Imported Upstream version 2.0.3

1 files changed, 457 insertions, 0 deletions

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;
+}