| /* |
| ** 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 */ |
| 0 /* xIntegrity */ |
| }; |
| 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) */ |