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ccv-src/lib/3rdparty/sqlite3/sqlite3.c  view on Meta::CPAN

  sqlite3 *pUnlockConnection;           /* Connection to watch for unlock */
  void *pUnlockArg;                     /* Argument to xUnlockNotify */
  void (*xUnlockNotify)(void **, int);  /* Unlock notify callback */
  sqlite3 *pNextBlocked;        /* Next in list of all blocked connections */
#endif
};

/*
** A macro to discover the encoding of a database.
*/
#define ENC(db) ((db)->aDb[0].pSchema->enc)

/*
** Possible values for the sqlite3.flags.
*/
#define SQLITE_VdbeTrace      0x00000001  /* True to trace VDBE execution */
#define SQLITE_InternChanges  0x00000002  /* Uncommitted Hash table changes */
#define SQLITE_FullFSync      0x00000004  /* Use full fsync on the backend */
#define SQLITE_CkptFullFSync  0x00000008  /* Use full fsync for checkpoint */
#define SQLITE_CacheSpill     0x00000010  /* OK to spill pager cache */
#define SQLITE_FullColNames   0x00000020  /* Show full column names on SELECT */
#define SQLITE_ShortColNames  0x00000040  /* Show short columns names */
#define SQLITE_CountRows      0x00000080  /* Count rows changed by INSERT, */
                                          /*   DELETE, or UPDATE and return */
                                          /*   the count using a callback. */
#define SQLITE_NullCallback   0x00000100  /* Invoke the callback once if the */
                                          /*   result set is empty */
#define SQLITE_SqlTrace       0x00000200  /* Debug print SQL as it executes */
#define SQLITE_VdbeListing    0x00000400  /* Debug listings of VDBE programs */
#define SQLITE_WriteSchema    0x00000800  /* OK to update SQLITE_MASTER */
#define SQLITE_VdbeAddopTrace 0x00001000  /* Trace sqlite3VdbeAddOp() calls */
#define SQLITE_IgnoreChecks   0x00002000  /* Do not enforce check constraints */
#define SQLITE_ReadUncommitted 0x0004000  /* For shared-cache mode */
#define SQLITE_LegacyFileFmt  0x00008000  /* Create new databases in format 1 */
#define SQLITE_RecoveryMode   0x00010000  /* Ignore schema errors */
#define SQLITE_ReverseOrder   0x00020000  /* Reverse unordered SELECTs */
#define SQLITE_RecTriggers    0x00040000  /* Enable recursive triggers */
#define SQLITE_ForeignKeys    0x00080000  /* Enforce foreign key constraints  */
#define SQLITE_AutoIndex      0x00100000  /* Enable automatic indexes */
#define SQLITE_PreferBuiltin  0x00200000  /* Preference to built-in funcs */
#define SQLITE_LoadExtension  0x00400000  /* Enable load_extension */
#define SQLITE_EnableTrigger  0x00800000  /* True to enable triggers */
#define SQLITE_DeferFKs       0x01000000  /* Defer all FK constraints */
#define SQLITE_QueryOnly      0x02000000  /* Disable database changes */
#define SQLITE_VdbeEQP        0x04000000  /* Debug EXPLAIN QUERY PLAN */


/*
** Bits of the sqlite3.dbOptFlags field that are used by the
** sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS,...) interface to
** selectively disable various optimizations.
*/
#define SQLITE_QueryFlattener 0x0001   /* Query flattening */
#define SQLITE_ColumnCache    0x0002   /* Column cache */
#define SQLITE_GroupByOrder   0x0004   /* GROUPBY cover of ORDERBY */
#define SQLITE_FactorOutConst 0x0008   /* Constant factoring */
#define SQLITE_IdxRealAsInt   0x0010   /* Store REAL as INT in indices */
#define SQLITE_DistinctOpt    0x0020   /* DISTINCT using indexes */
#define SQLITE_CoverIdxScan   0x0040   /* Covering index scans */
#define SQLITE_OrderByIdxJoin 0x0080   /* ORDER BY of joins via index */
#define SQLITE_SubqCoroutine  0x0100   /* Evaluate subqueries as coroutines */
#define SQLITE_Transitive     0x0200   /* Transitive constraints */
#define SQLITE_OmitNoopJoin   0x0400   /* Omit unused tables in joins */
#define SQLITE_Stat3          0x0800   /* Use the SQLITE_STAT3 table */
#define SQLITE_AdjustOutEst   0x1000   /* Adjust output estimates using WHERE */
#define SQLITE_AllOpts        0xffff   /* All optimizations */

/*
** Macros for testing whether or not optimizations are enabled or disabled.
*/
#ifndef SQLITE_OMIT_BUILTIN_TEST
#define OptimizationDisabled(db, mask)  (((db)->dbOptFlags&(mask))!=0)
#define OptimizationEnabled(db, mask)   (((db)->dbOptFlags&(mask))==0)
#else
#define OptimizationDisabled(db, mask)  0
#define OptimizationEnabled(db, mask)   1
#endif

/*
** Return true if it OK to factor constant expressions into the initialization
** code. The argument is a Parse object for the code generator.
*/
#define ConstFactorOk(P) \
  ((P)->cookieGoto>0 && OptimizationEnabled((P)->db,SQLITE_FactorOutConst))

/*
** Possible values for the sqlite.magic field.
** The numbers are obtained at random and have no special meaning, other
** than being distinct from one another.
*/
#define SQLITE_MAGIC_OPEN     0xa029a697  /* Database is open */
#define SQLITE_MAGIC_CLOSED   0x9f3c2d33  /* Database is closed */
#define SQLITE_MAGIC_SICK     0x4b771290  /* Error and awaiting close */
#define SQLITE_MAGIC_BUSY     0xf03b7906  /* Database currently in use */
#define SQLITE_MAGIC_ERROR    0xb5357930  /* An SQLITE_MISUSE error occurred */
#define SQLITE_MAGIC_ZOMBIE   0x64cffc7f  /* Close with last statement close */

/*
** Each SQL function is defined by an instance of the following
** structure.  A pointer to this structure is stored in the sqlite.aFunc
** hash table.  When multiple functions have the same name, the hash table
** points to a linked list of these structures.
*/
struct FuncDef {
  i16 nArg;            /* Number of arguments.  -1 means unlimited */
  u16 funcFlags;       /* Some combination of SQLITE_FUNC_* */
  void *pUserData;     /* User data parameter */
  FuncDef *pNext;      /* Next function with same name */
  void (*xFunc)(sqlite3_context*,int,sqlite3_value**); /* Regular function */
  void (*xStep)(sqlite3_context*,int,sqlite3_value**); /* Aggregate step */
  void (*xFinalize)(sqlite3_context*);                /* Aggregate finalizer */
  char *zName;         /* SQL name of the function. */
  FuncDef *pHash;      /* Next with a different name but the same hash */
  FuncDestructor *pDestructor;   /* Reference counted destructor function */
};

/*
** This structure encapsulates a user-function destructor callback (as
** configured using create_function_v2()) and a reference counter. When
** create_function_v2() is called to create a function with a destructor,
** a single object of this type is allocated. FuncDestructor.nRef is set to 

ccv-src/lib/3rdparty/sqlite3/sqlite3.c  view on Meta::CPAN

**
** This routine handles all of the register allocation and fills in the
** pDest structure appropriately.
**
** Here is a schematic of the generated code assuming that X is the 
** co-routine entry-point register reg[pDest->iSDParm], that EOF is the
** completed flag reg[pDest->iSDParm+1], and R and S are the range of
** registers that hold the result set, reg[pDest->iSdst] through
** reg[pDest->iSdst+pDest->nSdst-1]:
**
**         X <- A
**         EOF <- 0
**         goto B
**      A: setup for the SELECT
**         loop rows in the SELECT
**           load results into registers R..S
**           yield X
**         end loop
**         cleanup after the SELECT
**         EOF <- 1
**         yield X
**         halt-error
**      B:
**
** To use this subroutine, the caller generates code as follows:
**
**         [ Co-routine generated by this subroutine, shown above ]
**      S: yield X
**         if EOF goto E
**         if skip this row, goto C
**         if terminate loop, goto E
**         deal with this row
**      C: goto S
**      E:
*/
SQLITE_PRIVATE int sqlite3CodeCoroutine(Parse *pParse, Select *pSelect, SelectDest *pDest){
  int regYield;       /* Register holding co-routine entry-point */
  int regEof;         /* Register holding co-routine completion flag */
  int addrTop;        /* Top of the co-routine */
  int j1;             /* Jump instruction */
  int rc;             /* Result code */
  Vdbe *v;            /* VDBE under construction */

  regYield = ++pParse->nMem;
  regEof = ++pParse->nMem;
  v = sqlite3GetVdbe(pParse);
  addrTop = sqlite3VdbeCurrentAddr(v);
  sqlite3VdbeAddOp2(v, OP_Integer, addrTop+2, regYield); /* X <- A */
  VdbeComment((v, "Co-routine entry point"));
  sqlite3VdbeAddOp2(v, OP_Integer, 0, regEof);           /* EOF <- 0 */
  VdbeComment((v, "Co-routine completion flag"));
  sqlite3SelectDestInit(pDest, SRT_Coroutine, regYield);
  j1 = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
  rc = sqlite3Select(pParse, pSelect, pDest);
  assert( pParse->nErr==0 || rc );
  if( pParse->db->mallocFailed && rc==SQLITE_OK ) rc = SQLITE_NOMEM;
  if( rc ) return rc;
  sqlite3VdbeAddOp2(v, OP_Integer, 1, regEof);            /* EOF <- 1 */
  sqlite3VdbeAddOp1(v, OP_Yield, regYield);   /* yield X */
  sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
  VdbeComment((v, "End of coroutine"));
  sqlite3VdbeJumpHere(v, j1);                             /* label B: */
  return rc;
}



/* 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)
**    insert into TABLE (IDLIST) select
**
** The IDLIST following the table name is always optional.  If omitted,
** then a list of all columns for the table is substituted.  The IDLIST
** appears in the pColumn parameter.  pColumn is NULL if IDLIST is omitted.
**
** The pList parameter holds EXPRLIST in the first form of the INSERT
** statement above, and pSelect is NULL.  For the second form, pList is
** NULL and pSelect is a pointer to the select statement used to generate
** data for the insert.
**
** The code generated follows one of four templates.  For a simple
** insert with data coming from a 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

ccv-src/lib/3rdparty/sqlite3/sqlite3.c  view on Meta::CPAN

**         if 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 a intermediate table to store the results of
** the select.  The template is like this:
**
**         EOF <- 0
**         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
**         EOF <- 1
**         yield X
**         halt-error
**      B: open temp table
**      L: yield X
**         if 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 */
  ExprList *pList,      /* List of values to be inserted */
  Select *pSelect,      /* A SELECT statement to use as the data source */
  IdList *pColumn,      /* Column names corresponding to IDLIST. */
  int onError           /* How to handle constraint errors */
){
  sqlite3 *db;          /* The main database structure */
  Table *pTab;          /* The table to insert into.  aka TABLE */
  char *zTab;           /* Name of the table into which we are inserting */
  const char *zDb;      /* Name of the database holding this table */
  int i, j, idx;        /* 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 useTempTable = 0; /* Store SELECT results in intermediate table */
  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 */
  int addrSelect = 0;   /* Address of coroutine that implements the SELECT */
  SelectDest dest;      /* Destination for SELECT on rhs of INSERT */
  int iDb;              /* Index of database holding TABLE */
  Db *pDb;              /* The database containing table being inserted into */
  int appendFlag = 0;   /* True if the insert is likely to be an append */
  int withoutRowid;     /* 0 for normal table.  1 for WITHOUT ROWID table */

  /* 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 regEof = 0;       /* Register recording end of SELECT data */
  int *aRegIdx = 0;     /* One register allocated to each index */

#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;
  memset(&dest, 0, sizeof(dest));
  if( pParse->nErr || db->mallocFailed ){
    goto insert_cleanup;
  }

  /* Locate the table into which we will be inserting new information.
  */
  assert( pTabList->nSrc==1 );
  zTab = pTabList->a[0].zName;
  if( NEVER(zTab==0) ) goto insert_cleanup;
  pTab = sqlite3SrcListLookup(pParse, pTabList);
  if( pTab==0 ){
    goto insert_cleanup;
  }
  iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
  assert( iDb<db->nDb );
  pDb = &db->aDb[iDb];
  zDb = pDb->zName;
  if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0, zDb) ){
    goto insert_cleanup;
  }
  withoutRowid = !HasRowid(pTab);

  /* Figure out if we have any triggers and if the table being
  ** inserted into is a view
  */
#ifndef SQLITE_OMIT_TRIGGER
  pTrigger = sqlite3TriggersExist(pParse, pTab, TK_INSERT, 0, &tmask);
  isView = pTab->pSelect!=0;
#else
# define pTrigger 0
# define tmask 0
# define isView 0
#endif
#ifdef SQLITE_OMIT_VIEW
# undef isView
# define isView 0

ccv-src/lib/3rdparty/sqlite3/sqlite3.c  view on Meta::CPAN


  /* Allocate a VDBE
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto insert_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, pSelect || pTrigger, iDb);

#ifndef SQLITE_OMIT_XFER_OPT
  /* If the statement is of the form
  **
  **       INSERT INTO <table1> SELECT * FROM <table2>;
  **
  ** Then special optimizations can be applied that make the transfer
  ** very fast and which reduce fragmentation of indices.
  **
  ** This is the 2nd template.
  */
  if( pColumn==0 && xferOptimization(pParse, pTab, pSelect, onError, iDb) ){
    assert( !pTrigger );
    assert( pList==0 );
    goto insert_end;
  }
#endif /* SQLITE_OMIT_XFER_OPT */

  /* If this is an AUTOINCREMENT table, look up the sequence number in the
  ** sqlite_sequence table and store it in memory cell regAutoinc.
  */
  regAutoinc = autoIncBegin(pParse, iDb, pTab);

  /* Figure out how many columns of data are supplied.  If the data
  ** is coming from a SELECT statement, then generate a co-routine that
  ** produces a single row of the SELECT on each invocation.  The
  ** co-routine is the common header to the 3rd and 4th templates.
  */
  if( pSelect ){
    /* Data is coming from a SELECT.  Generate a co-routine to run the SELECT */
    int rc = sqlite3CodeCoroutine(pParse, pSelect, &dest);
    if( rc ) goto insert_cleanup;

    regEof = dest.iSDParm + 1;
    regFromSelect = dest.iSdst;
    assert( pSelect->pEList );
    nColumn = pSelect->pEList->nExpr;
    assert( dest.nSdst==nColumn );

    /* Set useTempTable to TRUE if the result of the SELECT statement
    ** should be written into a temporary table (template 4).  Set to
    ** FALSE if each output row of the SELECT can be written directly into
    ** the destination table (template 3).
    **
    ** A temp table must be used if the table being updated is also one
    ** of the tables being read by the SELECT statement.  Also use a 
    ** temp table in the case of row triggers.
    */
    if( pTrigger || readsTable(pParse, addrSelect, iDb, pTab) ){
      useTempTable = 1;
    }

    if( useTempTable ){
      /* Invoke the coroutine to extract information from the SELECT
      ** and add it to a transient table srcTab.  The code generated
      ** here is from the 4th template:
      **
      **      B: open temp table
      **      L: yield X
      **         if EOF goto M
      **         insert row from R..R+n into temp table
      **         goto L
      **      M: ...
      */
      int regRec;          /* Register to hold packed record */
      int regTempRowid;    /* Register to hold temp table ROWID */
      int addrTop;         /* Label "L" */
      int addrIf;          /* Address of jump to M */

      srcTab = pParse->nTab++;
      regRec = sqlite3GetTempReg(pParse);
      regTempRowid = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
      addrTop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
      addrIf = sqlite3VdbeAddOp1(v, OP_If, regEof);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
      sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
      sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
      sqlite3VdbeJumpHere(v, addrIf);
      sqlite3ReleaseTempReg(pParse, regRec);
      sqlite3ReleaseTempReg(pParse, regTempRowid);
    }
  }else{
    /* This is the case if the data for the INSERT is coming from a VALUES
    ** clause
    */
    NameContext sNC;
    memset(&sNC, 0, sizeof(sNC));
    sNC.pParse = pParse;
    srcTab = -1;
    assert( useTempTable==0 );
    nColumn = pList ? pList->nExpr : 0;
    for(i=0; i<nColumn; i++){
      if( sqlite3ResolveExprNames(&sNC, pList->a[i].pExpr) ){
        goto insert_cleanup;
      }
    }
  }

  /* Make sure the number of columns in the source data matches the number
  ** of columns to be inserted into the table.
  */
  if( IsVirtual(pTab) ){
    for(i=0; i<pTab->nCol; i++){
      nHidden += (IsHiddenColumn(&pTab->aCol[i]) ? 1 : 0);
    }
  }
  if( pColumn==0 && nColumn && nColumn!=(pTab->nCol-nHidden) ){
    sqlite3ErrorMsg(pParse, 
       "table %S has %d columns but %d values were supplied",
       pTabList, 0, pTab->nCol-nHidden, nColumn);
    goto insert_cleanup;
  }

ccv-src/lib/3rdparty/sqlite3/sqlite3.c  view on Meta::CPAN


  explainComposite(pParse, p->op, iSub1, iSub2, p->op!=TK_ALL);

  /* Compute collating sequences used by 
  ** temporary tables needed to implement the compound select.
  ** Attach the KeyInfo structure to all temporary tables.
  **
  ** This section is run by the right-most SELECT statement only.
  ** SELECT statements to the left always skip this part.  The right-most
  ** SELECT might also skip this part if it has no ORDER BY clause and
  ** no temp tables are required.
  */
  if( p->selFlags & SF_UsesEphemeral ){
    int i;                        /* Loop counter */
    KeyInfo *pKeyInfo;            /* Collating sequence for the result set */
    Select *pLoop;                /* For looping through SELECT statements */
    CollSeq **apColl;             /* For looping through pKeyInfo->aColl[] */
    int nCol;                     /* Number of columns in result set */

    assert( p->pRightmost==p );
    nCol = p->pEList->nExpr;
    pKeyInfo = sqlite3KeyInfoAlloc(db, nCol, 1);
    if( !pKeyInfo ){
      rc = SQLITE_NOMEM;
      goto multi_select_end;
    }
    for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
      *apColl = multiSelectCollSeq(pParse, p, i);
      if( 0==*apColl ){
        *apColl = db->pDfltColl;
      }
    }

    for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
      for(i=0; i<2; i++){
        int addr = pLoop->addrOpenEphm[i];
        if( addr<0 ){
          /* If [0] is unused then [1] is also unused.  So we can
          ** always safely abort as soon as the first unused slot is found */
          assert( pLoop->addrOpenEphm[1]<0 );
          break;
        }
        sqlite3VdbeChangeP2(v, addr, nCol);
        sqlite3VdbeChangeP4(v, addr, (char*)sqlite3KeyInfoRef(pKeyInfo),
                            P4_KEYINFO);
        pLoop->addrOpenEphm[i] = -1;
      }
    }
    sqlite3KeyInfoUnref(pKeyInfo);
  }

multi_select_end:
  pDest->iSdst = dest.iSdst;
  pDest->nSdst = dest.nSdst;
  sqlite3SelectDelete(db, pDelete);
  return rc;
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */

/*
** Code an output subroutine for a coroutine implementation of a
** SELECT statment.
**
** The data to be output is contained in pIn->iSdst.  There are
** pIn->nSdst columns to be output.  pDest is where the output should
** be sent.
**
** regReturn is the number of the register holding the subroutine
** return address.
**
** If regPrev>0 then it is the first register in a vector that
** records the previous output.  mem[regPrev] is a flag that is false
** if there has been no previous output.  If regPrev>0 then code is
** generated to suppress duplicates.  pKeyInfo is used for comparing
** keys.
**
** If the LIMIT found in p->iLimit is reached, jump immediately to
** iBreak.
*/
static int generateOutputSubroutine(
  Parse *pParse,          /* Parsing context */
  Select *p,              /* The SELECT statement */
  SelectDest *pIn,        /* Coroutine supplying data */
  SelectDest *pDest,      /* Where to send the data */
  int regReturn,          /* The return address register */
  int regPrev,            /* Previous result register.  No uniqueness if 0 */
  KeyInfo *pKeyInfo,      /* For comparing with previous entry */
  int iBreak              /* Jump here if we hit the LIMIT */
){
  Vdbe *v = pParse->pVdbe;
  int iContinue;
  int addr;

  addr = sqlite3VdbeCurrentAddr(v);
  iContinue = sqlite3VdbeMakeLabel(v);

  /* Suppress duplicates for UNION, EXCEPT, and INTERSECT 
  */
  if( regPrev ){
    int j1, j2;
    j1 = sqlite3VdbeAddOp1(v, OP_IfNot, regPrev);
    j2 = sqlite3VdbeAddOp4(v, OP_Compare, pIn->iSdst, regPrev+1, pIn->nSdst,
                              (char*)sqlite3KeyInfoRef(pKeyInfo), P4_KEYINFO);
    sqlite3VdbeAddOp3(v, OP_Jump, j2+2, iContinue, j2+2);
    sqlite3VdbeJumpHere(v, j1);
    sqlite3VdbeAddOp3(v, OP_Copy, pIn->iSdst, regPrev+1, pIn->nSdst-1);
    sqlite3VdbeAddOp2(v, OP_Integer, 1, regPrev);
  }
  if( pParse->db->mallocFailed ) return 0;

  /* Suppress the first OFFSET entries if there is an OFFSET clause
  */
  codeOffset(v, p, iContinue);

  switch( pDest->eDest ){
    /* Store the result as data using a unique key.
    */
    case SRT_Table:
    case SRT_EphemTab: {
      int r1 = sqlite3GetTempReg(pParse);
      int r2 = sqlite3GetTempReg(pParse);

ccv-src/lib/3rdparty/sqlite3/sqlite3.c  view on Meta::CPAN

      sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSDParm, 1);
      /* The LIMIT clause will jump out of the loop for us */
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */

    /* The results are stored in a sequence of registers
    ** starting at pDest->iSdst.  Then the co-routine yields.
    */
    case SRT_Coroutine: {
      if( pDest->iSdst==0 ){
        pDest->iSdst = sqlite3GetTempRange(pParse, pIn->nSdst);
        pDest->nSdst = pIn->nSdst;
      }
      sqlite3ExprCodeMove(pParse, pIn->iSdst, pDest->iSdst, pDest->nSdst);
      sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
      break;
    }

    /* If none of the above, then the result destination must be
    ** SRT_Output.  This routine is never called with any other
    ** destination other than the ones handled above or SRT_Output.
    **
    ** For SRT_Output, results are stored in a sequence of registers.  
    ** Then the OP_ResultRow opcode is used to cause sqlite3_step() to
    ** return the next row of result.
    */
    default: {
      assert( pDest->eDest==SRT_Output );
      sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iSdst, pIn->nSdst);
      sqlite3ExprCacheAffinityChange(pParse, pIn->iSdst, pIn->nSdst);
      break;
    }
  }

  /* Jump to the end of the loop if the LIMIT is reached.
  */
  if( p->iLimit ){
    sqlite3VdbeAddOp3(v, OP_IfZero, p->iLimit, iBreak, -1);
  }

  /* Generate the subroutine return
  */
  sqlite3VdbeResolveLabel(v, iContinue);
  sqlite3VdbeAddOp1(v, OP_Return, regReturn);

  return addr;
}

/*
** Alternative compound select code generator for cases when there
** is an ORDER BY clause.
**
** We assume a query of the following form:
**
**      <selectA>  <operator>  <selectB>  ORDER BY <orderbylist>
**
** <operator> is one of UNION ALL, UNION, EXCEPT, or INTERSECT.  The idea
** is to code both <selectA> and <selectB> with the ORDER BY clause as
** co-routines.  Then run the co-routines in parallel and merge the results
** into the output.  In addition to the two coroutines (called selectA and
** selectB) there are 7 subroutines:
**
**    outA:    Move the output of the selectA coroutine into the output
**             of the compound query.
**
**    outB:    Move the output of the selectB coroutine into the output
**             of the compound query.  (Only generated for UNION and
**             UNION ALL.  EXCEPT and INSERTSECT never output a row that
**             appears only in B.)
**
**    AltB:    Called when there is data from both coroutines and A<B.
**
**    AeqB:    Called when there is data from both coroutines and A==B.
**
**    AgtB:    Called when there is data from both coroutines and A>B.
**
**    EofA:    Called when data is exhausted from selectA.
**
**    EofB:    Called when data is exhausted from selectB.
**
** The implementation of the latter five subroutines depend on which 
** <operator> is used:
**
**
**             UNION ALL         UNION            EXCEPT          INTERSECT
**          -------------  -----------------  --------------  -----------------
**   AltB:   outA, nextA      outA, nextA       outA, nextA         nextA
**
**   AeqB:   outA, nextA         nextA             nextA         outA, nextA
**
**   AgtB:   outB, nextB      outB, nextB          nextB            nextB
**
**   EofA:   outB, nextB      outB, nextB          halt             halt
**
**   EofB:   outA, nextA      outA, nextA       outA, nextA         halt
**
** In the AltB, AeqB, and AgtB subroutines, an EOF on A following nextA
** causes an immediate jump to EofA and an EOF on B following nextB causes
** an immediate jump to EofB.  Within EofA and EofB, and EOF on entry or
** following nextX causes a jump to the end of the select processing.
**
** Duplicate removal in the UNION, EXCEPT, and INTERSECT cases is handled
** within the output subroutine.  The regPrev register set holds the previously
** output value.  A comparison is made against this value and the output
** is skipped if the next results would be the same as the previous.
**
** The implementation plan is to implement the two coroutines and seven
** subroutines first, then put the control logic at the bottom.  Like this:
**
**          goto Init
**     coA: coroutine for left query (A)
**     coB: coroutine for right query (B)
**    outA: output one row of A
**    outB: output one row of B (UNION and UNION ALL only)
**    EofA: ...
**    EofB: ...
**    AltB: ...
**    AeqB: ...
**    AgtB: ...
**    Init: initialize coroutine registers
**          yield coA
**          if eof(A) goto EofA
**          yield coB
**          if eof(B) goto EofB
**    Cmpr: Compare A, B
**          Jump AltB, AeqB, AgtB
**     End: ...
**
** We call AltB, AeqB, AgtB, EofA, and EofB "subroutines" but they are not
** actually called using Gosub and they do not Return.  EofA and EofB loop
** until all data is exhausted then jump to the "end" labe.  AltB, AeqB,
** and AgtB jump to either L2 or to one of EofA or EofB.
*/
#ifndef SQLITE_OMIT_COMPOUND_SELECT
static int multiSelectOrderBy(
  Parse *pParse,        /* Parsing context */
  Select *p,            /* The right-most of SELECTs to be coded */
  SelectDest *pDest     /* What to do with query results */
){
  int i, j;             /* Loop counters */
  Select *pPrior;       /* Another SELECT immediately to our left */
  Vdbe *v;              /* Generate code to this VDBE */
  SelectDest destA;     /* Destination for coroutine A */
  SelectDest destB;     /* Destination for coroutine B */
  int regAddrA;         /* Address register for select-A coroutine */
  int regEofA;          /* Flag to indicate when select-A is complete */
  int regAddrB;         /* Address register for select-B coroutine */
  int regEofB;          /* Flag to indicate when select-B is complete */
  int addrSelectA;      /* Address of the select-A coroutine */
  int addrSelectB;      /* Address of the select-B coroutine */
  int regOutA;          /* Address register for the output-A subroutine */
  int regOutB;          /* Address register for the output-B subroutine */
  int addrOutA;         /* Address of the output-A subroutine */
  int addrOutB = 0;     /* Address of the output-B subroutine */
  int addrEofA;         /* Address of the select-A-exhausted subroutine */
  int addrEofB;         /* Address of the select-B-exhausted subroutine */
  int addrAltB;         /* Address of the A<B subroutine */
  int addrAeqB;         /* Address of the A==B subroutine */
  int addrAgtB;         /* Address of the A>B subroutine */
  int regLimitA;        /* Limit register for select-A */
  int regLimitB;        /* Limit register for select-A */
  int regPrev;          /* A range of registers to hold previous output */
  int savedLimit;       /* Saved value of p->iLimit */
  int savedOffset;      /* Saved value of p->iOffset */
  int labelCmpr;        /* Label for the start of the merge algorithm */
  int labelEnd;         /* Label for the end of the overall SELECT stmt */
  int j1;               /* Jump instructions that get retargetted */
  int op;               /* One of TK_ALL, TK_UNION, TK_EXCEPT, TK_INTERSECT */
  KeyInfo *pKeyDup = 0; /* Comparison information for duplicate removal */
  KeyInfo *pKeyMerge;   /* Comparison information for merging rows */
  sqlite3 *db;          /* Database connection */
  ExprList *pOrderBy;   /* The ORDER BY clause */
  int nOrderBy;         /* Number of terms in the ORDER BY clause */
  int *aPermute;        /* Mapping from ORDER BY terms to result set columns */
#ifndef SQLITE_OMIT_EXPLAIN
  int iSub1;            /* EQP id of left-hand query */
  int iSub2;            /* EQP id of right-hand query */
#endif

  assert( p->pOrderBy!=0 );
  assert( pKeyDup==0 ); /* "Managed" code needs this.  Ticket #3382. */
  db = pParse->db;
  v = pParse->pVdbe;
  assert( v!=0 );       /* Already thrown the error if VDBE alloc failed */
  labelEnd = sqlite3VdbeMakeLabel(v);
  labelCmpr = sqlite3VdbeMakeLabel(v);


  /* Patch up the ORDER BY clause
  */
  op = p->op;  
  pPrior = p->pPrior;
  assert( pPrior->pOrderBy==0 );
  pOrderBy = p->pOrderBy;
  assert( pOrderBy );
  nOrderBy = pOrderBy->nExpr;

  /* For operators other than UNION ALL we have to make sure that
  ** the ORDER BY clause covers every term of the result set.  Add
  ** terms to the ORDER BY clause as necessary.
  */
  if( op!=TK_ALL ){
    for(i=1; db->mallocFailed==0 && i<=p->pEList->nExpr; i++){
      struct ExprList_item *pItem;
      for(j=0, pItem=pOrderBy->a; j<nOrderBy; j++, pItem++){
        assert( pItem->u.x.iOrderByCol>0 );
        if( pItem->u.x.iOrderByCol==i ) break;
      }
      if( j==nOrderBy ){
        Expr *pNew = sqlite3Expr(db, TK_INTEGER, 0);

ccv-src/lib/3rdparty/sqlite3/sqlite3.c  view on Meta::CPAN

  /* Reattach the ORDER BY clause to the query.
  */
  p->pOrderBy = pOrderBy;
  pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, pOrderBy, 0);

  /* Allocate a range of temporary registers and the KeyInfo needed
  ** for the logic that removes duplicate result rows when the
  ** operator is UNION, EXCEPT, or INTERSECT (but not UNION ALL).
  */
  if( op==TK_ALL ){
    regPrev = 0;
  }else{
    int nExpr = p->pEList->nExpr;
    assert( nOrderBy>=nExpr || db->mallocFailed );
    regPrev = pParse->nMem+1;
    pParse->nMem += nExpr+1;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regPrev);
    pKeyDup = sqlite3KeyInfoAlloc(db, nExpr, 1);
    if( pKeyDup ){
      assert( sqlite3KeyInfoIsWriteable(pKeyDup) );
      for(i=0; i<nExpr; i++){
        pKeyDup->aColl[i] = multiSelectCollSeq(pParse, p, i);
        pKeyDup->aSortOrder[i] = 0;
      }
    }
  }
 
  /* Separate the left and the right query from one another
  */
  p->pPrior = 0;
  sqlite3ResolveOrderGroupBy(pParse, p, p->pOrderBy, "ORDER");
  if( pPrior->pPrior==0 ){
    sqlite3ResolveOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, "ORDER");
  }

  /* Compute the limit registers */
  computeLimitRegisters(pParse, p, labelEnd);
  if( p->iLimit && op==TK_ALL ){
    regLimitA = ++pParse->nMem;
    regLimitB = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Copy, p->iOffset ? p->iOffset+1 : p->iLimit,
                                  regLimitA);
    sqlite3VdbeAddOp2(v, OP_Copy, regLimitA, regLimitB);
  }else{
    regLimitA = regLimitB = 0;
  }
  sqlite3ExprDelete(db, p->pLimit);
  p->pLimit = 0;
  sqlite3ExprDelete(db, p->pOffset);
  p->pOffset = 0;

  regAddrA = ++pParse->nMem;
  regEofA = ++pParse->nMem;
  regAddrB = ++pParse->nMem;
  regEofB = ++pParse->nMem;
  regOutA = ++pParse->nMem;
  regOutB = ++pParse->nMem;
  sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
  sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);

  /* Jump past the various subroutines and coroutines to the main
  ** merge loop
  */
  j1 = sqlite3VdbeAddOp0(v, OP_Goto);
  addrSelectA = sqlite3VdbeCurrentAddr(v);


  /* Generate a coroutine to evaluate the SELECT statement to the
  ** left of the compound operator - the "A" select.
  */
  VdbeNoopComment((v, "Begin coroutine for left SELECT"));
  pPrior->iLimit = regLimitA;
  explainSetInteger(iSub1, pParse->iNextSelectId);
  sqlite3Select(pParse, pPrior, &destA);
  sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
  VdbeNoopComment((v, "End coroutine for left SELECT"));

  /* Generate a coroutine to evaluate the SELECT statement on 
  ** the right - the "B" select
  */
  addrSelectB = sqlite3VdbeCurrentAddr(v);
  VdbeNoopComment((v, "Begin coroutine for right SELECT"));
  savedLimit = p->iLimit;
  savedOffset = p->iOffset;
  p->iLimit = regLimitB;
  p->iOffset = 0;  
  explainSetInteger(iSub2, pParse->iNextSelectId);
  sqlite3Select(pParse, p, &destB);
  p->iLimit = savedLimit;
  p->iOffset = savedOffset;
  sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofB);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
  VdbeNoopComment((v, "End coroutine for right SELECT"));

  /* Generate a subroutine that outputs the current row of the A
  ** select as the next output row of the compound select.
  */
  VdbeNoopComment((v, "Output routine for A"));
  addrOutA = generateOutputSubroutine(pParse,
                 p, &destA, pDest, regOutA,
                 regPrev, pKeyDup, labelEnd);
  
  /* Generate a subroutine that outputs the current row of the B
  ** select as the next output row of the compound select.
  */
  if( op==TK_ALL || op==TK_UNION ){
    VdbeNoopComment((v, "Output routine for B"));
    addrOutB = generateOutputSubroutine(pParse,
                 p, &destB, pDest, regOutB,
                 regPrev, pKeyDup, labelEnd);
  }
  sqlite3KeyInfoUnref(pKeyDup);

  /* Generate a subroutine to run when the results from select A
  ** are exhausted and only data in select B remains.
  */
  VdbeNoopComment((v, "eof-A subroutine"));
  if( op==TK_EXCEPT || op==TK_INTERSECT ){
    addrEofA = sqlite3VdbeAddOp2(v, OP_Goto, 0, labelEnd);
  }else{  
    addrEofA = sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
    sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
    sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofA);
    p->nSelectRow += pPrior->nSelectRow;
  }

  /* Generate a subroutine to run when the results from select B
  ** are exhausted and only data in select A remains.
  */
  if( op==TK_INTERSECT ){
    addrEofB = addrEofA;
    if( p->nSelectRow > pPrior->nSelectRow ) p->nSelectRow = pPrior->nSelectRow;
  }else{  
    VdbeNoopComment((v, "eof-B subroutine"));
    addrEofB = sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
    sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
    sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, addrEofB);
  }

  /* Generate code to handle the case of A<B
  */
  VdbeNoopComment((v, "A-lt-B subroutine"));
  addrAltB = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
  sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
  sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);

  /* Generate code to handle the case of A==B
  */
  if( op==TK_ALL ){
    addrAeqB = addrAltB;

ccv-src/lib/3rdparty/sqlite3/sqlite3.c  view on Meta::CPAN

  for(i=0; !p->pPrior && i<pTabList->nSrc; i++){
    struct SrcList_item *pItem = &pTabList->a[i];
    SelectDest dest;
    Select *pSub = pItem->pSelect;
    int isAggSub;

    if( pSub==0 ) continue;

    /* Sometimes the code for a subquery will be generated more than
    ** once, if the subquery is part of the WHERE clause in a LEFT JOIN,
    ** for example.  In that case, do not regenerate the code to manifest
    ** a view or the co-routine to implement a view.  The first instance
    ** is sufficient, though the subroutine to manifest the view does need
    ** to be invoked again. */
    if( pItem->addrFillSub ){
      if( pItem->viaCoroutine==0 ){
        sqlite3VdbeAddOp2(v, OP_Gosub, pItem->regReturn, pItem->addrFillSub);
      }
      continue;
    }

    /* Increment Parse.nHeight by the height of the largest expression
    ** tree referred to by this, the parent select. The child select
    ** may contain expression trees of at most
    ** (SQLITE_MAX_EXPR_DEPTH-Parse.nHeight) height. This is a bit
    ** more conservative than necessary, but much easier than enforcing
    ** an exact limit.
    */
    pParse->nHeight += sqlite3SelectExprHeight(p);

    isAggSub = (pSub->selFlags & SF_Aggregate)!=0;
    if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){
      /* This subquery can be absorbed into its parent. */
      if( isAggSub ){
        isAgg = 1;
        p->selFlags |= SF_Aggregate;
      }
      i = -1;
    }else if( pTabList->nSrc==1 && (p->selFlags & SF_Materialize)==0
      && OptimizationEnabled(db, SQLITE_SubqCoroutine)
    ){
      /* Implement a co-routine that will return a single row of the result
      ** set on each invocation.
      */
      int addrTop;
      int addrEof;
      pItem->regReturn = ++pParse->nMem;
      addrEof = ++pParse->nMem;
      /* Before coding the OP_Goto to jump to the start of the main routine,
      ** ensure that the jump to the verify-schema routine has already
      ** been coded. Otherwise, the verify-schema would likely be coded as 
      ** part of the co-routine. If the main routine then accessed the 
      ** database before invoking the co-routine for the first time (for 
      ** example to initialize a LIMIT register from a sub-select), it would 
      ** be doing so without having verified the schema version and obtained 
      ** the required db locks. See ticket d6b36be38.  */
      sqlite3CodeVerifySchema(pParse, -1);
      sqlite3VdbeAddOp0(v, OP_Goto);
      addrTop = sqlite3VdbeAddOp1(v, OP_OpenPseudo, pItem->iCursor);
      sqlite3VdbeChangeP5(v, 1);
      VdbeComment((v, "coroutine for %s", pItem->pTab->zName));
      pItem->addrFillSub = addrTop;
      sqlite3VdbeAddOp2(v, OP_Integer, 0, addrEof);
      sqlite3VdbeChangeP5(v, 1);
      sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->regReturn);
      explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
      sqlite3Select(pParse, pSub, &dest);
      pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;
      pItem->viaCoroutine = 1;
      sqlite3VdbeChangeP2(v, addrTop, dest.iSdst);
      sqlite3VdbeChangeP3(v, addrTop, dest.nSdst);
      sqlite3VdbeAddOp2(v, OP_Integer, 1, addrEof);
      sqlite3VdbeAddOp1(v, OP_Yield, pItem->regReturn);
      VdbeComment((v, "end %s", pItem->pTab->zName));
      sqlite3VdbeJumpHere(v, addrTop-1);
      sqlite3ClearTempRegCache(pParse);
    }else{
      /* Generate a subroutine that will fill an ephemeral table with
      ** the content of this subquery.  pItem->addrFillSub will point
      ** to the address of the generated subroutine.  pItem->regReturn
      ** is a register allocated to hold the subroutine return address
      */
      int topAddr;
      int onceAddr = 0;
      int retAddr;
      assert( pItem->addrFillSub==0 );
      pItem->regReturn = ++pParse->nMem;
      topAddr = sqlite3VdbeAddOp2(v, OP_Integer, 0, pItem->regReturn);
      pItem->addrFillSub = topAddr+1;
      VdbeNoopComment((v, "materialize %s", pItem->pTab->zName));
      if( pItem->isCorrelated==0 ){
        /* If the subquery is not correlated and if we are not inside of
        ** a trigger, then we only need to compute the value of the subquery
        ** once. */
        onceAddr = sqlite3CodeOnce(pParse);
      }
      sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
      explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId);
      sqlite3Select(pParse, pSub, &dest);
      pItem->pTab->nRowEst = (unsigned)pSub->nSelectRow;
      if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr);
      retAddr = sqlite3VdbeAddOp1(v, OP_Return, pItem->regReturn);
      VdbeComment((v, "end %s", pItem->pTab->zName));
      sqlite3VdbeChangeP1(v, topAddr, retAddr);
      sqlite3ClearTempRegCache(pParse);
    }
    if( /*pParse->nErr ||*/ db->mallocFailed ){
      goto select_end;
    }
    pParse->nHeight -= sqlite3SelectExprHeight(p);
    pTabList = p->pSrc;
    if( !IgnorableOrderby(pDest) ){
      pOrderBy = p->pOrderBy;
    }
  }
  pEList = p->pEList;
#endif
  pWhere = p->pWhere;
  pGroupBy = p->pGroupBy;
  pHaving = p->pHaving;
  sDistinct.isTnct = (p->selFlags & SF_Distinct)!=0;



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