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| 1 /* | |
| 2 ** 2005 May 23 | |
| 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 file contains functions used to access the internal hash tables | |
| 14 ** of user defined functions and collation sequences. | |
| 15 */ | |
| 16 | |
| 17 #include "sqliteInt.h" | |
| 18 | |
| 19 /* | |
| 20 ** Invoke the 'collation needed' callback to request a collation sequence | |
| 21 ** in the encoding enc of name zName, length nName. | |
| 22 */ | |
| 23 static void callCollNeeded(sqlite3 *db, int enc, const char *zName){ | |
| 24 assert( !db->xCollNeeded || !db->xCollNeeded16 ); | |
| 25 if( db->xCollNeeded ){ | |
| 26 char *zExternal = sqlite3DbStrDup(db, zName); | |
| 27 if( !zExternal ) return; | |
| 28 db->xCollNeeded(db->pCollNeededArg, db, enc, zExternal); | |
| 29 sqlite3DbFree(db, zExternal); | |
| 30 } | |
| 31 #ifndef SQLITE_OMIT_UTF16 | |
| 32 if( db->xCollNeeded16 ){ | |
| 33 char const *zExternal; | |
| 34 sqlite3_value *pTmp = sqlite3ValueNew(db); | |
| 35 sqlite3ValueSetStr(pTmp, -1, zName, SQLITE_UTF8, SQLITE_STATIC); | |
| 36 zExternal = sqlite3ValueText(pTmp, SQLITE_UTF16NATIVE); | |
| 37 if( zExternal ){ | |
| 38 db->xCollNeeded16(db->pCollNeededArg, db, (int)ENC(db), zExternal); | |
| 39 } | |
| 40 sqlite3ValueFree(pTmp); | |
| 41 } | |
| 42 #endif | |
| 43 } | |
| 44 | |
| 45 /* | |
| 46 ** This routine is called if the collation factory fails to deliver a | |
| 47 ** collation function in the best encoding but there may be other versions | |
| 48 ** of this collation function (for other text encodings) available. Use one | |
| 49 ** of these instead if they exist. Avoid a UTF-8 <-> UTF-16 conversion if | |
| 50 ** possible. | |
| 51 */ | |
| 52 static int synthCollSeq(sqlite3 *db, CollSeq *pColl){ | |
| 53 CollSeq *pColl2; | |
| 54 char *z = pColl->zName; | |
| 55 int i; | |
| 56 static const u8 aEnc[] = { SQLITE_UTF16BE, SQLITE_UTF16LE, SQLITE_UTF8 }; | |
| 57 for(i=0; i<3; i++){ | |
| 58 pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, 0); | |
| 59 if( pColl2->xCmp!=0 ){ | |
| 60 memcpy(pColl, pColl2, sizeof(CollSeq)); | |
| 61 pColl->xDel = 0; /* Do not copy the destructor */ | |
| 62 return SQLITE_OK; | |
| 63 } | |
| 64 } | |
| 65 return SQLITE_ERROR; | |
| 66 } | |
| 67 | |
| 68 /* | |
| 69 ** This function is responsible for invoking the collation factory callback | |
| 70 ** or substituting a collation sequence of a different encoding when the | |
| 71 ** requested collation sequence is not available in the desired encoding. | |
| 72 ** | |
| 73 ** If it is not NULL, then pColl must point to the database native encoding | |
| 74 ** collation sequence with name zName, length nName. | |
| 75 ** | |
| 76 ** The return value is either the collation sequence to be used in database | |
| 77 ** db for collation type name zName, length nName, or NULL, if no collation | |
| 78 ** sequence can be found. If no collation is found, leave an error message. | |
| 79 ** | |
| 80 ** See also: sqlite3LocateCollSeq(), sqlite3FindCollSeq() | |
| 81 */ | |
| 82 CollSeq *sqlite3GetCollSeq( | |
| 83 Parse *pParse, /* Parsing context */ | |
| 84 u8 enc, /* The desired encoding for the collating sequence */ | |
| 85 CollSeq *pColl, /* Collating sequence with native encoding, or NULL */ | |
| 86 const char *zName /* Collating sequence name */ | |
| 87 ){ | |
| 88 CollSeq *p; | |
| 89 sqlite3 *db = pParse->db; | |
| 90 | |
| 91 p = pColl; | |
| 92 if( !p ){ | |
| 93 p = sqlite3FindCollSeq(db, enc, zName, 0); | |
| 94 } | |
| 95 if( !p || !p->xCmp ){ | |
| 96 /* No collation sequence of this type for this encoding is registered. | |
| 97 ** Call the collation factory to see if it can supply us with one. | |
| 98 */ | |
| 99 callCollNeeded(db, enc, zName); | |
| 100 p = sqlite3FindCollSeq(db, enc, zName, 0); | |
| 101 } | |
| 102 if( p && !p->xCmp && synthCollSeq(db, p) ){ | |
| 103 p = 0; | |
| 104 } | |
| 105 assert( !p || p->xCmp ); | |
| 106 if( p==0 ){ | |
| 107 sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName); | |
| 108 } | |
| 109 return p; | |
| 110 } | |
| 111 | |
| 112 /* | |
| 113 ** This routine is called on a collation sequence before it is used to | |
| 114 ** check that it is defined. An undefined collation sequence exists when | |
| 115 ** a database is loaded that contains references to collation sequences | |
| 116 ** that have not been defined by sqlite3_create_collation() etc. | |
| 117 ** | |
| 118 ** If required, this routine calls the 'collation needed' callback to | |
| 119 ** request a definition of the collating sequence. If this doesn't work, | |
| 120 ** an equivalent collating sequence that uses a text encoding different | |
| 121 ** from the main database is substituted, if one is available. | |
| 122 */ | |
| 123 int sqlite3CheckCollSeq(Parse *pParse, CollSeq *pColl){ | |
| 124 if( pColl ){ | |
| 125 const char *zName = pColl->zName; | |
| 126 sqlite3 *db = pParse->db; | |
| 127 CollSeq *p = sqlite3GetCollSeq(pParse, ENC(db), pColl, zName); | |
| 128 if( !p ){ | |
| 129 return SQLITE_ERROR; | |
| 130 } | |
| 131 assert( p==pColl ); | |
| 132 } | |
| 133 return SQLITE_OK; | |
| 134 } | |
| 135 | |
| 136 | |
| 137 | |
| 138 /* | |
| 139 ** Locate and return an entry from the db.aCollSeq hash table. If the entry | |
| 140 ** specified by zName and nName is not found and parameter 'create' is | |
| 141 ** true, then create a new entry. Otherwise return NULL. | |
| 142 ** | |
| 143 ** Each pointer stored in the sqlite3.aCollSeq hash table contains an | |
| 144 ** array of three CollSeq structures. The first is the collation sequence | |
| 145 ** preferred for UTF-8, the second UTF-16le, and the third UTF-16be. | |
| 146 ** | |
| 147 ** Stored immediately after the three collation sequences is a copy of | |
| 148 ** the collation sequence name. A pointer to this string is stored in | |
| 149 ** each collation sequence structure. | |
| 150 */ | |
| 151 static CollSeq *findCollSeqEntry( | |
| 152 sqlite3 *db, /* Database connection */ | |
| 153 const char *zName, /* Name of the collating sequence */ | |
| 154 int create /* Create a new entry if true */ | |
| 155 ){ | |
| 156 CollSeq *pColl; | |
| 157 pColl = sqlite3HashFind(&db->aCollSeq, zName); | |
| 158 | |
| 159 if( 0==pColl && create ){ | |
| 160 int nName = sqlite3Strlen30(zName); | |
| 161 pColl = sqlite3DbMallocZero(db, 3*sizeof(*pColl) + nName + 1); | |
| 162 if( pColl ){ | |
| 163 CollSeq *pDel = 0; | |
| 164 pColl[0].zName = (char*)&pColl[3]; | |
| 165 pColl[0].enc = SQLITE_UTF8; | |
| 166 pColl[1].zName = (char*)&pColl[3]; | |
| 167 pColl[1].enc = SQLITE_UTF16LE; | |
| 168 pColl[2].zName = (char*)&pColl[3]; | |
| 169 pColl[2].enc = SQLITE_UTF16BE; | |
| 170 memcpy(pColl[0].zName, zName, nName); | |
| 171 pColl[0].zName[nName] = 0; | |
| 172 pDel = sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, pColl); | |
| 173 | |
| 174 /* If a malloc() failure occurred in sqlite3HashInsert(), it will | |
| 175 ** return the pColl pointer to be deleted (because it wasn't added | |
| 176 ** to the hash table). | |
| 177 */ | |
| 178 assert( pDel==0 || pDel==pColl ); | |
| 179 if( pDel!=0 ){ | |
| 180 db->mallocFailed = 1; | |
| 181 sqlite3DbFree(db, pDel); | |
| 182 pColl = 0; | |
| 183 } | |
| 184 } | |
| 185 } | |
| 186 return pColl; | |
| 187 } | |
| 188 | |
| 189 /* | |
| 190 ** Parameter zName points to a UTF-8 encoded string nName bytes long. | |
| 191 ** Return the CollSeq* pointer for the collation sequence named zName | |
| 192 ** for the encoding 'enc' from the database 'db'. | |
| 193 ** | |
| 194 ** If the entry specified is not found and 'create' is true, then create a | |
| 195 ** new entry. Otherwise return NULL. | |
| 196 ** | |
| 197 ** A separate function sqlite3LocateCollSeq() is a wrapper around | |
| 198 ** this routine. sqlite3LocateCollSeq() invokes the collation factory | |
| 199 ** if necessary and generates an error message if the collating sequence | |
| 200 ** cannot be found. | |
| 201 ** | |
| 202 ** See also: sqlite3LocateCollSeq(), sqlite3GetCollSeq() | |
| 203 */ | |
| 204 CollSeq *sqlite3FindCollSeq( | |
| 205 sqlite3 *db, | |
| 206 u8 enc, | |
| 207 const char *zName, | |
| 208 int create | |
| 209 ){ | |
| 210 CollSeq *pColl; | |
| 211 if( zName ){ | |
| 212 pColl = findCollSeqEntry(db, zName, create); | |
| 213 }else{ | |
| 214 pColl = db->pDfltColl; | |
| 215 } | |
| 216 assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 ); | |
| 217 assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE ); | |
| 218 if( pColl ) pColl += enc-1; | |
| 219 return pColl; | |
| 220 } | |
| 221 | |
| 222 /* During the search for the best function definition, this procedure | |
| 223 ** is called to test how well the function passed as the first argument | |
| 224 ** matches the request for a function with nArg arguments in a system | |
| 225 ** that uses encoding enc. The value returned indicates how well the | |
| 226 ** request is matched. A higher value indicates a better match. | |
| 227 ** | |
| 228 ** If nArg is -1 that means to only return a match (non-zero) if p->nArg | |
| 229 ** is also -1. In other words, we are searching for a function that | |
| 230 ** takes a variable number of arguments. | |
| 231 ** | |
| 232 ** If nArg is -2 that means that we are searching for any function | |
| 233 ** regardless of the number of arguments it uses, so return a positive | |
| 234 ** match score for any | |
| 235 ** | |
| 236 ** The returned value is always between 0 and 6, as follows: | |
| 237 ** | |
| 238 ** 0: Not a match. | |
| 239 ** 1: UTF8/16 conversion required and function takes any number of arguments. | |
| 240 ** 2: UTF16 byte order change required and function takes any number of args. | |
| 241 ** 3: encoding matches and function takes any number of arguments | |
| 242 ** 4: UTF8/16 conversion required - argument count matches exactly | |
| 243 ** 5: UTF16 byte order conversion required - argument count matches exactly | |
| 244 ** 6: Perfect match: encoding and argument count match exactly. | |
| 245 ** | |
| 246 ** If nArg==(-2) then any function with a non-null xStep or xFunc is | |
| 247 ** a perfect match and any function with both xStep and xFunc NULL is | |
| 248 ** a non-match. | |
| 249 */ | |
| 250 #define FUNC_PERFECT_MATCH 6 /* The score for a perfect match */ | |
| 251 static int matchQuality( | |
| 252 FuncDef *p, /* The function we are evaluating for match quality */ | |
| 253 int nArg, /* Desired number of arguments. (-1)==any */ | |
| 254 u8 enc /* Desired text encoding */ | |
| 255 ){ | |
| 256 int match; | |
| 257 | |
| 258 /* nArg of -2 is a special case */ | |
| 259 if( nArg==(-2) ) return (p->xFunc==0 && p->xStep==0) ? 0 : FUNC_PERFECT_MATCH; | |
| 260 | |
| 261 /* Wrong number of arguments means "no match" */ | |
| 262 if( p->nArg!=nArg && p->nArg>=0 ) return 0; | |
| 263 | |
| 264 /* Give a better score to a function with a specific number of arguments | |
| 265 ** than to function that accepts any number of arguments. */ | |
| 266 if( p->nArg==nArg ){ | |
| 267 match = 4; | |
| 268 }else{ | |
| 269 match = 1; | |
| 270 } | |
| 271 | |
| 272 /* Bonus points if the text encoding matches */ | |
| 273 if( enc==(p->funcFlags & SQLITE_FUNC_ENCMASK) ){ | |
| 274 match += 2; /* Exact encoding match */ | |
| 275 }else if( (enc & p->funcFlags & 2)!=0 ){ | |
| 276 match += 1; /* Both are UTF16, but with different byte orders */ | |
| 277 } | |
| 278 | |
| 279 return match; | |
| 280 } | |
| 281 | |
| 282 /* | |
| 283 ** Search a FuncDefHash for a function with the given name. Return | |
| 284 ** a pointer to the matching FuncDef if found, or 0 if there is no match. | |
| 285 */ | |
| 286 static FuncDef *functionSearch( | |
| 287 FuncDefHash *pHash, /* Hash table to search */ | |
| 288 int h, /* Hash of the name */ | |
| 289 const char *zFunc, /* Name of function */ | |
| 290 int nFunc /* Number of bytes in zFunc */ | |
| 291 ){ | |
| 292 FuncDef *p; | |
| 293 for(p=pHash->a[h]; p; p=p->pHash){ | |
| 294 if( sqlite3StrNICmp(p->zName, zFunc, nFunc)==0 && p->zName[nFunc]==0 ){ | |
| 295 return p; | |
| 296 } | |
| 297 } | |
| 298 return 0; | |
| 299 } | |
| 300 | |
| 301 /* | |
| 302 ** Insert a new FuncDef into a FuncDefHash hash table. | |
| 303 */ | |
| 304 void sqlite3FuncDefInsert( | |
| 305 FuncDefHash *pHash, /* The hash table into which to insert */ | |
| 306 FuncDef *pDef /* The function definition to insert */ | |
| 307 ){ | |
| 308 FuncDef *pOther; | |
| 309 int nName = sqlite3Strlen30(pDef->zName); | |
| 310 u8 c1 = (u8)pDef->zName[0]; | |
| 311 int h = (sqlite3UpperToLower[c1] + nName) % ArraySize(pHash->a); | |
| 312 pOther = functionSearch(pHash, h, pDef->zName, nName); | |
| 313 if( pOther ){ | |
| 314 assert( pOther!=pDef && pOther->pNext!=pDef ); | |
| 315 pDef->pNext = pOther->pNext; | |
| 316 pOther->pNext = pDef; | |
| 317 }else{ | |
| 318 pDef->pNext = 0; | |
| 319 pDef->pHash = pHash->a[h]; | |
| 320 pHash->a[h] = pDef; | |
| 321 } | |
| 322 } | |
| 323 | |
| 324 | |
| 325 | |
| 326 /* | |
| 327 ** Locate a user function given a name, a number of arguments and a flag | |
| 328 ** indicating whether the function prefers UTF-16 over UTF-8. Return a | |
| 329 ** pointer to the FuncDef structure that defines that function, or return | |
| 330 ** NULL if the function does not exist. | |
| 331 ** | |
| 332 ** If the createFlag argument is true, then a new (blank) FuncDef | |
| 333 ** structure is created and liked into the "db" structure if a | |
| 334 ** no matching function previously existed. | |
| 335 ** | |
| 336 ** If nArg is -2, then the first valid function found is returned. A | |
| 337 ** function is valid if either xFunc or xStep is non-zero. The nArg==(-2) | |
| 338 ** case is used to see if zName is a valid function name for some number | |
| 339 ** of arguments. If nArg is -2, then createFlag must be 0. | |
| 340 ** | |
| 341 ** If createFlag is false, then a function with the required name and | |
| 342 ** number of arguments may be returned even if the eTextRep flag does not | |
| 343 ** match that requested. | |
| 344 */ | |
| 345 FuncDef *sqlite3FindFunction( | |
| 346 sqlite3 *db, /* An open database */ | |
| 347 const char *zName, /* Name of the function. Not null-terminated */ | |
| 348 int nName, /* Number of characters in the name */ | |
| 349 int nArg, /* Number of arguments. -1 means any number */ | |
| 350 u8 enc, /* Preferred text encoding */ | |
| 351 u8 createFlag /* Create new entry if true and does not otherwise exist */ | |
| 352 ){ | |
| 353 FuncDef *p; /* Iterator variable */ | |
| 354 FuncDef *pBest = 0; /* Best match found so far */ | |
| 355 int bestScore = 0; /* Score of best match */ | |
| 356 int h; /* Hash value */ | |
| 357 | |
| 358 assert( nArg>=(-2) ); | |
| 359 assert( nArg>=(-1) || createFlag==0 ); | |
| 360 h = (sqlite3UpperToLower[(u8)zName[0]] + nName) % ArraySize(db->aFunc.a); | |
| 361 | |
| 362 /* First search for a match amongst the application-defined functions. | |
| 363 */ | |
| 364 p = functionSearch(&db->aFunc, h, zName, nName); | |
| 365 while( p ){ | |
| 366 int score = matchQuality(p, nArg, enc); | |
| 367 if( score>bestScore ){ | |
| 368 pBest = p; | |
| 369 bestScore = score; | |
| 370 } | |
| 371 p = p->pNext; | |
| 372 } | |
| 373 | |
| 374 /* If no match is found, search the built-in functions. | |
| 375 ** | |
| 376 ** If the SQLITE_PreferBuiltin flag is set, then search the built-in | |
| 377 ** functions even if a prior app-defined function was found. And give | |
| 378 ** priority to built-in functions. | |
| 379 ** | |
| 380 ** Except, if createFlag is true, that means that we are trying to | |
| 381 ** install a new function. Whatever FuncDef structure is returned it will | |
| 382 ** have fields overwritten with new information appropriate for the | |
| 383 ** new function. But the FuncDefs for built-in functions are read-only. | |
| 384 ** So we must not search for built-ins when creating a new function. | |
| 385 */ | |
| 386 if( !createFlag && (pBest==0 || (db->flags & SQLITE_PreferBuiltin)!=0) ){ | |
| 387 FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions); | |
| 388 bestScore = 0; | |
| 389 p = functionSearch(pHash, h, zName, nName); | |
| 390 while( p ){ | |
| 391 int score = matchQuality(p, nArg, enc); | |
| 392 if( score>bestScore ){ | |
| 393 pBest = p; | |
| 394 bestScore = score; | |
| 395 } | |
| 396 p = p->pNext; | |
| 397 } | |
| 398 } | |
| 399 | |
| 400 /* If the createFlag parameter is true and the search did not reveal an | |
| 401 ** exact match for the name, number of arguments and encoding, then add a | |
| 402 ** new entry to the hash table and return it. | |
| 403 */ | |
| 404 if( createFlag && bestScore<FUNC_PERFECT_MATCH && | |
| 405 (pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){ | |
| 406 pBest->zName = (char *)&pBest[1]; | |
| 407 pBest->nArg = (u16)nArg; | |
| 408 pBest->funcFlags = enc; | |
| 409 memcpy(pBest->zName, zName, nName); | |
| 410 pBest->zName[nName] = 0; | |
| 411 sqlite3FuncDefInsert(&db->aFunc, pBest); | |
| 412 } | |
| 413 | |
| 414 if( pBest && (pBest->xStep || pBest->xFunc || createFlag) ){ | |
| 415 return pBest; | |
| 416 } | |
| 417 return 0; | |
| 418 } | |
| 419 | |
| 420 /* | |
| 421 ** Free all resources held by the schema structure. The void* argument points | |
| 422 ** at a Schema struct. This function does not call sqlite3DbFree(db, ) on the | |
| 423 ** pointer itself, it just cleans up subsidiary resources (i.e. the contents | |
| 424 ** of the schema hash tables). | |
| 425 ** | |
| 426 ** The Schema.cache_size variable is not cleared. | |
| 427 */ | |
| 428 void sqlite3SchemaClear(void *p){ | |
| 429 Hash temp1; | |
| 430 Hash temp2; | |
| 431 HashElem *pElem; | |
| 432 Schema *pSchema = (Schema *)p; | |
| 433 | |
| 434 temp1 = pSchema->tblHash; | |
| 435 temp2 = pSchema->trigHash; | |
| 436 sqlite3HashInit(&pSchema->trigHash); | |
| 437 sqlite3HashClear(&pSchema->idxHash); | |
| 438 for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){ | |
| 439 sqlite3DeleteTrigger(0, (Trigger*)sqliteHashData(pElem)); | |
| 440 } | |
| 441 sqlite3HashClear(&temp2); | |
| 442 sqlite3HashInit(&pSchema->tblHash); | |
| 443 for(pElem=sqliteHashFirst(&temp1); pElem; pElem=sqliteHashNext(pElem)){ | |
| 444 Table *pTab = sqliteHashData(pElem); | |
| 445 sqlite3DeleteTable(0, pTab); | |
| 446 } | |
| 447 sqlite3HashClear(&temp1); | |
| 448 sqlite3HashClear(&pSchema->fkeyHash); | |
| 449 pSchema->pSeqTab = 0; | |
| 450 if( pSchema->schemaFlags & DB_SchemaLoaded ){ | |
| 451 pSchema->iGeneration++; | |
| 452 pSchema->schemaFlags &= ~DB_SchemaLoaded; | |
| 453 } | |
| 454 } | |
| 455 | |
| 456 /* | |
| 457 ** Find and return the schema associated with a BTree. Create | |
| 458 ** a new one if necessary. | |
| 459 */ | |
| 460 Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){ | |
| 461 Schema * p; | |
| 462 if( pBt ){ | |
| 463 p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaClear); | |
| 464 }else{ | |
| 465 p = (Schema *)sqlite3DbMallocZero(0, sizeof(Schema)); | |
| 466 } | |
| 467 if( !p ){ | |
| 468 db->mallocFailed = 1; | |
| 469 }else if ( 0==p->file_format ){ | |
| 470 sqlite3HashInit(&p->tblHash); | |
| 471 sqlite3HashInit(&p->idxHash); | |
| 472 sqlite3HashInit(&p->trigHash); | |
| 473 sqlite3HashInit(&p->fkeyHash); | |
| 474 p->enc = SQLITE_UTF8; | |
| 475 } | |
| 476 return p; | |
| 477 } | |
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Chromium Code Reviews
Issue 2363173002:
[sqlite] Remove obsolete reference version 3.8.7.4. (Closed)
