From 7bb481fda9ecb134804b49c2ce77ca28f7eea583 Mon Sep 17 00:00:00 2001 From: Hans-Christoph Steiner Date: Fri, 30 Mar 2012 20:42:12 -0400 Subject: Imported Upstream version 2.0.3 --- src/callback.c | 457 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 457 insertions(+) create mode 100644 src/callback.c (limited to 'src/callback.c') diff --git a/src/callback.c b/src/callback.c new file mode 100644 index 0000000..ce84908 --- /dev/null +++ b/src/callback.c @@ -0,0 +1,457 @@ +/* +** 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. +*/ + +#include "sqliteInt.h" + +/* +** Invoke the 'collation needed' callback to request a collation sequence +** in the encoding enc of name zName, length nName. +*/ +static void callCollNeeded(sqlite3 *db, int enc, const char *zName){ + assert( !db->xCollNeeded || !db->xCollNeeded16 ); + if( db->xCollNeeded ){ + char *zExternal = sqlite3DbStrDup(db, zName); + if( !zExternal ) return; + db->xCollNeeded(db->pCollNeededArg, db, enc, zExternal); + sqlite3DbFree(db, zExternal); + } +#ifndef SQLITE_OMIT_UTF16 + if( db->xCollNeeded16 ){ + char const *zExternal; + sqlite3_value *pTmp = sqlite3ValueNew(db); + sqlite3ValueSetStr(pTmp, -1, 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 i; + static const u8 aEnc[] = { SQLITE_UTF16BE, SQLITE_UTF16LE, SQLITE_UTF8 }; + for(i=0; i<3; i++){ + pColl2 = sqlite3FindCollSeq(db, aEnc[i], z, 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 desired 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. +** +** See also: sqlite3LocateCollSeq(), sqlite3FindCollSeq() +*/ +CollSeq *sqlite3GetCollSeq( + sqlite3* db, /* The database connection */ + u8 enc, /* The desired encoding for the collating sequence */ + CollSeq *pColl, /* Collating sequence with native encoding, or NULL */ + const char *zName /* Collating sequence name */ +){ + CollSeq *p; + + p = pColl; + if( !p ){ + p = sqlite3FindCollSeq(db, enc, zName, 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, enc, zName); + p = sqlite3FindCollSeq(db, enc, zName, 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; + sqlite3 *db = pParse->db; + CollSeq *p = sqlite3GetCollSeq(db, ENC(db), pColl, zName); + if( !p ){ + 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, /* Database connection */ + const char *zName, /* Name of the collating sequence */ + int create /* Create a new entry if true */ +){ + CollSeq *pColl; + int nName = sqlite3Strlen30(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 occurred 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. +** +** See also: sqlite3LocateCollSeq(), sqlite3GetCollSeq() +*/ +CollSeq *sqlite3FindCollSeq( + sqlite3 *db, + u8 enc, + const char *zName, + int create +){ + CollSeq *pColl; + if( zName ){ + pColl = findCollSeqEntry(db, zName, 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; +} + +/* During the search for the best function definition, this procedure +** is called to test how well the function passed as the first argument +** matches the request for a function with nArg arguments in a system +** that uses encoding enc. The value returned indicates how well the +** request is matched. A higher value indicates a better match. +** +** The returned value is always between 0 and 6, as follows: +** +** 0: Not a match, or if nArg<0 and the function is has no implementation. +** 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. +** +*/ +static int matchQuality(FuncDef *p, int nArg, u8 enc){ + int match = 0; + if( p->nArg==-1 || p->nArg==nArg + || (nArg==-1 && (p->xFunc!=0 || p->xStep!=0)) + ){ + match = 1; + 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; + } + } + return match; +} + +/* +** Search a FuncDefHash for a function with the given name. Return +** a pointer to the matching FuncDef if found, or 0 if there is no match. +*/ +static FuncDef *functionSearch( + FuncDefHash *pHash, /* Hash table to search */ + int h, /* Hash of the name */ + const char *zFunc, /* Name of function */ + int nFunc /* Number of bytes in zFunc */ +){ + FuncDef *p; + for(p=pHash->a[h]; p; p=p->pHash){ + if( sqlite3StrNICmp(p->zName, zFunc, nFunc)==0 && p->zName[nFunc]==0 ){ + return p; + } + } + return 0; +} + +/* +** Insert a new FuncDef into a FuncDefHash hash table. +*/ +void sqlite3FuncDefInsert( + FuncDefHash *pHash, /* The hash table into which to insert */ + FuncDef *pDef /* The function definition to insert */ +){ + FuncDef *pOther; + int nName = sqlite3Strlen30(pDef->zName); + u8 c1 = (u8)pDef->zName[0]; + int h = (sqlite3UpperToLower[c1] + nName) % ArraySize(pHash->a); + pOther = functionSearch(pHash, h, pDef->zName, nName); + if( pOther ){ + assert( pOther!=pDef && pOther->pNext!=pDef ); + pDef->pNext = pOther->pNext; + pOther->pNext = pDef; + }else{ + pDef->pNext = 0; + pDef->pHash = pHash->a[h]; + pHash->a[h] = pDef; + } +} + + + +/* +** 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 *pBest = 0; /* Best match found so far */ + int bestScore = 0; /* Score of best match */ + int h; /* Hash value */ + + + assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE ); + h = (sqlite3UpperToLower[(u8)zName[0]] + nName) % ArraySize(db->aFunc.a); + + /* First search for a match amongst the application-defined functions. + */ + p = functionSearch(&db->aFunc, h, zName, nName); + while( p ){ + int score = matchQuality(p, nArg, enc); + if( score>bestScore ){ + pBest = p; + bestScore = score; + } + p = p->pNext; + } + + /* If no match is found, search the built-in functions. + ** + ** If the SQLITE_PreferBuiltin flag is set, then search the built-in + ** functions even if a prior app-defined function was found. And give + ** priority to built-in functions. + ** + ** Except, if createFlag is true, that means that we are trying to + ** install a new function. Whatever FuncDef structure is returned it will + ** have fields overwritten with new information appropriate for the + ** new function. But the FuncDefs for built-in functions are read-only. + ** So we must not search for built-ins when creating a new function. + */ + if( !createFlag && (pBest==0 || (db->flags & SQLITE_PreferBuiltin)!=0) ){ + FuncDefHash *pHash = &GLOBAL(FuncDefHash, sqlite3GlobalFunctions); + bestScore = 0; + p = functionSearch(pHash, h, zName, nName); + while( p ){ + int score = matchQuality(p, nArg, enc); + if( score>bestScore ){ + pBest = p; + bestScore = score; + } + p = p->pNext; + } + } + + /* If the createFlag parameter is true and the search 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 && (bestScore<6 || pBest->nArg!=nArg) && + (pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){ + pBest->zName = (char *)&pBest[1]; + pBest->nArg = (u16)nArg; + pBest->iPrefEnc = enc; + memcpy(pBest->zName, zName, nName); + pBest->zName[nName] = 0; + sqlite3FuncDefInsert(&db->aFunc, pBest); + } + + 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 subsidiary resources (i.e. the contents +** of the schema hash tables). +** +** The Schema.cache_size variable is not cleared. +*/ +void sqlite3SchemaClear(void *p){ + Hash temp1; + Hash temp2; + HashElem *pElem; + Schema *pSchema = (Schema *)p; + + temp1 = pSchema->tblHash; + temp2 = pSchema->trigHash; + sqlite3HashInit(&pSchema->trigHash); + sqlite3HashClear(&pSchema->idxHash); + for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){ + sqlite3DeleteTrigger(0, (Trigger*)sqliteHashData(pElem)); + } + sqlite3HashClear(&temp2); + sqlite3HashInit(&pSchema->tblHash); + for(pElem=sqliteHashFirst(&temp1); pElem; pElem=sqliteHashNext(pElem)){ + Table *pTab = sqliteHashData(pElem); + sqlite3DeleteTable(0, pTab); + } + sqlite3HashClear(&temp1); + sqlite3HashClear(&pSchema->fkeyHash); + pSchema->pSeqTab = 0; + if( pSchema->flags & DB_SchemaLoaded ){ + pSchema->iGeneration++; + 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), sqlite3SchemaClear); + }else{ + p = (Schema *)sqlite3DbMallocZero(0, sizeof(Schema)); + } + if( !p ){ + db->mallocFailed = 1; + }else if ( 0==p->file_format ){ + sqlite3HashInit(&p->tblHash); + sqlite3HashInit(&p->idxHash); + sqlite3HashInit(&p->trigHash); + sqlite3HashInit(&p->fkeyHash); + p->enc = SQLITE_UTF8; + } + return p; +} -- cgit v1.2.3