--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/webengine/webkitutils/SqliteSymbian/vtab.c	Mon Mar 30 12:54:55 2009 +0300
@@ -0,0 +1,676 @@
+/*
+** 2006 June 10
+**
+** 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 code used to help implement virtual tables.
+**
+** $Id: vtab.c,v 1.31 2006/09/02 20:57:52 drh Exp $
+*/
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+#include "sqliteInt.h"
+
+/*
+** External API function used to create a new virtual-table module.
+*/
+int sqlite3_create_module(
+  sqlite3 *db,                    /* Database in which module is registered */
+  const char *zName,              /* Name assigned to this module */
+  const sqlite3_module *pModule,  /* The definition of the module */
+  void *pAux                      /* Context pointer for xCreate/xConnect */
+){
+  int nName = strlen(zName);
+  Module *pMod = (Module *)sqliteMallocRaw(sizeof(Module) + nName + 1);
+  if( pMod ){
+    char *zCopy = (char *)(&pMod[1]);
+    strcpy(zCopy, zName);
+    pMod->zName = zCopy;
+    pMod->pModule = pModule;
+    pMod->pAux = pAux;
+    pMod = (Module *)sqlite3HashInsert(&db->aModule, zCopy, nName, (void*)pMod);
+    sqliteFree(pMod);
+    sqlite3ResetInternalSchema(db, 0);
+  }
+  return sqlite3ApiExit(db, SQLITE_OK);
+}
+
+/*
+** Lock the virtual table so that it cannot be disconnected.
+** Locks nest.  Every lock should have a corresponding unlock.
+** If an unlock is omitted, resources leaks will occur.  
+**
+** If a disconnect is attempted while a virtual table is locked,
+** the disconnect is deferred until all locks have been removed.
+*/
+void sqlite3VtabLock(sqlite3_vtab *pVtab){
+  pVtab->nRef++;
+}
+
+/*
+** Unlock a virtual table.  When the last lock is removed,
+** disconnect the virtual table.
+*/
+void sqlite3VtabUnlock(sqlite3_vtab *pVtab){
+  pVtab->nRef--;
+  if( pVtab->nRef==0 ){
+    pVtab->pModule->xDisconnect(pVtab);
+  }
+}
+
+/*
+** Clear any and all virtual-table information from the Table record.
+** This routine is called, for example, just before deleting the Table
+** record.
+*/
+void sqlite3VtabClear(Table *p){
+  sqlite3_vtab *pVtab = p->pVtab;
+  if( pVtab ){
+    assert( p->pMod && p->pMod->pModule );
+    sqlite3VtabUnlock(pVtab);
+    p->pVtab = 0;
+  }
+  if( p->azModuleArg ){
+    int i;
+    for(i=0; i<p->nModuleArg; i++){
+      sqliteFree(p->azModuleArg[i]);
+    }
+    sqliteFree(p->azModuleArg);
+  }
+}
+
+/*
+** Add a new module argument to pTable->azModuleArg[].
+** The string is not copied - the pointer is stored.  The
+** string will be freed automatically when the table is
+** deleted.
+*/
+static void addModuleArgument(Table *pTable, char *zArg){
+  int i = pTable->nModuleArg++;
+  int nBytes = sizeof(char *)*(1+pTable->nModuleArg);
+  char **azModuleArg;
+  azModuleArg = sqliteRealloc(pTable->azModuleArg, nBytes);
+  if( azModuleArg==0 ){
+    int j;
+    for(j=0; j<i; j++){
+      sqliteFree(pTable->azModuleArg[j]);
+    }
+    sqliteFree(zArg);
+    sqliteFree(pTable->azModuleArg);
+    pTable->nModuleArg = 0;
+  }else{
+    azModuleArg[i] = zArg;
+    azModuleArg[i+1] = 0;
+  }
+  pTable->azModuleArg = azModuleArg;
+}
+
+/*
+** The parser calls this routine when it first sees a CREATE VIRTUAL TABLE
+** statement.  The module name has been parsed, but the optional list
+** of parameters that follow the module name are still pending.
+*/
+void sqlite3VtabBeginParse(
+  Parse *pParse,        /* Parsing context */
+  Token *pName1,        /* Name of new table, or database name */
+  Token *pName2,        /* Name of new table or NULL */
+  Token *pModuleName    /* Name of the module for the virtual table */
+){
+  int iDb;              /* The database the table is being created in */
+  Table *pTable;        /* The new virtual table */
+
+  sqlite3StartTable(pParse, pName1, pName2, 0, 0, 1, 0);
+  pTable = pParse->pNewTable;
+  if( pTable==0 || pParse->nErr ) return;
+  assert( 0==pTable->pIndex );
+
+  iDb = sqlite3SchemaToIndex(pParse->db, pTable->pSchema);
+  assert( iDb>=0 );
+
+  pTable->isVirtual = 1;
+  pTable->nModuleArg = 0;
+  addModuleArgument(pTable, sqlite3NameFromToken(pModuleName));
+  addModuleArgument(pTable, sqlite3StrDup(pParse->db->aDb[iDb].zName));
+  addModuleArgument(pTable, sqlite3StrDup(pTable->zName));
+  pParse->sNameToken.n = pModuleName->z + pModuleName->n - pName1->z;
+
+#ifndef SQLITE_OMIT_AUTHORIZATION
+  /* Creating a virtual table invokes the authorization callback twice.
+  ** The first invocation, to obtain permission to INSERT a row into the
+  ** sqlite_master table, has already been made by sqlite3StartTable().
+  ** The second call, to obtain permission to create the table, is made now.
+  */
+  if( pTable->azModuleArg ){
+    sqlite3AuthCheck(pParse, SQLITE_CREATE_VTABLE, pTable->zName, 
+            pTable->azModuleArg[0], pParse->db->aDb[iDb].zName);
+  }
+#endif
+}
+
+/*
+** This routine takes the module argument that has been accumulating
+** in pParse->zArg[] and appends it to the list of arguments on the
+** virtual table currently under construction in pParse->pTable.
+*/
+static void addArgumentToVtab(Parse *pParse){
+  if( pParse->sArg.z && pParse->pNewTable ){
+    const char *z = (const char*)pParse->sArg.z;
+    int n = pParse->sArg.n;
+    addModuleArgument(pParse->pNewTable, sqliteStrNDup(z, n));
+  }
+}
+
+/*
+** The parser calls this routine after the CREATE VIRTUAL TABLE statement
+** has been completely parsed.
+*/
+void sqlite3VtabFinishParse(Parse *pParse, Token *pEnd){
+  Table *pTab;        /* The table being constructed */
+  sqlite3 *db;        /* The database connection */
+  char *zModule;      /* The module name of the table: USING modulename */
+  Module *pMod = 0;
+
+  addArgumentToVtab(pParse);
+  pParse->sArg.z = 0;
+
+  /* Lookup the module name. */
+  pTab = pParse->pNewTable;
+  if( pTab==0 ) return;
+  db = pParse->db;
+  if( pTab->nModuleArg<1 ) return;
+  zModule = pTab->azModuleArg[0];
+  pMod = (Module *)sqlite3HashFind(&db->aModule, zModule, strlen(zModule));
+  pTab->pMod = pMod;
+  
+  /* If the CREATE VIRTUAL TABLE statement is being entered for the
+  ** first time (in other words if the virtual table is actually being
+  ** created now instead of just being read out of sqlite_master) then
+  ** do additional initialization work and store the statement text
+  ** in the sqlite_master table.
+  */
+  if( !db->init.busy ){
+    char *zStmt;
+    char *zWhere;
+    int iDb;
+    Vdbe *v;
+
+    /* Compute the complete text of the CREATE VIRTUAL TABLE statement */
+    if( pEnd ){
+      pParse->sNameToken.n = pEnd->z - pParse->sNameToken.z + pEnd->n;
+    }
+    zStmt = sqlite3MPrintf("CREATE VIRTUAL TABLE %T", &pParse->sNameToken);
+
+    /* A slot for the record has already been allocated in the 
+    ** SQLITE_MASTER table.  We just need to update that slot with all
+    ** the information we've collected.  
+    **
+    ** The top of the stack is the rootpage allocated by sqlite3StartTable().
+    ** This value is always 0 and is ignored, a virtual table does not have a
+    ** rootpage. The next entry on the stack is the rowid of the record
+    ** in the sqlite_master table.
+    */
+    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
+    sqlite3NestedParse(pParse,
+      "UPDATE %Q.%s "
+         "SET type='table', name=%Q, tbl_name=%Q, rootpage=0, sql=%Q "
+       "WHERE rowid=#1",
+      db->aDb[iDb].zName, SCHEMA_TABLE(iDb),
+      pTab->zName,
+      pTab->zName,
+      zStmt
+    );
+    sqliteFree(zStmt);
+    v = sqlite3GetVdbe(pParse);
+    sqlite3ChangeCookie(db, v, iDb);
+
+    sqlite3VdbeAddOp(v, OP_Expire, 0, 0);
+    zWhere = sqlite3MPrintf("name='%q'", pTab->zName);
+    sqlite3VdbeOp3(v, OP_ParseSchema, iDb, 0, zWhere, P3_DYNAMIC);
+    sqlite3VdbeOp3(v, OP_VCreate, iDb, 0, pTab->zName, strlen(pTab->zName) + 1);
+  }
+
+  /* If we are rereading the sqlite_master table create the in-memory
+  ** record of the table. If the module has already been registered,
+  ** also call the xConnect method here.
+  */
+  else {
+    Table *pOld;
+    Schema *pSchema = pTab->pSchema;
+    const char *zName = pTab->zName;
+    int nName = strlen(zName) + 1;
+    pOld = sqlite3HashInsert(&pSchema->tblHash, zName, nName, pTab);
+    if( pOld ){
+      assert( pTab==pOld );  /* Malloc must have failed inside HashInsert() */
+      return;
+    }
+    pParse->pNewTable = 0;
+  }
+}
+
+/*
+** The parser calls this routine when it sees the first token
+** of an argument to the module name in a CREATE VIRTUAL TABLE statement.
+*/
+void sqlite3VtabArgInit(Parse *pParse){
+  addArgumentToVtab(pParse);
+  pParse->sArg.z = 0;
+  pParse->sArg.n = 0;
+}
+
+/*
+** The parser calls this routine for each token after the first token
+** in an argument to the module name in a CREATE VIRTUAL TABLE statement.
+*/
+void sqlite3VtabArgExtend(Parse *pParse, Token *p){
+  Token *pArg = &pParse->sArg;
+  if( pArg->z==0 ){
+    pArg->z = p->z;
+    pArg->n = p->n;
+  }else{
+    assert(pArg->z < p->z);
+    pArg->n = (p->z + p->n - pArg->z);
+  }
+}
+
+/*
+** Invoke a virtual table constructor (either xCreate or xConnect). The
+** pointer to the function to invoke is passed as the fourth parameter
+** to this procedure.
+*/
+static int vtabCallConstructor(
+  sqlite3 *db, 
+  Table *pTab,
+  Module *pMod,
+  int (*xConstruct)(sqlite3*, void *, int, char **, sqlite3_vtab **),
+  char **pzErr
+){
+  int rc;
+  int rc2;
+  char **azArg = pTab->azModuleArg;
+  int nArg = pTab->nModuleArg;
+  char *zErr = sqlite3MPrintf("vtable constructor failed: %s", pTab->zName);
+
+  assert( !db->pVTab );
+  assert( xConstruct );
+
+  db->pVTab = pTab;
+  rc = sqlite3SafetyOff(db);
+  assert( rc==SQLITE_OK );
+  rc = xConstruct(db, pMod->pAux, nArg, azArg, &pTab->pVtab);
+  rc2 = sqlite3SafetyOn(db);
+  if( rc==SQLITE_OK && pTab->pVtab ){
+    pTab->pVtab->pModule = pMod->pModule;
+    pTab->pVtab->nRef = 1;
+  }
+
+  if( SQLITE_OK!=rc ){
+    *pzErr = zErr;
+    zErr = 0;
+  } else if( db->pVTab ){
+    const char *zFormat = "vtable constructor did not declare schema: %s";
+    *pzErr = sqlite3MPrintf(zFormat, pTab->zName);
+    rc = SQLITE_ERROR;
+  } 
+  if( rc==SQLITE_OK ){
+    rc = rc2;
+  }
+  db->pVTab = 0;
+  sqliteFree(zErr);
+  return rc;
+}
+
+/*
+** This function is invoked by the parser to call the xConnect() method
+** of the virtual table pTab. If an error occurs, an error code is returned 
+** and an error left in pParse.
+**
+** This call is a no-op if table pTab is not a virtual table.
+*/
+int sqlite3VtabCallConnect(Parse *pParse, Table *pTab){
+  Module *pMod;
+  const char *zModule;
+  int rc = SQLITE_OK;
+
+  if( !pTab || !pTab->isVirtual || pTab->pVtab ){
+    return SQLITE_OK;
+  }
+
+  pMod = pTab->pMod;
+  zModule = pTab->azModuleArg[0];
+  if( !pMod ){
+    const char *zModule = pTab->azModuleArg[0];
+    sqlite3ErrorMsg(pParse, "no such module: %s", zModule);
+    rc = SQLITE_ERROR;
+  } else {
+    char *zErr = 0;
+    sqlite3 *db = pParse->db;
+    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xConnect, &zErr);
+    if( rc!=SQLITE_OK ){
+      sqlite3ErrorMsg(pParse, "%s", zErr);
+    }
+    sqliteFree(zErr);
+  }
+
+  return rc;
+}
+
+/*
+** Add the virtual table pVtab to the array sqlite3.aVTrans[].
+*/
+static int addToVTrans(sqlite3 *db, sqlite3_vtab *pVtab){
+  const int ARRAY_INCR = 5;
+
+  /* Grow the sqlite3.aVTrans array if required */
+  if( (db->nVTrans%ARRAY_INCR)==0 ){
+    sqlite3_vtab **aVTrans;
+    int nBytes = sizeof(sqlite3_vtab *) * (db->nVTrans + ARRAY_INCR);
+    aVTrans = sqliteRealloc((void *)db->aVTrans, nBytes);
+    if( !aVTrans ){
+      return SQLITE_NOMEM;
+    }
+    memset(&aVTrans[db->nVTrans], 0, sizeof(sqlite3_vtab *)*ARRAY_INCR);
+    db->aVTrans = aVTrans;
+  }
+
+  /* Add pVtab to the end of sqlite3.aVTrans */
+  db->aVTrans[db->nVTrans++] = pVtab;
+  sqlite3VtabLock(pVtab);
+  return SQLITE_OK;
+}
+
+/*
+** This function is invoked by the vdbe to call the xCreate method
+** of the virtual table named zTab in database iDb. 
+**
+** If an error occurs, *pzErr is set to point an an English language
+** description of the error and an SQLITE_XXX error code is returned.
+** In this case the caller must call sqliteFree() on *pzErr.
+*/
+int sqlite3VtabCallCreate(sqlite3 *db, int iDb, const char *zTab, char **pzErr){
+  int rc = SQLITE_OK;
+  Table *pTab;
+  Module *pMod;
+  const char *zModule;
+
+  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);
+  assert(pTab && pTab->isVirtual && !pTab->pVtab);
+  pMod = pTab->pMod;
+  zModule = pTab->azModuleArg[0];
+
+  /* If the module has been registered and includes a Create method, 
+  ** invoke it now. If the module has not been registered, return an 
+  ** error. Otherwise, do nothing.
+  */
+  if( !pMod ){
+    *pzErr = sqlite3MPrintf("no such module: %s", zModule);
+    rc = SQLITE_ERROR;
+  }else{
+    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr);
+  }
+
+  if( rc==SQLITE_OK && pTab->pVtab ){
+      rc = addToVTrans(db, pTab->pVtab);
+  }
+
+  return rc;
+}
+
+/*
+** This function is used to set the schema of a virtual table.  It is only
+** valid to call this function from within the xCreate() or xConnect() of a
+** virtual table module.
+*/
+int sqlite3_declare_vtab(sqlite3 *db, const char *zCreateTable){
+  Parse sParse;
+
+  int rc = SQLITE_OK;
+  Table *pTab = db->pVTab;
+  char *zErr = 0;
+
+  if( !pTab ){
+    sqlite3Error(db, SQLITE_MISUSE, 0);
+    return SQLITE_MISUSE;
+  }
+  assert(pTab->isVirtual && pTab->nCol==0 && pTab->aCol==0);
+
+  memset(&sParse, 0, sizeof(Parse));
+  sParse.declareVtab = 1;
+  sParse.db = db;
+
+  if( 
+      SQLITE_OK == sqlite3RunParser(&sParse, zCreateTable, &zErr) && 
+      sParse.pNewTable && 
+      !sParse.pNewTable->pSelect && 
+      !sParse.pNewTable->isVirtual 
+  ){
+    pTab->aCol = sParse.pNewTable->aCol;
+    pTab->nCol = sParse.pNewTable->nCol;
+    sParse.pNewTable->nCol = 0;
+    sParse.pNewTable->aCol = 0;
+  } else {
+    sqlite3Error(db, SQLITE_ERROR, zErr);
+    sqliteFree(zErr);
+    rc = SQLITE_ERROR;
+  }
+  sParse.declareVtab = 0;
+
+  sqlite3_finalize((sqlite3_stmt*)sParse.pVdbe);
+  sqlite3DeleteTable(0, sParse.pNewTable);
+  sParse.pNewTable = 0;
+  db->pVTab = 0;
+
+  return rc;
+}
+
+/*
+** This function is invoked by the vdbe to call the xDestroy method
+** of the virtual table named zTab in database iDb. This occurs
+** when a DROP TABLE is mentioned.
+**
+** This call is a no-op if zTab is not a virtual table.
+*/
+int sqlite3VtabCallDestroy(sqlite3 *db, int iDb, const char *zTab)
+{
+  int rc = SQLITE_OK;
+  Table *pTab;
+
+  pTab = sqlite3FindTable(db, zTab, db->aDb[iDb].zName);
+  assert(pTab);
+  if( pTab->pVtab ){
+    int (*xDestroy)(sqlite3_vtab *pVTab) = pTab->pMod->pModule->xDestroy;
+    rc = sqlite3SafetyOff(db);
+    assert( rc==SQLITE_OK );
+    if( xDestroy ){
+      rc = xDestroy(pTab->pVtab);
+    }
+    sqlite3SafetyOn(db);
+    if( rc==SQLITE_OK ){
+      pTab->pVtab = 0;
+    }
+  }
+
+  return rc;
+}
+
+/*
+** This function invokes either the xRollback or xCommit method
+** of each of the virtual tables in the sqlite3.aVTrans array. The method
+** called is identified by the second argument, "offset", which is
+** the offset of the method to call in the sqlite3_module structure.
+**
+** The array is cleared after invoking the callbacks. 
+*/
+static void callFinaliser(sqlite3 *db, int offset){
+  int i;
+  for(i=0; i<db->nVTrans && db->aVTrans[i]; i++){
+    sqlite3_vtab *pVtab = db->aVTrans[i];
+    int (*x)(sqlite3_vtab *);
+    x = *(int (**)(sqlite3_vtab *))((char *)pVtab->pModule + offset);
+    if( x ) x(pVtab);
+    sqlite3VtabUnlock(pVtab);
+  }
+  sqliteFree(db->aVTrans);
+  db->nVTrans = 0;
+  db->aVTrans = 0;
+}
+
+/*
+** If argument rc2 is not SQLITE_OK, then return it and do nothing. 
+** Otherwise, invoke the xSync method of all virtual tables in the 
+** sqlite3.aVTrans array. Return the error code for the first error 
+** that occurs, or SQLITE_OK if all xSync operations are successful.
+*/
+int sqlite3VtabSync(sqlite3 *db, int rc2){
+  int i;
+  int rc = SQLITE_OK;
+  int rcsafety;
+  sqlite3_vtab **aVTrans = db->aVTrans;
+  if( rc2!=SQLITE_OK ) return rc2;
+
+  rc = sqlite3SafetyOff(db);
+  db->aVTrans = 0;
+  for(i=0; rc==SQLITE_OK && i<db->nVTrans && aVTrans[i]; i++){
+    sqlite3_vtab *pVtab = aVTrans[i];
+    int (*x)(sqlite3_vtab *);
+    x = pVtab->pModule->xSync;
+    if( x ){
+      rc = x(pVtab);
+    }
+  }
+  db->aVTrans = aVTrans;
+  rcsafety = sqlite3SafetyOn(db);
+
+  if( rc==SQLITE_OK ){
+    rc = rcsafety;
+  }
+  return rc;
+}
+
+/*
+** Invoke the xRollback method of all virtual tables in the 
+** sqlite3.aVTrans array. Then clear the array itself.
+*/
+int sqlite3VtabRollback(sqlite3 *db){
+  callFinaliser(db, (int)(&((sqlite3_module *)0)->xRollback));
+  return SQLITE_OK;
+}
+
+/*
+** Invoke the xCommit method of all virtual tables in the 
+** sqlite3.aVTrans array. Then clear the array itself.
+*/
+int sqlite3VtabCommit(sqlite3 *db){
+  callFinaliser(db, (int)(&((sqlite3_module *)0)->xCommit));
+  return SQLITE_OK;
+}
+
+/*
+** If the virtual table pVtab supports the transaction interface
+** (xBegin/xRollback/xCommit and optionally xSync) and a transaction is
+** not currently open, invoke the xBegin method now.
+**
+** If the xBegin call is successful, place the sqlite3_vtab pointer
+** in the sqlite3.aVTrans array.
+*/
+int sqlite3VtabBegin(sqlite3 *db, sqlite3_vtab *pVtab){
+  int rc = SQLITE_OK;
+  const sqlite3_module *pModule;
+
+  /* Special case: If db->aVTrans is NULL and db->nVTrans is greater
+  ** than zero, then this function is being called from within a
+  ** virtual module xSync() callback. It is illegal to write to 
+  ** virtual module tables in this case, so return SQLITE_LOCKED.
+  */
+  if( 0==db->aVTrans && db->nVTrans>0 ){
+    return SQLITE_LOCKED;
+  }
+  if( !pVtab ){
+    return SQLITE_OK;
+  } 
+  pModule = pVtab->pModule;
+
+  if( pModule->xBegin ){
+    int i;
+
+
+    /* If pVtab is already in the aVTrans array, return early */
+    for(i=0; (i<db->nVTrans) && 0!=db->aVTrans[i]; i++){
+      if( db->aVTrans[i]==pVtab ){
+        return SQLITE_OK;
+      }
+    }
+
+    /* Invoke the xBegin method */
+    rc = pModule->xBegin(pVtab);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+
+    rc = addToVTrans(db, pVtab);
+  }
+  return rc;
+}
+
+/*
+** The first parameter (pDef) is a function implementation.  The
+** second parameter (pExpr) is the first argument to this function.
+** If pExpr is a column in a virtual table, then let the virtual
+** table implementation have an opportunity to overload the function.
+**
+** This routine is used to allow virtual table implementations to
+** overload MATCH, LIKE, GLOB, and REGEXP operators.
+**
+** Return either the pDef argument (indicating no change) or a 
+** new FuncDef structure that is marked as ephemeral using the
+** SQLITE_FUNC_EPHEM flag.
+*/
+FuncDef *sqlite3VtabOverloadFunction(
+  FuncDef *pDef,  /* Function to possibly overload */
+  int nArg,       /* Number of arguments to the function */
+  Expr *pExpr     /* First argument to the function */
+){
+  Table *pTab;
+  sqlite3_vtab *pVtab;
+  sqlite3_module *pMod;
+  void (*xFunc)(sqlite3_context*,int,sqlite3_value**);
+  void *pArg;
+  FuncDef *pNew;
+
+  /* Check to see the left operand is a column in a virtual table */
+  if( pExpr==0 ) return pDef;
+  if( pExpr->op!=TK_COLUMN ) return pDef;
+  pTab = pExpr->pTab;
+  if( pTab==0 ) return pDef;
+  if( !pTab->isVirtual ) return pDef;
+  pVtab = pTab->pVtab;
+  assert( pVtab!=0 );
+  assert( pVtab->pModule!=0 );
+  pMod = (sqlite3_module *)pVtab->pModule;
+  if( pMod->xFindFunction==0 ) return pDef;
+ 
+  /* Call the xFuncFunction method on the virtual table implementation
+  ** to see if the implementation wants to overload this function */
+  if( pMod->xFindFunction(pVtab, nArg, pDef->zName, &xFunc, &pArg)==0 ){
+    return pDef;
+  }
+
+  /* Create a new ephemeral function definition for the overloaded
+  ** function */
+  pNew = sqliteMalloc( sizeof(*pNew) + strlen(pDef->zName) );
+  if( pNew==0 ){
+    return pDef;
+  }
+  *pNew = *pDef;
+  strcpy(pNew->zName, pDef->zName);
+  pNew->xFunc = xFunc;
+  pNew->pUserData = pArg;
+  pNew->flags |= SQLITE_FUNC_EPHEM;
+  return pNew;
+}
+
+#endif /* SQLITE_OMIT_VIRTUALTABLE */