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| 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 #ifndef SQLITE_CORE |
| 32 SQLITE_EXTENSION_INIT1 |
| 33 #endif |
| 34 |
| 35 #include "fts2_hash.h" |
| 36 #include "fts2_tokenizer.h" |
| 37 #include <assert.h> |
| 38 #include <stddef.h> |
| 39 |
| 40 /* |
| 41 ** Implementation of the SQL scalar function for accessing the underlying |
| 42 ** hash table. This function may be called as follows: |
| 43 ** |
| 44 ** SELECT <function-name>(<key-name>); |
| 45 ** SELECT <function-name>(<key-name>, <pointer>); |
| 46 ** |
| 47 ** where <function-name> is the name passed as the second argument |
| 48 ** to the sqlite3Fts2InitHashTable() function (e.g. 'fts2_tokenizer'). |
| 49 ** |
| 50 ** If the <pointer> argument is specified, it must be a blob value |
| 51 ** containing a pointer to be stored as the hash data corresponding |
| 52 ** to the string <key-name>. If <pointer> is not specified, then |
| 53 ** the string <key-name> must already exist in the has table. Otherwise, |
| 54 ** an error is returned. |
| 55 ** |
| 56 ** Whether or not the <pointer> argument is specified, the value returned |
| 57 ** is a blob containing the pointer stored as the hash data corresponding |
| 58 ** to string <key-name> (after the hash-table is updated, if applicable). |
| 59 */ |
| 60 static void scalarFunc( |
| 61 sqlite3_context *context, |
| 62 int argc, |
| 63 sqlite3_value **argv |
| 64 ){ |
| 65 fts2Hash *pHash; |
| 66 void *pPtr = 0; |
| 67 const unsigned char *zName; |
| 68 int nName; |
| 69 |
| 70 assert( argc==1 || argc==2 ); |
| 71 |
| 72 pHash = (fts2Hash *)sqlite3_user_data(context); |
| 73 |
| 74 zName = sqlite3_value_text(argv[0]); |
| 75 nName = sqlite3_value_bytes(argv[0])+1; |
| 76 |
| 77 if( argc==2 ){ |
| 78 void *pOld; |
| 79 int n = sqlite3_value_bytes(argv[1]); |
| 80 if( n!=sizeof(pPtr) ){ |
| 81 sqlite3_result_error(context, "argument type mismatch", -1); |
| 82 return; |
| 83 } |
| 84 pPtr = *(void **)sqlite3_value_blob(argv[1]); |
| 85 pOld = sqlite3Fts2HashInsert(pHash, (void *)zName, nName, pPtr); |
| 86 if( pOld==pPtr ){ |
| 87 sqlite3_result_error(context, "out of memory", -1); |
| 88 return; |
| 89 } |
| 90 }else{ |
| 91 pPtr = sqlite3Fts2HashFind(pHash, zName, nName); |
| 92 if( !pPtr ){ |
| 93 char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName); |
| 94 sqlite3_result_error(context, zErr, -1); |
| 95 sqlite3_free(zErr); |
| 96 return; |
| 97 } |
| 98 } |
| 99 |
| 100 sqlite3_result_blob(context, (void *)&pPtr, sizeof(pPtr), SQLITE_TRANSIENT); |
| 101 } |
| 102 |
| 103 #ifdef SQLITE_TEST |
| 104 |
| 105 #include <tcl.h> |
| 106 #include <string.h> |
| 107 |
| 108 /* |
| 109 ** Implementation of a special SQL scalar function for testing tokenizers |
| 110 ** designed to be used in concert with the Tcl testing framework. This |
| 111 ** function must be called with two arguments: |
| 112 ** |
| 113 ** SELECT <function-name>(<key-name>, <input-string>); |
| 114 ** SELECT <function-name>(<key-name>, <pointer>); |
| 115 ** |
| 116 ** where <function-name> is the name passed as the second argument |
| 117 ** to the sqlite3Fts2InitHashTable() function (e.g. 'fts2_tokenizer') |
| 118 ** concatenated with the string '_test' (e.g. 'fts2_tokenizer_test'). |
| 119 ** |
| 120 ** The return value is a string that may be interpreted as a Tcl |
| 121 ** list. For each token in the <input-string>, three elements are |
| 122 ** added to the returned list. The first is the token position, the |
| 123 ** second is the token text (folded, stemmed, etc.) and the third is the |
| 124 ** substring of <input-string> associated with the token. For example, |
| 125 ** using the built-in "simple" tokenizer: |
| 126 ** |
| 127 ** SELECT fts_tokenizer_test('simple', 'I don't see how'); |
| 128 ** |
| 129 ** will return the string: |
| 130 ** |
| 131 ** "{0 i I 1 dont don't 2 see see 3 how how}" |
| 132 ** |
| 133 */ |
| 134 static void testFunc( |
| 135 sqlite3_context *context, |
| 136 int argc, |
| 137 sqlite3_value **argv |
| 138 ){ |
| 139 fts2Hash *pHash; |
| 140 sqlite3_tokenizer_module *p; |
| 141 sqlite3_tokenizer *pTokenizer = 0; |
| 142 sqlite3_tokenizer_cursor *pCsr = 0; |
| 143 |
| 144 const char *zErr = 0; |
| 145 |
| 146 const char *zName; |
| 147 int nName; |
| 148 const char *zInput; |
| 149 int nInput; |
| 150 |
| 151 const char *zArg = 0; |
| 152 |
| 153 const char *zToken; |
| 154 int nToken; |
| 155 int iStart; |
| 156 int iEnd; |
| 157 int iPos; |
| 158 |
| 159 Tcl_Obj *pRet; |
| 160 |
| 161 assert( argc==2 || argc==3 ); |
| 162 |
| 163 nName = sqlite3_value_bytes(argv[0]); |
| 164 zName = (const char *)sqlite3_value_text(argv[0]); |
| 165 nInput = sqlite3_value_bytes(argv[argc-1]); |
| 166 zInput = (const char *)sqlite3_value_text(argv[argc-1]); |
| 167 |
| 168 if( argc==3 ){ |
| 169 zArg = (const char *)sqlite3_value_text(argv[1]); |
| 170 } |
| 171 |
| 172 pHash = (fts2Hash *)sqlite3_user_data(context); |
| 173 p = (sqlite3_tokenizer_module *)sqlite3Fts2HashFind(pHash, zName, nName+1); |
| 174 |
| 175 if( !p ){ |
| 176 char *zErr = sqlite3_mprintf("unknown tokenizer: %s", zName); |
| 177 sqlite3_result_error(context, zErr, -1); |
| 178 sqlite3_free(zErr); |
| 179 return; |
| 180 } |
| 181 |
| 182 pRet = Tcl_NewObj(); |
| 183 Tcl_IncrRefCount(pRet); |
| 184 |
| 185 if( SQLITE_OK!=p->xCreate(zArg ? 1 : 0, &zArg, &pTokenizer) ){ |
| 186 zErr = "error in xCreate()"; |
| 187 goto finish; |
| 188 } |
| 189 pTokenizer->pModule = p; |
| 190 if( SQLITE_OK!=p->xOpen(pTokenizer, zInput, nInput, &pCsr) ){ |
| 191 zErr = "error in xOpen()"; |
| 192 goto finish; |
| 193 } |
| 194 pCsr->pTokenizer = pTokenizer; |
| 195 |
| 196 while( SQLITE_OK==p->xNext(pCsr, &zToken, &nToken, &iStart, &iEnd, &iPos) ){ |
| 197 Tcl_ListObjAppendElement(0, pRet, Tcl_NewIntObj(iPos)); |
| 198 Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken)); |
| 199 zToken = &zInput[iStart]; |
| 200 nToken = iEnd-iStart; |
| 201 Tcl_ListObjAppendElement(0, pRet, Tcl_NewStringObj(zToken, nToken)); |
| 202 } |
| 203 |
| 204 if( SQLITE_OK!=p->xClose(pCsr) ){ |
| 205 zErr = "error in xClose()"; |
| 206 goto finish; |
| 207 } |
| 208 if( SQLITE_OK!=p->xDestroy(pTokenizer) ){ |
| 209 zErr = "error in xDestroy()"; |
| 210 goto finish; |
| 211 } |
| 212 |
| 213 finish: |
| 214 if( zErr ){ |
| 215 sqlite3_result_error(context, zErr, -1); |
| 216 }else{ |
| 217 sqlite3_result_text(context, Tcl_GetString(pRet), -1, SQLITE_TRANSIENT); |
| 218 } |
| 219 Tcl_DecrRefCount(pRet); |
| 220 } |
| 221 |
| 222 static |
| 223 int registerTokenizer( |
| 224 sqlite3 *db, |
| 225 char *zName, |
| 226 const sqlite3_tokenizer_module *p |
| 227 ){ |
| 228 int rc; |
| 229 sqlite3_stmt *pStmt; |
| 230 const char zSql[] = "SELECT fts2_tokenizer(?, ?)"; |
| 231 |
| 232 rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0); |
| 233 if( rc!=SQLITE_OK ){ |
| 234 return rc; |
| 235 } |
| 236 |
| 237 sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC); |
| 238 sqlite3_bind_blob(pStmt, 2, &p, sizeof(p), SQLITE_STATIC); |
| 239 sqlite3_step(pStmt); |
| 240 |
| 241 return sqlite3_finalize(pStmt); |
| 242 } |
| 243 |
| 244 static |
| 245 int queryFts2Tokenizer( |
| 246 sqlite3 *db, |
| 247 char *zName, |
| 248 const sqlite3_tokenizer_module **pp |
| 249 ){ |
| 250 int rc; |
| 251 sqlite3_stmt *pStmt; |
| 252 const char zSql[] = "SELECT fts2_tokenizer(?)"; |
| 253 |
| 254 *pp = 0; |
| 255 rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0); |
| 256 if( rc!=SQLITE_OK ){ |
| 257 return rc; |
| 258 } |
| 259 |
| 260 sqlite3_bind_text(pStmt, 1, zName, -1, SQLITE_STATIC); |
| 261 if( SQLITE_ROW==sqlite3_step(pStmt) ){ |
| 262 if( sqlite3_column_type(pStmt, 0)==SQLITE_BLOB ){ |
| 263 memcpy(pp, sqlite3_column_blob(pStmt, 0), sizeof(*pp)); |
| 264 } |
| 265 } |
| 266 |
| 267 return sqlite3_finalize(pStmt); |
| 268 } |
| 269 |
| 270 void sqlite3Fts2SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule); |
| 271 |
| 272 /* |
| 273 ** Implementation of the scalar function fts2_tokenizer_internal_test(). |
| 274 ** This function is used for testing only, it is not included in the |
| 275 ** build unless SQLITE_TEST is defined. |
| 276 ** |
| 277 ** The purpose of this is to test that the fts2_tokenizer() function |
| 278 ** can be used as designed by the C-code in the queryFts2Tokenizer and |
| 279 ** registerTokenizer() functions above. These two functions are repeated |
| 280 ** in the README.tokenizer file as an example, so it is important to |
| 281 ** test them. |
| 282 ** |
| 283 ** To run the tests, evaluate the fts2_tokenizer_internal_test() scalar |
| 284 ** function with no arguments. An assert() will fail if a problem is |
| 285 ** detected. i.e.: |
| 286 ** |
| 287 ** SELECT fts2_tokenizer_internal_test(); |
| 288 ** |
| 289 */ |
| 290 static void intTestFunc( |
| 291 sqlite3_context *context, |
| 292 int argc, |
| 293 sqlite3_value **argv |
| 294 ){ |
| 295 int rc; |
| 296 const sqlite3_tokenizer_module *p1; |
| 297 const sqlite3_tokenizer_module *p2; |
| 298 sqlite3 *db = (sqlite3 *)sqlite3_user_data(context); |
| 299 |
| 300 /* Test the query function */ |
| 301 sqlite3Fts2SimpleTokenizerModule(&p1); |
| 302 rc = queryFts2Tokenizer(db, "simple", &p2); |
| 303 assert( rc==SQLITE_OK ); |
| 304 assert( p1==p2 ); |
| 305 rc = queryFts2Tokenizer(db, "nosuchtokenizer", &p2); |
| 306 assert( rc==SQLITE_ERROR ); |
| 307 assert( p2==0 ); |
| 308 assert( 0==strcmp(sqlite3_errmsg(db), "unknown tokenizer: nosuchtokenizer") ); |
| 309 |
| 310 /* Test the storage function */ |
| 311 rc = registerTokenizer(db, "nosuchtokenizer", p1); |
| 312 assert( rc==SQLITE_OK ); |
| 313 rc = queryFts2Tokenizer(db, "nosuchtokenizer", &p2); |
| 314 assert( rc==SQLITE_OK ); |
| 315 assert( p2==p1 ); |
| 316 |
| 317 sqlite3_result_text(context, "ok", -1, SQLITE_STATIC); |
| 318 } |
| 319 |
| 320 #endif |
| 321 |
| 322 /* |
| 323 ** Set up SQL objects in database db used to access the contents of |
| 324 ** the hash table pointed to by argument pHash. The hash table must |
| 325 ** been initialised to use string keys, and to take a private copy |
| 326 ** of the key when a value is inserted. i.e. by a call similar to: |
| 327 ** |
| 328 ** sqlite3Fts2HashInit(pHash, FTS2_HASH_STRING, 1); |
| 329 ** |
| 330 ** This function adds a scalar function (see header comment above |
| 331 ** scalarFunc() in this file for details) and, if ENABLE_TABLE is |
| 332 ** defined at compilation time, a temporary virtual table (see header |
| 333 ** comment above struct HashTableVtab) to the database schema. Both |
| 334 ** provide read/write access to the contents of *pHash. |
| 335 ** |
| 336 ** The third argument to this function, zName, is used as the name |
| 337 ** of both the scalar and, if created, the virtual table. |
| 338 */ |
| 339 int sqlite3Fts2InitHashTable( |
| 340 sqlite3 *db, |
| 341 fts2Hash *pHash, |
| 342 const char *zName |
| 343 ){ |
| 344 int rc = SQLITE_OK; |
| 345 void *p = (void *)pHash; |
| 346 const int any = SQLITE_ANY; |
| 347 char *zTest = 0; |
| 348 char *zTest2 = 0; |
| 349 |
| 350 #ifdef SQLITE_TEST |
| 351 void *pdb = (void *)db; |
| 352 zTest = sqlite3_mprintf("%s_test", zName); |
| 353 zTest2 = sqlite3_mprintf("%s_internal_test", zName); |
| 354 if( !zTest || !zTest2 ){ |
| 355 rc = SQLITE_NOMEM; |
| 356 } |
| 357 #endif |
| 358 |
| 359 if( rc!=SQLITE_OK |
| 360 || (rc = sqlite3_create_function(db, zName, 1, any, p, scalarFunc, 0, 0)) |
| 361 || (rc = sqlite3_create_function(db, zName, 2, any, p, scalarFunc, 0, 0)) |
| 362 #ifdef SQLITE_TEST |
| 363 || (rc = sqlite3_create_function(db, zTest, 2, any, p, testFunc, 0, 0)) |
| 364 || (rc = sqlite3_create_function(db, zTest, 3, any, p, testFunc, 0, 0)) |
| 365 || (rc = sqlite3_create_function(db, zTest2, 0, any, pdb, intTestFunc, 0, 0)) |
| 366 #endif |
| 367 ); |
| 368 |
| 369 sqlite3_free(zTest); |
| 370 sqlite3_free(zTest2); |
| 371 return rc; |
| 372 } |
| 373 |
| 374 #endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS2) */ |
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