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 FTS2 module is being built as an extension 21 ** (in which case SQLITE_CORE is not defined), or 22 ** 23 ** * The FTS2 module is being built into the core of 24 ** SQLite (in which case SQLITE_ENABLE_FTS2 is defined). 25 */ 26 #if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2) 27 28 29 #include "sqlite3.h" 30 #include "sqlite3ext.h" 31 SQLITE_EXTENSION_INIT3 32 33 #include "fts2_hash.h" 34 #include "fts2_tokenizer.h" 35 #include <assert.h> 36 37 /* 38 ** Implementation of the SQL scalar function for accessing the underlying 39 ** hash table. This function may be called as follows: 40 ** 41 ** SELECT <function-name>(<key-name>); 42 ** SELECT <function-name>(<key-name>, <pointer>); 43 ** 44 ** where <function-name> is the name passed as the second argument 45 ** to the sqlite3Fts2InitHashTable() function (e.g. 'fts2_tokenizer'). 46 ** 47 ** If the <pointer> argument is specified, it must be a blob value 48 ** containing a pointer to be stored as the hash data corresponding 49 ** to the string <key-name>. If <pointer> is not specified, then 50 ** the string <key-name> must already exist in the has table. Otherwise, 51 ** an error is returned. 52 ** 53 ** Whether or not the <pointer> argument is specified, the value returned 54 ** is a blob containing the pointer stored as the hash data corresponding 55 ** to string <key-name> (after the hash-table is updated, if applicable). 56 */ 57 static void scalarFunc( 58 sqlite3_context *context, 59 int argc, 60 sqlite3_value **argv 61 ){ 62 fts2Hash *pHash; 63 void *pPtr = 0; 64 const unsigned char *zName; 65 int nName; 66 67 assert( argc==1 || argc==2 ); 68 69 pHash = (fts2Hash *)sqlite3_user_data(context); 70 71 zName = sqlite3_value_text(argv[0]); 72 nName = sqlite3_value_bytes(argv[0])+1; 73 74 if( argc==2 ){ 75 void *pOld; 76 int n = sqlite3_value_bytes(argv[1]); 77 if( n!=sizeof(pPtr) ){ 78 sqlite3_result_error(context, "argument type mismatch", -1); 79 return; 80 } 81 pPtr = *(void **)sqlite3_value_blob(argv[1]); 82 pOld = sqlite3Fts2HashInsert(pHash, (void *)zName, nName, pPtr); 83 if( pOld==pPtr ){ 84 sqlite3_result_error(context, "out of memory", -1); 85 return; 86 } 87 }else{ 88 pPtr = sqlite3Fts2HashFind(pHash, zName, nName); 89 if( !pPtr ){ 90 char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName); 91 sqlite3_result_error(context, zErr, -1); 92 sqlite3_free(zErr); 93 return; 94 } 95 } 96 97 sqlite3_result_blob(context, (void *)&pPtr, sizeof(pPtr), SQLITE_TRANSIENT); 98 } 99 100 #ifdef SQLITE_TEST 101 102 #if defined(INCLUDE_SQLITE_TCL_H) 103 # include "sqlite_tcl.h" 104 #else 105 # include "tcl.h" 106 #endif 107 #include <string.h> 108 109 /* 110 ** Implementation of a special SQL scalar function for testing tokenizers 111 ** designed to be used in concert with the Tcl testing framework. This 112 ** function must be called with two arguments: 113 ** 114 ** SELECT <function-name>(<key-name>, <input-string>); 115 ** SELECT <function-name>(<key-name>, <pointer>); 116 ** 117 ** where <function-name> is the name passed as the second argument 118 ** to the sqlite3Fts2InitHashTable() function (e.g. 'fts2_tokenizer') 119 ** concatenated with the string '_test' (e.g. 'fts2_tokenizer_test'). 120 ** 121 ** The return value is a string that may be interpreted as a Tcl 122 ** list. For each token in the <input-string>, three elements are 123 ** added to the returned list. The first is the token position, the 124 ** second is the token text (folded, stemmed, etc.) and the third is the 125 ** substring of <input-string> associated with the token. For example, 126 ** using the built-in "simple" tokenizer: 127 ** 128 ** SELECT fts_tokenizer_test('simple', 'I don't see how'); 129 ** 130 ** will return the string: 131 ** 132 ** "{0 i I 1 dont don't 2 see see 3 how how}" 133 ** 134 */ 135 static void testFunc( 136 sqlite3_context *context, 137 int argc, 138 sqlite3_value **argv 139 ){ 140 fts2Hash *pHash; 141 sqlite3_tokenizer_module *p; 142 sqlite3_tokenizer *pTokenizer = 0; 143 sqlite3_tokenizer_cursor *pCsr = 0; 144 145 const char *zErr = 0; 146 147 const char *zName; 148 int nName; 149 const char *zInput; 150 int nInput; 151 152 const char *zArg = 0; 153 154 const char *zToken; 155 int nToken; 156 int iStart; 157 int iEnd; 158 int iPos; 159 160 Tcl_Obj *pRet; 161 162 assert( argc==2 || argc==3 ); 163 164 nName = sqlite3_value_bytes(argv[0]); 165 zName = (const char *)sqlite3_value_text(argv[0]); 166 nInput = sqlite3_value_bytes(argv[argc-1]); 167 zInput = (const char *)sqlite3_value_text(argv[argc-1]); 168 169 if( argc==3 ){ 170 zArg = (const char *)sqlite3_value_text(argv[1]); 171 } 172 173 pHash = (fts2Hash *)sqlite3_user_data(context); 174 p = (sqlite3_tokenizer_module *)sqlite3Fts2HashFind(pHash, zName, nName+1); 175 176 if( !p ){ 177 char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName); 178 sqlite3_result_error(context, zErr, -1); 179 sqlite3_free(zErr); 180 return; 181 } 182 183 pRet = Tcl_NewObj(); 184 Tcl_IncrRefCount(pRet); 185 186 if( SQLITE_OK!=p->xCreate(zArg ? 1 : 0, &zArg, &pTokenizer) ){ 187 zErr = "error in xCreate()"; 188 goto finish; 189 } 190 pTokenizer->pModule = p; 191 if( SQLITE_OK!=p->xOpen(pTokenizer, zInput, nInput, &pCsr) ){ 192 zErr = "error in xOpen()"; 193 goto finish; 194 } 195 pCsr->pTokenizer = pTokenizer; 196 197 while( SQLITE_OK==p->xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos) ){ 198 Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(iPos)); 199 Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken)); 200 zToken = &zInput[iStart]; 201 nToken = iEnd-iStart; 202 Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken)); 203 } 204 205 if( SQLITE_OK!=p->xClose(pCsr) ){ 206 zErr = "error in xClose()"; 207 goto finish; 208 } 209 if( SQLITE_OK!=p->xDestroy(pTokenizer) ){ 210 zErr = "error in xDestroy()"; 211 goto finish; 212 } 213 214 finish: 215 if( zErr ){ 216 sqlite3_result_error(context, zErr, -1); 217 }else{ 218 sqlite3_result_text(context, Tcl_GetString(pRet), -1, SQLITE_TRANSIENT); 219 } 220 Tcl_DecrRefCount(pRet); 221 } 222 223 static 224 int registerTokenizer( 225 sqlite3 *db, 226 char *zName, 227 const sqlite3_tokenizer_module *p 228 ){ 229 int rc; 230 sqlite3_stmt *pStmt; 231 const char zSql[] = "SELECT fts2_tokenizer(?, ?)"; 232 233 rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0); 234 if( rc!=SQLITE_OK ){ 235 return rc; 236 } 237 238 sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC); 239 sqlite3_bind_blob(pStmt, 2, &p, sizeof(p), SQLITE_STATIC); 240 sqlite3_step(pStmt); 241 242 return sqlite3_finalize(pStmt); 243 } 244 245 static 246 int queryFts2Tokenizer( 247 sqlite3 *db, 248 char *zName, 249 const sqlite3_tokenizer_module **pp 250 ){ 251 int rc; 252 sqlite3_stmt *pStmt; 253 const char zSql[] = "SELECT fts2_tokenizer(?)"; 254 255 *pp = 0; 256 rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0); 257 if( rc!=SQLITE_OK ){ 258 return rc; 259 } 260 261 sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC); 262 if( SQLITE_ROW==sqlite3_step(pStmt) ){ 263 if( sqlite3_column_type(pStmt, 0)==SQLITE_BLOB ){ 264 memcpy(pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp)); 265 } 266 } 267 268 return sqlite3_finalize(pStmt); 269 } 270 271 void sqlite3Fts2SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule); 272 273 /* 274 ** Implementation of the scalar function fts2_tokenizer_internal_test(). 275 ** This function is used for testing only, it is not included in the 276 ** build unless SQLITE_TEST is defined. 277 ** 278 ** The purpose of this is to test that the fts2_tokenizer() function 279 ** can be used as designed by the C-code in the queryFts2Tokenizer and 280 ** registerTokenizer() functions above. These two functions are repeated 281 ** in the README.tokenizer file as an example, so it is important to 282 ** test them. 283 ** 284 ** To run the tests, evaluate the fts2_tokenizer_internal_test() scalar 285 ** function with no arguments. An assert() will fail if a problem is 286 ** detected. i.e.: 287 ** 288 ** SELECT fts2_tokenizer_internal_test(); 289 ** 290 */ 291 static void intTestFunc( 292 sqlite3_context *context, 293 int argc, 294 sqlite3_value **argv 295 ){ 296 int rc; 297 const sqlite3_tokenizer_module *p1; 298 const sqlite3_tokenizer_module *p2; 299 sqlite3 *db = (sqlite3 *)sqlite3_user_data(context); 300 301 /* Test the query function */ 302 sqlite3Fts2SimpleTokenizerModule(&p1); 303 rc = queryFts2Tokenizer(db, "simple", &p2); 304 assert( rc==SQLITE_OK ); 305 assert( p1==p2 ); 306 rc = queryFts2Tokenizer(db, "nosuchtokenizer", &p2); 307 assert( rc==SQLITE_ERROR ); 308 assert( p2==0 ); 309 assert( 0==strcmp(sqlite3_errmsg(db), "unknown tokenizer: nosuchtokenizer") ); 310 311 /* Test the storage function */ 312 rc = registerTokenizer(db, "nosuchtokenizer", p1); 313 assert( rc==SQLITE_OK ); 314 rc = queryFts2Tokenizer(db, "nosuchtokenizer", &p2); 315 assert( rc==SQLITE_OK ); 316 assert( p2==p1 ); 317 318 sqlite3_result_text(context, "ok", -1, SQLITE_STATIC); 319 } 320 321 #endif 322 323 /* 324 ** Set up SQL objects in database db used to access the contents of 325 ** the hash table pointed to by argument pHash. The hash table must 326 ** been initialized to use string keys, and to take a private copy 327 ** of the key when a value is inserted. i.e. by a call similar to: 328 ** 329 ** sqlite3Fts2HashInit(pHash, FTS2_HASH_STRING, 1); 330 ** 331 ** This function adds a scalar function (see header comment above 332 ** scalarFunc() in this file for details) and, if ENABLE_TABLE is 333 ** defined at compilation time, a temporary virtual table (see header 334 ** comment above struct HashTableVtab) to the database schema. Both 335 ** provide read/write access to the contents of *pHash. 336 ** 337 ** The third argument to this function, zName, is used as the name 338 ** of both the scalar and, if created, the virtual table. 339 */ 340 int sqlite3Fts2InitHashTable( 341 sqlite3 *db, 342 fts2Hash *pHash, 343 const char *zName 344 ){ 345 int rc = SQLITE_OK; 346 void *p = (void *)pHash; 347 const int any = SQLITE_ANY; 348 char *zTest = 0; 349 char *zTest2 = 0; 350 351 #ifdef SQLITE_TEST 352 void *pdb = (void *)db; 353 zTest = sqlite3_mprintf("%s_test", zName); 354 zTest2 = sqlite3_mprintf("%s_internal_test", zName); 355 if( !zTest || !zTest2 ){ 356 rc = SQLITE_NOMEM; 357 } 358 #endif 359 360 if( rc!=SQLITE_OK 361 || (rc = sqlite3_create_function(db, zName, 1, any, p, scalarFunc, 0, 0)) 362 || (rc = sqlite3_create_function(db, zName, 2, any, p, scalarFunc, 0, 0)) 363 #ifdef SQLITE_TEST 364 || (rc = sqlite3_create_function(db, zTest, 2, any, p, testFunc, 0, 0)) 365 || (rc = sqlite3_create_function(db, zTest, 3, any, p, testFunc, 0, 0)) 366 || (rc = sqlite3_create_function(db, zTest2, 0, any, pdb, intTestFunc, 0, 0)) 367 #endif 368 ); 369 370 sqlite3_free(zTest); 371 sqlite3_free(zTest2); 372 return rc; 373 } 374 375 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2) */ 376