  return fts3NextMethod(pCursor);
}

/*
** This is the xEof method of the virtual table. SQLite calls this
** routine to find out if it has reached the end of a result set.
*/
static int fts3EofMethod(sqlite3_vtab_cursor *pCursor){
  Fts3Cursor *pCsr = (Fts3Cursor*)pCursor;
  if( pCsr->isEof ){
    fts3ClearCursor(pCsr);
    pCsr->isEof = 1;
  }
  return pCsr->isEof;
}

/*
** This is the xRowid method. The SQLite core calls this routine to
** retrieve the rowid for the current row of the result set. fts3
** exposes %_content.docid as the rowid for the virtual table. The
** rowid should be written to *pRowid.
*/
static int fts3RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
  Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;
  *pRowid = pCsr->iPrevId;
  return SQLITE_OK;
}

/*
** This is the xColumn method, called by SQLite to request a value from
** the row that the supplied cursor currently points to.
**
** If:
**
**   (iCol <  p->nColumn)   -> The value of the iCol'th user column.
**   (iCol == p->nColumn)   -> Magic column with the same name as the table.
**   (iCol == p->nColumn+1) -> Docid column
**   (iCol == p->nColumn+2) -> Langid column
*/
static int fts3ColumnMethod(
  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
  int iCol                        /* Index of column to read value from */
){
  int rc = SQLITE_OK;             /* Return Code */
  Fts3Cursor *pCsr = (Fts3Cursor *) pCursor;
  Fts3Table *p = (Fts3Table *)pCursor->pVtab;

  /* The column value supplied by SQLite must be in range. */
  assert( iCol>=0 && iCol<=p->nColumn+2 );

  switch( iCol-p->nColumn ){
    case 0:
      /* The special 'table-name' column */
      sqlite3_result_pointer(pCtx, pCsr, "fts3cursor", 0);
      break;

    case 1:
      /* The docid column */
      sqlite3_result_int64(pCtx, pCsr->iPrevId);
      break;

    case 2:
      if( pCsr->pExpr ){
        sqlite3_result_int64(pCtx, pCsr->iLangid);
        break;
      }else if( p->zLanguageid==0 ){
        sqlite3_result_int(pCtx, 0);
        break;
      }else{
        iCol = p->nColumn;
        /* no break */ deliberate_fall_through
      }

    default:
      /* A user column. Or, if this is a full-table scan, possibly the
      ** language-id column. Seek the cursor. */
      rc = fts3CursorSeek(0, pCsr);
      if( rc==SQLITE_OK && sqlite3_data_count(pCsr->pStmt)-1>iCol ){
        sqlite3_result_value(pCtx, sqlite3_column_value(pCsr->pStmt, iCol+1));
      }
      break;
  }

  assert( ((Fts3Table *)pCsr->base.pVtab)->pSegments==0 );
  return rc;
}

/*
** This function is the implementation of the xUpdate callback used by
** FTS3 virtual tables. It is invoked by SQLite each time a row is to be
** inserted, updated or deleted.
*/
static int fts3UpdateMethod(
  sqlite3_vtab *pVtab,            /* Virtual table handle */
  int nArg,                       /* Size of argument array */
  sqlite3_value **apVal,          /* Array of arguments */
  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
){
  return sqlite3Fts3UpdateMethod(pVtab, nArg, apVal, pRowid);
}

/*
** Implementation of xSync() method. Flush the contents of the pending-terms
** hash-table to the database.
*/
static int fts3SyncMethod(sqlite3_vtab *pVtab){

  /* Following an incremental-merge operation, assuming that the input
  ** segments are not completely consumed (the usual case), they are updated
  ** in place to remove the entries that have already been merged. This
  ** involves updating the leaf block that contains the smallest unmerged
  ** entry and each block (if any) between the leaf and the root node. So
  ** if the height of the input segment b-trees is N, and input segments
  ** are merged eight at a time, updating the input segments at the end
  ** of an incremental-merge requires writing (8*(1+N)) blocks. N is usually
  ** small - often between 0 and 2. So the overhead of the incremental
  ** merge is somewhere between 8 and 24 blocks. To avoid this overhead
  ** dwarfing the actual productive work accomplished, the incremental merge
  ** is only attempted if it will write at least 64 leaf blocks. Hence
  ** nMinMerge.
  **
  ** Of course, updating the input segments also involves deleting a bunch
  ** of blocks from the segments table. But this is not considered overhead
  ** as it would also be required by a crisis-merge that used the same input
  ** segments.
  */
  const u32 nMinMerge = 64;       /* Minimum amount of incr-merge work to do */

  Fts3Table *p = (Fts3Table*)pVtab;
  int rc;
  i64 iLastRowid = sqlite3_last_insert_rowid(p->db);

  rc = sqlite3Fts3PendingTermsFlush(p);
  if( rc==SQLITE_OK
   && p->nLeafAdd>(nMinMerge/16)
   && p->nAutoincrmerge && p->nAutoincrmerge!=0xff

sqlite3.c  view on Meta::CPAN

  sqlite3Fts3PendingTermsClear(p);
  assert( p->inTransaction!=0 );
  TESTONLY( p->inTransaction = 0 );
  TESTONLY( p->mxSavepoint = -1; );
  return SQLITE_OK;
}

/*
** When called, *ppPoslist must point to the byte immediately following the
** end of a position-list. i.e. ( (*ppPoslist)[-1]==POS_END ). This function
** moves *ppPoslist so that it instead points to the first byte of the
** same position list.
*/
static void fts3ReversePoslist(char *pStart, char **ppPoslist){
  char *p = &(*ppPoslist)[-2];
  char c = 0;

  /* Skip backwards passed any trailing 0x00 bytes added by NearTrim() */
  while( p>pStart && (c=*p--)==0 );

  /* Search backwards for a varint with value zero (the end of the previous
  ** poslist). This is an 0x00 byte preceded by some byte that does not
  ** have the 0x80 bit set.  */
  while( p>pStart && (*p & 0x80) | c ){
    c = *p--;
  }
  assert( p==pStart || c==0 );

  /* At this point p points to that preceding byte without the 0x80 bit
  ** set. So to find the start of the poslist, skip forward 2 bytes then
  ** over a varint.
  **
  ** Normally. The other case is that p==pStart and the poslist to return
  ** is the first in the doclist. In this case do not skip forward 2 bytes.
  ** The second part of the if condition (c==0 && *ppPoslist>&p[2])
  ** is required for cases where the first byte of a doclist and the
  ** doclist is empty. For example, if the first docid is 10, a doclist
  ** that begins with:
  **
  **   0x0A 0x00 <next docid delta varint>
  */
  if( p>pStart || (c==0 && *ppPoslist>&p[2]) ){ p = &p[2]; }
  while( *p++&0x80 );
  *ppPoslist = p;
}

/*
** Helper function used by the implementation of the overloaded snippet(),
** offsets() and optimize() SQL functions.
**
** If the value passed as the third argument is a blob of size
** sizeof(Fts3Cursor*), then the blob contents are copied to the
** output variable *ppCsr and SQLITE_OK is returned. Otherwise, an error
** message is written to context pContext and SQLITE_ERROR returned. The
** string passed via zFunc is used as part of the error message.
*/
static int fts3FunctionArg(
  sqlite3_context *pContext,      /* SQL function call context */
  const char *zFunc,              /* Function name */
  sqlite3_value *pVal,            /* argv[0] passed to function */
  Fts3Cursor **ppCsr              /* OUT: Store cursor handle here */
){
  int rc;
  *ppCsr = (Fts3Cursor*)sqlite3_value_pointer(pVal, "fts3cursor");
  if( (*ppCsr)!=0 ){
    rc = SQLITE_OK;
  }else{
    char *zErr = sqlite3_mprintf("illegal first argument to %s", zFunc);
    sqlite3_result_error(pContext, zErr, -1);
    sqlite3_free(zErr);
    rc = SQLITE_ERROR;
  }
  return rc;
}

/*
** Implementation of the snippet() function for FTS3
*/
static void fts3SnippetFunc(
  sqlite3_context *pContext,      /* SQLite function call context */
  int nVal,                       /* Size of apVal[] array */
  sqlite3_value **apVal           /* Array of arguments */
){
  Fts3Cursor *pCsr;               /* Cursor handle passed through apVal[0] */
  const char *zStart = "<b>";
  const char *zEnd = "</b>";
  const char *zEllipsis = "<b>...</b>";
  int iCol = -1;
  int nToken = 15;                /* Default number of tokens in snippet */

  /* There must be at least one argument passed to this function (otherwise
  ** the non-overloaded version would have been called instead of this one).
  */
  assert( nVal>=1 );

  if( nVal>6 ){
    sqlite3_result_error(pContext,
        "wrong number of arguments to function snippet()", -1);
    return;
  }
  if( fts3FunctionArg(pContext, "snippet", apVal[0], &pCsr) ) return;

  switch( nVal ){
    case 6: nToken = sqlite3_value_int(apVal[5]);
            /* no break */ deliberate_fall_through
    case 5: iCol = sqlite3_value_int(apVal[4]);
            /* no break */ deliberate_fall_through
    case 4: zEllipsis = (const char*)sqlite3_value_text(apVal[3]);
            /* no break */ deliberate_fall_through
    case 3: zEnd = (const char*)sqlite3_value_text(apVal[2]);
            /* no break */ deliberate_fall_through
    case 2: zStart = (const char*)sqlite3_value_text(apVal[1]);
  }
  if( !zEllipsis || !zEnd || !zStart ){
    sqlite3_result_error_nomem(pContext);
  }else if( nToken==0 ){
    sqlite3_result_text(pContext, "", -1, SQLITE_STATIC);
  }else if( SQLITE_OK==fts3CursorSeek(pContext, pCsr) ){
    sqlite3Fts3Snippet(pContext, pCsr, zStart, zEnd, zEllipsis, iCol, nToken);
  }
}

/*
** Implementation of the offsets() function for FTS3

sqlite3.c  view on Meta::CPAN

#ifndef SQLITE_DISABLE_FTS3_UNICODE
     || sqlite3Fts3HashInsert(&pHash->hash, "unicode61", 10, (void *)pUnicode)
#endif
#ifdef SQLITE_ENABLE_ICU
     || (pIcu && sqlite3Fts3HashInsert(&pHash->hash, "icu", 4, (void *)pIcu))
#endif
    ){
      rc = SQLITE_NOMEM;
    }
  }

#ifdef SQLITE_TEST
  if( rc==SQLITE_OK ){
    rc = sqlite3Fts3ExprInitTestInterface(db, &pHash->hash);
  }
#endif

  /* Create the virtual table wrapper around the hash-table and overload
  ** the four scalar functions. If this is successful, register the
  ** module with sqlite.
  */
  if( SQLITE_OK==rc
   && SQLITE_OK==(rc=sqlite3Fts3InitHashTable(db,&pHash->hash,"fts3_tokenizer"))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", 1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 1))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "matchinfo", 2))
   && SQLITE_OK==(rc = sqlite3_overload_function(db, "optimize", 1))
  ){
    pHash->nRef++;
    rc = sqlite3_create_module_v2(
        db, "fts3", &fts3Module, (void *)pHash, hashDestroy
    );
    if( rc==SQLITE_OK ){
      pHash->nRef++;
      rc = sqlite3_create_module_v2(
          db, "fts4", &fts3Module, (void *)pHash, hashDestroy
      );
    }
    if( rc==SQLITE_OK ){
      pHash->nRef++;
      rc = sqlite3Fts3InitTok(db, (void *)pHash, hashDestroy);
    }
    return rc;
  }


  /* An error has occurred. Delete the hash table and return the error code. */
  assert( rc!=SQLITE_OK );
  if( pHash ){
    sqlite3Fts3HashClear(&pHash->hash);
    sqlite3_free(pHash);
  }
  return rc;
}

/*
** Allocate an Fts3MultiSegReader for each token in the expression headed
** by pExpr.
**
** An Fts3SegReader object is a cursor that can seek or scan a range of
** entries within a single segment b-tree. An Fts3MultiSegReader uses multiple
** Fts3SegReader objects internally to provide an interface to seek or scan
** within the union of all segments of a b-tree. Hence the name.
**
** If the allocated Fts3MultiSegReader just seeks to a single entry in a
** segment b-tree (if the term is not a prefix or it is a prefix for which
** there exists prefix b-tree of the right length) then it may be traversed
** and merged incrementally. Otherwise, it has to be merged into an in-memory
** doclist and then traversed.
*/
static void fts3EvalAllocateReaders(
  Fts3Cursor *pCsr,               /* FTS cursor handle */
  Fts3Expr *pExpr,                /* Allocate readers for this expression */
  int *pnToken,                   /* OUT: Total number of tokens in phrase. */
  int *pnOr,                      /* OUT: Total number of OR nodes in expr. */
  int *pRc                        /* IN/OUT: Error code */
){
  if( pExpr && SQLITE_OK==*pRc ){
    if( pExpr->eType==FTSQUERY_PHRASE ){
      int i;
      int nToken = pExpr->pPhrase->nToken;
      *pnToken += nToken;
      for(i=0; i<nToken; i++){
        Fts3PhraseToken *pToken = &pExpr->pPhrase->aToken[i];
        int rc = fts3TermSegReaderCursor(pCsr,
            pToken->z, pToken->n, pToken->isPrefix, &pToken->pSegcsr
        );
        if( rc!=SQLITE_OK ){
          *pRc = rc;
          return;
        }
      }
      assert( pExpr->pPhrase->iDoclistToken==0 );
      pExpr->pPhrase->iDoclistToken = -1;
    }else{
      *pnOr += (pExpr->eType==FTSQUERY_OR);
      fts3EvalAllocateReaders(pCsr, pExpr->pLeft, pnToken, pnOr, pRc);
      fts3EvalAllocateReaders(pCsr, pExpr->pRight, pnToken, pnOr, pRc);
    }
  }
}

/*
** Arguments pList/nList contain the doclist for token iToken of phrase p.
** It is merged into the main doclist stored in p->doclist.aAll/nAll.
**
** This function assumes that pList points to a buffer allocated using
** sqlite3_malloc(). This function takes responsibility for eventually
** freeing the buffer.
**
** SQLITE_OK is returned if successful, or SQLITE_NOMEM if an error occurs.
*/
static int fts3EvalPhraseMergeToken(
  Fts3Table *pTab,                /* FTS Table pointer */
  Fts3Phrase *p,                  /* Phrase to merge pList/nList into */
  int iToken,                     /* Token pList/nList corresponds to */
  char *pList,                    /* Pointer to doclist */
  int nList                       /* Number of bytes in pList */
){
  int rc = SQLITE_OK;
  assert( iToken!=p->iDoclistToken );

  if( pList==0 ){
    sqlite3_free(p->doclist.aAll);
    p->doclist.aAll = 0;
    p->doclist.nAll = 0;
  }

  else if( p->iDoclistToken<0 ){
    p->doclist.aAll = pList;
    p->doclist.nAll = nList;
  }

sqlite3.c  view on Meta::CPAN

  if( *pRc==SQLITE_OK
   && pExpr->eType==FTSQUERY_NEAR
   && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR)
  ){
    Fts3Expr *p;
    sqlite3_int64 nTmp = 0;       /* Bytes of temp space */
    char *aTmp;                   /* Temp space for PoslistNearMerge() */

    /* Allocate temporary working space. */
    for(p=pExpr; p->pLeft; p=p->pLeft){
      assert( p->pRight->pPhrase->doclist.nList>0 );
      nTmp += p->pRight->pPhrase->doclist.nList;
    }
    nTmp += p->pPhrase->doclist.nList;
    aTmp = sqlite3_malloc64(nTmp*2 + FTS3_VARINT_MAX);
    if( !aTmp ){
      *pRc = SQLITE_NOMEM;
      res = 0;
    }else{
      char *aPoslist = p->pPhrase->doclist.pList;
      int nToken = p->pPhrase->nToken;

      for(p=p->pParent;res && p && p->eType==FTSQUERY_NEAR; p=p->pParent){
        Fts3Phrase *pPhrase = p->pRight->pPhrase;
        int nNear = p->nNear;
        res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase);
      }

      aPoslist = pExpr->pRight->pPhrase->doclist.pList;
      nToken = pExpr->pRight->pPhrase->nToken;
      for(p=pExpr->pLeft; p && res; p=p->pLeft){
        int nNear;
        Fts3Phrase *pPhrase;
        assert( p->pParent && p->pParent->pLeft==p );
        nNear = p->pParent->nNear;
        pPhrase = (
            p->eType==FTSQUERY_NEAR ? p->pRight->pPhrase : p->pPhrase
        );
        res = fts3EvalNearTrim(nNear, aTmp, &aPoslist, &nToken, pPhrase);
      }
    }

    sqlite3_free(aTmp);
  }

  return res;
}

/*
** This function is a helper function for sqlite3Fts3EvalTestDeferred().
** Assuming no error occurs or has occurred, It returns non-zero if the
** expression passed as the second argument matches the row that pCsr
** currently points to, or zero if it does not.
**
** If *pRc is not SQLITE_OK when this function is called, it is a no-op.
** If an error occurs during execution of this function, *pRc is set to
** the appropriate SQLite error code. In this case the returned value is
** undefined.
*/
static int fts3EvalTestExpr(
  Fts3Cursor *pCsr,               /* FTS cursor handle */
  Fts3Expr *pExpr,                /* Expr to test. May or may not be root. */
  int *pRc                        /* IN/OUT: Error code */
){
  int bHit = 1;                   /* Return value */
  if( *pRc==SQLITE_OK ){
    switch( pExpr->eType ){
      case FTSQUERY_NEAR:
      case FTSQUERY_AND:
        bHit = (
            fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc)
         && fts3EvalTestExpr(pCsr, pExpr->pRight, pRc)
         && fts3EvalNearTest(pExpr, pRc)
        );

        /* If the NEAR expression does not match any rows, zero the doclist for
        ** all phrases involved in the NEAR. This is because the snippet(),
        ** offsets() and matchinfo() functions are not supposed to recognize
        ** any instances of phrases that are part of unmatched NEAR queries.
        ** For example if this expression:
        **
        **    ... MATCH 'a OR (b NEAR c)'
        **
        ** is matched against a row containing:
        **
        **        'a b d e'
        **
        ** then any snippet() should ony highlight the "a" term, not the "b"
        ** (as "b" is part of a non-matching NEAR clause).
        */
        if( bHit==0
         && pExpr->eType==FTSQUERY_NEAR
         && (pExpr->pParent==0 || pExpr->pParent->eType!=FTSQUERY_NEAR)
        ){
          Fts3Expr *p;
          for(p=pExpr; p->pPhrase==0; p=p->pLeft){
            if( p->pRight->iDocid==pCsr->iPrevId ){
              fts3EvalInvalidatePoslist(p->pRight->pPhrase);
            }
          }
          if( p->iDocid==pCsr->iPrevId ){
            fts3EvalInvalidatePoslist(p->pPhrase);
          }
        }

        break;

      case FTSQUERY_OR: {
        int bHit1 = fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc);
        int bHit2 = fts3EvalTestExpr(pCsr, pExpr->pRight, pRc);
        bHit = bHit1 || bHit2;
        break;
      }

      case FTSQUERY_NOT:
        bHit = (
            fts3EvalTestExpr(pCsr, pExpr->pLeft, pRc)
         && !fts3EvalTestExpr(pCsr, pExpr->pRight, pRc)
        );
        break;

      default: {
#ifndef SQLITE_DISABLE_FTS4_DEFERRED
        if( pCsr->pDeferred && (pExpr->bDeferred || (
            pExpr->iDocid==pCsr->iPrevId && pExpr->pPhrase->doclist.pList
        ))){
          Fts3Phrase *pPhrase = pExpr->pPhrase;
          if( pExpr->bDeferred ){
            fts3EvalInvalidatePoslist(pPhrase);
          }
          *pRc = fts3EvalDeferredPhrase(pCsr, pPhrase);
          bHit = (pPhrase->doclist.pList!=0);
          pExpr->iDocid = pCsr->iPrevId;
        }else
#endif
        {
          bHit = (
              pExpr->bEof==0 && pExpr->iDocid==pCsr->iPrevId
           && pExpr->pPhrase->doclist.nList>0
          );
        }
        break;
      }
    }
  }
  return bHit;
}

/*
** This function is called as the second part of each xNext operation when
** iterating through the results of a full-text query. At this point the
** cursor points to a row that matches the query expression, with the
** following caveats:
**
**   * Up until this point, "NEAR" operators in the expression have been
**     treated as "AND".
**
**   * Deferred tokens have not yet been considered.
**
** If *pRc is not SQLITE_OK when this function is called, it immediately
** returns 0. Otherwise, it tests whether or not after considering NEAR
** operators and deferred tokens the current row is still a match for the
** expression. It returns 1 if both of the following are true:
**
**   1. *pRc is SQLITE_OK when this function returns, and
**
**   2. After scanning the current FTS table row for the deferred tokens,
**      it is determined that the row does *not* match the query.
**
** Or, if no error occurs and it seems the current row does match the FTS
** query, return 0.
*/
SQLITE_PRIVATE int sqlite3Fts3EvalTestDeferred(Fts3Cursor *pCsr, int *pRc){
  int rc = *pRc;
  int bMiss = 0;
  if( rc==SQLITE_OK ){

    /* If there are one or more deferred tokens, load the current row into
    ** memory and scan it to determine the position list for each deferred
    ** token. Then, see if this row is really a match, considering deferred
    ** tokens and NEAR operators (neither of which were taken into account
    ** earlier, by fts3EvalNextRow()).
    */
    if( pCsr->pDeferred ){
      rc = fts3CursorSeek(0, pCsr);
      if( rc==SQLITE_OK ){
        rc = sqlite3Fts3CacheDeferredDoclists(pCsr);
      }
    }
    bMiss = (0==fts3EvalTestExpr(pCsr, pCsr->pExpr, &rc));

    /* Free the position-lists accumulated for each deferred token above. */
    sqlite3Fts3FreeDeferredDoclists(pCsr);
    *pRc = rc;
  }
  return (rc==SQLITE_OK && bMiss);
}

/*
** Advance to the next document that matches the FTS expression in
** Fts3Cursor.pExpr.
*/
static int fts3EvalNext(Fts3Cursor *pCsr){
  int rc = SQLITE_OK;             /* Return Code */
  Fts3Expr *pExpr = pCsr->pExpr;
  assert( pCsr->isEof==0 );
  if( pExpr==0 ){
    pCsr->isEof = 1;
  }else{
    do {
      if( pCsr->isRequireSeek==0 ){
        sqlite3_reset(pCsr->pStmt);
      }
      assert( sqlite3_data_count(pCsr->pStmt)==0 );
      fts3EvalNextRow(pCsr, pExpr, &rc);
      pCsr->isEof = pExpr->bEof;
      pCsr->isRequireSeek = 1;
      pCsr->isMatchinfoNeeded = 1;
      pCsr->iPrevId = pExpr->iDocid;
    }while( pCsr->isEof==0 && sqlite3Fts3EvalTestDeferred(pCsr, &rc) );
  }

  /* Check if the cursor is past the end of the docid range specified
  ** by Fts3Cursor.iMinDocid/iMaxDocid. If so, set the EOF flag.  */
  if( rc==SQLITE_OK && (
        (pCsr->bDesc==0 && pCsr->iPrevId>pCsr->iMaxDocid)
     || (pCsr->bDesc!=0 && pCsr->iPrevId<pCsr->iMinDocid)
  )){
    pCsr->isEof = 1;
  }

  return rc;
}

/*
** Restart iteration for expression pExpr so that the next call to
** fts3EvalNext() visits the first row. Do not allow incremental
** loading or merging of phrase doclists for this iteration.
**
** If *pRc is other than SQLITE_OK when this function is called, it is
** a no-op. If an error occurs within this function, *pRc is set to an
** SQLite error code before returning.
*/
static void fts3EvalRestart(
  Fts3Cursor *pCsr,
  Fts3Expr *pExpr,
  int *pRc
){
  if( pExpr && *pRc==SQLITE_OK ){
    Fts3Phrase *pPhrase = pExpr->pPhrase;

    if( pPhrase ){
      fts3EvalInvalidatePoslist(pPhrase);
      if( pPhrase->bIncr ){
        int i;
        for(i=0; i<pPhrase->nToken; i++){
          Fts3PhraseToken *pToken = &pPhrase->aToken[i];
          assert( pToken->pDeferred==0 );
          if( pToken->pSegcsr ){
            sqlite3Fts3MsrIncrRestart(pToken->pSegcsr);
          }
        }
        *pRc = fts3EvalPhraseStart(pCsr, 0, pPhrase);
      }
      pPhrase->doclist.pNextDocid = 0;
      pPhrase->doclist.iDocid = 0;
      pPhrase->pOrPoslist = 0;
    }

    pExpr->iDocid = 0;
    pExpr->bEof = 0;
    pExpr->bStart = 0;

    fts3EvalRestart(pCsr, pExpr->pLeft, pRc);
    fts3EvalRestart(pCsr, pExpr->pRight, pRc);
  }
}

/*
** Expression node pExpr is an MSR phrase. This function restarts pExpr
** so that it is a regular phrase query, not an MSR. SQLITE_OK is returned
** if successful, or an SQLite error code otherwise.
*/
SQLITE_PRIVATE int sqlite3Fts3MsrCancel(Fts3Cursor *pCsr, Fts3Expr *pExpr){
  int rc = SQLITE_OK;
  if( pExpr->bEof==0 ){
    i64 iDocid = pExpr->iDocid;
    fts3EvalRestart(pCsr, pExpr, &rc);
    while( rc==SQLITE_OK && pExpr->iDocid!=iDocid ){
      fts3EvalNextRow(pCsr, pExpr, &rc);
      if( pExpr->bEof ) rc = FTS_CORRUPT_VTAB;
    }
  }
  return rc;
}

/*
** After allocating the Fts3Expr.aMI[] array for each phrase in the
** expression rooted at pExpr, the cursor iterates through all rows matched
** by pExpr, calling this function for each row. This function increments
** the values in Fts3Expr.aMI[] according to the position-list currently
** found in Fts3Expr.pPhrase->doclist.pList for each of the phrase
** expression nodes.
*/
static void fts3EvalUpdateCounts(Fts3Expr *pExpr, int nCol){
  if( pExpr ){
    Fts3Phrase *pPhrase = pExpr->pPhrase;
    if( pPhrase && pPhrase->doclist.pList ){
      int iCol = 0;
      char *p = pPhrase->doclist.pList;

      do{
        u8 c = 0;
        int iCnt = 0;
        while( 0xFE & (*p | c) ){
          if( (c&0x80)==0 ) iCnt++;
          c = *p++ & 0x80;
        }

        /* aMI[iCol*3 + 1] = Number of occurrences
        ** aMI[iCol*3 + 2] = Number of rows containing at least one instance
        */
        pExpr->aMI[iCol*3 + 1] += iCnt;
        pExpr->aMI[iCol*3 + 2] += (iCnt>0);
        if( *p==0x00 ) break;
        p++;
        p += fts3GetVarint32(p, &iCol);
      }while( iCol<nCol );
    }

    fts3EvalUpdateCounts(pExpr->pLeft, nCol);
    fts3EvalUpdateCounts(pExpr->pRight, nCol);
  }
}

/*
** This is an sqlite3Fts3ExprIterate() callback. If the Fts3Expr.aMI[] array
** has not yet been allocated, allocate and zero it. Otherwise, just zero
** it.
*/
static int fts3AllocateMSI(Fts3Expr *pExpr, int iPhrase, void *pCtx){
  Fts3Table *pTab = (Fts3Table*)pCtx;
  UNUSED_PARAMETER(iPhrase);
  if( pExpr->aMI==0 ){
    pExpr->aMI = (u32 *)sqlite3_malloc64(pTab->nColumn * 3 * sizeof(u32));
    if( pExpr->aMI==0 ) return SQLITE_NOMEM;
  }
  memset(pExpr->aMI, 0, pTab->nColumn * 3 * sizeof(u32));
  return SQLITE_OK;
}

/*
** Expression pExpr must be of type FTSQUERY_PHRASE.
**
** If it is not already allocated and populated, this function allocates and
** populates the Fts3Expr.aMI[] array for expression pExpr. If pExpr is part
** of a NEAR expression, then it also allocates and populates the same array
** for all other phrases that are part of the NEAR expression.
**

sqlite3.c  view on Meta::CPAN


      if( rc==SQLITE_OK && pCsr->isEof==0 ){
        fts3EvalUpdateCounts(pRoot, pTab->nColumn);
      }
    }

    pCsr->isEof = 0;
    pCsr->iPrevId = iPrevId;

    if( bEof ){
      pRoot->bEof = bEof;
    }else{
      /* Caution: pRoot may iterate through docids in ascending or descending
      ** order. For this reason, even though it seems more defensive, the
      ** do loop can not be written:
      **
      **   do {...} while( pRoot->iDocid<iDocid && rc==SQLITE_OK );
      */
      fts3EvalRestart(pCsr, pRoot, &rc);
      do {
        fts3EvalNextRow(pCsr, pRoot, &rc);
        assert_fts3_nc( pRoot->bEof==0 );
        if( pRoot->bEof ) rc = FTS_CORRUPT_VTAB;
      }while( pRoot->iDocid!=iDocid && rc==SQLITE_OK );
    }
  }
  return rc;
}

/*
** This function is used by the matchinfo() module to query a phrase
** expression node for the following information:
**
**   1. The total number of occurrences of the phrase in each column of
**      the FTS table (considering all rows), and
**
**   2. For each column, the number of rows in the table for which the
**      column contains at least one instance of the phrase.
**
** If no error occurs, SQLITE_OK is returned and the values for each column
** written into the array aiOut as follows:
**
**   aiOut[iCol*3 + 1] = Number of occurrences
**   aiOut[iCol*3 + 2] = Number of rows containing at least one instance
**
** Caveats:
**
**   * If a phrase consists entirely of deferred tokens, then all output
**     values are set to the number of documents in the table. In other
**     words we assume that very common tokens occur exactly once in each
**     column of each row of the table.
**
**   * If a phrase contains some deferred tokens (and some non-deferred
**     tokens), count the potential occurrence identified by considering
**     the non-deferred tokens instead of actual phrase occurrences.
**
**   * If the phrase is part of a NEAR expression, then only phrase instances
**     that meet the NEAR constraint are included in the counts.
*/
SQLITE_PRIVATE int sqlite3Fts3EvalPhraseStats(
  Fts3Cursor *pCsr,               /* FTS cursor handle */
  Fts3Expr *pExpr,                /* Phrase expression */
  u32 *aiOut                      /* Array to write results into (see above) */
){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  int rc = SQLITE_OK;
  int iCol;

  if( pExpr->bDeferred && pExpr->pParent->eType!=FTSQUERY_NEAR ){
    assert( pCsr->nDoc>0 );
    for(iCol=0; iCol<pTab->nColumn; iCol++){
      aiOut[iCol*3 + 1] = (u32)pCsr->nDoc;
      aiOut[iCol*3 + 2] = (u32)pCsr->nDoc;
    }
  }else{
    rc = fts3EvalGatherStats(pCsr, pExpr);
    if( rc==SQLITE_OK ){
      assert( pExpr->aMI );
      for(iCol=0; iCol<pTab->nColumn; iCol++){
        aiOut[iCol*3 + 1] = pExpr->aMI[iCol*3 + 1];
        aiOut[iCol*3 + 2] = pExpr->aMI[iCol*3 + 2];
      }
    }
  }

  return rc;
}

/*
** The expression pExpr passed as the second argument to this function
** must be of type FTSQUERY_PHRASE.
**
** The returned value is either NULL or a pointer to a buffer containing
** a position-list indicating the occurrences of the phrase in column iCol
** of the current row.
**
** More specifically, the returned buffer contains 1 varint for each
** occurrence of the phrase in the column, stored using the normal (delta+2)
** compression and is terminated by either an 0x01 or 0x00 byte. For example,
** if the requested column contains "a b X c d X X" and the position-list
** for 'X' is requested, the buffer returned may contain:
**
**     0x04 0x05 0x03 0x01   or   0x04 0x05 0x03 0x00
**
** This function works regardless of whether or not the phrase is deferred,
** incremental, or neither.
*/
SQLITE_PRIVATE int sqlite3Fts3EvalPhrasePoslist(
  Fts3Cursor *pCsr,               /* FTS3 cursor object */
  Fts3Expr *pExpr,                /* Phrase to return doclist for */
  int iCol,                       /* Column to return position list for */
  char **ppOut                    /* OUT: Pointer to position list */
){
  Fts3Phrase *pPhrase = pExpr->pPhrase;
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  char *pIter;
  int iThis;
  sqlite3_int64 iDocid;

  /* If this phrase is applies specifically to some column other than
  ** column iCol, return a NULL pointer.  */
  *ppOut = 0;
  assert( iCol>=0 && iCol<pTab->nColumn );
  if( (pPhrase->iColumn<pTab->nColumn && pPhrase->iColumn!=iCol) ){
    return SQLITE_OK;
  }

  iDocid = pExpr->iDocid;
  pIter = pPhrase->doclist.pList;
  if( iDocid!=pCsr->iPrevId || pExpr->bEof ){
    int rc = SQLITE_OK;
    int bDescDoclist = pTab->bDescIdx;      /* For DOCID_CMP macro */
    int bOr = 0;
    u8 bTreeEof = 0;
    Fts3Expr *p;                  /* Used to iterate from pExpr to root */
    Fts3Expr *pNear;              /* Most senior NEAR ancestor (or pExpr) */
    Fts3Expr *pRun;               /* Closest non-deferred ancestor of pNear */
    int bMatch;

    /* Check if this phrase descends from an OR expression node. If not,
    ** return NULL. Otherwise, the entry that corresponds to docid
    ** pCsr->iPrevId may lie earlier in the doclist buffer. Or, if the
    ** tree that the node is part of has been marked as EOF, but the node
    ** itself is not EOF, then it may point to an earlier entry. */
    pNear = pExpr;
    for(p=pExpr->pParent; p; p=p->pParent){
      if( p->eType==FTSQUERY_OR ) bOr = 1;
      if( p->eType==FTSQUERY_NEAR ) pNear = p;
      if( p->bEof ) bTreeEof = 1;
    }
    if( bOr==0 ) return SQLITE_OK;
    pRun = pNear;
    while( pRun->bDeferred ){
      assert( pRun->pParent );
      pRun = pRun->pParent;
    }

    /* This is the descendent of an OR node. In this case we cannot use
    ** an incremental phrase. Load the entire doclist for the phrase
    ** into memory in this case.  */
    if( pPhrase->bIncr ){
      int bEofSave = pRun->bEof;
      fts3EvalRestart(pCsr, pRun, &rc);
      while( rc==SQLITE_OK && !pRun->bEof ){
        fts3EvalNextRow(pCsr, pRun, &rc);
        if( bEofSave==0 && pRun->iDocid==iDocid ) break;
      }
      assert( rc!=SQLITE_OK || pPhrase->bIncr==0 );
      if( rc==SQLITE_OK && pRun->bEof!=bEofSave ){

sqlite3.c  view on Meta::CPAN



/*
** Return SQLITE_CORRUPT_VTAB.
*/
#ifdef SQLITE_DEBUG
SQLITE_PRIVATE int sqlite3Fts3Corrupt(){
  return SQLITE_CORRUPT_VTAB;
}
#endif

#if !defined(SQLITE_CORE)
/*
** Initialize API pointer table, if required.
*/
#ifdef _WIN32
__declspec(dllexport)
#endif
SQLITE_API int sqlite3_fts3_init(
  sqlite3 *db,
  char **pzErrMsg,
  const sqlite3_api_routines *pApi
){
  SQLITE_EXTENSION_INIT2(pApi)
  return sqlite3Fts3Init(db);
}
#endif

#endif

/************** End of fts3.c ************************************************/
/************** Begin file fts3_aux.c ****************************************/
/*
** 2011 Jan 27
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
*/
/* #include "fts3Int.h" */
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)

/* #include <string.h> */
/* #include <assert.h> */

typedef struct Fts3auxTable Fts3auxTable;
typedef struct Fts3auxCursor Fts3auxCursor;

struct Fts3auxTable {
  sqlite3_vtab base;              /* Base class used by SQLite core */
  Fts3Table *pFts3Tab;
};

struct Fts3auxCursor {
  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
  Fts3MultiSegReader csr;        /* Must be right after "base" */
  Fts3SegFilter filter;
  char *zStop;
  int nStop;                      /* Byte-length of string zStop */
  int iLangid;                    /* Language id to query */
  int isEof;                      /* True if cursor is at EOF */
  sqlite3_int64 iRowid;           /* Current rowid */

  int iCol;                       /* Current value of 'col' column */
  int nStat;                      /* Size of aStat[] array */
  struct Fts3auxColstats {
    sqlite3_int64 nDoc;           /* 'documents' values for current csr row */
    sqlite3_int64 nOcc;           /* 'occurrences' values for current csr row */
  } *aStat;
};

/*
** Schema of the terms table.
*/
#define FTS3_AUX_SCHEMA \
  "CREATE TABLE x(term, col, documents, occurrences, languageid HIDDEN)"

/*
** This function does all the work for both the xConnect and xCreate methods.
** These tables have no persistent representation of their own, so xConnect
** and xCreate are identical operations.
*/
static int fts3auxConnectMethod(
  sqlite3 *db,                    /* Database connection */
  void *pUnused,                  /* Unused */
  int argc,                       /* Number of elements in argv array */
  const char * const *argv,       /* xCreate/xConnect argument array */
  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
){
  char const *zDb;                /* Name of database (e.g. "main") */
  char const *zFts3;              /* Name of fts3 table */
  int nDb;                        /* Result of strlen(zDb) */
  int nFts3;                      /* Result of strlen(zFts3) */
  sqlite3_int64 nByte;            /* Bytes of space to allocate here */
  int rc;                         /* value returned by declare_vtab() */
  Fts3auxTable *p;                /* Virtual table object to return */

  UNUSED_PARAMETER(pUnused);

  /* The user should invoke this in one of two forms:
  **
  **     CREATE VIRTUAL TABLE xxx USING fts4aux(fts4-table);
  **     CREATE VIRTUAL TABLE xxx USING fts4aux(fts4-table-db, fts4-table);
  */
  if( argc!=4 && argc!=5 ) goto bad_args;

  zDb = argv[1];
  nDb = (int)strlen(zDb);
  if( argc==5 ){
    if( nDb==4 && 0==sqlite3_strnicmp("temp", zDb, 4) ){
      zDb = argv[3];
      nDb = (int)strlen(zDb);
      zFts3 = argv[4];
    }else{
      goto bad_args;
    }
  }else{
    zFts3 = argv[3];
  }
  nFts3 = (int)strlen(zFts3);

sqlite3.c  view on Meta::CPAN

  int iLangid = -1;
  int iNext = 1;                  /* Next free argvIndex value */

  UNUSED_PARAMETER(pVTab);

  /* This vtab delivers always results in "ORDER BY term ASC" order. */
  if( pInfo->nOrderBy==1
   && pInfo->aOrderBy[0].iColumn==0
   && pInfo->aOrderBy[0].desc==0
  ){
    pInfo->orderByConsumed = 1;
  }

  /* Search for equality and range constraints on the "term" column.
  ** And equality constraints on the hidden "languageid" column. */
  for(i=0; i<pInfo->nConstraint; i++){
    if( pInfo->aConstraint[i].usable ){
      int op = pInfo->aConstraint[i].op;
      int iCol = pInfo->aConstraint[i].iColumn;

      if( iCol==0 ){
        if( op==SQLITE_INDEX_CONSTRAINT_EQ ) iEq = i;
        if( op==SQLITE_INDEX_CONSTRAINT_LT ) iLe = i;
        if( op==SQLITE_INDEX_CONSTRAINT_LE ) iLe = i;
        if( op==SQLITE_INDEX_CONSTRAINT_GT ) iGe = i;
        if( op==SQLITE_INDEX_CONSTRAINT_GE ) iGe = i;
      }
      if( iCol==4 ){
        if( op==SQLITE_INDEX_CONSTRAINT_EQ ) iLangid = i;
      }
    }
  }

  if( iEq>=0 ){
    pInfo->idxNum = FTS4AUX_EQ_CONSTRAINT;
    pInfo->aConstraintUsage[iEq].argvIndex = iNext++;
    pInfo->estimatedCost = 5;
  }else{
    pInfo->idxNum = 0;
    pInfo->estimatedCost = 20000;
    if( iGe>=0 ){
      pInfo->idxNum += FTS4AUX_GE_CONSTRAINT;
      pInfo->aConstraintUsage[iGe].argvIndex = iNext++;
      pInfo->estimatedCost /= 2;
    }
    if( iLe>=0 ){
      pInfo->idxNum += FTS4AUX_LE_CONSTRAINT;
      pInfo->aConstraintUsage[iLe].argvIndex = iNext++;
      pInfo->estimatedCost /= 2;
    }
  }
  if( iLangid>=0 ){
    pInfo->aConstraintUsage[iLangid].argvIndex = iNext++;
    pInfo->estimatedCost--;
  }

  return SQLITE_OK;
}

/*
** xOpen - Open a cursor.
*/
static int fts3auxOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
  Fts3auxCursor *pCsr;            /* Pointer to cursor object to return */

  UNUSED_PARAMETER(pVTab);

  pCsr = (Fts3auxCursor *)sqlite3_malloc(sizeof(Fts3auxCursor));
  if( !pCsr ) return SQLITE_NOMEM;
  memset(pCsr, 0, sizeof(Fts3auxCursor));

  *ppCsr = (sqlite3_vtab_cursor *)pCsr;
  return SQLITE_OK;
}

/*
** xClose - Close a cursor.
*/
static int fts3auxCloseMethod(sqlite3_vtab_cursor *pCursor){
  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;

  sqlite3Fts3SegmentsClose(pFts3);
  sqlite3Fts3SegReaderFinish(&pCsr->csr);
  sqlite3_free((void *)pCsr->filter.zTerm);
  sqlite3_free(pCsr->zStop);
  sqlite3_free(pCsr->aStat);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

static int fts3auxGrowStatArray(Fts3auxCursor *pCsr, int nSize){
  if( nSize>pCsr->nStat ){
    struct Fts3auxColstats *aNew;
    aNew = (struct Fts3auxColstats *)sqlite3_realloc64(pCsr->aStat,
        sizeof(struct Fts3auxColstats) * nSize
    );
    if( aNew==0 ) return SQLITE_NOMEM;
    memset(&aNew[pCsr->nStat], 0,
        sizeof(struct Fts3auxColstats) * (nSize - pCsr->nStat)
    );
    pCsr->aStat = aNew;
    pCsr->nStat = nSize;
  }
  return SQLITE_OK;
}

/*
** xNext - Advance the cursor to the next row, if any.
*/
static int fts3auxNextMethod(sqlite3_vtab_cursor *pCursor){
  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
  int rc;

  /* Increment our pretend rowid value. */
  pCsr->iRowid++;

  for(pCsr->iCol++; pCsr->iCol<pCsr->nStat; pCsr->iCol++){
    if( pCsr->aStat[pCsr->iCol].nDoc>0 ) return SQLITE_OK;
  }

  rc = sqlite3Fts3SegReaderStep(pFts3, &pCsr->csr);
  if( rc==SQLITE_ROW ){
    int i = 0;
    int nDoclist = pCsr->csr.nDoclist;
    char *aDoclist = pCsr->csr.aDoclist;
    int iCol;

    int eState = 0;

    if( pCsr->zStop ){
      int n = (pCsr->nStop<pCsr->csr.nTerm) ? pCsr->nStop : pCsr->csr.nTerm;
      int mc = memcmp(pCsr->zStop, pCsr->csr.zTerm, n);
      if( mc<0 || (mc==0 && pCsr->csr.nTerm>pCsr->nStop) ){
        pCsr->isEof = 1;
        return SQLITE_OK;
      }
    }

    if( fts3auxGrowStatArray(pCsr, 2) ) return SQLITE_NOMEM;
    memset(pCsr->aStat, 0, sizeof(struct Fts3auxColstats) * pCsr->nStat);
    iCol = 0;
    rc = SQLITE_OK;

    while( i<nDoclist ){
      sqlite3_int64 v = 0;

      i += sqlite3Fts3GetVarint(&aDoclist[i], &v);
      switch( eState ){
        /* State 0. In this state the integer just read was a docid. */
        case 0:
          pCsr->aStat[0].nDoc++;
          eState = 1;
          iCol = 0;
          break;

        /* State 1. In this state we are expecting either a 1, indicating
        ** that the following integer will be a column number, or the
        ** start of a position list for column 0.
        **
        ** The only difference between state 1 and state 2 is that if the
        ** integer encountered in state 1 is not 0 or 1, then we need to
        ** increment the column 0 "nDoc" count for this term.
        */
        case 1:
          assert( iCol==0 );
          if( v>1 ){
            pCsr->aStat[1].nDoc++;
          }
          eState = 2;
          /* fall through */

        case 2:
          if( v==0 ){       /* 0x00. Next integer will be a docid. */
            eState = 0;
          }else if( v==1 ){ /* 0x01. Next integer will be a column number. */
            eState = 3;
          }else{            /* 2 or greater. A position. */
            pCsr->aStat[iCol+1].nOcc++;
            pCsr->aStat[0].nOcc++;
          }
          break;

        /* State 3. The integer just read is a column number. */
        default: assert( eState==3 );
          iCol = (int)v;
          if( iCol<1 ){
            rc = SQLITE_CORRUPT_VTAB;
            break;
          }
          if( fts3auxGrowStatArray(pCsr, iCol+2) ) return SQLITE_NOMEM;
          pCsr->aStat[iCol+1].nDoc++;
          eState = 2;
          break;
      }
    }

    pCsr->iCol = 0;
  }else{
    pCsr->isEof = 1;
  }
  return rc;
}

/*
** xFilter - Initialize a cursor to point at the start of its data.
*/
static int fts3auxFilterMethod(
  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
  int idxNum,                     /* Strategy index */
  const char *idxStr,             /* Unused */
  int nVal,                       /* Number of elements in apVal */
  sqlite3_value **apVal           /* Arguments for the indexing scheme */
){
  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
  int rc;
  int isScan = 0;
  int iLangVal = 0;               /* Language id to query */

  int iEq = -1;                   /* Index of term=? value in apVal */
  int iGe = -1;                   /* Index of term>=? value in apVal */
  int iLe = -1;                   /* Index of term<=? value in apVal */
  int iLangid = -1;               /* Index of languageid=? value in apVal */
  int iNext = 0;

  UNUSED_PARAMETER(nVal);
  UNUSED_PARAMETER(idxStr);

  assert( idxStr==0 );
  assert( idxNum==FTS4AUX_EQ_CONSTRAINT || idxNum==0
       || idxNum==FTS4AUX_LE_CONSTRAINT || idxNum==FTS4AUX_GE_CONSTRAINT
       || idxNum==(FTS4AUX_LE_CONSTRAINT|FTS4AUX_GE_CONSTRAINT)
  );

  if( idxNum==FTS4AUX_EQ_CONSTRAINT ){
    iEq = iNext++;
  }else{
    isScan = 1;
    if( idxNum & FTS4AUX_GE_CONSTRAINT ){
      iGe = iNext++;
    }
    if( idxNum & FTS4AUX_LE_CONSTRAINT ){
      iLe = iNext++;
    }
  }
  if( iNext<nVal ){
    iLangid = iNext++;
  }

  /* In case this cursor is being reused, close and zero it. */
  testcase(pCsr->filter.zTerm);
  sqlite3Fts3SegReaderFinish(&pCsr->csr);
  sqlite3_free((void *)pCsr->filter.zTerm);
  sqlite3_free(pCsr->aStat);
  sqlite3_free(pCsr->zStop);
  memset(&pCsr->csr, 0, ((u8*)&pCsr[1]) - (u8*)&pCsr->csr);

  pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
  if( isScan ) pCsr->filter.flags |= FTS3_SEGMENT_SCAN;

  if( iEq>=0 || iGe>=0 ){
    const unsigned char *zStr = sqlite3_value_text(apVal[0]);
    assert( (iEq==0 && iGe==-1) || (iEq==-1 && iGe==0) );
    if( zStr ){
      pCsr->filter.zTerm = sqlite3_mprintf("%s", zStr);
      if( pCsr->filter.zTerm==0 ) return SQLITE_NOMEM;
      pCsr->filter.nTerm = (int)strlen(pCsr->filter.zTerm);
    }
  }

  if( iLe>=0 ){
    pCsr->zStop = sqlite3_mprintf("%s", sqlite3_value_text(apVal[iLe]));
    if( pCsr->zStop==0 ) return SQLITE_NOMEM;
    pCsr->nStop = (int)strlen(pCsr->zStop);
  }

  if( iLangid>=0 ){
    iLangVal = sqlite3_value_int(apVal[iLangid]);

    /* If the user specified a negative value for the languageid, use zero
    ** instead. This works, as the "languageid=?" constraint will also
    ** be tested by the VDBE layer. The test will always be false (since
    ** this module will not return a row with a negative languageid), and
    ** so the overall query will return zero rows.  */
    if( iLangVal<0 ) iLangVal = 0;
  }
  pCsr->iLangid = iLangVal;

  rc = sqlite3Fts3SegReaderCursor(pFts3, iLangVal, 0, FTS3_SEGCURSOR_ALL,
      pCsr->filter.zTerm, pCsr->filter.nTerm, 0, isScan, &pCsr->csr
  );
  if( rc==SQLITE_OK ){
    rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter);
  }

  if( rc==SQLITE_OK ) rc = fts3auxNextMethod(pCursor);
  return rc;
}

/*
** xEof - Return true if the cursor is at EOF, or false otherwise.
*/
static int fts3auxEofMethod(sqlite3_vtab_cursor *pCursor){
  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
  return pCsr->isEof;
}

/*
** xColumn - Return a column value.
*/
static int fts3auxColumnMethod(
  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
  int iCol                        /* Index of column to read value from */
){
  Fts3auxCursor *p = (Fts3auxCursor *)pCursor;

  assert( p->isEof==0 );
  switch( iCol ){
    case 0: /* term */
      sqlite3_result_text(pCtx, p->csr.zTerm, p->csr.nTerm, SQLITE_TRANSIENT);
      break;

    case 1: /* col */
      if( p->iCol ){
        sqlite3_result_int(pCtx, p->iCol-1);
      }else{
        sqlite3_result_text(pCtx, "*", -1, SQLITE_STATIC);
      }
      break;

    case 2: /* documents */
      sqlite3_result_int64(pCtx, p->aStat[p->iCol].nDoc);
      break;

    case 3: /* occurrences */
      sqlite3_result_int64(pCtx, p->aStat[p->iCol].nOcc);
      break;

    default: /* languageid */
      assert( iCol==4 );
      sqlite3_result_int(pCtx, p->iLangid);
      break;
  }

  return SQLITE_OK;
}

/*
** xRowid - Return the current rowid for the cursor.
*/
static int fts3auxRowidMethod(
  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
  sqlite_int64 *pRowid            /* OUT: Rowid value */
){
  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
  *pRowid = pCsr->iRowid;
  return SQLITE_OK;
}

/*
** Register the fts3aux module with database connection db. Return SQLITE_OK
** if successful or an error code if sqlite3_create_module() fails.
*/
SQLITE_PRIVATE int sqlite3Fts3InitAux(sqlite3 *db){
  static const sqlite3_module fts3aux_module = {
     0,                           /* iVersion      */
     fts3auxConnectMethod,        /* xCreate       */
     fts3auxConnectMethod,        /* xConnect      */
     fts3auxBestIndexMethod,      /* xBestIndex    */
     fts3auxDisconnectMethod,     /* xDisconnect   */
     fts3auxDisconnectMethod,     /* xDestroy      */
     fts3auxOpenMethod,           /* xOpen         */
     fts3auxCloseMethod,          /* xClose        */
     fts3auxFilterMethod,         /* xFilter       */
     fts3auxNextMethod,           /* xNext         */
     fts3auxEofMethod,            /* xEof          */
     fts3auxColumnMethod,         /* xColumn       */
     fts3auxRowidMethod,          /* xRowid        */
     0,                           /* xUpdate       */
     0,                           /* xBegin        */
     0,                           /* xSync         */
     0,                           /* xCommit       */
     0,                           /* xRollback     */
     0,                           /* xFindFunction */
     0,                           /* xRename       */
     0,                           /* xSavepoint    */
     0,                           /* xRelease      */
     0,                           /* xRollbackTo   */
     0,                           /* xShadowName   */
     0                            /* xIntegrity    */
  };
  int rc;                         /* Return code */

  rc = sqlite3_create_module(db, "fts4aux", &fts3aux_module, 0);
  return rc;
}

#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */

/************** End of fts3_aux.c ********************************************/
/************** Begin file fts3_expr.c ***************************************/
/*
** 2008 Nov 28
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************

sqlite3.c  view on Meta::CPAN

/*
** Default span for NEAR operators.
*/
#define SQLITE_FTS3_DEFAULT_NEAR_PARAM 10

/* #include <string.h> */
/* #include <assert.h> */

/*
** isNot:
**   This variable is used by function getNextNode(). When getNextNode() is
**   called, it sets ParseContext.isNot to true if the 'next node' is a
**   FTSQUERY_PHRASE with a unary "-" attached to it. i.e. "mysql" in the
**   FTS3 query "sqlite -mysql". Otherwise, ParseContext.isNot is set to
**   zero.
*/
typedef struct ParseContext ParseContext;
struct ParseContext {
  sqlite3_tokenizer *pTokenizer;      /* Tokenizer module */
  int iLangid;                        /* Language id used with tokenizer */
  const char **azCol;                 /* Array of column names for fts3 table */
  int bFts4;                          /* True to allow FTS4-only syntax */
  int nCol;                           /* Number of entries in azCol[] */
  int iDefaultCol;                    /* Default column to query */
  int isNot;                          /* True if getNextNode() sees a unary - */
  sqlite3_context *pCtx;              /* Write error message here */
  int nNest;                          /* Number of nested brackets */
};

/*
** This function is equivalent to the standard isspace() function.
**
** The standard isspace() can be awkward to use safely, because although it
** is defined to accept an argument of type int, its behavior when passed
** an integer that falls outside of the range of the unsigned char type
** is undefined (and sometimes, "undefined" means segfault). This wrapper
** is defined to accept an argument of type char, and always returns 0 for
** any values that fall outside of the range of the unsigned char type (i.e.
** negative values).
*/
static int fts3isspace(char c){
  return c==' ' || c=='\t' || c=='\n' || c=='\r' || c=='\v' || c=='\f';
}

/*
** Allocate nByte bytes of memory using sqlite3_malloc(). If successful,
** zero the memory before returning a pointer to it. If unsuccessful,
** return NULL.
*/
SQLITE_PRIVATE void *sqlite3Fts3MallocZero(sqlite3_int64 nByte){
  void *pRet = sqlite3_malloc64(nByte);
  if( pRet ) memset(pRet, 0, nByte);
  return pRet;
}

SQLITE_PRIVATE int sqlite3Fts3OpenTokenizer(
  sqlite3_tokenizer *pTokenizer,
  int iLangid,
  const char *z,
  int n,
  sqlite3_tokenizer_cursor **ppCsr
){
  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
  sqlite3_tokenizer_cursor *pCsr = 0;
  int rc;

  rc = pModule->xOpen(pTokenizer, z, n, &pCsr);
  assert( rc==SQLITE_OK || pCsr==0 );
  if( rc==SQLITE_OK ){
    pCsr->pTokenizer = pTokenizer;
    if( pModule->iVersion>=1 ){
      rc = pModule->xLanguageid(pCsr, iLangid);
      if( rc!=SQLITE_OK ){
        pModule->xClose(pCsr);
        pCsr = 0;
      }
    }
  }
  *ppCsr = pCsr;
  return rc;
}

/*
** Function getNextNode(), which is called by fts3ExprParse(), may itself
** call fts3ExprParse(). So this forward declaration is required.
*/
static int fts3ExprParse(ParseContext *, const char *, int, Fts3Expr **, int *);

/*
** Search buffer z[], size n, for a '"' character. Or, if enable_parenthesis
** is defined, search for '(' and ')' as well. Return the index of the first
** such character in the buffer. If there is no such character, return -1.
*/
static int findBarredChar(const char *z, int n){
  int ii;
  for(ii=0; ii<n; ii++){
    if( (z[ii]=='"')
     || (sqlite3_fts3_enable_parentheses && (z[ii]=='(' || z[ii]==')'))
    ){
      return ii;
    }
  }
  return -1;
}

/*
** Extract the next token from buffer z (length n) using the tokenizer
** and other information (column names etc.) in pParse. Create an Fts3Expr
** structure of type FTSQUERY_PHRASE containing a phrase consisting of this
** single token and set *ppExpr to point to it. If the end of the buffer is
** reached before a token is found, set *ppExpr to zero. It is the
** responsibility of the caller to eventually deallocate the allocated
** Fts3Expr structure (if any) by passing it to sqlite3_free().
**
** Return SQLITE_OK if successful, or SQLITE_NOMEM if a memory allocation
** fails.
*/
static int getNextToken(
  ParseContext *pParse,                   /* fts3 query parse context */
  int iCol,                               /* Value for Fts3Phrase.iColumn */
  const char *z, int n,                   /* Input string */
  Fts3Expr **ppExpr,                      /* OUT: expression */
  int *pnConsumed                         /* OUT: Number of bytes consumed */
){
  sqlite3_tokenizer *pTokenizer = pParse->pTokenizer;
  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
  int rc;
  sqlite3_tokenizer_cursor *pCursor;
  Fts3Expr *pRet = 0;

  *pnConsumed = n;
  rc = sqlite3Fts3OpenTokenizer(pTokenizer, pParse->iLangid, z, n, &pCursor);
  if( rc==SQLITE_OK ){
    const char *zToken;
    int nToken = 0, iStart = 0, iEnd = 0, iPosition = 0;
    sqlite3_int64 nByte;                    /* total space to allocate */

    rc = pModule->xNext(pCursor, &zToken, &nToken, &iStart, &iEnd, &iPosition);
    if( rc==SQLITE_OK ){
      /* Check that this tokenization did not gobble up any " characters. Or,
      ** if enable_parenthesis is true, that it did not gobble up any
      ** open or close parenthesis characters either. If it did, call
      ** getNextToken() again, but pass only that part of the input buffer
      ** up to the first such character.  */
      int iBarred = findBarredChar(z, iEnd);
      if( iBarred>=0 ){
        pModule->xClose(pCursor);
        return getNextToken(pParse, iCol, z, iBarred, ppExpr, pnConsumed);
      }

      nByte = sizeof(Fts3Expr) + SZ_FTS3PHRASE(1) + nToken;
      pRet = (Fts3Expr *)sqlite3Fts3MallocZero(nByte);
      if( !pRet ){
        rc = SQLITE_NOMEM;
      }else{
        pRet->eType = FTSQUERY_PHRASE;
        pRet->pPhrase = (Fts3Phrase *)&pRet[1];
        pRet->pPhrase->nToken = 1;
        pRet->pPhrase->iColumn = iCol;
        pRet->pPhrase->aToken[0].n = nToken;
        pRet->pPhrase->aToken[0].z = (char*)&pRet->pPhrase->aToken[1];
        memcpy(pRet->pPhrase->aToken[0].z, zToken, nToken);

        if( iEnd<n && z[iEnd]=='*' ){
          pRet->pPhrase->aToken[0].isPrefix = 1;
          iEnd++;
        }

        while( 1 ){
          if( !sqlite3_fts3_enable_parentheses
           && iStart>0 && z[iStart-1]=='-'
          ){
            pParse->isNot = 1;
            iStart--;
          }else if( pParse->bFts4 && iStart>0 && z[iStart-1]=='^' ){
            pRet->pPhrase->aToken[0].bFirst = 1;
            iStart--;
          }else{
            break;
          }
        }

      }
      *pnConsumed = iEnd;
    }else if( n && rc==SQLITE_DONE ){
      int iBarred = findBarredChar(z, n);
      if( iBarred>=0 ){
        *pnConsumed = iBarred;
      }
      rc = SQLITE_OK;
    }

    pModule->xClose(pCursor);
  }

  *ppExpr = pRet;
  return rc;
}


/*
** Enlarge a memory allocation.  If an out-of-memory allocation occurs,
** then free the old allocation.
*/
static void *fts3ReallocOrFree(void *pOrig, sqlite3_int64 nNew){
  void *pRet = sqlite3_realloc64(pOrig, nNew);
  if( !pRet ){
    sqlite3_free(pOrig);
  }
  return pRet;
}

/*
** Buffer zInput, length nInput, contains the contents of a quoted string
** that appeared as part of an fts3 query expression. Neither quote character
** is included in the buffer. This function attempts to tokenize the entire
** input buffer and create an Fts3Expr structure of type FTSQUERY_PHRASE
** containing the results.
**
** If successful, SQLITE_OK is returned and *ppExpr set to point at the
** allocated Fts3Expr structure. Otherwise, either SQLITE_NOMEM (out of memory
** error) or SQLITE_ERROR (tokenization error) is returned and *ppExpr set
** to 0.
*/
static int getNextString(
  ParseContext *pParse,                   /* fts3 query parse context */
  const char *zInput, int nInput,         /* Input string */
  Fts3Expr **ppExpr                       /* OUT: expression */
){
  sqlite3_tokenizer *pTokenizer = pParse->pTokenizer;
  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
  int rc;
  Fts3Expr *p = 0;
  sqlite3_tokenizer_cursor *pCursor = 0;
  char *zTemp = 0;
  i64 nTemp = 0;

  const int nSpace = sizeof(Fts3Expr) + SZ_FTS3PHRASE(1);
  int nToken = 0;

  /* The final Fts3Expr data structure, including the Fts3Phrase,
  ** Fts3PhraseToken structures token buffers are all stored as a single
  ** allocation so that the expression can be freed with a single call to
  ** sqlite3_free(). Setting this up requires a two pass approach.
  **
  ** The first pass, in the block below, uses a tokenizer cursor to iterate
  ** through the tokens in the expression. This pass uses fts3ReallocOrFree()
  ** to assemble data in two dynamic buffers:
  **
  **   Buffer p: Points to the Fts3Expr structure, followed by the Fts3Phrase
  **             structure, followed by the array of Fts3PhraseToken
  **             structures. This pass only populates the Fts3PhraseToken array.
  **
  **   Buffer zTemp: Contains copies of all tokens.
  **
  ** The second pass, in the block that begins "if( rc==SQLITE_DONE )" below,
  ** appends buffer zTemp to buffer p, and fills in the Fts3Expr and Fts3Phrase
  ** structures.
  */
  rc = sqlite3Fts3OpenTokenizer(
      pTokenizer, pParse->iLangid, zInput, nInput, &pCursor);
  if( rc==SQLITE_OK ){
    int ii;
    for(ii=0; rc==SQLITE_OK; ii++){
      const char *zByte;
      int nByte = 0, iBegin = 0, iEnd = 0, iPos = 0;
      rc = pModule->xNext(pCursor, &zByte, &nByte, &iBegin, &iEnd, &iPos);
      if( rc==SQLITE_OK ){
        Fts3PhraseToken *pToken;

        p = fts3ReallocOrFree(p, nSpace + ii*sizeof(Fts3PhraseToken));
        zTemp = fts3ReallocOrFree(zTemp, nTemp + nByte);
        if( !zTemp || !p ){
          rc = SQLITE_NOMEM;
          goto getnextstring_out;
        }

        assert( nToken==ii );
        pToken = &((Fts3Phrase *)(&p[1]))->aToken[ii];
        memset(pToken, 0, sizeof(Fts3PhraseToken));

        memcpy(&zTemp[nTemp], zByte, nByte);
        nTemp += nByte;

        pToken->n = nByte;
        pToken->isPrefix = (iEnd<nInput && zInput[iEnd]=='*');
        pToken->bFirst = (iBegin>0 && zInput[iBegin-1]=='^');
        nToken = ii+1;
      }
    }
  }

  if( rc==SQLITE_DONE ){
    int jj;
    char *zBuf = 0;

    p = fts3ReallocOrFree(p, nSpace + nToken*sizeof(Fts3PhraseToken) + nTemp);
    if( !p ){
      rc = SQLITE_NOMEM;
      goto getnextstring_out;
    }
    memset(p, 0, (char *)&(((Fts3Phrase *)&p[1])->aToken[0])-(char *)p);
    p->eType = FTSQUERY_PHRASE;
    p->pPhrase = (Fts3Phrase *)&p[1];
    p->pPhrase->iColumn = pParse->iDefaultCol;
    p->pPhrase->nToken = nToken;

sqlite3.c  view on Meta::CPAN

    memcpy((void*)new_elem->pKey, pKey, nKey);
  }else{
    new_elem->pKey = (void*)pKey;
  }
  new_elem->nKey = nKey;
  pH->count++;
  assert( pH->htsize>0 );
  assert( (pH->htsize & (pH->htsize-1))==0 );
  h = hraw & (pH->htsize-1);
  fts3HashInsertElement(pH, &pH->ht[h], new_elem);
  new_elem->data = data;
  return 0;
}

#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */

/************** End of fts3_hash.c *******************************************/
/************** Begin file fts3_porter.c *************************************/
/*
** 2006 September 30
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Implementation of the full-text-search tokenizer that implements
** a Porter stemmer.
*/

/*
** The code in this file is only compiled if:
**
**     * The FTS3 module is being built as an extension
**       (in which case SQLITE_CORE is not defined), or
**
**     * The FTS3 module is being built into the core of
**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
*/
/* #include "fts3Int.h" */
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)

/* #include <assert.h> */
/* #include <stdlib.h> */
/* #include <stdio.h> */
/* #include <string.h> */

/* #include "fts3_tokenizer.h" */

/*
** Class derived from sqlite3_tokenizer
*/
typedef struct porter_tokenizer {
  sqlite3_tokenizer base;      /* Base class */
} porter_tokenizer;

/*
** Class derived from sqlite3_tokenizer_cursor
*/
typedef struct porter_tokenizer_cursor {
  sqlite3_tokenizer_cursor base;
  const char *zInput;          /* input we are tokenizing */
  int nInput;                  /* size of the input */
  int iOffset;                 /* current position in zInput */
  int iToken;                  /* index of next token to be returned */
  char *zToken;                /* storage for current token */
  int nAllocated;              /* space allocated to zToken buffer */
} porter_tokenizer_cursor;


/*
** Create a new tokenizer instance.
*/
static int porterCreate(
  int argc, const char * const *argv,
  sqlite3_tokenizer **ppTokenizer
){
  porter_tokenizer *t;

  UNUSED_PARAMETER(argc);
  UNUSED_PARAMETER(argv);

  t = (porter_tokenizer *) sqlite3_malloc(sizeof(*t));
  if( t==NULL ) return SQLITE_NOMEM;
  memset(t, 0, sizeof(*t));
  *ppTokenizer = &t->base;
  return SQLITE_OK;
}

/*
** Destroy a tokenizer
*/
static int porterDestroy(sqlite3_tokenizer *pTokenizer){
  sqlite3_free(pTokenizer);
  return SQLITE_OK;
}

/*
** Prepare to begin tokenizing a particular string.  The input
** string to be tokenized is zInput[0..nInput-1].  A cursor
** used to incrementally tokenize this string is returned in
** *ppCursor.
*/
static int porterOpen(
  sqlite3_tokenizer *pTokenizer,         /* The tokenizer */
  const char *zInput, int nInput,        /* String to be tokenized */
  sqlite3_tokenizer_cursor **ppCursor    /* OUT: Tokenization cursor */
){
  porter_tokenizer_cursor *c;

  UNUSED_PARAMETER(pTokenizer);

  c = (porter_tokenizer_cursor *) sqlite3_malloc(sizeof(*c));
  if( c==NULL ) return SQLITE_NOMEM;

  c->zInput = zInput;
  if( zInput==0 ){
    c->nInput = 0;
  }else if( nInput<0 ){
    c->nInput = (int)strlen(zInput);
  }else{
    c->nInput = nInput;
  }
  c->iOffset = 0;                 /* start tokenizing at the beginning */
  c->iToken = 0;
  c->zToken = NULL;               /* no space allocated, yet. */
  c->nAllocated = 0;

  *ppCursor = &c->base;
  return SQLITE_OK;
}

/*
** Close a tokenization cursor previously opened by a call to
** porterOpen() above.
*/
static int porterClose(sqlite3_tokenizer_cursor *pCursor){
  porter_tokenizer_cursor *c = (porter_tokenizer_cursor *) pCursor;
  sqlite3_free(c->zToken);
  sqlite3_free(c);
  return SQLITE_OK;
}
/*
** Vowel or consonant
*/
static const char cType[] = {
   0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0,
   1, 1, 1, 2, 1
};

/*
** isConsonant() and isVowel() determine if their first character in
** the string they point to is a consonant or a vowel, according
** to Porter ruls.
**
** A consonate is any letter other than 'a', 'e', 'i', 'o', or 'u'.
** 'Y' is a consonant unless it follows another consonant,
** in which case it is a vowel.
**
** In these routine, the letters are in reverse order.  So the 'y' rule
** is that 'y' is a consonant unless it is followed by another
** consonent.
*/
static int isVowel(const char*);
static int isConsonant(const char *z){
  int j;
  char x = *z;
  if( x==0 ) return 0;
  assert( x>='a' && x<='z' );
  j = cType[x-'a'];
  if( j<2 ) return j;
  return z[1]==0 || isVowel(z + 1);
}
static int isVowel(const char *z){
  int j;
  char x = *z;
  if( x==0 ) return 0;
  assert( x>='a' && x<='z' );
  j = cType[x-'a'];
  if( j<2 ) return 1-j;
  return isConsonant(z + 1);
}

/*
** Let any sequence of one or more vowels be represented by V and let
** C be sequence of one or more consonants.  Then every word can be
** represented as:
**
**           [C] (VC){m} [V]
**
** In prose:  A word is an optional consonant followed by zero or
** vowel-consonant pairs followed by an optional vowel.  "m" is the
** number of vowel consonant pairs.  This routine computes the value
** of m for the first i bytes of a word.
**
** Return true if the m-value for z is 1 or more.  In other words,
** return true if z contains at least one vowel that is followed
** by a consonant.

sqlite3.c  view on Meta::CPAN

     break;
   case 't':
     if( !stem(&z, "eta", "", m_gt_1) ){
       stem(&z, "iti", "", m_gt_1);
     }
     break;
   case 'u':
     if( z[0]=='s' && z[2]=='o' && m_gt_1(z+3) ){
       z += 3;
     }
     break;
   case 'v':
   case 'z':
     if( z[0]=='e' && z[2]=='i' && m_gt_1(z+3) ){
       z += 3;
     }
     break;
  }

  /* Step 5a */
  if( z[0]=='e' ){
    if( m_gt_1(z+1) ){
      z++;
    }else if( m_eq_1(z+1) && !star_oh(z+1) ){
      z++;
    }
  }

  /* Step 5b */
  if( m_gt_1(z) && z[0]=='l' && z[1]=='l' ){
    z++;
  }

  /* z[] is now the stemmed word in reverse order.  Flip it back
  ** around into forward order and return.
  */
  *pnOut = i = (int)strlen(z);
  zOut[i] = 0;
  while( *z ){
    zOut[--i] = *(z++);
  }
}

/*
** Characters that can be part of a token.  We assume any character
** whose value is greater than 0x80 (any UTF character) can be
** part of a token.  In other words, delimiters all must have
** values of 0x7f or lower.
*/
static const char porterIdChar[] = {
/* x0 x1 x2 x3 x4 x5 x6 x7 x8 x9 xA xB xC xD xE xF */
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
    0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
};
#define isDelim(C) (((ch=C)&0x80)==0 && (ch<0x30 || !porterIdChar[ch-0x30]))

/*
** Extract the next token from a tokenization cursor.  The cursor must
** have been opened by a prior call to porterOpen().
*/
static int porterNext(
  sqlite3_tokenizer_cursor *pCursor,  /* Cursor returned by porterOpen */
  const char **pzToken,               /* OUT: *pzToken is the token text */
  int *pnBytes,                       /* OUT: Number of bytes in token */
  int *piStartOffset,                 /* OUT: Starting offset of token */
  int *piEndOffset,                   /* OUT: Ending offset of token */
  int *piPosition                     /* OUT: Position integer of token */
){
  porter_tokenizer_cursor *c = (porter_tokenizer_cursor *) pCursor;
  const char *z = c->zInput;

  while( c->iOffset<c->nInput ){
    int iStartOffset, ch;

    /* Scan past delimiter characters */
    while( c->iOffset<c->nInput && isDelim(z[c->iOffset]) ){
      c->iOffset++;
    }

    /* Count non-delimiter characters. */
    iStartOffset = c->iOffset;
    while( c->iOffset<c->nInput && !isDelim(z[c->iOffset]) ){
      c->iOffset++;
    }

    if( c->iOffset>iStartOffset ){
      int n = c->iOffset-iStartOffset;
      if( n>c->nAllocated ){
        char *pNew;
        c->nAllocated = n+20;
        pNew = sqlite3_realloc64(c->zToken, c->nAllocated);
        if( !pNew ) return SQLITE_NOMEM;
        c->zToken = pNew;
      }
      porter_stemmer(&z[iStartOffset], n, c->zToken, pnBytes);
      *pzToken = c->zToken;
      *piStartOffset = iStartOffset;
      *piEndOffset = c->iOffset;
      *piPosition = c->iToken++;
      return SQLITE_OK;
    }
  }
  return SQLITE_DONE;
}

/*
** The set of routines that implement the porter-stemmer tokenizer
*/
static const sqlite3_tokenizer_module porterTokenizerModule = {
  0,
  porterCreate,
  porterDestroy,
  porterOpen,
  porterClose,
  porterNext,
  0
};

/*
** Allocate a new porter tokenizer.  Return a pointer to the new
** tokenizer in *ppModule
*/
SQLITE_PRIVATE void sqlite3Fts3PorterTokenizerModule(
  sqlite3_tokenizer_module const**ppModule
){
  *ppModule = &porterTokenizerModule;
}

#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */

sqlite3.c  view on Meta::CPAN

      }
      aArg = aNew;
      aArg[iArg++] = z;
      z[n] = '\0';
      sqlite3Fts3Dequote(z);
      z = &z[n+1];
    }
    rc = m->xCreate(iArg, aArg, ppTok);
    assert( rc!=SQLITE_OK || *ppTok );
    if( rc!=SQLITE_OK ){
      sqlite3Fts3ErrMsg(pzErr, "unknown tokenizer");
    }else{
      (*ppTok)->pModule = m;
    }
    sqlite3_free((void *)aArg);
  }

  sqlite3_free(zCopy);
  return rc;
}


#ifdef SQLITE_TEST

#include "tclsqlite.h"
/* #include <string.h> */

/*
** Implementation of a special SQL scalar function for testing tokenizers
** designed to be used in concert with the Tcl testing framework. This
** function must be called with two or more arguments:
**
**   SELECT <function-name>(<key-name>, ..., <input-string>);
**
** where <function-name> is the name passed as the second argument
** to the sqlite3Fts3InitHashTable() function (e.g. 'fts3_tokenizer')
** concatenated with the string '_test' (e.g. 'fts3_tokenizer_test').
**
** The return value is a string that may be interpreted as a Tcl
** list. For each token in the <input-string>, three elements are
** added to the returned list. The first is the token position, the
** second is the token text (folded, stemmed, etc.) and the third is the
** substring of <input-string> associated with the token. For example,
** using the built-in "simple" tokenizer:
**
**   SELECT fts_tokenizer_test('simple', 'I don't see how');
**
** will return the string:
**
**   "{0 i I 1 dont don't 2 see see 3 how how}"
**
*/
static void testFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  Fts3Hash *pHash;
  sqlite3_tokenizer_module *p;
  sqlite3_tokenizer *pTokenizer = 0;
  sqlite3_tokenizer_cursor *pCsr = 0;

  const char *zErr = 0;

  const char *zName;
  int nName;
  const char *zInput;
  int nInput;

  const char *azArg[64];

  const char *zToken;
  int nToken = 0;
  int iStart = 0;
  int iEnd = 0;
  int iPos = 0;
  int i;

  Tcl_Obj *pRet;

  if( argc<2 ){
    sqlite3_result_error(context, "insufficient arguments", -1);
    return;
  }

  nName = sqlite3_value_bytes(argv[0]);
  zName = (const char *)sqlite3_value_text(argv[0]);
  nInput = sqlite3_value_bytes(argv[argc-1]);
  zInput = (const char *)sqlite3_value_text(argv[argc-1]);

  pHash = (Fts3Hash *)sqlite3_user_data(context);
  p = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zName, nName+1);

  if( !p ){
    char *zErr2 = sqlite3_mprintf("unknown tokenizer: %s", zName);
    sqlite3_result_error(context, zErr2, -1);
    sqlite3_free(zErr2);
    return;
  }

  pRet = Tcl_NewObj();
  Tcl_IncrRefCount(pRet);

  for(i=1; i<argc-1; i++){
    azArg[i-1] = (const char *)sqlite3_value_text(argv[i]);
  }

  if( SQLITE_OK!=p->xCreate(argc-2, azArg, &pTokenizer) ){
    zErr = "error in xCreate()";
    goto finish;
  }
  pTokenizer->pModule = p;
  if( sqlite3Fts3OpenTokenizer(pTokenizer, 0, zInput, nInput, &pCsr) ){
    zErr = "error in xOpen()";
    goto finish;
  }

  while( SQLITE_OK==p->xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos) ){
    Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(iPos));
    Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
    zToken = &zInput[iStart];

sqlite3.c  view on Meta::CPAN

#ifdef SQLITE_TEST
  if( SQLITE_OK==rc ){
    rc = sqlite3_create_function(db, zTest, -1, any, p, testFunc, 0, 0);
  }
  if( SQLITE_OK==rc ){
    rc = sqlite3_create_function(db, zTest2, 0, any, pdb, intTestFunc, 0, 0);
  }
#endif

#ifdef SQLITE_TEST
  sqlite3_free(zTest);
  sqlite3_free(zTest2);
#endif

  return rc;
}

#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */

/************** End of fts3_tokenizer.c **************************************/
/************** Begin file fts3_tokenizer1.c *********************************/
/*
** 2006 Oct 10
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** Implementation of the "simple" full-text-search tokenizer.
*/

/*
** The code in this file is only compiled if:
**
**     * The FTS3 module is being built as an extension
**       (in which case SQLITE_CORE is not defined), or
**
**     * The FTS3 module is being built into the core of
**       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
*/
/* #include "fts3Int.h" */
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)

/* #include <assert.h> */
/* #include <stdlib.h> */
/* #include <stdio.h> */
/* #include <string.h> */

/* #include "fts3_tokenizer.h" */

typedef struct simple_tokenizer {
  sqlite3_tokenizer base;
  char delim[128];             /* flag ASCII delimiters */
} simple_tokenizer;

typedef struct simple_tokenizer_cursor {
  sqlite3_tokenizer_cursor base;
  const char *pInput;          /* input we are tokenizing */
  int nBytes;                  /* size of the input */
  int iOffset;                 /* current position in pInput */
  int iToken;                  /* index of next token to be returned */
  char *pToken;                /* storage for current token */
  int nTokenAllocated;         /* space allocated to zToken buffer */
} simple_tokenizer_cursor;


static int simpleDelim(simple_tokenizer *t, unsigned char c){
  return c<0x80 && t->delim[c];
}
static int fts3_isalnum(int x){
  return (x>='0' && x<='9') || (x>='A' && x<='Z') || (x>='a' && x<='z');
}

/*
** Create a new tokenizer instance.
*/
static int simpleCreate(
  int argc, const char * const *argv,
  sqlite3_tokenizer **ppTokenizer
){
  simple_tokenizer *t;

  t = (simple_tokenizer *) sqlite3_malloc(sizeof(*t));
  if( t==NULL ) return SQLITE_NOMEM;
  memset(t, 0, sizeof(*t));

  /* TODO(shess) Delimiters need to remain the same from run to run,
  ** else we need to reindex.  One solution would be a meta-table to
  ** track such information in the database, then we'd only want this
  ** information on the initial create.
  */
  if( argc>1 ){
    int i, n = (int)strlen(argv[1]);
    for(i=0; i<n; i++){
      unsigned char ch = argv[1][i];
      /* We explicitly don't support UTF-8 delimiters for now. */
      if( ch>=0x80 ){
        sqlite3_free(t);
        return SQLITE_ERROR;
      }
      t->delim[ch] = 1;
    }
  } else {
    /* Mark non-alphanumeric ASCII characters as delimiters */
    int i;
    for(i=1; i<0x80; i++){
      t->delim[i] = !fts3_isalnum(i) ? -1 : 0;
    }
  }

  *ppTokenizer = &t->base;
  return SQLITE_OK;
}

/*
** Destroy a tokenizer
*/
static int simpleDestroy(sqlite3_tokenizer *pTokenizer){
  sqlite3_free(pTokenizer);
  return SQLITE_OK;
}

/*
** Prepare to begin tokenizing a particular string.  The input
** string to be tokenized is pInput[0..nBytes-1].  A cursor
** used to incrementally tokenize this string is returned in
** *ppCursor.
*/
static int simpleOpen(
  sqlite3_tokenizer *pTokenizer,         /* The tokenizer */
  const char *pInput, int nBytes,        /* String to be tokenized */
  sqlite3_tokenizer_cursor **ppCursor    /* OUT: Tokenization cursor */
){
  simple_tokenizer_cursor *c;

  UNUSED_PARAMETER(pTokenizer);

  c = (simple_tokenizer_cursor *) sqlite3_malloc(sizeof(*c));
  if( c==NULL ) return SQLITE_NOMEM;

  c->pInput = pInput;
  if( pInput==0 ){
    c->nBytes = 0;
  }else if( nBytes<0 ){
    c->nBytes = (int)strlen(pInput);
  }else{
    c->nBytes = nBytes;
  }
  c->iOffset = 0;                 /* start tokenizing at the beginning */
  c->iToken = 0;
  c->pToken = NULL;               /* no space allocated, yet. */
  c->nTokenAllocated = 0;

  *ppCursor = &c->base;
  return SQLITE_OK;
}

/*
** Close a tokenization cursor previously opened by a call to
** simpleOpen() above.
*/
static int simpleClose(sqlite3_tokenizer_cursor *pCursor){
  simple_tokenizer_cursor *c = (simple_tokenizer_cursor *) pCursor;
  sqlite3_free(c->pToken);
  sqlite3_free(c);
  return SQLITE_OK;
}

/*
** Extract the next token from a tokenization cursor.  The cursor must
** have been opened by a prior call to simpleOpen().
*/
static int simpleNext(
  sqlite3_tokenizer_cursor *pCursor,  /* Cursor returned by simpleOpen */
  const char **ppToken,               /* OUT: *ppToken is the token text */
  int *pnBytes,                       /* OUT: Number of bytes in token */
  int *piStartOffset,                 /* OUT: Starting offset of token */
  int *piEndOffset,                   /* OUT: Ending offset of token */
  int *piPosition                     /* OUT: Position integer of token */
){
  simple_tokenizer_cursor *c = (simple_tokenizer_cursor *) pCursor;
  simple_tokenizer *t = (simple_tokenizer *) pCursor->pTokenizer;
  unsigned char *p = (unsigned char *)c->pInput;

  while( c->iOffset<c->nBytes ){
    int iStartOffset;

    /* Scan past delimiter characters */
    while( c->iOffset<c->nBytes && simpleDelim(t, p[c->iOffset]) ){
      c->iOffset++;
    }

    /* Count non-delimiter characters. */
    iStartOffset = c->iOffset;
    while( c->iOffset<c->nBytes && !simpleDelim(t, p[c->iOffset]) ){
      c->iOffset++;
    }

    if( c->iOffset>iStartOffset ){
      int i, n = c->iOffset-iStartOffset;
      if( n>c->nTokenAllocated ){
        char *pNew;
        c->nTokenAllocated = n+20;
        pNew = sqlite3_realloc64(c->pToken, c->nTokenAllocated);
        if( !pNew ) return SQLITE_NOMEM;
        c->pToken = pNew;
      }
      for(i=0; i<n; i++){
        /* TODO(shess) This needs expansion to handle UTF-8
        ** case-insensitivity.
        */
        unsigned char ch = p[iStartOffset+i];
        c->pToken[i] = (char)((ch>='A' && ch<='Z') ? ch-'A'+'a' : ch);
      }
      *ppToken = c->pToken;
      *pnBytes = n;
      *piStartOffset = iStartOffset;
      *piEndOffset = c->iOffset;
      *piPosition = c->iToken++;

      return SQLITE_OK;
    }
  }
  return SQLITE_DONE;
}

/*
** The set of routines that implement the simple tokenizer
*/
static const sqlite3_tokenizer_module simpleTokenizerModule = {
  0,
  simpleCreate,
  simpleDestroy,
  simpleOpen,
  simpleClose,
  simpleNext,
  0,
};

/*
** Allocate a new simple tokenizer.  Return a pointer to the new

sqlite3.c  view on Meta::CPAN

/************** Begin file fts3_tokenize_vtab.c ******************************/
/*
** 2013 Apr 22
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file contains code for the "fts3tokenize" virtual table module.
** An fts3tokenize virtual table is created as follows:
**
**   CREATE VIRTUAL TABLE <tbl> USING fts3tokenize(
**       <tokenizer-name>, <arg-1>, ...
**   );
**
** The table created has the following schema:
**
**   CREATE TABLE <tbl>(input, token, start, end, position)
**
** When queried, the query must include a WHERE clause of type:
**
**   input = <string>
**
** The virtual table module tokenizes this <string>, using the FTS3
** tokenizer specified by the arguments to the CREATE VIRTUAL TABLE
** statement and returns one row for each token in the result. With
** fields set as follows:
**
**   input:   Always set to a copy of <string>
**   token:   A token from the input.
**   start:   Byte offset of the token within the input <string>.
**   end:     Byte offset of the byte immediately following the end of the
**            token within the input string.
**   pos:     Token offset of token within input.
**
*/
/* #include "fts3Int.h" */
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)

/* #include <string.h> */
/* #include <assert.h> */

typedef struct Fts3tokTable Fts3tokTable;
typedef struct Fts3tokCursor Fts3tokCursor;

/*
** Virtual table structure.
*/
struct Fts3tokTable {
  sqlite3_vtab base;              /* Base class used by SQLite core */
  const sqlite3_tokenizer_module *pMod;
  sqlite3_tokenizer *pTok;
};

/*
** Virtual table cursor structure.
*/
struct Fts3tokCursor {
  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
  char *zInput;                   /* Input string */
  sqlite3_tokenizer_cursor *pCsr; /* Cursor to iterate through zInput */
  int iRowid;                     /* Current 'rowid' value */
  const char *zToken;             /* Current 'token' value */
  int nToken;                     /* Size of zToken in bytes */
  int iStart;                     /* Current 'start' value */
  int iEnd;                       /* Current 'end' value */
  int iPos;                       /* Current 'pos' value */
};

/*
** Query FTS for the tokenizer implementation named zName.
*/
static int fts3tokQueryTokenizer(
  Fts3Hash *pHash,
  const char *zName,
  const sqlite3_tokenizer_module **pp,
  char **pzErr
){
  sqlite3_tokenizer_module *p;
  int nName = (int)strlen(zName);

  p = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zName, nName+1);
  if( !p ){
    sqlite3Fts3ErrMsg(pzErr, "unknown tokenizer: %s", zName);
    return SQLITE_ERROR;
  }

  *pp = p;
  return SQLITE_OK;
}

/*
** The second argument, argv[], is an array of pointers to nul-terminated
** strings. This function makes a copy of the array and strings into a
** single block of memory. It then dequotes any of the strings that appear
** to be quoted.
**
** If successful, output parameter *pazDequote is set to point at the
** array of dequoted strings and SQLITE_OK is returned. The caller is
** responsible for eventually calling sqlite3_free() to free the array
** in this case. Or, if an error occurs, an SQLite error code is returned.
** The final value of *pazDequote is undefined in this case.
*/
static int fts3tokDequoteArray(
  int argc,                       /* Number of elements in argv[] */
  const char * const *argv,       /* Input array */
  char ***pazDequote              /* Output array */
){
  int rc = SQLITE_OK;             /* Return code */
  if( argc==0 ){
    *pazDequote = 0;
  }else{
    int i;
    int nByte = 0;
    char **azDequote;

    for(i=0; i<argc; i++){
      nByte += (int)(strlen(argv[i]) + 1);
    }

    *pazDequote = azDequote = sqlite3_malloc64(sizeof(char *)*argc + nByte);

sqlite3.c  view on Meta::CPAN

  }

  if( rc==SQLITE_OK ){
    memset(pTab, 0, sizeof(Fts3tokTable));
    pTab->pMod = pMod;
    pTab->pTok = pTok;
    *ppVtab = &pTab->base;
  }else{
    if( pTok ){
      pMod->xDestroy(pTok);
    }
  }

  sqlite3_free(azDequote);
  return rc;
}

/*
** This function does the work for both the xDisconnect and xDestroy methods.
** These tables have no persistent representation of their own, so xDisconnect
** and xDestroy are identical operations.
*/
static int fts3tokDisconnectMethod(sqlite3_vtab *pVtab){
  Fts3tokTable *pTab = (Fts3tokTable *)pVtab;

  pTab->pMod->xDestroy(pTab->pTok);
  sqlite3_free(pTab);
  return SQLITE_OK;
}

/*
** xBestIndex - Analyze a WHERE and ORDER BY clause.
*/
static int fts3tokBestIndexMethod(
  sqlite3_vtab *pVTab,
  sqlite3_index_info *pInfo
){
  int i;
  UNUSED_PARAMETER(pVTab);

  for(i=0; i<pInfo->nConstraint; i++){
    if( pInfo->aConstraint[i].usable
     && pInfo->aConstraint[i].iColumn==0
     && pInfo->aConstraint[i].op==SQLITE_INDEX_CONSTRAINT_EQ
    ){
      pInfo->idxNum = 1;
      pInfo->aConstraintUsage[i].argvIndex = 1;
      pInfo->aConstraintUsage[i].omit = 1;
      pInfo->estimatedCost = 1;
      return SQLITE_OK;
    }
  }

  pInfo->idxNum = 0;
  assert( pInfo->estimatedCost>1000000.0 );

  return SQLITE_OK;
}

/*
** xOpen - Open a cursor.
*/
static int fts3tokOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
  Fts3tokCursor *pCsr;
  UNUSED_PARAMETER(pVTab);

  pCsr = (Fts3tokCursor *)sqlite3_malloc(sizeof(Fts3tokCursor));
  if( pCsr==0 ){
    return SQLITE_NOMEM;
  }
  memset(pCsr, 0, sizeof(Fts3tokCursor));

  *ppCsr = (sqlite3_vtab_cursor *)pCsr;
  return SQLITE_OK;
}

/*
** Reset the tokenizer cursor passed as the only argument. As if it had
** just been returned by fts3tokOpenMethod().
*/
static void fts3tokResetCursor(Fts3tokCursor *pCsr){
  if( pCsr->pCsr ){
    Fts3tokTable *pTab = (Fts3tokTable *)(pCsr->base.pVtab);
    pTab->pMod->xClose(pCsr->pCsr);
    pCsr->pCsr = 0;
  }
  sqlite3_free(pCsr->zInput);
  pCsr->zInput = 0;
  pCsr->zToken = 0;
  pCsr->nToken = 0;
  pCsr->iStart = 0;
  pCsr->iEnd = 0;
  pCsr->iPos = 0;
  pCsr->iRowid = 0;
}

/*
** xClose - Close a cursor.
*/
static int fts3tokCloseMethod(sqlite3_vtab_cursor *pCursor){
  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;

  fts3tokResetCursor(pCsr);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

/*
** xNext - Advance the cursor to the next row, if any.
*/
static int fts3tokNextMethod(sqlite3_vtab_cursor *pCursor){
  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
  Fts3tokTable *pTab = (Fts3tokTable *)(pCursor->pVtab);
  int rc;                         /* Return code */

  pCsr->iRowid++;
  rc = pTab->pMod->xNext(pCsr->pCsr,
      &pCsr->zToken, &pCsr->nToken,
      &pCsr->iStart, &pCsr->iEnd, &pCsr->iPos
  );

  if( rc!=SQLITE_OK ){
    fts3tokResetCursor(pCsr);
    if( rc==SQLITE_DONE ) rc = SQLITE_OK;
  }

  return rc;
}

/*
** xFilter - Initialize a cursor to point at the start of its data.
*/
static int fts3tokFilterMethod(
  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
  int idxNum,                     /* Strategy index */
  const char *idxStr,             /* Unused */
  int nVal,                       /* Number of elements in apVal */
  sqlite3_value **apVal           /* Arguments for the indexing scheme */
){
  int rc = SQLITE_ERROR;
  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
  Fts3tokTable *pTab = (Fts3tokTable *)(pCursor->pVtab);
  UNUSED_PARAMETER(idxStr);
  UNUSED_PARAMETER(nVal);

  fts3tokResetCursor(pCsr);
  if( idxNum==1 ){
    const char *zByte = (const char *)sqlite3_value_text(apVal[0]);
    sqlite3_int64 nByte = sqlite3_value_bytes(apVal[0]);
    pCsr->zInput = sqlite3_malloc64(nByte+1);
    if( pCsr->zInput==0 ){
      rc = SQLITE_NOMEM;
    }else{
      if( nByte>0 ) memcpy(pCsr->zInput, zByte, nByte);
      pCsr->zInput[nByte] = 0;
      rc = pTab->pMod->xOpen(pTab->pTok, pCsr->zInput, nByte, &pCsr->pCsr);
      if( rc==SQLITE_OK ){
        pCsr->pCsr->pTokenizer = pTab->pTok;
      }
    }
  }

  if( rc!=SQLITE_OK ) return rc;
  return fts3tokNextMethod(pCursor);
}

/*
** xEof - Return true if the cursor is at EOF, or false otherwise.
*/
static int fts3tokEofMethod(sqlite3_vtab_cursor *pCursor){
  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
  return (pCsr->zToken==0);
}

/*
** xColumn - Return a column value.
*/
static int fts3tokColumnMethod(
  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
  int iCol                        /* Index of column to read value from */
){
  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;

  /* CREATE TABLE x(input, token, start, end, position) */
  switch( iCol ){
    case 0:
      sqlite3_result_text(pCtx, pCsr->zInput, -1, SQLITE_TRANSIENT);
      break;
    case 1:
      sqlite3_result_text(pCtx, pCsr->zToken, pCsr->nToken, SQLITE_TRANSIENT);
      break;
    case 2:
      sqlite3_result_int(pCtx, pCsr->iStart);
      break;
    case 3:
      sqlite3_result_int(pCtx, pCsr->iEnd);
      break;
    default:
      assert( iCol==4 );
      sqlite3_result_int(pCtx, pCsr->iPos);
      break;
  }
  return SQLITE_OK;
}

/*
** xRowid - Return the current rowid for the cursor.
*/
static int fts3tokRowidMethod(
  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
  sqlite_int64 *pRowid            /* OUT: Rowid value */
){
  Fts3tokCursor *pCsr = (Fts3tokCursor *)pCursor;
  *pRowid = (sqlite3_int64)pCsr->iRowid;
  return SQLITE_OK;
}

/*
** Register the fts3tok module with database connection db. Return SQLITE_OK
** if successful or an error code if sqlite3_create_module() fails.
*/
SQLITE_PRIVATE int sqlite3Fts3InitTok(sqlite3 *db, Fts3Hash *pHash, void(*xDestroy)(void*)){
  static const sqlite3_module fts3tok_module = {
     0,                           /* iVersion      */
     fts3tokConnectMethod,        /* xCreate       */
     fts3tokConnectMethod,        /* xConnect      */
     fts3tokBestIndexMethod,      /* xBestIndex    */
     fts3tokDisconnectMethod,     /* xDisconnect   */
     fts3tokDisconnectMethod,     /* xDestroy      */
     fts3tokOpenMethod,           /* xOpen         */
     fts3tokCloseMethod,          /* xClose        */
     fts3tokFilterMethod,         /* xFilter       */
     fts3tokNextMethod,           /* xNext         */
     fts3tokEofMethod,            /* xEof          */
     fts3tokColumnMethod,         /* xColumn       */
     fts3tokRowidMethod,          /* xRowid        */
     0,                           /* xUpdate       */
     0,                           /* xBegin        */
     0,                           /* xSync         */
     0,                           /* xCommit       */
     0,                           /* xRollback     */
     0,                           /* xFindFunction */
     0,                           /* xRename       */
     0,                           /* xSavepoint    */
     0,                           /* xRelease      */
     0,                           /* xRollbackTo   */
     0,                           /* xShadowName   */
     0                            /* xIntegrity    */
  };
  int rc;                         /* Return code */

  rc = sqlite3_create_module_v2(
      db, "fts3tokenize", &fts3tok_module, (void*)pHash, xDestroy
  );
  return rc;
}

#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */

/************** End of fts3_tokenize_vtab.c **********************************/
/************** Begin file fts3_write.c **************************************/
/*
** 2009 Oct 23
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.

sqlite3.c  view on Meta::CPAN

** The code is written so that the hard lower-limit for each of these values
** is 1. Clearly such small values would be inefficient, but can be useful
** for testing purposes.
**
** If this module is built with SQLITE_TEST defined, these constants may
** be overridden at runtime for testing purposes. File fts3_test.c contains
** a Tcl interface to read and write the values.
*/
#ifdef SQLITE_TEST
int test_fts3_node_chunksize = (4*1024);
int test_fts3_node_chunk_threshold = (4*1024)*4;
# define FTS3_NODE_CHUNKSIZE       test_fts3_node_chunksize
# define FTS3_NODE_CHUNK_THRESHOLD test_fts3_node_chunk_threshold
#else
# define FTS3_NODE_CHUNKSIZE (4*1024)
# define FTS3_NODE_CHUNK_THRESHOLD (FTS3_NODE_CHUNKSIZE*4)
#endif

/*
** The values that may be meaningfully bound to the :1 parameter in
** statements SQL_REPLACE_STAT and SQL_SELECT_STAT.
*/
#define FTS_STAT_DOCTOTAL      0
#define FTS_STAT_INCRMERGEHINT 1
#define FTS_STAT_AUTOINCRMERGE 2

/*
** If FTS_LOG_MERGES is defined, call sqlite3_log() to report each automatic
** and incremental merge operation that takes place. This is used for
** debugging FTS only, it should not usually be turned on in production
** systems.
*/
#ifdef FTS3_LOG_MERGES
static void fts3LogMerge(int nMerge, sqlite3_int64 iAbsLevel){
  sqlite3_log(SQLITE_OK, "%d-way merge from level %d", nMerge, (int)iAbsLevel);
}
#else
#define fts3LogMerge(x, y)
#endif


typedef struct PendingList PendingList;
typedef struct SegmentNode SegmentNode;
typedef struct SegmentWriter SegmentWriter;

/*
** An instance of the following data structure is used to build doclists
** incrementally. See function fts3PendingListAppend() for details.
*/
struct PendingList {
  int nData;
  char *aData;
  int nSpace;
  sqlite3_int64 iLastDocid;
  sqlite3_int64 iLastCol;
  sqlite3_int64 iLastPos;
};


/*
** Each cursor has a (possibly empty) linked list of the following objects.
*/
struct Fts3DeferredToken {
  Fts3PhraseToken *pToken;        /* Pointer to corresponding expr token */
  int iCol;                       /* Column token must occur in */
  Fts3DeferredToken *pNext;       /* Next in list of deferred tokens */
  PendingList *pList;             /* Doclist is assembled here */
};

/*
** An instance of this structure is used to iterate through the terms on
** a contiguous set of segment b-tree leaf nodes. Although the details of
** this structure are only manipulated by code in this file, opaque handles
** of type Fts3SegReader* are also used by code in fts3.c to iterate through
** terms when querying the full-text index. See functions:
**
**   sqlite3Fts3SegReaderNew()
**   sqlite3Fts3SegReaderFree()
**   sqlite3Fts3SegReaderIterate()
**
** Methods used to manipulate Fts3SegReader structures:
**
**   fts3SegReaderNext()
**   fts3SegReaderFirstDocid()
**   fts3SegReaderNextDocid()
*/
struct Fts3SegReader {
  int iIdx;                       /* Index within level, or 0x7FFFFFFF for PT */
  u8 bLookup;                     /* True for a lookup only */
  u8 rootOnly;                    /* True for a root-only reader */

  sqlite3_int64 iStartBlock;      /* Rowid of first leaf block to traverse */
  sqlite3_int64 iLeafEndBlock;    /* Rowid of final leaf block to traverse */
  sqlite3_int64 iEndBlock;        /* Rowid of final block in segment (or 0) */
  sqlite3_int64 iCurrentBlock;    /* Current leaf block (or 0) */

  char *aNode;                    /* Pointer to node data (or NULL) */
  int nNode;                      /* Size of buffer at aNode (or 0) */
  int nPopulate;                  /* If >0, bytes of buffer aNode[] loaded */
  sqlite3_blob *pBlob;            /* If not NULL, blob handle to read node */

  Fts3HashElem **ppNextElem;

  /* Variables set by fts3SegReaderNext(). These may be read directly
  ** by the caller. They are valid from the time SegmentReaderNew() returns
  ** until SegmentReaderNext() returns something other than SQLITE_OK
  ** (i.e. SQLITE_DONE).
  */
  int nTerm;                      /* Number of bytes in current term */
  char *zTerm;                    /* Pointer to current term */
  int nTermAlloc;                 /* Allocated size of zTerm buffer */
  char *aDoclist;                 /* Pointer to doclist of current entry */
  int nDoclist;                   /* Size of doclist in current entry */

  /* The following variables are used by fts3SegReaderNextDocid() to iterate
  ** through the current doclist (aDoclist/nDoclist).
  */
  char *pOffsetList;
  int nOffsetList;                /* For descending pending seg-readers only */
  sqlite3_int64 iDocid;
};

sqlite3.c  view on Meta::CPAN


/*
** Add an entry to one of the pending-terms hash tables.
*/
static int fts3PendingTermsAddOne(
  Fts3Table *p,
  int iCol,
  int iPos,
  Fts3Hash *pHash,                /* Pending terms hash table to add entry to */
  const char *zToken,
  int nToken
){
  PendingList *pList;
  int rc = SQLITE_OK;

  pList = (PendingList *)fts3HashFind(pHash, zToken, nToken);
  if( pList ){
    p->nPendingData -= (pList->nData + nToken + sizeof(Fts3HashElem));
  }
  if( fts3PendingListAppend(&pList, p->iPrevDocid, iCol, iPos, &rc) ){
    if( pList==fts3HashInsert(pHash, zToken, nToken, pList) ){
      /* Malloc failed while inserting the new entry. This can only
      ** happen if there was no previous entry for this token.
      */
      assert( 0==fts3HashFind(pHash, zToken, nToken) );
      sqlite3_free(pList);
      rc = SQLITE_NOMEM;
    }
  }
  if( rc==SQLITE_OK ){
    p->nPendingData += (pList->nData + nToken + sizeof(Fts3HashElem));
  }
  return rc;
}

/*
** Tokenize the nul-terminated string zText and add all tokens to the
** pending-terms hash-table. The docid used is that currently stored in
** p->iPrevDocid, and the column is specified by argument iCol.
**
** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
*/
static int fts3PendingTermsAdd(
  Fts3Table *p,                   /* Table into which text will be inserted */
  int iLangid,                    /* Language id to use */
  const char *zText,              /* Text of document to be inserted */
  int iCol,                       /* Column into which text is being inserted */
  u32 *pnWord                     /* IN/OUT: Incr. by number tokens inserted */
){
  int rc;
  int iStart = 0;
  int iEnd = 0;
  int iPos = 0;
  int nWord = 0;

  char const *zToken;
  int nToken = 0;

  sqlite3_tokenizer *pTokenizer = p->pTokenizer;
  sqlite3_tokenizer_module const *pModule = pTokenizer->pModule;
  sqlite3_tokenizer_cursor *pCsr;
  int (*xNext)(sqlite3_tokenizer_cursor *pCursor,
      const char**,int*,int*,int*,int*);

  assert( pTokenizer && pModule );

  /* If the user has inserted a NULL value, this function may be called with
  ** zText==0. In this case, add zero token entries to the hash table and
  ** return early. */
  if( zText==0 ){
    *pnWord = 0;
    return SQLITE_OK;
  }

  rc = sqlite3Fts3OpenTokenizer(pTokenizer, iLangid, zText, -1, &pCsr);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  xNext = pModule->xNext;
  while( SQLITE_OK==rc
      && SQLITE_OK==(rc = xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos))
  ){
    int i;
    if( iPos>=nWord ) nWord = iPos+1;

    /* Positions cannot be negative; we use -1 as a terminator internally.
    ** Tokens must have a non-zero length.
    */
    if( iPos<0 || !zToken || nToken<=0 ){
      rc = SQLITE_ERROR;
      break;
    }

    /* Add the term to the terms index */
    rc = fts3PendingTermsAddOne(
        p, iCol, iPos, &p->aIndex[0].hPending, zToken, nToken
    );

    /* Add the term to each of the prefix indexes that it is not too
    ** short for. */
    for(i=1; rc==SQLITE_OK && i<p->nIndex; i++){
      struct Fts3Index *pIndex = &p->aIndex[i];
      if( nToken<pIndex->nPrefix ) continue;
      rc = fts3PendingTermsAddOne(
          p, iCol, iPos, &pIndex->hPending, zToken, pIndex->nPrefix
      );
    }
  }

  pModule->xClose(pCsr);
  *pnWord += nWord;
  return (rc==SQLITE_DONE ? SQLITE_OK : rc);
}

/*
** Calling this function indicates that subsequent calls to
** fts3PendingTermsAdd() are to add term/position-list pairs for the
** contents of the document with docid iDocid.
*/
static int fts3PendingTermsDocid(
  Fts3Table *p,                   /* Full-text table handle */

sqlite3.c  view on Meta::CPAN

          sqlite3_free(aByte);
          aByte = 0;
        }
      }
      *paBlob = aByte;
    }
  }else if( rc==SQLITE_ERROR ){
    rc = FTS_CORRUPT_VTAB;
  }

  return rc;
}

/*
** Close the blob handle at p->pSegments, if it is open. See comments above
** the sqlite3Fts3ReadBlock() function for details.
*/
SQLITE_PRIVATE void sqlite3Fts3SegmentsClose(Fts3Table *p){
  sqlite3_blob_close(p->pSegments);
  p->pSegments = 0;
}

static int fts3SegReaderIncrRead(Fts3SegReader *pReader){
  int nRead;                      /* Number of bytes to read */
  int rc;                         /* Return code */

  nRead = MIN(pReader->nNode - pReader->nPopulate, FTS3_NODE_CHUNKSIZE);
  rc = sqlite3_blob_read(
      pReader->pBlob,
      &pReader->aNode[pReader->nPopulate],
      nRead,
      pReader->nPopulate
  );

  if( rc==SQLITE_OK ){
    pReader->nPopulate += nRead;
    memset(&pReader->aNode[pReader->nPopulate], 0, FTS3_NODE_PADDING);
    if( pReader->nPopulate==pReader->nNode ){
      sqlite3_blob_close(pReader->pBlob);
      pReader->pBlob = 0;
      pReader->nPopulate = 0;
    }
  }
  return rc;
}

static int fts3SegReaderRequire(Fts3SegReader *pReader, char *pFrom, int nByte){
  int rc = SQLITE_OK;
  assert( !pReader->pBlob
       || (pFrom>=pReader->aNode && pFrom<&pReader->aNode[pReader->nNode])
  );
  while( pReader->pBlob && rc==SQLITE_OK
     &&  (pFrom - pReader->aNode + nByte)>pReader->nPopulate
  ){
    rc = fts3SegReaderIncrRead(pReader);
  }
  return rc;
}

/*
** Set an Fts3SegReader cursor to point at EOF.
*/
static void fts3SegReaderSetEof(Fts3SegReader *pSeg){
  if( !fts3SegReaderIsRootOnly(pSeg) ){
    sqlite3_free(pSeg->aNode);
    sqlite3_blob_close(pSeg->pBlob);
    pSeg->pBlob = 0;
  }
  pSeg->aNode = 0;
}

/*
** Move the iterator passed as the first argument to the next term in the
** segment. If successful, SQLITE_OK is returned. If there is no next term,
** SQLITE_DONE. Otherwise, an SQLite error code.
*/
static int fts3SegReaderNext(
  Fts3Table *p,
  Fts3SegReader *pReader,
  int bIncr
){
  int rc;                         /* Return code of various sub-routines */
  char *pNext;                    /* Cursor variable */
  int nPrefix;                    /* Number of bytes in term prefix */
  int nSuffix;                    /* Number of bytes in term suffix */

  if( !pReader->aDoclist ){
    pNext = pReader->aNode;
  }else{
    pNext = &pReader->aDoclist[pReader->nDoclist];
  }

  if( !pNext || pNext>=&pReader->aNode[pReader->nNode] ){

    if( fts3SegReaderIsPending(pReader) ){
      Fts3HashElem *pElem = *(pReader->ppNextElem);
      sqlite3_free(pReader->aNode);
      pReader->aNode = 0;
      if( pElem ){
        char *aCopy;
        PendingList *pList = (PendingList *)fts3HashData(pElem);
        int nCopy = pList->nData+1;

        int nTerm = fts3HashKeysize(pElem);
        if( (nTerm+1)>pReader->nTermAlloc ){
          sqlite3_free(pReader->zTerm);
          pReader->zTerm = (char*)sqlite3_malloc64(((i64)nTerm+1)*2);
          if( !pReader->zTerm ) return SQLITE_NOMEM;
          pReader->nTermAlloc = (nTerm+1)*2;
        }
        memcpy(pReader->zTerm, fts3HashKey(pElem), nTerm);
        pReader->zTerm[nTerm] = '\0';
        pReader->nTerm = nTerm;

        aCopy = (char*)sqlite3_malloc64(nCopy);
        if( !aCopy ) return SQLITE_NOMEM;
        memcpy(aCopy, pList->aData, nCopy);
        pReader->nNode = pReader->nDoclist = nCopy;
        pReader->aNode = pReader->aDoclist = aCopy;
        pReader->ppNextElem++;
        assert( pReader->aNode );

sqlite3.c  view on Meta::CPAN

    }else{
      rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
      sqlite3_free(zSql);
    }

    if( rc==SQLITE_OK ){
      sqlite3_int64 nByte = sizeof(u32) * ((sqlite3_int64)p->nColumn+1)*3;
      aSz = (u32 *)sqlite3_malloc64(nByte);
      if( aSz==0 ){
        rc = SQLITE_NOMEM;
      }else{
        memset(aSz, 0, nByte);
        aSzIns = &aSz[p->nColumn+1];
        aSzDel = &aSzIns[p->nColumn+1];
      }
    }

    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
      int iCol;
      int iLangid = langidFromSelect(p, pStmt);
      rc = fts3PendingTermsDocid(p, 0, iLangid, sqlite3_column_int64(pStmt, 0));
      memset(aSz, 0, sizeof(aSz[0]) * (p->nColumn+1));
      for(iCol=0; rc==SQLITE_OK && iCol<p->nColumn; iCol++){
        if( p->abNotindexed[iCol]==0 ){
          const char *z = (const char *) sqlite3_column_text(pStmt, iCol+1);
          rc = fts3PendingTermsAdd(p, iLangid, z, iCol, &aSz[iCol]);
          aSz[p->nColumn] += sqlite3_column_bytes(pStmt, iCol+1);
        }
      }
      if( p->bHasDocsize ){
        fts3InsertDocsize(&rc, p, aSz);
      }
      if( rc!=SQLITE_OK ){
        sqlite3_finalize(pStmt);
        pStmt = 0;
      }else{
        nEntry++;
        for(iCol=0; iCol<=p->nColumn; iCol++){
          aSzIns[iCol] += aSz[iCol];
        }
      }
    }
    if( p->bFts4 ){
      fts3UpdateDocTotals(&rc, p, aSzIns, aSzDel, nEntry);
    }
    sqlite3_free(aSz);

    if( pStmt ){
      int rc2 = sqlite3_finalize(pStmt);
      if( rc==SQLITE_OK ){
        rc = rc2;
      }
    }
  }

  return rc;
}


/*
** This function opens a cursor used to read the input data for an
** incremental merge operation. Specifically, it opens a cursor to scan
** the oldest nSeg segments (idx=0 through idx=(nSeg-1)) in absolute
** level iAbsLevel.
*/
static int fts3IncrmergeCsr(
  Fts3Table *p,                   /* FTS3 table handle */
  sqlite3_int64 iAbsLevel,        /* Absolute level to open */
  int nSeg,                       /* Number of segments to merge */
  Fts3MultiSegReader *pCsr        /* Cursor object to populate */
){
  int rc;                         /* Return Code */
  sqlite3_stmt *pStmt = 0;        /* Statement used to read %_segdir entry */
  sqlite3_int64 nByte;            /* Bytes allocated at pCsr->apSegment[] */

  /* Allocate space for the Fts3MultiSegReader.aCsr[] array */
  memset(pCsr, 0, sizeof(*pCsr));
  nByte = sizeof(Fts3SegReader *) * nSeg;
  pCsr->apSegment = (Fts3SegReader **)sqlite3_malloc64(nByte);

  if( pCsr->apSegment==0 ){
    rc = SQLITE_NOMEM;
  }else{
    memset(pCsr->apSegment, 0, nByte);
    rc = fts3SqlStmt(p, SQL_SELECT_LEVEL, &pStmt, 0);
  }
  if( rc==SQLITE_OK ){
    int i;
    int rc2;
    sqlite3_bind_int64(pStmt, 1, iAbsLevel);
    assert( pCsr->nSegment==0 );
    for(i=0; rc==SQLITE_OK && sqlite3_step(pStmt)==SQLITE_ROW && i<nSeg; i++){
      rc = sqlite3Fts3SegReaderNew(i, 0,
          sqlite3_column_int64(pStmt, 1),        /* segdir.start_block */
          sqlite3_column_int64(pStmt, 2),        /* segdir.leaves_end_block */
          sqlite3_column_int64(pStmt, 3),        /* segdir.end_block */
          sqlite3_column_blob(pStmt, 4),         /* segdir.root */
          sqlite3_column_bytes(pStmt, 4),        /* segdir.root */
          &pCsr->apSegment[i]
      );
      pCsr->nSegment++;
    }
    rc2 = sqlite3_reset(pStmt);
    if( rc==SQLITE_OK ) rc = rc2;
  }

  return rc;
}

typedef struct IncrmergeWriter IncrmergeWriter;
typedef struct NodeWriter NodeWriter;
typedef struct Blob Blob;
typedef struct NodeReader NodeReader;

/*
** An instance of the following structure is used as a dynamic buffer
** to build up nodes or other blobs of data in.
**
** The function blobGrowBuffer() is used to extend the allocation.
*/
struct Blob {
  char *a;                        /* Pointer to allocation */

sqlite3.c  view on Meta::CPAN

** If the size of the value in blob pPrev is zero, then this is the first
** term written to the node. Otherwise, pPrev contains a copy of the
** previous term. Before this function returns, it is updated to contain a
** copy of zTerm/nTerm.
**
** It is assumed that the buffer associated with pNode is already large
** enough to accommodate the new entry. The buffer associated with pPrev
** is extended by this function if required.
**
** If an error (i.e. OOM condition) occurs, an SQLite error code is
** returned. Otherwise, SQLITE_OK.
*/
static int fts3AppendToNode(
  Blob *pNode,                    /* Current node image to append to */
  Blob *pPrev,                    /* Buffer containing previous term written */
  const char *zTerm,              /* New term to write */
  int nTerm,                      /* Size of zTerm in bytes */
  const char *aDoclist,           /* Doclist (or NULL) to write */
  int nDoclist                    /* Size of aDoclist in bytes */
){
  int rc = SQLITE_OK;             /* Return code */
  int bFirst = (pPrev->n==0);     /* True if this is the first term written */
  int nPrefix;                    /* Size of term prefix in bytes */
  int nSuffix;                    /* Size of term suffix in bytes */

  /* Node must have already been started. There must be a doclist for a
  ** leaf node, and there must not be a doclist for an internal node.  */
  assert( pNode->n>0 );
  assert_fts3_nc( (pNode->a[0]=='\0')==(aDoclist!=0) );

  blobGrowBuffer(pPrev, nTerm, &rc);
  if( rc!=SQLITE_OK ) return rc;
  assert( pPrev!=0 );
  assert( pPrev->a!=0 );

  nPrefix = fts3PrefixCompress(pPrev->a, pPrev->n, zTerm, nTerm);
  nSuffix = nTerm - nPrefix;
  if( nSuffix<=0 ) return FTS_CORRUPT_VTAB;
  memcpy(pPrev->a, zTerm, nTerm);
  pPrev->n = nTerm;

  if( bFirst==0 ){
    pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nPrefix);
  }
  pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nSuffix);
  memcpy(&pNode->a[pNode->n], &zTerm[nPrefix], nSuffix);
  pNode->n += nSuffix;

  if( aDoclist ){
    pNode->n += sqlite3Fts3PutVarint(&pNode->a[pNode->n], nDoclist);
    memcpy(&pNode->a[pNode->n], aDoclist, nDoclist);
    pNode->n += nDoclist;
  }

  assert( pNode->n<=pNode->nAlloc );

  return SQLITE_OK;
}

/*
** Append the current term and doclist pointed to by cursor pCsr to the
** appendable b-tree segment opened for writing by pWriter.
**
** Return SQLITE_OK if successful, or an SQLite error code otherwise.
*/
static int fts3IncrmergeAppend(
  Fts3Table *p,                   /* Fts3 table handle */
  IncrmergeWriter *pWriter,       /* Writer object */
  Fts3MultiSegReader *pCsr        /* Cursor containing term and doclist */
){
  const char *zTerm = pCsr->zTerm;
  int nTerm = pCsr->nTerm;
  const char *aDoclist = pCsr->aDoclist;
  int nDoclist = pCsr->nDoclist;
  int rc = SQLITE_OK;           /* Return code */
  int nSpace;                   /* Total space in bytes required on leaf */
  int nPrefix;                  /* Size of prefix shared with previous term */
  int nSuffix;                  /* Size of suffix (nTerm - nPrefix) */
  NodeWriter *pLeaf;            /* Object used to write leaf nodes */

  pLeaf = &pWriter->aNodeWriter[0];
  nPrefix = fts3PrefixCompress(pLeaf->key.a, pLeaf->key.n, zTerm, nTerm);
  nSuffix = nTerm - nPrefix;
  if(nSuffix<=0 ) return FTS_CORRUPT_VTAB;

  nSpace  = sqlite3Fts3VarintLen(nPrefix);
  nSpace += sqlite3Fts3VarintLen(nSuffix) + nSuffix;
  nSpace += sqlite3Fts3VarintLen(nDoclist) + nDoclist;

  /* If the current block is not empty, and if adding this term/doclist
  ** to the current block would make it larger than Fts3Table.nNodeSize bytes,
  ** and if there is still room for another leaf page, write this block out to
  ** the database. */
  if( pLeaf->block.n>0
   && (pLeaf->block.n + nSpace)>p->nNodeSize
   && pLeaf->iBlock < (pWriter->iStart + pWriter->nLeafEst)
  ){
    rc = fts3WriteSegment(p, pLeaf->iBlock, pLeaf->block.a, pLeaf->block.n);
    pWriter->nWork++;

    /* Add the current term to the parent node. The term added to the
    ** parent must:
    **
    **   a) be greater than the largest term on the leaf node just written
    **      to the database (still available in pLeaf->key), and
    **
    **   b) be less than or equal to the term about to be added to the new
    **      leaf node (zTerm/nTerm).
    **
    ** In other words, it must be the prefix of zTerm 1 byte longer than
    ** the common prefix (if any) of zTerm and pWriter->zTerm.
    */
    if( rc==SQLITE_OK ){
      rc = fts3IncrmergePush(p, pWriter, zTerm, nPrefix+1);
    }

    /* Advance to the next output block */
    pLeaf->iBlock++;
    pLeaf->key.n = 0;
    pLeaf->block.n = 0;

sqlite3.c  view on Meta::CPAN


  while( rc==SQLITE_OK && iBlock ){
    char *aBlock = 0;
    int nBlock = 0;
    iNewStart = iBlock;

    rc = sqlite3Fts3ReadBlock(p, iBlock, &aBlock, &nBlock, 0);
    if( rc==SQLITE_OK ){
      rc = fts3TruncateNode(aBlock, nBlock, &block, zTerm, nTerm, &iBlock);
    }
    if( rc==SQLITE_OK ){
      rc = fts3WriteSegment(p, iNewStart, block.a, block.n);
    }
    sqlite3_free(aBlock);
  }

  /* Variable iNewStart now contains the first valid leaf node. */
  if( rc==SQLITE_OK && iNewStart ){
    sqlite3_stmt *pDel = 0;
    rc = fts3SqlStmt(p, SQL_DELETE_SEGMENTS_RANGE, &pDel, 0);
    if( rc==SQLITE_OK ){
      sqlite3_bind_int64(pDel, 1, iOldStart);
      sqlite3_bind_int64(pDel, 2, iNewStart-1);
      sqlite3_step(pDel);
      rc = sqlite3_reset(pDel);
    }
  }

  if( rc==SQLITE_OK ){
    sqlite3_stmt *pChomp = 0;
    rc = fts3SqlStmt(p, SQL_CHOMP_SEGDIR, &pChomp, 0);
    if( rc==SQLITE_OK ){
      sqlite3_bind_int64(pChomp, 1, iNewStart);
      sqlite3_bind_blob(pChomp, 2, root.a, root.n, SQLITE_STATIC);
      sqlite3_bind_int64(pChomp, 3, iAbsLevel);
      sqlite3_bind_int(pChomp, 4, iIdx);
      sqlite3_step(pChomp);
      rc = sqlite3_reset(pChomp);
      sqlite3_bind_null(pChomp, 2);
    }
  }

  sqlite3_free(root.a);
  sqlite3_free(block.a);
  return rc;
}

/*
** This function is called after an incrmental-merge operation has run to
** merge (or partially merge) two or more segments from absolute level
** iAbsLevel.
**
** Each input segment is either removed from the db completely (if all of
** its data was copied to the output segment by the incrmerge operation)
** or modified in place so that it no longer contains those entries that
** have been duplicated in the output segment.
*/
static int fts3IncrmergeChomp(
  Fts3Table *p,                   /* FTS table handle */
  sqlite3_int64 iAbsLevel,        /* Absolute level containing segments */
  Fts3MultiSegReader *pCsr,       /* Chomp all segments opened by this cursor */
  int *pnRem                      /* Number of segments not deleted */
){
  int i;
  int nRem = 0;
  int rc = SQLITE_OK;

  for(i=pCsr->nSegment-1; i>=0 && rc==SQLITE_OK; i--){
    Fts3SegReader *pSeg = 0;
    int j;

    /* Find the Fts3SegReader object with Fts3SegReader.iIdx==i. It is hiding
    ** somewhere in the pCsr->apSegment[] array.  */
    for(j=0; ALWAYS(j<pCsr->nSegment); j++){
      pSeg = pCsr->apSegment[j];
      if( pSeg->iIdx==i ) break;
    }
    assert( j<pCsr->nSegment && pSeg->iIdx==i );

    if( pSeg->aNode==0 ){
      /* Seg-reader is at EOF. Remove the entire input segment. */
      rc = fts3DeleteSegment(p, pSeg);
      if( rc==SQLITE_OK ){
        rc = fts3RemoveSegdirEntry(p, iAbsLevel, pSeg->iIdx);
      }
      *pnRem = 0;
    }else{
      /* The incremental merge did not copy all the data from this
      ** segment to the upper level. The segment is modified in place
      ** so that it contains no keys smaller than zTerm/nTerm. */
      const char *zTerm = pSeg->zTerm;
      int nTerm = pSeg->nTerm;
      rc = fts3TruncateSegment(p, iAbsLevel, pSeg->iIdx, zTerm, nTerm);
      nRem++;
    }
  }

  if( rc==SQLITE_OK && nRem!=pCsr->nSegment ){
    rc = fts3RepackSegdirLevel(p, iAbsLevel);
  }

  *pnRem = nRem;
  return rc;
}

/*
** Store an incr-merge hint in the database.
*/
static int fts3IncrmergeHintStore(Fts3Table *p, Blob *pHint){
  sqlite3_stmt *pReplace = 0;
  int rc;                         /* Return code */

  rc = fts3SqlStmt(p, SQL_REPLACE_STAT, &pReplace, 0);
  if( rc==SQLITE_OK ){
    sqlite3_bind_int(pReplace, 1, FTS_STAT_INCRMERGEHINT);
    sqlite3_bind_blob(pReplace, 2, pHint->a, pHint->n, SQLITE_STATIC);
    sqlite3_step(pReplace);
    rc = sqlite3_reset(pReplace);
    sqlite3_bind_null(pReplace, 2);
  }

sqlite3.c  view on Meta::CPAN

** and the number of input segments.
**
** If successful, leave *pRc set to SQLITE_OK and return. If an error occurs,
** set *pRc to an SQLite error code before returning.
*/
static void fts3IncrmergeHintPush(
  Blob *pHint,                    /* Hint blob to append to */
  i64 iAbsLevel,                  /* First varint to store in hint */
  int nInput,                     /* Second varint to store in hint */
  int *pRc                        /* IN/OUT: Error code */
){
  blobGrowBuffer(pHint, pHint->n + 2*FTS3_VARINT_MAX, pRc);
  if( *pRc==SQLITE_OK ){
    pHint->n += sqlite3Fts3PutVarint(&pHint->a[pHint->n], iAbsLevel);
    pHint->n += sqlite3Fts3PutVarint(&pHint->a[pHint->n], (i64)nInput);
  }
}

/*
** Read the last entry (most recently pushed) from the hint blob *pHint
** and then remove the entry. Write the two values read to *piAbsLevel and
** *pnInput before returning.
**
** If no error occurs, return SQLITE_OK. If the hint blob in *pHint does
** not contain at least two valid varints, return SQLITE_CORRUPT_VTAB.
*/
static int fts3IncrmergeHintPop(Blob *pHint, i64 *piAbsLevel, int *pnInput){
  const int nHint = pHint->n;
  int i;

  i = pHint->n-1;
  if( (pHint->a[i] & 0x80) ) return FTS_CORRUPT_VTAB;
  while( i>0 && (pHint->a[i-1] & 0x80) ) i--;
  if( i==0 ) return FTS_CORRUPT_VTAB;
  i--;
  while( i>0 && (pHint->a[i-1] & 0x80) ) i--;

  pHint->n = i;
  i += sqlite3Fts3GetVarint(&pHint->a[i], piAbsLevel);
  i += fts3GetVarint32(&pHint->a[i], pnInput);
  assert( i<=nHint );
  if( i!=nHint ) return FTS_CORRUPT_VTAB;

  return SQLITE_OK;
}


/*
** Attempt an incremental merge that writes nMerge leaf blocks.
**
** Incremental merges happen nMin segments at a time. The segments
** to be merged are the nMin oldest segments (the ones with the smallest
** values for the _segdir.idx field) in the highest level that contains
** at least nMin segments. Multiple merges might occur in an attempt to
** write the quota of nMerge leaf blocks.
*/
SQLITE_PRIVATE int sqlite3Fts3Incrmerge(Fts3Table *p, int nMerge, int nMin){
  int rc;                         /* Return code */
  int nRem = nMerge;              /* Number of leaf pages yet to  be written */
  Fts3MultiSegReader *pCsr;       /* Cursor used to read input data */
  Fts3SegFilter *pFilter;         /* Filter used with cursor pCsr */
  IncrmergeWriter *pWriter;       /* Writer object */
  int nSeg = 0;                   /* Number of input segments */
  sqlite3_int64 iAbsLevel = 0;    /* Absolute level number to work on */
  Blob hint = {0, 0, 0};          /* Hint read from %_stat table */
  int bDirtyHint = 0;             /* True if blob 'hint' has been modified */

  /* Allocate space for the cursor, filter and writer objects */
  const int nAlloc = sizeof(*pCsr) + sizeof(*pFilter) + sizeof(*pWriter);
  pWriter = (IncrmergeWriter *)sqlite3_malloc64(nAlloc);
  if( !pWriter ) return SQLITE_NOMEM;
  pFilter = (Fts3SegFilter *)&pWriter[1];
  pCsr = (Fts3MultiSegReader *)&pFilter[1];

  rc = fts3IncrmergeHintLoad(p, &hint);
  while( rc==SQLITE_OK && nRem>0 ){
    const i64 nMod = FTS3_SEGDIR_MAXLEVEL * p->nIndex;
    sqlite3_stmt *pFindLevel = 0; /* SQL used to determine iAbsLevel */
    int bUseHint = 0;             /* True if attempting to append */
    int iIdx = 0;                 /* Largest idx in level (iAbsLevel+1) */

    /* Search the %_segdir table for the absolute level with the smallest
    ** relative level number that contains at least nMin segments, if any.
    ** If one is found, set iAbsLevel to the absolute level number and
    ** nSeg to nMin. If no level with at least nMin segments can be found,
    ** set nSeg to -1.
    */
    rc = fts3SqlStmt(p, SQL_FIND_MERGE_LEVEL, &pFindLevel, 0);
    sqlite3_bind_int(pFindLevel, 1, MAX(2, nMin));
    if( sqlite3_step(pFindLevel)==SQLITE_ROW ){
      iAbsLevel = sqlite3_column_int64(pFindLevel, 0);
      nSeg = sqlite3_column_int(pFindLevel, 1);
      assert( nSeg>=2 );
    }else{
      nSeg = -1;
    }
    rc = sqlite3_reset(pFindLevel);

    /* If the hint read from the %_stat table is not empty, check if the
    ** last entry in it specifies a relative level smaller than or equal
    ** to the level identified by the block above (if any). If so, this
    ** iteration of the loop will work on merging at the hinted level.
    */
    if( rc==SQLITE_OK && hint.n ){
      int nHint = hint.n;
      sqlite3_int64 iHintAbsLevel = 0;      /* Hint level */
      int nHintSeg = 0;                     /* Hint number of segments */

      rc = fts3IncrmergeHintPop(&hint, &iHintAbsLevel, &nHintSeg);
      if( nSeg<0 || (iAbsLevel % nMod) >= (iHintAbsLevel % nMod) ){
        /* Based on the scan in the block above, it is known that there
        ** are no levels with a relative level smaller than that of
        ** iAbsLevel with more than nSeg segments, or if nSeg is -1,
        ** no levels with more than nMin segments. Use this to limit the
        ** value of nHintSeg to avoid a large memory allocation in case the
        ** merge-hint is corrupt*/
        iAbsLevel = iHintAbsLevel;
        nSeg = MIN(MAX(nMin,nSeg), nHintSeg);
        bUseHint = 1;
        bDirtyHint = 1;
      }else{
        /* This undoes the effect of the HintPop() above - so that no entry
        ** is removed from the hint blob.  */
        hint.n = nHint;
      }
    }

    /* If nSeg is less that zero, then there is no level with at least
    ** nMin segments and no hint in the %_stat table. No work to do.
    ** Exit early in this case.  */
    if( nSeg<=0 ) break;

    assert( nMod<=0x7FFFFFFF );
    if( iAbsLevel<0 || iAbsLevel>(nMod<<32) ){
      rc = FTS_CORRUPT_VTAB;
      break;
    }

    /* Open a cursor to iterate through the contents of the oldest nSeg
    ** indexes of absolute level iAbsLevel. If this cursor is opened using
    ** the 'hint' parameters, it is possible that there are less than nSeg
    ** segments available in level iAbsLevel. In this case, no work is
    ** done on iAbsLevel - fall through to the next iteration of the loop
    ** to start work on some other level.  */
    memset(pWriter, 0, nAlloc);
    pFilter->flags = FTS3_SEGMENT_REQUIRE_POS;

    if( rc==SQLITE_OK ){
      rc = fts3IncrmergeOutputIdx(p, iAbsLevel, &iIdx);
      assert( bUseHint==1 || bUseHint==0 );
      if( iIdx==0 || (bUseHint && iIdx==1) ){
        int bIgnore = 0;
        rc = fts3SegmentIsMaxLevel(p, iAbsLevel+1, &bIgnore);
        if( bIgnore ){
          pFilter->flags |= FTS3_SEGMENT_IGNORE_EMPTY;
        }
      }
    }

    if( rc==SQLITE_OK ){
      rc = fts3IncrmergeCsr(p, iAbsLevel, nSeg, pCsr);
    }
    if( SQLITE_OK==rc && pCsr->nSegment==nSeg
     && SQLITE_OK==(rc = sqlite3Fts3SegReaderStart(p, pCsr, pFilter))
    ){
      int bEmpty = 0;
      rc = sqlite3Fts3SegReaderStep(p, pCsr);
      if( rc==SQLITE_OK ){
        bEmpty = 1;
      }else if( rc!=SQLITE_ROW ){
        sqlite3Fts3SegReaderFinish(pCsr);
        break;
      }
      if( bUseHint && iIdx>0 ){
        const char *zKey = pCsr->zTerm;
        int nKey = pCsr->nTerm;
        rc = fts3IncrmergeLoad(p, iAbsLevel, iIdx-1, zKey, nKey, pWriter);
      }else{
        rc = fts3IncrmergeWriter(p, iAbsLevel, iIdx, pCsr, pWriter);
      }

      if( rc==SQLITE_OK && pWriter->nLeafEst ){
        fts3LogMerge(nSeg, iAbsLevel);
        if( bEmpty==0 ){
          do {
            rc = fts3IncrmergeAppend(p, pWriter, pCsr);
            if( rc==SQLITE_OK ) rc = sqlite3Fts3SegReaderStep(p, pCsr);
            if( pWriter->nWork>=nRem && rc==SQLITE_ROW ) rc = SQLITE_OK;
          }while( rc==SQLITE_ROW );
        }

        /* Update or delete the input segments */
        if( rc==SQLITE_OK ){
          nRem -= (1 + pWriter->nWork);
          rc = fts3IncrmergeChomp(p, iAbsLevel, pCsr, &nSeg);
          if( nSeg!=0 ){
            bDirtyHint = 1;
            fts3IncrmergeHintPush(&hint, iAbsLevel, nSeg, &rc);
          }
        }

sqlite3.c  view on Meta::CPAN

  sqlite3Fts3SegReaderFinish(&csr);

  *pRc = rc;
  return cksum;
}

/*
** Check if the contents of the FTS index match the current contents of the
** content table. If no error occurs and the contents do match, set *pbOk
** to true and return SQLITE_OK. Or if the contents do not match, set *pbOk
** to false before returning.
**
** If an error occurs (e.g. an OOM or IO error), return an SQLite error
** code. The final value of *pbOk is undefined in this case.
*/
SQLITE_PRIVATE int sqlite3Fts3IntegrityCheck(Fts3Table *p, int *pbOk){
  int rc = SQLITE_OK;             /* Return code */
  u64 cksum1 = 0;                 /* Checksum based on FTS index contents */
  u64 cksum2 = 0;                 /* Checksum based on %_content contents */
  sqlite3_stmt *pAllLangid = 0;   /* Statement to return all language-ids */

  /* This block calculates the checksum according to the FTS index. */
  rc = fts3SqlStmt(p, SQL_SELECT_ALL_LANGID, &pAllLangid, 0);
  if( rc==SQLITE_OK ){
    int rc2;
    sqlite3_bind_int(pAllLangid, 1, p->iPrevLangid);
    sqlite3_bind_int(pAllLangid, 2, p->nIndex);
    while( rc==SQLITE_OK && sqlite3_step(pAllLangid)==SQLITE_ROW ){
      int iLangid = sqlite3_column_int(pAllLangid, 0);
      int i;
      for(i=0; i<p->nIndex; i++){
        cksum1 = cksum1 ^ fts3ChecksumIndex(p, iLangid, i, &rc);
      }
    }
    rc2 = sqlite3_reset(pAllLangid);
    if( rc==SQLITE_OK ) rc = rc2;
  }

  /* This block calculates the checksum according to the %_content table */
  if( rc==SQLITE_OK ){
    sqlite3_tokenizer_module const *pModule = p->pTokenizer->pModule;
    sqlite3_stmt *pStmt = 0;
    char *zSql;

    zSql = sqlite3_mprintf("SELECT %s" , p->zReadExprlist);
    if( !zSql ){
      rc = SQLITE_NOMEM;
    }else{
      rc = sqlite3_prepare_v2(p->db, zSql, -1, &pStmt, 0);
      sqlite3_free(zSql);
    }

    while( rc==SQLITE_OK && SQLITE_ROW==sqlite3_step(pStmt) ){
      i64 iDocid = sqlite3_column_int64(pStmt, 0);
      int iLang = langidFromSelect(p, pStmt);
      int iCol;

      for(iCol=0; rc==SQLITE_OK && iCol<p->nColumn; iCol++){
        if( p->abNotindexed[iCol]==0 ){
          const char *zText = (const char *)sqlite3_column_text(pStmt, iCol+1);
          sqlite3_tokenizer_cursor *pT = 0;

          rc = sqlite3Fts3OpenTokenizer(p->pTokenizer, iLang, zText, -1, &pT);
          while( rc==SQLITE_OK ){
            char const *zToken;       /* Buffer containing token */
            int nToken = 0;           /* Number of bytes in token */
            int iDum1 = 0, iDum2 = 0; /* Dummy variables */
            int iPos = 0;             /* Position of token in zText */

            rc = pModule->xNext(pT, &zToken, &nToken, &iDum1, &iDum2, &iPos);
            if( rc==SQLITE_OK ){
              int i;
              cksum2 = cksum2 ^ fts3ChecksumEntry(
                  zToken, nToken, iLang, 0, iDocid, iCol, iPos
              );
              for(i=1; i<p->nIndex; i++){
                if( p->aIndex[i].nPrefix<=nToken ){
                  cksum2 = cksum2 ^ fts3ChecksumEntry(
                      zToken, p->aIndex[i].nPrefix, iLang, i, iDocid, iCol, iPos
                  );
                }
              }
            }
          }
          if( pT ) pModule->xClose(pT);
          if( rc==SQLITE_DONE ) rc = SQLITE_OK;
        }
      }
    }

    sqlite3_finalize(pStmt);
  }

  if( rc==SQLITE_CORRUPT_VTAB ){
    rc = SQLITE_OK;
    *pbOk = 0;
  }else{
    *pbOk = (rc==SQLITE_OK && cksum1==cksum2);
  }
  return rc;
}

/*
** Run the integrity-check. If no error occurs and the current contents of
** the FTS index are correct, return SQLITE_OK. Or, if the contents of the
** FTS index are incorrect, return SQLITE_CORRUPT_VTAB.
**
** Or, if an error (e.g. an OOM or IO error) occurs, return an SQLite
** error code.
**
** The integrity-check works as follows. For each token and indexed token
** prefix in the document set, a 64-bit checksum is calculated (by code
** in fts3ChecksumEntry()) based on the following:
**
**     + The index number (0 for the main index, 1 for the first prefix
**       index etc.),
**     + The token (or token prefix) text itself,
**     + The language-id of the row it appears in,
**     + The docid of the row it appears in,
**     + The column it appears in, and
**     + The tokens position within that column.

sqlite3.c  view on Meta::CPAN

      rc = SQLITE_OK;
    }
  }
#endif
  return rc;
}

#ifndef SQLITE_DISABLE_FTS4_DEFERRED
/*
** Delete all cached deferred doclists. Deferred doclists are cached
** (allocated) by the sqlite3Fts3CacheDeferredDoclists() function.
*/
SQLITE_PRIVATE void sqlite3Fts3FreeDeferredDoclists(Fts3Cursor *pCsr){
  Fts3DeferredToken *pDef;
  for(pDef=pCsr->pDeferred; pDef; pDef=pDef->pNext){
    fts3PendingListDelete(pDef->pList);
    pDef->pList = 0;
  }
}

/*
** Free all entries in the pCsr->pDeffered list. Entries are added to
** this list using sqlite3Fts3DeferToken().
*/
SQLITE_PRIVATE void sqlite3Fts3FreeDeferredTokens(Fts3Cursor *pCsr){
  Fts3DeferredToken *pDef;
  Fts3DeferredToken *pNext;
  for(pDef=pCsr->pDeferred; pDef; pDef=pNext){
    pNext = pDef->pNext;
    fts3PendingListDelete(pDef->pList);
    sqlite3_free(pDef);
  }
  pCsr->pDeferred = 0;
}

/*
** Generate deferred-doclists for all tokens in the pCsr->pDeferred list
** based on the row that pCsr currently points to.
**
** A deferred-doclist is like any other doclist with position information
** included, except that it only contains entries for a single row of the
** table, not for all rows.
*/
SQLITE_PRIVATE int sqlite3Fts3CacheDeferredDoclists(Fts3Cursor *pCsr){
  int rc = SQLITE_OK;             /* Return code */
  if( pCsr->pDeferred ){
    int i;                        /* Used to iterate through table columns */
    sqlite3_int64 iDocid;         /* Docid of the row pCsr points to */
    Fts3DeferredToken *pDef;      /* Used to iterate through deferred tokens */

    Fts3Table *p = (Fts3Table *)pCsr->base.pVtab;
    sqlite3_tokenizer *pT = p->pTokenizer;
    sqlite3_tokenizer_module const *pModule = pT->pModule;

    assert( pCsr->isRequireSeek==0 );
    iDocid = sqlite3_column_int64(pCsr->pStmt, 0);

    for(i=0; i<p->nColumn && rc==SQLITE_OK; i++){
      if( p->abNotindexed[i]==0 ){
        const char *zText = (const char *)sqlite3_column_text(pCsr->pStmt, i+1);
        sqlite3_tokenizer_cursor *pTC = 0;

        rc = sqlite3Fts3OpenTokenizer(pT, pCsr->iLangid, zText, -1, &pTC);
        while( rc==SQLITE_OK ){
          char const *zToken;       /* Buffer containing token */
          int nToken = 0;           /* Number of bytes in token */
          int iDum1 = 0, iDum2 = 0; /* Dummy variables */
          int iPos = 0;             /* Position of token in zText */

          rc = pModule->xNext(pTC, &zToken, &nToken, &iDum1, &iDum2, &iPos);
          for(pDef=pCsr->pDeferred; pDef && rc==SQLITE_OK; pDef=pDef->pNext){
            Fts3PhraseToken *pPT = pDef->pToken;
            if( (pDef->iCol>=p->nColumn || pDef->iCol==i)
                && (pPT->bFirst==0 || iPos==0)
                && (pPT->n==nToken || (pPT->isPrefix && pPT->n<nToken))
                && (0==memcmp(zToken, pPT->z, pPT->n))
              ){
              fts3PendingListAppend(&pDef->pList, iDocid, i, iPos, &rc);
            }
          }
        }
        if( pTC ) pModule->xClose(pTC);
        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
      }
    }

    for(pDef=pCsr->pDeferred; pDef && rc==SQLITE_OK; pDef=pDef->pNext){
      if( pDef->pList ){
        rc = fts3PendingListAppendVarint(&pDef->pList, 0);
      }
    }
  }

  return rc;
}

SQLITE_PRIVATE int sqlite3Fts3DeferredTokenList(
  Fts3DeferredToken *p,
  char **ppData,
  int *pnData
){
  char *pRet;
  int nSkip;
  sqlite3_int64 dummy;

  *ppData = 0;
  *pnData = 0;

  if( p->pList==0 ){
    return SQLITE_OK;
  }

  pRet = (char *)sqlite3_malloc64(p->pList->nData);
  if( !pRet ) return SQLITE_NOMEM;

  nSkip = sqlite3Fts3GetVarint(p->pList->aData, &dummy);
  *pnData = p->pList->nData - nSkip;
  *ppData = pRet;

  memcpy(pRet, &p->pList->aData[nSkip], *pnData);
  return SQLITE_OK;
}

/*
** Add an entry for token pToken to the pCsr->pDeferred list.
*/
SQLITE_PRIVATE int sqlite3Fts3DeferToken(
  Fts3Cursor *pCsr,               /* Fts3 table cursor */
  Fts3PhraseToken *pToken,        /* Token to defer */
  int iCol                        /* Column that token must appear in (or -1) */
){
  Fts3DeferredToken *pDeferred;
  pDeferred = sqlite3_malloc64(sizeof(*pDeferred));
  if( !pDeferred ){
    return SQLITE_NOMEM;
  }
  memset(pDeferred, 0, sizeof(*pDeferred));
  pDeferred->pToken = pToken;
  pDeferred->pNext = pCsr->pDeferred;
  pDeferred->iCol = iCol;
  pCsr->pDeferred = pDeferred;

  assert( pToken->pDeferred==0 );
  pToken->pDeferred = pDeferred;

  return SQLITE_OK;
}
#endif

/*
** SQLite value pRowid contains the rowid of a row that may or may not be
** present in the FTS3 table. If it is, delete it and adjust the contents
** of subsidiary data structures accordingly.
*/
static int fts3DeleteByRowid(
  Fts3Table *p,
  sqlite3_value *pRowid,
  int *pnChng,                    /* IN/OUT: Decrement if row is deleted */
  u32 *aSzDel
){
  int rc = SQLITE_OK;             /* Return code */
  int bFound = 0;                 /* True if *pRowid really is in the table */

  fts3DeleteTerms(&rc, p, pRowid, aSzDel, &bFound);
  if( bFound && rc==SQLITE_OK ){
    int isEmpty = 0;              /* Deleting *pRowid leaves the table empty */
    rc = fts3IsEmpty(p, pRowid, &isEmpty);
    if( rc==SQLITE_OK ){
      if( isEmpty ){
        /* Deleting this row means the whole table is empty. In this case
        ** delete the contents of all three tables and throw away any
        ** data in the pendingTerms hash table.  */
        rc = fts3DeleteAll(p, 1);
        *pnChng = 0;
        memset(aSzDel, 0, sizeof(u32) * (p->nColumn+1) * 2);
      }else{
        *pnChng = *pnChng - 1;
        if( p->zContentTbl==0 ){
          fts3SqlExec(&rc, p, SQL_DELETE_CONTENT, &pRowid);
        }
        if( p->bHasDocsize ){
          fts3SqlExec(&rc, p, SQL_DELETE_DOCSIZE, &pRowid);
        }
      }
    }
  }

  return rc;

sqlite3.c  view on Meta::CPAN

static int fts3ExprIterate2(
  Fts3Expr *pExpr,                /* Expression to iterate phrases of */
  int *piPhrase,                  /* Pointer to phrase counter */
  int (*x)(Fts3Expr*,int,void*),  /* Callback function to invoke for phrases */
  void *pCtx                      /* Second argument to pass to callback */
){
  int rc;                         /* Return code */
  int eType = pExpr->eType;     /* Type of expression node pExpr */

  if( eType!=FTSQUERY_PHRASE ){
    assert( pExpr->pLeft && pExpr->pRight );
    rc = fts3ExprIterate2(pExpr->pLeft, piPhrase, x, pCtx);
    if( rc==SQLITE_OK && eType!=FTSQUERY_NOT ){
      rc = fts3ExprIterate2(pExpr->pRight, piPhrase, x, pCtx);
    }
  }else{
    rc = x(pExpr, *piPhrase, pCtx);
    (*piPhrase)++;
  }
  return rc;
}

/*
** Iterate through all phrase nodes in an FTS3 query, except those that
** are part of a sub-tree that is the right-hand-side of a NOT operator.
** For each phrase node found, the supplied callback function is invoked.
**
** If the callback function returns anything other than SQLITE_OK,
** the iteration is abandoned and the error code returned immediately.
** Otherwise, SQLITE_OK is returned after a callback has been made for
** all eligible phrase nodes.
*/
SQLITE_PRIVATE int sqlite3Fts3ExprIterate(
  Fts3Expr *pExpr,                /* Expression to iterate phrases of */
  int (*x)(Fts3Expr*,int,void*),  /* Callback function to invoke for phrases */
  void *pCtx                      /* Second argument to pass to callback */
){
  int iPhrase = 0;                /* Variable used as the phrase counter */
  return fts3ExprIterate2(pExpr, &iPhrase, x, pCtx);
}

/*
** This is an sqlite3Fts3ExprIterate() callback used while loading the
** doclists for each phrase into Fts3Expr.aDoclist[]/nDoclist. See also
** fts3ExprLoadDoclists().
*/
static int fts3ExprLoadDoclistsCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
  int rc = SQLITE_OK;
  Fts3Phrase *pPhrase = pExpr->pPhrase;
  LoadDoclistCtx *p = (LoadDoclistCtx *)ctx;

  UNUSED_PARAMETER(iPhrase);

  p->nPhrase++;
  p->nToken += pPhrase->nToken;

  return rc;
}

/*
** Load the doclists for each phrase in the query associated with FTS3 cursor
** pCsr.
**
** If pnPhrase is not NULL, then *pnPhrase is set to the number of matchable
** phrases in the expression (all phrases except those directly or
** indirectly descended from the right-hand-side of a NOT operator). If
** pnToken is not NULL, then it is set to the number of tokens in all
** matchable phrases of the expression.
*/
static int fts3ExprLoadDoclists(
  Fts3Cursor *pCsr,               /* Fts3 cursor for current query */
  int *pnPhrase,                  /* OUT: Number of phrases in query */
  int *pnToken                    /* OUT: Number of tokens in query */
){
  int rc;                         /* Return Code */
  LoadDoclistCtx sCtx = {0,0,0};  /* Context for sqlite3Fts3ExprIterate() */
  sCtx.pCsr = pCsr;
  rc = sqlite3Fts3ExprIterate(pCsr->pExpr,fts3ExprLoadDoclistsCb,(void*)&sCtx);
  if( pnPhrase ) *pnPhrase = sCtx.nPhrase;
  if( pnToken ) *pnToken = sCtx.nToken;
  return rc;
}

static int fts3ExprPhraseCountCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
  (*(int *)ctx)++;
  pExpr->iPhrase = iPhrase;
  return SQLITE_OK;
}
static int fts3ExprPhraseCount(Fts3Expr *pExpr){
  int nPhrase = 0;
  (void)sqlite3Fts3ExprIterate(pExpr, fts3ExprPhraseCountCb, (void *)&nPhrase);
  return nPhrase;
}

/*
** Advance the position list iterator specified by the first two
** arguments so that it points to the first element with a value greater
** than or equal to parameter iNext.
*/
static void fts3SnippetAdvance(char **ppIter, i64 *piIter, int iNext){
  char *pIter = *ppIter;
  if( pIter ){
    i64 iIter = *piIter;

    while( iIter<iNext ){
      if( 0==(*pIter & 0xFE) ){
        iIter = -1;
        pIter = 0;
        break;
      }
      fts3GetDeltaPosition(&pIter, &iIter);
    }

    *piIter = iIter;
    *ppIter = pIter;
  }
}

/*
** Advance the snippet iterator to the next candidate snippet.
*/
static int fts3SnippetNextCandidate(SnippetIter *pIter){
  int i;                          /* Loop counter */

  if( pIter->iCurrent<0 ){
    /* The SnippetIter object has just been initialized. The first snippet
    ** candidate always starts at offset 0 (even if this candidate has a
    ** score of 0.0).
    */
    pIter->iCurrent = 0;

sqlite3.c  view on Meta::CPAN

  memcpy(&pStr->z[pStr->n], zAppend, nAppend);
  pStr->n += nAppend;
  pStr->z[pStr->n] = '\0';

  return SQLITE_OK;
}

/*
** The fts3BestSnippet() function often selects snippets that end with a
** query term. That is, the final term of the snippet is always a term
** that requires highlighting. For example, if 'X' is a highlighted term
** and '.' is a non-highlighted term, BestSnippet() may select:
**
**     ........X.....X
**
** This function "shifts" the beginning of the snippet forward in the
** document so that there are approximately the same number of
** non-highlighted terms to the right of the final highlighted term as there
** are to the left of the first highlighted term. For example, to this:
**
**     ....X.....X....
**
** This is done as part of extracting the snippet text, not when selecting
** the snippet. Snippet selection is done based on doclists only, so there
** is no way for fts3BestSnippet() to know whether or not the document
** actually contains terms that follow the final highlighted term.
*/
static int fts3SnippetShift(
  Fts3Table *pTab,                /* FTS3 table snippet comes from */
  int iLangid,                    /* Language id to use in tokenizing */
  int nSnippet,                   /* Number of tokens desired for snippet */
  const char *zDoc,               /* Document text to extract snippet from */
  int nDoc,                       /* Size of buffer zDoc in bytes */
  int *piPos,                     /* IN/OUT: First token of snippet */
  u64 *pHlmask                    /* IN/OUT: Mask of tokens to highlight */
){
  u64 hlmask = *pHlmask;          /* Local copy of initial highlight-mask */

  if( hlmask ){
    int nLeft;                    /* Tokens to the left of first highlight */
    int nRight;                   /* Tokens to the right of last highlight */
    int nDesired;                 /* Ideal number of tokens to shift forward */

    for(nLeft=0; !(hlmask & ((u64)1 << nLeft)); nLeft++);
    for(nRight=0; !(hlmask & ((u64)1 << (nSnippet-1-nRight))); nRight++);
    assert( (nSnippet-1-nRight)<=63 && (nSnippet-1-nRight)>=0 );
    nDesired = (nLeft-nRight)/2;

    /* Ideally, the start of the snippet should be pushed forward in the
    ** document nDesired tokens. This block checks if there are actually
    ** nDesired tokens to the right of the snippet. If so, *piPos and
    ** *pHlMask are updated to shift the snippet nDesired tokens to the
    ** right. Otherwise, the snippet is shifted by the number of tokens
    ** available.
    */
    if( nDesired>0 ){
      int nShift;                 /* Number of tokens to shift snippet by */
      int iCurrent = 0;           /* Token counter */
      int rc;                     /* Return Code */
      sqlite3_tokenizer_module *pMod;
      sqlite3_tokenizer_cursor *pC;
      pMod = (sqlite3_tokenizer_module *)pTab->pTokenizer->pModule;

      /* Open a cursor on zDoc/nDoc. Check if there are (nSnippet+nDesired)
      ** or more tokens in zDoc/nDoc.
      */
      rc = sqlite3Fts3OpenTokenizer(pTab->pTokenizer, iLangid, zDoc, nDoc, &pC);
      if( rc!=SQLITE_OK ){
        return rc;
      }
      while( rc==SQLITE_OK && iCurrent<(nSnippet+nDesired) ){
        const char *ZDUMMY; int DUMMY1 = 0, DUMMY2 = 0, DUMMY3 = 0;
        rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &DUMMY2, &DUMMY3, &iCurrent);
      }
      pMod->xClose(pC);
      if( rc!=SQLITE_OK && rc!=SQLITE_DONE ){ return rc; }

      nShift = (rc==SQLITE_DONE)+iCurrent-nSnippet;
      assert( nShift<=nDesired );
      if( nShift>0 ){
        *piPos += nShift;
        *pHlmask = hlmask >> nShift;
      }
    }
  }
  return SQLITE_OK;
}

/*
** Extract the snippet text for fragment pFragment from cursor pCsr and
** append it to string buffer pOut.
*/
static int fts3SnippetText(
  Fts3Cursor *pCsr,               /* FTS3 Cursor */
  SnippetFragment *pFragment,     /* Snippet to extract */
  int iFragment,                  /* Fragment number */
  int isLast,                     /* True for final fragment in snippet */
  int nSnippet,                   /* Number of tokens in extracted snippet */
  const char *zOpen,              /* String inserted before highlighted term */
  const char *zClose,             /* String inserted after highlighted term */
  const char *zEllipsis,          /* String inserted between snippets */
  StrBuffer *pOut                 /* Write output here */
){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  int rc;                         /* Return code */
  const char *zDoc;               /* Document text to extract snippet from */
  int nDoc;                       /* Size of zDoc in bytes */
  int iCurrent = 0;               /* Current token number of document */
  int iEnd = 0;                   /* Byte offset of end of current token */
  int isShiftDone = 0;            /* True after snippet is shifted */
  int iPos = pFragment->iPos;     /* First token of snippet */
  u64 hlmask = pFragment->hlmask; /* Highlight-mask for snippet */
  int iCol = pFragment->iCol+1;   /* Query column to extract text from */
  sqlite3_tokenizer_module *pMod; /* Tokenizer module methods object */
  sqlite3_tokenizer_cursor *pC;   /* Tokenizer cursor open on zDoc/nDoc */

  zDoc = (const char *)sqlite3_column_text(pCsr->pStmt, iCol);
  if( zDoc==0 ){
    if( sqlite3_column_type(pCsr->pStmt, iCol)!=SQLITE_NULL ){
      return SQLITE_NOMEM;
    }
    return SQLITE_OK;
  }
  nDoc = sqlite3_column_bytes(pCsr->pStmt, iCol);

  /* Open a token cursor on the document. */
  pMod = (sqlite3_tokenizer_module *)pTab->pTokenizer->pModule;
  rc = sqlite3Fts3OpenTokenizer(pTab->pTokenizer, pCsr->iLangid, zDoc,nDoc,&pC);
  if( rc!=SQLITE_OK ){
    return rc;
  }

  while( rc==SQLITE_OK ){
    const char *ZDUMMY;           /* Dummy argument used with tokenizer */
    int DUMMY1 = -1;              /* Dummy argument used with tokenizer */
    int iBegin = 0;               /* Offset in zDoc of start of token */
    int iFin = 0;                 /* Offset in zDoc of end of token */
    int isHighlight = 0;          /* True for highlighted terms */

    /* Variable DUMMY1 is initialized to a negative value above. Elsewhere
    ** in the FTS code the variable that the third argument to xNext points to
    ** is initialized to zero before the first (*but not necessarily
    ** subsequent*) call to xNext(). This is done for a particular application
    ** that needs to know whether or not the tokenizer is being used for
    ** snippet generation or for some other purpose.
    **
    ** Extreme care is required when writing code to depend on this
    ** initialization. It is not a documented part of the tokenizer interface.
    ** If a tokenizer is used directly by any code outside of FTS, this
    ** convention might not be respected.  */
    rc = pMod->xNext(pC, &ZDUMMY, &DUMMY1, &iBegin, &iFin, &iCurrent);
    if( rc!=SQLITE_OK ){
      if( rc==SQLITE_DONE ){
        /* Special case - the last token of the snippet is also the last token
        ** of the column. Append any punctuation that occurred between the end
        ** of the previous token and the end of the document to the output.
        ** Then break out of the loop. */
        rc = fts3StringAppend(pOut, &zDoc[iEnd], -1);
      }
      break;
    }
    if( iCurrent<iPos ){ continue; }

    if( !isShiftDone ){
      int n = nDoc - iBegin;
      rc = fts3SnippetShift(
          pTab, pCsr->iLangid, nSnippet, &zDoc[iBegin], n, &iPos, &hlmask
      );
      isShiftDone = 1;

      /* Now that the shift has been done, check if the initial "..." are
      ** required. They are required if (a) this is not the first fragment,
      ** or (b) this fragment does not begin at position 0 of its column.
      */
      if( rc==SQLITE_OK ){
        if( iPos>0 || iFragment>0 ){
          rc = fts3StringAppend(pOut, zEllipsis, -1);
        }else if( iBegin ){
          rc = fts3StringAppend(pOut, zDoc, iBegin);
        }
      }
      if( rc!=SQLITE_OK || iCurrent<iPos ) continue;
    }

    if( iCurrent>=(iPos+nSnippet) ){
      if( isLast ){

sqlite3.c  view on Meta::CPAN

        pIt->iPos = pIt->iPosOffset;
        fts3LcsIteratorAdvance(pIt);
        if( pIt->pRead==0 ){
          rc = FTS_CORRUPT_VTAB;
          goto matchinfo_lcs_out;
        }
        nLive++;
      }
    }

    while( nLive>0 ){
      LcsIterator *pAdv = 0;      /* The iterator to advance by one position */
      int nThisLcs = 0;           /* LCS for the current iterator positions */

      for(i=0; i<pInfo->nPhrase; i++){
        LcsIterator *pIter = &aIter[i];
        if( pIter->pRead==0 ){
          /* This iterator is already at EOF for this column. */
          nThisLcs = 0;
        }else{
          if( pAdv==0 || pIter->iPos<pAdv->iPos ){
            pAdv = pIter;
          }
          if( nThisLcs==0 || pIter->iPos==pIter[-1].iPos ){
            nThisLcs++;
          }else{
            nThisLcs = 1;
          }
          if( nThisLcs>nLcs ) nLcs = nThisLcs;
        }
      }
      if( fts3LcsIteratorAdvance(pAdv) ) nLive--;
    }

    pInfo->aMatchinfo[iCol] = nLcs;
  }

 matchinfo_lcs_out:
  sqlite3_free(aIter);
  return rc;
}

/*
** Populate the buffer pInfo->aMatchinfo[] with an array of integers to
** be returned by the matchinfo() function. Argument zArg contains the
** format string passed as the second argument to matchinfo (or the
** default value "pcx" if no second argument was specified). The format
** string has already been validated and the pInfo->aMatchinfo[] array
** is guaranteed to be large enough for the output.
**
** If bGlobal is true, then populate all fields of the matchinfo() output.
** If it is false, then assume that those fields that do not change between
** rows (i.e. FTS3_MATCHINFO_NPHRASE, NCOL, NDOC, AVGLENGTH and part of HITS)
** have already been populated.
**
** Return SQLITE_OK if successful, or an SQLite error code if an error
** occurs. If a value other than SQLITE_OK is returned, the state the
** pInfo->aMatchinfo[] buffer is left in is undefined.
*/
static int fts3MatchinfoValues(
  Fts3Cursor *pCsr,               /* FTS3 cursor object */
  int bGlobal,                    /* True to grab the global stats */
  MatchInfo *pInfo,               /* Matchinfo context object */
  const char *zArg                /* Matchinfo format string */
){
  int rc = SQLITE_OK;
  int i;
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  sqlite3_stmt *pSelect = 0;

  for(i=0; rc==SQLITE_OK && zArg[i]; i++){
    pInfo->flag = zArg[i];
    switch( zArg[i] ){
      case FTS3_MATCHINFO_NPHRASE:
        if( bGlobal ) pInfo->aMatchinfo[0] = pInfo->nPhrase;
        break;

      case FTS3_MATCHINFO_NCOL:
        if( bGlobal ) pInfo->aMatchinfo[0] = pInfo->nCol;
        break;

      case FTS3_MATCHINFO_NDOC:
        if( bGlobal ){
          sqlite3_int64 nDoc = 0;
          rc = fts3MatchinfoSelectDoctotal(pTab, &pSelect, &nDoc, 0, 0);
          pInfo->aMatchinfo[0] = (u32)nDoc;
        }
        break;

      case FTS3_MATCHINFO_AVGLENGTH:
        if( bGlobal ){
          sqlite3_int64 nDoc;     /* Number of rows in table */
          const char *a;          /* Aggregate column length array */
          const char *pEnd;       /* First byte past end of length array */

          rc = fts3MatchinfoSelectDoctotal(pTab, &pSelect, &nDoc, &a, &pEnd);
          if( rc==SQLITE_OK ){
            int iCol;
            for(iCol=0; iCol<pInfo->nCol; iCol++){
              u32 iVal;
              sqlite3_int64 nToken;
              a += sqlite3Fts3GetVarint(a, &nToken);
              if( a>pEnd ){
                rc = SQLITE_CORRUPT_VTAB;
                break;
              }
              iVal = (u32)(((u32)(nToken&0xffffffff)+nDoc/2)/nDoc);
              pInfo->aMatchinfo[iCol] = iVal;
            }
          }
        }
        break;

      case FTS3_MATCHINFO_LENGTH: {
        sqlite3_stmt *pSelectDocsize = 0;
        rc = sqlite3Fts3SelectDocsize(pTab, pCsr->iPrevId, &pSelectDocsize);
        if( rc==SQLITE_OK ){
          int iCol;
          const char *a = sqlite3_column_blob(pSelectDocsize, 0);
          const char *pEnd = a + sqlite3_column_bytes(pSelectDocsize, 0);
          for(iCol=0; iCol<pInfo->nCol; iCol++){

sqlite3.c  view on Meta::CPAN

** restart it as a regular, non-incremental query. Return SQLITE_OK
** if successful, or an SQLite error code otherwise.
*/
static int fts3ExprRestartIfCb(Fts3Expr *pExpr, int iPhrase, void *ctx){
  TermOffsetCtx *p = (TermOffsetCtx*)ctx;
  int rc = SQLITE_OK;
  UNUSED_PARAMETER(iPhrase);
  if( pExpr->pPhrase && pExpr->pPhrase->bIncr ){
    rc = sqlite3Fts3MsrCancel(p->pCsr, pExpr);
    pExpr->pPhrase->bIncr = 0;
  }
  return rc;
}

/*
** Implementation of offsets() function.
*/
SQLITE_PRIVATE void sqlite3Fts3Offsets(
  sqlite3_context *pCtx,          /* SQLite function call context */
  Fts3Cursor *pCsr                /* Cursor object */
){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  sqlite3_tokenizer_module const *pMod = pTab->pTokenizer->pModule;
  int rc;                         /* Return Code */
  int nToken;                     /* Number of tokens in query */
  int iCol;                       /* Column currently being processed */
  StrBuffer res = {0, 0, 0};      /* Result string */
  TermOffsetCtx sCtx;             /* Context for fts3ExprTermOffsetInit() */

  if( !pCsr->pExpr ){
    sqlite3_result_text(pCtx, "", 0, SQLITE_STATIC);
    return;
  }

  memset(&sCtx, 0, sizeof(sCtx));
  assert( pCsr->isRequireSeek==0 );

  /* Count the number of terms in the query */
  rc = fts3ExprLoadDoclists(pCsr, 0, &nToken);
  if( rc!=SQLITE_OK ) goto offsets_out;

  /* Allocate the array of TermOffset iterators. */
  sCtx.aTerm = (TermOffset *)sqlite3Fts3MallocZero(sizeof(TermOffset)*nToken);
  if( 0==sCtx.aTerm ){
    rc = SQLITE_NOMEM;
    goto offsets_out;
  }
  sCtx.iDocid = pCsr->iPrevId;
  sCtx.pCsr = pCsr;

  /* If a query restart will be required, do it here, rather than later of
  ** after pointers to poslist buffers that may be invalidated by a restart
  ** have been saved.  */
  rc = sqlite3Fts3ExprIterate(pCsr->pExpr, fts3ExprRestartIfCb, (void*)&sCtx);
  if( rc!=SQLITE_OK ) goto offsets_out;

  /* Loop through the table columns, appending offset information to
  ** string-buffer res for each column.
  */
  for(iCol=0; iCol<pTab->nColumn; iCol++){
    sqlite3_tokenizer_cursor *pC; /* Tokenizer cursor */
    const char *ZDUMMY;           /* Dummy argument used with xNext() */
    int NDUMMY = 0;               /* Dummy argument used with xNext() */
    int iStart = 0;
    int iEnd = 0;
    int iCurrent = 0;
    const char *zDoc;
    int nDoc;

    /* Initialize the contents of sCtx.aTerm[] for column iCol. This
    ** operation may fail if the database contains corrupt records.
    */
    sCtx.iCol = iCol;
    sCtx.iTerm = 0;
    rc = sqlite3Fts3ExprIterate(
        pCsr->pExpr, fts3ExprTermOffsetInit, (void*)&sCtx
    );
    if( rc!=SQLITE_OK ) goto offsets_out;

    /* Retreive the text stored in column iCol. If an SQL NULL is stored
    ** in column iCol, jump immediately to the next iteration of the loop.
    ** If an OOM occurs while retrieving the data (this can happen if SQLite
    ** needs to transform the data from utf-16 to utf-8), return SQLITE_NOMEM
    ** to the caller.
    */
    zDoc = (const char *)sqlite3_column_text(pCsr->pStmt, iCol+1);
    nDoc = sqlite3_column_bytes(pCsr->pStmt, iCol+1);
    if( zDoc==0 ){
      if( sqlite3_column_type(pCsr->pStmt, iCol+1)==SQLITE_NULL ){
        continue;
      }
      rc = SQLITE_NOMEM;
      goto offsets_out;
    }

    /* Initialize a tokenizer iterator to iterate through column iCol. */
    rc = sqlite3Fts3OpenTokenizer(pTab->pTokenizer, pCsr->iLangid,
        zDoc, nDoc, &pC
    );
    if( rc!=SQLITE_OK ) goto offsets_out;

    rc = pMod->xNext(pC, &ZDUMMY, &NDUMMY, &iStart, &iEnd, &iCurrent);
    while( rc==SQLITE_OK ){
      int i;                      /* Used to loop through terms */
      int iMinPos = 0x7FFFFFFF;   /* Position of next token */
      TermOffset *pTerm = 0;      /* TermOffset associated with next token */

      for(i=0; i<nToken; i++){
        TermOffset *pT = &sCtx.aTerm[i];
        if( pT->pList && (pT->iPos-pT->iOff)<iMinPos ){
          iMinPos = pT->iPos-pT->iOff;
          pTerm = pT;
        }
      }

      if( !pTerm ){
        /* All offsets for this column have been gathered. */
        rc = SQLITE_DONE;
      }else{
        assert_fts3_nc( iCurrent<=iMinPos );
        if( 0==(0xFE&*pTerm->pList) ){
          pTerm->pList = 0;
        }else{
          fts3GetDeltaPosition(&pTerm->pList, &pTerm->iPos);
        }
        while( rc==SQLITE_OK && iCurrent<iMinPos ){
          rc = pMod->xNext(pC, &ZDUMMY, &NDUMMY, &iStart, &iEnd, &iCurrent);
        }
        if( rc==SQLITE_OK ){
          char aBuffer[64];
          sqlite3_snprintf(sizeof(aBuffer), aBuffer,
              "%d %d %d %d ", iCol, pTerm-sCtx.aTerm, iStart, iEnd-iStart
          );
          rc = fts3StringAppend(&res, aBuffer, -1);
        }else if( rc==SQLITE_DONE && pTab->zContentTbl==0 ){
          rc = FTS_CORRUPT_VTAB;
        }
      }
    }
    if( rc==SQLITE_DONE ){
      rc = SQLITE_OK;
    }

    pMod->xClose(pC);
    if( rc!=SQLITE_OK ) goto offsets_out;
  }

 offsets_out:
  sqlite3_free(sCtx.aTerm);
  assert( rc!=SQLITE_DONE );
  sqlite3Fts3SegmentsClose(pTab);
  if( rc!=SQLITE_OK ){
    sqlite3_result_error_code(pCtx,  rc);
    sqlite3_free(res.z);
  }else{
    sqlite3_result_text(pCtx, res.z, res.n-1, sqlite3_free);
  }
  return;
}

/*
** Implementation of matchinfo() function.
*/
SQLITE_PRIVATE void sqlite3Fts3Matchinfo(
  sqlite3_context *pContext,      /* Function call context */
  Fts3Cursor *pCsr,               /* FTS3 table cursor */
  const char *zArg                /* Second arg to matchinfo() function */
){
  Fts3Table *pTab = (Fts3Table *)pCsr->base.pVtab;
  const char *zFormat;

  if( zArg ){
    zFormat = zArg;
  }else{
    zFormat = FTS3_MATCHINFO_DEFAULT;
  }

  if( !pCsr->pExpr ){
    sqlite3_result_blob(pContext, "", 0, SQLITE_STATIC);
    return;
  }else{
    /* Retrieve matchinfo() data. */
    fts3GetMatchinfo(pContext, pCsr, zFormat);
    sqlite3Fts3SegmentsClose(pTab);
  }
}

#endif

/************** End of fts3_snippet.c ****************************************/
/************** Begin file fts3_unicode.c ************************************/
/*
** 2012 May 24
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** Implementation of the "unicode" full-text-search tokenizer.
*/

#ifndef SQLITE_DISABLE_FTS3_UNICODE

/* #include "fts3Int.h" */
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)

/* #include <assert.h> */
/* #include <stdlib.h> */
/* #include <stdio.h> */
/* #include <string.h> */

/* #include "fts3_tokenizer.h" */

/*
** The following two macros - READ_UTF8 and WRITE_UTF8 - have been copied
** from the sqlite3 source file utf.c. If this file is compiled as part
** of the amalgamation, they are not required.
*/
#ifndef SQLITE_AMALGAMATION

static const unsigned char sqlite3Utf8Trans1[] = {
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
  0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
  0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
  0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
  0x00, 0x01, 0x02, 0x03, 0x00, 0x01, 0x00, 0x00,
};

#define READ_UTF8(zIn, zTerm, c)                           \
  c = *(zIn++);                                            \
  if( c>=0xc0 ){                                           \
    c = sqlite3Utf8Trans1[c-0xc0];                         \
    while( zIn!=zTerm && (*zIn & 0xc0)==0x80 ){            \
      c = (c<<6) + (0x3f & *(zIn++));                      \
    }                                                      \
    if( c<0x80                                             \
        || (c&0xFFFFF800)==0xD800                          \
        || (c&0xFFFFFFFE)==0xFFFE ){  c = 0xFFFD; }        \
  }

#define WRITE_UTF8(zOut, c) {                          \
  if( c<0x00080 ){                                     \
    *zOut++ = (u8)(c&0xFF);                            \
  }                                                    \
  else if( c<0x00800 ){                                \
    *zOut++ = 0xC0 + (u8)((c>>6)&0x1F);                \
    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
  }                                                    \
  else if( c<0x10000 ){                                \
    *zOut++ = 0xE0 + (u8)((c>>12)&0x0F);               \
    *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);              \
    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
  }else{                                               \
    *zOut++ = 0xF0 + (u8)((c>>18) & 0x07);             \
    *zOut++ = 0x80 + (u8)((c>>12) & 0x3F);             \
    *zOut++ = 0x80 + (u8)((c>>6) & 0x3F);              \
    *zOut++ = 0x80 + (u8)(c & 0x3F);                   \
  }                                                    \
}

#endif /* ifndef SQLITE_AMALGAMATION */

typedef struct unicode_tokenizer unicode_tokenizer;
typedef struct unicode_cursor unicode_cursor;

struct unicode_tokenizer {
  sqlite3_tokenizer base;
  int eRemoveDiacritic;
  int nException;
  int *aiException;
};

struct unicode_cursor {
  sqlite3_tokenizer_cursor base;
  const unsigned char *aInput;    /* Input text being tokenized */
  int nInput;                     /* Size of aInput[] in bytes */
  int iOff;                       /* Current offset within aInput[] */
  int iToken;                     /* Index of next token to be returned */
  char *zToken;                   /* storage for current token */
  int nAlloc;                     /* space allocated at zToken */
};


/*
** Destroy a tokenizer allocated by unicodeCreate().
*/
static int unicodeDestroy(sqlite3_tokenizer *pTokenizer){
  if( pTokenizer ){
    unicode_tokenizer *p = (unicode_tokenizer *)pTokenizer;
    sqlite3_free(p->aiException);
    sqlite3_free(p);
  }
  return SQLITE_OK;
}

/*
** As part of a tokenchars= or separators= option, the CREATE VIRTUAL TABLE
** statement has specified that the tokenizer for this table shall consider
** all characters in string zIn/nIn to be separators (if bAlnum==0) or
** token characters (if bAlnum==1).
**
** For each codepoint in the zIn/nIn string, this function checks if the
** sqlite3FtsUnicodeIsalnum() function already returns the desired result.
** If so, no action is taken. Otherwise, the codepoint is added to the
** unicode_tokenizer.aiException[] array. For the purposes of tokenization,
** the return value of sqlite3FtsUnicodeIsalnum() is inverted for all
** codepoints in the aiException[] array.
**
** If a standalone diacritic mark (one that sqlite3FtsUnicodeIsdiacritic()
** identifies as a diacritic) occurs in the zIn/nIn string it is ignored.
** It is not possible to change the behavior of the tokenizer with respect
** to these codepoints.
*/
static int unicodeAddExceptions(
  unicode_tokenizer *p,           /* Tokenizer to add exceptions to */
  int bAlnum,                     /* Replace Isalnum() return value with this */
  const char *zIn,                /* Array of characters to make exceptions */
  int nIn                         /* Length of z in bytes */
){
  const unsigned char *z = (const unsigned char *)zIn;
  const unsigned char *zTerm = &z[nIn];
  unsigned int iCode;
  int nEntry = 0;

  assert( bAlnum==0 || bAlnum==1 );

  while( z<zTerm ){
    READ_UTF8(z, zTerm, iCode);
    assert( (sqlite3FtsUnicodeIsalnum((int)iCode) & 0xFFFFFFFE)==0 );
    if( sqlite3FtsUnicodeIsalnum((int)iCode)!=bAlnum
     && sqlite3FtsUnicodeIsdiacritic((int)iCode)==0
    ){
      nEntry++;
    }

sqlite3.c  view on Meta::CPAN

** Return true if, for the purposes of tokenization, codepoint iCode is
** considered a token character (not a separator).
*/
static int unicodeIsAlnum(unicode_tokenizer *p, int iCode){
  assert( (sqlite3FtsUnicodeIsalnum(iCode) & 0xFFFFFFFE)==0 );
  return sqlite3FtsUnicodeIsalnum(iCode) ^ unicodeIsException(p, iCode);
}

/*
** Create a new tokenizer instance.
*/
static int unicodeCreate(
  int nArg,                       /* Size of array argv[] */
  const char * const *azArg,      /* Tokenizer creation arguments */
  sqlite3_tokenizer **pp          /* OUT: New tokenizer handle */
){
  unicode_tokenizer *pNew;        /* New tokenizer object */
  int i;
  int rc = SQLITE_OK;

  pNew = (unicode_tokenizer *) sqlite3_malloc(sizeof(unicode_tokenizer));
  if( pNew==NULL ) return SQLITE_NOMEM;
  memset(pNew, 0, sizeof(unicode_tokenizer));
  pNew->eRemoveDiacritic = 1;

  for(i=0; rc==SQLITE_OK && i<nArg; i++){
    const char *z = azArg[i];
    int n = (int)strlen(z);

    if( n==19 && memcmp("remove_diacritics=1", z, 19)==0 ){
      pNew->eRemoveDiacritic = 1;
    }
    else if( n==19 && memcmp("remove_diacritics=0", z, 19)==0 ){
      pNew->eRemoveDiacritic = 0;
    }
    else if( n==19 && memcmp("remove_diacritics=2", z, 19)==0 ){
      pNew->eRemoveDiacritic = 2;
    }
    else if( n>=11 && memcmp("tokenchars=", z, 11)==0 ){
      rc = unicodeAddExceptions(pNew, 1, &z[11], n-11);
    }
    else if( n>=11 && memcmp("separators=", z, 11)==0 ){
      rc = unicodeAddExceptions(pNew, 0, &z[11], n-11);
    }
    else{
      /* Unrecognized argument */
      rc  = SQLITE_ERROR;
    }
  }

  if( rc!=SQLITE_OK ){
    unicodeDestroy((sqlite3_tokenizer *)pNew);
    pNew = 0;
  }
  *pp = (sqlite3_tokenizer *)pNew;
  return rc;
}

/*
** Prepare to begin tokenizing a particular string.  The input
** string to be tokenized is pInput[0..nBytes-1].  A cursor
** used to incrementally tokenize this string is returned in
** *ppCursor.
*/
static int unicodeOpen(
  sqlite3_tokenizer *p,           /* The tokenizer */
  const char *aInput,             /* Input string */
  int nInput,                     /* Size of string aInput in bytes */
  sqlite3_tokenizer_cursor **pp   /* OUT: New cursor object */
){
  unicode_cursor *pCsr;

  pCsr = (unicode_cursor *)sqlite3_malloc(sizeof(unicode_cursor));
  if( pCsr==0 ){
    return SQLITE_NOMEM;
  }
  memset(pCsr, 0, sizeof(unicode_cursor));

  pCsr->aInput = (const unsigned char *)aInput;
  if( aInput==0 ){
    pCsr->nInput = 0;
    pCsr->aInput = (const unsigned char*)"";
  }else if( nInput<0 ){
    pCsr->nInput = (int)strlen(aInput);
  }else{
    pCsr->nInput = nInput;
  }

  *pp = &pCsr->base;
  UNUSED_PARAMETER(p);
  return SQLITE_OK;
}

/*
** Close a tokenization cursor previously opened by a call to
** simpleOpen() above.
*/
static int unicodeClose(sqlite3_tokenizer_cursor *pCursor){
  unicode_cursor *pCsr = (unicode_cursor *) pCursor;
  sqlite3_free(pCsr->zToken);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

/*
** Extract the next token from a tokenization cursor.  The cursor must
** have been opened by a prior call to simpleOpen().
*/
static int unicodeNext(
  sqlite3_tokenizer_cursor *pC,   /* Cursor returned by simpleOpen */
  const char **paToken,           /* OUT: Token text */
  int *pnToken,                   /* OUT: Number of bytes at *paToken */
  int *piStart,                   /* OUT: Starting offset of token */
  int *piEnd,                     /* OUT: Ending offset of token */
  int *piPos                      /* OUT: Position integer of token */
){
  unicode_cursor *pCsr = (unicode_cursor *)pC;
  unicode_tokenizer *p = ((unicode_tokenizer *)pCsr->base.pTokenizer);
  unsigned int iCode = 0;
  char *zOut;
  const unsigned char *z = &pCsr->aInput[pCsr->iOff];
  const unsigned char *zStart = z;
  const unsigned char *zEnd;
  const unsigned char *zTerm = &pCsr->aInput[pCsr->nInput];

  /* Scan past any delimiter characters before the start of the next token.
  ** Return SQLITE_DONE early if this takes us all the way to the end of
  ** the input.  */
  while( z<zTerm ){
    READ_UTF8(z, zTerm, iCode);
    if( unicodeIsAlnum(p, (int)iCode) ) break;
    zStart = z;
  }
  if( zStart>=zTerm ) return SQLITE_DONE;

  zOut = pCsr->zToken;
  do {
    int iOut;

    /* Grow the output buffer if required. */
    if( (zOut-pCsr->zToken)>=(pCsr->nAlloc-4) ){
      char *zNew = sqlite3_realloc64(pCsr->zToken, pCsr->nAlloc+64);
      if( !zNew ) return SQLITE_NOMEM;
      zOut = &zNew[zOut - pCsr->zToken];
      pCsr->zToken = zNew;
      pCsr->nAlloc += 64;
    }

    /* Write the folded case of the last character read to the output */
    zEnd = z;
    iOut = sqlite3FtsUnicodeFold((int)iCode, p->eRemoveDiacritic);
    if( iOut ){
      WRITE_UTF8(zOut, iOut);
    }

    /* If the cursor is not at EOF, read the next character */
    if( z>=zTerm ) break;
    READ_UTF8(z, zTerm, iCode);
  }while( unicodeIsAlnum(p, (int)iCode)
       || sqlite3FtsUnicodeIsdiacritic((int)iCode)
  );

  /* Set the output variables and return. */
  pCsr->iOff = (int)(z - pCsr->aInput);
  *paToken = pCsr->zToken;
  *pnToken = (int)(zOut - pCsr->zToken);
  *piStart = (int)(zStart - pCsr->aInput);
  *piEnd = (int)(zEnd - pCsr->aInput);
  *piPos = pCsr->iToken++;
  return SQLITE_OK;
}

/*
** Set *ppModule to a pointer to the sqlite3_tokenizer_module
** structure for the unicode tokenizer.
*/
SQLITE_PRIVATE void sqlite3Fts3UnicodeTokenizer(sqlite3_tokenizer_module const **ppModule){
  static const sqlite3_tokenizer_module module = {
    0,
    unicodeCreate,
    unicodeDestroy,
    unicodeOpen,
    unicodeClose,
    unicodeNext,
    0,
  };
  *ppModule = &module;
}

#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
#endif /* ifndef SQLITE_DISABLE_FTS3_UNICODE */

/************** End of fts3_unicode.c ****************************************/
/************** Begin file fts3_unicode2.c ***********************************/
/*
** 2012-05-25
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
*/

/*
** DO NOT EDIT THIS MACHINE GENERATED FILE.
*/

#ifndef SQLITE_DISABLE_FTS3_UNICODE
#if defined(SQLITE_ENABLE_FTS3) || defined(SQLITE_ENABLE_FTS4)

/* #include <assert.h> */

sqlite3.c  view on Meta::CPAN

    }
  }
}
static void jsonObjectCompute(sqlite3_context *ctx, int isFinal){
  JsonString *pStr;
  pStr = (JsonString*)sqlite3_aggregate_context(ctx, 0);
  if( pStr ){
    int flags;
    jsonAppendChar(pStr, '}');
    pStr->pCtx = ctx;
    flags = SQLITE_PTR_TO_INT(sqlite3_user_data(ctx));
    if( pStr->eErr ){
      jsonReturnString(pStr, 0, 0);
      return;
    }else if( flags & JSON_BLOB ){
      jsonReturnStringAsBlob(pStr);
      if( isFinal ){
        if( !pStr->bStatic ) sqlite3RCStrUnref(pStr->zBuf);
      }else{
        jsonStringTrimOneChar(pStr);
      }
      return;
    }else if( isFinal ){
      sqlite3_result_text(ctx, pStr->zBuf, (int)pStr->nUsed,
                          pStr->bStatic ? SQLITE_TRANSIENT :
                          sqlite3RCStrUnref);
      pStr->bStatic = 1;
    }else{
      sqlite3_result_text(ctx, pStr->zBuf, (int)pStr->nUsed, SQLITE_TRANSIENT);
      jsonStringTrimOneChar(pStr);
    }
  }else{
    sqlite3_result_text(ctx, "{}", 2, SQLITE_STATIC);
  }
  sqlite3_result_subtype(ctx, JSON_SUBTYPE);
}
static void jsonObjectValue(sqlite3_context *ctx){
  jsonObjectCompute(ctx, 0);
}
static void jsonObjectFinal(sqlite3_context *ctx){
  jsonObjectCompute(ctx, 1);
}



#ifndef SQLITE_OMIT_VIRTUALTABLE
/****************************************************************************
** The json_each virtual table
****************************************************************************/
typedef struct JsonParent JsonParent;
struct JsonParent {
  u32 iHead;                 /* Start of object or array */
  u32 iValue;                /* Start of the value */
  u32 iEnd;                  /* First byte past the end */
  u32 nPath;                 /* Length of path */
  i64 iKey;                  /* Key for JSONB_ARRAY */
};

typedef struct JsonEachCursor JsonEachCursor;
struct JsonEachCursor {
  sqlite3_vtab_cursor base;  /* Base class - must be first */
  u32 iRowid;                /* The rowid */
  u32 i;                     /* Index in sParse.aBlob[] of current row */
  u32 iEnd;                  /* EOF when i equals or exceeds this value */
  u32 nRoot;                 /* Size of the root path in bytes */
  u8 eType;                  /* Type of the container for element i */
  u8 bRecursive;             /* True for json_tree().  False for json_each() */
  u8 eMode;                  /* 1 for json_each().  2 for jsonb_each() */
  u32 nParent;               /* Current nesting depth */
  u32 nParentAlloc;          /* Space allocated for aParent[] */
  JsonParent *aParent;       /* Parent elements of i */
  sqlite3 *db;               /* Database connection */
  JsonString path;           /* Current path */
  JsonParse sParse;          /* Parse of the input JSON */
};
typedef struct JsonEachConnection JsonEachConnection;
struct JsonEachConnection {
  sqlite3_vtab base;         /* Base class - must be first */
  sqlite3 *db;               /* Database connection */
  u8 eMode;                  /* 1 for json_each().  2 for jsonb_each() */
  u8 bRecursive;             /* True for json_tree().  False for json_each() */
};


/* Constructor for the json_each virtual table */
static int jsonEachConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  JsonEachConnection *pNew;
  int rc;

/* Column numbers */
#define JEACH_KEY     0
#define JEACH_VALUE   1
#define JEACH_TYPE    2
#define JEACH_ATOM    3
#define JEACH_ID      4
#define JEACH_PARENT  5
#define JEACH_FULLKEY 6
#define JEACH_PATH    7
/* The xBestIndex method assumes that the JSON and ROOT columns are
** the last two columns in the table.  Should this ever changes, be
** sure to update the xBestIndex method. */
#define JEACH_JSON    8
#define JEACH_ROOT    9

  UNUSED_PARAMETER(pzErr);
  UNUSED_PARAMETER(argv);
  UNUSED_PARAMETER(argc);
  UNUSED_PARAMETER(pAux);
  rc = sqlite3_declare_vtab(db,
     "CREATE TABLE x(key,value,type,atom,id,parent,fullkey,path,"
                    "json HIDDEN,root HIDDEN)");
  if( rc==SQLITE_OK ){
    pNew = (JsonEachConnection*)sqlite3DbMallocZero(db, sizeof(*pNew));
    *ppVtab = (sqlite3_vtab*)pNew;
    if( pNew==0 ) return SQLITE_NOMEM;
    sqlite3_vtab_config(db, SQLITE_VTAB_INNOCUOUS);
    pNew->db = db;
    pNew->eMode = argv[0][4]=='b' ? 2 : 1;
    pNew->bRecursive = argv[0][4+pNew->eMode]=='t';
  }
  return rc;
}

/* destructor for json_each virtual table */
static int jsonEachDisconnect(sqlite3_vtab *pVtab){
  JsonEachConnection *p = (JsonEachConnection*)pVtab;
  sqlite3DbFree(p->db, pVtab);
  return SQLITE_OK;
}

/* constructor for a JsonEachCursor object for json_each()/json_tree(). */
static int jsonEachOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
  JsonEachConnection *pVtab = (JsonEachConnection*)p;
  JsonEachCursor *pCur;

  UNUSED_PARAMETER(p);
  pCur = sqlite3DbMallocZero(pVtab->db, sizeof(*pCur));
  if( pCur==0 ) return SQLITE_NOMEM;
  pCur->db = pVtab->db;
  pCur->eMode = pVtab->eMode;
  pCur->bRecursive = pVtab->bRecursive;
  jsonStringZero(&pCur->path);
  *ppCursor = &pCur->base;
  return SQLITE_OK;
}

/* Reset a JsonEachCursor back to its original state.  Free any memory
** held. */
static void jsonEachCursorReset(JsonEachCursor *p){
  jsonParseReset(&p->sParse);
  jsonStringReset(&p->path);
  sqlite3DbFree(p->db, p->aParent);
  p->iRowid = 0;
  p->i = 0;
  p->aParent = 0;
  p->nParent = 0;
  p->nParentAlloc = 0;
  p->iEnd = 0;
  p->eType = 0;
}

/* Destructor for a jsonEachCursor object */
static int jsonEachClose(sqlite3_vtab_cursor *cur){
  JsonEachCursor *p = (JsonEachCursor*)cur;
  jsonEachCursorReset(p);

  sqlite3DbFree(p->db, cur);
  return SQLITE_OK;
}

/* Return TRUE if the jsonEachCursor object has been advanced off the end
** of the JSON object */
static int jsonEachEof(sqlite3_vtab_cursor *cur){
  JsonEachCursor *p = (JsonEachCursor*)cur;
  return p->i >= p->iEnd;
}

/*
** If the cursor is currently pointing at the label of a object entry,
** then return the index of the value.  For all other cases, return the
** current pointer position, which is the value.
*/
static int jsonSkipLabel(JsonEachCursor *p){
  if( p->eType==JSONB_OBJECT ){
    u32 sz = 0;
    u32 n = jsonbPayloadSize(&p->sParse, p->i, &sz);
    return p->i + n + sz;
  }else{
    return p->i;
  }
}

/*
** Append the path name for the current element.
*/
static void jsonAppendPathName(JsonEachCursor *p){
  assert( p->nParent>0 );
  assert( p->eType==JSONB_ARRAY || p->eType==JSONB_OBJECT );
  if( p->eType==JSONB_ARRAY ){
    jsonPrintf(30, &p->path, "[%lld]", p->aParent[p->nParent-1].iKey);
  }else{
    u32 n, sz = 0, k, i;
    const char *z;
    int needQuote = 0;
    n = jsonbPayloadSize(&p->sParse, p->i, &sz);
    k = p->i + n;
    z = (const char*)&p->sParse.aBlob[k];
    if( sz==0 || !sqlite3Isalpha(z[0]) ){
      needQuote = 1;
    }else{
      for(i=0; i<sz; i++){
        if( !sqlite3Isalnum(z[i]) ){
          needQuote = 1;
          break;
        }
      }
    }
    if( needQuote ){
      jsonPrintf(sz+4,&p->path,".\"%.*s\"", sz, z);
    }else{
      jsonPrintf(sz+2,&p->path,".%.*s", sz, z);
    }
  }
}

/* Advance the cursor to the next element for json_tree() */
static int jsonEachNext(sqlite3_vtab_cursor *cur){
  JsonEachCursor *p = (JsonEachCursor*)cur;
  int rc = SQLITE_OK;
  if( p->bRecursive ){
    u8 x;
    u8 levelChange = 0;
    u32 n, sz = 0;
    u32 i = jsonSkipLabel(p);
    x = p->sParse.aBlob[i] & 0x0f;
    n = jsonbPayloadSize(&p->sParse, i, &sz);
    if( x==JSONB_OBJECT || x==JSONB_ARRAY ){
      JsonParent *pParent;
      if( p->nParent>=p->nParentAlloc ){
        JsonParent *pNew;
        u64 nNew;
        nNew = p->nParentAlloc*2 + 3;
        pNew = sqlite3DbRealloc(p->db, p->aParent, sizeof(JsonParent)*nNew);
        if( pNew==0 ) return SQLITE_NOMEM;
        p->nParentAlloc = (u32)nNew;
        p->aParent = pNew;
      }
      levelChange = 1;
      pParent = &p->aParent[p->nParent];
      pParent->iHead = p->i;
      pParent->iValue = i;
      pParent->iEnd = i + n + sz;
      pParent->iKey = -1;
      pParent->nPath = (u32)p->path.nUsed;
      if( p->eType && p->nParent ){
        jsonAppendPathName(p);
        if( p->path.eErr ) rc = SQLITE_NOMEM;
      }
      p->nParent++;
      p->i = i + n;
    }else{
      p->i = i + n + sz;
    }
    while( p->nParent>0 && p->i >= p->aParent[p->nParent-1].iEnd ){
      p->nParent--;
      p->path.nUsed = p->aParent[p->nParent].nPath;
      levelChange = 1;
    }
    if( levelChange ){
      if( p->nParent>0 ){
        JsonParent *pParent = &p->aParent[p->nParent-1];
        u32 iVal = pParent->iValue;
        p->eType = p->sParse.aBlob[iVal] & 0x0f;
      }else{
        p->eType = 0;
      }
    }
  }else{
    u32 n, sz = 0;
    u32 i = jsonSkipLabel(p);
    n = jsonbPayloadSize(&p->sParse, i, &sz);
    p->i = i + n + sz;
  }
  if( p->eType==JSONB_ARRAY && p->nParent ){
    p->aParent[p->nParent-1].iKey++;
  }
  p->iRowid++;
  return rc;
}

/* Length of the path for rowid==0 in bRecursive mode.
*/
static int jsonEachPathLength(JsonEachCursor *p){
  u32 n = p->path.nUsed;
  char *z = p->path.zBuf;
  if( p->iRowid==0 && p->bRecursive && n>=2 ){
    while( n>1 ){
      n--;
      if( z[n]=='[' || z[n]=='.' ){
        u32 x, sz = 0;
        char cSaved = z[n];
        z[n] = 0;
        assert( p->sParse.eEdit==0 );
        x = jsonLookupStep(&p->sParse, 0, z+1, 0);
        z[n] = cSaved;
        if( JSON_LOOKUP_ISERROR(x) ) continue;
        if( x + jsonbPayloadSize(&p->sParse, x, &sz) == p->i ) break;
      }
    }
  }
  return n;
}

/* Return the value of a column */
static int jsonEachColumn(
  sqlite3_vtab_cursor *cur,   /* The cursor */
  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
  int iColumn                 /* Which column to return */
){
  JsonEachCursor *p = (JsonEachCursor*)cur;
  switch( iColumn ){
    case JEACH_KEY: {
      if( p->nParent==0 ){
        u32 n, j;
        if( p->nRoot==1 ) break;
        j = jsonEachPathLength(p);
        n = p->nRoot - j;
        if( n==0 ){
          break;
        }else if( p->path.zBuf[j]=='[' ){
          i64 x;
          sqlite3Atoi64(&p->path.zBuf[j+1], &x, n-1, SQLITE_UTF8);
          sqlite3_result_int64(ctx, x);
        }else if( p->path.zBuf[j+1]=='"' ){
          sqlite3_result_text(ctx, &p->path.zBuf[j+2], n-3, SQLITE_TRANSIENT);
        }else{
          sqlite3_result_text(ctx, &p->path.zBuf[j+1], n-1, SQLITE_TRANSIENT);
        }
        break;
      }
      if( p->eType==JSONB_OBJECT ){
        jsonReturnFromBlob(&p->sParse, p->i, ctx, 1);
      }else{
        assert( p->eType==JSONB_ARRAY );
        sqlite3_result_int64(ctx, p->aParent[p->nParent-1].iKey);
      }
      break;
    }
    case JEACH_VALUE: {
      u32 i = jsonSkipLabel(p);
      jsonReturnFromBlob(&p->sParse, i, ctx, p->eMode);
      if( (p->sParse.aBlob[i] & 0x0f)>=JSONB_ARRAY ){
        sqlite3_result_subtype(ctx, JSON_SUBTYPE);
      }
      break;
    }
    case JEACH_TYPE: {
      u32 i = jsonSkipLabel(p);
      u8 eType = p->sParse.aBlob[i] & 0x0f;
      sqlite3_result_text(ctx, jsonbType[eType], -1, SQLITE_STATIC);
      break;
    }
    case JEACH_ATOM: {
      u32 i = jsonSkipLabel(p);
      if( (p->sParse.aBlob[i] & 0x0f)<JSONB_ARRAY ){
        jsonReturnFromBlob(&p->sParse, i, ctx, 1);
      }
      break;
    }
    case JEACH_ID: {
      sqlite3_result_int64(ctx, (sqlite3_int64)p->i);
      break;
    }
    case JEACH_PARENT: {
      if( p->nParent>0 && p->bRecursive ){
        sqlite3_result_int64(ctx, p->aParent[p->nParent-1].iHead);
      }
      break;
    }
    case JEACH_FULLKEY: {
      u64 nBase = p->path.nUsed;
      if( p->nParent ) jsonAppendPathName(p);
      sqlite3_result_text64(ctx, p->path.zBuf, p->path.nUsed,
                            SQLITE_TRANSIENT, SQLITE_UTF8);
      p->path.nUsed = nBase;
      break;
    }
    case JEACH_PATH: {
      u32 n = jsonEachPathLength(p);
      sqlite3_result_text64(ctx, p->path.zBuf, n,
                            SQLITE_TRANSIENT, SQLITE_UTF8);
      break;
    }
    default: {
      sqlite3_result_text(ctx, p->path.zBuf, p->nRoot, SQLITE_STATIC);
      break;
    }
    case JEACH_JSON: {
      if( p->sParse.zJson==0 ){
        sqlite3_result_blob(ctx, p->sParse.aBlob, p->sParse.nBlob,
                            SQLITE_TRANSIENT);
      }else{
        sqlite3_result_text(ctx, p->sParse.zJson, -1, SQLITE_TRANSIENT);
      }
      break;
    }
  }
  return SQLITE_OK;
}

/* Return the current rowid value */
static int jsonEachRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  JsonEachCursor *p = (JsonEachCursor*)cur;
  *pRowid = p->iRowid;
  return SQLITE_OK;
}

/* The query strategy is to look for an equality constraint on the json
** column.  Without such a constraint, the table cannot operate.  idxNum is
** 1 if the constraint is found, 3 if the constraint and zRoot are found,
** and 0 otherwise.
*/
static int jsonEachBestIndex(
  sqlite3_vtab *tab,
  sqlite3_index_info *pIdxInfo
){
  int i;                     /* Loop counter or computed array index */
  int aIdx[2];               /* Index of constraints for JSON and ROOT */
  int unusableMask = 0;      /* Mask of unusable JSON and ROOT constraints */
  int idxMask = 0;           /* Mask of usable == constraints JSON and ROOT */
  const struct sqlite3_index_constraint *pConstraint;

  /* This implementation assumes that JSON and ROOT are the last two
  ** columns in the table */
  assert( JEACH_ROOT == JEACH_JSON+1 );
  UNUSED_PARAMETER(tab);
  aIdx[0] = aIdx[1] = -1;
  pConstraint = pIdxInfo->aConstraint;
  for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
    int iCol;
    int iMask;
    if( pConstraint->iColumn < JEACH_JSON ) continue;
    iCol = pConstraint->iColumn - JEACH_JSON;
    assert( iCol==0 || iCol==1 );
    testcase( iCol==0 );
    iMask = 1 << iCol;
    if( pConstraint->usable==0 ){
      unusableMask |= iMask;
    }else if( pConstraint->op==SQLITE_INDEX_CONSTRAINT_EQ ){
      aIdx[iCol] = i;
      idxMask |= iMask;
    }
  }
  if( pIdxInfo->nOrderBy>0
   && pIdxInfo->aOrderBy[0].iColumn<0
   && pIdxInfo->aOrderBy[0].desc==0
  ){
    pIdxInfo->orderByConsumed = 1;
  }

  if( (unusableMask & ~idxMask)!=0 ){
    /* If there are any unusable constraints on JSON or ROOT, then reject
    ** this entire plan */
    return SQLITE_CONSTRAINT;
  }
  if( aIdx[0]<0 ){
    /* No JSON input.  Leave estimatedCost at the huge value that it was
    ** initialized to to discourage the query planner from selecting this
    ** plan. */
    pIdxInfo->idxNum = 0;
  }else{
    pIdxInfo->estimatedCost = 1.0;
    i = aIdx[0];
    pIdxInfo->aConstraintUsage[i].argvIndex = 1;
    pIdxInfo->aConstraintUsage[i].omit = 1;
    if( aIdx[1]<0 ){
      pIdxInfo->idxNum = 1;  /* Only JSON supplied.  Plan 1 */
    }else{
      i = aIdx[1];
      pIdxInfo->aConstraintUsage[i].argvIndex = 2;
      pIdxInfo->aConstraintUsage[i].omit = 1;
      pIdxInfo->idxNum = 3;  /* Both JSON and ROOT are supplied.  Plan 3 */
    }
  }
  return SQLITE_OK;
}

/* Start a search on a new JSON string */
static int jsonEachFilter(
  sqlite3_vtab_cursor *cur,
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  JsonEachCursor *p = (JsonEachCursor*)cur;
  const char *zRoot = 0;
  u32 i, n, sz;

  UNUSED_PARAMETER(idxStr);
  UNUSED_PARAMETER(argc);
  jsonEachCursorReset(p);
  if( idxNum==0 ) return SQLITE_OK;
  memset(&p->sParse, 0, sizeof(p->sParse));
  p->sParse.nJPRef = 1;
  p->sParse.db = p->db;
  if( jsonArgIsJsonb(argv[0], &p->sParse) ){
    /* We have JSONB */
  }else{
    p->sParse.zJson = (char*)sqlite3_value_text(argv[0]);
    p->sParse.nJson = sqlite3_value_bytes(argv[0]);
    if( p->sParse.zJson==0 ){
      p->i = p->iEnd = 0;
      return SQLITE_OK;
    }
    if( jsonConvertTextToBlob(&p->sParse, 0) ){
      if( p->sParse.oom ){
        return SQLITE_NOMEM;
      }
      goto json_each_malformed_input;
    }
  }
  if( idxNum==3 ){
    zRoot = (const char*)sqlite3_value_text(argv[1]);
    if( zRoot==0 ) return SQLITE_OK;
    if( zRoot[0]!='$' ){
      sqlite3_free(cur->pVtab->zErrMsg);
      cur->pVtab->zErrMsg = jsonBadPathError(0, zRoot);
      jsonEachCursorReset(p);
      return cur->pVtab->zErrMsg ? SQLITE_ERROR : SQLITE_NOMEM;
    }
    p->nRoot = sqlite3Strlen30(zRoot);
    if( zRoot[1]==0 ){
      i = p->i = 0;
      p->eType = 0;
    }else{
      i = jsonLookupStep(&p->sParse, 0, zRoot+1, 0);
      if( JSON_LOOKUP_ISERROR(i) ){
        if( i==JSON_LOOKUP_NOTFOUND ){
          p->i = 0;
          p->eType = 0;
          p->iEnd = 0;
          return SQLITE_OK;
        }
        sqlite3_free(cur->pVtab->zErrMsg);
        cur->pVtab->zErrMsg = jsonBadPathError(0, zRoot);
        jsonEachCursorReset(p);
        return cur->pVtab->zErrMsg ? SQLITE_ERROR : SQLITE_NOMEM;
      }
      if( p->sParse.iLabel ){
        p->i = p->sParse.iLabel;
        p->eType = JSONB_OBJECT;
      }else{
        p->i = i;
        p->eType = JSONB_ARRAY;
      }
    }
    jsonAppendRaw(&p->path, zRoot, p->nRoot);
  }else{
    i = p->i = 0;
    p->eType = 0;
    p->nRoot = 1;
    jsonAppendRaw(&p->path, "$", 1);
  }
  p->nParent = 0;
  n = jsonbPayloadSize(&p->sParse, i, &sz);
  p->iEnd = i+n+sz;
  if( (p->sParse.aBlob[i] & 0x0f)>=JSONB_ARRAY && !p->bRecursive ){
    p->i = i + n;
    p->eType = p->sParse.aBlob[i] & 0x0f;
    p->aParent = sqlite3DbMallocZero(p->db, sizeof(JsonParent));
    if( p->aParent==0 ) return SQLITE_NOMEM;
    p->nParent = 1;
    p->nParentAlloc = 1;
    p->aParent[0].iKey = 0;
    p->aParent[0].iEnd = p->iEnd;
    p->aParent[0].iHead = p->i;
    p->aParent[0].iValue = i;
  }
  return SQLITE_OK;

json_each_malformed_input:
  sqlite3_free(cur->pVtab->zErrMsg);
  cur->pVtab->zErrMsg = sqlite3_mprintf("malformed JSON");
  jsonEachCursorReset(p);
  return cur->pVtab->zErrMsg ? SQLITE_ERROR : SQLITE_NOMEM;
}

/* The methods of the json_each virtual table */
static sqlite3_module jsonEachModule = {
  0,                         /* iVersion */
  0,                         /* xCreate */
  jsonEachConnect,           /* xConnect */
  jsonEachBestIndex,         /* xBestIndex */
  jsonEachDisconnect,        /* xDisconnect */
  0,                         /* xDestroy */
  jsonEachOpen,              /* xOpen - open a cursor */
  jsonEachClose,             /* xClose - close a cursor */
  jsonEachFilter,            /* xFilter - configure scan constraints */
  jsonEachNext,              /* xNext - advance a cursor */
  jsonEachEof,               /* xEof - check for end of scan */
  jsonEachColumn,            /* xColumn - read data */
  jsonEachRowid,             /* xRowid - read data */
  0,                         /* xUpdate */
  0,                         /* xBegin */
  0,                         /* xSync */
  0,                         /* xCommit */
  0,                         /* xRollback */
  0,                         /* xFindMethod */
  0,                         /* xRename */
  0,                         /* xSavepoint */
  0,                         /* xRelease */
  0,                         /* xRollbackTo */
  0,                         /* xShadowName */
  0                          /* xIntegrity */
};
#endif /* SQLITE_OMIT_VIRTUALTABLE */
#endif /* !defined(SQLITE_OMIT_JSON) */

/*
** Register JSON functions.
*/
SQLITE_PRIVATE void sqlite3RegisterJsonFunctions(void){
#ifndef SQLITE_OMIT_JSON
  static FuncDef aJsonFunc[] = {
    /*   sqlite3_result_subtype() ----,  ,--- sqlite3_value_subtype()       */
    /*                                |  |                                  */
    /*             Uses cache ------, |  | ,---- Returns JSONB              */
    /*                              | |  | |                                */
    /*     Number of arguments ---, | |  | | ,--- Flags                     */
    /*                            | | |  | | |                              */
    JFUNCTION(json,               1,1,1, 0,0,0,          jsonRemoveFunc),
    JFUNCTION(jsonb,              1,1,0, 0,1,0,          jsonRemoveFunc),
    JFUNCTION(json_array,        -1,0,1, 1,0,0,          jsonArrayFunc),
    JFUNCTION(jsonb_array,       -1,0,1, 1,1,0,          jsonArrayFunc),
    JFUNCTION(json_array_length,  1,1,0, 0,0,0,          jsonArrayLengthFunc),
    JFUNCTION(json_array_length,  2,1,0, 0,0,0,          jsonArrayLengthFunc),
    JFUNCTION(json_error_position,1,1,0, 0,0,0,          jsonErrorFunc),
    JFUNCTION(json_extract,      -1,1,1, 0,0,0,          jsonExtractFunc),
    JFUNCTION(jsonb_extract,     -1,1,0, 0,1,0,          jsonExtractFunc),
    JFUNCTION(->,                 2,1,1, 0,0,JSON_JSON,  jsonExtractFunc),
    JFUNCTION(->>,                2,1,0, 0,0,JSON_SQL,   jsonExtractFunc),
    JFUNCTION(json_insert,       -1,1,1, 1,0,0,          jsonSetFunc),
    JFUNCTION(jsonb_insert,      -1,1,0, 1,1,0,          jsonSetFunc),
    JFUNCTION(json_object,       -1,0,1, 1,0,0,          jsonObjectFunc),
    JFUNCTION(jsonb_object,      -1,0,1, 1,1,0,          jsonObjectFunc),
    JFUNCTION(json_patch,         2,1,1, 0,0,0,          jsonPatchFunc),
    JFUNCTION(jsonb_patch,        2,1,0, 0,1,0,          jsonPatchFunc),
    JFUNCTION(json_pretty,        1,1,0, 0,0,0,          jsonPrettyFunc),
    JFUNCTION(json_pretty,        2,1,0, 0,0,0,          jsonPrettyFunc),
    JFUNCTION(json_quote,         1,0,1, 1,0,0,          jsonQuoteFunc),
    JFUNCTION(json_remove,       -1,1,1, 0,0,0,          jsonRemoveFunc),
    JFUNCTION(jsonb_remove,      -1,1,0, 0,1,0,          jsonRemoveFunc),
    JFUNCTION(json_replace,      -1,1,1, 1,0,0,          jsonReplaceFunc),
    JFUNCTION(jsonb_replace,     -1,1,0, 1,1,0,          jsonReplaceFunc),
    JFUNCTION(json_set,          -1,1,1, 1,0,JSON_ISSET, jsonSetFunc),
    JFUNCTION(jsonb_set,         -1,1,0, 1,1,JSON_ISSET, jsonSetFunc),
    JFUNCTION(json_type,          1,1,0, 0,0,0,          jsonTypeFunc),
    JFUNCTION(json_type,          2,1,0, 0,0,0,          jsonTypeFunc),
    JFUNCTION(json_valid,         1,1,0, 0,0,0,          jsonValidFunc),

sqlite3.c  view on Meta::CPAN

# define UNUSED_PARAMETER(x) (void)(x)
#endif

typedef struct Rtree Rtree;
typedef struct RtreeCursor RtreeCursor;
typedef struct RtreeNode RtreeNode;
typedef struct RtreeCell RtreeCell;
typedef struct RtreeConstraint RtreeConstraint;
typedef struct RtreeMatchArg RtreeMatchArg;
typedef struct RtreeGeomCallback RtreeGeomCallback;
typedef union RtreeCoord RtreeCoord;
typedef struct RtreeSearchPoint RtreeSearchPoint;

/* The rtree may have between 1 and RTREE_MAX_DIMENSIONS dimensions. */
#define RTREE_MAX_DIMENSIONS 5

/* Maximum number of auxiliary columns */
#define RTREE_MAX_AUX_COLUMN 100

/* Size of hash table Rtree.aHash. This hash table is not expected to
** ever contain very many entries, so a fixed number of buckets is
** used.
*/
#define HASHSIZE 97

/* The xBestIndex method of this virtual table requires an estimate of
** the number of rows in the virtual table to calculate the costs of
** various strategies. If possible, this estimate is loaded from the
** sqlite_stat1 table (with RTREE_MIN_ROWEST as a hard-coded minimum).
** Otherwise, if no sqlite_stat1 entry is available, use
** RTREE_DEFAULT_ROWEST.
*/
#define RTREE_DEFAULT_ROWEST 1048576
#define RTREE_MIN_ROWEST         100

/*
** An rtree virtual-table object.
*/
struct Rtree {
  sqlite3_vtab base;          /* Base class.  Must be first */
  sqlite3 *db;                /* Host database connection */
  int iNodeSize;              /* Size in bytes of each node in the node table */
  u8 nDim;                    /* Number of dimensions */
  u8 nDim2;                   /* Twice the number of dimensions */
  u8 eCoordType;              /* RTREE_COORD_REAL32 or RTREE_COORD_INT32 */
  u8 nBytesPerCell;           /* Bytes consumed per cell */
  u8 inWrTrans;               /* True if inside write transaction */
  u8 nAux;                    /* # of auxiliary columns in %_rowid */
#ifdef SQLITE_ENABLE_GEOPOLY
  u8 nAuxNotNull;             /* Number of initial not-null aux columns */
#endif
#ifdef SQLITE_DEBUG
  u8 bCorrupt;                /* Shadow table corruption detected */
#endif
  int iDepth;                 /* Current depth of the r-tree structure */
  char *zDb;                  /* Name of database containing r-tree table */
  char *zName;                /* Name of r-tree table */
  char *zNodeName;            /* Name of the %_node table */
  u32 nBusy;                  /* Current number of users of this structure */
  i64 nRowEst;                /* Estimated number of rows in this table */
  u32 nCursor;                /* Number of open cursors */
  u32 nNodeRef;               /* Number RtreeNodes with positive nRef */
  char *zReadAuxSql;          /* SQL for statement to read aux data */

  /* List of nodes removed during a CondenseTree operation. List is
  ** linked together via the pointer normally used for hash chains -
  ** RtreeNode.pNext. RtreeNode.iNode stores the depth of the sub-tree
  ** headed by the node (leaf nodes have RtreeNode.iNode==0).
  */
  RtreeNode *pDeleted;

  /* Blob I/O on xxx_node */
  sqlite3_blob *pNodeBlob;

  /* Statements to read/write/delete a record from xxx_node */
  sqlite3_stmt *pWriteNode;
  sqlite3_stmt *pDeleteNode;

  /* Statements to read/write/delete a record from xxx_rowid */
  sqlite3_stmt *pReadRowid;
  sqlite3_stmt *pWriteRowid;
  sqlite3_stmt *pDeleteRowid;

  /* Statements to read/write/delete a record from xxx_parent */
  sqlite3_stmt *pReadParent;
  sqlite3_stmt *pWriteParent;
  sqlite3_stmt *pDeleteParent;

  /* Statement for writing to the "aux:" fields, if there are any */
  sqlite3_stmt *pWriteAux;

  RtreeNode *aHash[HASHSIZE]; /* Hash table of in-memory nodes. */
};

/* Possible values for Rtree.eCoordType: */
#define RTREE_COORD_REAL32 0
#define RTREE_COORD_INT32  1

/*
** If SQLITE_RTREE_INT_ONLY is defined, then this virtual table will
** only deal with integer coordinates.  No floating point operations
** will be done.
*/
#ifdef SQLITE_RTREE_INT_ONLY
  typedef sqlite3_int64 RtreeDValue;       /* High accuracy coordinate */
  typedef int RtreeValue;                  /* Low accuracy coordinate */
# define RTREE_ZERO 0
#else
  typedef double RtreeDValue;              /* High accuracy coordinate */
  typedef float RtreeValue;                /* Low accuracy coordinate */
# define RTREE_ZERO 0.0
#endif

/*
** Set the Rtree.bCorrupt flag
*/
#ifdef SQLITE_DEBUG
# define RTREE_IS_CORRUPT(X) ((X)->bCorrupt = 1)
#else
# define RTREE_IS_CORRUPT(X)
#endif

/*
** When doing a search of an r-tree, instances of the following structure
** record intermediate results from the tree walk.
**
** The id is always a node-id.  For iLevel>=1 the id is the node-id of
** the node that the RtreeSearchPoint represents.  When iLevel==0, however,
** the id is of the parent node and the cell that RtreeSearchPoint
** represents is the iCell-th entry in the parent node.
*/
struct RtreeSearchPoint {
  RtreeDValue rScore;    /* The score for this node.  Smallest goes first. */
  sqlite3_int64 id;      /* Node ID */
  u8 iLevel;             /* 0=entries.  1=leaf node.  2+ for higher */
  u8 eWithin;            /* PARTLY_WITHIN or FULLY_WITHIN */
  u8 iCell;              /* Cell index within the node */
};

/*
** The minimum number of cells allowed for a node is a third of the
** maximum. In Gutman's notation:
**
**     m = M/3
**
** If an R*-tree "Reinsert" operation is required, the same number of
** cells are removed from the overfull node and reinserted into the tree.
*/
#define RTREE_MINCELLS(p) ((((p)->iNodeSize-4)/(p)->nBytesPerCell)/3)
#define RTREE_REINSERT(p) RTREE_MINCELLS(p)
#define RTREE_MAXCELLS 51

/*
** The smallest possible node-size is (512-64)==448 bytes. And the largest
** supported cell size is 48 bytes (8 byte rowid + ten 4 byte coordinates).
** Therefore all non-root nodes must contain at least 3 entries. Since
** 3^40 is greater than 2^64, an r-tree structure always has a depth of
** 40 or less.
*/
#define RTREE_MAX_DEPTH 40


/*
** Number of entries in the cursor RtreeNode cache.  The first entry is
** used to cache the RtreeNode for RtreeCursor.sPoint.  The remaining
** entries cache the RtreeNode for the first elements of the priority queue.
*/
#define RTREE_CACHE_SZ  5

/*
** An rtree cursor object.
*/
struct RtreeCursor {
  sqlite3_vtab_cursor base;         /* Base class.  Must be first */
  u8 atEOF;                         /* True if at end of search */
  u8 bPoint;                        /* True if sPoint is valid */
  u8 bAuxValid;                     /* True if pReadAux is valid */
  int iStrategy;                    /* Copy of idxNum search parameter */
  int nConstraint;                  /* Number of entries in aConstraint */
  RtreeConstraint *aConstraint;     /* Search constraints. */
  int nPointAlloc;                  /* Number of slots allocated for aPoint[] */
  int nPoint;                       /* Number of slots used in aPoint[] */
  int mxLevel;                      /* iLevel value for root of the tree */
  RtreeSearchPoint *aPoint;         /* Priority queue for search points */
  sqlite3_stmt *pReadAux;           /* Statement to read aux-data */
  RtreeSearchPoint sPoint;          /* Cached next search point */
  RtreeNode *aNode[RTREE_CACHE_SZ]; /* Rtree node cache */
  u32 anQueue[RTREE_MAX_DEPTH+1];   /* Number of queued entries by iLevel */
};

/* Return the Rtree of a RtreeCursor */
#define RTREE_OF_CURSOR(X)   ((Rtree*)((X)->base.pVtab))

/*
** A coordinate can be either a floating point number or a integer.  All
** coordinates within a single R-Tree are always of the same time.
*/
union RtreeCoord {
  RtreeValue f;      /* Floating point value */
  int i;             /* Integer value */
  u32 u;             /* Unsigned for byte-order conversions */
};

/*
** The argument is an RtreeCoord. Return the value stored within the RtreeCoord
** formatted as a RtreeDValue (double or int64). This macro assumes that local
** variable pRtree points to the Rtree structure associated with the
** RtreeCoord.
*/
#ifdef SQLITE_RTREE_INT_ONLY
# define DCOORD(coord) ((RtreeDValue)coord.i)
#else
# define DCOORD(coord) (                           \
    (pRtree->eCoordType==RTREE_COORD_REAL32) ?      \
      ((double)coord.f) :                           \
      ((double)coord.i)                             \
  )
#endif

/*
** A search constraint.
*/
struct RtreeConstraint {
  int iCoord;                     /* Index of constrained coordinate */
  int op;                         /* Constraining operation */
  union {
    RtreeDValue rValue;             /* Constraint value. */
    int (*xGeom)(sqlite3_rtree_geometry*,int,RtreeDValue*,int*);
    int (*xQueryFunc)(sqlite3_rtree_query_info*);
  } u;
  sqlite3_rtree_query_info *pInfo;  /* xGeom and xQueryFunc argument */
};

/* Possible values for RtreeConstraint.op */
#define RTREE_EQ    0x41  /* A */
#define RTREE_LE    0x42  /* B */
#define RTREE_LT    0x43  /* C */
#define RTREE_GE    0x44  /* D */
#define RTREE_GT    0x45  /* E */
#define RTREE_MATCH 0x46  /* F: Old-style sqlite3_rtree_geometry_callback() */
#define RTREE_QUERY 0x47  /* G: New-style sqlite3_rtree_query_callback() */

/* Special operators available only on cursors.  Needs to be consecutive
** with the normal values above, but must be less than RTREE_MATCH.  These
** are used in the cursor for contraints such as x=NULL (RTREE_FALSE) or
** x<'xyz' (RTREE_TRUE) */
#define RTREE_TRUE  0x3f  /* ? */
#define RTREE_FALSE 0x40  /* @ */

/*
** An rtree structure node.
*/
struct RtreeNode {
  RtreeNode *pParent;         /* Parent node */
  i64 iNode;                  /* The node number */
  int nRef;                   /* Number of references to this node */
  int isDirty;                /* True if the node needs to be written to disk */
  u8 *zData;                  /* Content of the node, as should be on disk */
  RtreeNode *pNext;           /* Next node in this hash collision chain */
};

/* Return the number of cells in a node  */
#define NCELL(pNode) readInt16(&(pNode)->zData[2])

/*
** A single cell from a node, deserialized
*/
struct RtreeCell {
  i64 iRowid;                                 /* Node or entry ID */
  RtreeCoord aCoord[RTREE_MAX_DIMENSIONS*2];  /* Bounding box coordinates */
};


/*
** This object becomes the sqlite3_user_data() for the SQL functions
** that are created by sqlite3_rtree_geometry_callback() and
** sqlite3_rtree_query_callback() and which appear on the right of MATCH
** operators in order to constrain a search.
**
** xGeom and xQueryFunc are the callback functions.  Exactly one of
** xGeom and xQueryFunc fields is non-NULL, depending on whether the
** SQL function was created using sqlite3_rtree_geometry_callback() or
** sqlite3_rtree_query_callback().
**
** This object is deleted automatically by the destructor mechanism in
** sqlite3_create_function_v2().
*/
struct RtreeGeomCallback {
  int (*xGeom)(sqlite3_rtree_geometry*, int, RtreeDValue*, int*);
  int (*xQueryFunc)(sqlite3_rtree_query_info*);
  void (*xDestructor)(void*);
  void *pContext;
};

/*
** An instance of this structure (in the form of a BLOB) is returned by
** the SQL functions that sqlite3_rtree_geometry_callback() and
** sqlite3_rtree_query_callback() create, and is read as the right-hand
** operand to the MATCH operator of an R-Tree.
*/
struct RtreeMatchArg {
  u32 iSize;                  /* Size of this object */
  RtreeGeomCallback cb;       /* Info about the callback functions */
  int nParam;                 /* Number of parameters to the SQL function */
  sqlite3_value **apSqlParam; /* Original SQL parameter values */

sqlite3.c  view on Meta::CPAN

static void rtreeRelease(Rtree *pRtree){
  pRtree->nBusy--;
  if( pRtree->nBusy==0 ){
    pRtree->inWrTrans = 0;
    assert( pRtree->nCursor==0 );
    nodeBlobReset(pRtree);
    assert( pRtree->nNodeRef==0 || pRtree->bCorrupt );
    sqlite3_finalize(pRtree->pWriteNode);
    sqlite3_finalize(pRtree->pDeleteNode);
    sqlite3_finalize(pRtree->pReadRowid);
    sqlite3_finalize(pRtree->pWriteRowid);
    sqlite3_finalize(pRtree->pDeleteRowid);
    sqlite3_finalize(pRtree->pReadParent);
    sqlite3_finalize(pRtree->pWriteParent);
    sqlite3_finalize(pRtree->pDeleteParent);
    sqlite3_finalize(pRtree->pWriteAux);
    sqlite3_free(pRtree->zReadAuxSql);
    sqlite3_free(pRtree);
  }
}

/*
** Rtree virtual table module xDisconnect method.
*/
static int rtreeDisconnect(sqlite3_vtab *pVtab){
  rtreeRelease((Rtree *)pVtab);
  return SQLITE_OK;
}

/*
** Rtree virtual table module xDestroy method.
*/
static int rtreeDestroy(sqlite3_vtab *pVtab){
  Rtree *pRtree = (Rtree *)pVtab;
  int rc;
  char *zCreate = sqlite3_mprintf(
    "DROP TABLE '%q'.'%q_node';"
    "DROP TABLE '%q'.'%q_rowid';"
    "DROP TABLE '%q'.'%q_parent';",
    pRtree->zDb, pRtree->zName,
    pRtree->zDb, pRtree->zName,
    pRtree->zDb, pRtree->zName
  );
  if( !zCreate ){
    rc = SQLITE_NOMEM;
  }else{
    nodeBlobReset(pRtree);
    rc = sqlite3_exec(pRtree->db, zCreate, 0, 0, 0);
    sqlite3_free(zCreate);
  }
  if( rc==SQLITE_OK ){
    rtreeRelease(pRtree);
  }

  return rc;
}

/*
** Rtree virtual table module xOpen method.
*/
static int rtreeOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
  int rc = SQLITE_NOMEM;
  Rtree *pRtree = (Rtree *)pVTab;
  RtreeCursor *pCsr;

  pCsr = (RtreeCursor *)sqlite3_malloc64(sizeof(RtreeCursor));
  if( pCsr ){
    memset(pCsr, 0, sizeof(RtreeCursor));
    pCsr->base.pVtab = pVTab;
    rc = SQLITE_OK;
    pRtree->nCursor++;
  }
  *ppCursor = (sqlite3_vtab_cursor *)pCsr;

  return rc;
}


/*
** Reset a cursor back to its initial state.
*/
static void resetCursor(RtreeCursor *pCsr){
  Rtree *pRtree = (Rtree *)(pCsr->base.pVtab);
  int ii;
  sqlite3_stmt *pStmt;
  if( pCsr->aConstraint ){
    int i;                        /* Used to iterate through constraint array */
    for(i=0; i<pCsr->nConstraint; i++){
      sqlite3_rtree_query_info *pInfo = pCsr->aConstraint[i].pInfo;
      if( pInfo ){
        if( pInfo->xDelUser ) pInfo->xDelUser(pInfo->pUser);
        sqlite3_free(pInfo);
      }
    }
    sqlite3_free(pCsr->aConstraint);
    pCsr->aConstraint = 0;
  }
  for(ii=0; ii<RTREE_CACHE_SZ; ii++) nodeRelease(pRtree, pCsr->aNode[ii]);
  sqlite3_free(pCsr->aPoint);
  pStmt = pCsr->pReadAux;
  memset(pCsr, 0, sizeof(RtreeCursor));
  pCsr->base.pVtab = (sqlite3_vtab*)pRtree;
  pCsr->pReadAux = pStmt;

  /* The following will only fail if the previous sqlite3_step() call failed,
  ** in which case the error has already been caught. This statement never
  ** encounters an error within an sqlite3_column_xxx() function, as it
  ** calls sqlite3_column_value(), which does not use malloc(). So it is safe
  ** to ignore the error code here.  */
  sqlite3_reset(pStmt);
}

/*
** Rtree virtual table module xClose method.
*/
static int rtreeClose(sqlite3_vtab_cursor *cur){
  Rtree *pRtree = (Rtree *)(cur->pVtab);
  RtreeCursor *pCsr = (RtreeCursor *)cur;
  assert( pRtree->nCursor>0 );
  resetCursor(pCsr);
  sqlite3_finalize(pCsr->pReadAux);
  sqlite3_free(pCsr);
  pRtree->nCursor--;
  if( pRtree->nCursor==0 && pRtree->inWrTrans==0 ){
    nodeBlobReset(pRtree);
  }
  return SQLITE_OK;
}

/*
** Rtree virtual table module xEof method.
**
** Return non-zero if the cursor does not currently point to a valid
** record (i.e if the scan has finished), or zero otherwise.
*/
static int rtreeEof(sqlite3_vtab_cursor *cur){
  RtreeCursor *pCsr = (RtreeCursor *)cur;
  return pCsr->atEOF;
}

/*
** Convert raw bits from the on-disk RTree record into a coordinate value.
** The on-disk format is big-endian and needs to be converted for little-
** endian platforms.  The on-disk record stores integer coordinates if
** eInt is true and it stores 32-bit floating point records if eInt is
** false.  a[] is the four bytes of the on-disk record to be decoded.
** Store the results in "r".
**
** There are five versions of this macro.  The last one is generic.  The
** other four are various architectures-specific optimizations.
*/
#if SQLITE_BYTEORDER==1234 && MSVC_VERSION>=1300
#define RTREE_DECODE_COORD(eInt, a, r) {                        \
    RtreeCoord c;    /* Coordinate decoded */                   \
    c.u = _byteswap_ulong(*(u32*)a);                            \
    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
}
#elif SQLITE_BYTEORDER==1234 && GCC_VERSION>=4003000
#define RTREE_DECODE_COORD(eInt, a, r) {                        \
    RtreeCoord c;    /* Coordinate decoded */                   \
    c.u = __builtin_bswap32(*(u32*)a);                          \
    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
}
#elif SQLITE_BYTEORDER==1234
#define RTREE_DECODE_COORD(eInt, a, r) {                        \
    RtreeCoord c;    /* Coordinate decoded */                   \
    memcpy(&c.u,a,4);                                           \
    c.u = ((c.u>>24)&0xff)|((c.u>>8)&0xff00)|                   \
          ((c.u&0xff)<<24)|((c.u&0xff00)<<8);                   \
    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
}
#elif SQLITE_BYTEORDER==4321
#define RTREE_DECODE_COORD(eInt, a, r) {                        \
    RtreeCoord c;    /* Coordinate decoded */                   \
    memcpy(&c.u,a,4);                                           \
    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
}
#else
#define RTREE_DECODE_COORD(eInt, a, r) {                        \
    RtreeCoord c;    /* Coordinate decoded */                   \
    c.u = ((u32)a[0]<<24) + ((u32)a[1]<<16)                     \
           +((u32)a[2]<<8) + a[3];                              \
    r = eInt ? (sqlite3_rtree_dbl)c.i : (sqlite3_rtree_dbl)c.f; \
}
#endif

/*
** Check the RTree node or entry given by pCellData and p against the MATCH
** constraint pConstraint.
*/
static int rtreeCallbackConstraint(
  RtreeConstraint *pConstraint,  /* The constraint to test */
  int eInt,                      /* True if RTree holding integer coordinates */
  u8 *pCellData,                 /* Raw cell content */
  RtreeSearchPoint *pSearch,     /* Container of this cell */
  sqlite3_rtree_dbl *prScore,    /* OUT: score for the cell */

sqlite3.c  view on Meta::CPAN


/*
** One of the cells in node pNode is guaranteed to have a 64-bit
** integer value equal to iRowid. Return the index of this cell.
*/
static int nodeRowidIndex(
  Rtree *pRtree,
  RtreeNode *pNode,
  i64 iRowid,
  int *piIndex
){
  int ii;
  int nCell = NCELL(pNode);
  assert( nCell<200 );
  for(ii=0; ii<nCell; ii++){
    if( nodeGetRowid(pRtree, pNode, ii)==iRowid ){
      *piIndex = ii;
      return SQLITE_OK;
    }
  }
  RTREE_IS_CORRUPT(pRtree);
  return SQLITE_CORRUPT_VTAB;
}

/*
** Return the index of the cell containing a pointer to node pNode
** in its parent. If pNode is the root node, return -1.
*/
static int nodeParentIndex(Rtree *pRtree, RtreeNode *pNode, int *piIndex){
  RtreeNode *pParent = pNode->pParent;
  if( ALWAYS(pParent) ){
    return nodeRowidIndex(pRtree, pParent, pNode->iNode, piIndex);
  }else{
    *piIndex = -1;
    return SQLITE_OK;
  }
}

/*
** Compare two search points.  Return negative, zero, or positive if the first
** is less than, equal to, or greater than the second.
**
** The rScore is the primary key.  Smaller rScore values come first.
** If the rScore is a tie, then use iLevel as the tie breaker with smaller
** iLevel values coming first.  In this way, if rScore is the same for all
** SearchPoints, then iLevel becomes the deciding factor and the result
** is a depth-first search, which is the desired default behavior.
*/
static int rtreeSearchPointCompare(
  const RtreeSearchPoint *pA,
  const RtreeSearchPoint *pB
){
  if( pA->rScore<pB->rScore ) return -1;
  if( pA->rScore>pB->rScore ) return +1;
  if( pA->iLevel<pB->iLevel ) return -1;
  if( pA->iLevel>pB->iLevel ) return +1;
  return 0;
}

/*
** Interchange two search points in a cursor.
*/
static void rtreeSearchPointSwap(RtreeCursor *p, int i, int j){
  RtreeSearchPoint t = p->aPoint[i];
  assert( i<j );
  p->aPoint[i] = p->aPoint[j];
  p->aPoint[j] = t;
  i++; j++;
  if( i<RTREE_CACHE_SZ ){
    if( j>=RTREE_CACHE_SZ ){
      nodeRelease(RTREE_OF_CURSOR(p), p->aNode[i]);
      p->aNode[i] = 0;
    }else{
      RtreeNode *pTemp = p->aNode[i];
      p->aNode[i] = p->aNode[j];
      p->aNode[j] = pTemp;
    }
  }
}

/*
** Return the search point with the lowest current score.
*/
static RtreeSearchPoint *rtreeSearchPointFirst(RtreeCursor *pCur){
  return pCur->bPoint ? &pCur->sPoint : pCur->nPoint ? pCur->aPoint : 0;
}

/*
** Get the RtreeNode for the search point with the lowest score.
*/
static RtreeNode *rtreeNodeOfFirstSearchPoint(RtreeCursor *pCur, int *pRC){
  sqlite3_int64 id;
  int ii = 1 - pCur->bPoint;
  assert( ii==0 || ii==1 );
  assert( pCur->bPoint || pCur->nPoint );
  if( pCur->aNode[ii]==0 ){
    assert( pRC!=0 );
    id = ii ? pCur->aPoint[0].id : pCur->sPoint.id;
    *pRC = nodeAcquire(RTREE_OF_CURSOR(pCur), id, 0, &pCur->aNode[ii]);
  }
  return pCur->aNode[ii];
}

/*
** Push a new element onto the priority queue
*/
static RtreeSearchPoint *rtreeEnqueue(
  RtreeCursor *pCur,    /* The cursor */
  RtreeDValue rScore,   /* Score for the new search point */
  u8 iLevel             /* Level for the new search point */
){
  int i, j;
  RtreeSearchPoint *pNew;
  if( pCur->nPoint>=pCur->nPointAlloc ){
    int nNew = pCur->nPointAlloc*2 + 8;
    pNew = sqlite3_realloc64(pCur->aPoint, nNew*sizeof(pCur->aPoint[0]));
    if( pNew==0 ) return 0;
    pCur->aPoint = pNew;
    pCur->nPointAlloc = nNew;
  }
  i = pCur->nPoint++;
  pNew = pCur->aPoint + i;
  pNew->rScore = rScore;
  pNew->iLevel = iLevel;
  assert( iLevel<=RTREE_MAX_DEPTH );
  while( i>0 ){
    RtreeSearchPoint *pParent;
    j = (i-1)/2;
    pParent = pCur->aPoint + j;
    if( rtreeSearchPointCompare(pNew, pParent)>=0 ) break;
    rtreeSearchPointSwap(pCur, j, i);
    i = j;
    pNew = pParent;
  }
  return pNew;
}

/*
** Allocate a new RtreeSearchPoint and return a pointer to it.  Return
** NULL if malloc fails.
*/
static RtreeSearchPoint *rtreeSearchPointNew(
  RtreeCursor *pCur,    /* The cursor */
  RtreeDValue rScore,   /* Score for the new search point */
  u8 iLevel             /* Level for the new search point */
){
  RtreeSearchPoint *pNew, *pFirst;
  pFirst = rtreeSearchPointFirst(pCur);
  pCur->anQueue[iLevel]++;
  if( pFirst==0
   || pFirst->rScore>rScore
   || (pFirst->rScore==rScore && pFirst->iLevel>iLevel)
  ){
    if( pCur->bPoint ){
      int ii;
      pNew = rtreeEnqueue(pCur, rScore, iLevel);
      if( pNew==0 ) return 0;
      ii = (int)(pNew - pCur->aPoint) + 1;
      assert( ii==1 );
      if( ALWAYS(ii<RTREE_CACHE_SZ) ){
        assert( pCur->aNode[ii]==0 );
        pCur->aNode[ii] = pCur->aNode[0];
      }else{
        nodeRelease(RTREE_OF_CURSOR(pCur), pCur->aNode[0]);
      }
      pCur->aNode[0] = 0;
      *pNew = pCur->sPoint;
    }
    pCur->sPoint.rScore = rScore;
    pCur->sPoint.iLevel = iLevel;
    pCur->bPoint = 1;
    return &pCur->sPoint;
  }else{
    return rtreeEnqueue(pCur, rScore, iLevel);
  }
}

#if 0
/* Tracing routines for the RtreeSearchPoint queue */
static void tracePoint(RtreeSearchPoint *p, int idx, RtreeCursor *pCur){
  if( idx<0 ){ printf(" s"); }else{ printf("%2d", idx); }
  printf(" %d.%05lld.%02d %g %d",
    p->iLevel, p->id, p->iCell, p->rScore, p->eWithin
  );
  idx++;
  if( idx<RTREE_CACHE_SZ ){
    printf(" %p\n", pCur->aNode[idx]);
  }else{
    printf("\n");
  }
}
static void traceQueue(RtreeCursor *pCur, const char *zPrefix){
  int ii;
  printf("=== %9s ", zPrefix);
  if( pCur->bPoint ){
    tracePoint(&pCur->sPoint, -1, pCur);
  }
  for(ii=0; ii<pCur->nPoint; ii++){
    if( ii>0 || pCur->bPoint ) printf("              ");
    tracePoint(&pCur->aPoint[ii], ii, pCur);
  }
}
# define RTREE_QUEUE_TRACE(A,B) traceQueue(A,B)
#else
# define RTREE_QUEUE_TRACE(A,B)   /* no-op */
#endif

/* Remove the search point with the lowest current score.
*/
static void rtreeSearchPointPop(RtreeCursor *p){
  int i, j, k, n;
  i = 1 - p->bPoint;
  assert( i==0 || i==1 );
  if( p->aNode[i] ){
    nodeRelease(RTREE_OF_CURSOR(p), p->aNode[i]);
    p->aNode[i] = 0;
  }
  if( p->bPoint ){
    p->anQueue[p->sPoint.iLevel]--;
    p->bPoint = 0;
  }else if( ALWAYS(p->nPoint) ){
    p->anQueue[p->aPoint[0].iLevel]--;
    n = --p->nPoint;
    p->aPoint[0] = p->aPoint[n];
    if( n<RTREE_CACHE_SZ-1 ){
      p->aNode[1] = p->aNode[n+1];
      p->aNode[n+1] = 0;
    }
    i = 0;
    while( (j = i*2+1)<n ){
      k = j+1;
      if( k<n && rtreeSearchPointCompare(&p->aPoint[k], &p->aPoint[j])<0 ){
        if( rtreeSearchPointCompare(&p->aPoint[k], &p->aPoint[i])<0 ){
          rtreeSearchPointSwap(p, i, k);
          i = k;
        }else{
          break;
        }
      }else{
        if( rtreeSearchPointCompare(&p->aPoint[j], &p->aPoint[i])<0 ){
          rtreeSearchPointSwap(p, i, j);
          i = j;
        }else{
          break;
        }
      }
    }
  }
}


/*
** Continue the search on cursor pCur until the front of the queue
** contains an entry suitable for returning as a result-set row,
** or until the RtreeSearchPoint queue is empty, indicating that the
** query has completed.
*/
static int rtreeStepToLeaf(RtreeCursor *pCur){
  RtreeSearchPoint *p;
  Rtree *pRtree = RTREE_OF_CURSOR(pCur);
  RtreeNode *pNode;
  int eWithin;
  int rc = SQLITE_OK;
  int nCell;
  int nConstraint = pCur->nConstraint;
  int ii;
  int eInt;
  RtreeSearchPoint x;

  eInt = pRtree->eCoordType==RTREE_COORD_INT32;
  while( (p = rtreeSearchPointFirst(pCur))!=0 && p->iLevel>0 ){
    u8 *pCellData;
    pNode = rtreeNodeOfFirstSearchPoint(pCur, &rc);
    if( rc ) return rc;
    nCell = NCELL(pNode);
    assert( nCell<200 );
    pCellData = pNode->zData + (4+pRtree->nBytesPerCell*p->iCell);
    while( p->iCell<nCell ){
      sqlite3_rtree_dbl rScore = (sqlite3_rtree_dbl)-1;
      eWithin = FULLY_WITHIN;
      for(ii=0; ii<nConstraint; ii++){
        RtreeConstraint *pConstraint = pCur->aConstraint + ii;
        if( pConstraint->op>=RTREE_MATCH ){
          rc = rtreeCallbackConstraint(pConstraint, eInt, pCellData, p,
                                       &rScore, &eWithin);
          if( rc ) return rc;
        }else if( p->iLevel==1 ){
          rtreeLeafConstraint(pConstraint, eInt, pCellData, &eWithin);
        }else{
          rtreeNonleafConstraint(pConstraint, eInt, pCellData, &eWithin);
        }
        if( eWithin==NOT_WITHIN ){
          p->iCell++;
          pCellData += pRtree->nBytesPerCell;
          break;
        }
      }
      if( eWithin==NOT_WITHIN ) continue;
      p->iCell++;
      x.iLevel = p->iLevel - 1;
      if( x.iLevel ){
        x.id = readInt64(pCellData);
        for(ii=0; ii<pCur->nPoint; ii++){
          if( pCur->aPoint[ii].id==x.id ){
            RTREE_IS_CORRUPT(pRtree);
            return SQLITE_CORRUPT_VTAB;
          }
        }
        x.iCell = 0;
      }else{
        x.id = p->id;
        x.iCell = p->iCell - 1;
      }
      if( p->iCell>=nCell ){
        RTREE_QUEUE_TRACE(pCur, "POP-S:");
        rtreeSearchPointPop(pCur);
      }
      if( rScore<RTREE_ZERO ) rScore = RTREE_ZERO;
      p = rtreeSearchPointNew(pCur, rScore, x.iLevel);
      if( p==0 ) return SQLITE_NOMEM;
      p->eWithin = (u8)eWithin;
      p->id = x.id;
      p->iCell = x.iCell;
      RTREE_QUEUE_TRACE(pCur, "PUSH-S:");
      break;
    }
    if( p->iCell>=nCell ){
      RTREE_QUEUE_TRACE(pCur, "POP-Se:");
      rtreeSearchPointPop(pCur);
    }
  }
  pCur->atEOF = p==0;
  return SQLITE_OK;
}

/*
** Rtree virtual table module xNext method.
*/
static int rtreeNext(sqlite3_vtab_cursor *pVtabCursor){
  RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
  int rc = SQLITE_OK;

  /* Move to the next entry that matches the configured constraints. */
  RTREE_QUEUE_TRACE(pCsr, "POP-Nx:");
  if( pCsr->bAuxValid ){
    pCsr->bAuxValid = 0;
    sqlite3_reset(pCsr->pReadAux);
  }
  rtreeSearchPointPop(pCsr);
  rc = rtreeStepToLeaf(pCsr);
  return rc;
}

/*
** Rtree virtual table module xRowid method.
*/
static int rtreeRowid(sqlite3_vtab_cursor *pVtabCursor, sqlite_int64 *pRowid){
  RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
  RtreeSearchPoint *p = rtreeSearchPointFirst(pCsr);
  int rc = SQLITE_OK;
  RtreeNode *pNode = rtreeNodeOfFirstSearchPoint(pCsr, &rc);
  if( rc==SQLITE_OK && ALWAYS(p) ){
    if( p->iCell>=NCELL(pNode) ){
      rc = SQLITE_ABORT;
    }else{
      *pRowid = nodeGetRowid(RTREE_OF_CURSOR(pCsr), pNode, p->iCell);
    }
  }
  return rc;
}

/*
** Rtree virtual table module xColumn method.
*/
static int rtreeColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
  Rtree *pRtree = (Rtree *)cur->pVtab;
  RtreeCursor *pCsr = (RtreeCursor *)cur;
  RtreeSearchPoint *p = rtreeSearchPointFirst(pCsr);
  RtreeCoord c;
  int rc = SQLITE_OK;
  RtreeNode *pNode = rtreeNodeOfFirstSearchPoint(pCsr, &rc);

  if( rc ) return rc;
  if( NEVER(p==0) ) return SQLITE_OK;
  if( p->iCell>=NCELL(pNode) ) return SQLITE_ABORT;
  if( i==0 ){
    sqlite3_result_int64(ctx, nodeGetRowid(pRtree, pNode, p->iCell));
  }else if( i<=pRtree->nDim2 ){
    nodeGetCoord(pRtree, pNode, p->iCell, i-1, &c);
#ifndef SQLITE_RTREE_INT_ONLY
    if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
      sqlite3_result_double(ctx, c.f);
    }else
#endif
    {
      assert( pRtree->eCoordType==RTREE_COORD_INT32 );
      sqlite3_result_int(ctx, c.i);
    }
  }else{
    if( !pCsr->bAuxValid ){
      if( pCsr->pReadAux==0 ){
        rc = sqlite3_prepare_v3(pRtree->db, pRtree->zReadAuxSql, -1, 0,
                                &pCsr->pReadAux, 0);
        if( rc ) return rc;
      }
      sqlite3_bind_int64(pCsr->pReadAux, 1,
          nodeGetRowid(pRtree, pNode, p->iCell));
      rc = sqlite3_step(pCsr->pReadAux);
      if( rc==SQLITE_ROW ){
        pCsr->bAuxValid = 1;
      }else{
        sqlite3_reset(pCsr->pReadAux);
        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
        return rc;
      }
    }
    sqlite3_result_value(ctx,
         sqlite3_column_value(pCsr->pReadAux, i - pRtree->nDim2 + 1));
  }
  return SQLITE_OK;
}

/*
** Use nodeAcquire() to obtain the leaf node containing the record with
** rowid iRowid. If successful, set *ppLeaf to point to the node and
** return SQLITE_OK. If there is no such record in the table, set
** *ppLeaf to 0 and return SQLITE_OK. If an error occurs, set *ppLeaf
** to zero and return an SQLite error code.
*/
static int findLeafNode(
  Rtree *pRtree,              /* RTree to search */
  i64 iRowid,                 /* The rowid searching for */
  RtreeNode **ppLeaf,         /* Write the node here */
  sqlite3_int64 *piNode       /* Write the node-id here */
){
  int rc;
  *ppLeaf = 0;
  sqlite3_bind_int64(pRtree->pReadRowid, 1, iRowid);
  if( sqlite3_step(pRtree->pReadRowid)==SQLITE_ROW ){
    i64 iNode = sqlite3_column_int64(pRtree->pReadRowid, 0);
    if( piNode ) *piNode = iNode;
    rc = nodeAcquire(pRtree, iNode, 0, ppLeaf);
    sqlite3_reset(pRtree->pReadRowid);
  }else{
    rc = sqlite3_reset(pRtree->pReadRowid);
  }
  return rc;
}

/*
** This function is called to configure the RtreeConstraint object passed
** as the second argument for a MATCH constraint. The value passed as the
** first argument to this function is the right-hand operand to the MATCH
** operator.
*/
static int deserializeGeometry(sqlite3_value *pValue, RtreeConstraint *pCons){
  RtreeMatchArg *pBlob, *pSrc;       /* BLOB returned by geometry function */
  sqlite3_rtree_query_info *pInfo;   /* Callback information */

  pSrc = sqlite3_value_pointer(pValue, "RtreeMatchArg");
  if( pSrc==0 ) return SQLITE_ERROR;
  pInfo = (sqlite3_rtree_query_info*)
                sqlite3_malloc64( sizeof(*pInfo)+pSrc->iSize );
  if( !pInfo ) return SQLITE_NOMEM;
  memset(pInfo, 0, sizeof(*pInfo));
  pBlob = (RtreeMatchArg*)&pInfo[1];
  memcpy(pBlob, pSrc, pSrc->iSize);
  pInfo->pContext = pBlob->cb.pContext;
  pInfo->nParam = pBlob->nParam;
  pInfo->aParam = pBlob->aParam;
  pInfo->apSqlParam = pBlob->apSqlParam;

  if( pBlob->cb.xGeom ){
    pCons->u.xGeom = pBlob->cb.xGeom;
  }else{
    pCons->op = RTREE_QUERY;
    pCons->u.xQueryFunc = pBlob->cb.xQueryFunc;
  }
  pCons->pInfo = pInfo;
  return SQLITE_OK;
}

SQLITE_PRIVATE int sqlite3IntFloatCompare(i64,double);

/*
** Rtree virtual table module xFilter method.
*/
static int rtreeFilter(
  sqlite3_vtab_cursor *pVtabCursor,
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  Rtree *pRtree = (Rtree *)pVtabCursor->pVtab;
  RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
  RtreeNode *pRoot = 0;
  int ii;
  int rc = SQLITE_OK;
  int iCell = 0;

  rtreeReference(pRtree);

  /* Reset the cursor to the same state as rtreeOpen() leaves it in. */
  resetCursor(pCsr);

  pCsr->iStrategy = idxNum;
  if( idxNum==1 ){
    /* Special case - lookup by rowid. */
    RtreeNode *pLeaf;        /* Leaf on which the required cell resides */
    RtreeSearchPoint *p;     /* Search point for the leaf */
    i64 iRowid = sqlite3_value_int64(argv[0]);
    i64 iNode = 0;
    int eType = sqlite3_value_numeric_type(argv[0]);
    if( eType==SQLITE_INTEGER
     || (eType==SQLITE_FLOAT
         && 0==sqlite3IntFloatCompare(iRowid,sqlite3_value_double(argv[0])))
    ){
      rc = findLeafNode(pRtree, iRowid, &pLeaf, &iNode);
    }else{
      rc = SQLITE_OK;
      pLeaf = 0;
    }
    if( rc==SQLITE_OK && pLeaf!=0 ){
      p = rtreeSearchPointNew(pCsr, RTREE_ZERO, 0);
      assert( p!=0 );  /* Always returns pCsr->sPoint */
      pCsr->aNode[0] = pLeaf;
      p->id = iNode;
      p->eWithin = PARTLY_WITHIN;
      rc = nodeRowidIndex(pRtree, pLeaf, iRowid, &iCell);
      p->iCell = (u8)iCell;
      RTREE_QUEUE_TRACE(pCsr, "PUSH-F1:");
    }else{
      pCsr->atEOF = 1;
    }
  }else{
    /* Normal case - r-tree scan. Set up the RtreeCursor.aConstraint array
    ** with the configured constraints.
    */
    rc = nodeAcquire(pRtree, 1, 0, &pRoot);
    if( rc==SQLITE_OK && argc>0 ){
      pCsr->aConstraint = sqlite3_malloc64(sizeof(RtreeConstraint)*argc);
      pCsr->nConstraint = argc;
      if( !pCsr->aConstraint ){
        rc = SQLITE_NOMEM;
      }else{
        memset(pCsr->aConstraint, 0, sizeof(RtreeConstraint)*argc);
        memset(pCsr->anQueue, 0, sizeof(u32)*(pRtree->iDepth + 1));
        assert( (idxStr==0 && argc==0)
                || (idxStr && (int)strlen(idxStr)==argc*2) );
        for(ii=0; ii<argc; ii++){
          RtreeConstraint *p = &pCsr->aConstraint[ii];
          int eType = sqlite3_value_numeric_type(argv[ii]);
          p->op = idxStr[ii*2];
          p->iCoord = idxStr[ii*2+1]-'0';
          if( p->op>=RTREE_MATCH ){
            /* A MATCH operator. The right-hand-side must be a blob that
            ** can be cast into an RtreeMatchArg object. One created using
            ** an sqlite3_rtree_geometry_callback() SQL user function.
            */
            rc = deserializeGeometry(argv[ii], p);
            if( rc!=SQLITE_OK ){
              break;
            }

sqlite3.c  view on Meta::CPAN

** (at pRtree->base.zErrMsg) to an appropriate value and returns
** SQLITE_CONSTRAINT.
**
** Parameter iCol is the index of the leftmost column involved in the
** constraint failure. If it is 0, then the constraint that failed is
** the unique constraint on the id column. Otherwise, it is the rtree
** (c1<=c2) constraint on columns iCol and iCol+1 that has failed.
**
** If an OOM occurs, SQLITE_NOMEM is returned instead of SQLITE_CONSTRAINT.
*/
static int rtreeConstraintError(Rtree *pRtree, int iCol){
  sqlite3_stmt *pStmt = 0;
  char *zSql;
  int rc;

  assert( iCol==0 || iCol%2 );
  zSql = sqlite3_mprintf("SELECT * FROM %Q.%Q", pRtree->zDb, pRtree->zName);
  if( zSql ){
    rc = sqlite3_prepare_v2(pRtree->db, zSql, -1, &pStmt, 0);
  }else{
    rc = SQLITE_NOMEM;
  }
  sqlite3_free(zSql);

  if( rc==SQLITE_OK ){
    if( iCol==0 ){
      const char *zCol = sqlite3_column_name(pStmt, 0);
      pRtree->base.zErrMsg = sqlite3_mprintf(
          "UNIQUE constraint failed: %s.%s", pRtree->zName, zCol
      );
    }else{
      const char *zCol1 = sqlite3_column_name(pStmt, iCol);
      const char *zCol2 = sqlite3_column_name(pStmt, iCol+1);
      pRtree->base.zErrMsg = sqlite3_mprintf(
          "rtree constraint failed: %s.(%s<=%s)", pRtree->zName, zCol1, zCol2
      );
    }
  }

  sqlite3_finalize(pStmt);
  return (rc==SQLITE_OK ? SQLITE_CONSTRAINT : rc);
}



/*
** The xUpdate method for rtree module virtual tables.
*/
static int rtreeUpdate(
  sqlite3_vtab *pVtab,
  int nData,
  sqlite3_value **aData,
  sqlite_int64 *pRowid
){
  Rtree *pRtree = (Rtree *)pVtab;
  int rc = SQLITE_OK;
  RtreeCell cell;                 /* New cell to insert if nData>1 */
  int bHaveRowid = 0;             /* Set to 1 after new rowid is determined */

  if( pRtree->nNodeRef ){
    /* Unable to write to the btree while another cursor is reading from it,
    ** since the write might do a rebalance which would disrupt the read
    ** cursor. */
    return SQLITE_LOCKED_VTAB;
  }
  rtreeReference(pRtree);
  assert(nData>=1);

  memset(&cell, 0, sizeof(cell));

  /* Constraint handling. A write operation on an r-tree table may return
  ** SQLITE_CONSTRAINT for two reasons:
  **
  **   1. A duplicate rowid value, or
  **   2. The supplied data violates the "x2>=x1" constraint.
  **
  ** In the first case, if the conflict-handling mode is REPLACE, then
  ** the conflicting row can be removed before proceeding. In the second
  ** case, SQLITE_CONSTRAINT must be returned regardless of the
  ** conflict-handling mode specified by the user.
  */
  if( nData>1 ){
    int ii;
    int nn = nData - 4;

    if( nn > pRtree->nDim2 ) nn = pRtree->nDim2;
    /* Populate the cell.aCoord[] array. The first coordinate is aData[3].
    **
    ** NB: nData can only be less than nDim*2+3 if the rtree is mis-declared
    ** with "column" that are interpreted as table constraints.
    ** Example:  CREATE VIRTUAL TABLE bad USING rtree(x,y,CHECK(y>5));
    ** This problem was discovered after years of use, so we silently ignore
    ** these kinds of misdeclared tables to avoid breaking any legacy.
    */

#ifndef SQLITE_RTREE_INT_ONLY
    if( pRtree->eCoordType==RTREE_COORD_REAL32 ){
      for(ii=0; ii<nn; ii+=2){
        cell.aCoord[ii].f = rtreeValueDown(aData[ii+3]);
        cell.aCoord[ii+1].f = rtreeValueUp(aData[ii+4]);
        if( cell.aCoord[ii].f>cell.aCoord[ii+1].f ){
          rc = rtreeConstraintError(pRtree, ii+1);
          goto constraint;
        }
      }
    }else
#endif
    {
      for(ii=0; ii<nn; ii+=2){
        cell.aCoord[ii].i = sqlite3_value_int(aData[ii+3]);
        cell.aCoord[ii+1].i = sqlite3_value_int(aData[ii+4]);
        if( cell.aCoord[ii].i>cell.aCoord[ii+1].i ){
          rc = rtreeConstraintError(pRtree, ii+1);
          goto constraint;
        }
      }
    }

    /* If a rowid value was supplied, check if it is already present in
    ** the table. If so, the constraint has failed. */
    if( sqlite3_value_type(aData[2])!=SQLITE_NULL ){
      cell.iRowid = sqlite3_value_int64(aData[2]);
      if( sqlite3_value_type(aData[0])==SQLITE_NULL

sqlite3.c  view on Meta::CPAN

/*
** This function populates the pRtree->nRowEst variable with an estimate
** of the number of rows in the virtual table. If possible, this is based
** on sqlite_stat1 data. Otherwise, use RTREE_DEFAULT_ROWEST.
*/
static int rtreeQueryStat1(sqlite3 *db, Rtree *pRtree){
  const char *zFmt = "SELECT stat FROM %Q.sqlite_stat1 WHERE tbl = '%q_rowid'";
  char *zSql;
  sqlite3_stmt *p;
  int rc;
  i64 nRow = RTREE_MIN_ROWEST;

  rc = sqlite3_table_column_metadata(
      db, pRtree->zDb, "sqlite_stat1",0,0,0,0,0,0
  );
  if( rc!=SQLITE_OK ){
    pRtree->nRowEst = RTREE_DEFAULT_ROWEST;
    return rc==SQLITE_ERROR ? SQLITE_OK : rc;
  }
  zSql = sqlite3_mprintf(zFmt, pRtree->zDb, pRtree->zName);
  if( zSql==0 ){
    rc = SQLITE_NOMEM;
  }else{
    rc = sqlite3_prepare_v2(db, zSql, -1, &p, 0);
    if( rc==SQLITE_OK ){
      if( sqlite3_step(p)==SQLITE_ROW ) nRow = sqlite3_column_int64(p, 0);
      rc = sqlite3_finalize(p);
    }
    sqlite3_free(zSql);
  }
  pRtree->nRowEst = MAX(nRow, RTREE_MIN_ROWEST);
  return rc;
}


/*
** Return true if zName is the extension on one of the shadow tables used
** by this module.
*/
static int rtreeShadowName(const char *zName){
  static const char *azName[] = {
    "node", "parent", "rowid"
  };
  unsigned int i;
  for(i=0; i<sizeof(azName)/sizeof(azName[0]); i++){
    if( sqlite3_stricmp(zName, azName[i])==0 ) return 1;
  }
  return 0;
}

/* Forward declaration */
static int rtreeIntegrity(sqlite3_vtab*, const char*, const char*, int, char**);

static sqlite3_module rtreeModule = {
  4,                          /* iVersion */
  rtreeCreate,                /* xCreate - create a table */
  rtreeConnect,               /* xConnect - connect to an existing table */
  rtreeBestIndex,             /* xBestIndex - Determine search strategy */
  rtreeDisconnect,            /* xDisconnect - Disconnect from a table */
  rtreeDestroy,               /* xDestroy - Drop a table */
  rtreeOpen,                  /* xOpen - open a cursor */
  rtreeClose,                 /* xClose - close a cursor */
  rtreeFilter,                /* xFilter - configure scan constraints */
  rtreeNext,                  /* xNext - advance a cursor */
  rtreeEof,                   /* xEof */
  rtreeColumn,                /* xColumn - read data */
  rtreeRowid,                 /* xRowid - read data */
  rtreeUpdate,                /* xUpdate - write data */
  rtreeBeginTransaction,      /* xBegin - begin transaction */
  rtreeEndTransaction,        /* xSync - sync transaction */
  rtreeEndTransaction,        /* xCommit - commit transaction */
  rtreeRollback,              /* xRollback - rollback transaction */
  0,                          /* xFindFunction - function overloading */
  rtreeRename,                /* xRename - rename the table */
  rtreeSavepoint,             /* xSavepoint */
  0,                          /* xRelease */
  0,                          /* xRollbackTo */
  rtreeShadowName,            /* xShadowName */
  rtreeIntegrity              /* xIntegrity */
};

static int rtreeSqlInit(
  Rtree *pRtree,
  sqlite3 *db,
  const char *zDb,
  const char *zPrefix,
  int isCreate
){
  int rc = SQLITE_OK;

  #define N_STATEMENT 8
  static const char *azSql[N_STATEMENT] = {
    /* Write the xxx_node table */
    "INSERT OR REPLACE INTO '%q'.'%q_node' VALUES(?1, ?2)",
    "DELETE FROM '%q'.'%q_node' WHERE nodeno = ?1",

    /* Read and write the xxx_rowid table */
    "SELECT nodeno FROM '%q'.'%q_rowid' WHERE rowid = ?1",
    "INSERT OR REPLACE INTO '%q'.'%q_rowid' VALUES(?1, ?2)",
    "DELETE FROM '%q'.'%q_rowid' WHERE rowid = ?1",

    /* Read and write the xxx_parent table */
    "SELECT parentnode FROM '%q'.'%q_parent' WHERE nodeno = ?1",
    "INSERT OR REPLACE INTO '%q'.'%q_parent' VALUES(?1, ?2)",
    "DELETE FROM '%q'.'%q_parent' WHERE nodeno = ?1"
  };
  sqlite3_stmt **appStmt[N_STATEMENT];
  int i;
  const int f = SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_NO_VTAB;

  pRtree->db = db;

  if( isCreate ){
    char *zCreate;
    sqlite3_str *p = sqlite3_str_new(db);
    int ii;
    sqlite3_str_appendf(p,
       "CREATE TABLE \"%w\".\"%w_rowid\"(rowid INTEGER PRIMARY KEY,nodeno",
       zDb, zPrefix);
    for(ii=0; ii<pRtree->nAux; ii++){
      sqlite3_str_appendf(p,",a%d",ii);
    }
    sqlite3_str_appendf(p,
      ");CREATE TABLE \"%w\".\"%w_node\"(nodeno INTEGER PRIMARY KEY,data);",

sqlite3.c  view on Meta::CPAN

  rc = getNodeSize(db, pRtree, isCreate, pzErr);
  if( rc ) goto geopolyInit_fail;
  rc = rtreeSqlInit(pRtree, db, argv[1], argv[2], isCreate);
  if( rc ){
    *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(db));
    goto geopolyInit_fail;
  }

  *ppVtab = (sqlite3_vtab *)pRtree;
  return SQLITE_OK;

geopolyInit_fail:
  if( rc==SQLITE_OK ) rc = SQLITE_ERROR;
  assert( *ppVtab==0 );
  assert( pRtree->nBusy==1 );
  rtreeRelease(pRtree);
  return rc;
}


/*
** GEOPOLY virtual table module xCreate method.
*/
static int geopolyCreate(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  return geopolyInit(db, pAux, argc, argv, ppVtab, pzErr, 1);
}

/*
** GEOPOLY virtual table module xConnect method.
*/
static int geopolyConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  return geopolyInit(db, pAux, argc, argv, ppVtab, pzErr, 0);
}


/*
** GEOPOLY virtual table module xFilter method.
**
** Query plans:
**
**      1         rowid lookup
**      2         search for objects overlapping the same bounding box
**                that contains polygon argv[0]
**      3         search for objects overlapping the same bounding box
**                that contains polygon argv[0]
**      4         full table scan
*/
static int geopolyFilter(
  sqlite3_vtab_cursor *pVtabCursor,     /* The cursor to initialize */
  int idxNum,                           /* Query plan */
  const char *idxStr,                   /* Not Used */
  int argc, sqlite3_value **argv        /* Parameters to the query plan */
){
  Rtree *pRtree = (Rtree *)pVtabCursor->pVtab;
  RtreeCursor *pCsr = (RtreeCursor *)pVtabCursor;
  RtreeNode *pRoot = 0;
  int rc = SQLITE_OK;
  int iCell = 0;
  (void)idxStr;

  rtreeReference(pRtree);

  /* Reset the cursor to the same state as rtreeOpen() leaves it in. */
  resetCursor(pCsr);

  pCsr->iStrategy = idxNum;
  if( idxNum==1 ){
    /* Special case - lookup by rowid. */
    RtreeNode *pLeaf;        /* Leaf on which the required cell resides */
    RtreeSearchPoint *p;     /* Search point for the leaf */
    i64 iRowid = sqlite3_value_int64(argv[0]);
    i64 iNode = 0;
    rc = findLeafNode(pRtree, iRowid, &pLeaf, &iNode);
    if( rc==SQLITE_OK && pLeaf!=0 ){
      p = rtreeSearchPointNew(pCsr, RTREE_ZERO, 0);
      assert( p!=0 );  /* Always returns pCsr->sPoint */
      pCsr->aNode[0] = pLeaf;
      p->id = iNode;
      p->eWithin = PARTLY_WITHIN;
      rc = nodeRowidIndex(pRtree, pLeaf, iRowid, &iCell);
      p->iCell = (u8)iCell;
      RTREE_QUEUE_TRACE(pCsr, "PUSH-F1:");
    }else{
      pCsr->atEOF = 1;
    }
  }else{
    /* Normal case - r-tree scan. Set up the RtreeCursor.aConstraint array
    ** with the configured constraints.
    */
    rc = nodeAcquire(pRtree, 1, 0, &pRoot);
    if( rc==SQLITE_OK && idxNum<=3 ){
      RtreeCoord bbox[4];
      RtreeConstraint *p;
      assert( argc==1 );
      assert( argv[0]!=0 );
      geopolyBBox(0, argv[0], bbox, &rc);
      if( rc ){
        goto geopoly_filter_end;
      }
      pCsr->aConstraint = p = sqlite3_malloc(sizeof(RtreeConstraint)*4);
      pCsr->nConstraint = 4;
      if( p==0 ){
        rc = SQLITE_NOMEM;
      }else{
        memset(pCsr->aConstraint, 0, sizeof(RtreeConstraint)*4);
        memset(pCsr->anQueue, 0, sizeof(u32)*(pRtree->iDepth + 1));
        if( idxNum==2 ){
          /* Overlap query */
          p->op = 'B';
          p->iCoord = 0;
          p->u.rValue = bbox[1].f;
          p++;
          p->op = 'D';
          p->iCoord = 1;
          p->u.rValue = bbox[0].f;
          p++;
          p->op = 'B';
          p->iCoord = 2;
          p->u.rValue = bbox[3].f;
          p++;
          p->op = 'D';
          p->iCoord = 3;
          p->u.rValue = bbox[2].f;

sqlite3.c  view on Meta::CPAN

**   ------------------------------------------------
**     1        "rowid"       Direct lookup by rowid.
**     2        "rtree"       R-tree overlap query using geopoly_overlap()
**     3        "rtree"       R-tree within query using geopoly_within()
**     4        "fullscan"    full-table scan.
**   ------------------------------------------------
*/
static int geopolyBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
  int ii;
  int iRowidTerm = -1;
  int iFuncTerm = -1;
  int idxNum = 0;
  (void)tab;

  for(ii=0; ii<pIdxInfo->nConstraint; ii++){
    struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[ii];
    if( !p->usable ) continue;
    if( p->iColumn<0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ  ){
      iRowidTerm = ii;
      break;
    }
    if( p->iColumn==0 && p->op>=SQLITE_INDEX_CONSTRAINT_FUNCTION ){
      /* p->op==SQLITE_INDEX_CONSTRAINT_FUNCTION for geopoly_overlap()
      ** p->op==(SQLITE_INDEX_CONTRAINT_FUNCTION+1) for geopoly_within().
      ** See geopolyFindFunction() */
      iFuncTerm = ii;
      idxNum = p->op - SQLITE_INDEX_CONSTRAINT_FUNCTION + 2;
    }
  }

  if( iRowidTerm>=0 ){
    pIdxInfo->idxNum = 1;
    pIdxInfo->idxStr = "rowid";
    pIdxInfo->aConstraintUsage[iRowidTerm].argvIndex = 1;
    pIdxInfo->aConstraintUsage[iRowidTerm].omit = 1;
    pIdxInfo->estimatedCost = 30.0;
    pIdxInfo->estimatedRows = 1;
    pIdxInfo->idxFlags = SQLITE_INDEX_SCAN_UNIQUE;
    return SQLITE_OK;
  }
  if( iFuncTerm>=0 ){
    pIdxInfo->idxNum = idxNum;
    pIdxInfo->idxStr = "rtree";
    pIdxInfo->aConstraintUsage[iFuncTerm].argvIndex = 1;
    pIdxInfo->aConstraintUsage[iFuncTerm].omit = 0;
    pIdxInfo->estimatedCost = 300.0;
    pIdxInfo->estimatedRows = 10;
    return SQLITE_OK;
  }
  pIdxInfo->idxNum = 4;
  pIdxInfo->idxStr = "fullscan";
  pIdxInfo->estimatedCost = 3000000.0;
  pIdxInfo->estimatedRows = 100000;
  return SQLITE_OK;
}


/*
** GEOPOLY virtual table module xColumn method.
*/
static int geopolyColumn(sqlite3_vtab_cursor *cur, sqlite3_context *ctx, int i){
  Rtree *pRtree = (Rtree *)cur->pVtab;
  RtreeCursor *pCsr = (RtreeCursor *)cur;
  RtreeSearchPoint *p = rtreeSearchPointFirst(pCsr);
  int rc = SQLITE_OK;
  RtreeNode *pNode = rtreeNodeOfFirstSearchPoint(pCsr, &rc);

  if( rc ) return rc;
  if( p==0 ) return SQLITE_OK;
  if( i==0 && sqlite3_vtab_nochange(ctx) ) return SQLITE_OK;
  if( i<=pRtree->nAux ){
    if( !pCsr->bAuxValid ){
      if( pCsr->pReadAux==0 ){
        rc = sqlite3_prepare_v3(pRtree->db, pRtree->zReadAuxSql, -1, 0,
                                &pCsr->pReadAux, 0);
        if( rc ) return rc;
      }
      sqlite3_bind_int64(pCsr->pReadAux, 1,
          nodeGetRowid(pRtree, pNode, p->iCell));
      rc = sqlite3_step(pCsr->pReadAux);
      if( rc==SQLITE_ROW ){
        pCsr->bAuxValid = 1;
      }else{
        sqlite3_reset(pCsr->pReadAux);
        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
        return rc;
      }
    }
    sqlite3_result_value(ctx, sqlite3_column_value(pCsr->pReadAux, i+2));
  }
  return SQLITE_OK;
}


/*
** The xUpdate method for GEOPOLY module virtual tables.
**
** For DELETE:
**
**     argv[0] = the rowid to be deleted
**
** For INSERT:
**
**     argv[0] = SQL NULL
**     argv[1] = rowid to insert, or an SQL NULL to select automatically
**     argv[2] = _shape column
**     argv[3] = first application-defined column....
**
** For UPDATE:
**
**     argv[0] = rowid to modify.  Never NULL
**     argv[1] = rowid after the change.  Never NULL
**     argv[2] = new value for _shape
**     argv[3] = new value for first application-defined column....
*/
static int geopolyUpdate(
  sqlite3_vtab *pVtab,
  int nData,
  sqlite3_value **aData,
  sqlite_int64 *pRowid
){
  Rtree *pRtree = (Rtree *)pVtab;
  int rc = SQLITE_OK;
  RtreeCell cell;                 /* New cell to insert if nData>1 */
  i64 oldRowid;                   /* The old rowid */
  int oldRowidValid;              /* True if oldRowid is valid */
  i64 newRowid;                   /* The new rowid */
  int newRowidValid;              /* True if newRowid is valid */
  int coordChange = 0;            /* Change in coordinates */

  if( pRtree->nNodeRef ){
    /* Unable to write to the btree while another cursor is reading from it,
    ** since the write might do a rebalance which would disrupt the read
    ** cursor. */
    return SQLITE_LOCKED_VTAB;
  }
  rtreeReference(pRtree);
  assert(nData>=1);

  oldRowidValid = sqlite3_value_type(aData[0])!=SQLITE_NULL;;
  oldRowid = oldRowidValid ? sqlite3_value_int64(aData[0]) : 0;
  newRowidValid = nData>1 && sqlite3_value_type(aData[1])!=SQLITE_NULL;
  newRowid = newRowidValid ? sqlite3_value_int64(aData[1]) : 0;
  cell.iRowid = newRowid;

  if( nData>1                                 /* not a DELETE */
   && (!oldRowidValid                         /* INSERT */
        || !sqlite3_value_nochange(aData[2])  /* UPDATE _shape */
        || oldRowid!=newRowid)                /* Rowid change */
  ){
    assert( aData[2]!=0 );
    geopolyBBox(0, aData[2], cell.aCoord, &rc);
    if( rc ){
      if( rc==SQLITE_ERROR ){
        pVtab->zErrMsg =
          sqlite3_mprintf("_shape does not contain a valid polygon");
      }
      goto geopoly_update_end;
    }
    coordChange = 1;

    /* If a rowid value was supplied, check if it is already present in
    ** the table. If so, the constraint has failed. */
    if( newRowidValid && (!oldRowidValid || oldRowid!=newRowid) ){
      int steprc;
      sqlite3_bind_int64(pRtree->pReadRowid, 1, cell.iRowid);
      steprc = sqlite3_step(pRtree->pReadRowid);
      rc = sqlite3_reset(pRtree->pReadRowid);
      if( SQLITE_ROW==steprc ){
        if( sqlite3_vtab_on_conflict(pRtree->db)==SQLITE_REPLACE ){
          rc = rtreeDeleteRowid(pRtree, cell.iRowid);
        }else{
          rc = rtreeConstraintError(pRtree, 0);
        }
      }
    }
  }

  /* If aData[0] is not an SQL NULL value, it is the rowid of a
  ** record to delete from the r-tree table. The following block does
  ** just that.
  */
  if( rc==SQLITE_OK && (nData==1 || (coordChange && oldRowidValid)) ){
    rc = rtreeDeleteRowid(pRtree, oldRowid);
  }

  /* If the aData[] array contains more than one element, elements
  ** (aData[2]..aData[argc-1]) contain a new record to insert into
  ** the r-tree structure.
  */
  if( rc==SQLITE_OK && nData>1 && coordChange ){
    /* Insert the new record into the r-tree */
    RtreeNode *pLeaf = 0;
    if( !newRowidValid ){

sqlite3.c  view on Meta::CPAN

      if( sqlite3_value_type(aData[2])==SQLITE_TEXT
       && (p = geopolyFuncParam(0, aData[2], &rc))!=0
       && rc==SQLITE_OK
      ){
        sqlite3_bind_blob(pUp, 2, p->hdr, 4+8*p->nVertex, SQLITE_TRANSIENT);
      }else{
        sqlite3_bind_value(pUp, 2, aData[2]);
      }
      sqlite3_free(p);
      nChange = 1;
    }
    for(jj=1; jj<nData-2; jj++){
      nChange++;
      sqlite3_bind_value(pUp, jj+2, aData[jj+2]);
    }
    if( nChange ){
      sqlite3_step(pUp);
      rc = sqlite3_reset(pUp);
    }
  }

geopoly_update_end:
  rtreeRelease(pRtree);
  return rc;
}

/*
** Report that geopoly_overlap() is an overloaded function suitable
** for use in xBestIndex.
*/
static int geopolyFindFunction(
  sqlite3_vtab *pVtab,
  int nArg,
  const char *zName,
  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
  void **ppArg
){
  (void)pVtab;
  (void)nArg;
  if( sqlite3_stricmp(zName, "geopoly_overlap")==0 ){
    *pxFunc = geopolyOverlapFunc;
    *ppArg = 0;
    return SQLITE_INDEX_CONSTRAINT_FUNCTION;
  }
  if( sqlite3_stricmp(zName, "geopoly_within")==0 ){
    *pxFunc = geopolyWithinFunc;
    *ppArg = 0;
    return SQLITE_INDEX_CONSTRAINT_FUNCTION+1;
  }
  return 0;
}


static sqlite3_module geopolyModule = {
  3,                          /* iVersion */
  geopolyCreate,              /* xCreate - create a table */
  geopolyConnect,             /* xConnect - connect to an existing table */
  geopolyBestIndex,           /* xBestIndex - Determine search strategy */
  rtreeDisconnect,            /* xDisconnect - Disconnect from a table */
  rtreeDestroy,               /* xDestroy - Drop a table */
  rtreeOpen,                  /* xOpen - open a cursor */
  rtreeClose,                 /* xClose - close a cursor */
  geopolyFilter,              /* xFilter - configure scan constraints */
  rtreeNext,                  /* xNext - advance a cursor */
  rtreeEof,                   /* xEof */
  geopolyColumn,              /* xColumn - read data */
  rtreeRowid,                 /* xRowid - read data */
  geopolyUpdate,              /* xUpdate - write data */
  rtreeBeginTransaction,      /* xBegin - begin transaction */
  rtreeEndTransaction,        /* xSync - sync transaction */
  rtreeEndTransaction,        /* xCommit - commit transaction */
  rtreeEndTransaction,        /* xRollback - rollback transaction */
  geopolyFindFunction,        /* xFindFunction - function overloading */
  rtreeRename,                /* xRename - rename the table */
  rtreeSavepoint,             /* xSavepoint */
  0,                          /* xRelease */
  0,                          /* xRollbackTo */
  rtreeShadowName,            /* xShadowName */
  rtreeIntegrity              /* xIntegrity */
};

static int sqlite3_geopoly_init(sqlite3 *db){
  int rc = SQLITE_OK;
  static const struct {
    void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
    signed char nArg;
    unsigned char bPure;
    const char *zName;
  } aFunc[] = {
     { geopolyAreaFunc,          1, 1,    "geopoly_area"             },
     { geopolyBlobFunc,          1, 1,    "geopoly_blob"             },
     { geopolyJsonFunc,          1, 1,    "geopoly_json"             },
     { geopolySvgFunc,          -1, 1,    "geopoly_svg"              },
     { geopolyWithinFunc,        2, 1,    "geopoly_within"           },
     { geopolyContainsPointFunc, 3, 1,    "geopoly_contains_point"   },
     { geopolyOverlapFunc,       2, 1,    "geopoly_overlap"          },
     { geopolyDebugFunc,         1, 0,    "geopoly_debug"            },
     { geopolyBBoxFunc,          1, 1,    "geopoly_bbox"             },
     { geopolyXformFunc,         7, 1,    "geopoly_xform"            },
     { geopolyRegularFunc,       4, 1,    "geopoly_regular"          },
     { geopolyCcwFunc,           1, 1,    "geopoly_ccw"              },
  };
  static const struct {
    void (*xStep)(sqlite3_context*,int,sqlite3_value**);
    void (*xFinal)(sqlite3_context*);
    const char *zName;
  } aAgg[] = {
     { geopolyBBoxStep, geopolyBBoxFinal, "geopoly_group_bbox"    },
  };
  unsigned int i;
  for(i=0; i<sizeof(aFunc)/sizeof(aFunc[0]) && rc==SQLITE_OK; i++){
    int enc;
    if( aFunc[i].bPure ){
      enc = SQLITE_UTF8|SQLITE_DETERMINISTIC|SQLITE_INNOCUOUS;
    }else{
      enc = SQLITE_UTF8|SQLITE_DIRECTONLY;
    }
    rc = sqlite3_create_function(db, aFunc[i].zName, aFunc[i].nArg,
                                 enc, 0,
                                 aFunc[i].xFunc, 0, 0);
  }
  for(i=0; i<sizeof(aAgg)/sizeof(aAgg[0]) && rc==SQLITE_OK; i++){
    rc = sqlite3_create_function(db, aAgg[i].zName, 1,
              SQLITE_UTF8|SQLITE_DETERMINISTIC|SQLITE_INNOCUOUS, 0,

sqlite3.c  view on Meta::CPAN

        p->xFunc, 0, 0
    );
  }

  return rc;
}

#ifndef SQLITE_CORE
#ifdef _WIN32
__declspec(dllexport)
#endif
SQLITE_API int sqlite3_icu_init(
  sqlite3 *db,
  char **pzErrMsg,
  const sqlite3_api_routines *pApi
){
  SQLITE_EXTENSION_INIT2(pApi)
  return sqlite3IcuInit(db);
}
#endif

#endif

/************** End of icu.c *************************************************/
/************** Begin file fts3_icu.c ****************************************/
/*
** 2007 June 22
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file implements a tokenizer for fts3 based on the ICU library.
*/
/* #include "fts3Int.h" */
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
#ifdef SQLITE_ENABLE_ICU

/* #include <assert.h> */
/* #include <string.h> */
/* #include "fts3_tokenizer.h" */

#include <unicode/ubrk.h>
/* #include <unicode/ucol.h> */
/* #include <unicode/ustring.h> */
#include <unicode/utf16.h>

typedef struct IcuTokenizer IcuTokenizer;
typedef struct IcuCursor IcuCursor;

struct IcuTokenizer {
  sqlite3_tokenizer base;
  char *zLocale;
};

struct IcuCursor {
  sqlite3_tokenizer_cursor base;

  UBreakIterator *pIter;      /* ICU break-iterator object */
  int nChar;                  /* Number of UChar elements in pInput */
  UChar *aChar;               /* Copy of input using utf-16 encoding */
  int *aOffset;               /* Offsets of each character in utf-8 input */

  int nBuffer;
  char *zBuffer;

  int iToken;
};

/*
** Create a new tokenizer instance.
*/
static int icuCreate(
  int argc,                            /* Number of entries in argv[] */
  const char * const *argv,            /* Tokenizer creation arguments */
  sqlite3_tokenizer **ppTokenizer      /* OUT: Created tokenizer */
){
  IcuTokenizer *p;
  int n = 0;

  if( argc>0 ){
    n = strlen(argv[0])+1;
  }
  p = (IcuTokenizer *)sqlite3_malloc64(sizeof(IcuTokenizer)+n);
  if( !p ){
    return SQLITE_NOMEM;
  }
  memset(p, 0, sizeof(IcuTokenizer));

  if( n ){
    p->zLocale = (char *)&p[1];
    memcpy(p->zLocale, argv[0], n);
  }

  *ppTokenizer = (sqlite3_tokenizer *)p;

  return SQLITE_OK;
}

/*
** Destroy a tokenizer
*/
static int icuDestroy(sqlite3_tokenizer *pTokenizer){
  IcuTokenizer *p = (IcuTokenizer *)pTokenizer;
  sqlite3_free(p);
  return SQLITE_OK;
}

/*
** Prepare to begin tokenizing a particular string.  The input
** string to be tokenized is pInput[0..nBytes-1].  A cursor
** used to incrementally tokenize this string is returned in
** *ppCursor.
*/
static int icuOpen(
  sqlite3_tokenizer *pTokenizer,         /* The tokenizer */
  const char *zInput,                    /* Input string */
  int nInput,                            /* Length of zInput in bytes */
  sqlite3_tokenizer_cursor **ppCursor    /* OUT: Tokenization cursor */
){
  IcuTokenizer *p = (IcuTokenizer *)pTokenizer;
  IcuCursor *pCsr;

  const int32_t opt = U_FOLD_CASE_DEFAULT;
  UErrorCode status = U_ZERO_ERROR;
  int nChar;

  UChar32 c;
  int iInput = 0;
  int iOut = 0;

  *ppCursor = 0;

  if( zInput==0 ){
    nInput = 0;
    zInput = "";
  }else if( nInput<0 ){
    nInput = strlen(zInput);
  }
  nChar = nInput+1;
  pCsr = (IcuCursor *)sqlite3_malloc64(
      sizeof(IcuCursor) +                /* IcuCursor */
      ((nChar+3)&~3) * sizeof(UChar) +   /* IcuCursor.aChar[] */
      (nChar+1) * sizeof(int)            /* IcuCursor.aOffset[] */
  );
  if( !pCsr ){
    return SQLITE_NOMEM;
  }
  memset(pCsr, 0, sizeof(IcuCursor));
  pCsr->aChar = (UChar *)&pCsr[1];
  pCsr->aOffset = (int *)&pCsr->aChar[(nChar+3)&~3];

  pCsr->aOffset[iOut] = iInput;
  U8_NEXT(zInput, iInput, nInput, c);
  while( c>0 ){
    int isError = 0;
    c = u_foldCase(c, opt);
    U16_APPEND(pCsr->aChar, iOut, nChar, c, isError);
    if( isError ){
      sqlite3_free(pCsr);
      return SQLITE_ERROR;
    }
    pCsr->aOffset[iOut] = iInput;

    if( iInput<nInput ){
      U8_NEXT(zInput, iInput, nInput, c);
    }else{
      c = 0;
    }
  }

  pCsr->pIter = ubrk_open(UBRK_WORD, p->zLocale, pCsr->aChar, iOut, &status);
  if( !U_SUCCESS(status) ){
    sqlite3_free(pCsr);
    return SQLITE_ERROR;
  }
  pCsr->nChar = iOut;

  ubrk_first(pCsr->pIter);
  *ppCursor = (sqlite3_tokenizer_cursor *)pCsr;
  return SQLITE_OK;
}

/*
** Close a tokenization cursor previously opened by a call to icuOpen().
*/
static int icuClose(sqlite3_tokenizer_cursor *pCursor){
  IcuCursor *pCsr = (IcuCursor *)pCursor;
  ubrk_close(pCsr->pIter);
  sqlite3_free(pCsr->zBuffer);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

/*
** Extract the next token from a tokenization cursor.
*/
static int icuNext(
  sqlite3_tokenizer_cursor *pCursor,  /* Cursor returned by simpleOpen */
  const char **ppToken,               /* OUT: *ppToken is the token text */
  int *pnBytes,                       /* OUT: Number of bytes in token */
  int *piStartOffset,                 /* OUT: Starting offset of token */
  int *piEndOffset,                   /* OUT: Ending offset of token */
  int *piPosition                     /* OUT: Position integer of token */
){
  IcuCursor *pCsr = (IcuCursor *)pCursor;

  int iStart = 0;
  int iEnd = 0;
  int nByte = 0;

  while( iStart==iEnd ){
    UChar32 c;

    iStart = ubrk_current(pCsr->pIter);
    iEnd = ubrk_next(pCsr->pIter);
    if( iEnd==UBRK_DONE ){
      return SQLITE_DONE;
    }

    while( iStart<iEnd ){
      int iWhite = iStart;
      U16_NEXT(pCsr->aChar, iWhite, pCsr->nChar, c);
      if( u_isspace(c) ){
        iStart = iWhite;
      }else{
        break;
      }
    }
    assert(iStart<=iEnd);
  }

  do {
    UErrorCode status = U_ZERO_ERROR;
    if( nByte ){
      char *zNew = sqlite3_realloc(pCsr->zBuffer, nByte);
      if( !zNew ){
        return SQLITE_NOMEM;
      }
      pCsr->zBuffer = zNew;
      pCsr->nBuffer = nByte;
    }

    u_strToUTF8(
        pCsr->zBuffer, pCsr->nBuffer, &nByte,    /* Output vars */
        &pCsr->aChar[iStart], iEnd-iStart,       /* Input vars */
        &status                                  /* Output success/failure */
    );
  } while( nByte>pCsr->nBuffer );

  *ppToken = pCsr->zBuffer;
  *pnBytes = nByte;
  *piStartOffset = pCsr->aOffset[iStart];
  *piEndOffset = pCsr->aOffset[iEnd];
  *piPosition = pCsr->iToken++;

  return SQLITE_OK;
}

sqlite3.c  view on Meta::CPAN

  if( eType==RBU_DELETE ){
    p->nPhaseOneStep -= p->objiter.nIndex;
  }

  if( eType==RBU_IDX_DELETE || eType==RBU_DELETE ){
    pWriter = pIter->pDelete;
  }else{
    pWriter = pIter->pInsert;
  }

  for(i=0; i<pIter->nCol; i++){
    /* If this is an INSERT into a table b-tree and the table has an
    ** explicit INTEGER PRIMARY KEY, check that this is not an attempt
    ** to write a NULL into the IPK column. That is not permitted.  */
    if( eType==RBU_INSERT
     && pIter->zIdx==0 && pIter->eType==RBU_PK_IPK && pIter->abTblPk[i]
     && sqlite3_column_type(pIter->pSelect, i)==SQLITE_NULL
    ){
      p->rc = SQLITE_MISMATCH;
      p->zErrmsg = sqlite3_mprintf("datatype mismatch");
      return;
    }

    if( eType==RBU_DELETE && pIter->abTblPk[i]==0 ){
      continue;
    }

    pVal = sqlite3_column_value(pIter->pSelect, i);
    p->rc = sqlite3_bind_value(pWriter, i+1, pVal);
    if( p->rc ) return;
  }
  if( pIter->zIdx==0 ){
    if( pIter->eType==RBU_PK_VTAB
     || pIter->eType==RBU_PK_NONE
     || (pIter->eType==RBU_PK_EXTERNAL && rbuIsVacuum(p))
    ){
      /* For a virtual table, or a table with no primary key, the
      ** SELECT statement is:
      **
      **   SELECT <cols>, rbu_control, rbu_rowid FROM ....
      **
      ** Hence column_value(pIter->nCol+1).
      */
      assertColumnName(pIter->pSelect, pIter->nCol+1,
          rbuIsVacuum(p) ? "rowid" : "rbu_rowid"
      );
      pVal = sqlite3_column_value(pIter->pSelect, pIter->nCol+1);
      p->rc = sqlite3_bind_value(pWriter, pIter->nCol+1, pVal);
    }
  }
  if( p->rc==SQLITE_OK ){
    sqlite3_step(pWriter);
    p->rc = resetAndCollectError(pWriter, &p->zErrmsg);
  }
}

/*
** This function does the work for an sqlite3rbu_step() call.
**
** The object-iterator (p->objiter) currently points to a valid object,
** and the input cursor (p->objiter.pSelect) currently points to a valid
** input row. Perform whatever processing is required and return.
**
** If no  error occurs, SQLITE_OK is returned. Otherwise, an error code
** and message is left in the RBU handle and a copy of the error code
** returned.
*/
static int rbuStep(sqlite3rbu *p){
  RbuObjIter *pIter = &p->objiter;
  const char *zMask = 0;
  int eType = rbuStepType(p, &zMask);

  if( eType ){
    assert( eType==RBU_INSERT     || eType==RBU_DELETE
         || eType==RBU_REPLACE    || eType==RBU_IDX_DELETE
         || eType==RBU_IDX_INSERT || eType==RBU_UPDATE
    );
    assert( eType!=RBU_UPDATE || pIter->zIdx==0 );

    if( pIter->zIdx==0 && (eType==RBU_IDX_DELETE || eType==RBU_IDX_INSERT) ){
      rbuBadControlError(p);
    }
    else if( eType==RBU_REPLACE ){
      if( pIter->zIdx==0 ){
        p->nPhaseOneStep += p->objiter.nIndex;
        rbuStepOneOp(p, RBU_DELETE);
      }
      if( p->rc==SQLITE_OK ) rbuStepOneOp(p, RBU_INSERT);
    }
    else if( eType!=RBU_UPDATE ){
      rbuStepOneOp(p, eType);
    }
    else{
      sqlite3_value *pVal;
      sqlite3_stmt *pUpdate = 0;
      assert( eType==RBU_UPDATE );
      p->nPhaseOneStep -= p->objiter.nIndex;
      rbuGetUpdateStmt(p, pIter, zMask, &pUpdate);
      if( pUpdate ){
        int i;
        for(i=0; p->rc==SQLITE_OK && i<pIter->nCol; i++){
          char c = zMask[pIter->aiSrcOrder[i]];
          pVal = sqlite3_column_value(pIter->pSelect, i);
          if( pIter->abTblPk[i] || c!='.' ){
            p->rc = sqlite3_bind_value(pUpdate, i+1, pVal);
          }
        }
        if( p->rc==SQLITE_OK
         && (pIter->eType==RBU_PK_VTAB || pIter->eType==RBU_PK_NONE)
        ){
          /* Bind the rbu_rowid value to column _rowid_ */
          assertColumnName(pIter->pSelect, pIter->nCol+1, "rbu_rowid");
          pVal = sqlite3_column_value(pIter->pSelect, pIter->nCol+1);
          p->rc = sqlite3_bind_value(pUpdate, pIter->nCol+1, pVal);
        }
        if( p->rc==SQLITE_OK ){
          sqlite3_step(pUpdate);
          p->rc = resetAndCollectError(pUpdate, &p->zErrmsg);
        }
      }
    }

sqlite3.c  view on Meta::CPAN

**
**      '/1c2/000+000000'         // First page in overflow chain
**      '/1c2/000+000001'         // Second page in overflow chain
**      '/1c2/000+000002'         // Third page in overflow chain
**
**   If the paths are sorted using the BINARY collation sequence, then
**   the overflow pages associated with a cell will appear earlier in the
**   sort-order than its child page:
**
**      '/1c2/000/'               // Left-most child of 451st child of root
*/
static const char zDbstatSchema[] =
  "CREATE TABLE x("
  " name       TEXT,"          /*  0 Name of table or index */
  " path       TEXT,"          /*  1 Path to page from root (NULL for agg) */
  " pageno     INTEGER,"       /*  2 Page number (page count for aggregates) */
  " pagetype   TEXT,"          /*  3 'internal', 'leaf', 'overflow', or NULL */
  " ncell      INTEGER,"       /*  4 Cells on page (0 for overflow) */
  " payload    INTEGER,"       /*  5 Bytes of payload on this page */
  " unused     INTEGER,"       /*  6 Bytes of unused space on this page */
  " mx_payload INTEGER,"       /*  7 Largest payload size of all cells */
  " pgoffset   INTEGER,"       /*  8 Offset of page in file (NULL for agg) */
  " pgsize     INTEGER,"       /*  9 Size of the page (sum for aggregate) */
  " schema     TEXT HIDDEN,"   /* 10 Database schema being analyzed */
  " aggregate  BOOLEAN HIDDEN" /* 11 aggregate info for each table */
  ")"
;

/* Forward reference to data structured used in this module */
typedef struct StatTable StatTable;
typedef struct StatCursor StatCursor;
typedef struct StatPage StatPage;
typedef struct StatCell StatCell;

/* Size information for a single cell within a btree page */
struct StatCell {
  int nLocal;                     /* Bytes of local payload */
  u32 iChildPg;                   /* Child node (or 0 if this is a leaf) */
  int nOvfl;                      /* Entries in aOvfl[] */
  u32 *aOvfl;                     /* Array of overflow page numbers */
  int nLastOvfl;                  /* Bytes of payload on final overflow page */
  int iOvfl;                      /* Iterates through aOvfl[] */
};

/* Size information for a single btree page */
struct StatPage {
  u32 iPgno;                      /* Page number */
  u8 *aPg;                        /* Page buffer from sqlite3_malloc() */
  int iCell;                      /* Current cell */
  char *zPath;                    /* Path to this page */

  /* Variables populated by statDecodePage(): */
  u8 flags;                       /* Copy of flags byte */
  int nCell;                      /* Number of cells on page */
  int nUnused;                    /* Number of unused bytes on page */
  StatCell *aCell;                /* Array of parsed cells */
  u32 iRightChildPg;              /* Right-child page number (or 0) */
  int nMxPayload;                 /* Largest payload of any cell on the page */
};

/* The cursor for scanning the dbstat virtual table */
struct StatCursor {
  sqlite3_vtab_cursor base;       /* base class.  MUST BE FIRST! */
  sqlite3_stmt *pStmt;            /* Iterates through set of root pages */
  u8 isEof;                       /* After pStmt has returned SQLITE_DONE */
  u8 isAgg;                       /* Aggregate results for each table */
  int iDb;                        /* Schema used for this query */

  StatPage aPage[32];             /* Pages in path to current page */
  int iPage;                      /* Current entry in aPage[] */

  /* Values to return. */
  u32 iPageno;                    /* Value of 'pageno' column */
  char *zName;                    /* Value of 'name' column */
  char *zPath;                    /* Value of 'path' column */
  char *zPagetype;                /* Value of 'pagetype' column */
  int nPage;                      /* Number of pages in current btree */
  int nCell;                      /* Value of 'ncell' column */
  int nMxPayload;                 /* Value of 'mx_payload' column */
  i64 nUnused;                    /* Value of 'unused' column */
  i64 nPayload;                   /* Value of 'payload' column */
  i64 iOffset;                    /* Value of 'pgOffset' column */
  i64 szPage;                     /* Value of 'pgSize' column */
};

/* An instance of the DBSTAT virtual table */
struct StatTable {
  sqlite3_vtab base;              /* base class.  MUST BE FIRST! */
  sqlite3 *db;                    /* Database connection that owns this vtab */
  int iDb;                        /* Index of database to analyze */
};

#ifndef get2byte
# define get2byte(x)   ((x)[0]<<8 | (x)[1])
#endif

/*
** Connect to or create a new DBSTAT virtual table.
*/
static int statConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  StatTable *pTab = 0;
  int rc = SQLITE_OK;
  int iDb;
  (void)pAux;

  if( argc>=4 ){
    Token nm;
    sqlite3TokenInit(&nm, (char*)argv[3]);
    iDb = sqlite3FindDb(db, &nm);
    if( iDb<0 ){
      *pzErr = sqlite3_mprintf("no such database: %s", argv[3]);
      return SQLITE_ERROR;
    }
  }else{
    iDb = 0;
  }
  sqlite3_vtab_config(db, SQLITE_VTAB_DIRECTONLY);

sqlite3.c  view on Meta::CPAN

    if( pIdxInfo->aConstraint[i].op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
    if( pIdxInfo->aConstraint[i].usable==0 ){
      /* Force DBSTAT table should always be the right-most table in a join */
      return SQLITE_CONSTRAINT;
    }
    switch( pIdxInfo->aConstraint[i].iColumn ){
      case 0: {    /* name */
        iName = i;
        break;
      }
      case 10: {   /* schema */
        iSchema = i;
        break;
      }
      case 11: {   /* aggregate */
        iAgg = i;
        break;
      }
    }
  }
  i = 0;
  if( iSchema>=0 ){
    pIdxInfo->aConstraintUsage[iSchema].argvIndex = ++i;
    pIdxInfo->aConstraintUsage[iSchema].omit = 1;
    pIdxInfo->idxNum |= 0x01;
  }
  if( iName>=0 ){
    pIdxInfo->aConstraintUsage[iName].argvIndex = ++i;
    pIdxInfo->idxNum |= 0x02;
  }
  if( iAgg>=0 ){
    pIdxInfo->aConstraintUsage[iAgg].argvIndex = ++i;
    pIdxInfo->idxNum |= 0x04;
  }
  pIdxInfo->estimatedCost = 1.0;

  /* Records are always returned in ascending order of (name, path).
  ** If this will satisfy the client, set the orderByConsumed flag so that
  ** SQLite does not do an external sort.
  */
  if( ( pIdxInfo->nOrderBy==1
     && pIdxInfo->aOrderBy[0].iColumn==0
     && pIdxInfo->aOrderBy[0].desc==0
     ) ||
      ( pIdxInfo->nOrderBy==2
     && pIdxInfo->aOrderBy[0].iColumn==0
     && pIdxInfo->aOrderBy[0].desc==0
     && pIdxInfo->aOrderBy[1].iColumn==1
     && pIdxInfo->aOrderBy[1].desc==0
     )
  ){
    pIdxInfo->orderByConsumed = 1;
    pIdxInfo->idxNum |= 0x08;
  }
  pIdxInfo->idxFlags |= SQLITE_INDEX_SCAN_HEX;

  return SQLITE_OK;
}

/*
** Open a new DBSTAT cursor.
*/
static int statOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
  StatTable *pTab = (StatTable *)pVTab;
  StatCursor *pCsr;

  pCsr = (StatCursor *)sqlite3_malloc64(sizeof(StatCursor));
  if( pCsr==0 ){
    return SQLITE_NOMEM_BKPT;
  }else{
    memset(pCsr, 0, sizeof(StatCursor));
    pCsr->base.pVtab = pVTab;
    pCsr->iDb = pTab->iDb;
  }

  *ppCursor = (sqlite3_vtab_cursor *)pCsr;
  return SQLITE_OK;
}

static void statClearCells(StatPage *p){
  int i;
  if( p->aCell ){
    for(i=0; i<p->nCell; i++){
      sqlite3_free(p->aCell[i].aOvfl);
    }
    sqlite3_free(p->aCell);
  }
  p->nCell = 0;
  p->aCell = 0;
}

static void statClearPage(StatPage *p){
  u8 *aPg = p->aPg;
  statClearCells(p);
  sqlite3_free(p->zPath);
  memset(p, 0, sizeof(StatPage));
  p->aPg = aPg;
}

static void statResetCsr(StatCursor *pCsr){
  int i;
  /* In some circumstances, specifically if an OOM has occurred, the call
  ** to sqlite3_reset() may cause the pager to be reset (emptied). It is
  ** important that statClearPage() is called to free any page refs before
  ** this happens. dbsqlfuzz 9ed3e4e3816219d3509d711636c38542bf3f40b1. */
  for(i=0; i<ArraySize(pCsr->aPage); i++){
    statClearPage(&pCsr->aPage[i]);
    sqlite3_free(pCsr->aPage[i].aPg);
    pCsr->aPage[i].aPg = 0;
  }
  sqlite3_reset(pCsr->pStmt);
  pCsr->iPage = 0;
  sqlite3_free(pCsr->zPath);
  pCsr->zPath = 0;
  pCsr->isEof = 0;
}

/* Resize the space-used counters inside of the cursor */
static void statResetCounts(StatCursor *pCsr){
  pCsr->nCell = 0;
  pCsr->nMxPayload = 0;
  pCsr->nUnused = 0;
  pCsr->nPayload = 0;
  pCsr->szPage = 0;
  pCsr->nPage = 0;
}

/*
** Close a DBSTAT cursor.
*/
static int statClose(sqlite3_vtab_cursor *pCursor){
  StatCursor *pCsr = (StatCursor *)pCursor;
  statResetCsr(pCsr);
  sqlite3_finalize(pCsr->pStmt);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

/*
** For a single cell on a btree page, compute the number of bytes of
** content (payload) stored on that page.  That is to say, compute the
** number of bytes of content not found on overflow pages.
*/
static int getLocalPayload(
  int nUsable,                    /* Usable bytes per page */
  u8 flags,                       /* Page flags */
  int nTotal                      /* Total record (payload) size */
){
  int nLocal;
  int nMinLocal;
  int nMaxLocal;

  if( flags==0x0D ){              /* Table leaf node */
    nMinLocal = (nUsable - 12) * 32 / 255 - 23;
    nMaxLocal = nUsable - 35;
  }else{                          /* Index interior and leaf nodes */
    nMinLocal = (nUsable - 12) * 32 / 255 - 23;
    nMaxLocal = (nUsable - 12) * 64 / 255 - 23;
  }

  nLocal = nMinLocal + (nTotal - nMinLocal) % (nUsable - 4);
  if( nLocal>nMaxLocal ) nLocal = nMinLocal;
  return nLocal;
}

/* Populate the StatPage object with information about the all
** cells found on the page currently under analysis.
*/
static int statDecodePage(Btree *pBt, StatPage *p){
  int nUnused;
  int iOff;
  int nHdr;
  int isLeaf;
  int szPage;

  u8 *aData = p->aPg;
  u8 *aHdr = &aData[p->iPgno==1 ? 100 : 0];

  p->flags = aHdr[0];
  if( p->flags==0x0A || p->flags==0x0D ){
    isLeaf = 1;
    nHdr = 8;
  }else if( p->flags==0x05 || p->flags==0x02 ){
    isLeaf = 0;
    nHdr = 12;
  }else{
    goto statPageIsCorrupt;
  }
  if( p->iPgno==1 ) nHdr += 100;
  p->nCell = get2byte(&aHdr[3]);
  p->nMxPayload = 0;

sqlite3.c  view on Meta::CPAN

        pCell->iChildPg = sqlite3Get4byte(&aData[iOff]);
        iOff += 4;
      }
      if( p->flags==0x05 ){
        /* A table interior node. nPayload==0. */
      }else{
        u32 nPayload;             /* Bytes of payload total (local+overflow) */
        int nLocal;               /* Bytes of payload stored locally */
        iOff += getVarint32(&aData[iOff], nPayload);
        if( p->flags==0x0D ){
          u64 dummy;
          iOff += sqlite3GetVarint(&aData[iOff], &dummy);
        }
        if( nPayload>(u32)p->nMxPayload ) p->nMxPayload = nPayload;
        nLocal = getLocalPayload(nUsable, p->flags, nPayload);
        if( nLocal<0 ) goto statPageIsCorrupt;
        pCell->nLocal = nLocal;
        assert( nPayload>=(u32)nLocal );
        assert( nLocal<=(nUsable-35) );
        if( nPayload>(u32)nLocal ){
          int j;
          int nOvfl = ((nPayload - nLocal) + nUsable-4 - 1) / (nUsable - 4);
          if( iOff+nLocal+4>nUsable || nPayload>0x7fffffff ){
            goto statPageIsCorrupt;
          }
          pCell->nLastOvfl = (nPayload-nLocal) - (nOvfl-1) * (nUsable-4);
          pCell->nOvfl = nOvfl;
          pCell->aOvfl = sqlite3_malloc64(sizeof(u32)*nOvfl);
          if( pCell->aOvfl==0 ) return SQLITE_NOMEM_BKPT;
          pCell->aOvfl[0] = sqlite3Get4byte(&aData[iOff+nLocal]);
          for(j=1; j<nOvfl; j++){
            int rc;
            u32 iPrev = pCell->aOvfl[j-1];
            DbPage *pPg = 0;
            rc = sqlite3PagerGet(sqlite3BtreePager(pBt), iPrev, &pPg, 0);
            if( rc!=SQLITE_OK ){
              assert( pPg==0 );
              return rc;
            }
            pCell->aOvfl[j] = sqlite3Get4byte(sqlite3PagerGetData(pPg));
            sqlite3PagerUnref(pPg);
          }
        }
      }
    }
  }

  return SQLITE_OK;

statPageIsCorrupt:
  p->flags = 0;
  statClearCells(p);
  return SQLITE_OK;
}

/*
** Populate the pCsr->iOffset and pCsr->szPage member variables. Based on
** the current value of pCsr->iPageno.
*/
static void statSizeAndOffset(StatCursor *pCsr){
  StatTable *pTab = (StatTable *)((sqlite3_vtab_cursor *)pCsr)->pVtab;
  Btree *pBt = pTab->db->aDb[pTab->iDb].pBt;
  Pager *pPager = sqlite3BtreePager(pBt);
  sqlite3_file *fd;
  sqlite3_int64 x[2];

  /* If connected to a ZIPVFS backend, find the page size and
  ** offset from ZIPVFS.
  */
  fd = sqlite3PagerFile(pPager);
  x[0] = pCsr->iPageno;
  if( sqlite3OsFileControl(fd, 230440, &x)==SQLITE_OK ){
    pCsr->iOffset = x[0];
    pCsr->szPage += x[1];
  }else{
    /* Not ZIPVFS: The default page size and offset */
    pCsr->szPage += sqlite3BtreeGetPageSize(pBt);
    pCsr->iOffset = (i64)pCsr->szPage * (pCsr->iPageno - 1);
  }
}

/*
** Load a copy of the page data for page iPg into the buffer belonging
** to page object pPg. Allocate the buffer if necessary. Return SQLITE_OK
** if successful, or an SQLite error code otherwise.
*/
static int statGetPage(
  Btree *pBt,                     /* Load page from this b-tree */
  u32 iPg,                        /* Page number to load */
  StatPage *pPg                   /* Load page into this object */
){
  int pgsz = sqlite3BtreeGetPageSize(pBt);
  DbPage *pDbPage = 0;
  int rc;

  if( pPg->aPg==0 ){
    pPg->aPg = (u8*)sqlite3_malloc(pgsz + DBSTAT_PAGE_PADDING_BYTES);
    if( pPg->aPg==0 ){
      return SQLITE_NOMEM_BKPT;
    }
    memset(&pPg->aPg[pgsz], 0, DBSTAT_PAGE_PADDING_BYTES);
  }

  rc = sqlite3PagerGet(sqlite3BtreePager(pBt), iPg, &pDbPage, 0);
  if( rc==SQLITE_OK ){
    const u8 *a = sqlite3PagerGetData(pDbPage);
    memcpy(pPg->aPg, a, pgsz);
    sqlite3PagerUnref(pDbPage);
  }

  return rc;
}

/*
** Move a DBSTAT cursor to the next entry.  Normally, the next
** entry will be the next page, but in aggregated mode (pCsr->isAgg!=0),
** the next entry is the next btree.
*/
static int statNext(sqlite3_vtab_cursor *pCursor){
  int rc;
  int nPayload;
  char *z;
  StatCursor *pCsr = (StatCursor *)pCursor;
  StatTable *pTab = (StatTable *)pCursor->pVtab;
  Btree *pBt = pTab->db->aDb[pCsr->iDb].pBt;
  Pager *pPager = sqlite3BtreePager(pBt);

  sqlite3_free(pCsr->zPath);
  pCsr->zPath = 0;

statNextRestart:
  if( pCsr->iPage<0 ){
    /* Start measuring space on the next btree */
    statResetCounts(pCsr);
    rc = sqlite3_step(pCsr->pStmt);
    if( rc==SQLITE_ROW ){
      int nPage;
      u32 iRoot = (u32)sqlite3_column_int64(pCsr->pStmt, 1);
      sqlite3PagerPagecount(pPager, &nPage);
      if( nPage==0 ){
        pCsr->isEof = 1;
        return sqlite3_reset(pCsr->pStmt);
      }
      rc = statGetPage(pBt, iRoot, &pCsr->aPage[0]);
      pCsr->aPage[0].iPgno = iRoot;
      pCsr->aPage[0].iCell = 0;
      if( !pCsr->isAgg ){
        pCsr->aPage[0].zPath = z = sqlite3_mprintf("/");
        if( z==0 ) rc = SQLITE_NOMEM_BKPT;
      }
      pCsr->iPage = 0;
      pCsr->nPage = 1;
    }else{
      pCsr->isEof = 1;
      return sqlite3_reset(pCsr->pStmt);
    }
  }else{
    /* Continue analyzing the btree previously started */
    StatPage *p = &pCsr->aPage[pCsr->iPage];
    if( !pCsr->isAgg ) statResetCounts(pCsr);
    while( p->iCell<p->nCell ){
      StatCell *pCell = &p->aCell[p->iCell];
      while( pCell->iOvfl<pCell->nOvfl ){
        int nUsable, iOvfl;
        sqlite3BtreeEnter(pBt);
        nUsable = sqlite3BtreeGetPageSize(pBt) -
                        sqlite3BtreeGetReserveNoMutex(pBt);
        sqlite3BtreeLeave(pBt);
        pCsr->nPage++;
        statSizeAndOffset(pCsr);
        if( pCell->iOvfl<pCell->nOvfl-1 ){
          pCsr->nPayload += nUsable - 4;
        }else{
          pCsr->nPayload += pCell->nLastOvfl;
          pCsr->nUnused += nUsable - 4 - pCell->nLastOvfl;
        }
        iOvfl = pCell->iOvfl;
        pCell->iOvfl++;
        if( !pCsr->isAgg ){

sqlite3.c  view on Meta::CPAN

    rc = statGetPage(pBt, p[1].iPgno, &p[1]);
    pCsr->nPage++;
    p[1].iCell = 0;
    if( !pCsr->isAgg ){
      p[1].zPath = z = sqlite3_mprintf("%s%.3x/", p->zPath, p->iCell);
      if( z==0 ) rc = SQLITE_NOMEM_BKPT;
    }
    p->iCell++;
  }


  /* Populate the StatCursor fields with the values to be returned
  ** by the xColumn() and xRowid() methods.
  */
  if( rc==SQLITE_OK ){
    int i;
    StatPage *p = &pCsr->aPage[pCsr->iPage];
    pCsr->zName = (char *)sqlite3_column_text(pCsr->pStmt, 0);
    pCsr->iPageno = p->iPgno;

    rc = statDecodePage(pBt, p);
    if( rc==SQLITE_OK ){
      statSizeAndOffset(pCsr);

      switch( p->flags ){
        case 0x05:             /* table internal */
        case 0x02:             /* index internal */
          pCsr->zPagetype = "internal";
          break;
        case 0x0D:             /* table leaf */
        case 0x0A:             /* index leaf */
          pCsr->zPagetype = "leaf";
          break;
        default:
          pCsr->zPagetype = "corrupted";
          break;
      }
      pCsr->nCell += p->nCell;
      pCsr->nUnused += p->nUnused;
      if( p->nMxPayload>pCsr->nMxPayload ) pCsr->nMxPayload = p->nMxPayload;
      if( !pCsr->isAgg ){
        pCsr->zPath = z = sqlite3_mprintf("%s", p->zPath);
        if( z==0 ) rc = SQLITE_NOMEM_BKPT;
      }
      nPayload = 0;
      for(i=0; i<p->nCell; i++){
        nPayload += p->aCell[i].nLocal;
      }
      pCsr->nPayload += nPayload;

      /* If computing aggregate space usage by btree, continue with the
      ** next page.  The loop will exit via the return at label-statNext-done
      */
      if( pCsr->isAgg ) goto statNextRestart;
    }
  }

  return rc;
}

static int statEof(sqlite3_vtab_cursor *pCursor){
  StatCursor *pCsr = (StatCursor *)pCursor;
  return pCsr->isEof;
}

/* Initialize a cursor according to the query plan idxNum using the
** arguments in argv[0].  See statBestIndex() for a description of the
** meaning of the bits in idxNum.
*/
static int statFilter(
  sqlite3_vtab_cursor *pCursor,
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  StatCursor *pCsr = (StatCursor *)pCursor;
  StatTable *pTab = (StatTable*)(pCursor->pVtab);
  sqlite3_str *pSql;      /* Query of btrees to analyze */
  char *zSql;             /* String value of pSql */
  int iArg = 0;           /* Count of argv[] parameters used so far */
  int rc = SQLITE_OK;     /* Result of this operation */
  const char *zName = 0;  /* Only provide analysis of this table */
  (void)argc;
  (void)idxStr;

  statResetCsr(pCsr);
  sqlite3_finalize(pCsr->pStmt);
  pCsr->pStmt = 0;
  if( idxNum & 0x01 ){
    /* schema=? constraint is present.  Get its value */
    const char *zDbase = (const char*)sqlite3_value_text(argv[iArg++]);
    pCsr->iDb = sqlite3FindDbName(pTab->db, zDbase);
    if( pCsr->iDb<0 ){
      pCsr->iDb = 0;
      pCsr->isEof = 1;
      return SQLITE_OK;
    }
  }else{
    pCsr->iDb = pTab->iDb;
  }
  if( idxNum & 0x02 ){
    /* name=? constraint is present */
    zName = (const char*)sqlite3_value_text(argv[iArg++]);
  }
  if( idxNum & 0x04 ){
    /* aggregate=? constraint is present */
    pCsr->isAgg = sqlite3_value_double(argv[iArg++])!=0.0;
  }else{
    pCsr->isAgg = 0;
  }
  pSql = sqlite3_str_new(pTab->db);
  sqlite3_str_appendf(pSql,
      "SELECT * FROM ("
        "SELECT 'sqlite_schema' AS name,1 AS rootpage,'table' AS type"
        " UNION ALL "
        "SELECT name,rootpage,type"
        " FROM \"%w\".sqlite_schema WHERE rootpage!=0)",
      pTab->db->aDb[pCsr->iDb].zDbSName);
  if( zName ){
    sqlite3_str_appendf(pSql, "WHERE name=%Q", zName);
  }
  if( idxNum & 0x08 ){
    sqlite3_str_appendf(pSql, " ORDER BY name");
  }
  zSql = sqlite3_str_finish(pSql);
  if( zSql==0 ){
    return SQLITE_NOMEM_BKPT;
  }else{
    rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pCsr->pStmt, 0);
    sqlite3_free(zSql);
  }

  if( rc==SQLITE_OK ){
    pCsr->iPage = -1;
    rc = statNext(pCursor);
  }
  return rc;
}

static int statColumn(
  sqlite3_vtab_cursor *pCursor,
  sqlite3_context *ctx,
  int i
){
  StatCursor *pCsr = (StatCursor *)pCursor;
  switch( i ){
    case 0:            /* name */
      sqlite3_result_text(ctx, pCsr->zName, -1, SQLITE_TRANSIENT);
      break;
    case 1:            /* path */
      if( !pCsr->isAgg ){
        sqlite3_result_text(ctx, pCsr->zPath, -1, SQLITE_TRANSIENT);
      }
      break;
    case 2:            /* pageno */
      if( pCsr->isAgg ){
        sqlite3_result_int64(ctx, pCsr->nPage);
      }else{
        sqlite3_result_int64(ctx, pCsr->iPageno);
      }
      break;
    case 3:            /* pagetype */
      if( !pCsr->isAgg ){
        sqlite3_result_text(ctx, pCsr->zPagetype, -1, SQLITE_STATIC);
      }
      break;
    case 4:            /* ncell */
      sqlite3_result_int64(ctx, pCsr->nCell);
      break;
    case 5:            /* payload */
      sqlite3_result_int64(ctx, pCsr->nPayload);
      break;
    case 6:            /* unused */
      sqlite3_result_int64(ctx, pCsr->nUnused);
      break;
    case 7:            /* mx_payload */
      sqlite3_result_int64(ctx, pCsr->nMxPayload);
      break;
    case 8:            /* pgoffset */
      if( !pCsr->isAgg ){
        sqlite3_result_int64(ctx, pCsr->iOffset);
      }
      break;
    case 9:            /* pgsize */
      sqlite3_result_int64(ctx, pCsr->szPage);
      break;
    case 10: {         /* schema */
      sqlite3 *db = sqlite3_context_db_handle(ctx);
      int iDb = pCsr->iDb;
      sqlite3_result_text(ctx, db->aDb[iDb].zDbSName, -1, SQLITE_STATIC);
      break;
    }
    default: {         /* aggregate */
      sqlite3_result_int(ctx, pCsr->isAgg);
      break;
    }
  }
  return SQLITE_OK;
}

static int statRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
  StatCursor *pCsr = (StatCursor *)pCursor;
  *pRowid = pCsr->iPageno;
  return SQLITE_OK;
}

/*
** Invoke this routine to register the "dbstat" virtual table module
*/
SQLITE_PRIVATE int sqlite3DbstatRegister(sqlite3 *db){
  static sqlite3_module dbstat_module = {
    0,                            /* iVersion */
    statConnect,                  /* xCreate */
    statConnect,                  /* xConnect */
    statBestIndex,                /* xBestIndex */
    statDisconnect,               /* xDisconnect */
    statDisconnect,               /* xDestroy */
    statOpen,                     /* xOpen - open a cursor */
    statClose,                    /* xClose - close a cursor */
    statFilter,                   /* xFilter - configure scan constraints */
    statNext,                     /* xNext - advance a cursor */
    statEof,                      /* xEof - check for end of scan */
    statColumn,                   /* xColumn - read data */
    statRowid,                    /* xRowid - read data */
    0,                            /* xUpdate */
    0,                            /* xBegin */
    0,                            /* xSync */
    0,                            /* xCommit */
    0,                            /* xRollback */
    0,                            /* xFindMethod */
    0,                            /* xRename */
    0,                            /* xSavepoint */
    0,                            /* xRelease */
    0,                            /* xRollbackTo */
    0,                            /* xShadowName */
    0                             /* xIntegrity */
  };
  return sqlite3_create_module(db, "dbstat", &dbstat_module, 0);
}
#elif defined(SQLITE_ENABLE_DBSTAT_VTAB)
SQLITE_PRIVATE int sqlite3DbstatRegister(sqlite3 *db){ return SQLITE_OK; }
#endif /* SQLITE_ENABLE_DBSTAT_VTAB */

/************** End of dbstat.c **********************************************/
/************** Begin file dbpage.c ******************************************/
/*
** 2017-10-11
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file contains an implementation of the "sqlite_dbpage" virtual table.
**
** The sqlite_dbpage virtual table is used to read or write whole raw
** pages of the database file.  The pager interface is used so that
** uncommitted changes and changes recorded in the WAL file are correctly
** retrieved.
**
** Usage example:
**
**    SELECT data FROM sqlite_dbpage('aux1') WHERE pgno=123;
**
** This is an eponymous virtual table so it does not need to be created before
** use.  The optional argument to the sqlite_dbpage() table name is the
** schema for the database file that is to be read.  The default schema is
** "main".
**
** The data field of sqlite_dbpage table can be updated.  The new
** value must be a BLOB which is the correct page size, otherwise the
** update fails.  INSERT operations also work, and operate as if they
** where REPLACE.  The size of the database can be extended by INSERT-ing
** new pages on the end.
**
** Rows may not be deleted.  However, doing an INSERT to page number N
** with NULL page data causes the N-th page and all subsequent pages to be
** deleted and the database to be truncated.
*/

/* #include "sqliteInt.h"   ** Requires access to internal data structures ** */
#if (defined(SQLITE_ENABLE_DBPAGE_VTAB) || defined(SQLITE_TEST)) \
    && !defined(SQLITE_OMIT_VIRTUALTABLE)

typedef struct DbpageTable DbpageTable;
typedef struct DbpageCursor DbpageCursor;

struct DbpageCursor {
  sqlite3_vtab_cursor base;       /* Base class.  Must be first */
  Pgno pgno;                      /* Current page number */
  Pgno mxPgno;                    /* Last page to visit on this scan */
  Pager *pPager;                  /* Pager being read/written */
  DbPage *pPage1;                 /* Page 1 of the database */
  int iDb;                        /* Index of database to analyze */
  int szPage;                     /* Size of each page in bytes */
};

struct DbpageTable {
  sqlite3_vtab base;              /* Base class.  Must be first */
  sqlite3 *db;                    /* The database */
  int iDbTrunc;                   /* Database to truncate */
  Pgno pgnoTrunc;                 /* Size to truncate to */
};

/* Columns */
#define DBPAGE_COLUMN_PGNO    0
#define DBPAGE_COLUMN_DATA    1
#define DBPAGE_COLUMN_SCHEMA  2


/*
** Connect to or create a dbpagevfs virtual table.
*/
static int dbpageConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  DbpageTable *pTab = 0;
  int rc = SQLITE_OK;
  (void)pAux;
  (void)argc;
  (void)argv;
  (void)pzErr;

  sqlite3_vtab_config(db, SQLITE_VTAB_DIRECTONLY);
  sqlite3_vtab_config(db, SQLITE_VTAB_USES_ALL_SCHEMAS);
  rc = sqlite3_declare_vtab(db,
          "CREATE TABLE x(pgno INTEGER PRIMARY KEY, data BLOB, schema HIDDEN)");
  if( rc==SQLITE_OK ){
    pTab = (DbpageTable *)sqlite3_malloc64(sizeof(DbpageTable));
    if( pTab==0 ) rc = SQLITE_NOMEM_BKPT;
  }

  assert( rc==SQLITE_OK || pTab==0 );
  if( rc==SQLITE_OK ){
    memset(pTab, 0, sizeof(DbpageTable));
    pTab->db = db;
  }

  *ppVtab = (sqlite3_vtab*)pTab;
  return rc;
}

/*
** Disconnect from or destroy a dbpagevfs virtual table.
*/

sqlite3.c  view on Meta::CPAN

**
**     0     schema=main, full table scan
**     1     schema=main, pgno=?1
**     2     schema=?1, full table scan
**     3     schema=?1, pgno=?2
*/
static int dbpageBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
  int i;
  int iPlan = 0;
  (void)tab;

  /* If there is a schema= constraint, it must be honored.  Report a
  ** ridiculously large estimated cost if the schema= constraint is
  ** unavailable
  */
  for(i=0; i<pIdxInfo->nConstraint; i++){
    struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[i];
    if( p->iColumn!=DBPAGE_COLUMN_SCHEMA ) continue;
    if( p->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
    if( !p->usable ){
      /* No solution. */
      return SQLITE_CONSTRAINT;
    }
    iPlan = 2;
    pIdxInfo->aConstraintUsage[i].argvIndex = 1;
    pIdxInfo->aConstraintUsage[i].omit = 1;
    break;
  }

  /* If we reach this point, it means that either there is no schema=
  ** constraint (in which case we use the "main" schema) or else the
  ** schema constraint was accepted.  Lower the estimated cost accordingly
  */
  pIdxInfo->estimatedCost = 1.0e6;

  /* Check for constraints against pgno */
  for(i=0; i<pIdxInfo->nConstraint; i++){
    struct sqlite3_index_constraint *p = &pIdxInfo->aConstraint[i];
    if( p->usable && p->iColumn<=0 && p->op==SQLITE_INDEX_CONSTRAINT_EQ ){
      pIdxInfo->estimatedRows = 1;
      pIdxInfo->idxFlags = SQLITE_INDEX_SCAN_UNIQUE;
      pIdxInfo->estimatedCost = 1.0;
      pIdxInfo->aConstraintUsage[i].argvIndex = iPlan ? 2 : 1;
      pIdxInfo->aConstraintUsage[i].omit = 1;
      iPlan |= 1;
      break;
    }
  }
  pIdxInfo->idxNum = iPlan;

  if( pIdxInfo->nOrderBy>=1
   && pIdxInfo->aOrderBy[0].iColumn<=0
   && pIdxInfo->aOrderBy[0].desc==0
  ){
    pIdxInfo->orderByConsumed = 1;
  }
  return SQLITE_OK;
}

/*
** Open a new dbpagevfs cursor.
*/
static int dbpageOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
  DbpageCursor *pCsr;

  pCsr = (DbpageCursor *)sqlite3_malloc64(sizeof(DbpageCursor));
  if( pCsr==0 ){
    return SQLITE_NOMEM_BKPT;
  }else{
    memset(pCsr, 0, sizeof(DbpageCursor));
    pCsr->base.pVtab = pVTab;
    pCsr->pgno = 0;
  }

  *ppCursor = (sqlite3_vtab_cursor *)pCsr;
  return SQLITE_OK;
}

/*
** Close a dbpagevfs cursor.
*/
static int dbpageClose(sqlite3_vtab_cursor *pCursor){
  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
  if( pCsr->pPage1 ) sqlite3PagerUnrefPageOne(pCsr->pPage1);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

/*
** Move a dbpagevfs cursor to the next entry in the file.
*/
static int dbpageNext(sqlite3_vtab_cursor *pCursor){
  int rc = SQLITE_OK;
  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
  pCsr->pgno++;
  return rc;
}

static int dbpageEof(sqlite3_vtab_cursor *pCursor){
  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
  return pCsr->pgno > pCsr->mxPgno;
}

/*
** idxNum:
**
**     0     schema=main, full table scan
**     1     schema=main, pgno=?1
**     2     schema=?1, full table scan
**     3     schema=?1, pgno=?2
**
** idxStr is not used
*/
static int dbpageFilter(
  sqlite3_vtab_cursor *pCursor,
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
  DbpageTable *pTab = (DbpageTable *)pCursor->pVtab;
  int rc;
  sqlite3 *db = pTab->db;
  Btree *pBt;

  UNUSED_PARAMETER(idxStr);
  UNUSED_PARAMETER(argc);

  /* Default setting is no rows of result */
  pCsr->pgno = 1;
  pCsr->mxPgno = 0;

  if( idxNum & 2 ){
    const char *zSchema;
    assert( argc>=1 );
    zSchema = (const char*)sqlite3_value_text(argv[0]);
    pCsr->iDb = sqlite3FindDbName(db, zSchema);
    if( pCsr->iDb<0 ) return SQLITE_OK;
  }else{
    pCsr->iDb = 0;
  }
  pBt = db->aDb[pCsr->iDb].pBt;
  if( NEVER(pBt==0) ) return SQLITE_OK;
  pCsr->pPager = sqlite3BtreePager(pBt);
  pCsr->szPage = sqlite3BtreeGetPageSize(pBt);
  pCsr->mxPgno = sqlite3BtreeLastPage(pBt);
  if( idxNum & 1 ){
    assert( argc>(idxNum>>1) );
    pCsr->pgno = sqlite3_value_int(argv[idxNum>>1]);
    if( pCsr->pgno<1 || pCsr->pgno>pCsr->mxPgno ){
      pCsr->pgno = 1;
      pCsr->mxPgno = 0;
    }else{
      pCsr->mxPgno = pCsr->pgno;
    }
  }else{
    assert( pCsr->pgno==1 );
  }
  if( pCsr->pPage1 ) sqlite3PagerUnrefPageOne(pCsr->pPage1);
  rc = sqlite3PagerGet(pCsr->pPager, 1, &pCsr->pPage1, 0);
  return rc;
}

static int dbpageColumn(
  sqlite3_vtab_cursor *pCursor,
  sqlite3_context *ctx,
  int i
){
  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
  int rc = SQLITE_OK;
  switch( i ){
    case 0: {           /* pgno */
      sqlite3_result_int64(ctx, (sqlite3_int64)pCsr->pgno);
      break;
    }
    case 1: {           /* data */
      DbPage *pDbPage = 0;
      if( pCsr->pgno==(Pgno)((PENDING_BYTE/pCsr->szPage)+1) ){
        /* The pending byte page. Assume it is zeroed out. Attempting to
        ** request this page from the page is an SQLITE_CORRUPT error. */
        sqlite3_result_zeroblob(ctx, pCsr->szPage);
      }else{
        rc = sqlite3PagerGet(pCsr->pPager, pCsr->pgno, (DbPage**)&pDbPage, 0);
        if( rc==SQLITE_OK ){
          sqlite3_result_blob(ctx, sqlite3PagerGetData(pDbPage), pCsr->szPage,
              SQLITE_TRANSIENT);
        }
        sqlite3PagerUnref(pDbPage);
      }
      break;
    }
    default: {          /* schema */
      sqlite3 *db = sqlite3_context_db_handle(ctx);
      sqlite3_result_text(ctx, db->aDb[pCsr->iDb].zDbSName, -1, SQLITE_STATIC);
      break;
    }
  }
  return rc;
}

static int dbpageRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
  DbpageCursor *pCsr = (DbpageCursor *)pCursor;
  *pRowid = pCsr->pgno;
  return SQLITE_OK;
}

/*
** Open write transactions. Since we do not know in advance which database
** files will be written by the sqlite_dbpage virtual table, start a write
** transaction on them all.
**
** Return SQLITE_OK if successful, or an SQLite error code otherwise.
*/
static int dbpageBeginTrans(DbpageTable *pTab){
  sqlite3 *db = pTab->db;
  int rc = SQLITE_OK;
  int i;
  for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
    Btree *pBt = db->aDb[i].pBt;
    if( pBt ) rc = sqlite3BtreeBeginTrans(pBt, 1, 0);
  }
  return rc;
}

static int dbpageUpdate(
  sqlite3_vtab *pVtab,
  int argc,
  sqlite3_value **argv,
  sqlite_int64 *pRowid
){
  DbpageTable *pTab = (DbpageTable *)pVtab;
  Pgno pgno;
  DbPage *pDbPage = 0;
  int rc = SQLITE_OK;
  char *zErr = 0;
  int iDb;
  Btree *pBt;
  Pager *pPager;
  int szPage;
  int isInsert;

  (void)pRowid;
  if( pTab->db->flags & SQLITE_Defensive ){
    zErr = "read-only";
    goto update_fail;
  }
  if( argc==1 ){
    zErr = "cannot delete";
    goto update_fail;
  }
  if( sqlite3_value_type(argv[0])==SQLITE_NULL ){
    pgno = (Pgno)sqlite3_value_int64(argv[2]);
    isInsert = 1;
  }else{
    pgno = (Pgno)sqlite3_value_int64(argv[0]);
    if( (Pgno)sqlite3_value_int(argv[1])!=pgno ){
      zErr = "cannot insert";
      goto update_fail;
    }
    isInsert = 0;
  }

sqlite3.c  view on Meta::CPAN

      memcpy(aPage, pData, szPage);
      pTab->pgnoTrunc = 0;
    }
  }
  if( rc!=SQLITE_OK ){
    pTab->pgnoTrunc = 0;
  }
  sqlite3PagerUnref(pDbPage);
  return rc;

update_fail:
  pTab->pgnoTrunc = 0;
  sqlite3_free(pVtab->zErrMsg);
  pVtab->zErrMsg = sqlite3_mprintf("%s", zErr);
  return SQLITE_ERROR;
}

static int dbpageBegin(sqlite3_vtab *pVtab){
  DbpageTable *pTab = (DbpageTable *)pVtab;
  pTab->pgnoTrunc = 0;
  return SQLITE_OK;
}

/* Invoke sqlite3PagerTruncate() as necessary, just prior to COMMIT
*/
static int dbpageSync(sqlite3_vtab *pVtab){
  DbpageTable *pTab = (DbpageTable *)pVtab;
  if( pTab->pgnoTrunc>0 ){
    Btree *pBt = pTab->db->aDb[pTab->iDbTrunc].pBt;
    Pager *pPager = sqlite3BtreePager(pBt);
    sqlite3BtreeEnter(pBt);
    if( pTab->pgnoTrunc<sqlite3BtreeLastPage(pBt) ){
      sqlite3PagerTruncateImage(pPager, pTab->pgnoTrunc);
    }
    sqlite3BtreeLeave(pBt);
  }
  pTab->pgnoTrunc = 0;
  return SQLITE_OK;
}

/* Cancel any pending truncate.
*/
static int dbpageRollbackTo(sqlite3_vtab *pVtab, int notUsed1){
  DbpageTable *pTab = (DbpageTable *)pVtab;
  pTab->pgnoTrunc = 0;
  (void)notUsed1;
  return SQLITE_OK;
}

/*
** Invoke this routine to register the "dbpage" virtual table module
*/
SQLITE_PRIVATE int sqlite3DbpageRegister(sqlite3 *db){
  static sqlite3_module dbpage_module = {
    2,                            /* iVersion */
    dbpageConnect,                /* xCreate */
    dbpageConnect,                /* xConnect */
    dbpageBestIndex,              /* xBestIndex */
    dbpageDisconnect,             /* xDisconnect */
    dbpageDisconnect,             /* xDestroy */
    dbpageOpen,                   /* xOpen - open a cursor */
    dbpageClose,                  /* xClose - close a cursor */
    dbpageFilter,                 /* xFilter - configure scan constraints */
    dbpageNext,                   /* xNext - advance a cursor */
    dbpageEof,                    /* xEof - check for end of scan */
    dbpageColumn,                 /* xColumn - read data */
    dbpageRowid,                  /* xRowid - read data */
    dbpageUpdate,                 /* xUpdate */
    dbpageBegin,                  /* xBegin */
    dbpageSync,                   /* xSync */
    0,                            /* xCommit */
    0,                            /* xRollback */
    0,                            /* xFindMethod */
    0,                            /* xRename */
    0,                            /* xSavepoint */
    0,                            /* xRelease */
    dbpageRollbackTo,             /* xRollbackTo */
    0,                            /* xShadowName */
    0                             /* xIntegrity */
  };
  return sqlite3_create_module(db, "sqlite_dbpage", &dbpage_module, 0);
}
#elif defined(SQLITE_ENABLE_DBPAGE_VTAB)
SQLITE_PRIVATE int sqlite3DbpageRegister(sqlite3 *db){ return SQLITE_OK; }
#endif /* SQLITE_ENABLE_DBSTAT_VTAB */

/************** End of dbpage.c **********************************************/
/************** Begin file carray.c ******************************************/
/*
** 2016-06-29
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file implements a table-valued-function that
** returns the values in a C-language array.
** Examples:
**
**      SELECT * FROM carray($ptr,5)
**
** The query above returns 5 integers contained in a C-language array
** at the address $ptr.  $ptr is a pointer to the array of integers.
** The pointer value must be assigned to $ptr using the
** sqlite3_bind_pointer() interface with a pointer type of "carray".
** For example:
**
**    static int aX[] = { 53, 9, 17, 2231, 4, 99 };
**    int i = sqlite3_bind_parameter_index(pStmt, "$ptr");
**    sqlite3_bind_pointer(pStmt, i, aX, "carray", 0);
**
** There is an optional third parameter to determine the datatype of
** the C-language array.  Allowed values of the third parameter are
** 'int32', 'int64', 'double', 'char*', 'struct iovec'.  Example:
**
**      SELECT * FROM carray($ptr,10,'char*');
**
** The default value of the third parameter is 'int32'.
**
** HOW IT WORKS
**
** The carray "function" is really a virtual table with the
** following schema:
**
**     CREATE TABLE carray(
**       value,
**       pointer HIDDEN,
**       count HIDDEN,
**       ctype TEXT HIDDEN
**     );
**
** If the hidden columns "pointer" and "count" are unconstrained, then
** the virtual table has no rows.  Otherwise, the virtual table interprets
** the integer value of "pointer" as a pointer to the array and "count"
** as the number of elements in the array.  The virtual table steps through
** the array, element by element.
*/
#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_ENABLE_CARRAY)
/* #include "sqliteInt.h" */
#if defined(_WIN32) || defined(__RTP__) || defined(_WRS_KERNEL)
  struct iovec {
    void *iov_base;
    size_t iov_len;
  };
#else
# include <sys/uio.h>
#endif

/*
** Names of allowed datatypes
*/
static const char *azCarrayType[] = {
  "int32", "int64", "double", "char*", "struct iovec"
};

/*
** Structure used to hold the sqlite3_carray_bind() information
*/
typedef struct carray_bind carray_bind;
struct carray_bind {
  void *aData;                /* The data */
  int nData;                  /* Number of elements */
  int mFlags;                 /* Control flags */
  void (*xDel)(void*);        /* Destructor for aData */
};


/* carray_cursor is a subclass of sqlite3_vtab_cursor which will
** serve as the underlying representation of a cursor that scans
** over rows of the result
*/
typedef struct carray_cursor carray_cursor;
struct carray_cursor {
  sqlite3_vtab_cursor base;  /* Base class - must be first */
  sqlite3_int64 iRowid;      /* The rowid */
  void *pPtr;                /* Pointer to the array of values */
  sqlite3_int64 iCnt;        /* Number of integers in the array */
  unsigned char eType;       /* One of the CARRAY_type values */
};

/*
** The carrayConnect() method is invoked to create a new
** carray_vtab that describes the carray virtual table.
**
** Think of this routine as the constructor for carray_vtab objects.
**
** All this routine needs to do is:
**
**    (1) Allocate the carray_vtab object and initialize all fields.
**
**    (2) Tell SQLite (via the sqlite3_declare_vtab() interface) what the
**        result set of queries against carray will look like.
*/
static int carrayConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  sqlite3_vtab *pNew;
  int rc;

/* Column numbers */
#define CARRAY_COLUMN_VALUE   0
#define CARRAY_COLUMN_POINTER 1
#define CARRAY_COLUMN_COUNT   2
#define CARRAY_COLUMN_CTYPE   3

  rc = sqlite3_declare_vtab(db,
     "CREATE TABLE x(value,pointer hidden,count hidden,ctype hidden)");
  if( rc==SQLITE_OK ){
    pNew = *ppVtab = sqlite3_malloc( sizeof(*pNew) );
    if( pNew==0 ) return SQLITE_NOMEM;
    memset(pNew, 0, sizeof(*pNew));
  }
  return rc;
}

/*
** This method is the destructor for carray_cursor objects.
*/
static int carrayDisconnect(sqlite3_vtab *pVtab){
  sqlite3_free(pVtab);
  return SQLITE_OK;
}

/*
** Constructor for a new carray_cursor object.
*/
static int carrayOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
  carray_cursor *pCur;
  pCur = sqlite3_malloc( sizeof(*pCur) );
  if( pCur==0 ) return SQLITE_NOMEM;
  memset(pCur, 0, sizeof(*pCur));
  *ppCursor = &pCur->base;
  return SQLITE_OK;
}

/*
** Destructor for a carray_cursor.
*/
static int carrayClose(sqlite3_vtab_cursor *cur){
  sqlite3_free(cur);
  return SQLITE_OK;
}


/*
** Advance a carray_cursor to its next row of output.
*/
static int carrayNext(sqlite3_vtab_cursor *cur){
  carray_cursor *pCur = (carray_cursor*)cur;
  pCur->iRowid++;
  return SQLITE_OK;
}

/*
** Return values of columns for the row at which the carray_cursor
** is currently pointing.
*/
static int carrayColumn(
  sqlite3_vtab_cursor *cur,   /* The cursor */
  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
  int i                       /* Which column to return */
){
  carray_cursor *pCur = (carray_cursor*)cur;
  sqlite3_int64 x = 0;
  switch( i ){
    case CARRAY_COLUMN_POINTER:   return SQLITE_OK;
    case CARRAY_COLUMN_COUNT:     x = pCur->iCnt;   break;
    case CARRAY_COLUMN_CTYPE: {
      sqlite3_result_text(ctx, azCarrayType[pCur->eType], -1, SQLITE_STATIC);
      return SQLITE_OK;
    }
    default: {
      switch( pCur->eType ){
        case CARRAY_INT32: {
          int *p = (int*)pCur->pPtr;
          sqlite3_result_int(ctx, p[pCur->iRowid-1]);
          return SQLITE_OK;
        }
        case CARRAY_INT64: {
          sqlite3_int64 *p = (sqlite3_int64*)pCur->pPtr;
          sqlite3_result_int64(ctx, p[pCur->iRowid-1]);
          return SQLITE_OK;
        }
        case CARRAY_DOUBLE: {
          double *p = (double*)pCur->pPtr;
          sqlite3_result_double(ctx, p[pCur->iRowid-1]);
          return SQLITE_OK;
        }
        case CARRAY_TEXT: {
          const char **p = (const char**)pCur->pPtr;
          sqlite3_result_text(ctx, p[pCur->iRowid-1], -1, SQLITE_TRANSIENT);
          return SQLITE_OK;
        }
        default: {
          const struct iovec *p = (struct iovec*)pCur->pPtr;
          assert( pCur->eType==CARRAY_BLOB );
          sqlite3_result_blob(ctx, p[pCur->iRowid-1].iov_base,
                              (int)p[pCur->iRowid-1].iov_len, SQLITE_TRANSIENT);
          return SQLITE_OK;
        }
      }
    }
  }
  sqlite3_result_int64(ctx, x);
  return SQLITE_OK;
}

/*
** Return the rowid for the current row.  In this implementation, the
** rowid is the same as the output value.
*/
static int carrayRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  carray_cursor *pCur = (carray_cursor*)cur;
  *pRowid = pCur->iRowid;
  return SQLITE_OK;
}

/*
** Return TRUE if the cursor has been moved off of the last
** row of output.
*/
static int carrayEof(sqlite3_vtab_cursor *cur){
  carray_cursor *pCur = (carray_cursor*)cur;
  return pCur->iRowid>pCur->iCnt;
}

/*
** This method is called to "rewind" the carray_cursor object back
** to the first row of output.
*/
static int carrayFilter(
  sqlite3_vtab_cursor *pVtabCursor,
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  carray_cursor *pCur = (carray_cursor *)pVtabCursor;
  pCur->pPtr = 0;
  pCur->iCnt = 0;
  switch( idxNum ){
    case 1: {
      carray_bind *pBind = sqlite3_value_pointer(argv[0], "carray-bind");
      if( pBind==0 ) break;
      pCur->pPtr = pBind->aData;
      pCur->iCnt = pBind->nData;
      pCur->eType = pBind->mFlags & 0x07;
      break;
    }
    case 2:
    case 3: {
      pCur->pPtr = sqlite3_value_pointer(argv[0], "carray");
      pCur->iCnt = pCur->pPtr ? sqlite3_value_int64(argv[1]) : 0;
      if( idxNum<3 ){
        pCur->eType = CARRAY_INT32;
      }else{
        unsigned char i;
        const char *zType = (const char*)sqlite3_value_text(argv[2]);
        for(i=0; i<sizeof(azCarrayType)/sizeof(azCarrayType[0]); i++){
          if( sqlite3_stricmp(zType, azCarrayType[i])==0 ) break;
        }
        if( i>=sizeof(azCarrayType)/sizeof(azCarrayType[0]) ){
          pVtabCursor->pVtab->zErrMsg = sqlite3_mprintf(
            "unknown datatype: %Q", zType);
          return SQLITE_ERROR;
        }else{
          pCur->eType = i;
        }
      }
      break;
    }
  }
  pCur->iRowid = 1;
  return SQLITE_OK;
}

/*
** SQLite will invoke this method one or more times while planning a query
** that uses the carray virtual table.  This routine needs to create
** a query plan for each invocation and compute an estimated cost for that
** plan.
**
** In this implementation idxNum is used to represent the
** query plan.  idxStr is unused.
**
** idxNum is:
**
**    1    If only the pointer= constraint exists.  In this case, the
**         parameter must be bound using sqlite3_carray_bind().
**
**    2    if the pointer= and count= constraints exist.
**
**    3    if the ctype= constraint also exists.
**
** idxNum is 0 otherwise and carray becomes an empty table.
*/
static int carrayBestIndex(
  sqlite3_vtab *tab,

sqlite3.c  view on Meta::CPAN

  pConstraint = pIdxInfo->aConstraint;
  for(i=0; i<pIdxInfo->nConstraint; i++, pConstraint++){
    if( pConstraint->op!=SQLITE_INDEX_CONSTRAINT_EQ ) continue;
    if( pConstraint->iColumn>=0 ) seen |= 1 << pConstraint->iColumn;
    if( pConstraint->usable==0 ) continue;
    switch( pConstraint->iColumn ){
      case CARRAY_COLUMN_POINTER:
        ptrIdx = i;
        break;
      case CARRAY_COLUMN_COUNT:
        cntIdx = i;
        break;
      case CARRAY_COLUMN_CTYPE:
        ctypeIdx = i;
        break;
    }
  }
  if( ptrIdx>=0 ){
    pIdxInfo->aConstraintUsage[ptrIdx].argvIndex = 1;
    pIdxInfo->aConstraintUsage[ptrIdx].omit = 1;
    pIdxInfo->estimatedCost = (double)1;
    pIdxInfo->estimatedRows = 100;
    pIdxInfo->idxNum = 1;
    if( cntIdx>=0 ){
      pIdxInfo->aConstraintUsage[cntIdx].argvIndex = 2;
      pIdxInfo->aConstraintUsage[cntIdx].omit = 1;
      pIdxInfo->idxNum = 2;
      if( ctypeIdx>=0 ){
        pIdxInfo->aConstraintUsage[ctypeIdx].argvIndex = 3;
        pIdxInfo->aConstraintUsage[ctypeIdx].omit = 1;
        pIdxInfo->idxNum = 3;
      }else if( seen & (1<<CARRAY_COLUMN_CTYPE) ){
        /* In a three-argument carray(), we need to know the value of all
        ** three arguments */
        return SQLITE_CONSTRAINT;
      }
    }else if( seen & (1<<CARRAY_COLUMN_COUNT) ){
      /* In a two-argument carray(), we need to know the value of both
      ** arguments */
      return SQLITE_CONSTRAINT;
    }
  }else{
    pIdxInfo->estimatedCost = (double)2147483647;
    pIdxInfo->estimatedRows = 2147483647;
    pIdxInfo->idxNum = 0;
  }
  return SQLITE_OK;
}

/*
** This following structure defines all the methods for the
** carray virtual table.
*/
static sqlite3_module carrayModule = {
  0,                         /* iVersion */
  0,                         /* xCreate */
  carrayConnect,             /* xConnect */
  carrayBestIndex,           /* xBestIndex */
  carrayDisconnect,          /* xDisconnect */
  0,                         /* xDestroy */
  carrayOpen,                /* xOpen - open a cursor */
  carrayClose,               /* xClose - close a cursor */
  carrayFilter,              /* xFilter - configure scan constraints */
  carrayNext,                /* xNext - advance a cursor */
  carrayEof,                 /* xEof - check for end of scan */
  carrayColumn,              /* xColumn - read data */
  carrayRowid,               /* xRowid - read data */
  0,                         /* xUpdate */
  0,                         /* xBegin */
  0,                         /* xSync */
  0,                         /* xCommit */
  0,                         /* xRollback */
  0,                         /* xFindMethod */
  0,                         /* xRename */
  0,                         /* xSavepoint */
  0,                         /* xRelease */
  0,                         /* xRollbackTo */
  0,                         /* xShadow */
  0                          /* xIntegrity */
};

/*
** Destructor for the carray_bind object
*/
static void carrayBindDel(void *pPtr){
  carray_bind *p = (carray_bind*)pPtr;
  if( p->xDel!=SQLITE_STATIC ){
     p->xDel(p->aData);
  }
  sqlite3_free(p);
}

/*
** Invoke this interface in order to bind to the single-argument
** version of CARRAY().
*/
SQLITE_API int sqlite3_carray_bind(
  sqlite3_stmt *pStmt,
  int idx,
  void *aData,
  int nData,
  int mFlags,
  void (*xDestroy)(void*)
){
  carray_bind *pNew = 0;
  int i;
  int rc = SQLITE_OK;

  /* Ensure that the mFlags value is acceptable. */
  assert( CARRAY_INT32==0 && CARRAY_INT64==1 && CARRAY_DOUBLE==2 );
  assert( CARRAY_TEXT==3 && CARRAY_BLOB==4 );
  if( mFlags<CARRAY_INT32 || mFlags>CARRAY_BLOB ){
    rc = SQLITE_ERROR;
    goto carray_bind_error;
  }

  pNew = sqlite3_malloc64(sizeof(*pNew));
  if( pNew==0 ){
    rc = SQLITE_NOMEM;
    goto carray_bind_error;
  }

  pNew->nData = nData;
  pNew->mFlags = mFlags;

sqlite3.c  view on Meta::CPAN

  return (h % nBucket);
}

/*
** Arguments aLeft and aRight are pointers to change records for table pTab.
** This function returns true if the two records apply to the same row (i.e.
** have the same values stored in the primary key columns), or false
** otherwise.
*/
static int sessionChangeEqual(
  SessionTable *pTab,             /* Table used for PK definition */
  int bLeftPkOnly,                /* True if aLeft[] contains PK fields only */
  u8 *aLeft,                      /* Change record */
  int bRightPkOnly,               /* True if aRight[] contains PK fields only */
  u8 *aRight                      /* Change record */
){
  u8 *a1 = aLeft;                 /* Cursor to iterate through aLeft */
  u8 *a2 = aRight;                /* Cursor to iterate through aRight */
  int iCol;                       /* Used to iterate through table columns */

  for(iCol=0; iCol<pTab->nCol; iCol++){
    if( pTab->abPK[iCol] ){
      int n1 = sessionSerialLen(a1);
      int n2 = sessionSerialLen(a2);

      if( n1!=n2 || memcmp(a1, a2, n1) ){
        return 0;
      }
      a1 += n1;
      a2 += n2;
    }else{
      if( bLeftPkOnly==0 ) a1 += sessionSerialLen(a1);
      if( bRightPkOnly==0 ) a2 += sessionSerialLen(a2);
    }
  }

  return 1;
}

/*
** Arguments aLeft and aRight both point to buffers containing change
** records with nCol columns. This function "merges" the two records into
** a single records which is written to the buffer at *paOut. *paOut is
** then set to point to one byte after the last byte written before
** returning.
**
** The merging of records is done as follows: For each column, if the
** aRight record contains a value for the column, copy the value from
** their. Otherwise, if aLeft contains a value, copy it. If neither
** record contains a value for a given column, then neither does the
** output record.
*/
static void sessionMergeRecord(
  u8 **paOut,
  int nCol,
  u8 *aLeft,
  u8 *aRight
){
  u8 *a1 = aLeft;                 /* Cursor used to iterate through aLeft */
  u8 *a2 = aRight;                /* Cursor used to iterate through aRight */
  u8 *aOut = *paOut;              /* Output cursor */
  int iCol;                       /* Used to iterate from 0 to nCol */

  for(iCol=0; iCol<nCol; iCol++){
    int n1 = sessionSerialLen(a1);
    int n2 = sessionSerialLen(a2);
    if( *a2 ){
      memcpy(aOut, a2, n2);
      aOut += n2;
    }else{
      memcpy(aOut, a1, n1);
      aOut += n1;
    }
    a1 += n1;
    a2 += n2;
  }

  *paOut = aOut;
}

/*
** This is a helper function used by sessionMergeUpdate().
**
** When this function is called, both *paOne and *paTwo point to a value
** within a change record. Before it returns, both have been advanced so
** as to point to the next value in the record.
**
** If, when this function is called, *paTwo points to a valid value (i.e.
** *paTwo[0] is not 0x00 - the "no value" placeholder), a copy of the *paTwo
** pointer is returned and *pnVal is set to the number of bytes in the
** serialized value. Otherwise, a copy of *paOne is returned and *pnVal
** set to the number of bytes in the value at *paOne. If *paOne points
** to the "no value" placeholder, *pnVal is set to 1. In other words:
**
**   if( *paTwo is valid ) return *paTwo;
**   return *paOne;
**
*/
static u8 *sessionMergeValue(
  u8 **paOne,                     /* IN/OUT: Left-hand buffer pointer */
  u8 **paTwo,                     /* IN/OUT: Right-hand buffer pointer */
  int *pnVal                      /* OUT: Bytes in returned value */
){
  u8 *a1 = *paOne;
  u8 *a2 = *paTwo;
  u8 *pRet = 0;
  int n1;

  assert( a1 );
  if( a2 ){
    int n2 = sessionSerialLen(a2);
    if( *a2 ){
      *pnVal = n2;
      pRet = a2;
    }
    *paTwo = &a2[n2];
  }

  n1 = sessionSerialLen(a1);
  if( pRet==0 ){
    *pnVal = n1;

sqlite3.c  view on Meta::CPAN

        if( *p=='\'' ){
          p++;
          if( *p!='\'' ) break;
        }
        p++;
        if( *p==0 ) p = 0;
      }
      break;

    default:
      /* maybe a number */
      if( *p=='+' || *p=='-' ) p++;
      while( fts5_isdigit(*p) ) p++;

      /* At this point, if the literal was an integer, the parse is
      ** finished. Or, if it is a floating point value, it may continue
      ** with either a decimal point or an 'E' character. */
      if( *p=='.' && fts5_isdigit(p[1]) ){
        p += 2;
        while( fts5_isdigit(*p) ) p++;
      }
      if( p==pIn ) p = 0;

      break;
  }

  return p;
}

/*
** The first character of the string pointed to by argument z is guaranteed
** to be an open-quote character (see function fts5_isopenquote()).
**
** This function searches for the corresponding close-quote character within
** the string and, if found, dequotes the string in place and adds a new
** nul-terminator byte.
**
** If the close-quote is found, the value returned is the byte offset of
** the character immediately following it. Or, if the close-quote is not
** found, -1 is returned. If -1 is returned, the buffer is left in an
** undefined state.
*/
static int fts5Dequote(char *z){
  char q;
  int iIn = 1;
  int iOut = 0;
  q = z[0];

  /* Set stack variable q to the close-quote character */
  assert( q=='[' || q=='\'' || q=='"' || q=='`' );
  if( q=='[' ) q = ']';

  while( z[iIn] ){
    if( z[iIn]==q ){
      if( z[iIn+1]!=q ){
        /* Character iIn was the close quote. */
        iIn++;
        break;
      }else{
        /* Character iIn and iIn+1 form an escaped quote character. Skip
        ** the input cursor past both and copy a single quote character
        ** to the output buffer. */
        iIn += 2;
        z[iOut++] = q;
      }
    }else{
      z[iOut++] = z[iIn++];
    }
  }

  z[iOut] = '\0';
  return iIn;
}

/*
** Convert an SQL-style quoted string into a normal string by removing
** the quote characters.  The conversion is done in-place.  If the
** input does not begin with a quote character, then this routine
** is a no-op.
**
** Examples:
**
**     "abc"   becomes   abc
**     'xyz'   becomes   xyz
**     [pqr]   becomes   pqr
**     `mno`   becomes   mno
*/
static void sqlite3Fts5Dequote(char *z){
  char quote;                     /* Quote character (if any ) */

  assert( 0==fts5_iswhitespace(z[0]) );
  quote = z[0];
  if( quote=='[' || quote=='\'' || quote=='"' || quote=='`' ){
    fts5Dequote(z);
  }
}


struct Fts5Enum {
  const char *zName;
  int eVal;
};
typedef struct Fts5Enum Fts5Enum;

static int fts5ConfigSetEnum(
  const Fts5Enum *aEnum,
  const char *zEnum,
  int *peVal
){
  int nEnum = (int)strlen(zEnum);
  int i;
  int iVal = -1;

  for(i=0; aEnum[i].zName; i++){
    if( sqlite3_strnicmp(aEnum[i].zName, zEnum, nEnum)==0 ){
      if( iVal>=0 ) return SQLITE_ERROR;
      iVal = aEnum[i].eVal;
    }
  }

  *peVal = iVal;

sqlite3.c  view on Meta::CPAN

  int nEmpty;                     /* Number of contiguous term-less nodes */

  int nDlidx;                     /* Allocated size of aDlidx[] array */
  Fts5DlidxWriter *aDlidx;        /* Array of Fts5DlidxWriter objects */

  /* Values to insert into the %_idx table */
  Fts5Buffer btterm;              /* Next term to insert into %_idx table */
  int iBtPage;                    /* Page number corresponding to btterm */
};

typedef struct Fts5CResult Fts5CResult;
struct Fts5CResult {
  u16 iFirst;                     /* aSeg[] index of firstest iterator */
  u8 bTermEq;                     /* True if the terms are equal */
};

/*
** Object for iterating through a single segment, visiting each term/rowid
** pair in the segment.
**
** pSeg:
**   The segment to iterate through.
**
** iLeafPgno:
**   Current leaf page number within segment.
**
** iLeafOffset:
**   Byte offset within the current leaf that is the first byte of the
**   position list data (one byte passed the position-list size field).
**
** pLeaf:
**   Buffer containing current leaf page data. Set to NULL at EOF.
**
** iTermLeafPgno, iTermLeafOffset:
**   Leaf page number containing the last term read from the segment. And
**   the offset immediately following the term data.
**
** flags:
**   Mask of FTS5_SEGITER_XXX values. Interpreted as follows:
**
**   FTS5_SEGITER_ONETERM:
**     If set, set the iterator to point to EOF after the current doclist
**     has been exhausted. Do not proceed to the next term in the segment.
**
**   FTS5_SEGITER_REVERSE:
**     This flag is only ever set if FTS5_SEGITER_ONETERM is also set. If
**     it is set, iterate through rowid in descending order instead of the
**     default ascending order.
**
** iRowidOffset/nRowidOffset/aRowidOffset:
**     These are used if the FTS5_SEGITER_REVERSE flag is set.
**
**     For each rowid on the page corresponding to the current term, the
**     corresponding aRowidOffset[] entry is set to the byte offset of the
**     start of the "position-list-size" field within the page.
**
** iTermIdx:
**     Index of current term on iTermLeafPgno.
**
** apTombstone/nTombstone:
**     These are used for contentless_delete=1 tables only. When the cursor
**     is first allocated, the apTombstone[] array is allocated so that it
**     is large enough for all tombstones hash pages associated with the
**     segment. The pages themselves are loaded lazily from the database as
**     they are required.
*/
struct Fts5SegIter {
  Fts5StructureSegment *pSeg;     /* Segment to iterate through */
  int flags;                      /* Mask of configuration flags */
  int iLeafPgno;                  /* Current leaf page number */
  Fts5Data *pLeaf;                /* Current leaf data */
  Fts5Data *pNextLeaf;            /* Leaf page (iLeafPgno+1) */
  i64 iLeafOffset;                /* Byte offset within current leaf */
  Fts5TombstoneArray *pTombArray; /* Array of tombstone pages */

  /* Next method */
  void (*xNext)(Fts5Index*, Fts5SegIter*, int*);

  /* The page and offset from which the current term was read. The offset
  ** is the offset of the first rowid in the current doclist.  */
  int iTermLeafPgno;
  int iTermLeafOffset;

  int iPgidxOff;                  /* Next offset in pgidx */
  int iEndofDoclist;

  /* The following are only used if the FTS5_SEGITER_REVERSE flag is set. */
  int iRowidOffset;               /* Current entry in aRowidOffset[] */
  int nRowidOffset;               /* Allocated size of aRowidOffset[] array */
  int *aRowidOffset;              /* Array of offset to rowid fields */

  Fts5DlidxIter *pDlidx;          /* If there is a doclist-index */

  /* Variables populated based on current entry. */
  Fts5Buffer term;                /* Current term */
  i64 iRowid;                     /* Current rowid */
  int nPos;                       /* Number of bytes in current position list */
  u8 bDel;                        /* True if the delete flag is set */
};

static int fts5IndexCorruptRowid(Fts5Index *pIdx, i64 iRowid){
  pIdx->rc = FTS5_CORRUPT;
  sqlite3Fts5ConfigErrmsg(pIdx->pConfig,
      "fts5: corruption found reading blob %lld from table \"%s\"",
      iRowid, pIdx->pConfig->zName
  );
  return SQLITE_CORRUPT_VTAB;
}
#define FTS5_CORRUPT_ROWID(pIdx, iRowid) fts5IndexCorruptRowid(pIdx, iRowid)

static int fts5IndexCorruptIter(Fts5Index *pIdx, Fts5SegIter *pIter){
  pIdx->rc = FTS5_CORRUPT;
  sqlite3Fts5ConfigErrmsg(pIdx->pConfig,
      "fts5: corruption on page %d, segment %d, table \"%s\"",
      pIter->iLeafPgno, pIter->pSeg->iSegid, pIdx->pConfig->zName
  );
  return SQLITE_CORRUPT_VTAB;
}
#define FTS5_CORRUPT_ITER(pIdx, pIter) fts5IndexCorruptIter(pIdx, pIter)

static int fts5IndexCorruptIdx(Fts5Index *pIdx){

sqlite3.c  view on Meta::CPAN


    fts5BufferFree(&term);
  }

 decode_out:
  sqlite3_free(a);
  if( rc==SQLITE_OK ){
    sqlite3_result_text(pCtx, (const char*)s.p, s.n, SQLITE_TRANSIENT);
  }else{
    sqlite3_result_error_code(pCtx, rc);
  }
  fts5BufferFree(&s);
}
#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */

#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
/*
** The implementation of user-defined scalar function fts5_rowid().
*/
static void fts5RowidFunction(
  sqlite3_context *pCtx,          /* Function call context */
  int nArg,                       /* Number of args (always 2) */
  sqlite3_value **apVal           /* Function arguments */
){
  const char *zArg;
  if( nArg==0 ){
    sqlite3_result_error(pCtx, "should be: fts5_rowid(subject, ....)", -1);
  }else{
    zArg = (const char*)sqlite3_value_text(apVal[0]);
    if( 0==sqlite3_stricmp(zArg, "segment") ){
      i64 iRowid;
      int segid, pgno;
      if( nArg!=3 ){
        sqlite3_result_error(pCtx,
            "should be: fts5_rowid('segment', segid, pgno))", -1
        );
      }else{
        segid = sqlite3_value_int(apVal[1]);
        pgno = sqlite3_value_int(apVal[2]);
        iRowid = FTS5_SEGMENT_ROWID(segid, pgno);
        sqlite3_result_int64(pCtx, iRowid);
      }
    }else{
      sqlite3_result_error(pCtx,
        "first arg to fts5_rowid() must be 'segment'" , -1
      );
    }
  }
}
#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */

#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)

typedef struct Fts5StructVtab Fts5StructVtab;
struct Fts5StructVtab {
  sqlite3_vtab base;
};

typedef struct Fts5StructVcsr Fts5StructVcsr;
struct Fts5StructVcsr {
  sqlite3_vtab_cursor base;
  Fts5Structure *pStruct;
  int iLevel;
  int iSeg;
  int iRowid;
};

/*
** Create a new fts5_structure() table-valued function.
*/
static int fts5structConnectMethod(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  Fts5StructVtab *pNew = 0;
  int rc = SQLITE_OK;

  rc = sqlite3_declare_vtab(db,
      "CREATE TABLE xyz("
          "level, segment, merge, segid, leaf1, leaf2, loc1, loc2, "
          "npgtombstone, nentrytombstone, nentry, struct HIDDEN);"
  );
  if( rc==SQLITE_OK ){
    pNew = sqlite3Fts5MallocZero(&rc, sizeof(*pNew));
  }

  *ppVtab = (sqlite3_vtab*)pNew;
  return rc;
}

/*
** We must have a single struct=? constraint that will be passed through
** into the xFilter method.  If there is no valid struct=? constraint,
** then return an SQLITE_CONSTRAINT error.
*/
static int fts5structBestIndexMethod(
  sqlite3_vtab *tab,
  sqlite3_index_info *pIdxInfo
){
  int i;
  int rc = SQLITE_CONSTRAINT;
  struct sqlite3_index_constraint *p;
  pIdxInfo->estimatedCost = (double)100;
  pIdxInfo->estimatedRows = 100;
  pIdxInfo->idxNum = 0;
  for(i=0, p=pIdxInfo->aConstraint; i<pIdxInfo->nConstraint; i++, p++){
    if( p->usable==0 ) continue;
    if( p->op==SQLITE_INDEX_CONSTRAINT_EQ && p->iColumn==11 ){
      rc = SQLITE_OK;
      pIdxInfo->aConstraintUsage[i].omit = 1;
      pIdxInfo->aConstraintUsage[i].argvIndex = 1;
      break;
    }
  }
  return rc;
}

/*
** This method is the destructor for bytecodevtab objects.
*/
static int fts5structDisconnectMethod(sqlite3_vtab *pVtab){
  Fts5StructVtab *p = (Fts5StructVtab*)pVtab;
  sqlite3_free(p);
  return SQLITE_OK;
}

/*
** Constructor for a new bytecodevtab_cursor object.
*/
static int fts5structOpenMethod(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCsr){
  int rc = SQLITE_OK;
  Fts5StructVcsr *pNew = 0;

  pNew = sqlite3Fts5MallocZero(&rc, sizeof(*pNew));
  *ppCsr = (sqlite3_vtab_cursor*)pNew;

  return SQLITE_OK;
}

/*
** Destructor for a bytecodevtab_cursor.
*/
static int fts5structCloseMethod(sqlite3_vtab_cursor *cur){
  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
  fts5StructureRelease(pCsr->pStruct);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}


/*
** Advance a bytecodevtab_cursor to its next row of output.
*/
static int fts5structNextMethod(sqlite3_vtab_cursor *cur){
  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
  Fts5Structure *p = pCsr->pStruct;

  assert( pCsr->pStruct );
  pCsr->iSeg++;
  pCsr->iRowid++;
  while( pCsr->iLevel<p->nLevel && pCsr->iSeg>=p->aLevel[pCsr->iLevel].nSeg ){
    pCsr->iLevel++;
    pCsr->iSeg = 0;
  }
  if( pCsr->iLevel>=p->nLevel ){
    fts5StructureRelease(pCsr->pStruct);
    pCsr->pStruct = 0;
  }
  return SQLITE_OK;
}

/*
** Return TRUE if the cursor has been moved off of the last
** row of output.
*/
static int fts5structEofMethod(sqlite3_vtab_cursor *cur){
  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
  return pCsr->pStruct==0;
}

static int fts5structRowidMethod(
  sqlite3_vtab_cursor *cur,
  sqlite_int64 *piRowid
){
  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
  *piRowid = pCsr->iRowid;
  return SQLITE_OK;
}

/*
** Return values of columns for the row at which the bytecodevtab_cursor
** is currently pointing.
*/
static int fts5structColumnMethod(
  sqlite3_vtab_cursor *cur,   /* The cursor */
  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
  int i                       /* Which column to return */
){
  Fts5StructVcsr *pCsr = (Fts5StructVcsr*)cur;
  Fts5Structure *p = pCsr->pStruct;
  Fts5StructureSegment *pSeg = &p->aLevel[pCsr->iLevel].aSeg[pCsr->iSeg];

  switch( i ){
    case 0: /* level */
      sqlite3_result_int(ctx, pCsr->iLevel);
      break;
    case 1: /* segment */
      sqlite3_result_int(ctx, pCsr->iSeg);
      break;
    case 2: /* merge */
      sqlite3_result_int(ctx, pCsr->iSeg < p->aLevel[pCsr->iLevel].nMerge);
      break;
    case 3: /* segid */
      sqlite3_result_int(ctx, pSeg->iSegid);
      break;
    case 4: /* leaf1 */
      sqlite3_result_int(ctx, pSeg->pgnoFirst);
      break;
    case 5: /* leaf2 */
      sqlite3_result_int(ctx, pSeg->pgnoLast);
      break;
    case 6: /* origin1 */
      sqlite3_result_int64(ctx, pSeg->iOrigin1);
      break;
    case 7: /* origin2 */
      sqlite3_result_int64(ctx, pSeg->iOrigin2);
      break;
    case 8: /* npgtombstone */
      sqlite3_result_int(ctx, pSeg->nPgTombstone);
      break;
    case 9: /* nentrytombstone */
      sqlite3_result_int64(ctx, pSeg->nEntryTombstone);
      break;
    case 10: /* nentry */
      sqlite3_result_int64(ctx, pSeg->nEntry);
      break;
  }
  return SQLITE_OK;
}

/*
** Initialize a cursor.
**
**    idxNum==0     means show all subprograms
**    idxNum==1     means show only the main bytecode and omit subprograms.
*/
static int fts5structFilterMethod(
  sqlite3_vtab_cursor *pVtabCursor,
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  Fts5StructVcsr *pCsr = (Fts5StructVcsr *)pVtabCursor;
  int rc = SQLITE_OK;

  const u8 *aBlob = 0;
  int nBlob = 0;

  assert( argc==1 );
  fts5StructureRelease(pCsr->pStruct);
  pCsr->pStruct = 0;

  nBlob = sqlite3_value_bytes(argv[0]);
  aBlob = (const u8*)sqlite3_value_blob(argv[0]);
  rc = fts5StructureDecode(aBlob, nBlob, 0, &pCsr->pStruct);
  if( rc==SQLITE_OK ){
    pCsr->iLevel = 0;
    pCsr->iRowid = 0;
    pCsr->iSeg = -1;
    rc = fts5structNextMethod(pVtabCursor);
  }

  return rc;
}

#endif /* SQLITE_TEST || SQLITE_FTS5_DEBUG */

/*
** This is called as part of registering the FTS5 module with database
** connection db. It registers several user-defined scalar functions useful
** with FTS5.
**
** If successful, SQLITE_OK is returned. If an error occurs, some other
** SQLite error code is returned instead.
*/
static int sqlite3Fts5IndexInit(sqlite3 *db){
#if defined(SQLITE_TEST) || defined(SQLITE_FTS5_DEBUG)
  int rc = sqlite3_create_function(
      db, "fts5_decode", 2, SQLITE_UTF8, 0, fts5DecodeFunction, 0, 0
  );

  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(
        db, "fts5_decode_none", 2,
        SQLITE_UTF8, (void*)db, fts5DecodeFunction, 0, 0
    );
  }

  if( rc==SQLITE_OK ){
    rc = sqlite3_create_function(
        db, "fts5_rowid", -1, SQLITE_UTF8, 0, fts5RowidFunction, 0, 0
    );
  }

  if( rc==SQLITE_OK ){
    static const sqlite3_module fts5structure_module = {
      0,                           /* iVersion      */
      0,                           /* xCreate       */
      fts5structConnectMethod,     /* xConnect      */

sqlite3.c  view on Meta::CPAN

** structures should not be corrupt. Otherwise, true. If it is false, extra
** assert() conditions in the fts5 code are activated - conditions that are
** only true if it is guaranteed that the fts5 database is not corrupt.
*/
#ifdef SQLITE_DEBUG
SQLITE_API int sqlite3_fts5_may_be_corrupt = 1;
#endif


typedef struct Fts5Auxdata Fts5Auxdata;
typedef struct Fts5Auxiliary Fts5Auxiliary;
typedef struct Fts5Cursor Fts5Cursor;
typedef struct Fts5FullTable Fts5FullTable;
typedef struct Fts5Sorter Fts5Sorter;
typedef struct Fts5TokenizerModule Fts5TokenizerModule;

/*
** NOTES ON TRANSACTIONS:
**
** SQLite invokes the following virtual table methods as transactions are
** opened and closed by the user:
**
**     xBegin():    Start of a new transaction.
**     xSync():     Initial part of two-phase commit.
**     xCommit():   Final part of two-phase commit.
**     xRollback(): Rollback the transaction.
**
** Anything that is required as part of a commit that may fail is performed
** in the xSync() callback. Current versions of SQLite ignore any errors
** returned by xCommit().
**
** And as sub-transactions are opened/closed:
**
**     xSavepoint(int S):  Open savepoint S.
**     xRelease(int S):    Commit and close savepoint S.
**     xRollbackTo(int S): Rollback to start of savepoint S.
**
** During a write-transaction the fts5_index.c module may cache some data
** in-memory. It is flushed to disk whenever xSync(), xRelease() or
** xSavepoint() is called. And discarded whenever xRollback() or xRollbackTo()
** is called.
**
** Additionally, if SQLITE_DEBUG is defined, an instance of the following
** structure is used to record the current transaction state. This information
** is not required, but it is used in the assert() statements executed by
** function fts5CheckTransactionState() (see below).
*/
struct Fts5TransactionState {
  int eState;                     /* 0==closed, 1==open, 2==synced */
  int iSavepoint;                 /* Number of open savepoints (0 -> none) */
};

/*
** A single object of this type is allocated when the FTS5 module is
** registered with a database handle. It is used to store pointers to
** all registered FTS5 extensions - tokenizers and auxiliary functions.
*/
struct Fts5Global {
  fts5_api api;                   /* User visible part of object (see fts5.h) */
  sqlite3 *db;                    /* Associated database connection */
  i64 iNextId;                    /* Used to allocate unique cursor ids */
  Fts5Auxiliary *pAux;            /* First in list of all aux. functions */
  Fts5TokenizerModule *pTok;      /* First in list of all tokenizer modules */
  Fts5TokenizerModule *pDfltTok;  /* Default tokenizer module */
  Fts5Cursor *pCsr;               /* First in list of all open cursors */
  u32 aLocaleHdr[4];
};

/*
** Size of header on fts5_locale() values. And macro to access a buffer
** containing a copy of the header from an Fts5Config pointer.
*/
#define FTS5_LOCALE_HDR_SIZE ((int)sizeof( ((Fts5Global*)0)->aLocaleHdr ))
#define FTS5_LOCALE_HDR(pConfig) ((const u8*)(pConfig->pGlobal->aLocaleHdr))

#define FTS5_INSTTOKEN_SUBTYPE 73

/*
** Each auxiliary function registered with the FTS5 module is represented
** by an object of the following type. All such objects are stored as part
** of the Fts5Global.pAux list.
*/
struct Fts5Auxiliary {
  Fts5Global *pGlobal;            /* Global context for this function */
  char *zFunc;                    /* Function name (nul-terminated) */
  void *pUserData;                /* User-data pointer */
  fts5_extension_function xFunc;  /* Callback function */
  void (*xDestroy)(void*);        /* Destructor function */
  Fts5Auxiliary *pNext;           /* Next registered auxiliary function */
};

/*
** Each tokenizer module registered with the FTS5 module is represented
** by an object of the following type. All such objects are stored as part
** of the Fts5Global.pTok list.
**
** bV2Native:
**  True if the tokenizer was registered using xCreateTokenizer_v2(), false
**  for xCreateTokenizer(). If this variable is true, then x2 is populated
**  with the routines as supplied by the caller and x1 contains synthesized
**  wrapper routines. In this case the user-data pointer passed to
**  x1.xCreate should be a pointer to the Fts5TokenizerModule structure,
**  not a copy of pUserData.
**
**  Of course, if bV2Native is false, then x1 contains the real routines and
**  x2 the synthesized ones. In this case a pointer to the Fts5TokenizerModule
**  object should be passed to x2.xCreate.
**
**  The synthesized wrapper routines are necessary for xFindTokenizer(_v2)
**  calls.
*/
struct Fts5TokenizerModule {
  char *zName;                    /* Name of tokenizer */
  void *pUserData;                /* User pointer passed to xCreate() */
  int bV2Native;                  /* True if v2 native tokenizer */
  fts5_tokenizer x1;              /* Tokenizer functions */
  fts5_tokenizer_v2 x2;           /* V2 tokenizer functions */
  void (*xDestroy)(void*);        /* Destructor function */
  Fts5TokenizerModule *pNext;     /* Next registered tokenizer module */
};

struct Fts5FullTable {
  Fts5Table p;                    /* Public class members from fts5Int.h */
  Fts5Storage *pStorage;          /* Document store */
  Fts5Global *pGlobal;            /* Global (connection wide) data */
  Fts5Cursor *pSortCsr;           /* Sort data from this cursor */
  int iSavepoint;                 /* Successful xSavepoint()+1 */

#ifdef SQLITE_DEBUG
  struct Fts5TransactionState ts;
#endif
};

struct Fts5MatchPhrase {
  Fts5Buffer *pPoslist;           /* Pointer to current poslist */
  int nTerm;                      /* Size of phrase in terms */
};

/*
** pStmt:
**   SELECT rowid, <fts> FROM <fts> ORDER BY +rank;
**
** aIdx[]:
**   There is one entry in the aIdx[] array for each phrase in the query,
**   the value of which is the offset within aPoslist[] following the last
**   byte of the position list for the corresponding phrase.
*/
struct Fts5Sorter {
  sqlite3_stmt *pStmt;
  i64 iRowid;                     /* Current rowid */
  const u8 *aPoslist;             /* Position lists for current row */
  int nIdx;                       /* Number of entries in aIdx[] */
  int aIdx[FLEXARRAY];            /* Offsets into aPoslist for current row */
};

/* Size (int bytes) of an Fts5Sorter object with N indexes */
#define SZ_FTS5SORTER(N) (offsetof(Fts5Sorter,nIdx)+((N+2)/2)*sizeof(i64))

/*
** Virtual-table cursor object.
**
** iSpecial:
**   If this is a 'special' query (refer to function fts5SpecialMatch()),
**   then this variable contains the result of the query.
**
** iFirstRowid, iLastRowid:
**   These variables are only used for FTS5_PLAN_MATCH cursors. Assuming the
**   cursor iterates in ascending order of rowids, iFirstRowid is the lower
**   limit of rowids to return, and iLastRowid the upper. In other words, the
**   WHERE clause in the user's query might have been:
**
**       <tbl> MATCH <expr> AND rowid BETWEEN $iFirstRowid AND $iLastRowid
**
**   If the cursor iterates in descending order of rowid, iFirstRowid
**   is the upper limit (i.e. the "first" rowid visited) and iLastRowid
**   the lower.
*/
struct Fts5Cursor {
  sqlite3_vtab_cursor base;       /* Base class used by SQLite core */
  Fts5Cursor *pNext;              /* Next cursor in Fts5Cursor.pCsr list */
  int *aColumnSize;               /* Values for xColumnSize() */
  i64 iCsrId;                     /* Cursor id */

  /* Zero from this point onwards on cursor reset */
  int ePlan;                      /* FTS5_PLAN_XXX value */
  int bDesc;                      /* True for "ORDER BY rowid DESC" queries */
  i64 iFirstRowid;                /* Return no rowids earlier than this */
  i64 iLastRowid;                 /* Return no rowids later than this */
  sqlite3_stmt *pStmt;            /* Statement used to read %_content */
  Fts5Expr *pExpr;                /* Expression for MATCH queries */
  Fts5Sorter *pSorter;            /* Sorter for "ORDER BY rank" queries */
  int csrflags;                   /* Mask of cursor flags (see below) */
  i64 iSpecial;                   /* Result of special query */

  /* "rank" function. Populated on demand from vtab.xColumn(). */
  char *zRank;                    /* Custom rank function */
  char *zRankArgs;                /* Custom rank function args */
  Fts5Auxiliary *pRank;           /* Rank callback (or NULL) */
  int nRankArg;                   /* Number of trailing arguments for rank() */
  sqlite3_value **apRankArg;      /* Array of trailing arguments */
  sqlite3_stmt *pRankArgStmt;     /* Origin of objects in apRankArg[] */

  /* Auxiliary data storage */
  Fts5Auxiliary *pAux;            /* Currently executing extension function */
  Fts5Auxdata *pAuxdata;          /* First in linked list of saved aux-data */

  /* Cache used by auxiliary API functions xInst() and xInstCount() */
  Fts5PoslistReader *aInstIter;   /* One for each phrase */
  int nInstAlloc;                 /* Size of aInst[] array (entries / 3) */
  int nInstCount;                 /* Number of phrase instances */
  int *aInst;                     /* 3 integers per phrase instance */
};

/*
** Bits that make up the "idxNum" parameter passed indirectly by
** xBestIndex() to xFilter().
*/
#define FTS5_BI_MATCH        0x0001         /* <tbl> MATCH ? */
#define FTS5_BI_RANK         0x0002         /* rank MATCH ? */
#define FTS5_BI_ROWID_EQ     0x0004         /* rowid == ? */
#define FTS5_BI_ROWID_LE     0x0008         /* rowid <= ? */
#define FTS5_BI_ROWID_GE     0x0010         /* rowid >= ? */

#define FTS5_BI_ORDER_RANK   0x0020
#define FTS5_BI_ORDER_ROWID  0x0040
#define FTS5_BI_ORDER_DESC   0x0080

/*
** Values for Fts5Cursor.csrflags
*/
#define FTS5CSR_EOF               0x01
#define FTS5CSR_REQUIRE_CONTENT   0x02
#define FTS5CSR_REQUIRE_DOCSIZE   0x04
#define FTS5CSR_REQUIRE_INST      0x08
#define FTS5CSR_FREE_ZRANK        0x10
#define FTS5CSR_REQUIRE_RESEEK    0x20
#define FTS5CSR_REQUIRE_POSLIST   0x40

#define BitFlagAllTest(x,y) (((x) & (y))==(y))
#define BitFlagTest(x,y)    (((x) & (y))!=0)


/*
** Macros to Set(), Clear() and Test() cursor flags.
*/
#define CsrFlagSet(pCsr, flag)   ((pCsr)->csrflags |= (flag))
#define CsrFlagClear(pCsr, flag) ((pCsr)->csrflags &= ~(flag))
#define CsrFlagTest(pCsr, flag)  ((pCsr)->csrflags & (flag))

struct Fts5Auxdata {
  Fts5Auxiliary *pAux;            /* Extension to which this belongs */
  void *pPtr;                     /* Pointer value */
  void(*xDelete)(void*);          /* Destructor */
  Fts5Auxdata *pNext;             /* Next object in linked list */
};

#ifdef SQLITE_DEBUG
#define FTS5_BEGIN      1
#define FTS5_SYNC       2
#define FTS5_COMMIT     3
#define FTS5_ROLLBACK   4
#define FTS5_SAVEPOINT  5
#define FTS5_RELEASE    6
#define FTS5_ROLLBACKTO 7
static void fts5CheckTransactionState(Fts5FullTable *p, int op, int iSavepoint){
  switch( op ){
    case FTS5_BEGIN:
      assert( p->ts.eState==0 );
      p->ts.eState = 1;
      p->ts.iSavepoint = -1;
      break;

    case FTS5_SYNC:
      assert( p->ts.eState==1 || p->ts.eState==2 );
      p->ts.eState = 2;
      break;

    case FTS5_COMMIT:
      assert( p->ts.eState==2 );
      p->ts.eState = 0;
      break;

    case FTS5_ROLLBACK:
      assert( p->ts.eState==1 || p->ts.eState==2 || p->ts.eState==0 );
      p->ts.eState = 0;
      break;

    case FTS5_SAVEPOINT:
      assert( p->ts.eState>=1 );
      assert( iSavepoint>=0 );
      assert( iSavepoint>=p->ts.iSavepoint );
      p->ts.iSavepoint = iSavepoint;
      break;

    case FTS5_RELEASE:
      assert( p->ts.eState>=1 );
      assert( iSavepoint>=0 );
      assert( iSavepoint<=p->ts.iSavepoint );
      p->ts.iSavepoint = iSavepoint-1;
      break;

    case FTS5_ROLLBACKTO:
      assert( p->ts.eState>=1 );
      assert( iSavepoint>=-1 );

sqlite3.c  view on Meta::CPAN

    );
  }

  /* Call sqlite3_declare_vtab() */
  if( rc==SQLITE_OK ){
    rc = sqlite3Fts5ConfigDeclareVtab(pConfig);
  }

  /* Load the initial configuration */
  if( rc==SQLITE_OK ){
    rc = sqlite3Fts5ConfigLoad(pTab->p.pConfig, pTab->p.pConfig->iCookie-1);
  }

  if( rc==SQLITE_OK && pConfig->eContent==FTS5_CONTENT_NORMAL ){
    rc = sqlite3_vtab_config(db, SQLITE_VTAB_CONSTRAINT_SUPPORT, (int)1);
  }
  if( rc==SQLITE_OK ){
    rc = sqlite3_vtab_config(db, SQLITE_VTAB_INNOCUOUS);
  }

  if( pConfig ) pConfig->pzErrmsg = 0;
  if( rc!=SQLITE_OK ){
    fts5FreeVtab(pTab);
    pTab = 0;
  }else if( bCreate ){
    fts5CheckTransactionState(pTab, FTS5_BEGIN, 0);
  }
  *ppVTab = (sqlite3_vtab*)pTab;
  return rc;
}

/*
** The xConnect() and xCreate() methods for the virtual table. All the
** work is done in function fts5InitVtab().
*/
static int fts5ConnectMethod(
  sqlite3 *db,                    /* Database connection */
  void *pAux,                     /* Pointer to tokenizer hash table */
  int argc,                       /* Number of elements in argv array */
  const char * const *argv,       /* xCreate/xConnect argument array */
  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
){
  return fts5InitVtab(0, db, pAux, argc, argv, ppVtab, pzErr);
}
static int fts5CreateMethod(
  sqlite3 *db,                    /* Database connection */
  void *pAux,                     /* Pointer to tokenizer hash table */
  int argc,                       /* Number of elements in argv array */
  const char * const *argv,       /* xCreate/xConnect argument array */
  sqlite3_vtab **ppVtab,          /* OUT: New sqlite3_vtab object */
  char **pzErr                    /* OUT: sqlite3_malloc'd error message */
){
  return fts5InitVtab(1, db, pAux, argc, argv, ppVtab, pzErr);
}

/*
** The different query plans.
*/
#define FTS5_PLAN_MATCH          1       /* (<tbl> MATCH ?) */
#define FTS5_PLAN_SOURCE         2       /* A source cursor for SORTED_MATCH */
#define FTS5_PLAN_SPECIAL        3       /* An internal query */
#define FTS5_PLAN_SORTED_MATCH   4       /* (<tbl> MATCH ? ORDER BY rank) */
#define FTS5_PLAN_SCAN           5       /* No usable constraint */
#define FTS5_PLAN_ROWID          6       /* (rowid = ?) */

/*
** Set the SQLITE_INDEX_SCAN_UNIQUE flag in pIdxInfo->flags. Unless this
** extension is currently being used by a version of SQLite too old to
** support index-info flags. In that case this function is a no-op.
*/
static void fts5SetUniqueFlag(sqlite3_index_info *pIdxInfo){
#if SQLITE_VERSION_NUMBER>=3008012
#ifndef SQLITE_CORE
  if( sqlite3_libversion_number()>=3008012 )
#endif
  {
    pIdxInfo->idxFlags |= SQLITE_INDEX_SCAN_UNIQUE;
  }
#endif
}

static void fts5SetEstimatedRows(sqlite3_index_info *pIdxInfo, i64 nRow){
#if SQLITE_VERSION_NUMBER>=3008002
#ifndef SQLITE_CORE
  if( sqlite3_libversion_number()>=3008002 )
#endif
  {
    pIdxInfo->estimatedRows = nRow;
  }
#endif
}

static int fts5UsePatternMatch(
  Fts5Config *pConfig,
  struct sqlite3_index_constraint *p
){
  assert( FTS5_PATTERN_GLOB==SQLITE_INDEX_CONSTRAINT_GLOB );
  assert( FTS5_PATTERN_LIKE==SQLITE_INDEX_CONSTRAINT_LIKE );
  if( pConfig->t.ePattern==FTS5_PATTERN_GLOB && p->op==FTS5_PATTERN_GLOB ){
    return 1;
  }
  if( pConfig->t.ePattern==FTS5_PATTERN_LIKE
   && (p->op==FTS5_PATTERN_LIKE || p->op==FTS5_PATTERN_GLOB)
  ){
    return 1;
  }
  return 0;
}

/*
** Implementation of the xBestIndex method for FTS5 tables. Within the
** WHERE constraint, it searches for the following:
**
**   1. A MATCH constraint against the table column.
**   2. A MATCH constraint against the "rank" column.
**   3. A MATCH constraint against some other column.
**   4. An == constraint against the rowid column.
**   5. A < or <= constraint against the rowid column.
**   6. A > or >= constraint against the rowid column.
**

sqlite3.c  view on Meta::CPAN

          bSeenGt = 1;
        }
      }
    }
  }
  idxStr[iIdxStr] = '\0';

  /* Set idxFlags flags for the ORDER BY clause
  **
  ** Note that tokendata=1 tables cannot currently handle "ORDER BY rowid DESC".
  */
  if( pInfo->nOrderBy==1 ){
    int iSort = pInfo->aOrderBy[0].iColumn;
    if( iSort==(pConfig->nCol+1) && nSeenMatch>0 ){
      idxFlags |= FTS5_BI_ORDER_RANK;
    }else if( iSort==-1 && (!pInfo->aOrderBy[0].desc || !pConfig->bTokendata) ){
      idxFlags |= FTS5_BI_ORDER_ROWID;
    }
    if( BitFlagTest(idxFlags, FTS5_BI_ORDER_RANK|FTS5_BI_ORDER_ROWID) ){
      pInfo->orderByConsumed = 1;
      if( pInfo->aOrderBy[0].desc ){
        idxFlags |= FTS5_BI_ORDER_DESC;
      }
    }
  }

  /* Calculate the estimated cost based on the flags set in idxFlags. */
  if( bSeenEq ){
    pInfo->estimatedCost = nSeenMatch ? 1000.0 : 25.0;
    fts5SetUniqueFlag(pInfo);
    fts5SetEstimatedRows(pInfo, 1);
  }else{
    if( bSeenLt && bSeenGt ){
      pInfo->estimatedCost = nSeenMatch ? 5000.0 :   750000.0;
    }else if( bSeenLt || bSeenGt ){
      pInfo->estimatedCost = nSeenMatch ? 7500.0 :  2250000.0;
    }else{
      pInfo->estimatedCost = nSeenMatch ? 10000.0 : 3000000.0;
    }
    for(i=1; i<nSeenMatch; i++){
      pInfo->estimatedCost *= 0.4;
    }
    fts5SetEstimatedRows(pInfo, (i64)(pInfo->estimatedCost / 4.0));
  }

  pInfo->idxNum = idxFlags;
  return SQLITE_OK;
}

static int fts5NewTransaction(Fts5FullTable *pTab){
  Fts5Cursor *pCsr;
  for(pCsr=pTab->pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
    if( pCsr->base.pVtab==(sqlite3_vtab*)pTab ) return SQLITE_OK;
  }
  return sqlite3Fts5StorageReset(pTab->pStorage);
}

/*
** Implementation of xOpen method.
*/
static int fts5OpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
  Fts5FullTable *pTab = (Fts5FullTable*)pVTab;
  Fts5Config *pConfig = pTab->p.pConfig;
  Fts5Cursor *pCsr = 0;           /* New cursor object */
  sqlite3_int64 nByte;            /* Bytes of space to allocate */
  int rc;                         /* Return code */

  rc = fts5NewTransaction(pTab);
  if( rc==SQLITE_OK ){
    nByte = sizeof(Fts5Cursor) + pConfig->nCol * sizeof(int);
    pCsr = (Fts5Cursor*)sqlite3_malloc64(nByte);
    if( pCsr ){
      Fts5Global *pGlobal = pTab->pGlobal;
      memset(pCsr, 0, (size_t)nByte);
      pCsr->aColumnSize = (int*)&pCsr[1];
      pCsr->pNext = pGlobal->pCsr;
      pGlobal->pCsr = pCsr;
      pCsr->iCsrId = ++pGlobal->iNextId;
    }else{
      rc = SQLITE_NOMEM;
    }
  }
  *ppCsr = (sqlite3_vtab_cursor*)pCsr;
  return rc;
}

static int fts5StmtType(Fts5Cursor *pCsr){
  if( pCsr->ePlan==FTS5_PLAN_SCAN ){
    return (pCsr->bDesc) ? FTS5_STMT_SCAN_DESC : FTS5_STMT_SCAN_ASC;
  }
  return FTS5_STMT_LOOKUP;
}

/*
** This function is called after the cursor passed as the only argument
** is moved to point at a different row. It clears all cached data
** specific to the previous row stored by the cursor object.
*/
static void fts5CsrNewrow(Fts5Cursor *pCsr){
  CsrFlagSet(pCsr,
      FTS5CSR_REQUIRE_CONTENT
    | FTS5CSR_REQUIRE_DOCSIZE
    | FTS5CSR_REQUIRE_INST
    | FTS5CSR_REQUIRE_POSLIST
  );
}

static void fts5FreeCursorComponents(Fts5Cursor *pCsr){
  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
  Fts5Auxdata *pData;
  Fts5Auxdata *pNext;

  sqlite3_free(pCsr->aInstIter);
  sqlite3_free(pCsr->aInst);
  if( pCsr->pStmt ){
    int eStmt = fts5StmtType(pCsr);
    sqlite3Fts5StorageStmtRelease(pTab->pStorage, eStmt, pCsr->pStmt);
  }
  if( pCsr->pSorter ){
    Fts5Sorter *pSorter = pCsr->pSorter;
    sqlite3_finalize(pSorter->pStmt);
    sqlite3_free(pSorter);
  }

  if( pCsr->ePlan!=FTS5_PLAN_SOURCE ){
    sqlite3Fts5ExprFree(pCsr->pExpr);
  }

  for(pData=pCsr->pAuxdata; pData; pData=pNext){
    pNext = pData->pNext;
    if( pData->xDelete ) pData->xDelete(pData->pPtr);
    sqlite3_free(pData);
  }

  sqlite3_finalize(pCsr->pRankArgStmt);
  sqlite3_free(pCsr->apRankArg);

  if( CsrFlagTest(pCsr, FTS5CSR_FREE_ZRANK) ){
    sqlite3_free(pCsr->zRank);
    sqlite3_free(pCsr->zRankArgs);
  }

  sqlite3Fts5IndexCloseReader(pTab->p.pIndex);
  memset(&pCsr->ePlan, 0, sizeof(Fts5Cursor) - ((u8*)&pCsr->ePlan - (u8*)pCsr));
}


/*
** Close the cursor.  For additional information see the documentation
** on the xClose method of the virtual table interface.
*/
static int fts5CloseMethod(sqlite3_vtab_cursor *pCursor){
  if( pCursor ){
    Fts5FullTable *pTab = (Fts5FullTable*)(pCursor->pVtab);
    Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
    Fts5Cursor **pp;

    fts5FreeCursorComponents(pCsr);
    /* Remove the cursor from the Fts5Global.pCsr list */
    for(pp=&pTab->pGlobal->pCsr; (*pp)!=pCsr; pp=&(*pp)->pNext);
    *pp = pCsr->pNext;

    sqlite3_free(pCsr);
  }
  return SQLITE_OK;
}

static int fts5SorterNext(Fts5Cursor *pCsr){
  Fts5Sorter *pSorter = pCsr->pSorter;
  int rc;

  rc = sqlite3_step(pSorter->pStmt);
  if( rc==SQLITE_DONE ){
    rc = SQLITE_OK;
    CsrFlagSet(pCsr, FTS5CSR_EOF|FTS5CSR_REQUIRE_CONTENT);
  }else if( rc==SQLITE_ROW ){
    const u8 *a;
    const u8 *aBlob;
    int nBlob;
    int i;
    int iOff = 0;
    rc = SQLITE_OK;

    pSorter->iRowid = sqlite3_column_int64(pSorter->pStmt, 0);
    nBlob = sqlite3_column_bytes(pSorter->pStmt, 1);
    aBlob = a = sqlite3_column_blob(pSorter->pStmt, 1);

    /* nBlob==0 in detail=none mode. */
    if( nBlob>0 ){
      for(i=0; i<(pSorter->nIdx-1); i++){
        int iVal;
        a += fts5GetVarint32(a, iVal);
        iOff += iVal;
        pSorter->aIdx[i] = iOff;
      }
      pSorter->aIdx[i] = &aBlob[nBlob] - a;
      pSorter->aPoslist = a;
    }

    fts5CsrNewrow(pCsr);
  }

  return rc;
}


/*
** Set the FTS5CSR_REQUIRE_RESEEK flag on all FTS5_PLAN_MATCH cursors
** open on table pTab.
*/
static void fts5TripCursors(Fts5FullTable *pTab){
  Fts5Cursor *pCsr;
  for(pCsr=pTab->pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
    if( pCsr->ePlan==FTS5_PLAN_MATCH
     && pCsr->base.pVtab==(sqlite3_vtab*)pTab
    ){
      CsrFlagSet(pCsr, FTS5CSR_REQUIRE_RESEEK);
    }
  }
}

/*
** If the REQUIRE_RESEEK flag is set on the cursor passed as the first
** argument, close and reopen all Fts5IndexIter iterators that the cursor
** is using. Then attempt to move the cursor to a rowid equal to or laster
** (in the cursors sort order - ASC or DESC) than the current rowid.
**
** If the new rowid is not equal to the old, set output parameter *pbSkip
** to 1 before returning. Otherwise, leave it unchanged.
**
** Return SQLITE_OK if successful or if no reseek was required, or an
** error code if an error occurred.
*/
static int fts5CursorReseek(Fts5Cursor *pCsr, int *pbSkip){
  int rc = SQLITE_OK;
  assert( *pbSkip==0 );
  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_RESEEK) ){
    Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
    int bDesc = pCsr->bDesc;
    i64 iRowid = sqlite3Fts5ExprRowid(pCsr->pExpr);

    rc = sqlite3Fts5ExprFirst(
        pCsr->pExpr, pTab->p.pIndex, iRowid, pCsr->iLastRowid, bDesc
    );
    if( rc==SQLITE_OK &&  iRowid!=sqlite3Fts5ExprRowid(pCsr->pExpr) ){
      *pbSkip = 1;
    }

    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_RESEEK);
    fts5CsrNewrow(pCsr);
    if( sqlite3Fts5ExprEof(pCsr->pExpr) ){
      CsrFlagSet(pCsr, FTS5CSR_EOF);
      *pbSkip = 1;
    }
  }
  return rc;
}


/*
** Advance the cursor to the next row in the table that matches the
** search criteria.
**
** Return SQLITE_OK if nothing goes wrong.  SQLITE_OK is returned
** even if we reach end-of-file.  The fts5EofMethod() will be called
** subsequently to determine whether or not an EOF was hit.
*/
static int fts5NextMethod(sqlite3_vtab_cursor *pCursor){
  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
  int rc;

  assert( (pCsr->ePlan<3)==
          (pCsr->ePlan==FTS5_PLAN_MATCH || pCsr->ePlan==FTS5_PLAN_SOURCE)
  );
  assert( !CsrFlagTest(pCsr, FTS5CSR_EOF) );

  /* If this cursor uses FTS5_PLAN_MATCH and this is a tokendata=1 table,
  ** clear any token mappings accumulated at the fts5_index.c level. In
  ** other cases, specifically FTS5_PLAN_SOURCE and FTS5_PLAN_SORTED_MATCH,
  ** we need to retain the mappings for the entire query.  */
  if( pCsr->ePlan==FTS5_PLAN_MATCH
   && ((Fts5Table*)pCursor->pVtab)->pConfig->bTokendata
  ){
    sqlite3Fts5ExprClearTokens(pCsr->pExpr);
  }

  if( pCsr->ePlan<3 ){
    int bSkip = 0;
    if( (rc = fts5CursorReseek(pCsr, &bSkip)) || bSkip ) return rc;
    rc = sqlite3Fts5ExprNext(pCsr->pExpr, pCsr->iLastRowid);
    CsrFlagSet(pCsr, sqlite3Fts5ExprEof(pCsr->pExpr));
    fts5CsrNewrow(pCsr);
  }else{
    switch( pCsr->ePlan ){
      case FTS5_PLAN_SPECIAL: {
        CsrFlagSet(pCsr, FTS5CSR_EOF);
        rc = SQLITE_OK;
        break;
      }

      case FTS5_PLAN_SORTED_MATCH: {
        rc = fts5SorterNext(pCsr);
        break;
      }

      default: {
        Fts5Config *pConfig = ((Fts5Table*)pCursor->pVtab)->pConfig;
        pConfig->bLock++;
        rc = sqlite3_step(pCsr->pStmt);
        pConfig->bLock--;
        if( rc!=SQLITE_ROW ){
          CsrFlagSet(pCsr, FTS5CSR_EOF);
          rc = sqlite3_reset(pCsr->pStmt);
          if( rc!=SQLITE_OK ){
            pCursor->pVtab->zErrMsg = sqlite3_mprintf(
                "%s", sqlite3_errmsg(pConfig->db)
            );
          }
        }else{
          rc = SQLITE_OK;
          CsrFlagSet(pCsr, FTS5CSR_REQUIRE_DOCSIZE);
        }
        break;
      }
    }
  }

  return rc;
}


static int fts5PrepareStatement(
  sqlite3_stmt **ppStmt,
  Fts5Config *pConfig,
  const char *zFmt,
  ...
){

sqlite3.c  view on Meta::CPAN

  *pnLoc = nLoc - FTS5_LOCALE_HDR_SIZE;

  *ppText = &p[nLoc+1];
  *pnText = n - nLoc - 1;
  return SQLITE_OK;
}

/*
** Argument pVal is the text of a full-text search expression. It may or
** may not have been wrapped by fts5_locale(). This function extracts
** the text of the expression, and sets output variable (*pzText) to
** point to a nul-terminated buffer containing the expression.
**
** If pVal was an fts5_locale() value, then sqlite3Fts5SetLocale() is called
** to set the tokenizer to use the specified locale.
**
** If output variable (*pbFreeAndReset) is set to true, then the caller
** is required to (a) call sqlite3Fts5ClearLocale() to reset the tokenizer
** locale, and (b) call sqlite3_free() to free (*pzText).
*/
static int fts5ExtractExprText(
  Fts5Config *pConfig,            /* Fts5 configuration */
  sqlite3_value *pVal,            /* Value to extract expression text from */
  char **pzText,                  /* OUT: nul-terminated buffer of text */
  int *pbFreeAndReset             /* OUT: Free (*pzText) and clear locale */
){
  int rc = SQLITE_OK;

  if( sqlite3Fts5IsLocaleValue(pConfig, pVal) ){
    const char *pText = 0;
    int nText = 0;
    const char *pLoc = 0;
    int nLoc = 0;
    rc = sqlite3Fts5DecodeLocaleValue(pVal, &pText, &nText, &pLoc, &nLoc);
    *pzText = sqlite3Fts5Mprintf(&rc, "%.*s", nText, pText);
    if( rc==SQLITE_OK ){
      sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
    }
    *pbFreeAndReset = 1;
  }else{
    *pzText = (char*)sqlite3_value_text(pVal);
    *pbFreeAndReset = 0;
  }

  return rc;
}


/*
** This is the xFilter interface for the virtual table.  See
** the virtual table xFilter method documentation for additional
** information.
**
** There are three possible query strategies:
**
**   1. Full-text search using a MATCH operator.
**   2. A by-rowid lookup.
**   3. A full-table scan.
*/
static int fts5FilterMethod(
  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
  int idxNum,                     /* Strategy index */
  const char *idxStr,             /* Unused */
  int nVal,                       /* Number of elements in apVal */
  sqlite3_value **apVal           /* Arguments for the indexing scheme */
){
  Fts5FullTable *pTab = (Fts5FullTable*)(pCursor->pVtab);
  Fts5Config *pConfig = pTab->p.pConfig;
  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
  int rc = SQLITE_OK;             /* Error code */
  int bDesc;                      /* True if ORDER BY [rank|rowid] DESC */
  int bOrderByRank;               /* True if ORDER BY rank */
  sqlite3_value *pRank = 0;       /* rank MATCH ? expression (or NULL) */
  sqlite3_value *pRowidEq = 0;    /* rowid = ? expression (or NULL) */
  sqlite3_value *pRowidLe = 0;    /* rowid <= ? expression (or NULL) */
  sqlite3_value *pRowidGe = 0;    /* rowid >= ? expression (or NULL) */
  int iCol;                       /* Column on LHS of MATCH operator */
  char **pzErrmsg = pConfig->pzErrmsg;
  int bPrefixInsttoken = pConfig->bPrefixInsttoken;
  int i;
  int iIdxStr = 0;
  Fts5Expr *pExpr = 0;

  assert( pConfig->bLock==0 );
  if( pCsr->ePlan ){
    fts5FreeCursorComponents(pCsr);
    memset(&pCsr->ePlan, 0, sizeof(Fts5Cursor) - ((u8*)&pCsr->ePlan-(u8*)pCsr));
  }

  assert( pCsr->pStmt==0 );
  assert( pCsr->pExpr==0 );
  assert( pCsr->csrflags==0 );
  assert( pCsr->pRank==0 );
  assert( pCsr->zRank==0 );
  assert( pCsr->zRankArgs==0 );
  assert( pTab->pSortCsr==0 || nVal==0 );

  assert( pzErrmsg==0 || pzErrmsg==&pTab->p.base.zErrMsg );
  pConfig->pzErrmsg = &pTab->p.base.zErrMsg;

  /* Decode the arguments passed through to this function. */
  for(i=0; i<nVal; i++){
    switch( idxStr[iIdxStr++] ){
      case 'r':
        pRank = apVal[i];
        break;
      case 'M': {
        char *zText = 0;
        int bFreeAndReset = 0;
        int bInternal = 0;

        rc = fts5ExtractExprText(pConfig, apVal[i], &zText, &bFreeAndReset);
        if( rc!=SQLITE_OK ) goto filter_out;
        if( zText==0 ) zText = "";
        if( sqlite3_value_subtype(apVal[i])==FTS5_INSTTOKEN_SUBTYPE ){
          pConfig->bPrefixInsttoken = 1;
        }

        iCol = 0;
        do{
          iCol = iCol*10 + (idxStr[iIdxStr]-'0');
          iIdxStr++;
        }while( idxStr[iIdxStr]>='0' && idxStr[iIdxStr]<='9' );

        if( zText[0]=='*' ){
          /* The user has issued a query of the form "MATCH '*...'". This
          ** indicates that the MATCH expression is not a full text query,
          ** but a request for an internal parameter.  */
          rc = fts5SpecialMatch(pTab, pCsr, &zText[1]);
          bInternal = 1;
        }else{
          char **pzErr = &pTab->p.base.zErrMsg;
          rc = sqlite3Fts5ExprNew(pConfig, 0, iCol, zText, &pExpr, pzErr);
          if( rc==SQLITE_OK ){
            rc = sqlite3Fts5ExprAnd(&pCsr->pExpr, pExpr);
            pExpr = 0;
          }
        }

        if( bFreeAndReset ){
          sqlite3_free(zText);
          sqlite3Fts5ClearLocale(pConfig);
        }

        if( bInternal || rc!=SQLITE_OK ) goto filter_out;

        break;
      }
      case 'L':
      case 'G': {
        int bGlob = (idxStr[iIdxStr-1]=='G');
        const char *zText = (const char*)sqlite3_value_text(apVal[i]);
        iCol = 0;
        do{
          iCol = iCol*10 + (idxStr[iIdxStr]-'0');
          iIdxStr++;
        }while( idxStr[iIdxStr]>='0' && idxStr[iIdxStr]<='9' );
        if( zText ){
          rc = sqlite3Fts5ExprPattern(pConfig, bGlob, iCol, zText, &pExpr);
        }
        if( rc==SQLITE_OK ){
          rc = sqlite3Fts5ExprAnd(&pCsr->pExpr, pExpr);
          pExpr = 0;
        }
        if( rc!=SQLITE_OK ) goto filter_out;
        break;
      }
      case '=':
        pRowidEq = apVal[i];
        break;
      case '<':
        pRowidLe = apVal[i];
        break;
      default: assert( idxStr[iIdxStr-1]=='>' );
        pRowidGe = apVal[i];
        break;
    }
  }
  bOrderByRank = ((idxNum & FTS5_BI_ORDER_RANK) ? 1 : 0);
  pCsr->bDesc = bDesc = ((idxNum & FTS5_BI_ORDER_DESC) ? 1 : 0);

  /* Set the cursor upper and lower rowid limits. Only some strategies
  ** actually use them. This is ok, as the xBestIndex() method leaves the
  ** sqlite3_index_constraint.omit flag clear for range constraints
  ** on the rowid field.  */
  if( pRowidEq ){
    pRowidLe = pRowidGe = pRowidEq;
  }
  if( bDesc ){
    pCsr->iFirstRowid = fts5GetRowidLimit(pRowidLe, LARGEST_INT64);
    pCsr->iLastRowid = fts5GetRowidLimit(pRowidGe, SMALLEST_INT64);
  }else{
    pCsr->iLastRowid = fts5GetRowidLimit(pRowidLe, LARGEST_INT64);
    pCsr->iFirstRowid = fts5GetRowidLimit(pRowidGe, SMALLEST_INT64);
  }

  rc = sqlite3Fts5IndexLoadConfig(pTab->p.pIndex);
  if( rc!=SQLITE_OK ) goto filter_out;

  if( pTab->pSortCsr ){
    /* If pSortCsr is non-NULL, then this call is being made as part of
    ** processing for a "... MATCH <expr> ORDER BY rank" query (ePlan is
    ** set to FTS5_PLAN_SORTED_MATCH). pSortCsr is the cursor that will
    ** return results to the user for this query. The current cursor
    ** (pCursor) is used to execute the query issued by function
    ** fts5CursorFirstSorted() above.  */
    assert( pRowidEq==0 && pRowidLe==0 && pRowidGe==0 && pRank==0 );
    assert( nVal==0 && bOrderByRank==0 && bDesc==0 );
    assert( pCsr->iLastRowid==LARGEST_INT64 );
    assert( pCsr->iFirstRowid==SMALLEST_INT64 );
    if( pTab->pSortCsr->bDesc ){
      pCsr->iLastRowid = pTab->pSortCsr->iFirstRowid;
      pCsr->iFirstRowid = pTab->pSortCsr->iLastRowid;
    }else{
      pCsr->iLastRowid = pTab->pSortCsr->iLastRowid;
      pCsr->iFirstRowid = pTab->pSortCsr->iFirstRowid;
    }
    pCsr->ePlan = FTS5_PLAN_SOURCE;
    pCsr->pExpr = pTab->pSortCsr->pExpr;
    rc = fts5CursorFirst(pTab, pCsr, bDesc);
  }else if( pCsr->pExpr ){
    assert( rc==SQLITE_OK );
    rc = fts5CursorParseRank(pConfig, pCsr, pRank);
    if( rc==SQLITE_OK ){
      if( bOrderByRank ){
        pCsr->ePlan = FTS5_PLAN_SORTED_MATCH;
        rc = fts5CursorFirstSorted(pTab, pCsr, bDesc);
      }else{
        pCsr->ePlan = FTS5_PLAN_MATCH;
        rc = fts5CursorFirst(pTab, pCsr, bDesc);
      }
    }
  }else if( pConfig->zContent==0 ){
    fts5SetVtabError(pTab,"%s: table does not support scanning",pConfig->zName);
    rc = SQLITE_ERROR;
  }else{
    /* This is either a full-table scan (ePlan==FTS5_PLAN_SCAN) or a lookup
    ** by rowid (ePlan==FTS5_PLAN_ROWID).  */
    pCsr->ePlan = (pRowidEq ? FTS5_PLAN_ROWID : FTS5_PLAN_SCAN);
    rc = sqlite3Fts5StorageStmt(
        pTab->pStorage, fts5StmtType(pCsr), &pCsr->pStmt, &pTab->p.base.zErrMsg
    );
    if( rc==SQLITE_OK ){
      if( pRowidEq!=0 ){
        assert( pCsr->ePlan==FTS5_PLAN_ROWID );
        sqlite3_bind_value(pCsr->pStmt, 1, pRowidEq);
      }else{
        sqlite3_bind_int64(pCsr->pStmt, 1, pCsr->iFirstRowid);
        sqlite3_bind_int64(pCsr->pStmt, 2, pCsr->iLastRowid);
      }
      rc = fts5NextMethod(pCursor);
    }
  }

 filter_out:
  sqlite3Fts5ExprFree(pExpr);
  pConfig->pzErrmsg = pzErrmsg;
  pConfig->bPrefixInsttoken = bPrefixInsttoken;
  return rc;
}

/*
** This is the xEof method of the virtual table. SQLite calls this
** routine to find out if it has reached the end of a result set.
*/
static int fts5EofMethod(sqlite3_vtab_cursor *pCursor){
  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
  return (CsrFlagTest(pCsr, FTS5CSR_EOF) ? 1 : 0);
}

/*
** Return the rowid that the cursor currently points to.
*/
static i64 fts5CursorRowid(Fts5Cursor *pCsr){
  assert( pCsr->ePlan==FTS5_PLAN_MATCH
       || pCsr->ePlan==FTS5_PLAN_SORTED_MATCH
       || pCsr->ePlan==FTS5_PLAN_SOURCE
       || pCsr->ePlan==FTS5_PLAN_SCAN
       || pCsr->ePlan==FTS5_PLAN_ROWID
  );
  if( pCsr->pSorter ){
    return pCsr->pSorter->iRowid;
  }else if( pCsr->ePlan>=FTS5_PLAN_SCAN ){
    return sqlite3_column_int64(pCsr->pStmt, 0);
  }else{
    return sqlite3Fts5ExprRowid(pCsr->pExpr);
  }
}

/*
** This is the xRowid method. The SQLite core calls this routine to
** retrieve the rowid for the current row of the result set. fts5
** exposes %_content.rowid as the rowid for the virtual table. The
** rowid should be written to *pRowid.
*/
static int fts5RowidMethod(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
  int ePlan = pCsr->ePlan;

  assert( CsrFlagTest(pCsr, FTS5CSR_EOF)==0 );
  if( ePlan==FTS5_PLAN_SPECIAL ){
    *pRowid = 0;
  }else{
    *pRowid = fts5CursorRowid(pCsr);
  }

  return SQLITE_OK;
}


/*
** If the cursor requires seeking (bSeekRequired flag is set), seek it.
** Return SQLITE_OK if no error occurs, or an SQLite error code otherwise.
**
** If argument bErrormsg is true and an error occurs, an error message may
** be left in sqlite3_vtab.zErrMsg.
*/
static int fts5SeekCursor(Fts5Cursor *pCsr, int bErrormsg){
  int rc = SQLITE_OK;

  /* If the cursor does not yet have a statement handle, obtain one now. */
  if( pCsr->pStmt==0 ){
    Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
    int eStmt = fts5StmtType(pCsr);
    rc = sqlite3Fts5StorageStmt(
        pTab->pStorage, eStmt, &pCsr->pStmt, (bErrormsg?&pTab->p.base.zErrMsg:0)
    );
    assert( rc!=SQLITE_OK || pTab->p.base.zErrMsg==0 );
    assert( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_CONTENT) );
  }

  if( rc==SQLITE_OK && CsrFlagTest(pCsr, FTS5CSR_REQUIRE_CONTENT) ){
    Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);
    assert( pCsr->pExpr );
    sqlite3_reset(pCsr->pStmt);
    sqlite3_bind_int64(pCsr->pStmt, 1, fts5CursorRowid(pCsr));
    pTab->pConfig->bLock++;
    rc = sqlite3_step(pCsr->pStmt);
    pTab->pConfig->bLock--;
    if( rc==SQLITE_ROW ){
      rc = SQLITE_OK;
      CsrFlagClear(pCsr, FTS5CSR_REQUIRE_CONTENT);
    }else{
      rc = sqlite3_reset(pCsr->pStmt);
      if( rc==SQLITE_OK ){
        rc = FTS5_CORRUPT;
        fts5SetVtabError((Fts5FullTable*)pTab,
            "fts5: missing row %lld from content table %s",
            fts5CursorRowid(pCsr),
            pTab->pConfig->zContent
        );
      }else if( pTab->pConfig->pzErrmsg ){
        fts5SetVtabError((Fts5FullTable*)pTab,
            "%s", sqlite3_errmsg(pTab->pConfig->db)
        );
      }
    }
  }
  return rc;
}

/*
** This function is called to handle an FTS INSERT command. In other words,
** an INSERT statement of the form:
**
**     INSERT INTO fts(fts) VALUES($pCmd)
**     INSERT INTO fts(fts, rank) VALUES($pCmd, $pVal)
**
** Argument pVal is the value assigned to column "fts" by the INSERT
** statement. This function returns SQLITE_OK if successful, or an SQLite
** error code if an error occurs.
**
** The commands implemented by this function are documented in the "Special
** INSERT Directives" section of the documentation. It should be updated if
** more commands are added to this function.
*/
static int fts5SpecialInsert(
  Fts5FullTable *pTab,            /* Fts5 table object */
  const char *zCmd,               /* Text inserted into table-name column */
  sqlite3_value *pVal             /* Value inserted into rank column */
){

sqlite3.c  view on Meta::CPAN

  }

  if( bSeenIndex==0 && bRowidModified==0 ){
    *pbContent = 1;
  }else{
    if( bSeenIndexNC || pConfig->bContentlessDelete==0 ){
      rc = SQLITE_ERROR;
      sqlite3Fts5ConfigErrmsg(pConfig,
          (pConfig->bContentlessDelete ?
          "%s a subset of columns on fts5 contentless-delete table: %s" :
          "%s contentless fts5 table: %s")
          , "cannot UPDATE", pConfig->zName
      );
    }
  }

  return rc;
}

/*
** This function is the implementation of the xUpdate callback used by
** FTS3 virtual tables. It is invoked by SQLite each time a row is to be
** inserted, updated or deleted.
**
** A delete specifies a single argument - the rowid of the row to remove.
**
** Update and insert operations pass:
**
**   1. The "old" rowid, or NULL.
**   2. The "new" rowid.
**   3. Values for each of the nCol matchable columns.
**   4. Values for the two hidden columns (<tablename> and "rank").
*/
static int fts5UpdateMethod(
  sqlite3_vtab *pVtab,            /* Virtual table handle */
  int nArg,                       /* Size of argument array */
  sqlite3_value **apVal,          /* Array of arguments */
  sqlite_int64 *pRowid            /* OUT: The affected (or effected) rowid */
){
  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
  Fts5Config *pConfig = pTab->p.pConfig;
  int eType0;                     /* value_type() of apVal[0] */
  int rc = SQLITE_OK;             /* Return code */

  /* A transaction must be open when this is called. */
  assert( pTab->ts.eState==1 || pTab->ts.eState==2 );

  assert( pVtab->zErrMsg==0 );
  assert( nArg==1 || nArg==(2+pConfig->nCol+2) );
  assert( sqlite3_value_type(apVal[0])==SQLITE_INTEGER
       || sqlite3_value_type(apVal[0])==SQLITE_NULL
  );
  assert( pTab->p.pConfig->pzErrmsg==0 );
  if( pConfig->pgsz==0 ){
    rc = sqlite3Fts5ConfigLoad(pTab->p.pConfig, pTab->p.pConfig->iCookie);
    if( rc!=SQLITE_OK ) return rc;
  }

  pTab->p.pConfig->pzErrmsg = &pTab->p.base.zErrMsg;

  /* Put any active cursors into REQUIRE_SEEK state. */
  fts5TripCursors(pTab);

  eType0 = sqlite3_value_type(apVal[0]);
  if( eType0==SQLITE_NULL
   && sqlite3_value_type(apVal[2+pConfig->nCol])!=SQLITE_NULL
  ){
    /* A "special" INSERT op. These are handled separately. */
    const char *z = (const char*)sqlite3_value_text(apVal[2+pConfig->nCol]);
    if( pConfig->eContent!=FTS5_CONTENT_NORMAL
      && 0==sqlite3_stricmp("delete", z)
    ){
      if( pConfig->bContentlessDelete ){
        fts5SetVtabError(pTab,
            "'delete' may not be used with a contentless_delete=1 table"
        );
        rc = SQLITE_ERROR;
      }else{
        rc = fts5SpecialDelete(pTab, apVal);
      }
    }else{
      rc = fts5SpecialInsert(pTab, z, apVal[2 + pConfig->nCol + 1]);
    }
  }else{
    /* A regular INSERT, UPDATE or DELETE statement. The trick here is that
    ** any conflict on the rowid value must be detected before any
    ** modifications are made to the database file. There are 4 cases:
    **
    **   1) DELETE
    **   2) UPDATE (rowid not modified)
    **   3) UPDATE (rowid modified)
    **   4) INSERT
    **
    ** Cases 3 and 4 may violate the rowid constraint.
    */
    int eConflict = SQLITE_ABORT;
    if( pConfig->eContent==FTS5_CONTENT_NORMAL || pConfig->bContentlessDelete ){
      eConflict = sqlite3_vtab_on_conflict(pConfig->db);
    }

    assert( eType0==SQLITE_INTEGER || eType0==SQLITE_NULL );
    assert( nArg!=1 || eType0==SQLITE_INTEGER );

    /* DELETE */
    if( nArg==1 ){
      /* It is only possible to DELETE from a contentless table if the
      ** contentless_delete=1 flag is set. */
      if( fts5IsContentless(pTab, 1) && pConfig->bContentlessDelete==0 ){
        fts5SetVtabError(pTab,
            "cannot DELETE from contentless fts5 table: %s", pConfig->zName
        );
        rc = SQLITE_ERROR;
      }else{
        i64 iDel = sqlite3_value_int64(apVal[0]);  /* Rowid to delete */
        rc = sqlite3Fts5StorageDelete(pTab->pStorage, iDel, 0, 0);
      }
    }

    /* INSERT or UPDATE */
    else{
      int eType1 = sqlite3_value_numeric_type(apVal[1]);

sqlite3.c  view on Meta::CPAN

  int iCol,
  const char **ppText,
  int *pnText
){
  sqlite3_value *pVal = sqlite3_column_value(pStmt, iCol+1);
  const char *pLoc = 0;
  int nLoc = 0;
  int rc = SQLITE_OK;

  if( pConfig->bLocale
   && pConfig->eContent==FTS5_CONTENT_EXTERNAL
   && sqlite3Fts5IsLocaleValue(pConfig, pVal)
  ){
    rc = sqlite3Fts5DecodeLocaleValue(pVal, ppText, pnText, &pLoc, &nLoc);
  }else{
    *ppText = (const char*)sqlite3_value_text(pVal);
    *pnText = sqlite3_value_bytes(pVal);
    if( pConfig->bLocale && pConfig->eContent==FTS5_CONTENT_NORMAL ){
      pLoc = (const char*)sqlite3_column_text(pStmt, iCol+1+pConfig->nCol);
      nLoc = sqlite3_column_bytes(pStmt, iCol+1+pConfig->nCol);
    }
  }
  sqlite3Fts5SetLocale(pConfig, pLoc, nLoc);
  return rc;
}

static int fts5ApiColumnText(
  Fts5Context *pCtx,
  int iCol,
  const char **pz,
  int *pn
){
  int rc = SQLITE_OK;
  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
  Fts5Table *pTab = (Fts5Table*)(pCsr->base.pVtab);

  assert( pCsr->ePlan!=FTS5_PLAN_SPECIAL );
  if( iCol<0 || iCol>=pTab->pConfig->nCol ){
    rc = SQLITE_RANGE;
  }else if( fts5IsContentless((Fts5FullTable*)(pCsr->base.pVtab), 0) ){
    *pz = 0;
    *pn = 0;
  }else{
    rc = fts5SeekCursor(pCsr, 0);
    if( rc==SQLITE_OK ){
      rc = fts5TextFromStmt(pTab->pConfig, pCsr->pStmt, iCol, pz, pn);
      sqlite3Fts5ClearLocale(pTab->pConfig);
    }
  }
  return rc;
}

/*
** This is called by various API functions - xInst, xPhraseFirst,
** xPhraseFirstColumn etc. - to obtain the position list for phrase iPhrase
** of the current row. This function works for both detail=full tables (in
** which case the position-list was read from the fts index) or for other
** detail= modes if the row content is available.
*/
static int fts5CsrPoslist(
  Fts5Cursor *pCsr,               /* Fts5 cursor object */
  int iPhrase,                    /* Phrase to find position list for */
  const u8 **pa,                  /* OUT: Pointer to position list buffer */
  int *pn                         /* OUT: Size of (*pa) in bytes */
){
  Fts5Config *pConfig = ((Fts5Table*)(pCsr->base.pVtab))->pConfig;
  int rc = SQLITE_OK;
  int bLive = (pCsr->pSorter==0);

  if( iPhrase<0 || iPhrase>=sqlite3Fts5ExprPhraseCount(pCsr->pExpr) ){
    rc = SQLITE_RANGE;
  }else if( pConfig->eDetail!=FTS5_DETAIL_FULL
         && fts5IsContentless((Fts5FullTable*)pCsr->base.pVtab, 1)
  ){
    *pa = 0;
    *pn = 0;
    return SQLITE_OK;
  }else if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_POSLIST) ){
    if( pConfig->eDetail!=FTS5_DETAIL_FULL ){
      Fts5PoslistPopulator *aPopulator;
      int i;

      aPopulator = sqlite3Fts5ExprClearPoslists(pCsr->pExpr, bLive);
      if( aPopulator==0 ) rc = SQLITE_NOMEM;
      if( rc==SQLITE_OK ){
        rc = fts5SeekCursor(pCsr, 0);
      }
      for(i=0; i<pConfig->nCol && rc==SQLITE_OK; i++){
        const char *z = 0;
        int n = 0;
        rc = fts5TextFromStmt(pConfig, pCsr->pStmt, i, &z, &n);
        if( rc==SQLITE_OK ){
          rc = sqlite3Fts5ExprPopulatePoslists(
              pConfig, pCsr->pExpr, aPopulator, i, z, n
          );
        }
        sqlite3Fts5ClearLocale(pConfig);
      }
      sqlite3_free(aPopulator);

      if( pCsr->pSorter ){
        sqlite3Fts5ExprCheckPoslists(pCsr->pExpr, pCsr->pSorter->iRowid);
      }
    }
    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_POSLIST);
  }

  if( rc==SQLITE_OK ){
    if( pCsr->pSorter && pConfig->eDetail==FTS5_DETAIL_FULL ){
      Fts5Sorter *pSorter = pCsr->pSorter;
      int i1 = (iPhrase==0 ? 0 : pSorter->aIdx[iPhrase-1]);
      *pn = pSorter->aIdx[iPhrase] - i1;
      *pa = &pSorter->aPoslist[i1];
    }else{
      *pn = sqlite3Fts5ExprPoslist(pCsr->pExpr, iPhrase, pa);
    }
  }else{
    *pa = 0;
    *pn = 0;
  }

sqlite3.c  view on Meta::CPAN

  Fts5Config *pConfig = pTab->p.pConfig;
  int rc = SQLITE_OK;

  if( CsrFlagTest(pCsr, FTS5CSR_REQUIRE_DOCSIZE) ){
    if( pConfig->bColumnsize ){
      i64 iRowid = fts5CursorRowid(pCsr);
      rc = sqlite3Fts5StorageDocsize(pTab->pStorage, iRowid, pCsr->aColumnSize);
    }else if( !pConfig->zContent || pConfig->eContent==FTS5_CONTENT_UNINDEXED ){
      int i;
      for(i=0; i<pConfig->nCol; i++){
        if( pConfig->abUnindexed[i]==0 ){
          pCsr->aColumnSize[i] = -1;
        }
      }
    }else{
      int i;
      rc = fts5SeekCursor(pCsr, 0);
      for(i=0; rc==SQLITE_OK && i<pConfig->nCol; i++){
        if( pConfig->abUnindexed[i]==0 ){
          const char *z = 0;
          int n = 0;
          pCsr->aColumnSize[i] = 0;
          rc = fts5TextFromStmt(pConfig, pCsr->pStmt, i, &z, &n);
          if( rc==SQLITE_OK ){
            rc = sqlite3Fts5Tokenize(pConfig, FTS5_TOKENIZE_AUX,
                z, n, (void*)&pCsr->aColumnSize[i], fts5ColumnSizeCb
            );
          }
          sqlite3Fts5ClearLocale(pConfig);
        }
      }
    }
    CsrFlagClear(pCsr, FTS5CSR_REQUIRE_DOCSIZE);
  }
  if( iCol<0 ){
    int i;
    *pnToken = 0;
    for(i=0; i<pConfig->nCol; i++){
      *pnToken += pCsr->aColumnSize[i];
    }
  }else if( iCol<pConfig->nCol ){
    *pnToken = pCsr->aColumnSize[iCol];
  }else{
    *pnToken = 0;
    rc = SQLITE_RANGE;
  }
  return rc;
}

/*
** Implementation of the xSetAuxdata() method.
*/
static int fts5ApiSetAuxdata(
  Fts5Context *pCtx,              /* Fts5 context */
  void *pPtr,                     /* Pointer to save as auxdata */
  void(*xDelete)(void*)           /* Destructor for pPtr (or NULL) */
){
  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
  Fts5Auxdata *pData;

  /* Search through the cursors list of Fts5Auxdata objects for one that
  ** corresponds to the currently executing auxiliary function.  */
  for(pData=pCsr->pAuxdata; pData; pData=pData->pNext){
    if( pData->pAux==pCsr->pAux ) break;
  }

  if( pData ){
    if( pData->xDelete ){
      pData->xDelete(pData->pPtr);
    }
  }else{
    int rc = SQLITE_OK;
    pData = (Fts5Auxdata*)sqlite3Fts5MallocZero(&rc, sizeof(Fts5Auxdata));
    if( pData==0 ){
      if( xDelete ) xDelete(pPtr);
      return rc;
    }
    pData->pAux = pCsr->pAux;
    pData->pNext = pCsr->pAuxdata;
    pCsr->pAuxdata = pData;
  }

  pData->xDelete = xDelete;
  pData->pPtr = pPtr;
  return SQLITE_OK;
}

static void *fts5ApiGetAuxdata(Fts5Context *pCtx, int bClear){
  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
  Fts5Auxdata *pData;
  void *pRet = 0;

  for(pData=pCsr->pAuxdata; pData; pData=pData->pNext){
    if( pData->pAux==pCsr->pAux ) break;
  }

  if( pData ){
    pRet = pData->pPtr;
    if( bClear ){
      pData->pPtr = 0;
      pData->xDelete = 0;
    }
  }

  return pRet;
}

static void fts5ApiPhraseNext(
  Fts5Context *pCtx,
  Fts5PhraseIter *pIter,
  int *piCol, int *piOff
){
  if( pIter->a>=pIter->b ){
    *piCol = -1;
    *piOff = -1;
  }else{
    int iVal;
    pIter->a += fts5GetVarint32(pIter->a, iVal);
    if( iVal==1 ){
      /* Avoid returning a (*piCol) value that is too large for the table,
      ** even if the position-list is corrupt. The caller might not be

sqlite3.c  view on Meta::CPAN

   && 0==fts5IsContentless((Fts5FullTable*)pCsr->base.pVtab, 1)
   && pConfig->bLocale
  ){
    rc = fts5SeekCursor(pCsr, 0);
    if( rc==SQLITE_OK ){
      const char *zDummy = 0;
      int nDummy = 0;
      rc = fts5TextFromStmt(pConfig, pCsr->pStmt, iCol, &zDummy, &nDummy);
      if( rc==SQLITE_OK ){
        *pzLocale = pConfig->t.pLocale;
        *pnLocale = pConfig->t.nLocale;
      }
      sqlite3Fts5ClearLocale(pConfig);
    }
  }

  return rc;
}

static const Fts5ExtensionApi sFts5Api = {
  4,                            /* iVersion */
  fts5ApiUserData,
  fts5ApiColumnCount,
  fts5ApiRowCount,
  fts5ApiColumnTotalSize,
  fts5ApiTokenize,
  fts5ApiPhraseCount,
  fts5ApiPhraseSize,
  fts5ApiInstCount,
  fts5ApiInst,
  fts5ApiRowid,
  fts5ApiColumnText,
  fts5ApiColumnSize,
  fts5ApiQueryPhrase,
  fts5ApiSetAuxdata,
  fts5ApiGetAuxdata,
  fts5ApiPhraseFirst,
  fts5ApiPhraseNext,
  fts5ApiPhraseFirstColumn,
  fts5ApiPhraseNextColumn,
  fts5ApiQueryToken,
  fts5ApiInstToken,
  fts5ApiColumnLocale,
  fts5ApiTokenize_v2
};

/*
** Implementation of API function xQueryPhrase().
*/
static int fts5ApiQueryPhrase(
  Fts5Context *pCtx,
  int iPhrase,
  void *pUserData,
  int(*xCallback)(const Fts5ExtensionApi*, Fts5Context*, void*)
){
  Fts5Cursor *pCsr = (Fts5Cursor*)pCtx;
  Fts5FullTable *pTab = (Fts5FullTable*)(pCsr->base.pVtab);
  int rc;
  Fts5Cursor *pNew = 0;

  rc = fts5OpenMethod(pCsr->base.pVtab, (sqlite3_vtab_cursor**)&pNew);
  if( rc==SQLITE_OK ){
    pNew->ePlan = FTS5_PLAN_MATCH;
    pNew->iFirstRowid = SMALLEST_INT64;
    pNew->iLastRowid = LARGEST_INT64;
    pNew->base.pVtab = (sqlite3_vtab*)pTab;
    rc = sqlite3Fts5ExprClonePhrase(pCsr->pExpr, iPhrase, &pNew->pExpr);
  }

  if( rc==SQLITE_OK ){
    for(rc = fts5CursorFirst(pTab, pNew, 0);
        rc==SQLITE_OK && CsrFlagTest(pNew, FTS5CSR_EOF)==0;
        rc = fts5NextMethod((sqlite3_vtab_cursor*)pNew)
    ){
      rc = xCallback(&sFts5Api, (Fts5Context*)pNew, pUserData);
      if( rc!=SQLITE_OK ){
        if( rc==SQLITE_DONE ) rc = SQLITE_OK;
        break;
      }
    }
  }

  fts5CloseMethod((sqlite3_vtab_cursor*)pNew);
  return rc;
}

static void fts5ApiInvoke(
  Fts5Auxiliary *pAux,
  Fts5Cursor *pCsr,
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  assert( pCsr->pAux==0 );
  assert( pCsr->ePlan!=FTS5_PLAN_SPECIAL );
  pCsr->pAux = pAux;
  pAux->xFunc(&sFts5Api, (Fts5Context*)pCsr, context, argc, argv);
  pCsr->pAux = 0;
}

static Fts5Cursor *fts5CursorFromCsrid(Fts5Global *pGlobal, i64 iCsrId){
  Fts5Cursor *pCsr;
  for(pCsr=pGlobal->pCsr; pCsr; pCsr=pCsr->pNext){
    if( pCsr->iCsrId==iCsrId ) break;
  }
  return pCsr;
}

/*
** Parameter zFmt is a printf() style formatting string. This function
** formats it using the trailing arguments and returns the result as
** an error message to the context passed as the first argument.
*/
static void fts5ResultError(sqlite3_context *pCtx, const char *zFmt, ...){
  char *zErr = 0;
  va_list ap;
  va_start(ap, zFmt);
  zErr = sqlite3_vmprintf(zFmt, ap);
  sqlite3_result_error(pCtx, zErr, -1);
  sqlite3_free(zErr);
  va_end(ap);
}

static void fts5ApiCallback(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){

  Fts5Auxiliary *pAux;
  Fts5Cursor *pCsr;
  i64 iCsrId;

  assert( argc>=1 );
  pAux = (Fts5Auxiliary*)sqlite3_user_data(context);
  iCsrId = sqlite3_value_int64(argv[0]);

  pCsr = fts5CursorFromCsrid(pAux->pGlobal, iCsrId);
  if( pCsr==0 || (pCsr->ePlan==0 || pCsr->ePlan==FTS5_PLAN_SPECIAL) ){
    fts5ResultError(context, "no such cursor: %lld", iCsrId);
  }else{
    sqlite3_vtab *pTab = pCsr->base.pVtab;
    fts5ApiInvoke(pAux, pCsr, context, argc-1, &argv[1]);
    sqlite3_free(pTab->zErrMsg);
    pTab->zErrMsg = 0;
  }
}


/*
** Given cursor id iId, return a pointer to the corresponding Fts5Table
** object. Or NULL If the cursor id does not exist.
*/
static Fts5Table *sqlite3Fts5TableFromCsrid(
  Fts5Global *pGlobal,            /* FTS5 global context for db handle */
  i64 iCsrId                      /* Id of cursor to find */
){
  Fts5Cursor *pCsr;
  pCsr = fts5CursorFromCsrid(pGlobal, iCsrId);
  if( pCsr ){
    return (Fts5Table*)pCsr->base.pVtab;
  }
  return 0;
}

/*
** Return a "position-list blob" corresponding to the current position of
** cursor pCsr via sqlite3_result_blob(). A position-list blob contains
** the current position-list for each phrase in the query associated with
** cursor pCsr.
**
** A position-list blob begins with (nPhrase-1) varints, where nPhrase is
** the number of phrases in the query. Following the varints are the
** concatenated position lists for each phrase, in order.
**
** The first varint (if it exists) contains the size of the position list
** for phrase 0. The second (same disclaimer) contains the size of position
** list 1. And so on. There is no size field for the final position list,
** as it can be derived from the total size of the blob.
*/
static int fts5PoslistBlob(sqlite3_context *pCtx, Fts5Cursor *pCsr){
  int i;
  int rc = SQLITE_OK;
  int nPhrase = sqlite3Fts5ExprPhraseCount(pCsr->pExpr);
  Fts5Buffer val;

  memset(&val, 0, sizeof(Fts5Buffer));
  switch( ((Fts5Table*)(pCsr->base.pVtab))->pConfig->eDetail ){
    case FTS5_DETAIL_FULL:

      /* Append the varints */
      for(i=0; i<(nPhrase-1); i++){
        const u8 *dummy;
        int nByte = sqlite3Fts5ExprPoslist(pCsr->pExpr, i, &dummy);
        sqlite3Fts5BufferAppendVarint(&rc, &val, nByte);
      }

      /* Append the position lists */
      for(i=0; i<nPhrase; i++){
        const u8 *pPoslist;
        int nPoslist;
        nPoslist = sqlite3Fts5ExprPoslist(pCsr->pExpr, i, &pPoslist);
        sqlite3Fts5BufferAppendBlob(&rc, &val, nPoslist, pPoslist);
      }
      break;

    case FTS5_DETAIL_COLUMNS:

      /* Append the varints */
      for(i=0; rc==SQLITE_OK && i<(nPhrase-1); i++){
        const u8 *dummy;
        int nByte;
        rc = sqlite3Fts5ExprPhraseCollist(pCsr->pExpr, i, &dummy, &nByte);
        sqlite3Fts5BufferAppendVarint(&rc, &val, nByte);
      }

      /* Append the position lists */
      for(i=0; rc==SQLITE_OK && i<nPhrase; i++){
        const u8 *pPoslist;
        int nPoslist;
        rc = sqlite3Fts5ExprPhraseCollist(pCsr->pExpr, i, &pPoslist, &nPoslist);
        sqlite3Fts5BufferAppendBlob(&rc, &val, nPoslist, pPoslist);
      }
      break;

    default:
      break;
  }

  sqlite3_result_blob(pCtx, val.p, val.n, sqlite3_free);
  return rc;
}

/*
** This is the xColumn method, called by SQLite to request a value from
** the row that the supplied cursor currently points to.
*/
static int fts5ColumnMethod(
  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
  int iCol                        /* Index of column to read value from */
){
  Fts5FullTable *pTab = (Fts5FullTable*)(pCursor->pVtab);
  Fts5Config *pConfig = pTab->p.pConfig;
  Fts5Cursor *pCsr = (Fts5Cursor*)pCursor;
  int rc = SQLITE_OK;

  assert( CsrFlagTest(pCsr, FTS5CSR_EOF)==0 );

  if( pCsr->ePlan==FTS5_PLAN_SPECIAL ){
    if( iCol==pConfig->nCol ){
      sqlite3_result_int64(pCtx, pCsr->iSpecial);
    }
  }else

  if( iCol==pConfig->nCol ){
    /* User is requesting the value of the special column with the same name
    ** as the table. Return the cursor integer id number. This value is only
    ** useful in that it may be passed as the first argument to an FTS5
    ** auxiliary function.  */
    sqlite3_result_int64(pCtx, pCsr->iCsrId);
  }else if( iCol==pConfig->nCol+1 ){
    /* The value of the "rank" column. */

    if( pCsr->ePlan==FTS5_PLAN_SOURCE ){
      fts5PoslistBlob(pCtx, pCsr);
    }else if(
        pCsr->ePlan==FTS5_PLAN_MATCH
     || pCsr->ePlan==FTS5_PLAN_SORTED_MATCH
    ){
      if( pCsr->pRank || SQLITE_OK==(rc = fts5FindRankFunction(pCsr)) ){
        fts5ApiInvoke(pCsr->pRank, pCsr, pCtx, pCsr->nRankArg, pCsr->apRankArg);
      }
    }
  }else{
    if( !sqlite3_vtab_nochange(pCtx) && pConfig->eContent!=FTS5_CONTENT_NONE ){
      pConfig->pzErrmsg = &pTab->p.base.zErrMsg;
      rc = fts5SeekCursor(pCsr, 1);
      if( rc==SQLITE_OK ){
        sqlite3_value *pVal = sqlite3_column_value(pCsr->pStmt, iCol+1);
        if( pConfig->bLocale
         && pConfig->eContent==FTS5_CONTENT_EXTERNAL
         && sqlite3Fts5IsLocaleValue(pConfig, pVal)
        ){
          const char *z = 0;
          int n = 0;
          rc = fts5TextFromStmt(pConfig, pCsr->pStmt, iCol, &z, &n);
          if( rc==SQLITE_OK ){
            sqlite3_result_text(pCtx, z, n, SQLITE_TRANSIENT);
          }
          sqlite3Fts5ClearLocale(pConfig);
        }else{
          sqlite3_result_value(pCtx, pVal);
        }
      }

      pConfig->pzErrmsg = 0;
    }
  }

  return rc;
}


/*
** This routine implements the xFindFunction method for the FTS3
** virtual table.
*/
static int fts5FindFunctionMethod(
  sqlite3_vtab *pVtab,            /* Virtual table handle */
  int nUnused,                    /* Number of SQL function arguments */
  const char *zName,              /* Name of SQL function */
  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), /* OUT: Result */
  void **ppArg                    /* OUT: User data for *pxFunc */
){
  Fts5FullTable *pTab = (Fts5FullTable*)pVtab;
  Fts5Auxiliary *pAux;

sqlite3.c  view on Meta::CPAN

  if( iVal<(1 << 28) ) return 4;
  return 5;
}

/*
** 2015 May 08
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This is an SQLite virtual table module implementing direct access to an
** existing FTS5 index. The module may create several different types of
** tables:
**
** col:
**     CREATE TABLE vocab(term, col, doc, cnt, PRIMARY KEY(term, col));
**
**   One row for each term/column combination. The value of $doc is set to
**   the number of fts5 rows that contain at least one instance of term
**   $term within column $col. Field $cnt is set to the total number of
**   instances of term $term in column $col (in any row of the fts5 table).
**
** row:
**     CREATE TABLE vocab(term, doc, cnt, PRIMARY KEY(term));
**
**   One row for each term in the database. The value of $doc is set to
**   the number of fts5 rows that contain at least one instance of term
**   $term. Field $cnt is set to the total number of instances of term
**   $term in the database.
**
** instance:
**     CREATE TABLE vocab(term, doc, col, offset, PRIMARY KEY(<all-fields>));
**
**   One row for each term instance in the database.
*/


/* #include "fts5Int.h" */


typedef struct Fts5VocabTable Fts5VocabTable;
typedef struct Fts5VocabCursor Fts5VocabCursor;

struct Fts5VocabTable {
  sqlite3_vtab base;
  char *zFts5Tbl;                 /* Name of fts5 table */
  char *zFts5Db;                  /* Db containing fts5 table */
  sqlite3 *db;                    /* Database handle */
  Fts5Global *pGlobal;            /* FTS5 global object for this database */
  int eType;                      /* FTS5_VOCAB_COL, ROW or INSTANCE */
  unsigned bBusy;                 /* True if busy */
};

struct Fts5VocabCursor {
  sqlite3_vtab_cursor base;
  sqlite3_stmt *pStmt;            /* Statement holding lock on pIndex */
  Fts5Table *pFts5;               /* Associated FTS5 table */

  int bEof;                       /* True if this cursor is at EOF */
  Fts5IndexIter *pIter;           /* Term/rowid iterator object */
  void *pStruct;                  /* From sqlite3Fts5StructureRef() */

  int nLeTerm;                    /* Size of zLeTerm in bytes */
  char *zLeTerm;                  /* (term <= $zLeTerm) paramater, or NULL */
  int colUsed;                    /* Copy of sqlite3_index_info.colUsed */

  /* These are used by 'col' tables only */
  int iCol;
  i64 *aCnt;
  i64 *aDoc;

  /* Output values used by all tables. */
  i64 rowid;                      /* This table's current rowid value */
  Fts5Buffer term;                /* Current value of 'term' column */

  /* Output values Used by 'instance' tables only */
  i64 iInstPos;
  int iInstOff;
};

#define FTS5_VOCAB_COL      0
#define FTS5_VOCAB_ROW      1
#define FTS5_VOCAB_INSTANCE 2

#define FTS5_VOCAB_COL_SCHEMA  "term, col, doc, cnt"
#define FTS5_VOCAB_ROW_SCHEMA  "term, doc, cnt"
#define FTS5_VOCAB_INST_SCHEMA "term, doc, col, offset"

/*
** Bits for the mask used as the idxNum value by xBestIndex/xFilter.
*/
#define FTS5_VOCAB_TERM_EQ 0x0100
#define FTS5_VOCAB_TERM_GE 0x0200
#define FTS5_VOCAB_TERM_LE 0x0400

#define FTS5_VOCAB_COLUSED_MASK 0xFF


/*
** Translate a string containing an fts5vocab table type to an
** FTS5_VOCAB_XXX constant. If successful, set *peType to the output
** value and return SQLITE_OK. Otherwise, set *pzErr to an error message
** and return SQLITE_ERROR.
*/
static int fts5VocabTableType(const char *zType, char **pzErr, int *peType){
  int rc = SQLITE_OK;
  char *zCopy = sqlite3Fts5Strndup(&rc, zType, -1);
  if( rc==SQLITE_OK ){
    sqlite3Fts5Dequote(zCopy);
    if( sqlite3_stricmp(zCopy, "col")==0 ){
      *peType = FTS5_VOCAB_COL;
    }else

    if( sqlite3_stricmp(zCopy, "row")==0 ){
      *peType = FTS5_VOCAB_ROW;
    }else
    if( sqlite3_stricmp(zCopy, "instance")==0 ){
      *peType = FTS5_VOCAB_INSTANCE;
    }else

sqlite3.c  view on Meta::CPAN

  int iTermGe = -1;
  int iTermLe = -1;
  int idxNum = (int)pInfo->colUsed;
  int nArg = 0;

  UNUSED_PARAM(pUnused);

  assert( (pInfo->colUsed & FTS5_VOCAB_COLUSED_MASK)==pInfo->colUsed );

  for(i=0; i<pInfo->nConstraint; i++){
    struct sqlite3_index_constraint *p = &pInfo->aConstraint[i];
    if( p->usable==0 ) continue;
    if( p->iColumn==0 ){          /* term column */
      if( p->op==SQLITE_INDEX_CONSTRAINT_EQ ) iTermEq = i;
      if( p->op==SQLITE_INDEX_CONSTRAINT_LE ) iTermLe = i;
      if( p->op==SQLITE_INDEX_CONSTRAINT_LT ) iTermLe = i;
      if( p->op==SQLITE_INDEX_CONSTRAINT_GE ) iTermGe = i;
      if( p->op==SQLITE_INDEX_CONSTRAINT_GT ) iTermGe = i;
    }
  }

  if( iTermEq>=0 ){
    idxNum |= FTS5_VOCAB_TERM_EQ;
    pInfo->aConstraintUsage[iTermEq].argvIndex = ++nArg;
    pInfo->estimatedCost = 100;
  }else{
    pInfo->estimatedCost = 1000000;
    if( iTermGe>=0 ){
      idxNum |= FTS5_VOCAB_TERM_GE;
      pInfo->aConstraintUsage[iTermGe].argvIndex = ++nArg;
      pInfo->estimatedCost = pInfo->estimatedCost / 2;
    }
    if( iTermLe>=0 ){
      idxNum |= FTS5_VOCAB_TERM_LE;
      pInfo->aConstraintUsage[iTermLe].argvIndex = ++nArg;
      pInfo->estimatedCost = pInfo->estimatedCost / 2;
    }
  }

  /* This virtual table always delivers results in ascending order of
  ** the "term" column (column 0). So if the user has requested this
  ** specifically - "ORDER BY term" or "ORDER BY term ASC" - set the
  ** sqlite3_index_info.orderByConsumed flag to tell the core the results
  ** are already in sorted order.  */
  if( pInfo->nOrderBy==1
   && pInfo->aOrderBy[0].iColumn==0
   && pInfo->aOrderBy[0].desc==0
  ){
    pInfo->orderByConsumed = 1;
  }

  pInfo->idxNum = idxNum;
  return SQLITE_OK;
}

/*
** Implementation of xOpen method.
*/
static int fts5VocabOpenMethod(
  sqlite3_vtab *pVTab,
  sqlite3_vtab_cursor **ppCsr
){
  Fts5VocabTable *pTab = (Fts5VocabTable*)pVTab;
  Fts5Table *pFts5 = 0;
  Fts5VocabCursor *pCsr = 0;
  int rc = SQLITE_OK;
  sqlite3_stmt *pStmt = 0;
  char *zSql = 0;

  if( pTab->bBusy ){
    pVTab->zErrMsg = sqlite3_mprintf(
       "recursive definition for %s.%s", pTab->zFts5Db, pTab->zFts5Tbl
    );
    return SQLITE_ERROR;
  }
  zSql = sqlite3Fts5Mprintf(&rc,
      "SELECT t.%Q FROM %Q.%Q AS t WHERE t.%Q MATCH '*id'",
      pTab->zFts5Tbl, pTab->zFts5Db, pTab->zFts5Tbl, pTab->zFts5Tbl
  );
  if( zSql ){
    rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pStmt, 0);
  }
  sqlite3_free(zSql);
  assert( rc==SQLITE_OK || pStmt==0 );
  if( rc==SQLITE_ERROR ) rc = SQLITE_OK;

  pTab->bBusy = 1;
  if( pStmt && sqlite3_step(pStmt)==SQLITE_ROW ){
    i64 iId = sqlite3_column_int64(pStmt, 0);
    pFts5 = sqlite3Fts5TableFromCsrid(pTab->pGlobal, iId);
  }
  pTab->bBusy = 0;

  if( rc==SQLITE_OK ){
    if( pFts5==0 ){
      rc = sqlite3_finalize(pStmt);
      pStmt = 0;
      if( rc==SQLITE_OK ){
        pVTab->zErrMsg = sqlite3_mprintf(
            "no such fts5 table: %s.%s", pTab->zFts5Db, pTab->zFts5Tbl
        );
        rc = SQLITE_ERROR;
      }
    }else{
      rc = sqlite3Fts5FlushToDisk(pFts5);
    }
  }

  if( rc==SQLITE_OK ){
    i64 nByte = pFts5->pConfig->nCol * sizeof(i64)*2 + sizeof(Fts5VocabCursor);
    pCsr = (Fts5VocabCursor*)sqlite3Fts5MallocZero(&rc, nByte);
  }

  if( pCsr ){
    pCsr->pFts5 = pFts5;
    pCsr->pStmt = pStmt;
    pCsr->aCnt = (i64*)&pCsr[1];
    pCsr->aDoc = &pCsr->aCnt[pFts5->pConfig->nCol];
  }else{
    sqlite3_finalize(pStmt);
  }

  *ppCsr = (sqlite3_vtab_cursor*)pCsr;
  return rc;
}

/*
** Restore cursor pCsr to the state it was in immediately after being
** created by the xOpen() method.
*/
static void fts5VocabResetCursor(Fts5VocabCursor *pCsr){
  int nCol = pCsr->pFts5->pConfig->nCol;
  pCsr->rowid = 0;
  sqlite3Fts5IterClose(pCsr->pIter);
  sqlite3Fts5StructureRelease(pCsr->pStruct);
  pCsr->pStruct = 0;
  pCsr->pIter = 0;
  sqlite3_free(pCsr->zLeTerm);
  pCsr->nLeTerm = -1;
  pCsr->zLeTerm = 0;
  pCsr->bEof = 0;
  pCsr->iCol = 0;
  pCsr->iInstPos = 0;
  pCsr->iInstOff = 0;
  pCsr->colUsed = 0;
  memset(pCsr->aCnt, 0, sizeof(i64)*nCol);
  memset(pCsr->aDoc, 0, sizeof(i64)*nCol);
}

/*
** Close the cursor.  For additional information see the documentation
** on the xClose method of the virtual table interface.
*/
static int fts5VocabCloseMethod(sqlite3_vtab_cursor *pCursor){
  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
  fts5VocabResetCursor(pCsr);
  sqlite3Fts5BufferFree(&pCsr->term);
  sqlite3_finalize(pCsr->pStmt);
  sqlite3_free(pCsr);
  return SQLITE_OK;
}

static int fts5VocabInstanceNewTerm(Fts5VocabCursor *pCsr){
  int rc = SQLITE_OK;

  if( sqlite3Fts5IterEof(pCsr->pIter) ){
    pCsr->bEof = 1;
  }else{
    const char *zTerm;
    int nTerm;
    zTerm = sqlite3Fts5IterTerm(pCsr->pIter, &nTerm);
    if( pCsr->nLeTerm>=0 ){
      int nCmp = MIN(nTerm, pCsr->nLeTerm);
      int bCmp = memcmp(pCsr->zLeTerm, zTerm, nCmp);
      if( bCmp<0 || (bCmp==0 && pCsr->nLeTerm<nTerm) ){
        pCsr->bEof = 1;
      }
    }

    sqlite3Fts5BufferSet(&rc, &pCsr->term, nTerm, (const u8*)zTerm);
  }
  return rc;
}

static int fts5VocabInstanceNext(Fts5VocabCursor *pCsr){
  int eDetail = pCsr->pFts5->pConfig->eDetail;
  int rc = SQLITE_OK;
  Fts5IndexIter *pIter = pCsr->pIter;
  i64 *pp = &pCsr->iInstPos;
  int *po = &pCsr->iInstOff;

  assert( sqlite3Fts5IterEof(pIter)==0 );
  assert( pCsr->bEof==0 );
  while( eDetail==FTS5_DETAIL_NONE
      || sqlite3Fts5PoslistNext64(pIter->pData, pIter->nData, po, pp)
  ){
    pCsr->iInstPos = 0;
    pCsr->iInstOff = 0;

    rc = sqlite3Fts5IterNextScan(pCsr->pIter);
    if( rc==SQLITE_OK ){
      rc = fts5VocabInstanceNewTerm(pCsr);
      if( pCsr->bEof || eDetail==FTS5_DETAIL_NONE ) break;
    }
    if( rc ){
      pCsr->bEof = 1;
      break;
    }
  }

  return rc;
}

/*
** Advance the cursor to the next row in the table.
*/
static int fts5VocabNextMethod(sqlite3_vtab_cursor *pCursor){
  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
  Fts5VocabTable *pTab = (Fts5VocabTable*)pCursor->pVtab;
  int nCol = pCsr->pFts5->pConfig->nCol;
  int rc;

  rc = sqlite3Fts5StructureTest(pCsr->pFts5->pIndex, pCsr->pStruct);
  if( rc!=SQLITE_OK ) return rc;
  pCsr->rowid++;

  if( pTab->eType==FTS5_VOCAB_INSTANCE ){
    return fts5VocabInstanceNext(pCsr);
  }

  if( pTab->eType==FTS5_VOCAB_COL ){
    for(pCsr->iCol++; pCsr->iCol<nCol; pCsr->iCol++){
      if( pCsr->aDoc[pCsr->iCol] ) break;
    }
  }

  if( pTab->eType!=FTS5_VOCAB_COL || pCsr->iCol>=nCol ){
    if( sqlite3Fts5IterEof(pCsr->pIter) ){
      pCsr->bEof = 1;
    }else{
      const char *zTerm;
      int nTerm;

      zTerm = sqlite3Fts5IterTerm(pCsr->pIter, &nTerm);
      assert( nTerm>=0 );
      if( pCsr->nLeTerm>=0 ){
        int nCmp = MIN(nTerm, pCsr->nLeTerm);
        int bCmp = memcmp(pCsr->zLeTerm, zTerm, nCmp);
        if( bCmp<0 || (bCmp==0 && pCsr->nLeTerm<nTerm) ){
          pCsr->bEof = 1;
          return SQLITE_OK;
        }
      }

      sqlite3Fts5BufferSet(&rc, &pCsr->term, nTerm, (const u8*)zTerm);
      memset(pCsr->aCnt, 0, nCol * sizeof(i64));
      memset(pCsr->aDoc, 0, nCol * sizeof(i64));
      pCsr->iCol = 0;

      assert( pTab->eType==FTS5_VOCAB_COL || pTab->eType==FTS5_VOCAB_ROW );
      while( rc==SQLITE_OK ){
        int eDetail = pCsr->pFts5->pConfig->eDetail;
        const u8 *pPos; int nPos;   /* Position list */
        i64 iPos = 0;               /* 64-bit position read from poslist */
        int iOff = 0;               /* Current offset within position list */

        pPos = pCsr->pIter->pData;
        nPos = pCsr->pIter->nData;

        switch( pTab->eType ){
          case FTS5_VOCAB_ROW:
            /* Do not bother counting the number of instances if the "cnt"
            ** column is not being read (according to colUsed).  */
            if( eDetail==FTS5_DETAIL_FULL && (pCsr->colUsed & 0x04) ){
              while( iPos<nPos ){
                u32 ii;
                fts5FastGetVarint32(pPos, iPos, ii);

sqlite3.c  view on Meta::CPAN

                  if( ii>=nCol ){
                    rc = FTS5_CORRUPT;
                    break;
                  }
                  pCsr->aDoc[ii]++;
                  iCol = ii;
                }
                pCsr->aCnt[ii]++;
              }
            }else if( eDetail==FTS5_DETAIL_COLUMNS ){
              while( 0==sqlite3Fts5PoslistNext64(pPos, nPos, &iOff,&iPos) ){
                assert_nc( iPos>=0 && iPos<nCol );
                if( iPos>=nCol ){
                  rc = FTS5_CORRUPT;
                  break;
                }
                pCsr->aDoc[iPos]++;
              }
            }else{
              assert( eDetail==FTS5_DETAIL_NONE );
              pCsr->aDoc[0]++;
            }
            break;

          default:
            assert( pTab->eType==FTS5_VOCAB_INSTANCE );
            break;
        }

        if( rc==SQLITE_OK ){
          rc = sqlite3Fts5IterNextScan(pCsr->pIter);
        }
        if( pTab->eType==FTS5_VOCAB_INSTANCE ) break;

        if( rc==SQLITE_OK ){
          zTerm = sqlite3Fts5IterTerm(pCsr->pIter, &nTerm);
          if( nTerm!=pCsr->term.n
          || (nTerm>0 && memcmp(zTerm, pCsr->term.p, nTerm))
          ){
            break;
          }
          if( sqlite3Fts5IterEof(pCsr->pIter) ) break;
        }
      }
    }
  }

  if( rc==SQLITE_OK && pCsr->bEof==0 && pTab->eType==FTS5_VOCAB_COL ){
    for(/* noop */; pCsr->iCol<nCol && pCsr->aDoc[pCsr->iCol]==0; pCsr->iCol++);
    if( pCsr->iCol==nCol ){
      rc = FTS5_CORRUPT;
    }
  }
  return rc;
}

/*
** This is the xFilter implementation for the virtual table.
*/
static int fts5VocabFilterMethod(
  sqlite3_vtab_cursor *pCursor,   /* The cursor used for this query */
  int idxNum,                     /* Strategy index */
  const char *zUnused,            /* Unused */
  int nUnused,                    /* Number of elements in apVal */
  sqlite3_value **apVal           /* Arguments for the indexing scheme */
){
  Fts5VocabTable *pTab = (Fts5VocabTable*)pCursor->pVtab;
  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
  int eType = pTab->eType;
  int rc = SQLITE_OK;

  int iVal = 0;
  int f = FTS5INDEX_QUERY_SCAN;
  const char *zTerm = 0;
  int nTerm = 0;

  sqlite3_value *pEq = 0;
  sqlite3_value *pGe = 0;
  sqlite3_value *pLe = 0;

  UNUSED_PARAM2(zUnused, nUnused);

  fts5VocabResetCursor(pCsr);
  if( idxNum & FTS5_VOCAB_TERM_EQ ) pEq = apVal[iVal++];
  if( idxNum & FTS5_VOCAB_TERM_GE ) pGe = apVal[iVal++];
  if( idxNum & FTS5_VOCAB_TERM_LE ) pLe = apVal[iVal++];
  pCsr->colUsed = (idxNum & FTS5_VOCAB_COLUSED_MASK);

  if( pEq ){
    zTerm = (const char *)sqlite3_value_text(pEq);
    nTerm = sqlite3_value_bytes(pEq);
    f = FTS5INDEX_QUERY_NOTOKENDATA;
  }else{
    if( pGe ){
      zTerm = (const char *)sqlite3_value_text(pGe);
      nTerm = sqlite3_value_bytes(pGe);
    }
    if( pLe ){
      const char *zCopy = (const char *)sqlite3_value_text(pLe);
      if( zCopy==0 ) zCopy = "";
      pCsr->nLeTerm = sqlite3_value_bytes(pLe);
      pCsr->zLeTerm = sqlite3_malloc(pCsr->nLeTerm+1);
      if( pCsr->zLeTerm==0 ){
        rc = SQLITE_NOMEM;
      }else{
        memcpy(pCsr->zLeTerm, zCopy, pCsr->nLeTerm+1);
      }
    }
  }

  if( rc==SQLITE_OK ){
    Fts5Index *pIndex = pCsr->pFts5->pIndex;
    rc = sqlite3Fts5IndexQuery(pIndex, zTerm, nTerm, f, 0, &pCsr->pIter);
    if( rc==SQLITE_OK ){
      pCsr->pStruct = sqlite3Fts5StructureRef(pIndex);
    }
  }
  if( rc==SQLITE_OK && eType==FTS5_VOCAB_INSTANCE ){
    rc = fts5VocabInstanceNewTerm(pCsr);
  }
  if( rc==SQLITE_OK && !pCsr->bEof
   && (eType!=FTS5_VOCAB_INSTANCE
    || pCsr->pFts5->pConfig->eDetail!=FTS5_DETAIL_NONE)
  ){
    rc = fts5VocabNextMethod(pCursor);
  }

  return rc;
}

/*
** This is the xEof method of the virtual table. SQLite calls this
** routine to find out if it has reached the end of a result set.
*/
static int fts5VocabEofMethod(sqlite3_vtab_cursor *pCursor){
  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
  return pCsr->bEof;
}

static int fts5VocabColumnMethod(
  sqlite3_vtab_cursor *pCursor,   /* Cursor to retrieve value from */
  sqlite3_context *pCtx,          /* Context for sqlite3_result_xxx() calls */
  int iCol                        /* Index of column to read value from */
){
  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
  int eDetail = pCsr->pFts5->pConfig->eDetail;
  int eType = ((Fts5VocabTable*)(pCursor->pVtab))->eType;
  i64 iVal = 0;

  if( iCol==0 ){
    sqlite3_result_text(
        pCtx, (const char*)pCsr->term.p, pCsr->term.n, SQLITE_TRANSIENT
    );
  }else if( eType==FTS5_VOCAB_COL ){
    assert( iCol==1 || iCol==2 || iCol==3 );
    if( iCol==1 ){
      if( eDetail!=FTS5_DETAIL_NONE ){
        const char *z = pCsr->pFts5->pConfig->azCol[pCsr->iCol];
        sqlite3_result_text(pCtx, z, -1, SQLITE_STATIC);
      }
    }else if( iCol==2 ){
      iVal = pCsr->aDoc[pCsr->iCol];
    }else{
      iVal = pCsr->aCnt[pCsr->iCol];
    }
  }else if( eType==FTS5_VOCAB_ROW ){
    assert( iCol==1 || iCol==2 );
    if( iCol==1 ){
      iVal = pCsr->aDoc[0];
    }else{
      iVal = pCsr->aCnt[0];
    }
  }else{
    assert( eType==FTS5_VOCAB_INSTANCE );
    switch( iCol ){
      case 1:
        sqlite3_result_int64(pCtx, pCsr->pIter->iRowid);
        break;
      case 2: {
        int ii = -1;
        if( eDetail==FTS5_DETAIL_FULL ){
          ii = FTS5_POS2COLUMN(pCsr->iInstPos);
        }else if( eDetail==FTS5_DETAIL_COLUMNS ){
          ii = (int)pCsr->iInstPos;
        }
        if( ii>=0 && ii<pCsr->pFts5->pConfig->nCol ){
          const char *z = pCsr->pFts5->pConfig->azCol[ii];
          sqlite3_result_text(pCtx, z, -1, SQLITE_STATIC);
        }
        break;
      }
      default: {
        assert( iCol==3 );
        if( eDetail==FTS5_DETAIL_FULL ){
          int ii = FTS5_POS2OFFSET(pCsr->iInstPos);
          sqlite3_result_int(pCtx, ii);
        }
        break;
      }
    }
  }

  if( iVal>0 ) sqlite3_result_int64(pCtx, iVal);
  return SQLITE_OK;
}

/*
** This is the xRowid method. The SQLite core calls this routine to
** retrieve the rowid for the current row of the result set. The
** rowid should be written to *pRowid.
*/
static int fts5VocabRowidMethod(
  sqlite3_vtab_cursor *pCursor,
  sqlite_int64 *pRowid
){
  Fts5VocabCursor *pCsr = (Fts5VocabCursor*)pCursor;
  *pRowid = pCsr->rowid;
  return SQLITE_OK;
}

static int sqlite3Fts5VocabInit(Fts5Global *pGlobal, sqlite3 *db){
  static const sqlite3_module fts5Vocab = {
    /* iVersion      */ 2,
    /* xCreate       */ fts5VocabCreateMethod,
    /* xConnect      */ fts5VocabConnectMethod,
    /* xBestIndex    */ fts5VocabBestIndexMethod,
    /* xDisconnect   */ fts5VocabDisconnectMethod,
    /* xDestroy      */ fts5VocabDestroyMethod,
    /* xOpen         */ fts5VocabOpenMethod,
    /* xClose        */ fts5VocabCloseMethod,
    /* xFilter       */ fts5VocabFilterMethod,
    /* xNext         */ fts5VocabNextMethod,
    /* xEof          */ fts5VocabEofMethod,
    /* xColumn       */ fts5VocabColumnMethod,
    /* xRowid        */ fts5VocabRowidMethod,
    /* xUpdate       */ 0,
    /* xBegin        */ 0,
    /* xSync         */ 0,
    /* xCommit       */ 0,
    /* xRollback     */ 0,
    /* xFindFunction */ 0,
    /* xRename       */ 0,
    /* xSavepoint    */ 0,
    /* xRelease      */ 0,
    /* xRollbackTo   */ 0,
    /* xShadowName   */ 0,
    /* xIntegrity    */ 0
  };
  void *p = (void*)pGlobal;

  return sqlite3_create_module_v2(db, "fts5vocab", &fts5Vocab, p, 0);
}


/* Here ends the fts5.c composite file. */
#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS5) */

/************** End of fts5.c ************************************************/
/************** Begin file stmt.c ********************************************/
/*
** 2017-05-31
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** This file demonstrates an eponymous virtual table that returns information
** about all prepared statements for the database connection.
**
** Usage example:
**
**     .load ./stmt
**     .mode line
**     .header on
**     SELECT * FROM stmt;
*/
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_STMTVTAB)
#if !defined(SQLITEINT_H)
/* #include "sqlite3ext.h" */
#endif
SQLITE_EXTENSION_INIT1
/* #include <assert.h> */
/* #include <string.h> */

#ifndef SQLITE_OMIT_VIRTUALTABLE


#define STMT_NUM_INTEGER_COLUMN 10
typedef struct StmtRow StmtRow;
struct StmtRow {
  sqlite3_int64 iRowid;                /* Rowid value */
  char *zSql;                          /* column "sql" */
  int aCol[STMT_NUM_INTEGER_COLUMN+1]; /* all other column values */
  StmtRow *pNext;                      /* Next row to return */
};

/* stmt_vtab is a subclass of sqlite3_vtab which will
** serve as the underlying representation of a stmt virtual table
*/
typedef struct stmt_vtab stmt_vtab;
struct stmt_vtab {
  sqlite3_vtab base;  /* Base class - must be first */
  sqlite3 *db;        /* Database connection for this stmt vtab */
};

/* stmt_cursor is a subclass of sqlite3_vtab_cursor which will
** serve as the underlying representation of a cursor that scans
** over rows of the result
*/
typedef struct stmt_cursor stmt_cursor;
struct stmt_cursor {
  sqlite3_vtab_cursor base;  /* Base class - must be first */
  sqlite3 *db;               /* Database connection for this cursor */
  StmtRow *pRow;             /* Current row */
};

/*
** The stmtConnect() method is invoked to create a new
** stmt_vtab that describes the stmt virtual table.
**
** Think of this routine as the constructor for stmt_vtab objects.
**
** All this routine needs to do is:
**
**    (1) Allocate the stmt_vtab object and initialize all fields.
**
**    (2) Tell SQLite (via the sqlite3_declare_vtab() interface) what the
**        result set of queries against stmt will look like.
*/
static int stmtConnect(
  sqlite3 *db,
  void *pAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  stmt_vtab *pNew;
  int rc;

/* Column numbers */
#define STMT_COLUMN_SQL     0   /* SQL for the statement */
#define STMT_COLUMN_NCOL    1   /* Number of result columns */
#define STMT_COLUMN_RO      2   /* True if read-only */
#define STMT_COLUMN_BUSY    3   /* True if currently busy */
#define STMT_COLUMN_NSCAN   4   /* SQLITE_STMTSTATUS_FULLSCAN_STEP */
#define STMT_COLUMN_NSORT   5   /* SQLITE_STMTSTATUS_SORT */
#define STMT_COLUMN_NAIDX   6   /* SQLITE_STMTSTATUS_AUTOINDEX */
#define STMT_COLUMN_NSTEP   7   /* SQLITE_STMTSTATUS_VM_STEP */
#define STMT_COLUMN_REPREP  8   /* SQLITE_STMTSTATUS_REPREPARE */
#define STMT_COLUMN_RUN     9   /* SQLITE_STMTSTATUS_RUN */
#define STMT_COLUMN_MEM    10   /* SQLITE_STMTSTATUS_MEMUSED */


  (void)pAux;
  (void)argc;
  (void)argv;
  (void)pzErr;
  rc = sqlite3_declare_vtab(db,
     "CREATE TABLE x(sql,ncol,ro,busy,nscan,nsort,naidx,nstep,"
                    "reprep,run,mem)");
  if( rc==SQLITE_OK ){
    pNew = sqlite3_malloc64( sizeof(*pNew) );
    *ppVtab = (sqlite3_vtab*)pNew;
    if( pNew==0 ) return SQLITE_NOMEM;
    memset(pNew, 0, sizeof(*pNew));
    pNew->db = db;
  }
  return rc;
}

/*
** This method is the destructor for stmt_cursor objects.
*/
static int stmtDisconnect(sqlite3_vtab *pVtab){
  sqlite3_free(pVtab);
  return SQLITE_OK;
}

/*
** Constructor for a new stmt_cursor object.
*/
static int stmtOpen(sqlite3_vtab *p, sqlite3_vtab_cursor **ppCursor){
  stmt_cursor *pCur;
  pCur = sqlite3_malloc64( sizeof(*pCur) );
  if( pCur==0 ) return SQLITE_NOMEM;
  memset(pCur, 0, sizeof(*pCur));
  pCur->db = ((stmt_vtab*)p)->db;
  *ppCursor = &pCur->base;
  return SQLITE_OK;
}

static void stmtCsrReset(stmt_cursor *pCur){
  StmtRow *pRow = 0;
  StmtRow *pNext = 0;
  for(pRow=pCur->pRow; pRow; pRow=pNext){
    pNext = pRow->pNext;
    sqlite3_free(pRow);
  }
  pCur->pRow = 0;
}

/*
** Destructor for a stmt_cursor.
*/
static int stmtClose(sqlite3_vtab_cursor *cur){
  stmtCsrReset((stmt_cursor*)cur);
  sqlite3_free(cur);
  return SQLITE_OK;
}


/*
** Advance a stmt_cursor to its next row of output.
*/
static int stmtNext(sqlite3_vtab_cursor *cur){
  stmt_cursor *pCur = (stmt_cursor*)cur;
  StmtRow *pNext = pCur->pRow->pNext;
  sqlite3_free(pCur->pRow);
  pCur->pRow = pNext;
  return SQLITE_OK;
}

/*
** Return values of columns for the row at which the stmt_cursor
** is currently pointing.
*/
static int stmtColumn(
  sqlite3_vtab_cursor *cur,   /* The cursor */
  sqlite3_context *ctx,       /* First argument to sqlite3_result_...() */
  int i                       /* Which column to return */
){
  stmt_cursor *pCur = (stmt_cursor*)cur;
  StmtRow *pRow = pCur->pRow;
  if( i==STMT_COLUMN_SQL ){
    sqlite3_result_text(ctx, pRow->zSql, -1, SQLITE_TRANSIENT);
  }else{
    sqlite3_result_int(ctx, pRow->aCol[i]);
  }
  return SQLITE_OK;
}

/*
** Return the rowid for the current row.  In this implementation, the
** rowid is the same as the output value.
*/
static int stmtRowid(sqlite3_vtab_cursor *cur, sqlite_int64 *pRowid){
  stmt_cursor *pCur = (stmt_cursor*)cur;
  *pRowid = pCur->pRow->iRowid;
  return SQLITE_OK;
}

/*
** Return TRUE if the cursor has been moved off of the last
** row of output.
*/
static int stmtEof(sqlite3_vtab_cursor *cur){
  stmt_cursor *pCur = (stmt_cursor*)cur;
  return pCur->pRow==0;
}

/*
** This method is called to "rewind" the stmt_cursor object back
** to the first row of output.  This method is always called at least
** once prior to any call to stmtColumn() or stmtRowid() or
** stmtEof().
*/
static int stmtFilter(
  sqlite3_vtab_cursor *pVtabCursor,
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  stmt_cursor *pCur = (stmt_cursor *)pVtabCursor;
  sqlite3_stmt *p = 0;
  sqlite3_int64 iRowid = 1;
  StmtRow **ppRow = 0;

  (void)idxNum;
  (void)idxStr;
  (void)argc;
  (void)argv;
  stmtCsrReset(pCur);
  ppRow = &pCur->pRow;
  for(p=sqlite3_next_stmt(pCur->db, 0); p; p=sqlite3_next_stmt(pCur->db, p)){
    const char *zSql = sqlite3_sql(p);
    sqlite3_int64 nSql = zSql ? strlen(zSql)+1 : 0;
    StmtRow *pNew = (StmtRow*)sqlite3_malloc64(sizeof(StmtRow) + nSql);

    if( pNew==0 ) return SQLITE_NOMEM;
    memset(pNew, 0, sizeof(StmtRow));
    if( zSql ){
      pNew->zSql = (char*)&pNew[1];
      memcpy(pNew->zSql, zSql, nSql);
    }
    pNew->aCol[STMT_COLUMN_NCOL] = sqlite3_column_count(p);
    pNew->aCol[STMT_COLUMN_RO] = sqlite3_stmt_readonly(p);
    pNew->aCol[STMT_COLUMN_BUSY] = sqlite3_stmt_busy(p);
    pNew->aCol[STMT_COLUMN_NSCAN] = sqlite3_stmt_status(
        p, SQLITE_STMTSTATUS_FULLSCAN_STEP, 0
    );
    pNew->aCol[STMT_COLUMN_NSORT] = sqlite3_stmt_status(
        p, SQLITE_STMTSTATUS_SORT, 0
    );
    pNew->aCol[STMT_COLUMN_NAIDX] = sqlite3_stmt_status(
        p, SQLITE_STMTSTATUS_AUTOINDEX, 0
    );
    pNew->aCol[STMT_COLUMN_NSTEP] = sqlite3_stmt_status(
        p, SQLITE_STMTSTATUS_VM_STEP, 0
    );
    pNew->aCol[STMT_COLUMN_REPREP] = sqlite3_stmt_status(
        p, SQLITE_STMTSTATUS_REPREPARE, 0
    );
    pNew->aCol[STMT_COLUMN_RUN] = sqlite3_stmt_status(
        p, SQLITE_STMTSTATUS_RUN, 0
    );
    pNew->aCol[STMT_COLUMN_MEM] = sqlite3_stmt_status(
        p, SQLITE_STMTSTATUS_MEMUSED, 0
    );
    pNew->iRowid = iRowid++;
    *ppRow = pNew;
    ppRow = &pNew->pNext;
  }

  return SQLITE_OK;
}

/*
** SQLite will invoke this method one or more times while planning a query
** that uses the stmt virtual table.  This routine needs to create
** a query plan for each invocation and compute an estimated cost for that
** plan.
*/
static int stmtBestIndex(
  sqlite3_vtab *tab,
  sqlite3_index_info *pIdxInfo
){
  (void)tab;
  pIdxInfo->estimatedCost = (double)500;
  pIdxInfo->estimatedRows = 500;
  return SQLITE_OK;
}

/*
** This following structure defines all the methods for the
** stmt virtual table.
*/
static sqlite3_module stmtModule = {
  0,                         /* iVersion */
  0,                         /* xCreate */
  stmtConnect,               /* xConnect */
  stmtBestIndex,             /* xBestIndex */
  stmtDisconnect,            /* xDisconnect */
  0,                         /* xDestroy */
  stmtOpen,                  /* xOpen - open a cursor */
  stmtClose,                 /* xClose - close a cursor */
  stmtFilter,                /* xFilter - configure scan constraints */
  stmtNext,                  /* xNext - advance a cursor */
  stmtEof,                   /* xEof - check for end of scan */
  stmtColumn,                /* xColumn - read data */
  stmtRowid,                 /* xRowid - read data */
  0,                         /* xUpdate */
  0,                         /* xBegin */
  0,                         /* xSync */
  0,                         /* xCommit */
  0,                         /* xRollback */
  0,                         /* xFindMethod */
  0,                         /* xRename */
  0,                         /* xSavepoint */
  0,                         /* xRelease */
  0,                         /* xRollbackTo */
  0,                         /* xShadowName */
  0                          /* xIntegrity */
};

#endif /* SQLITE_OMIT_VIRTUALTABLE */

SQLITE_PRIVATE int sqlite3StmtVtabInit(sqlite3 *db){
  int rc = SQLITE_OK;
#ifndef SQLITE_OMIT_VIRTUALTABLE
  rc = sqlite3_create_module(db, "sqlite_stmt", &stmtModule, 0);
#endif
  return rc;
}

#ifndef SQLITE_CORE
#ifdef _WIN32
__declspec(dllexport)
#endif
SQLITE_API int sqlite3_stmt_init(
  sqlite3 *db,
  char **pzErrMsg,
  const sqlite3_api_routines *pApi
){
  int rc = SQLITE_OK;
  SQLITE_EXTENSION_INIT2(pApi);
#ifndef SQLITE_OMIT_VIRTUALTABLE
  rc = sqlite3StmtVtabInit(db);
#endif
  return rc;
}
#endif /* SQLITE_CORE */
#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_STMTVTAB) */

/************** End of stmt.c ************************************************/
/* Return the source-id for this library */
SQLITE_API const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
#endif /* SQLITE_AMALGAMATION */
/************************** End of sqlite3.c ******************************/



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