ext/fts3/fts3_tokenizer.c

   1 /*
   2 ** 2007 June 22
   3 **
   4 ** The author disclaims copyright to this source code.  In place of
   5 ** a legal notice, here is a blessing:
   6 **
   7 **    May you do good and not evil.
   8 **    May you find forgiveness for yourself and forgive others.
   9 **    May you share freely, never taking more than you give.
  10 **
  11 ******************************************************************************
  12 **
  13 ** This is part of an SQLite module implementing full-text search.
  14 ** This particular file implements the generic tokenizer interface.
  15 */
  16
  17 /*
  18 ** The code in this file is only compiled if:
  19 **
  20 **     * The FTS3 module is being built as an extension
  21 **       (in which case SQLITE_CORE is not defined), or
  22 **
  23 **     * The FTS3 module is being built into the core of
  24 **       SQLite (in which case SQLITE_ENABLE_FTS3 is defined).
  25 */
  26 #include "fts3Int.h"
  27 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
  28
  29 #include <assert.h>
  30 #include <string.h>
  31
  32 /*
  33 ** Return true if the two-argument version of fts3_tokenizer()
  34 ** has been activated via a prior call to sqlite3_db_config(db,
  35 ** SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER, 1, 0);
  36 */
  37 static int fts3TokenizerEnabled(sqlite3_context *context){
  38   sqlite3 *db = sqlite3_context_db_handle(context);
  39   int isEnabled = 0;
  40   sqlite3_db_config(db,SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER,-1,&isEnabled);
  41   return isEnabled;
  42 }
  43
  44 /*
  45 ** Implementation of the SQL scalar function for accessing the underlying
  46 ** hash table. This function may be called as follows:
  47 **
  48 **   SELECT <function-name>(<key-name>);
  49 **   SELECT <function-name>(<key-name>, <pointer>);
  50 **
  51 ** where <function-name> is the name passed as the second argument
  52 ** to the sqlite3Fts3InitHashTable() function (e.g. 'fts3_tokenizer').
  53 **
  54 ** If the <pointer> argument is specified, it must be a blob value
  55 ** containing a pointer to be stored as the hash data corresponding
  56 ** to the string <key-name>. If <pointer> is not specified, then
  57 ** the string <key-name> must already exist in the has table. Otherwise,
  58 ** an error is returned.
  59 **
  60 ** Whether or not the <pointer> argument is specified, the value returned
  61 ** is a blob containing the pointer stored as the hash data corresponding
  62 ** to string <key-name> (after the hash-table is updated, if applicable).
  63 */
  64 static void fts3TokenizerFunc(
  65   sqlite3_context *context,
  66   int argc,
  67   sqlite3_value **argv
  68 ){
  69   Fts3Hash *pHash;
  70   void *pPtr = 0;
  71   const unsigned char *zName;
  72   int nName;
  73
  74   assert( argc==1 || argc==2 );
  75
  76   pHash = (Fts3Hash *)sqlite3_user_data(context);
  77
  78   zName = sqlite3_value_text(argv[0]);
  79   nName = sqlite3_value_bytes(argv[0])+1;
  80
  81   if( argc==2 ){
  82     if( fts3TokenizerEnabled(context) ){
  83       void *pOld;
  84       int n = sqlite3_value_bytes(argv[1]);
  85       if( zName==0 || n!=sizeof(pPtr) ){
  86         sqlite3_result_error(context, "argument type mismatch", -1);
  87         return;
  88       }
  89       pPtr = *(void **)sqlite3_value_blob(argv[1]);
  90       pOld = sqlite3Fts3HashInsert(pHash, (void *)zName, nName, pPtr);
  91       if( pOld==pPtr ){
  92         sqlite3_result_error(context, "out of memory", -1);
  93       }
  94     }else{
  95       sqlite3_result_error(context, "fts3tokenize disabled", -1);
  96       return;
  97     }
  98   }else{
  99     if( zName ){
 100       pPtr = sqlite3Fts3HashFind(pHash, zName, nName);
 101     }
 102     if( !pPtr ){
 103       char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName);
 104       sqlite3_result_error(context, zErr, -1);
 105       sqlite3_free(zErr);
 106       return;
 107     }
 108   }
 109   sqlite3_result_blob(context, (void *)&pPtr, sizeof(pPtr), SQLITE_TRANSIENT);
 110 }
 111
 112 int sqlite3Fts3IsIdChar(char c){
 113   static const char isFtsIdChar[] = {
 114       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 0x */
 115       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 1x */
 116       0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,  /* 2x */
 117       1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,  /* 3x */
 118       0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 4x */
 119       1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1,  /* 5x */
 120       0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,  /* 6x */
 121       1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,  /* 7x */
 122   };
 123   return (c&0x80 || isFtsIdChar[(int)(c)]);
 124 }
 125
 126 const char *sqlite3Fts3NextToken(const char *zStr, int *pn){
 127   const char *z1;
 128   const char *z2 = 0;
 129
 130   /* Find the start of the next token. */
 131   z1 = zStr;
 132   while( z2==0 ){
 133     char c = *z1;
 134     switch( c ){
 135       case '\0': return 0;        /* No more tokens here */
 136       case '\'':
 137       case '"':
 138       case '`': {
 139         z2 = z1;
 140         while( *++z2 && (*z2!=c || *++z2==c) );
 141         break;
 142       }
 143       case '[':
 144         z2 = &z1[1];
 145         while( *z2 && z2[0]!=']' ) z2++;
 146         if( *z2 ) z2++;
 147         break;
 148
 149       default:
 150         if( sqlite3Fts3IsIdChar(*z1) ){
 151           z2 = &z1[1];
 152           while( sqlite3Fts3IsIdChar(*z2) ) z2++;
 153         }else{
 154           z1++;
 155         }
 156     }
 157   }
 158
 159   *pn = (int)(z2-z1);
 160   return z1;
 161 }
 162
 163 int sqlite3Fts3InitTokenizer(
 164   Fts3Hash *pHash,                /* Tokenizer hash table */
 165   const char *zArg,               /* Tokenizer name */
 166   sqlite3_tokenizer **ppTok,      /* OUT: Tokenizer (if applicable) */
 167   char **pzErr                    /* OUT: Set to malloced error message */
 168 ){
 169   int rc;
 170   char *z = (char *)zArg;
 171   int n = 0;
 172   char *zCopy;
 173   char *zEnd;                     /* Pointer to nul-term of zCopy */
 174   sqlite3_tokenizer_module *m;
 175
 176   zCopy = sqlite3_mprintf("%s", zArg);
 177   if( !zCopy ) return SQLITE_NOMEM;
 178   zEnd = &zCopy[strlen(zCopy)];
 179
 180   z = (char *)sqlite3Fts3NextToken(zCopy, &n);
 181   if( z==0 ){
 182     assert( n==0 );
 183     z = zCopy;
 184   }
 185   z[n] = '\0';
 186   sqlite3Fts3Dequote(z);
 187
 188   m = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash,z,(int)strlen(z)+1);
 189   if( !m ){
 190     sqlite3Fts3ErrMsg(pzErr, "unknown tokenizer: %s", z);
 191     rc = SQLITE_ERROR;
 192   }else{
 193     char const **aArg = 0;
 194     int iArg = 0;
 195     z = &z[n+1];
 196     while( z<zEnd && (NULL!=(z = (char *)sqlite3Fts3NextToken(z, &n))) ){
 197       int nNew = sizeof(char *)*(iArg+1);
 198       char const **aNew = (const char **)sqlite3_realloc((void *)aArg, nNew);
 199       if( !aNew ){
 200         sqlite3_free(zCopy);
 201         sqlite3_free((void *)aArg);
 202         return SQLITE_NOMEM;
 203       }
 204       aArg = aNew;
 205       aArg[iArg++] = z;
 206       z[n] = '\0';
 207       sqlite3Fts3Dequote(z);
 208       z = &z[n+1];
 209     }
 210     rc = m->xCreate(iArg, aArg, ppTok);
 211     assert( rc!=SQLITE_OK || *ppTok );
 212     if( rc!=SQLITE_OK ){
 213       sqlite3Fts3ErrMsg(pzErr, "unknown tokenizer");
 214     }else{
 215       (*ppTok)->pModule = m;
 216     }
 217     sqlite3_free((void *)aArg);
 218   }
 219
 220   sqlite3_free(zCopy);
 221   return rc;
 222 }
 223
 224
 225 #ifdef SQLITE_TEST
 226
 227 #if defined(INCLUDE_SQLITE_TCL_H)
 228 #  include "sqlite_tcl.h"
 229 #else
 230 #  include "tcl.h"
 231 #endif
 232 #include <string.h>
 233
 234 /*
 235 ** Implementation of a special SQL scalar function for testing tokenizers
 236 ** designed to be used in concert with the Tcl testing framework. This
 237 ** function must be called with two or more arguments:
 238 **
 239 **   SELECT <function-name>(<key-name>, ..., <input-string>);
 240 **
 241 ** where <function-name> is the name passed as the second argument
 242 ** to the sqlite3Fts3InitHashTable() function (e.g. 'fts3_tokenizer')
 243 ** concatenated with the string '_test' (e.g. 'fts3_tokenizer_test').
 244 **
 245 ** The return value is a string that may be interpreted as a Tcl
 246 ** list. For each token in the <input-string>, three elements are
 247 ** added to the returned list. The first is the token position, the
 248 ** second is the token text (folded, stemmed, etc.) and the third is the
 249 ** substring of <input-string> associated with the token. For example,
 250 ** using the built-in "simple" tokenizer:
 251 **
 252 **   SELECT fts_tokenizer_test('simple', 'I don't see how');
 253 **
 254 ** will return the string:
 255 **
 256 **   "{0 i I 1 dont don't 2 see see 3 how how}"
 257 **
 258 */
 259 static void testFunc(
 260   sqlite3_context *context,
 261   int argc,
 262   sqlite3_value **argv
 263 ){
 264   Fts3Hash *pHash;
 265   sqlite3_tokenizer_module *p;
 266   sqlite3_tokenizer *pTokenizer = 0;
 267   sqlite3_tokenizer_cursor *pCsr = 0;
 268
 269   const char *zErr = 0;
 270
 271   const char *zName;
 272   int nName;
 273   const char *zInput;
 274   int nInput;
 275
 276   const char *azArg[64];
 277
 278   const char *zToken;
 279   int nToken = 0;
 280   int iStart = 0;
 281   int iEnd = 0;
 282   int iPos = 0;
 283   int i;
 284
 285   Tcl_Obj *pRet;
 286
 287   if( argc<2 ){
 288     sqlite3_result_error(context, "insufficient arguments", -1);
 289     return;
 290   }
 291
 292   nName = sqlite3_value_bytes(argv[0]);
 293   zName = (const char *)sqlite3_value_text(argv[0]);
 294   nInput = sqlite3_value_bytes(argv[argc-1]);
 295   zInput = (const char *)sqlite3_value_text(argv[argc-1]);
 296
 297   pHash = (Fts3Hash *)sqlite3_user_data(context);
 298   p = (sqlite3_tokenizer_module *)sqlite3Fts3HashFind(pHash, zName, nName+1);
 299
 300   if( !p ){
 301     char *zErr2 = sqlite3_mprintf("unknown tokenizer: %s", zName);
 302     sqlite3_result_error(context, zErr2, -1);
 303     sqlite3_free(zErr2);
 304     return;
 305   }
 306
 307   pRet = Tcl_NewObj();
 308   Tcl_IncrRefCount(pRet);
 309
 310   for(i=1; i<argc-1; i++){
 311     azArg[i-1] = (const char *)sqlite3_value_text(argv[i]);
 312   }
 313
 314   if( SQLITE_OK!=p->xCreate(argc-2, azArg, &pTokenizer) ){
 315     zErr = "error in xCreate()";
 316     goto finish;
 317   }
 318   pTokenizer->pModule = p;
 319   if( sqlite3Fts3OpenTokenizer(pTokenizer, 0, zInput, nInput, &pCsr) ){
 320     zErr = "error in xOpen()";
 321     goto finish;
 322   }
 323
 324   while( SQLITE_OK==p->xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos) ){
 325     Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(iPos));
 326     Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
 327     zToken = &zInput[iStart];
 328     nToken = iEnd-iStart;
 329     Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken));
 330   }
 331
 332   if( SQLITE_OK!=p->xClose(pCsr) ){
 333     zErr = "error in xClose()";
 334     goto finish;
 335   }
 336   if( SQLITE_OK!=p->xDestroy(pTokenizer) ){
 337     zErr = "error in xDestroy()";
 338     goto finish;
 339   }
 340
 341 finish:
 342   if( zErr ){
 343     sqlite3_result_error(context, zErr, -1);
 344   }else{
 345     sqlite3_result_text(context, Tcl_GetString(pRet), -1, SQLITE_TRANSIENT);
 346   }
 347   Tcl_DecrRefCount(pRet);
 348 }
 349
 350 static
 351 int registerTokenizer(
 352   sqlite3 *db,
 353   char *zName,
 354   const sqlite3_tokenizer_module *p
 355 ){
 356   int rc;
 357   sqlite3_stmt *pStmt;
 358   const char zSql[] = "SELECT fts3_tokenizer(?, ?)";
 359
 360   rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
 361   if( rc!=SQLITE_OK ){
 362     return rc;
 363   }
 364
 365   sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
 366   sqlite3_bind_blob(pStmt, 2, &p, sizeof(p), SQLITE_STATIC);
 367   sqlite3_step(pStmt);
 368
 369   return sqlite3_finalize(pStmt);
 370 }
 371
 372
 373 static
 374 int queryTokenizer(
 375   sqlite3 *db,
 376   char *zName,
 377   const sqlite3_tokenizer_module **pp
 378 ){
 379   int rc;
 380   sqlite3_stmt *pStmt;
 381   const char zSql[] = "SELECT fts3_tokenizer(?)";
 382
 383   *pp = 0;
 384   rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
 385   if( rc!=SQLITE_OK ){
 386     return rc;
 387   }
 388
 389   sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC);
 390   if( SQLITE_ROW==sqlite3_step(pStmt) ){
 391     if( sqlite3_column_type(pStmt, 0)==SQLITE_BLOB ){
 392       memcpy((void *)pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp));
 393     }
 394   }
 395
 396   return sqlite3_finalize(pStmt);
 397 }
 398
 399 void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
 400
 401 /*
 402 ** Implementation of the scalar function fts3_tokenizer_internal_test().
 403 ** This function is used for testing only, it is not included in the
 404 ** build unless SQLITE_TEST is defined.
 405 **
 406 ** The purpose of this is to test that the fts3_tokenizer() function
 407 ** can be used as designed by the C-code in the queryTokenizer and
 408 ** registerTokenizer() functions above. These two functions are repeated
 409 ** in the README.tokenizer file as an example, so it is important to
 410 ** test them.
 411 **
 412 ** To run the tests, evaluate the fts3_tokenizer_internal_test() scalar
 413 ** function with no arguments. An assert() will fail if a problem is
 414 ** detected. i.e.:
 415 **
 416 **     SELECT fts3_tokenizer_internal_test();
 417 **
 418 */
 419 static void intTestFunc(
 420   sqlite3_context *context,
 421   int argc,
 422   sqlite3_value **argv
 423 ){
 424   int rc;
 425   const sqlite3_tokenizer_module *p1;
 426   const sqlite3_tokenizer_module *p2;
 427   sqlite3 *db = (sqlite3 *)sqlite3_user_data(context);
 428
 429   UNUSED_PARAMETER(argc);
 430   UNUSED_PARAMETER(argv);
 431
 432   /* Test the query function */
 433   sqlite3Fts3SimpleTokenizerModule(&p1);
 434   rc = queryTokenizer(db, "simple", &p2);
 435   assert( rc==SQLITE_OK );
 436   assert( p1==p2 );
 437   rc = queryTokenizer(db, "nosuchtokenizer", &p2);
 438   assert( rc==SQLITE_ERROR );
 439   assert( p2==0 );
 440   assert( 0==strcmp(sqlite3_errmsg(db), "unknown tokenizer: nosuchtokenizer") );
 441
 442   /* Test the storage function */
 443   if( fts3TokenizerEnabled(context) ){
 444     rc = registerTokenizer(db, "nosuchtokenizer", p1);
 445     assert( rc==SQLITE_OK );
 446     rc = queryTokenizer(db, "nosuchtokenizer", &p2);
 447     assert( rc==SQLITE_OK );
 448     assert( p2==p1 );
 449   }
 450
 451   sqlite3_result_text(context, "ok", -1, SQLITE_STATIC);
 452 }
 453
 454 #endif
 455
 456 /*
 457 ** Set up SQL objects in database db used to access the contents of
 458 ** the hash table pointed to by argument pHash. The hash table must
 459 ** been initialized to use string keys, and to take a private copy
 460 ** of the key when a value is inserted. i.e. by a call similar to:
 461 **
 462 **    sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
 463 **
 464 ** This function adds a scalar function (see header comment above
 465 ** fts3TokenizerFunc() in this file for details) and, if ENABLE_TABLE is
 466 ** defined at compilation time, a temporary virtual table (see header
 467 ** comment above struct HashTableVtab) to the database schema. Both
 468 ** provide read/write access to the contents of *pHash.
 469 **
 470 ** The third argument to this function, zName, is used as the name
 471 ** of both the scalar and, if created, the virtual table.
 472 */
 473 int sqlite3Fts3InitHashTable(
 474   sqlite3 *db,
 475   Fts3Hash *pHash,
 476   const char *zName
 477 ){
 478   int rc = SQLITE_OK;
 479   void *p = (void *)pHash;
 480   const int any = SQLITE_ANY;
 481
 482 #ifdef SQLITE_TEST
 483   char *zTest = 0;
 484   char *zTest2 = 0;
 485   void *pdb = (void *)db;
 486   zTest = sqlite3_mprintf("%s_test", zName);
 487   zTest2 = sqlite3_mprintf("%s_internal_test", zName);
 488   if( !zTest || !zTest2 ){
 489     rc = SQLITE_NOMEM;
 490   }
 491 #endif
 492
 493   if( SQLITE_OK==rc ){
 494     rc = sqlite3_create_function(db, zName, 1, any, p, fts3TokenizerFunc, 0, 0);
 495   }
 496   if( SQLITE_OK==rc ){
 497     rc = sqlite3_create_function(db, zName, 2, any, p, fts3TokenizerFunc, 0, 0);
 498   }
 499 #ifdef SQLITE_TEST
 500   if( SQLITE_OK==rc ){
 501     rc = sqlite3_create_function(db, zTest, -1, any, p, testFunc, 0, 0);
 502   }
 503   if( SQLITE_OK==rc ){
 504     rc = sqlite3_create_function(db, zTest2, 0, any, pdb, intTestFunc, 0, 0);
 505   }
 506 #endif
 507
 508 #ifdef SQLITE_TEST
 509   sqlite3_free(zTest);
 510   sqlite3_free(zTest2);
 511 #endif
 512
 513   return rc;
 514 }
 515
 516 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */