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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 ** $Id: callback.c,v 1.42 2009/06/17 00:35:31 drh Exp $ | |
| 17 */ | |
| 18 | |
| 19 #include "sqliteInt.h" | |
| 20 | |
| 21 /* | |
| 22 ** Invoke the 'collation needed' callback to request a collation sequence | |
| 23 ** in the encoding enc of name zName, length nName. | |
| 24 */ | |
| 25 static void callCollNeeded(sqlite3 *db, int enc, const char *zName){ | |
| 26 assert( !db->xCollNeeded || !db->xCollNeeded16 ); | |
| 27 if( db->xCollNeeded ){ | |
| 28 char *zExternal = sqlite3DbStrDup(db, zName); | |
| 29 if( !zExternal ) return; | |
| 30 db->xCollNeeded(db->pCollNeededArg, db, enc, zExternal); | |
| 31 sqlite3DbFree(db, zExternal); | |
| 32 } | |
| 33 #ifndef SQLITE_OMIT_UTF16 | |
| 34 if( db->xCollNeeded16 ){ | |
| 35 char const *zExternal; | |
| 36 sqlite3_value *pTmp = sqlite3ValueNew(db); | |
| 37 sqlite3ValueSetStr(pTmp, -1, zName, SQLITE_UTF8, SQLITE_STATIC); | |
| 38 zExternal = sqlite3ValueText(pTmp, SQLITE_UTF16NATIVE); | |
| 39 if( zExternal ){ | |
| 40 db->xCollNeeded16(db->pCollNeededArg, db, (int)ENC(db), zExternal); | |
| 41 } | |
| 42 sqlite3ValueFree(pTmp); | |
| 43 } | |
| 44 #endif | |
| 45 } | |
| 46 | |
| 47 /* | |
| 48 ** This routine is called if the collation factory fails to deliver a | |
| 49 ** collation function in the best encoding but there may be other versions | |
| 50 ** of this collation function (for other text encodings) available. Use one | |
| 51 ** of these instead if they exist. Avoid a UTF-8 <-> UTF-16 conversion if | |
| 52 ** possible. | |
| 53 */ | |
| 54 static int synthCollSeq(sqlite3 *db, CollSeq *pColl){ | |
| 55 CollSeq *pColl2; | |
| 56 char *z = pColl->zName; | |
| 57 int i; | |
| 58 static const u8 aEnc[] = { SQLITE_UTF16BE, SQLITE_UTF16LE, SQLITE_UTF8 }; | |
| 59 for(i=0; i<3; i++){ | |
| 60 pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, 0); | |
| 61 if( pColl2->xCmp!=0 ){ | |
| 62 memcpy(pColl, pColl2, sizeof(CollSeq)); | |
| 63 pColl->xDel = 0; /* Do not copy the destructor */ | |
| 64 return SQLITE_OK; | |
| 65 } | |
| 66 } | |
| 67 return SQLITE_ERROR; | |
| 68 } | |
| 69 | |
| 70 /* | |
| 71 ** This function is responsible for invoking the collation factory callback | |
| 72 ** or substituting a collation sequence of a different encoding when the | |
| 73 ** requested collation sequence is not available in the desired encoding. | |
| 74 ** | |
| 75 ** If it is not NULL, then pColl must point to the database native encoding | |
| 76 ** collation sequence with name zName, length nName. | |
| 77 ** | |
| 78 ** The return value is either the collation sequence to be used in database | |
| 79 ** db for collation type name zName, length nName, or NULL, if no collation | |
| 80 ** sequence can be found. | |
| 81 ** | |
| 82 ** See also: sqlite3LocateCollSeq(), sqlite3FindCollSeq() | |
| 83 */ | |
| 84 CollSeq *sqlite3GetCollSeq( | |
| 85 sqlite3* db, /* The database connection */ | |
| 86 u8 enc, /* The desired encoding for the collating sequence */ | |
| 87 CollSeq *pColl, /* Collating sequence with native encoding, or NULL */ | |
| 88 const char *zName /* Collating sequence name */ | |
| 89 ){ | |
| 90 CollSeq *p; | |
| 91 | |
| 92 p = pColl; | |
| 93 if( !p ){ | |
| 94 p = sqlite3FindCollSeq(db, enc, zName, 0); | |
| 95 } | |
| 96 if( !p || !p->xCmp ){ | |
| 97 /* No collation sequence of this type for this encoding is registered. | |
| 98 ** Call the collation factory to see if it can supply us with one. | |
| 99 */ | |
| 100 callCollNeeded(db, enc, zName); | |
| 101 p = sqlite3FindCollSeq(db, enc, zName, 0); | |
| 102 } | |
| 103 if( p && !p->xCmp && synthCollSeq(db, p) ){ | |
| 104 p = 0; | |
| 105 } | |
| 106 assert( !p || p->xCmp ); | |
| 107 return p; | |
| 108 } | |
| 109 | |
| 110 /* | |
| 111 ** This routine is called on a collation sequence before it is used to | |
| 112 ** check that it is defined. An undefined collation sequence exists when | |
| 113 ** a database is loaded that contains references to collation sequences | |
| 114 ** that have not been defined by sqlite3_create_collation() etc. | |
| 115 ** | |
| 116 ** If required, this routine calls the 'collation needed' callback to | |
| 117 ** request a definition of the collating sequence. If this doesn't work, | |
| 118 ** an equivalent collating sequence that uses a text encoding different | |
| 119 ** from the main database is substituted, if one is available. | |
| 120 */ | |
| 121 int sqlite3CheckCollSeq(Parse *pParse, CollSeq *pColl){ | |
| 122 if( pColl ){ | |
| 123 const char *zName = pColl->zName; | |
| 124 sqlite3 *db = pParse->db; | |
| 125 CollSeq *p = sqlite3GetCollSeq(db, ENC(db), pColl, zName); | |
| 126 if( !p ){ | |
| 127 sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName); | |
| 128 pParse->nErr++; | |
| 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 ** prefferred 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 int nName = sqlite3Strlen30(zName); | |
| 158 pColl = sqlite3HashFind(&db->aCollSeq, zName, nName); | |
| 159 | |
| 160 if( 0==pColl && create ){ | |
| 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, nName, 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 ** The returned value is always between 0 and 6, as follows: | |
| 229 ** | |
| 230 ** 0: Not a match, or if nArg<0 and the function is has no implementation. | |
| 231 ** 1: A variable arguments function that prefers UTF-8 when a UTF-16 | |
| 232 ** encoding is requested, or vice versa. | |
| 233 ** 2: A variable arguments function that uses UTF-16BE when UTF-16LE is | |
| 234 ** requested, or vice versa. | |
| 235 ** 3: A variable arguments function using the same text encoding. | |
| 236 ** 4: A function with the exact number of arguments requested that | |
| 237 ** prefers UTF-8 when a UTF-16 encoding is requested, or vice versa. | |
| 238 ** 5: A function with the exact number of arguments requested that | |
| 239 ** prefers UTF-16LE when UTF-16BE is requested, or vice versa. | |
| 240 ** 6: An exact match. | |
| 241 ** | |
| 242 */ | |
| 243 static int matchQuality(FuncDef *p, int nArg, u8 enc){ | |
| 244 int match = 0; | |
| 245 if( p->nArg==-1 || p->nArg==nArg | |
| 246 || (nArg==-1 && (p->xFunc!=0 || p->xStep!=0)) | |
| 247 ){ | |
| 248 match = 1; | |
| 249 if( p->nArg==nArg || nArg==-1 ){ | |
| 250 match = 4; | |
| 251 } | |
| 252 if( enc==p->iPrefEnc ){ | |
| 253 match += 2; | |
| 254 } | |
| 255 else if( (enc==SQLITE_UTF16LE && p->iPrefEnc==SQLITE_UTF16BE) || | |
| 256 (enc==SQLITE_UTF16BE && p->iPrefEnc==SQLITE_UTF16LE) ){ | |
| 257 match += 1; | |
| 258 } | |
| 259 } | |
| 260 return match; | |
| 261 } | |
| 262 | |
| 263 /* | |
| 264 ** Search a FuncDefHash for a function with the given name. Return | |
| 265 ** a pointer to the matching FuncDef if found, or 0 if there is no match. | |
| 266 */ | |
| 267 static FuncDef *functionSearch( | |
| 268 FuncDefHash *pHash, /* Hash table to search */ | |
| 269 int h, /* Hash of the name */ | |
| 270 const char *zFunc, /* Name of function */ | |
| 271 int nFunc /* Number of bytes in zFunc */ | |
| 272 ){ | |
| 273 FuncDef *p; | |
| 274 for(p=pHash->a[h]; p; p=p->pHash){ | |
| 275 if( sqlite3StrNICmp(p->zName, zFunc, nFunc)==0 && p->zName[nFunc]==0 ){ | |
| 276 return p; | |
| 277 } | |
| 278 } | |
| 279 return 0; | |
| 280 } | |
| 281 | |
| 282 /* | |
| 283 ** Insert a new FuncDef into a FuncDefHash hash table. | |
| 284 */ | |
| 285 void sqlite3FuncDefInsert( | |
| 286 FuncDefHash *pHash, /* The hash table into which to insert */ | |
| 287 FuncDef *pDef /* The function definition to insert */ | |
| 288 ){ | |
| 289 FuncDef *pOther; | |
| 290 int nName = sqlite3Strlen30(pDef->zName); | |
| 291 u8 c1 = (u8)pDef->zName[0]; | |
| 292 int h = (sqlite3UpperToLower[c1] + nName) % ArraySize(pHash->a); | |
| 293 pOther = functionSearch(pHash, h, pDef->zName, nName); | |
| 294 if( pOther ){ | |
| 295 assert( pOther!=pDef && pOther->pNext!=pDef ); | |
| 296 pDef->pNext = pOther->pNext; | |
| 297 pOther->pNext = pDef; | |
| 298 }else{ | |
| 299 pDef->pNext = 0; | |
| 300 pDef->pHash = pHash->a[h]; | |
| 301 pHash->a[h] = pDef; | |
| 302 } | |
| 303 } | |
| 304 | |
| 305 | |
| 306 | |
| 307 /* | |
| 308 ** Locate a user function given a name, a number of arguments and a flag | |
| 309 ** indicating whether the function prefers UTF-16 over UTF-8. Return a | |
| 310 ** pointer to the FuncDef structure that defines that function, or return | |
| 311 ** NULL if the function does not exist. | |
| 312 ** | |
| 313 ** If the createFlag argument is true, then a new (blank) FuncDef | |
| 314 ** structure is created and liked into the "db" structure if a | |
| 315 ** no matching function previously existed. When createFlag is true | |
| 316 ** and the nArg parameter is -1, then only a function that accepts | |
| 317 ** any number of arguments will be returned. | |
| 318 ** | |
| 319 ** If createFlag is false and nArg is -1, then the first valid | |
| 320 ** function found is returned. A function is valid if either xFunc | |
| 321 ** or xStep is non-zero. | |
| 322 ** | |
| 323 ** If createFlag is false, then a function with the required name and | |
| 324 ** number of arguments may be returned even if the eTextRep flag does not | |
| 325 ** match that requested. | |
| 326 */ | |
| 327 FuncDef *sqlite3FindFunction( | |
| 328 sqlite3 *db, /* An open database */ | |
| 329 const char *zName, /* Name of the function. Not null-terminated */ | |
| 330 int nName, /* Number of characters in the name */ | |
| 331 int nArg, /* Number of arguments. -1 means any number */ | |
| 332 u8 enc, /* Preferred text encoding */ | |
| 333 int createFlag /* Create new entry if true and does not otherwise exist */ | |
| 334 ){ | |
| 335 FuncDef *p; /* Iterator variable */ | |
| 336 FuncDef *pBest = 0; /* Best match found so far */ | |
| 337 int bestScore = 0; /* Score of best match */ | |
| 338 int h; /* Hash value */ | |
| 339 | |
| 340 | |
| 341 assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE ); | |
| 342 h = (sqlite3UpperToLower[(u8)zName[0]] + nName) % ArraySize(db->aFunc.a); | |
| 343 | |
| 344 /* First search for a match amongst the application-defined functions. | |
| 345 */ | |
| 346 p = functionSearch(&db->aFunc, h, zName, nName); | |
| 347 while( p ){ | |
| 348 int score = matchQuality(p, nArg, enc); | |
| 349 if( score>bestScore ){ | |
| 350 pBest = p; | |
| 351 bestScore = score; | |
| 352 } | |
| 353 p = p->pNext; | |
| 354 } | |
| 355 | |
| 356 /* If no match is found, search the built-in functions. | |
| 357 ** | |
| 358 ** Except, if createFlag is true, that means that we are trying to | |
| 359 ** install a new function. Whatever FuncDef structure is returned will | |
| 360 ** have fields overwritten with new information appropriate for the | |
| 361 ** new function. But the FuncDefs for built-in functions are read-only. | |
| 362 ** So we must not search for built-ins when creating a new function. | |
| 363 */ | |
| 364 if( !createFlag && !pBest ){ | |
| 365 FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions); | |
| 366 p = functionSearch(pHash, h, zName, nName); | |
| 367 while( p ){ | |
| 368 int score = matchQuality(p, nArg, enc); | |
| 369 if( score>bestScore ){ | |
| 370 pBest = p; | |
| 371 bestScore = score; | |
| 372 } | |
| 373 p = p->pNext; | |
| 374 } | |
| 375 } | |
| 376 | |
| 377 /* If the createFlag parameter is true and the search did not reveal an | |
| 378 ** exact match for the name, number of arguments and encoding, then add a | |
| 379 ** new entry to the hash table and return it. | |
| 380 */ | |
| 381 if( createFlag && (bestScore<6 || pBest->nArg!=nArg) && | |
| 382 (pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){ | |
| 383 pBest->zName = (char *)&pBest[1]; | |
| 384 pBest->nArg = (u16)nArg; | |
| 385 pBest->iPrefEnc = enc; | |
| 386 memcpy(pBest->zName, zName, nName); | |
| 387 pBest->zName[nName] = 0; | |
| 388 sqlite3FuncDefInsert(&db->aFunc, pBest); | |
| 389 } | |
| 390 | |
| 391 if( pBest && (pBest->xStep || pBest->xFunc || createFlag) ){ | |
| 392 return pBest; | |
| 393 } | |
| 394 return 0; | |
| 395 } | |
| 396 | |
| 397 /* | |
| 398 ** Free all resources held by the schema structure. The void* argument points | |
| 399 ** at a Schema struct. This function does not call sqlite3DbFree(db, ) on the | |
| 400 ** pointer itself, it just cleans up subsiduary resources (i.e. the contents | |
| 401 ** of the schema hash tables). | |
| 402 ** | |
| 403 ** The Schema.cache_size variable is not cleared. | |
| 404 */ | |
| 405 void sqlite3SchemaFree(void *p){ | |
| 406 Hash temp1; | |
| 407 Hash temp2; | |
| 408 HashElem *pElem; | |
| 409 Schema *pSchema = (Schema *)p; | |
| 410 | |
| 411 temp1 = pSchema->tblHash; | |
| 412 temp2 = pSchema->trigHash; | |
| 413 sqlite3HashInit(&pSchema->trigHash); | |
| 414 sqlite3HashClear(&pSchema->idxHash); | |
| 415 for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){ | |
| 416 sqlite3DeleteTrigger(0, (Trigger*)sqliteHashData(pElem)); | |
| 417 } | |
| 418 sqlite3HashClear(&temp2); | |
| 419 sqlite3HashInit(&pSchema->tblHash); | |
| 420 for(pElem=sqliteHashFirst(&temp1); pElem; pElem=sqliteHashNext(pElem)){ | |
| 421 Table *pTab = sqliteHashData(pElem); | |
| 422 assert( pTab->dbMem==0 ); | |
| 423 sqlite3DeleteTable(pTab); | |
| 424 } | |
| 425 sqlite3HashClear(&temp1); | |
| 426 pSchema->pSeqTab = 0; | |
| 427 pSchema->flags &= ~DB_SchemaLoaded; | |
| 428 } | |
| 429 | |
| 430 /* | |
| 431 ** Find and return the schema associated with a BTree. Create | |
| 432 ** a new one if necessary. | |
| 433 */ | |
| 434 Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){ | |
| 435 Schema * p; | |
| 436 if( pBt ){ | |
| 437 p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaFree); | |
| 438 }else{ | |
| 439 p = (Schema *)sqlite3MallocZero(sizeof(Schema)); | |
| 440 } | |
| 441 if( !p ){ | |
| 442 db->mallocFailed = 1; | |
| 443 }else if ( 0==p->file_format ){ | |
| 444 sqlite3HashInit(&p->tblHash); | |
| 445 sqlite3HashInit(&p->idxHash); | |
| 446 sqlite3HashInit(&p->trigHash); | |
| 447 p->enc = SQLITE_UTF8; | |
| 448 } | |
| 449 return p; | |
| 450 } | |
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Chromium Code Reviews
Issue 3108030:
Move bundled copy of sqlite one level deeper to better separate it... (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src/