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sqlcipher/ext/fts3/fts3_term.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.
**
******************************************************************************
**
** This file is not part of the production FTS code. It is only used for
** testing. It contains a virtual table implementation that provides direct
** access to the full-text index of an FTS table.
*/
#include "fts3Int.h"
#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
#ifdef SQLITE_TEST
#include <string.h>
#include <assert.h>
#include <stdlib.h>
typedef struct Fts3termTable Fts3termTable;
typedef struct Fts3termCursor Fts3termCursor;
struct Fts3termTable {
sqlite3_vtab base; /* Base class used by SQLite core */
int iIndex; /* Index for Fts3Table.aIndex[] */
Fts3Table *pFts3Tab;
};
struct Fts3termCursor {
sqlite3_vtab_cursor base; /* Base class used by SQLite core */
Fts3MultiSegReader csr; /* Must be right after "base" */
Fts3SegFilter filter;
int isEof; /* True if cursor is at EOF */
char *pNext;
sqlite3_int64 iRowid; /* Current 'rowid' value */
sqlite3_int64 iDocid; /* Current 'docid' value */
int iCol; /* Current 'col' value */
int iPos; /* Current 'pos' value */
};
/*
** Schema of the terms table.
*/
#define FTS3_TERMS_SCHEMA "CREATE TABLE x(term, docid, col, pos)"
/*
** 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 fts3termConnectMethod(
sqlite3 *db, /* Database connection */
void *pCtx, /* Non-zero for an fts4prefix 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 */
){
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() */
Fts3termTable *p; /* Virtual table object to return */
int iIndex = 0;
UNUSED_PARAMETER(pCtx);
if( argc==5 ){
iIndex = atoi(argv[4]);
argc--;
}
/* The user should specify a single argument - the name of an fts3 table. */
if( argc!=4 ){
sqlite3Fts3ErrMsg(pzErr,
"wrong number of arguments to fts4term constructor"
);
return SQLITE_ERROR;
}
zDb = argv[1];
nDb = (int)strlen(zDb);
zFts3 = argv[3];
nFts3 = (int)strlen(zFts3);
rc = sqlite3_declare_vtab(db, FTS3_TERMS_SCHEMA);
if( rc!=SQLITE_OK ) return rc;
nByte = sizeof(Fts3termTable) + sizeof(Fts3Table) + nDb + nFts3 + 2;
p = (Fts3termTable *)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 = iIndex+1;
p->iIndex = iIndex;
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;
}
/*
** 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 fts3termDisconnectMethod(sqlite3_vtab *pVtab){
Fts3termTable *p = (Fts3termTable *)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 fts3termBestIndexMethod(
sqlite3_vtab *pVTab,
sqlite3_index_info *pInfo
){
UNUSED_PARAMETER(pVTab);
/* This vtab naturally does "ORDER BY term, docid, col, pos". */
if( pInfo->nOrderBy ){
int i;
for(i=0; i<pInfo->nOrderBy; i++){
if( pInfo->aOrderBy[i].iColumn!=i || pInfo->aOrderBy[i].desc ) break;
}
if( i==pInfo->nOrderBy ){
pInfo->orderByConsumed = 1;
}
}
return SQLITE_OK;
}
/*
** xOpen - Open a cursor.
*/
static int fts3termOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
Fts3termCursor *pCsr; /* Pointer to cursor object to return */
UNUSED_PARAMETER(pVTab);
pCsr = (Fts3termCursor *)sqlite3_malloc(sizeof(Fts3termCursor));
if( !pCsr ) return SQLITE_NOMEM;
memset(pCsr, 0, sizeof(Fts3termCursor));
*ppCsr = (sqlite3_vtab_cursor *)pCsr;
return SQLITE_OK;
}
/*
** xClose - Close a cursor.
*/
static int fts3termCloseMethod(sqlite3_vtab_cursor *pCursor){
Fts3Table *pFts3 = ((Fts3termTable *)pCursor->pVtab)->pFts3Tab;
Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
sqlite3Fts3SegmentsClose(pFts3);
sqlite3Fts3SegReaderFinish(&pCsr->csr);
sqlite3_free(pCsr);
return SQLITE_OK;
}
/*
** xNext - Advance the cursor to the next row, if any.
*/
static int fts3termNextMethod(sqlite3_vtab_cursor *pCursor){
Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
Fts3Table *pFts3 = ((Fts3termTable *)pCursor->pVtab)->pFts3Tab;
int rc;
sqlite3_int64 v;
/* Increment our pretend rowid value. */
pCsr->iRowid++;
/* Advance to the next term in the full-text index. */
if( pCsr->csr.aDoclist==0
|| pCsr->pNext>=&pCsr->csr.aDoclist[pCsr->csr.nDoclist-1]
){
rc = sqlite3Fts3SegReaderStep(pFts3, &pCsr->csr);
if( rc!=SQLITE_ROW ){
pCsr->isEof = 1;
return rc;
}
pCsr->iCol = 0;
pCsr->iPos = 0;
pCsr->iDocid = 0;
pCsr->pNext = pCsr->csr.aDoclist;
/* Read docid */
pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &pCsr->iDocid);
}
pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
if( v==0 ){
pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
pCsr->iDocid += v;
pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
pCsr->iCol = 0;
pCsr->iPos = 0;
}
if( v==1 ){
pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
pCsr->iCol += (int)v;
pCsr->iPos = 0;
pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v);
}
pCsr->iPos += (int)(v - 2);
return SQLITE_OK;
}
/*
** xFilter - Initialize a cursor to point at the start of its data.
*/
static int fts3termFilterMethod(
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 */
){
Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
Fts3termTable *p = (Fts3termTable *)pCursor->pVtab;
Fts3Table *pFts3 = p->pFts3Tab;
int rc;
UNUSED_PARAMETER(nVal);
UNUSED_PARAMETER(idxNum);
UNUSED_PARAMETER(idxStr);
UNUSED_PARAMETER(apVal);
assert( idxStr==0 && idxNum==0 );
/* In case this cursor is being reused, close and zero it. */
testcase(pCsr->filter.zTerm);
sqlite3Fts3SegReaderFinish(&pCsr->csr);
memset(&pCsr->csr, 0, ((u8*)&pCsr[1]) - (u8*)&pCsr->csr);
pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
pCsr->filter.flags |= FTS3_SEGMENT_SCAN;
rc = sqlite3Fts3SegReaderCursor(pFts3, 0, p->iIndex, FTS3_SEGCURSOR_ALL,
pCsr->filter.zTerm, pCsr->filter.nTerm, 0, 1, &pCsr->csr
);
if( rc==SQLITE_OK ){
rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter);
}
if( rc==SQLITE_OK ){
rc = fts3termNextMethod(pCursor);
}
return rc;
}
/*
** xEof - Return true if the cursor is at EOF, or false otherwise.
*/
static int fts3termEofMethod(sqlite3_vtab_cursor *pCursor){
Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
return pCsr->isEof;
}
/*
** xColumn - Return a column value.
*/
static int fts3termColumnMethod(
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 */
){
Fts3termCursor *p = (Fts3termCursor *)pCursor;
assert( iCol>=0 && iCol<=3 );
switch( iCol ){
case 0:
sqlite3_result_text(pCtx, p->csr.zTerm, p->csr.nTerm, SQLITE_TRANSIENT);
break;
case 1:
sqlite3_result_int64(pCtx, p->iDocid);
break;
case 2:
sqlite3_result_int64(pCtx, p->iCol);
break;
default:
sqlite3_result_int64(pCtx, p->iPos);
break;
}
return SQLITE_OK;
}
/*
** xRowid - Return the current rowid for the cursor.
*/
static int fts3termRowidMethod(
sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
sqlite_int64 *pRowid /* OUT: Rowid value */
){
Fts3termCursor *pCsr = (Fts3termCursor *)pCursor;
*pRowid = pCsr->iRowid;
return SQLITE_OK;
}
/*
** Register the fts3term module with database connection db. Return SQLITE_OK
** if successful or an error code if sqlite3_create_module() fails.
*/
int sqlite3Fts3InitTerm(sqlite3 *db){
static const sqlite3_module fts3term_module = {
0, /* iVersion */
fts3termConnectMethod, /* xCreate */
fts3termConnectMethod, /* xConnect */
fts3termBestIndexMethod, /* xBestIndex */
fts3termDisconnectMethod, /* xDisconnect */
fts3termDisconnectMethod, /* xDestroy */
fts3termOpenMethod, /* xOpen */
fts3termCloseMethod, /* xClose */
fts3termFilterMethod, /* xFilter */
fts3termNextMethod, /* xNext */
fts3termEofMethod, /* xEof */
fts3termColumnMethod, /* xColumn */
fts3termRowidMethod, /* 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, "fts4term", &fts3term_module, 0);
return rc;
}
#endif
#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
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