DBD-SQLite-Amalgamation
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sqlite-amalgamation.c view on Meta::CPAN
** file header points to the first in a linked list of trunk page. Each trunk
** page points to multiple leaf pages. The content of a leaf page is
** unspecified. A trunk page looks like this:
**
** SIZE DESCRIPTION
** 4 Page number of next trunk page
** 4 Number of leaf pointers on this page
** * zero or more pages numbers of leaves
*/
/* Round up a number to the next larger multiple of 8. This is used
** to force 8-byte alignment on 64-bit architectures.
*/
#define ROUND8(x) ((x+7)&~7)
/* The following value is the maximum cell size assuming a maximum page
** size give above.
*/
#define MX_CELL_SIZE(pBt) (pBt->pageSize-8)
/* The maximum number of cells on a single page of the database. This
** assumes a minimum cell size of 6 bytes (4 bytes for the cell itself
** plus 2 bytes for the index to the cell in the page header). Such
** small cells will be rare, but they are possible.
*/
#define MX_CELL(pBt) ((pBt->pageSize-8)/6)
/* Forward declarations */
typedef struct MemPage MemPage;
typedef struct BtLock BtLock;
/*
** This is a magic string that appears at the beginning of every
** SQLite database in order to identify the file as a real database.
**
** You can change this value at compile-time by specifying a
** -DSQLITE_FILE_HEADER="..." on the compiler command-line. The
** header must be exactly 16 bytes including the zero-terminator so
** the string itself should be 15 characters long. If you change
** the header, then your custom library will not be able to read
** databases generated by the standard tools and the standard tools
** will not be able to read databases created by your custom library.
*/
#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
/*
** As each page of the file is loaded into memory, an instance of the following
** structure is appended and initialized to zero. This structure stores
** information about the page that is decoded from the raw file page.
**
** The pParent field points back to the parent page. This allows us to
** walk up the BTree from any leaf to the root. Care must be taken to
** unref() the parent page pointer when this page is no longer referenced.
** The pageDestructor() routine handles that chore.
**
** 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 idxShift; /* True if Cell indices have changed */
u8 nOverflow; /* Number of overflow cell bodies in aCell[] */
u8 intKey; /* True if intkey flag is set */
u8 leaf; /* True if leaf flag is set */
u8 hasData; /* True if this page stores data */
u8 hdrOffset; /* 100 for page 1. 0 otherwise */
u8 childPtrSize; /* 0 if leaf==1. 4 if leaf==0 */
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 */
u16 idxParent; /* Index in parent of this node */
u16 nFree; /* Number of free bytes on the page */
u16 nCell; /* Number of cells on this page, local and ovfl */
u16 maskPage; /* Mask for page offset */
struct _OvflCell { /* Cells that will not fit on aData[] */
u8 *pCell; /* Pointers to the body of the overflow cell */
u16 idx; /* Insert this cell before idx-th non-overflow cell */
} aOvfl[5];
BtShared *pBt; /* Pointer to BtShared that this page is part of */
u8 *aData; /* Pointer to disk image of the page data */
DbPage *pDbPage; /* Pager page handle */
Pgno pgno; /* Page number for this page */
MemPage *pParent; /* The parent of this page. NULL for root */
};
/*
** The in-memory image of a disk page has the auxiliary information appended
** to the end. EXTRA_SIZE is the number of bytes of space needed to hold
** that extra information.
*/
#define EXTRA_SIZE sizeof(MemPage)
/* 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 contection
** has it own pointer to 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
sqlite-amalgamation.c view on Meta::CPAN
/* Opcode: NotNull P1 P2 * * *
**
** Jump to P2 if the value in register P1 is not NULL.
*/
case OP_NotNull: { /* same as TK_NOTNULL, jump, in1 */
if( (pIn1->flags & MEM_Null)==0 ){
pc = pOp->p2 - 1;
}
break;
}
/* Opcode: SetNumColumns * P2 * * *
**
** This opcode sets the number of columns for the cursor opened by the
** following instruction to P2.
**
** An OP_SetNumColumns is only useful if it occurs immediately before
** one of the following opcodes:
**
** OpenRead
** OpenWrite
** OpenPseudo
**
** If the OP_Column opcode is to be executed on a cursor, then
** this opcode must be present immediately before the opcode that
** opens the cursor.
*/
case OP_SetNumColumns: {
break;
}
/* Opcode: Column P1 P2 P3 P4 *
**
** 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 that (P2+1)
** values in the record, extract a NULL.
**
** The value extracted is stored in register P3.
**
** If the KeyAsData opcode has previously executed on this cursor, then the
** field might be extracted from the key rather than the data.
**
** If the column 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.
*/
case OP_Column: {
u32 payloadSize; /* Number of bytes in the record */
int p1 = pOp->p1; /* P1 value of the opcode */
int p2 = pOp->p2; /* column number to retrieve */
Cursor *pC = 0; /* The VDBE cursor */
char *zRec; /* Pointer to complete record-data */
BtCursor *pCrsr; /* The BTree cursor */
u32 *aType; /* aType[i] holds the numeric type of the i-th column */
u32 *aOffset; /* aOffset[i] is offset to start of data for i-th column */
u32 nField; /* number of fields in the record */
int len; /* The length of the serialized data for the column */
int i; /* Loop counter */
char *zData; /* Part of the record being decoded */
Mem *pDest; /* Where to write the extracted value */
Mem sMem; /* For storing the record being decoded */
sMem.flags = 0;
sMem.db = 0;
sMem.zMalloc = 0;
assert( p1<p->nCursor );
assert( pOp->p3>0 && pOp->p3<=p->nMem );
pDest = &p->aMem[pOp->p3];
MemSetTypeFlag(pDest, MEM_Null);
/* This block sets the variable payloadSize to be the total number of
** bytes in the record.
**
** zRec is set to be the complete text of the record if it is available.
** The complete record text is always available for pseudo-tables
** If the record is stored in a cursor, the complete record text
** might be available in the pC->aRow cache. Or it might not be.
** If the data is unavailable, zRec is set to NULL.
**
** We also compute the number of columns in the record. For cursors,
** the number of columns is stored in the Cursor.nField element.
*/
pC = p->apCsr[p1];
assert( pC!=0 );
#ifndef SQLITE_OMIT_VIRTUALTABLE
assert( pC->pVtabCursor==0 );
#endif
if( pC->pCursor!=0 ){
/* The record is stored in a B-Tree */
rc = sqlite3VdbeCursorMoveto(pC);
if( rc ) goto abort_due_to_error;
zRec = 0;
pCrsr = pC->pCursor;
if( pC->nullRow ){
payloadSize = 0;
}else if( pC->cacheStatus==p->cacheCtr ){
payloadSize = pC->payloadSize;
zRec = (char*)pC->aRow;
}else if( pC->isIndex ){
i64 payloadSize64;
sqlite3BtreeKeySize(pCrsr, &payloadSize64);
payloadSize = payloadSize64;
}else{
sqlite3BtreeDataSize(pCrsr, &payloadSize);
}
nField = pC->nField;
}else{
assert( pC->pseudoTable );
/* The record is the sole entry of a pseudo-table */
payloadSize = pC->nData;
zRec = pC->pData;
pC->cacheStatus = CACHE_STALE;
assert( payloadSize==0 || zRec!=0 );
nField = pC->nField;
pCrsr = 0;
}
/* If payloadSize is 0, then just store a NULL */
if( payloadSize==0 ){
assert( pDest->flags&MEM_Null );
goto op_column_out;
sqlite-amalgamation.c view on Meta::CPAN
/*
** 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
*/
static int xferCompatibleIndex(Index *pDest, Index *pSrc){
int i;
assert( pDest && pSrc );
assert( pDest->pTable!=pSrc->pTable );
if( pDest->nColumn!=pSrc->nColumn ){
return 0; /* Different number of columns */
}
if( pDest->onError!=pSrc->onError ){
return 0; /* Different conflict resolution strategies */
}
for(i=0; i<pSrc->nColumn; i++){
if( pSrc->aiColumn[i]!=pDest->aiColumn[i] ){
return 0; /* Different columns indexed */
}
if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){
return 0; /* Different sort orders */
}
if( pSrc->azColl[i]!=pDest->azColl[i] ){
return 0; /* Different collating sequences */
}
}
/* If no test above fails then the indices must be compatible */
return 1;
}
/*
** Attempt the transfer optimization on INSERTs of the form
**
** INSERT INTO tab1 SELECT * FROM tab2;
**
** This optimization is only attempted if
**
** (1) tab1 and tab2 have identical schemas including all the
** same indices and constraints
**
** (2) tab1 and tab2 are different tables
**
** (3) There must be no triggers on tab1
**
** (4) The result set of the SELECT statement is "*"
**
** (5) The SELECT statement has no WHERE, HAVING, ORDER BY, GROUP BY,
** or LIMIT clause.
**
** (6) The SELECT statement is a simple (not a compound) select that
** contains only tab2 in its FROM clause
**
** This method for implementing the INSERT transfers raw records from
** tab2 over to tab1. The columns are not decoded. Raw records from
** the indices of tab2 are transfered to tab1 as well. In so doing,
** the resulting tab1 has much less fragmentation.
**
** This routine returns TRUE if the optimization is attempted. If any
** of the conditions above fail so that the optimization should not
** be attempted, then this routine returns FALSE.
*/
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 */
){
ExprList *pEList; /* The result set of the SELECT */
Table *pSrc; /* The table in the FROM clause of SELECT */
Index *pSrcIdx, *pDestIdx; /* Source and destination indices */
struct SrcList_item *pItem; /* An element of pSelect->pSrc */
int i; /* Loop counter */
int iDbSrc; /* The database of pSrc */
int iSrc, iDest; /* Cursors from source and destination */
int addr1, addr2; /* Loop addresses */
int emptyDestTest; /* Address of test for empty pDest */
int emptySrcTest; /* Address of test for empty pSrc */
Vdbe *v; /* The VDBE we are building */
KeyInfo *pKey; /* Key information for an index */
int regAutoinc; /* Memory register used by AUTOINC */
int destHasUniqueIdx = 0; /* True if pDest has a UNIQUE index */
int regData, regRowid; /* Registers holding data and rowid */
if( pSelect==0 ){
return 0; /* Must be of the form INSERT INTO ... SELECT ... */
}
if( pDest->pTrigger ){
return 0; /* tab1 must not have triggers */
}
#ifndef SQLITE_OMIT_VIRTUALTABLE
if( pDest->isVirtual ){
return 0; /* tab1 must not be a virtual table */
}
#endif
if( onError==OE_Default ){
onError = OE_Abort;
}
if( onError!=OE_Abort && onError!=OE_Rollback ){
return 0; /* Cannot do OR REPLACE or OR IGNORE or OR FAIL */
}
assert(pSelect->pSrc); /* allocated even if there is no FROM clause */
if( pSelect->pSrc->nSrc!=1 ){
return 0; /* FROM clause must have exactly one term */
}
if( pSelect->pSrc->a[0].pSelect ){
return 0; /* FROM clause cannot contain a subquery */
}
if( pSelect->pWhere ){
return 0; /* SELECT may not have a WHERE clause */
}
if( pSelect->pOrderBy ){
return 0; /* SELECT may not have an ORDER BY clause */
}
sqlite-amalgamation.c view on Meta::CPAN
int n = fts3GetVarint(pReader->pData, &iDummy);
assert( !dlrAtEnd(pReader) );
return pReader->pData+n;
}
static int dlrPosDataLen(DLReader *pReader){
sqlite_int64 iDummy;
int n = fts3GetVarint(pReader->pData, &iDummy);
assert( !dlrAtEnd(pReader) );
return pReader->nElement-n;
}
static void dlrStep(DLReader *pReader){
assert( !dlrAtEnd(pReader) );
/* Skip past current doclist element. */
assert( pReader->nElement<=pReader->nData );
pReader->pData += pReader->nElement;
pReader->nData -= pReader->nElement;
/* If there is more data, read the next doclist element. */
if( pReader->nData!=0 ){
sqlite_int64 iDocidDelta;
int iDummy, n = fts3GetVarint(pReader->pData, &iDocidDelta);
pReader->iDocid += iDocidDelta;
if( pReader->iType>=DL_POSITIONS ){
assert( n<pReader->nData );
while( 1 ){
n += fts3GetVarint32(pReader->pData+n, &iDummy);
assert( n<=pReader->nData );
if( iDummy==POS_END ) break;
if( iDummy==POS_COLUMN ){
n += fts3GetVarint32(pReader->pData+n, &iDummy);
assert( n<pReader->nData );
}else if( pReader->iType==DL_POSITIONS_OFFSETS ){
n += fts3GetVarint32(pReader->pData+n, &iDummy);
n += fts3GetVarint32(pReader->pData+n, &iDummy);
assert( n<pReader->nData );
}
}
}
pReader->nElement = n;
assert( pReader->nElement<=pReader->nData );
}
}
static void dlrInit(DLReader *pReader, DocListType iType,
const char *pData, int nData){
assert( pData!=NULL && nData!=0 );
pReader->iType = iType;
pReader->pData = pData;
pReader->nData = nData;
pReader->nElement = 0;
pReader->iDocid = 0;
/* Load the first element's data. There must be a first element. */
dlrStep(pReader);
}
static void dlrDestroy(DLReader *pReader){
SCRAMBLE(pReader);
}
#ifndef NDEBUG
/* Verify that the doclist can be validly decoded. Also returns the
** last docid found because it is convenient in other assertions for
** DLWriter.
*/
static void docListValidate(DocListType iType, const char *pData, int nData,
sqlite_int64 *pLastDocid){
sqlite_int64 iPrevDocid = 0;
assert( nData>0 );
assert( pData!=0 );
assert( pData+nData>pData );
while( nData!=0 ){
sqlite_int64 iDocidDelta;
int n = fts3GetVarint(pData, &iDocidDelta);
iPrevDocid += iDocidDelta;
if( iType>DL_DOCIDS ){
int iDummy;
while( 1 ){
n += fts3GetVarint32(pData+n, &iDummy);
if( iDummy==POS_END ) break;
if( iDummy==POS_COLUMN ){
n += fts3GetVarint32(pData+n, &iDummy);
}else if( iType>DL_POSITIONS ){
n += fts3GetVarint32(pData+n, &iDummy);
n += fts3GetVarint32(pData+n, &iDummy);
}
assert( n<=nData );
}
}
assert( n<=nData );
pData += n;
nData -= n;
}
if( pLastDocid ) *pLastDocid = iPrevDocid;
}
#define ASSERT_VALID_DOCLIST(i, p, n, o) docListValidate(i, p, n, o)
#else
#define ASSERT_VALID_DOCLIST(i, p, n, o) assert( 1 )
#endif
/*******************************************************************/
/* DLWriter is used to write doclist data to a DataBuffer. DLWriter
** always appends to the buffer and does not own it.
**
** dlwInit - initialize to write a given type doclistto a buffer.
** dlwDestroy - clear the writer's memory. Does not free buffer.
** dlwAppend - append raw doclist data to buffer.
** dlwCopy - copy next doclist from reader to writer.
** dlwAdd - construct doclist element and append to buffer.
** Only apply dlwAdd() to DL_DOCIDS doclists (else use PLWriter).
*/
typedef struct DLWriter {
DocListType iType;
DataBuffer *b;
sqlite_int64 iPrevDocid;
#ifndef NDEBUG
int has_iPrevDocid;
#endif
} DLWriter;
static void dlwInit(DLWriter *pWriter, DocListType iType, DataBuffer *b){
pWriter->b = b;
pWriter->iType = iType;
pWriter->iPrevDocid = 0;
#ifndef NDEBUG
pWriter->has_iPrevDocid = 0;
#endif
}
static void dlwDestroy(DLWriter *pWriter){
SCRAMBLE(pWriter);
}
/* iFirstDocid is the first docid in the doclist in pData. It is
** needed because pData may point within a larger doclist, in which
** case the first item would be delta-encoded.
**
** iLastDocid is the final docid in the doclist in pData. It is
** needed to create the new iPrevDocid for future delta-encoding. The
** code could decode the passed doclist to recreate iLastDocid, but
** the only current user (docListMerge) already has decoded this
** information.
*/
/* TODO(shess) This has become just a helper for docListMerge.
** Consider a refactor to make this cleaner.
*/
static void dlwAppend(DLWriter *pWriter,
const char *pData, int nData,
sqlite_int64 iFirstDocid, sqlite_int64 iLastDocid){
sqlite_int64 iDocid = 0;
char c[VARINT_MAX];
int nFirstOld, nFirstNew; /* Old and new varint len of first docid. */
#ifndef NDEBUG
sqlite_int64 iLastDocidDelta;
#endif
/* Recode the initial docid as delta from iPrevDocid. */
nFirstOld = fts3GetVarint(pData, &iDocid);
assert( nFirstOld<nData || (nFirstOld==nData && pWriter->iType==DL_DOCIDS) );
nFirstNew = fts3PutVarint(c, iFirstDocid-pWriter->iPrevDocid);
/* Verify that the incoming doclist is valid AND that it ends with
** the expected docid. This is essential because we'll trust this
** docid in future delta-encoding.
*/
ASSERT_VALID_DOCLIST(pWriter->iType, pData, nData, &iLastDocidDelta);
assert( iLastDocid==iFirstDocid-iDocid+iLastDocidDelta );
/* Append recoded initial docid and everything else. Rest of docids
** should have been delta-encoded from previous initial docid.
*/
if( nFirstOld<nData ){
dataBufferAppend2(pWriter->b, c, nFirstNew,
pData+nFirstOld, nData-nFirstOld);
}else{
dataBufferAppend(pWriter->b, c, nFirstNew);
}
pWriter->iPrevDocid = iLastDocid;
}
static void dlwCopy(DLWriter *pWriter, DLReader *pReader){
dlwAppend(pWriter, dlrDocData(pReader), dlrDocDataBytes(pReader),
dlrDocid(pReader), dlrDocid(pReader));
}
static void dlwAdd(DLWriter *pWriter, sqlite_int64 iDocid){
char c[VARINT_MAX];
int n = fts3PutVarint(c, iDocid-pWriter->iPrevDocid);
/* Docids must ascend. */
assert( !pWriter->has_iPrevDocid || iDocid>pWriter->iPrevDocid );
assert( pWriter->iType==DL_DOCIDS );
dataBufferAppend(pWriter->b, c, n);
pWriter->iPrevDocid = iDocid;
#ifndef NDEBUG
pWriter->has_iPrevDocid = 1;
#endif
}
/*******************************************************************/
/* PLReader is used to read data from a document's position list. As
** the caller steps through the list, data is cached so that varints
** only need to be decoded once.
**
** plrInit, plrDestroy - create/destroy a reader.
** plrColumn, plrPosition, plrStartOffset, plrEndOffset - accessors
** plrAtEnd - at end of stream, only call plrDestroy once true.
** plrStep - step to the next element.
*/
typedef struct PLReader {
/* These refer to the next position's data. nData will reach 0 when
** reading the last position, so plrStep() signals EOF by setting
** pData to NULL.
*/
const char *pData;
int nData;
DocListType iType;
int iColumn; /* the last column read */
int iPosition; /* the last position read */
int iStartOffset; /* the last start offset read */
int iEndOffset; /* the last end offset read */
} PLReader;
static int plrAtEnd(PLReader *pReader){
return pReader->pData==NULL;
}
static int plrColumn(PLReader *pReader){
assert( !plrAtEnd(pReader) );
return pReader->iColumn;
}
static int plrPosition(PLReader *pReader){
assert( !plrAtEnd(pReader) );
return pReader->iPosition;
}
static int plrStartOffset(PLReader *pReader){
assert( !plrAtEnd(pReader) );
return pReader->iStartOffset;
}
static int plrEndOffset(PLReader *pReader){
assert( !plrAtEnd(pReader) );
return pReader->iEndOffset;
}
static void plrStep(PLReader *pReader){
int i, n;
assert( !plrAtEnd(pReader) );
if( pReader->nData==0 ){
pReader->pData = NULL;
return;
}
n = fts3GetVarint32(pReader->pData, &i);
if( i==POS_COLUMN ){
n += fts3GetVarint32(pReader->pData+n, &pReader->iColumn);
pReader->iPosition = 0;
pReader->iStartOffset = 0;
n += fts3GetVarint32(pReader->pData+n, &i);
}
/* Should never see adjacent column changes. */
assert( i!=POS_COLUMN );
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