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sqlcipher/ext/fts3/fts3_aux.c

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/*
** 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) */
int 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);
rc = sqlite3_declare_vtab(db, FTS3_AUX_SCHEMA);
if( rc!=SQLITE_OK ) return rc;
nByte = sizeof(Fts3auxTable) + sizeof(Fts3Table) + nDb + nFts3 + 2;
p = (Fts3auxTable *)sqlite3_malloc(nByte);
if( !p ) return SQLITE_NOMEM;
memset(p, 0, nByte);
p->pFts3Tab = (Fts3Table *)&p[1];
p->pFts3Tab->zDb = (char *)&p->pFts3Tab[1];
p->pFts3Tab->zName = &p->pFts3Tab->zDb[nDb+1];
p->pFts3Tab->db = db;
p->pFts3Tab->nIndex = 1;
memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);
memcpy((char *)p->pFts3Tab->zName, zFts3, nFts3);
sqlite3Fts3Dequote((char *)p->pFts3Tab->zName);
*ppVtab = (sqlite3_vtab *)p;
return SQLITE_OK;
bad_args:
sqlite3Fts3ErrMsg(pzErr, "invalid arguments to fts4aux constructor");
return SQLITE_ERROR;
}
/*
** 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 fts3auxDisconnectMethod(sqlite3_vtab *pVtab){
Fts3auxTable *p = (Fts3auxTable *)pVtab;
Fts3Table *pFts3 = p->pFts3Tab;
int i;
/* Free any prepared statements held */
for(i=0; i<SizeofArray(pFts3->aStmt); i++){
sqlite3_finalize(pFts3->aStmt[i]);
}
sqlite3_free(pFts3->zSegmentsTbl);
sqlite3_free(p);
return SQLITE_OK;
}
#define FTS4AUX_EQ_CONSTRAINT 1
#define FTS4AUX_GE_CONSTRAINT 2
#define FTS4AUX_LE_CONSTRAINT 4
/*
** xBestIndex - Analyze a WHERE and ORDER BY clause.
*/
static int fts3auxBestIndexMethod(
sqlite3_vtab *pVTab,
sqlite3_index_info *pInfo
){
int i;
int iEq = -1;
int iGe = -1;
int iLe = -1;
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_realloc(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;
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( fts3auxGrowStatArray(pCsr, iCol+2) ) return SQLITE_NOMEM;
pCsr->aStat[iCol+1].nDoc++;
eState = 2;
break;
}
}
pCsr->iCol = 0;
rc = SQLITE_OK;
}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);
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);
pCsr->filter.nTerm = sqlite3_value_bytes(apVal[0]);
if( pCsr->filter.zTerm==0 ) return SQLITE_NOMEM;
}
}
if( iLe>=0 ){
pCsr->zStop = sqlite3_mprintf("%s", sqlite3_value_text(apVal[iLe]));
pCsr->nStop = sqlite3_value_bytes(apVal[iLe]);
if( pCsr->zStop==0 ) return SQLITE_NOMEM;
}
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.
*/
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 */
};
int rc; /* Return code */
rc = sqlite3_create_module(db, "fts4aux", &fts3aux_module, 0);
return rc;
}
#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
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