/*** 2005 May 23 **** The author disclaims copyright to this source code. In place of** a legal notice, here is a blessing:**** May you do good and not evil.** May you find forgiveness for yourself and forgive others.** May you share freely, never taking more than you give.******************************************************************************* This file contains functions used to access the internal hash tables** of user defined functions and collation sequences.**** $Id: callback.c,v 1.26 2008/07/28 19:34:53 drh Exp $*/#include "sqliteInt.h"/*** Invoke the 'collation needed' callback to request a collation sequence** in the database text encoding of name zName, length nName.** If the collation sequence*/static void callCollNeeded(sqlite3 *db, const char *zName, int nName){ assert( !db->xCollNeeded || !db->xCollNeeded16 ); if( nName<0 ) nName = sqlite3Strlen(db, zName); if( db->xCollNeeded ){ char *zExternal = sqlite3DbStrNDup(db, zName, nName); if( !zExternal ) return; db->xCollNeeded(db->pCollNeededArg, db, (int)ENC(db), zExternal); sqlite3DbFree(db, zExternal); }#ifndef SQLITE_OMIT_UTF16 if( db->xCollNeeded16 ){ char const *zExternal; sqlite3_value *pTmp = sqlite3ValueNew(db); sqlite3ValueSetStr(pTmp, nName, zName, SQLITE_UTF8, SQLITE_STATIC); zExternal = sqlite3ValueText(pTmp, SQLITE_UTF16NATIVE); if( zExternal ){ db->xCollNeeded16(db->pCollNeededArg, db, (int)ENC(db), zExternal); } sqlite3ValueFree(pTmp); }#endif}/*** This routine is called if the collation factory fails to deliver a** collation function in the best encoding but there may be other versions** of this collation function (for other text encodings) available. Use one** of these instead if they exist. Avoid a UTF-8 <-> UTF-16 conversion if** possible.*/static int synthCollSeq(sqlite3 *db, CollSeq *pColl){ CollSeq *pColl2; char *z = pColl->zName; int n = strlen(z); int i; static const u8 aEnc[] = { SQLITE_UTF16BE, SQLITE_UTF16LE, SQLITE_UTF8 }; for(i=0; i<3; i++){ pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, n, 0); if( pColl2->xCmp!=0 ){ memcpy(pColl, pColl2, sizeof(CollSeq)); pColl->xDel = 0; /* Do not copy the destructor */ return SQLITE_OK; } } return SQLITE_ERROR;}/*** This function is responsible for invoking the collation factory callback** or substituting a collation sequence of a different encoding when the** requested collation sequence is not available in the database native** encoding.** ** If it is not NULL, then pColl must point to the database native encoding ** collation sequence with name zName, length nName.**** The return value is either the collation sequence to be used in database** db for collation type name zName, length nName, or NULL, if no collation** sequence can be found.*/CollSeq *sqlite3GetCollSeq( sqlite3* db, CollSeq *pColl, const char *zName, int nName){ CollSeq *p; p = pColl; if( !p ){ p = sqlite3FindCollSeq(db, ENC(db), zName, nName, 0); } if( !p || !p->xCmp ){ /* No collation sequence of this type for this encoding is registered. ** Call the collation factory to see if it can supply us with one. */ callCollNeeded(db, zName, nName); p = sqlite3FindCollSeq(db, ENC(db), zName, nName, 0); } if( p && !p->xCmp && synthCollSeq(db, p) ){ p = 0; } assert( !p || p->xCmp ); return p;}/*** This routine is called on a collation sequence before it is used to** check that it is defined. An undefined collation sequence exists when** a database is loaded that contains references to collation sequences** that have not been defined by sqlite3_create_collation() etc.**** If required, this routine calls the 'collation needed' callback to** request a definition of the collating sequence. If this doesn't work, ** an equivalent collating sequence that uses a text encoding different** from the main database is substituted, if one is available.*/int sqlite3CheckCollSeq(Parse *pParse, CollSeq *pColl){ if( pColl ){ const char *zName = pColl->zName; CollSeq *p = sqlite3GetCollSeq(pParse->db, pColl, zName, -1); if( !p ){ if( pParse->nErr==0 ){ sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName); } pParse->nErr++; return SQLITE_ERROR; } assert( p==pColl ); } return SQLITE_OK;}/*** Locate and return an entry from the db.aCollSeq hash table. If the entry** specified by zName and nName is not found and parameter 'create' is** true, then create a new entry. Otherwise return NULL.**** Each pointer stored in the sqlite3.aCollSeq hash table contains an** array of three CollSeq structures. The first is the collation sequence** prefferred for UTF-8, the second UTF-16le, and the third UTF-16be.**** Stored immediately after the three collation sequences is a copy of** the collation sequence name. A pointer to this string is stored in** each collation sequence structure.*/static CollSeq *findCollSeqEntry( sqlite3 *db, const char *zName, int nName, int create){ CollSeq *pColl; if( nName<0 ) nName = sqlite3Strlen(db, zName); pColl = sqlite3HashFind(&db->aCollSeq, zName, nName); if( 0==pColl && create ){ pColl = sqlite3DbMallocZero(db, 3*sizeof(*pColl) + nName + 1 ); if( pColl ){ CollSeq *pDel = 0; pColl[0].zName = (char*)&pColl[3]; pColl[0].enc = SQLITE_UTF8; pColl[1].zName = (char*)&pColl[3]; pColl[1].enc = SQLITE_UTF16LE; pColl[2].zName = (char*)&pColl[3]; pColl[2].enc = SQLITE_UTF16BE; memcpy(pColl[0].zName, zName, nName); pColl[0].zName[nName] = 0; pDel = sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, nName, pColl); /* If a malloc() failure occured in sqlite3HashInsert(), it will ** return the pColl pointer to be deleted (because it wasn't added ** to the hash table). */ assert( pDel==0 || pDel==pColl ); if( pDel!=0 ){ db->mallocFailed = 1; sqlite3DbFree(db, pDel); pColl = 0; } } } return pColl;}/*** Parameter zName points to a UTF-8 encoded string nName bytes long.** Return the CollSeq* pointer for the collation sequence named zName** for the encoding 'enc' from the database 'db'.**** If the entry specified is not found and 'create' is true, then create a** new entry. Otherwise return NULL.**** A separate function sqlite3LocateCollSeq() is a wrapper around** this routine. sqlite3LocateCollSeq() invokes the collation factory** if necessary and generates an error message if the collating sequence** cannot be found.*/CollSeq *sqlite3FindCollSeq( sqlite3 *db, u8 enc, const char *zName, int nName, int create){ CollSeq *pColl; if( zName ){ pColl = findCollSeqEntry(db, zName, nName, create); }else{ pColl = db->pDfltColl; } assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 ); assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE ); if( pColl ) pColl += enc-1; return pColl;}/*** Locate a user function given a name, a number of arguments and a flag** indicating whether the function prefers UTF-16 over UTF-8. Return a** pointer to the FuncDef structure that defines that function, or return** NULL if the function does not exist.**** If the createFlag argument is true, then a new (blank) FuncDef** structure is created and liked into the "db" structure if a** no matching function previously existed. When createFlag is true** and the nArg parameter is -1, then only a function that accepts** any number of arguments will be returned.**** If createFlag is false and nArg is -1, then the first valid** function found is returned. A function is valid if either xFunc** or xStep is non-zero.**** If createFlag is false, then a function with the required name and** number of arguments may be returned even if the eTextRep flag does not** match that requested.*/FuncDef *sqlite3FindFunction( sqlite3 *db, /* An open database */ const char *zName, /* Name of the function. Not null-terminated */ int nName, /* Number of characters in the name */ int nArg, /* Number of arguments. -1 means any number */ u8 enc, /* Preferred text encoding */ int createFlag /* Create new entry if true and does not otherwise exist */){ FuncDef *p; /* Iterator variable */ FuncDef *pFirst; /* First function with this name */ FuncDef *pBest = 0; /* Best match found so far */ int bestmatch = 0; assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE ); if( nArg<-1 ) nArg = -1; pFirst = (FuncDef*)sqlite3HashFind(&db->aFunc, zName, nName); for(p=pFirst; p; p=p->pNext){ /* During the search for the best function definition, bestmatch is set ** as follows to indicate the quality of the match with the definition ** pointed to by pBest: ** ** 0: pBest is NULL. No match has been found. ** 1: A variable arguments function that prefers UTF-8 when a UTF-16 ** encoding is requested, or vice versa. ** 2: A variable arguments function that uses UTF-16BE when UTF-16LE is ** requested, or vice versa. ** 3: A variable arguments function using the same text encoding. ** 4: A function with the exact number of arguments requested that ** prefers UTF-8 when a UTF-16 encoding is requested, or vice versa. ** 5: A function with the exact number of arguments requested that ** prefers UTF-16LE when UTF-16BE is requested, or vice versa. ** 6: An exact match. ** ** A larger value of 'matchqual' indicates a more desirable match. */ if( p->nArg==-1 || p->nArg==nArg || nArg==-1 ){ int match = 1; /* Quality of this match */ if( p->nArg==nArg || nArg==-1 ){ match = 4; } if( enc==p->iPrefEnc ){ match += 2; } else if( (enc==SQLITE_UTF16LE && p->iPrefEnc==SQLITE_UTF16BE) || (enc==SQLITE_UTF16BE && p->iPrefEnc==SQLITE_UTF16LE) ){ match += 1; } if( match>bestmatch ){ pBest = p; bestmatch = match; } } } /* If the createFlag parameter is true, and the seach did not reveal an ** exact match for the name, number of arguments and encoding, then add a ** new entry to the hash table and return it. */ if( createFlag && bestmatch<6 && (pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName))!=0 ){ pBest->nArg = nArg; pBest->pNext = pFirst; pBest->iPrefEnc = enc; memcpy(pBest->zName, zName, nName); pBest->zName[nName] = 0; if( pBest==sqlite3HashInsert(&db->aFunc,pBest->zName,nName,(void*)pBest) ){ db->mallocFailed = 1; sqlite3DbFree(db, pBest); return 0; } } if( pBest && (pBest->xStep || pBest->xFunc || createFlag) ){ return pBest; } return 0;}/*** Free all resources held by the schema structure. The void* argument points** at a Schema struct. This function does not call sqlite3DbFree(db, ) on the ** pointer itself, it just cleans up subsiduary resources (i.e. the contents** of the schema hash tables).**** The Schema.cache_size variable is not cleared.*/void sqlite3SchemaFree(void *p){ Hash temp1; Hash temp2; HashElem *pElem; Schema *pSchema = (Schema *)p; temp1 = pSchema->tblHash; temp2 = pSchema->trigHash; sqlite3HashInit(&pSchema->trigHash, SQLITE_HASH_STRING, 0); sqlite3HashClear(&pSchema->aFKey); sqlite3HashClear(&pSchema->idxHash); for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){ sqlite3DeleteTrigger(0, (Trigger*)sqliteHashData(pElem)); } sqlite3HashClear(&temp2); sqlite3HashInit(&pSchema->tblHash, SQLITE_HASH_STRING, 0); for(pElem=sqliteHashFirst(&temp1); pElem; pElem=sqliteHashNext(pElem)){ Table *pTab = sqliteHashData(pElem); sqlite3DeleteTable(pTab); } sqlite3HashClear(&temp1); pSchema->pSeqTab = 0; pSchema->flags &= ~DB_SchemaLoaded;}/*** Find and return the schema associated with a BTree. Create** a new one if necessary.*/Schema *sqlite3SchemaGet(sqlite3 *db, Btree *pBt){ Schema * p; if( pBt ){ p = (Schema *)sqlite3BtreeSchema(pBt, sizeof(Schema), sqlite3SchemaFree); }else{ p = (Schema *)sqlite3MallocZero(sizeof(Schema)); } if( !p ){ db->mallocFailed = 1; }else if ( 0==p->file_format ){ sqlite3HashInit(&p->tblHash, SQLITE_HASH_STRING, 0); sqlite3HashInit(&p->idxHash, SQLITE_HASH_STRING, 0); sqlite3HashInit(&p->trigHash, SQLITE_HASH_STRING, 0); sqlite3HashInit(&p->aFKey, SQLITE_HASH_STRING, 1); p->enc = SQLITE_UTF8; } return p;}