459 lines
13 KiB
C
459 lines
13 KiB
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);
|
|
if( azDequote==0 ){
|
|
rc = SQLITE_NOMEM;
|
|
}else{
|
|
char *pSpace = (char *)&azDequote[argc];
|
|
for(i=0; i<argc; i++){
|
|
int n = (int)strlen(argv[i]);
|
|
azDequote[i] = pSpace;
|
|
memcpy(pSpace, argv[i], n+1);
|
|
sqlite3Fts3Dequote(pSpace);
|
|
pSpace += (n+1);
|
|
}
|
|
}
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Schema of the tokenizer table.
|
|
*/
|
|
#define FTS3_TOK_SCHEMA "CREATE TABLE x(input, token, start, end, position)"
|
|
|
|
/*
|
|
** 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.
|
|
**
|
|
** argv[0]: module name
|
|
** argv[1]: database name
|
|
** argv[2]: table name
|
|
** argv[3]: first argument (tokenizer name)
|
|
*/
|
|
static int fts3tokConnectMethod(
|
|
sqlite3 *db, /* Database connection */
|
|
void *pHash, /* Hash table of tokenizers */
|
|
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 */
|
|
){
|
|
Fts3tokTable *pTab = 0;
|
|
const sqlite3_tokenizer_module *pMod = 0;
|
|
sqlite3_tokenizer *pTok = 0;
|
|
int rc;
|
|
char **azDequote = 0;
|
|
int nDequote;
|
|
|
|
rc = sqlite3_declare_vtab(db, FTS3_TOK_SCHEMA);
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
|
|
nDequote = argc-3;
|
|
rc = fts3tokDequoteArray(nDequote, &argv[3], &azDequote);
|
|
|
|
if( rc==SQLITE_OK ){
|
|
const char *zModule;
|
|
if( nDequote<1 ){
|
|
zModule = "simple";
|
|
}else{
|
|
zModule = azDequote[0];
|
|
}
|
|
rc = fts3tokQueryTokenizer((Fts3Hash*)pHash, zModule, &pMod, pzErr);
|
|
}
|
|
|
|
assert( (rc==SQLITE_OK)==(pMod!=0) );
|
|
if( rc==SQLITE_OK ){
|
|
const char * const *azArg = 0;
|
|
if( nDequote>1 ) azArg = (const char * const *)&azDequote[1];
|
|
rc = pMod->xCreate((nDequote>1 ? nDequote-1 : 0), azArg, &pTok);
|
|
}
|
|
|
|
if( rc==SQLITE_OK ){
|
|
pTab = (Fts3tokTable *)sqlite3_malloc(sizeof(Fts3tokTable));
|
|
if( pTab==0 ){
|
|
rc = SQLITE_NOMEM;
|
|
}
|
|
}
|
|
|
|
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]);
|
|
int 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.
|
|
*/
|
|
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 */
|
|
};
|
|
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) */
|