| /* |
| ** 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; |
| } |