--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/persistentstorage/sql/SQLite/callback.c Fri Jan 22 11:06:30 2010 +0200
@@ -0,0 +1,380 @@
+/*
+** 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;
+}