engine/sqlite/src/prepare.cpp
changeset 97 3903521a36da
parent 96 87e863f6f840
child 98 5f9e7e14eb11
--- a/engine/sqlite/src/prepare.cpp	Wed May 26 10:44:32 2010 +0100
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,763 +0,0 @@
-/*
-** 2005 May 25
-**
-** 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 the implementation of the sqlite3_prepare()
-** interface, and routines that contribute to loading the database schema
-** from disk.
-**
-** $Id: prepare.cpp 1282 2008-11-13 09:31:33Z LarsPson $
-*/
-#include "sqliteInt.h"
-#include <ctype.h>
-
-/*
-** Fill the InitData structure with an error message that indicates
-** that the database is corrupt.
-*/
-static void corruptSchema(InitData *pData, const char *zExtra){
-  if( !pData->db->mallocFailed ){
-    sqlite3SetString(pData->pzErrMsg, "malformed database schema",
-       zExtra!=0 && zExtra[0]!=0 ? " - " : (char*)0, zExtra, (char*)0);
-  }
-  pData->rc = SQLITE_CORRUPT;
-}
-
-/*
-** This is the callback routine for the code that initializes the
-** database.  See sqlite3Init() below for additional information.
-** This routine is also called from the OP_ParseSchema opcode of the VDBE.
-**
-** Each callback contains the following information:
-**
-**     argv[0] = name of thing being created
-**     argv[1] = root page number for table or index. 0 for trigger or view.
-**     argv[2] = SQL text for the CREATE statement.
-**
-*/
-int sqlite3InitCallback(void *pInit, int argc, char **argv, char **azColName){
-  InitData *pData = (InitData*)pInit;
-  sqlite3 *db = pData->db;
-  int iDb = pData->iDb;
-
-  assert( sqlite3_mutex_held(db->mutex) );
-  pData->rc = SQLITE_OK;
-  DbClearProperty(db, iDb, DB_Empty);
-  if( db->mallocFailed ){
-    corruptSchema(pData, 0);
-    return SQLITE_NOMEM;
-  }
-
-  assert( argc==3 );
-  if( argv==0 ) return 0;   /* Might happen if EMPTY_RESULT_CALLBACKS are on */
-  if( argv[1]==0 ){
-    corruptSchema(pData, 0);
-    return 1;
-  }
-  assert( iDb>=0 && iDb<db->nDb );
-  if( argv[2] && argv[2][0] ){
-    /* Call the parser to process a CREATE TABLE, INDEX or VIEW.
-    ** But because db->init.busy is set to 1, no VDBE code is generated
-    ** or executed.  All the parser does is build the internal data
-    ** structures that describe the table, index, or view.
-    */
-    char *zErr;
-    int rc;
-    assert( db->init.busy );
-    db->init.iDb = iDb;
-    db->init.newTnum = atoi(argv[1]);
-    rc = sqlite3_exec(db, argv[2], 0, 0, &zErr);
-    db->init.iDb = 0;
-    assert( rc!=SQLITE_OK || zErr==0 );
-    if( SQLITE_OK!=rc ){
-      pData->rc = rc;
-      if( rc==SQLITE_NOMEM ){
-        db->mallocFailed = 1;
-      }else if( rc!=SQLITE_INTERRUPT ){
-        corruptSchema(pData, zErr);
-      }
-      sqlite3_free(zErr);
-      return 1;
-    }
-  }else{
-    /* If the SQL column is blank it means this is an index that
-    ** was created to be the PRIMARY KEY or to fulfill a UNIQUE
-    ** constraint for a CREATE TABLE.  The index should have already
-    ** been created when we processed the CREATE TABLE.  All we have
-    ** to do here is record the root page number for that index.
-    */
-    Index *pIndex;
-    pIndex = sqlite3FindIndex(db, argv[0], db->aDb[iDb].zName);
-    if( pIndex==0 || pIndex->tnum!=0 ){
-      /* This can occur if there exists an index on a TEMP table which
-      ** has the same name as another index on a permanent index.  Since
-      ** the permanent table is hidden by the TEMP table, we can also
-      ** safely ignore the index on the permanent table.
-      */
-      /* Do Nothing */;
-    }else{
-      pIndex->tnum = atoi(argv[1]);
-    }
-  }
-  return 0;
-}
-
-/*
-** Attempt to read the database schema and initialize internal
-** data structures for a single database file.  The index of the
-** database file is given by iDb.  iDb==0 is used for the main
-** database.  iDb==1 should never be used.  iDb>=2 is used for
-** auxiliary databases.  Return one of the SQLITE_ error codes to
-** indicate success or failure.
-*/
-static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
-  int rc;
-  BtCursor *curMain;
-  int size;
-  Table *pTab;
-  Db *pDb;
-  char const *azArg[4];
-  int meta[10];
-  InitData initData;
-  char const *zMasterSchema;
-  char const *zMasterName = SCHEMA_TABLE(iDb);
-
-  /*
-  ** The master database table has a structure like this
-  */
-  static const char master_schema[] = 
-     "CREATE TABLE sqlite_master(\n"
-     "  type text,\n"
-     "  name text,\n"
-     "  tbl_name text,\n"
-     "  rootpage integer,\n"
-     "  sql text\n"
-     ")"
-  ;
-#ifndef SQLITE_OMIT_TEMPDB
-  static const char temp_master_schema[] = 
-     "CREATE TEMP TABLE sqlite_temp_master(\n"
-     "  type text,\n"
-     "  name text,\n"
-     "  tbl_name text,\n"
-     "  rootpage integer,\n"
-     "  sql text\n"
-     ")"
-  ;
-#else
-  #define temp_master_schema 0
-#endif
-
-  assert( iDb>=0 && iDb<db->nDb );
-  assert( db->aDb[iDb].pSchema );
-  assert( sqlite3_mutex_held(db->mutex) );
-
-  /* zMasterSchema and zInitScript are set to point at the master schema
-  ** and initialisation script appropriate for the database being
-  ** initialised. zMasterName is the name of the master table.
-  */
-  if( !OMIT_TEMPDB && iDb==1 ){
-    zMasterSchema = temp_master_schema;
-  }else{
-    zMasterSchema = master_schema;
-  }
-  zMasterName = SCHEMA_TABLE(iDb);
-
-  /* Construct the schema tables.  */
-  sqlite3SafetyOff(db);
-  azArg[0] = zMasterName;
-  azArg[1] = "1";
-  azArg[2] = zMasterSchema;
-  azArg[3] = 0;
-  initData.db = db;
-  initData.iDb = iDb;
-  initData.pzErrMsg = pzErrMsg;
-  rc = sqlite3InitCallback(&initData, 3, (char **)azArg, 0);
-  if( rc ){
-    sqlite3SafetyOn(db);
-    rc = initData.rc;
-    goto error_out;
-  }
-  pTab = sqlite3FindTable(db, zMasterName, db->aDb[iDb].zName);
-  if( pTab ){
-    pTab->readOnly = 1;
-  }
-  sqlite3SafetyOn(db);
-
-  /* Create a cursor to hold the database open
-  */
-  pDb = &db->aDb[iDb];
-  if( pDb->pBt==0 ){
-    if( !OMIT_TEMPDB && iDb==1 ){
-      DbSetProperty(db, 1, DB_SchemaLoaded);
-    }
-    return SQLITE_OK;
-  }
-  sqlite3BtreeEnter(pDb->pBt);
-  rc = sqlite3BtreeCursor(pDb->pBt, MASTER_ROOT, 0, 0, 0, &curMain);
-  if( rc!=SQLITE_OK && rc!=SQLITE_EMPTY ){
-    sqlite3SetString(pzErrMsg, sqlite3ErrStr(rc), (char*)0);
-    sqlite3BtreeLeave(pDb->pBt);
-    goto error_out;
-  }
-
-  /* Get the database meta information.
-  **
-  ** Meta values are as follows:
-  **    meta[0]   Schema cookie.  Changes with each schema change.
-  **    meta[1]   File format of schema layer.
-  **    meta[2]   Size of the page cache.
-  **    meta[3]   Use freelist if 0.  Autovacuum if greater than zero.
-  **    meta[4]   Db text encoding. 1:UTF-8 2:UTF-16LE 3:UTF-16BE
-  **    meta[5]   The user cookie. Used by the application.
-  **    meta[6]   Incremental-vacuum flag.
-  **    meta[7]
-  **    meta[8]
-  **    meta[9]
-  **
-  ** Note: The #defined SQLITE_UTF* symbols in sqliteInt.h correspond to
-  ** the possible values of meta[4].
-  */
-  if( rc==SQLITE_OK ){
-    int i;
-    for(i=0; rc==SQLITE_OK && i<sizeof(meta)/sizeof(meta[0]); i++){
-      rc = sqlite3BtreeGetMeta(pDb->pBt, i+1, (u32 *)&meta[i]);
-    }
-    if( rc ){
-      sqlite3SetString(pzErrMsg, sqlite3ErrStr(rc), (char*)0);
-      sqlite3BtreeCloseCursor(curMain);
-      sqlite3BtreeLeave(pDb->pBt);
-      goto error_out;
-    }
-  }else{
-    memset(meta, 0, sizeof(meta));
-  }
-  pDb->pSchema->schema_cookie = meta[0];
-
-  /* If opening a non-empty database, check the text encoding. For the
-  ** main database, set sqlite3.enc to the encoding of the main database.
-  ** For an attached db, it is an error if the encoding is not the same
-  ** as sqlite3.enc.
-  */
-  if( meta[4] ){  /* text encoding */
-    if( iDb==0 ){
-      /* If opening the main database, set ENC(db). */
-      ENC(db) = (u8)meta[4];
-      db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 6, 0);
-    }else{
-      /* If opening an attached database, the encoding much match ENC(db) */
-      if( meta[4]!=ENC(db) ){
-        sqlite3BtreeCloseCursor(curMain);
-        sqlite3SetString(pzErrMsg, "attached databases must use the same"
-            " text encoding as main database", (char*)0);
-        sqlite3BtreeLeave(pDb->pBt);
-        return SQLITE_ERROR;
-      }
-    }
-  }else{
-    DbSetProperty(db, iDb, DB_Empty);
-  }
-  pDb->pSchema->enc = ENC(db);
-
-  size = meta[2];
-  if( size==0 ){ size = SQLITE_DEFAULT_CACHE_SIZE; }
-  pDb->pSchema->cache_size = size;
-  sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
-
-  /*
-  ** file_format==1    Version 3.0.0.
-  ** file_format==2    Version 3.1.3.  // ALTER TABLE ADD COLUMN
-  ** file_format==3    Version 3.1.4.  // ditto but with non-NULL defaults
-  ** file_format==4    Version 3.3.0.  // DESC indices.  Boolean constants
-  */
-  pDb->pSchema->file_format = meta[1];
-  if( pDb->pSchema->file_format==0 ){
-    pDb->pSchema->file_format = 1;
-  }
-  if( pDb->pSchema->file_format>SQLITE_MAX_FILE_FORMAT ){
-    sqlite3BtreeCloseCursor(curMain);
-    sqlite3SetString(pzErrMsg, "unsupported file format", (char*)0);
-    sqlite3BtreeLeave(pDb->pBt);
-    return SQLITE_ERROR;
-  }
-
-  /* Ticket #2804:  When we open a database in the newer file format,
-  ** clear the legacy_file_format pragma flag so that a VACUUM will
-  ** not downgrade the database and thus invalidate any descending
-  ** indices that the user might have created.
-  */
-  if( iDb==0 && meta[1]>=4 ){
-    db->flags &= ~SQLITE_LegacyFileFmt;
-  }
-
-  /* Read the schema information out of the schema tables
-  */
-  assert( db->init.busy );
-  if( rc==SQLITE_EMPTY ){
-    /* For an empty database, there is nothing to read */
-    rc = SQLITE_OK;
-  }else{
-    char *zSql;
-    zSql = sqlite3MPrintf(db, 
-        "SELECT name, rootpage, sql FROM '%q'.%s",
-        db->aDb[iDb].zName, zMasterName);
-    sqlite3SafetyOff(db);
-#ifndef SQLITE_OMIT_AUTHORIZATION
-    {
-      int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);
-      xAuth = db->xAuth;
-      db->xAuth = 0;
-#endif
-      rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
-#ifndef SQLITE_OMIT_AUTHORIZATION
-      db->xAuth = xAuth;
-    }
-#endif
-    if( rc==SQLITE_ABORT ) rc = initData.rc;
-    sqlite3SafetyOn(db);
-    sqlite3_free(zSql);
-#ifndef SQLITE_OMIT_ANALYZE
-    if( rc==SQLITE_OK ){
-      sqlite3AnalysisLoad(db, iDb);
-    }
-#endif
-    sqlite3BtreeCloseCursor(curMain);
-  }
-  if( db->mallocFailed ){
-    /* sqlite3SetString(pzErrMsg, "out of memory", (char*)0); */
-    rc = SQLITE_NOMEM;
-    sqlite3ResetInternalSchema(db, 0);
-  }
-  if( rc==SQLITE_OK || (db->flags&SQLITE_RecoveryMode)){
-    /* Black magic: If the SQLITE_RecoveryMode flag is set, then consider
-    ** the schema loaded, even if errors occured. In this situation the 
-    ** current sqlite3_prepare() operation will fail, but the following one
-    ** will attempt to compile the supplied statement against whatever subset
-    ** of the schema was loaded before the error occured. The primary
-    ** purpose of this is to allow access to the sqlite_master table
-    ** even when its contents have been corrupted.
-    */
-    DbSetProperty(db, iDb, DB_SchemaLoaded);
-    rc = SQLITE_OK;
-  }
-  sqlite3BtreeLeave(pDb->pBt);
-
-error_out:
-  if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
-    db->mallocFailed = 1;
-  }
-  return rc;
-}
-
-/*
-** Initialize all database files - the main database file, the file
-** used to store temporary tables, and any additional database files
-** created using ATTACH statements.  Return a success code.  If an
-** error occurs, write an error message into *pzErrMsg.
-**
-** After a database is initialized, the DB_SchemaLoaded bit is set
-** bit is set in the flags field of the Db structure. If the database
-** file was of zero-length, then the DB_Empty flag is also set.
-*/
-int sqlite3Init(sqlite3 *db, char **pzErrMsg){
-  int i, rc;
-  int commit_internal = !(db->flags&SQLITE_InternChanges);
-  
-  assert( sqlite3_mutex_held(db->mutex) );
-  if( db->init.busy ) return SQLITE_OK;
-  rc = SQLITE_OK;
-  db->init.busy = 1;
-  for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
-    if( DbHasProperty(db, i, DB_SchemaLoaded) || i==1 ) continue;
-    rc = sqlite3InitOne(db, i, pzErrMsg);
-    if( rc ){
-      sqlite3ResetInternalSchema(db, i);
-    }
-  }
-
-  /* Once all the other databases have been initialised, load the schema
-  ** for the TEMP database. This is loaded last, as the TEMP database
-  ** schema may contain references to objects in other databases.
-  */
-#ifndef SQLITE_OMIT_TEMPDB
-  if( rc==SQLITE_OK && db->nDb>1 && !DbHasProperty(db, 1, DB_SchemaLoaded) ){
-    rc = sqlite3InitOne(db, 1, pzErrMsg);
-    if( rc ){
-      sqlite3ResetInternalSchema(db, 1);
-    }
-  }
-#endif
-
-  db->init.busy = 0;
-  if( rc==SQLITE_OK && commit_internal ){
-    sqlite3CommitInternalChanges(db);
-  }
-
-  return rc; 
-}
-
-/*
-** This routine is a no-op if the database schema is already initialised.
-** Otherwise, the schema is loaded. An error code is returned.
-*/
-int sqlite3ReadSchema(Parse *pParse){
-  int rc = SQLITE_OK;
-  sqlite3 *db = pParse->db;
-  assert( sqlite3_mutex_held(db->mutex) );
-  if( !db->init.busy ){
-    rc = sqlite3Init(db, &pParse->zErrMsg);
-  }
-  if( rc!=SQLITE_OK ){
-    pParse->rc = rc;
-    pParse->nErr++;
-  }
-  return rc;
-}
-
-
-/*
-** Check schema cookies in all databases.  If any cookie is out
-** of date, return 0.  If all schema cookies are current, return 1.
-*/
-static int schemaIsValid(sqlite3 *db){
-  int iDb;
-  int rc;
-  BtCursor *curTemp;
-  int cookie;
-  int allOk = 1;
-
-  assert( sqlite3_mutex_held(db->mutex) );
-  for(iDb=0; allOk && iDb<db->nDb; iDb++){
-    Btree *pBt;
-    pBt = db->aDb[iDb].pBt;
-    if( pBt==0 ) continue;
-    rc = sqlite3BtreeCursor(pBt, MASTER_ROOT, 0, 0, 0, &curTemp);
-    if( rc==SQLITE_OK ){
-      rc = sqlite3BtreeGetMeta(pBt, 1, (u32 *)&cookie);
-      if( rc==SQLITE_OK && cookie!=db->aDb[iDb].pSchema->schema_cookie ){
-        allOk = 0;
-      }
-      sqlite3BtreeCloseCursor(curTemp);
-    }
-    if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
-      db->mallocFailed = 1;
-    }
-  }
-  return allOk;
-}
-
-/*
-** Convert a schema pointer into the iDb index that indicates
-** which database file in db->aDb[] the schema refers to.
-**
-** If the same database is attached more than once, the first
-** attached database is returned.
-*/
-int sqlite3SchemaToIndex(sqlite3 *db, Schema *pSchema){
-  int i = -1000000;
-
-  /* If pSchema is NULL, then return -1000000. This happens when code in 
-  ** expr.c is trying to resolve a reference to a transient table (i.e. one
-  ** created by a sub-select). In this case the return value of this 
-  ** function should never be used.
-  **
-  ** We return -1000000 instead of the more usual -1 simply because using
-  ** -1000000 as incorrectly using -1000000 index into db->aDb[] is much 
-  ** more likely to cause a segfault than -1 (of course there are assert()
-  ** statements too, but it never hurts to play the odds).
-  */
-  assert( sqlite3_mutex_held(db->mutex) );
-  if( pSchema ){
-    for(i=0; i<db->nDb; i++){
-      if( db->aDb[i].pSchema==pSchema ){
-        break;
-      }
-    }
-    assert( i>=0 &&i>=0 &&  i<db->nDb );
-  }
-  return i;
-}
-
-/*
-** Compile the UTF-8 encoded SQL statement zSql into a statement handle.
-*/
-int sqlite3Prepare(
-  sqlite3 *db,              /* Database handle. */
-  const char *zSql,         /* UTF-8 encoded SQL statement. */
-  int nBytes,               /* Length of zSql in bytes. */
-  int saveSqlFlag,          /* True to copy SQL text into the sqlite3_stmt */
-  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
-  const char **pzTail       /* OUT: End of parsed string */
-){
-  Parse sParse;
-  char *zErrMsg = 0;
-  int rc = SQLITE_OK;
-  int i;
-
-  assert( ppStmt );
-  *ppStmt = 0;
-  if( sqlite3SafetyOn(db) ){
-    return SQLITE_MISUSE;
-  }
-  assert( !db->mallocFailed );
-  assert( sqlite3_mutex_held(db->mutex) );
-
-  /* If any attached database schemas are locked, do not proceed with
-  ** compilation. Instead return SQLITE_LOCKED immediately.
-  */
-  for(i=0; i<db->nDb; i++) {
-    Btree *pBt = db->aDb[i].pBt;
-    if( pBt ){
-      int rc;
-      rc = sqlite3BtreeSchemaLocked(pBt);
-      if( rc ){
-        const char *zDb = db->aDb[i].zName;
-        sqlite3Error(db, SQLITE_LOCKED, "database schema is locked: %s", zDb);
-        sqlite3SafetyOff(db);
-        return SQLITE_LOCKED;
-      }
-    }
-  }
-  
-  memset(&sParse, 0, sizeof(sParse));
-  sParse.db = db;
-  if( nBytes>=0 && zSql[nBytes]!=0 ){
-    char *zSqlCopy;
-    if( nBytes>SQLITE_MAX_SQL_LENGTH ){
-      return SQLITE_TOOBIG;
-    }
-    zSqlCopy = sqlite3DbStrNDup(db, zSql, nBytes);
-    if( zSqlCopy ){
-      sqlite3RunParser(&sParse, zSqlCopy, &zErrMsg);
-      sqlite3_free(zSqlCopy);
-    }
-    sParse.zTail = &zSql[nBytes];
-  }else{
-    sqlite3RunParser(&sParse, zSql, &zErrMsg);
-  }
-
-  if( db->mallocFailed ){
-    sParse.rc = SQLITE_NOMEM;
-  }
-  if( sParse.rc==SQLITE_DONE ) sParse.rc = SQLITE_OK;
-  if( sParse.checkSchema && !schemaIsValid(db) ){
-    sParse.rc = SQLITE_SCHEMA;
-  }
-  if( sParse.rc==SQLITE_SCHEMA ){
-    sqlite3ResetInternalSchema(db, 0);
-  }
-  if( db->mallocFailed ){
-    sParse.rc = SQLITE_NOMEM;
-  }
-  if( pzTail ){
-    *pzTail = sParse.zTail;
-  }
-  rc = sParse.rc;
-
-#ifndef SQLITE_OMIT_EXPLAIN
-  if( rc==SQLITE_OK && sParse.pVdbe && sParse.explain ){
-    if( sParse.explain==2 ){
-      sqlite3VdbeSetNumCols(sParse.pVdbe, 3);
-      sqlite3VdbeSetColName(sParse.pVdbe, 0, COLNAME_NAME, "order", P3_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 1, COLNAME_NAME, "from", P3_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 2, COLNAME_NAME, "detail", P3_STATIC);
-    }else{
-      sqlite3VdbeSetNumCols(sParse.pVdbe, 5);
-      sqlite3VdbeSetColName(sParse.pVdbe, 0, COLNAME_NAME, "addr", P3_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 1, COLNAME_NAME, "opcode", P3_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 2, COLNAME_NAME, "p1", P3_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 3, COLNAME_NAME, "p2", P3_STATIC);
-      sqlite3VdbeSetColName(sParse.pVdbe, 4, COLNAME_NAME, "p3", P3_STATIC);
-    }
-  }
-#endif
-
-  if( sqlite3SafetyOff(db) ){
-    rc = SQLITE_MISUSE;
-  }
-
-  if( saveSqlFlag ){
-    sqlite3VdbeSetSql(sParse.pVdbe, zSql, sParse.zTail - zSql);
-  }
-  if( rc!=SQLITE_OK || db->mallocFailed ){
-    sqlite3_finalize((sqlite3_stmt*)sParse.pVdbe);
-    assert(!(*ppStmt));
-  }else{
-    *ppStmt = (sqlite3_stmt*)sParse.pVdbe;
-  }
-
-  if( zErrMsg ){
-    sqlite3Error(db, rc, "%s", zErrMsg);
-    sqlite3_free(zErrMsg);
-  }else{
-    sqlite3Error(db, rc, 0);
-  }
-
-  rc = sqlite3ApiExit(db, rc);
-  /* sqlite3ReleaseThreadData(); */
-  assert( (rc&db->errMask)==rc );
-  return rc;
-}
-static int sqlite3LockAndPrepare(
-  sqlite3 *db,              /* Database handle. */
-  const char *zSql,         /* UTF-8 encoded SQL statement. */
-  int nBytes,               /* Length of zSql in bytes. */
-  int saveSqlFlag,          /* True to copy SQL text into the sqlite3_stmt */
-  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
-  const char **pzTail       /* OUT: End of parsed string */
-){
-  int rc;
-  if( sqlite3SafetyCheck(db) ){
-    return SQLITE_MISUSE;
-  }
-  sqlite3_mutex_enter(db->mutex);
-  sqlite3BtreeEnterAll(db);
-  rc = sqlite3Prepare(db, zSql, nBytes, saveSqlFlag, ppStmt, pzTail);
-  sqlite3BtreeLeaveAll(db);
-  sqlite3_mutex_leave(db->mutex);
-  return rc;
-}
-
-/*
-** Rerun the compilation of a statement after a schema change.
-** Return true if the statement was recompiled successfully.
-** Return false if there is an error of some kind.
-*/
-int sqlite3Reprepare(Vdbe *p){
-  int rc;
-  sqlite3_stmt *pNew;
-  const char *zSql;
-  sqlite3 *db;
-
-  assert( sqlite3_mutex_held(sqlite3VdbeDb(p)->mutex) );
-  zSql = sqlite3_sql((sqlite3_stmt *)p);
-  if( zSql==0 ){
-    return 0;
-  }
-  db = sqlite3VdbeDb(p);
-  assert( sqlite3_mutex_held(db->mutex) );
-  rc = sqlite3LockAndPrepare(db, zSql, -1, 0, &pNew, 0);
-  if( rc ){
-    if( rc==SQLITE_NOMEM ){
-      db->mallocFailed = 1;
-    }
-    assert( pNew==0 );
-    return 0;
-  }else{
-    assert( pNew!=0 );
-  }
-  sqlite3VdbeSwap((Vdbe*)pNew, p);
-  sqlite3_transfer_bindings(pNew, (sqlite3_stmt*)p);
-  sqlite3VdbeResetStepResult((Vdbe*)pNew);
-  sqlite3VdbeFinalize((Vdbe*)pNew);
-  return 1;
-}
-
-
-/*
-** Two versions of the official API.  Legacy and new use.  In the legacy
-** version, the original SQL text is not saved in the prepared statement
-** and so if a schema change occurs, SQLITE_SCHEMA is returned by
-** sqlite3_step().  In the new version, the original SQL text is retained
-** and the statement is automatically recompiled if an schema change
-** occurs.
-*/
-EXPORT_C int sqlite3_prepare(
-  sqlite3 *db,              /* Database handle. */
-  const char *zSql,         /* UTF-8 encoded SQL statement. */
-  int nBytes,               /* Length of zSql in bytes. */
-  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
-  const char **pzTail       /* OUT: End of parsed string */
-){
-  return sqlite3LockAndPrepare(db,zSql,nBytes,0,ppStmt,pzTail);
-}
-EXPORT_C int sqlite3_prepare_v2(
-  sqlite3 *db,              /* Database handle. */
-  const char *zSql,         /* UTF-8 encoded SQL statement. */
-  int nBytes,               /* Length of zSql in bytes. */
-  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
-  const char **pzTail       /* OUT: End of parsed string */
-){
-  return sqlite3LockAndPrepare(db,zSql,nBytes,1,ppStmt,pzTail);
-}
-
-
-#ifndef SQLITE_OMIT_UTF16
-/*
-** Compile the UTF-16 encoded SQL statement zSql into a statement handle.
-*/
-static int sqlite3Prepare16(
-  sqlite3 *db,              /* Database handle. */ 
-  const void *zSql,         /* UTF-8 encoded SQL statement. */
-  int nBytes,               /* Length of zSql in bytes. */
-  int saveSqlFlag,          /* True to save SQL text into the sqlite3_stmt */
-  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
-  const void **pzTail       /* OUT: End of parsed string */
-){
-  /* This function currently works by first transforming the UTF-16
-  ** encoded string to UTF-8, then invoking sqlite3_prepare(). The
-  ** tricky bit is figuring out the pointer to return in *pzTail.
-  */
-  char *zSql8;
-  const char *zTail8 = 0;
-  int rc = SQLITE_OK;
-
-  if( sqlite3SafetyCheck(db) ){
-    return SQLITE_MISUSE;
-  }
-  sqlite3_mutex_enter(db->mutex);
-  zSql8 = sqlite3Utf16to8(db, zSql, nBytes);
-  if( zSql8 ){
-    rc = sqlite3LockAndPrepare(db, zSql8, -1, saveSqlFlag, ppStmt, &zTail8);
-  }
-
-  if( zTail8 && pzTail ){
-    /* If sqlite3_prepare returns a tail pointer, we calculate the
-    ** equivalent pointer into the UTF-16 string by counting the unicode
-    ** characters between zSql8 and zTail8, and then returning a pointer
-    ** the same number of characters into the UTF-16 string.
-    */
-    int chars_parsed = sqlite3Utf8CharLen(zSql8, zTail8-zSql8);
-    *pzTail = (u8 *)zSql + sqlite3Utf16ByteLen(zSql, chars_parsed);
-  }
-  sqlite3_free(zSql8); 
-  rc = sqlite3ApiExit(db, rc);
-  sqlite3_mutex_leave(db->mutex);
-  return rc;
-}
-
-/*
-** Two versions of the official API.  Legacy and new use.  In the legacy
-** version, the original SQL text is not saved in the prepared statement
-** and so if a schema change occurs, SQLITE_SCHEMA is returned by
-** sqlite3_step().  In the new version, the original SQL text is retained
-** and the statement is automatically recompiled if an schema change
-** occurs.
-*/
-EXPORT_C int sqlite3_prepare16(
-  sqlite3 *db,              /* Database handle. */ 
-  const void *zSql,         /* UTF-8 encoded SQL statement. */
-  int nBytes,               /* Length of zSql in bytes. */
-  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
-  const void **pzTail       /* OUT: End of parsed string */
-){
-  return sqlite3Prepare16(db,zSql,nBytes,0,ppStmt,pzTail);
-}
-EXPORT_C int sqlite3_prepare16_v2(
-  sqlite3 *db,              /* Database handle. */ 
-  const void *zSql,         /* UTF-8 encoded SQL statement. */
-  int nBytes,               /* Length of zSql in bytes. */
-  sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
-  const void **pzTail       /* OUT: End of parsed string */
-){
-  return sqlite3Prepare16(db,zSql,nBytes,1,ppStmt,pzTail);
-}
-
-#endif /* SQLITE_OMIT_UTF16 */