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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 17:28:19 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-05 17:28:19 +0000
commit18657a960e125336f704ea058e25c27bd3900dcb (patch)
tree17b438b680ed45a996d7b59951e6aa34023783f2 /src/callback.c
parentInitial commit. (diff)
downloadsqlite3-18657a960e125336f704ea058e25c27bd3900dcb.tar.xz
sqlite3-18657a960e125336f704ea058e25c27bd3900dcb.zip
Adding upstream version 3.40.1.upstream/3.40.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/callback.c')
-rw-r--r--src/callback.c539
1 files changed, 539 insertions, 0 deletions
diff --git a/src/callback.c b/src/callback.c
new file mode 100644
index 0000000..6cbe8e5
--- /dev/null
+++ b/src/callback.c
@@ -0,0 +1,539 @@
+/*
+** 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 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 && pColl->xCmp==0 ){
+ const char *zName = pColl->zName;
+ sqlite3 *db = pParse->db;
+ CollSeq *p = sqlite3GetCollSeq(pParse, ENC(db), pColl, zName);
+ if( !p ){
+ 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
+** preferred 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;
+ pColl = sqlite3HashFind(&db->aCollSeq, zName);
+
+ if( 0==pColl && create ){
+ int nName = sqlite3Strlen30(zName) + 1;
+ pColl = sqlite3DbMallocZero(db, 3*sizeof(*pColl) + nName);
+ 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);
+ pDel = sqlite3HashInsert(&db->aCollSeq, pColl[0].zName, 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 ){
+ sqlite3OomFault(db);
+ 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, /* Database connection to search */
+ u8 enc, /* Desired text encoding */
+ const char *zName, /* Name of the collating sequence. Might be NULL */
+ int create /* True to create CollSeq if doesn't already exist */
+){
+ CollSeq *pColl;
+ assert( SQLITE_UTF8==1 && SQLITE_UTF16LE==2 && SQLITE_UTF16BE==3 );
+ assert( enc>=SQLITE_UTF8 && enc<=SQLITE_UTF16BE );
+ if( zName ){
+ pColl = findCollSeqEntry(db, zName, create);
+ if( pColl ) pColl += enc-1;
+ }else{
+ pColl = db->pDfltColl;
+ }
+ return pColl;
+}
+
+/*
+** Change the text encoding for a database connection. This means that
+** the pDfltColl must change as well.
+*/
+void sqlite3SetTextEncoding(sqlite3 *db, u8 enc){
+ assert( enc==SQLITE_UTF8 || enc==SQLITE_UTF16LE || enc==SQLITE_UTF16BE );
+ db->enc = enc;
+ /* EVIDENCE-OF: R-08308-17224 The default collating function for all
+ ** strings is BINARY.
+ */
+ db->pDfltColl = sqlite3FindCollSeq(db, enc, sqlite3StrBINARY, 0);
+}
+
+/*
+** 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. If no collation is found, leave an error message.
+**
+** See also: sqlite3LocateCollSeq(), sqlite3FindCollSeq()
+*/
+CollSeq *sqlite3GetCollSeq(
+ Parse *pParse, /* Parsing context */
+ 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;
+ sqlite3 *db = pParse->db;
+
+ 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 );
+ if( p==0 ){
+ sqlite3ErrorMsg(pParse, "no such collation sequence: %s", zName);
+ pParse->rc = SQLITE_ERROR_MISSING_COLLSEQ;
+ }
+ return p;
+}
+
+/*
+** This function returns the collation sequence for database native text
+** encoding identified by the string zName.
+**
+** If the requested collation sequence is not available, or not available
+** in the database native encoding, the collation factory is invoked to
+** request it. If the collation factory does not supply such a sequence,
+** and the sequence is available in another text encoding, then that is
+** returned instead.
+**
+** If no versions of the requested collations sequence are available, or
+** another error occurs, NULL is returned and an error message written into
+** pParse.
+**
+** This routine is a wrapper around sqlite3FindCollSeq(). This routine
+** invokes the collation factory if the named collation cannot be found
+** and generates an error message.
+**
+** See also: sqlite3FindCollSeq(), sqlite3GetCollSeq()
+*/
+CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char *zName){
+ sqlite3 *db = pParse->db;
+ u8 enc = ENC(db);
+ u8 initbusy = db->init.busy;
+ CollSeq *pColl;
+
+ pColl = sqlite3FindCollSeq(db, enc, zName, initbusy);
+ if( !initbusy && (!pColl || !pColl->xCmp) ){
+ pColl = sqlite3GetCollSeq(pParse, enc, pColl, zName);
+ }
+
+ 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.
+**
+** If nArg is -1 that means to only return a match (non-zero) if p->nArg
+** is also -1. In other words, we are searching for a function that
+** takes a variable number of arguments.
+**
+** If nArg is -2 that means that we are searching for any function
+** regardless of the number of arguments it uses, so return a positive
+** match score for any
+**
+** The returned value is always between 0 and 6, as follows:
+**
+** 0: Not a match.
+** 1: UTF8/16 conversion required and function takes any number of arguments.
+** 2: UTF16 byte order change required and function takes any number of args.
+** 3: encoding matches and function takes any number of arguments
+** 4: UTF8/16 conversion required - argument count matches exactly
+** 5: UTF16 byte order conversion required - argument count matches exactly
+** 6: Perfect match: encoding and argument count match exactly.
+**
+** If nArg==(-2) then any function with a non-null xSFunc is
+** a perfect match and any function with xSFunc NULL is
+** a non-match.
+*/
+#define FUNC_PERFECT_MATCH 6 /* The score for a perfect match */
+static int matchQuality(
+ FuncDef *p, /* The function we are evaluating for match quality */
+ int nArg, /* Desired number of arguments. (-1)==any */
+ u8 enc /* Desired text encoding */
+){
+ int match;
+ assert( p->nArg>=-1 );
+
+ /* Wrong number of arguments means "no match" */
+ if( p->nArg!=nArg ){
+ if( nArg==(-2) ) return (p->xSFunc==0) ? 0 : FUNC_PERFECT_MATCH;
+ if( p->nArg>=0 ) return 0;
+ }
+
+ /* Give a better score to a function with a specific number of arguments
+ ** than to function that accepts any number of arguments. */
+ if( p->nArg==nArg ){
+ match = 4;
+ }else{
+ match = 1;
+ }
+
+ /* Bonus points if the text encoding matches */
+ if( enc==(p->funcFlags & SQLITE_FUNC_ENCMASK) ){
+ match += 2; /* Exact encoding match */
+ }else if( (enc & p->funcFlags & 2)!=0 ){
+ match += 1; /* Both are UTF16, but with different byte orders */
+ }
+
+ 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.
+*/
+FuncDef *sqlite3FunctionSearch(
+ int h, /* Hash of the name */
+ const char *zFunc /* Name of function */
+){
+ FuncDef *p;
+ for(p=sqlite3BuiltinFunctions.a[h]; p; p=p->u.pHash){
+ assert( p->funcFlags & SQLITE_FUNC_BUILTIN );
+ if( sqlite3StrICmp(p->zName, zFunc)==0 ){
+ return p;
+ }
+ }
+ return 0;
+}
+
+/*
+** Insert a new FuncDef into a FuncDefHash hash table.
+*/
+void sqlite3InsertBuiltinFuncs(
+ FuncDef *aDef, /* List of global functions to be inserted */
+ int nDef /* Length of the apDef[] list */
+){
+ int i;
+ for(i=0; i<nDef; i++){
+ FuncDef *pOther;
+ const char *zName = aDef[i].zName;
+ int nName = sqlite3Strlen30(zName);
+ int h = SQLITE_FUNC_HASH(zName[0], nName);
+ assert( aDef[i].funcFlags & SQLITE_FUNC_BUILTIN );
+ pOther = sqlite3FunctionSearch(h, zName);
+ if( pOther ){
+ assert( pOther!=&aDef[i] && pOther->pNext!=&aDef[i] );
+ aDef[i].pNext = pOther->pNext;
+ pOther->pNext = &aDef[i];
+ }else{
+ aDef[i].pNext = 0;
+ aDef[i].u.pHash = sqlite3BuiltinFunctions.a[h];
+ sqlite3BuiltinFunctions.a[h] = &aDef[i];
+ }
+ }
+}
+
+
+
+/*
+** 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.
+**
+** If nArg is -2, then the first valid function found is returned. A
+** function is valid if xSFunc is non-zero. The nArg==(-2)
+** case is used to see if zName is a valid function name for some number
+** of arguments. If nArg is -2, then createFlag must be 0.
+**
+** 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. zero-terminated */
+ int nArg, /* Number of arguments. -1 means any number */
+ u8 enc, /* Preferred text encoding */
+ u8 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 */
+ int nName; /* Length of the name */
+
+ assert( nArg>=(-2) );
+ assert( nArg>=(-1) || createFlag==0 );
+ nName = sqlite3Strlen30(zName);
+
+ /* First search for a match amongst the application-defined functions.
+ */
+ p = (FuncDef*)sqlite3HashFind(&db->aFunc, zName);
+ 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 DBFLAG_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->mDbFlags & DBFLAG_PreferBuiltin)!=0) ){
+ bestScore = 0;
+ h = SQLITE_FUNC_HASH(sqlite3UpperToLower[(u8)zName[0]], nName);
+ p = sqlite3FunctionSearch(h, zName);
+ 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<FUNC_PERFECT_MATCH &&
+ (pBest = sqlite3DbMallocZero(db, sizeof(*pBest)+nName+1))!=0 ){
+ FuncDef *pOther;
+ u8 *z;
+ pBest->zName = (const char*)&pBest[1];
+ pBest->nArg = (u16)nArg;
+ pBest->funcFlags = enc;
+ memcpy((char*)&pBest[1], zName, nName+1);
+ for(z=(u8*)pBest->zName; *z; z++) *z = sqlite3UpperToLower[*z];
+ pOther = (FuncDef*)sqlite3HashInsert(&db->aFunc, pBest->zName, pBest);
+ if( pOther==pBest ){
+ sqlite3DbFree(db, pBest);
+ sqlite3OomFault(db);
+ return 0;
+ }else{
+ pBest->pNext = pOther;
+ }
+ }
+
+ if( pBest && (pBest->xSFunc || 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;
+ sqlite3 xdb;
+
+ memset(&xdb, 0, sizeof(xdb));
+ temp1 = pSchema->tblHash;
+ temp2 = pSchema->trigHash;
+ sqlite3HashInit(&pSchema->trigHash);
+ sqlite3HashClear(&pSchema->idxHash);
+ for(pElem=sqliteHashFirst(&temp2); pElem; pElem=sqliteHashNext(pElem)){
+ sqlite3DeleteTrigger(&xdb, (Trigger*)sqliteHashData(pElem));
+ }
+ sqlite3HashClear(&temp2);
+ sqlite3HashInit(&pSchema->tblHash);
+ for(pElem=sqliteHashFirst(&temp1); pElem; pElem=sqliteHashNext(pElem)){
+ Table *pTab = sqliteHashData(pElem);
+ sqlite3DeleteTable(&xdb, pTab);
+ }
+ sqlite3HashClear(&temp1);
+ sqlite3HashClear(&pSchema->fkeyHash);
+ pSchema->pSeqTab = 0;
+ if( pSchema->schemaFlags & DB_SchemaLoaded ){
+ pSchema->iGeneration++;
+ }
+ pSchema->schemaFlags &= ~(DB_SchemaLoaded|DB_ResetWanted);
+}
+
+/*
+** 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 ){
+ sqlite3OomFault(db);
+ }else if ( 0==p->file_format ){
+ sqlite3HashInit(&p->tblHash);
+ sqlite3HashInit(&p->idxHash);
+ sqlite3HashInit(&p->trigHash);
+ sqlite3HashInit(&p->fkeyHash);
+ p->enc = SQLITE_UTF8;
+ }
+ return p;
+}