sl@0: /*
sl@0: ** 2005 May 25
sl@0: **
sl@0: ** The author disclaims copyright to this source code.  In place of
sl@0: ** a legal notice, here is a blessing:
sl@0: **
sl@0: **    May you do good and not evil.
sl@0: **    May you find forgiveness for yourself and forgive others.
sl@0: **    May you share freely, never taking more than you give.
sl@0: **
sl@0: *************************************************************************
sl@0: ** This file contains the implementation of the sqlite3_prepare()
sl@0: ** interface, and routines that contribute to loading the database schema
sl@0: ** from disk.
sl@0: **
sl@0: ** $Id: prepare.c,v 1.97 2008/09/08 09:06:19 danielk1977 Exp $
sl@0: */
sl@0: #include "sqliteInt.h"
sl@0: #include <ctype.h>
sl@0: 
sl@0: /*
sl@0: ** Fill the InitData structure with an error message that indicates
sl@0: ** that the database is corrupt.
sl@0: */
sl@0: static void corruptSchema(
sl@0:   InitData *pData,     /* Initialization context */
sl@0:   const char *zObj,    /* Object being parsed at the point of error */
sl@0:   const char *zExtra   /* Error information */
sl@0: ){
sl@0:   sqlite3 *db = pData->db;
sl@0:   if( !db->mallocFailed && (db->flags & SQLITE_RecoveryMode)==0 ){
sl@0:     if( zObj==0 ) zObj = "?";
sl@0:     sqlite3SetString(pData->pzErrMsg, pData->db,
sl@0:        "malformed database schema (%s)", zObj);
sl@0:     if( zExtra && zExtra[0] ){
sl@0:       *pData->pzErrMsg = sqlite3MAppendf(pData->db, *pData->pzErrMsg, "%s - %s",
sl@0:                                   *pData->pzErrMsg, zExtra);
sl@0:     }
sl@0:   }
sl@0:   pData->rc = SQLITE_CORRUPT;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** This is the callback routine for the code that initializes the
sl@0: ** database.  See sqlite3Init() below for additional information.
sl@0: ** This routine is also called from the OP_ParseSchema opcode of the VDBE.
sl@0: **
sl@0: ** Each callback contains the following information:
sl@0: **
sl@0: **     argv[0] = name of thing being created
sl@0: **     argv[1] = root page number for table or index. 0 for trigger or view.
sl@0: **     argv[2] = SQL text for the CREATE statement.
sl@0: **
sl@0: */
sl@0: int sqlite3InitCallback(void *pInit, int argc, char **argv, char **azColName){
sl@0:   InitData *pData = (InitData*)pInit;
sl@0:   sqlite3 *db = pData->db;
sl@0:   int iDb = pData->iDb;
sl@0: 
sl@0:   assert( sqlite3_mutex_held(db->mutex) );
sl@0:   DbClearProperty(db, iDb, DB_Empty);
sl@0:   if( db->mallocFailed ){
sl@0:     corruptSchema(pData, argv[0], 0);
sl@0:     return SQLITE_NOMEM;
sl@0:   }
sl@0: 
sl@0:   assert( argc==3 );
sl@0:   assert( iDb>=0 && iDb<db->nDb );
sl@0:   if( argv==0 ) return 0;   /* Might happen if EMPTY_RESULT_CALLBACKS are on */
sl@0:   if( argv[1]==0 ){
sl@0:     corruptSchema(pData, argv[0], 0);
sl@0:   }else if( argv[2] && argv[2][0] ){
sl@0:     /* Call the parser to process a CREATE TABLE, INDEX or VIEW.
sl@0:     ** But because db->init.busy is set to 1, no VDBE code is generated
sl@0:     ** or executed.  All the parser does is build the internal data
sl@0:     ** structures that describe the table, index, or view.
sl@0:     */
sl@0:     char *zErr;
sl@0:     int rc;
sl@0:     u8 lookasideEnabled;
sl@0:     assert( db->init.busy );
sl@0:     db->init.iDb = iDb;
sl@0:     db->init.newTnum = atoi(argv[1]);
sl@0:     lookasideEnabled = db->lookaside.bEnabled;
sl@0:     db->lookaside.bEnabled = 0;
sl@0:     rc = sqlite3_exec(db, argv[2], 0, 0, &zErr);
sl@0:     db->init.iDb = 0;
sl@0:     db->lookaside.bEnabled = lookasideEnabled;
sl@0:     assert( rc!=SQLITE_OK || zErr==0 );
sl@0:     if( SQLITE_OK!=rc ){
sl@0:       pData->rc = rc;
sl@0:       if( rc==SQLITE_NOMEM ){
sl@0:         db->mallocFailed = 1;
sl@0:       }else if( rc!=SQLITE_INTERRUPT ){
sl@0:         corruptSchema(pData, argv[0], zErr);
sl@0:       }
sl@0:       sqlite3DbFree(db, zErr);
sl@0:     }
sl@0:   }else if( argv[0]==0 ){
sl@0:     corruptSchema(pData, 0, 0);
sl@0:   }else{
sl@0:     /* If the SQL column is blank it means this is an index that
sl@0:     ** was created to be the PRIMARY KEY or to fulfill a UNIQUE
sl@0:     ** constraint for a CREATE TABLE.  The index should have already
sl@0:     ** been created when we processed the CREATE TABLE.  All we have
sl@0:     ** to do here is record the root page number for that index.
sl@0:     */
sl@0:     Index *pIndex;
sl@0:     pIndex = sqlite3FindIndex(db, argv[0], db->aDb[iDb].zName);
sl@0:     if( pIndex==0 || pIndex->tnum!=0 ){
sl@0:       /* This can occur if there exists an index on a TEMP table which
sl@0:       ** has the same name as another index on a permanent index.  Since
sl@0:       ** the permanent table is hidden by the TEMP table, we can also
sl@0:       ** safely ignore the index on the permanent table.
sl@0:       */
sl@0:       /* Do Nothing */;
sl@0:     }else{
sl@0:       pIndex->tnum = atoi(argv[1]);
sl@0:     }
sl@0:   }
sl@0:   return 0;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Attempt to read the database schema and initialize internal
sl@0: ** data structures for a single database file.  The index of the
sl@0: ** database file is given by iDb.  iDb==0 is used for the main
sl@0: ** database.  iDb==1 should never be used.  iDb>=2 is used for
sl@0: ** auxiliary databases.  Return one of the SQLITE_ error codes to
sl@0: ** indicate success or failure.
sl@0: */
sl@0: static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
sl@0:   int rc;
sl@0:   BtCursor *curMain;
sl@0:   int size;
sl@0:   Table *pTab;
sl@0:   Db *pDb;
sl@0:   char const *azArg[4];
sl@0:   int meta[10];
sl@0:   InitData initData;
sl@0:   char const *zMasterSchema;
sl@0:   char const *zMasterName = SCHEMA_TABLE(iDb);
sl@0: 
sl@0:   /*
sl@0:   ** The master database table has a structure like this
sl@0:   */
sl@0:   static const char master_schema[] = 
sl@0:      "CREATE TABLE sqlite_master(\n"
sl@0:      "  type text,\n"
sl@0:      "  name text,\n"
sl@0:      "  tbl_name text,\n"
sl@0:      "  rootpage integer,\n"
sl@0:      "  sql text\n"
sl@0:      ")"
sl@0:   ;
sl@0: #ifndef SQLITE_OMIT_TEMPDB
sl@0:   static const char temp_master_schema[] = 
sl@0:      "CREATE TEMP TABLE sqlite_temp_master(\n"
sl@0:      "  type text,\n"
sl@0:      "  name text,\n"
sl@0:      "  tbl_name text,\n"
sl@0:      "  rootpage integer,\n"
sl@0:      "  sql text\n"
sl@0:      ")"
sl@0:   ;
sl@0: #else
sl@0:   #define temp_master_schema 0
sl@0: #endif
sl@0: 
sl@0:   assert( iDb>=0 && iDb<db->nDb );
sl@0:   assert( db->aDb[iDb].pSchema );
sl@0:   assert( sqlite3_mutex_held(db->mutex) );
sl@0:   assert( iDb==1 || sqlite3BtreeHoldsMutex(db->aDb[iDb].pBt) );
sl@0: 
sl@0:   /* zMasterSchema and zInitScript are set to point at the master schema
sl@0:   ** and initialisation script appropriate for the database being
sl@0:   ** initialised. zMasterName is the name of the master table.
sl@0:   */
sl@0:   if( !OMIT_TEMPDB && iDb==1 ){
sl@0:     zMasterSchema = temp_master_schema;
sl@0:   }else{
sl@0:     zMasterSchema = master_schema;
sl@0:   }
sl@0:   zMasterName = SCHEMA_TABLE(iDb);
sl@0: 
sl@0:   /* Construct the schema tables.  */
sl@0:   azArg[0] = zMasterName;
sl@0:   azArg[1] = "1";
sl@0:   azArg[2] = zMasterSchema;
sl@0:   azArg[3] = 0;
sl@0:   initData.db = db;
sl@0:   initData.iDb = iDb;
sl@0:   initData.rc = SQLITE_OK;
sl@0:   initData.pzErrMsg = pzErrMsg;
sl@0:   (void)sqlite3SafetyOff(db);
sl@0:   sqlite3InitCallback(&initData, 3, (char **)azArg, 0);
sl@0:   (void)sqlite3SafetyOn(db);
sl@0:   if( initData.rc ){
sl@0:     rc = initData.rc;
sl@0:     goto error_out;
sl@0:   }
sl@0:   pTab = sqlite3FindTable(db, zMasterName, db->aDb[iDb].zName);
sl@0:   if( pTab ){
sl@0:     pTab->tabFlags |= TF_Readonly;
sl@0:   }
sl@0: 
sl@0:   /* Create a cursor to hold the database open
sl@0:   */
sl@0:   pDb = &db->aDb[iDb];
sl@0:   if( pDb->pBt==0 ){
sl@0:     if( !OMIT_TEMPDB && iDb==1 ){
sl@0:       DbSetProperty(db, 1, DB_SchemaLoaded);
sl@0:     }
sl@0:     return SQLITE_OK;
sl@0:   }
sl@0:   curMain = sqlite3MallocZero(sqlite3BtreeCursorSize());
sl@0:   if( !curMain ){
sl@0:     rc = SQLITE_NOMEM;
sl@0:     goto error_out;
sl@0:   }
sl@0:   sqlite3BtreeEnter(pDb->pBt);
sl@0:   rc = sqlite3BtreeCursor(pDb->pBt, MASTER_ROOT, 0, 0, curMain);
sl@0:   if( rc!=SQLITE_OK && rc!=SQLITE_EMPTY ){
sl@0:     sqlite3SetString(pzErrMsg, db, "%s", sqlite3ErrStr(rc));
sl@0:     goto initone_error_out;
sl@0:   }
sl@0: 
sl@0:   /* Get the database meta information.
sl@0:   **
sl@0:   ** Meta values are as follows:
sl@0:   **    meta[0]   Schema cookie.  Changes with each schema change.
sl@0:   **    meta[1]   File format of schema layer.
sl@0:   **    meta[2]   Size of the page cache.
sl@0:   **    meta[3]   Use freelist if 0.  Autovacuum if greater than zero.
sl@0:   **    meta[4]   Db text encoding. 1:UTF-8 2:UTF-16LE 3:UTF-16BE
sl@0:   **    meta[5]   The user cookie. Used by the application.
sl@0:   **    meta[6]   Incremental-vacuum flag.
sl@0:   **    meta[7]
sl@0:   **    meta[8]
sl@0:   **    meta[9]
sl@0:   **
sl@0:   ** Note: The #defined SQLITE_UTF* symbols in sqliteInt.h correspond to
sl@0:   ** the possible values of meta[4].
sl@0:   */
sl@0:   if( rc==SQLITE_OK ){
sl@0:     int i;
sl@0:     for(i=0; i<sizeof(meta)/sizeof(meta[0]); i++){
sl@0:       rc = sqlite3BtreeGetMeta(pDb->pBt, i+1, (u32 *)&meta[i]);
sl@0:       if( rc ){
sl@0:         sqlite3SetString(pzErrMsg, db, "%s", sqlite3ErrStr(rc));
sl@0:         goto initone_error_out;
sl@0:       }
sl@0:     }
sl@0:   }else{
sl@0:     memset(meta, 0, sizeof(meta));
sl@0:   }
sl@0:   pDb->pSchema->schema_cookie = meta[0];
sl@0: 
sl@0:   /* If opening a non-empty database, check the text encoding. For the
sl@0:   ** main database, set sqlite3.enc to the encoding of the main database.
sl@0:   ** For an attached db, it is an error if the encoding is not the same
sl@0:   ** as sqlite3.enc.
sl@0:   */
sl@0:   if( meta[4] ){  /* text encoding */
sl@0:     if( iDb==0 ){
sl@0:       /* If opening the main database, set ENC(db). */
sl@0:       ENC(db) = (u8)meta[4];
sl@0:       db->pDfltColl = sqlite3FindCollSeq(db, SQLITE_UTF8, "BINARY", 6, 0);
sl@0:     }else{
sl@0:       /* If opening an attached database, the encoding much match ENC(db) */
sl@0:       if( meta[4]!=ENC(db) ){
sl@0:         sqlite3SetString(pzErrMsg, db, "attached databases must use the same"
sl@0:             " text encoding as main database");
sl@0:         rc = SQLITE_ERROR;
sl@0:         goto initone_error_out;
sl@0:       }
sl@0:     }
sl@0:   }else{
sl@0:     DbSetProperty(db, iDb, DB_Empty);
sl@0:   }
sl@0:   pDb->pSchema->enc = ENC(db);
sl@0: 
sl@0:   if( pDb->pSchema->cache_size==0 ){
sl@0:     size = meta[2];
sl@0:     if( size==0 ){ size = SQLITE_DEFAULT_CACHE_SIZE; }
sl@0:     if( size<0 ) size = -size;
sl@0:     pDb->pSchema->cache_size = size;
sl@0:     sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
sl@0:   }
sl@0: 
sl@0:   /*
sl@0:   ** file_format==1    Version 3.0.0.
sl@0:   ** file_format==2    Version 3.1.3.  // ALTER TABLE ADD COLUMN
sl@0:   ** file_format==3    Version 3.1.4.  // ditto but with non-NULL defaults
sl@0:   ** file_format==4    Version 3.3.0.  // DESC indices.  Boolean constants
sl@0:   */
sl@0:   pDb->pSchema->file_format = meta[1];
sl@0:   if( pDb->pSchema->file_format==0 ){
sl@0:     pDb->pSchema->file_format = 1;
sl@0:   }
sl@0:   if( pDb->pSchema->file_format>SQLITE_MAX_FILE_FORMAT ){
sl@0:     sqlite3SetString(pzErrMsg, db, "unsupported file format");
sl@0:     rc = SQLITE_ERROR;
sl@0:     goto initone_error_out;
sl@0:   }
sl@0: 
sl@0:   /* Ticket #2804:  When we open a database in the newer file format,
sl@0:   ** clear the legacy_file_format pragma flag so that a VACUUM will
sl@0:   ** not downgrade the database and thus invalidate any descending
sl@0:   ** indices that the user might have created.
sl@0:   */
sl@0:   if( iDb==0 && meta[1]>=4 ){
sl@0:     db->flags &= ~SQLITE_LegacyFileFmt;
sl@0:   }
sl@0: 
sl@0:   /* Read the schema information out of the schema tables
sl@0:   */
sl@0:   assert( db->init.busy );
sl@0:   if( rc==SQLITE_EMPTY ){
sl@0:     /* For an empty database, there is nothing to read */
sl@0:     rc = SQLITE_OK;
sl@0:   }else{
sl@0:     char *zSql;
sl@0:     zSql = sqlite3MPrintf(db, 
sl@0:         "SELECT name, rootpage, sql FROM '%q'.%s",
sl@0:         db->aDb[iDb].zName, zMasterName);
sl@0:     (void)sqlite3SafetyOff(db);
sl@0: #ifndef SQLITE_OMIT_AUTHORIZATION
sl@0:     {
sl@0:       int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);
sl@0:       xAuth = db->xAuth;
sl@0:       db->xAuth = 0;
sl@0: #endif
sl@0:       rc = sqlite3_exec(db, zSql, sqlite3InitCallback, &initData, 0);
sl@0: #ifndef SQLITE_OMIT_AUTHORIZATION
sl@0:       db->xAuth = xAuth;
sl@0:     }
sl@0: #endif
sl@0:     if( rc==SQLITE_OK ) rc = initData.rc;
sl@0:     (void)sqlite3SafetyOn(db);
sl@0:     sqlite3DbFree(db, zSql);
sl@0: #ifndef SQLITE_OMIT_ANALYZE
sl@0:     if( rc==SQLITE_OK ){
sl@0:       sqlite3AnalysisLoad(db, iDb);
sl@0:     }
sl@0: #endif
sl@0:   }
sl@0:   if( db->mallocFailed ){
sl@0:     rc = SQLITE_NOMEM;
sl@0:     sqlite3ResetInternalSchema(db, 0);
sl@0:   }
sl@0:   if( rc==SQLITE_OK || (db->flags&SQLITE_RecoveryMode)){
sl@0:     /* Black magic: If the SQLITE_RecoveryMode flag is set, then consider
sl@0:     ** the schema loaded, even if errors occured. In this situation the 
sl@0:     ** current sqlite3_prepare() operation will fail, but the following one
sl@0:     ** will attempt to compile the supplied statement against whatever subset
sl@0:     ** of the schema was loaded before the error occured. The primary
sl@0:     ** purpose of this is to allow access to the sqlite_master table
sl@0:     ** even when its contents have been corrupted.
sl@0:     */
sl@0:     DbSetProperty(db, iDb, DB_SchemaLoaded);
sl@0:     rc = SQLITE_OK;
sl@0:   }
sl@0: 
sl@0:   /* Jump here for an error that occurs after successfully allocating
sl@0:   ** curMain and calling sqlite3BtreeEnter(). For an error that occurs
sl@0:   ** before that point, jump to error_out.
sl@0:   */
sl@0: initone_error_out:
sl@0:   sqlite3BtreeCloseCursor(curMain);
sl@0:   sqlite3_free(curMain);
sl@0:   sqlite3BtreeLeave(pDb->pBt);
sl@0: 
sl@0: error_out:
sl@0:   if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
sl@0:     db->mallocFailed = 1;
sl@0:   }
sl@0:   return rc;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Initialize all database files - the main database file, the file
sl@0: ** used to store temporary tables, and any additional database files
sl@0: ** created using ATTACH statements.  Return a success code.  If an
sl@0: ** error occurs, write an error message into *pzErrMsg.
sl@0: **
sl@0: ** After a database is initialized, the DB_SchemaLoaded bit is set
sl@0: ** bit is set in the flags field of the Db structure. If the database
sl@0: ** file was of zero-length, then the DB_Empty flag is also set.
sl@0: */
sl@0: int sqlite3Init(sqlite3 *db, char **pzErrMsg){
sl@0:   int i, rc;
sl@0:   int commit_internal = !(db->flags&SQLITE_InternChanges);
sl@0:   
sl@0:   assert( sqlite3_mutex_held(db->mutex) );
sl@0:   if( db->init.busy ) return SQLITE_OK;
sl@0:   rc = SQLITE_OK;
sl@0:   db->init.busy = 1;
sl@0:   for(i=0; rc==SQLITE_OK && i<db->nDb; i++){
sl@0:     if( DbHasProperty(db, i, DB_SchemaLoaded) || i==1 ) continue;
sl@0:     rc = sqlite3InitOne(db, i, pzErrMsg);
sl@0:     if( rc ){
sl@0:       sqlite3ResetInternalSchema(db, i);
sl@0:     }
sl@0:   }
sl@0: 
sl@0:   /* Once all the other databases have been initialised, load the schema
sl@0:   ** for the TEMP database. This is loaded last, as the TEMP database
sl@0:   ** schema may contain references to objects in other databases.
sl@0:   */
sl@0: #ifndef SQLITE_OMIT_TEMPDB
sl@0:   if( rc==SQLITE_OK && db->nDb>1 && !DbHasProperty(db, 1, DB_SchemaLoaded) ){
sl@0:     rc = sqlite3InitOne(db, 1, pzErrMsg);
sl@0:     if( rc ){
sl@0:       sqlite3ResetInternalSchema(db, 1);
sl@0:     }
sl@0:   }
sl@0: #endif
sl@0: 
sl@0:   db->init.busy = 0;
sl@0:   if( rc==SQLITE_OK && commit_internal ){
sl@0:     sqlite3CommitInternalChanges(db);
sl@0:   }
sl@0: 
sl@0:   return rc; 
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** This routine is a no-op if the database schema is already initialised.
sl@0: ** Otherwise, the schema is loaded. An error code is returned.
sl@0: */
sl@0: int sqlite3ReadSchema(Parse *pParse){
sl@0:   int rc = SQLITE_OK;
sl@0:   sqlite3 *db = pParse->db;
sl@0:   assert( sqlite3_mutex_held(db->mutex) );
sl@0:   if( !db->init.busy ){
sl@0:     rc = sqlite3Init(db, &pParse->zErrMsg);
sl@0:   }
sl@0:   if( rc!=SQLITE_OK ){
sl@0:     pParse->rc = rc;
sl@0:     pParse->nErr++;
sl@0:   }
sl@0:   return rc;
sl@0: }
sl@0: 
sl@0: 
sl@0: /*
sl@0: ** Check schema cookies in all databases.  If any cookie is out
sl@0: ** of date, return 0.  If all schema cookies are current, return 1.
sl@0: */
sl@0: static int schemaIsValid(sqlite3 *db){
sl@0:   int iDb;
sl@0:   int rc;
sl@0:   BtCursor *curTemp;
sl@0:   int cookie;
sl@0:   int allOk = 1;
sl@0: 
sl@0:   curTemp = (BtCursor *)sqlite3Malloc(sqlite3BtreeCursorSize());
sl@0:   if( curTemp ){
sl@0:     assert( sqlite3_mutex_held(db->mutex) );
sl@0:     for(iDb=0; allOk && iDb<db->nDb; iDb++){
sl@0:       Btree *pBt;
sl@0:       pBt = db->aDb[iDb].pBt;
sl@0:       if( pBt==0 ) continue;
sl@0:       memset(curTemp, 0, sqlite3BtreeCursorSize());
sl@0:       rc = sqlite3BtreeCursor(pBt, MASTER_ROOT, 0, 0, curTemp);
sl@0:       if( rc==SQLITE_OK ){
sl@0:         rc = sqlite3BtreeGetMeta(pBt, 1, (u32 *)&cookie);
sl@0:         if( rc==SQLITE_OK && cookie!=db->aDb[iDb].pSchema->schema_cookie ){
sl@0:           allOk = 0;
sl@0:         }
sl@0:         sqlite3BtreeCloseCursor(curTemp);
sl@0:       }
sl@0:       if( rc==SQLITE_NOMEM || rc==SQLITE_IOERR_NOMEM ){
sl@0:         db->mallocFailed = 1;
sl@0:       }
sl@0:     }
sl@0:     sqlite3_free(curTemp);
sl@0:   }else{
sl@0:     allOk = 0;
sl@0:     db->mallocFailed = 1;
sl@0:   }
sl@0: 
sl@0:   return allOk;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Convert a schema pointer into the iDb index that indicates
sl@0: ** which database file in db->aDb[] the schema refers to.
sl@0: **
sl@0: ** If the same database is attached more than once, the first
sl@0: ** attached database is returned.
sl@0: */
sl@0: int sqlite3SchemaToIndex(sqlite3 *db, Schema *pSchema){
sl@0:   int i = -1000000;
sl@0: 
sl@0:   /* If pSchema is NULL, then return -1000000. This happens when code in 
sl@0:   ** expr.c is trying to resolve a reference to a transient table (i.e. one
sl@0:   ** created by a sub-select). In this case the return value of this 
sl@0:   ** function should never be used.
sl@0:   **
sl@0:   ** We return -1000000 instead of the more usual -1 simply because using
sl@0:   ** -1000000 as incorrectly using -1000000 index into db->aDb[] is much 
sl@0:   ** more likely to cause a segfault than -1 (of course there are assert()
sl@0:   ** statements too, but it never hurts to play the odds).
sl@0:   */
sl@0:   assert( sqlite3_mutex_held(db->mutex) );
sl@0:   if( pSchema ){
sl@0:     for(i=0; i<db->nDb; i++){
sl@0:       if( db->aDb[i].pSchema==pSchema ){
sl@0:         break;
sl@0:       }
sl@0:     }
sl@0:     assert( i>=0 &&i>=0 &&  i<db->nDb );
sl@0:   }
sl@0:   return i;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Compile the UTF-8 encoded SQL statement zSql into a statement handle.
sl@0: */
sl@0: static int sqlite3Prepare(
sl@0:   sqlite3 *db,              /* Database handle. */
sl@0:   const char *zSql,         /* UTF-8 encoded SQL statement. */
sl@0:   int nBytes,               /* Length of zSql in bytes. */
sl@0:   int saveSqlFlag,          /* True to copy SQL text into the sqlite3_stmt */
sl@0:   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
sl@0:   const char **pzTail       /* OUT: End of parsed string */
sl@0: ){
sl@0:   Parse sParse;
sl@0:   char *zErrMsg = 0;
sl@0:   int rc = SQLITE_OK;
sl@0:   int i;
sl@0: 
sl@0:   assert( ppStmt );
sl@0:   *ppStmt = 0;
sl@0:   if( sqlite3SafetyOn(db) ){
sl@0:     return SQLITE_MISUSE;
sl@0:   }
sl@0:   assert( !db->mallocFailed );
sl@0:   assert( sqlite3_mutex_held(db->mutex) );
sl@0: 
sl@0:   /* If any attached database schemas are locked, do not proceed with
sl@0:   ** compilation. Instead return SQLITE_LOCKED immediately.
sl@0:   */
sl@0:   for(i=0; i<db->nDb; i++) {
sl@0:     Btree *pBt = db->aDb[i].pBt;
sl@0:     if( pBt ){
sl@0:       int rc;
sl@0:       rc = sqlite3BtreeSchemaLocked(pBt);
sl@0:       if( rc ){
sl@0:         const char *zDb = db->aDb[i].zName;
sl@0:         sqlite3Error(db, SQLITE_LOCKED, "database schema is locked: %s", zDb);
sl@0:         (void)sqlite3SafetyOff(db);
sl@0:         return sqlite3ApiExit(db, SQLITE_LOCKED);
sl@0:       }
sl@0:     }
sl@0:   }
sl@0:   
sl@0:   memset(&sParse, 0, sizeof(sParse));
sl@0:   sParse.db = db;
sl@0:   if( nBytes>=0 && (nBytes==0 || zSql[nBytes-1]!=0) ){
sl@0:     char *zSqlCopy;
sl@0:     int mxLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
sl@0:     if( nBytes>mxLen ){
sl@0:       sqlite3Error(db, SQLITE_TOOBIG, "statement too long");
sl@0:       (void)sqlite3SafetyOff(db);
sl@0:       return sqlite3ApiExit(db, SQLITE_TOOBIG);
sl@0:     }
sl@0:     zSqlCopy = sqlite3DbStrNDup(db, zSql, nBytes);
sl@0:     if( zSqlCopy ){
sl@0:       sqlite3RunParser(&sParse, zSqlCopy, &zErrMsg);
sl@0:       sqlite3DbFree(db, zSqlCopy);
sl@0:       sParse.zTail = &zSql[sParse.zTail-zSqlCopy];
sl@0:     }else{
sl@0:       sParse.zTail = &zSql[nBytes];
sl@0:     }
sl@0:   }else{
sl@0:     sqlite3RunParser(&sParse, zSql, &zErrMsg);
sl@0:   }
sl@0: 
sl@0:   if( db->mallocFailed ){
sl@0:     sParse.rc = SQLITE_NOMEM;
sl@0:   }
sl@0:   if( sParse.rc==SQLITE_DONE ) sParse.rc = SQLITE_OK;
sl@0:   if( sParse.checkSchema && !schemaIsValid(db) ){
sl@0:     sParse.rc = SQLITE_SCHEMA;
sl@0:   }
sl@0:   if( sParse.rc==SQLITE_SCHEMA ){
sl@0:     sqlite3ResetInternalSchema(db, 0);
sl@0:   }
sl@0:   if( db->mallocFailed ){
sl@0:     sParse.rc = SQLITE_NOMEM;
sl@0:   }
sl@0:   if( pzTail ){
sl@0:     *pzTail = sParse.zTail;
sl@0:   }
sl@0:   rc = sParse.rc;
sl@0: 
sl@0: #ifndef SQLITE_OMIT_EXPLAIN
sl@0:   if( rc==SQLITE_OK && sParse.pVdbe && sParse.explain ){
sl@0:     if( sParse.explain==2 ){
sl@0:       sqlite3VdbeSetNumCols(sParse.pVdbe, 3);
sl@0:       sqlite3VdbeSetColName(sParse.pVdbe, 0, COLNAME_NAME, "order", P4_STATIC);
sl@0:       sqlite3VdbeSetColName(sParse.pVdbe, 1, COLNAME_NAME, "from", P4_STATIC);
sl@0:       sqlite3VdbeSetColName(sParse.pVdbe, 2, COLNAME_NAME, "detail", P4_STATIC);
sl@0:     }else{
sl@0:       sqlite3VdbeSetNumCols(sParse.pVdbe, 8);
sl@0:       sqlite3VdbeSetColName(sParse.pVdbe, 0, COLNAME_NAME, "addr", P4_STATIC);
sl@0:       sqlite3VdbeSetColName(sParse.pVdbe, 1, COLNAME_NAME, "opcode", P4_STATIC);
sl@0:       sqlite3VdbeSetColName(sParse.pVdbe, 2, COLNAME_NAME, "p1", P4_STATIC);
sl@0:       sqlite3VdbeSetColName(sParse.pVdbe, 3, COLNAME_NAME, "p2", P4_STATIC);
sl@0:       sqlite3VdbeSetColName(sParse.pVdbe, 4, COLNAME_NAME, "p3", P4_STATIC);
sl@0:       sqlite3VdbeSetColName(sParse.pVdbe, 5, COLNAME_NAME, "p4", P4_STATIC);
sl@0:       sqlite3VdbeSetColName(sParse.pVdbe, 6, COLNAME_NAME, "p5", P4_STATIC);
sl@0:       sqlite3VdbeSetColName(sParse.pVdbe, 7, COLNAME_NAME, "comment",P4_STATIC);
sl@0:     }
sl@0:   }
sl@0: #endif
sl@0: 
sl@0:   if( sqlite3SafetyOff(db) ){
sl@0:     rc = SQLITE_MISUSE;
sl@0:   }
sl@0: 
sl@0:   if( saveSqlFlag ){
sl@0:     sqlite3VdbeSetSql(sParse.pVdbe, zSql, sParse.zTail - zSql);
sl@0:   }
sl@0:   if( rc!=SQLITE_OK || db->mallocFailed ){
sl@0:     sqlite3_finalize((sqlite3_stmt*)sParse.pVdbe);
sl@0:     assert(!(*ppStmt));
sl@0:   }else{
sl@0:     *ppStmt = (sqlite3_stmt*)sParse.pVdbe;
sl@0:   }
sl@0: 
sl@0:   if( zErrMsg ){
sl@0:     sqlite3Error(db, rc, "%s", zErrMsg);
sl@0:     sqlite3DbFree(db, zErrMsg);
sl@0:   }else{
sl@0:     sqlite3Error(db, rc, 0);
sl@0:   }
sl@0: 
sl@0:   rc = sqlite3ApiExit(db, rc);
sl@0:   assert( (rc&db->errMask)==rc );
sl@0:   return rc;
sl@0: }
sl@0: static int sqlite3LockAndPrepare(
sl@0:   sqlite3 *db,              /* Database handle. */
sl@0:   const char *zSql,         /* UTF-8 encoded SQL statement. */
sl@0:   int nBytes,               /* Length of zSql in bytes. */
sl@0:   int saveSqlFlag,          /* True to copy SQL text into the sqlite3_stmt */
sl@0:   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
sl@0:   const char **pzTail       /* OUT: End of parsed string */
sl@0: ){
sl@0:   int rc;
sl@0:   if( !sqlite3SafetyCheckOk(db) ){
sl@0:     return SQLITE_MISUSE;
sl@0:   }
sl@0:   sqlite3_mutex_enter(db->mutex);
sl@0:   sqlite3BtreeEnterAll(db);
sl@0:   rc = sqlite3Prepare(db, zSql, nBytes, saveSqlFlag, ppStmt, pzTail);
sl@0:   sqlite3BtreeLeaveAll(db);
sl@0:   sqlite3_mutex_leave(db->mutex);
sl@0:   return rc;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Rerun the compilation of a statement after a schema change.
sl@0: ** Return true if the statement was recompiled successfully.
sl@0: ** Return false if there is an error of some kind.
sl@0: */
sl@0: int sqlite3Reprepare(Vdbe *p){
sl@0:   int rc;
sl@0:   sqlite3_stmt *pNew;
sl@0:   const char *zSql;
sl@0:   sqlite3 *db;
sl@0: 
sl@0:   assert( sqlite3_mutex_held(sqlite3VdbeDb(p)->mutex) );
sl@0:   zSql = sqlite3_sql((sqlite3_stmt *)p);
sl@0:   assert( zSql!=0 );  /* Reprepare only called for prepare_v2() statements */
sl@0:   db = sqlite3VdbeDb(p);
sl@0:   assert( sqlite3_mutex_held(db->mutex) );
sl@0:   rc = sqlite3LockAndPrepare(db, zSql, -1, 0, &pNew, 0);
sl@0:   if( rc ){
sl@0:     if( rc==SQLITE_NOMEM ){
sl@0:       db->mallocFailed = 1;
sl@0:     }
sl@0:     assert( pNew==0 );
sl@0:     return 0;
sl@0:   }else{
sl@0:     assert( pNew!=0 );
sl@0:   }
sl@0:   sqlite3VdbeSwap((Vdbe*)pNew, p);
sl@0:   sqlite3TransferBindings(pNew, (sqlite3_stmt*)p);
sl@0:   sqlite3VdbeResetStepResult((Vdbe*)pNew);
sl@0:   sqlite3VdbeFinalize((Vdbe*)pNew);
sl@0:   return 1;
sl@0: }
sl@0: 
sl@0: 
sl@0: /*
sl@0: ** Two versions of the official API.  Legacy and new use.  In the legacy
sl@0: ** version, the original SQL text is not saved in the prepared statement
sl@0: ** and so if a schema change occurs, SQLITE_SCHEMA is returned by
sl@0: ** sqlite3_step().  In the new version, the original SQL text is retained
sl@0: ** and the statement is automatically recompiled if an schema change
sl@0: ** occurs.
sl@0: */
sl@0: SQLITE_EXPORT int sqlite3_prepare(
sl@0:   sqlite3 *db,              /* Database handle. */
sl@0:   const char *zSql,         /* UTF-8 encoded SQL statement. */
sl@0:   int nBytes,               /* Length of zSql in bytes. */
sl@0:   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
sl@0:   const char **pzTail       /* OUT: End of parsed string */
sl@0: ){
sl@0:   int rc;
sl@0:   rc = sqlite3LockAndPrepare(db,zSql,nBytes,0,ppStmt,pzTail);
sl@0:   assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
sl@0:   return rc;
sl@0: }
sl@0: SQLITE_EXPORT int sqlite3_prepare_v2(
sl@0:   sqlite3 *db,              /* Database handle. */
sl@0:   const char *zSql,         /* UTF-8 encoded SQL statement. */
sl@0:   int nBytes,               /* Length of zSql in bytes. */
sl@0:   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
sl@0:   const char **pzTail       /* OUT: End of parsed string */
sl@0: ){
sl@0:   int rc;
sl@0:   rc = sqlite3LockAndPrepare(db,zSql,nBytes,1,ppStmt,pzTail);
sl@0:   assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
sl@0:   return rc;
sl@0: }
sl@0: 
sl@0: 
sl@0: #ifndef SQLITE_OMIT_UTF16
sl@0: /*
sl@0: ** Compile the UTF-16 encoded SQL statement zSql into a statement handle.
sl@0: */
sl@0: static int sqlite3Prepare16(
sl@0:   sqlite3 *db,              /* Database handle. */ 
sl@0:   const void *zSql,         /* UTF-8 encoded SQL statement. */
sl@0:   int nBytes,               /* Length of zSql in bytes. */
sl@0:   int saveSqlFlag,          /* True to save SQL text into the sqlite3_stmt */
sl@0:   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
sl@0:   const void **pzTail       /* OUT: End of parsed string */
sl@0: ){
sl@0:   /* This function currently works by first transforming the UTF-16
sl@0:   ** encoded string to UTF-8, then invoking sqlite3_prepare(). The
sl@0:   ** tricky bit is figuring out the pointer to return in *pzTail.
sl@0:   */
sl@0:   char *zSql8;
sl@0:   const char *zTail8 = 0;
sl@0:   int rc = SQLITE_OK;
sl@0: 
sl@0:   if( !sqlite3SafetyCheckOk(db) ){
sl@0:     return SQLITE_MISUSE;
sl@0:   }
sl@0:   sqlite3_mutex_enter(db->mutex);
sl@0:   zSql8 = sqlite3Utf16to8(db, zSql, nBytes);
sl@0:   if( zSql8 ){
sl@0:     rc = sqlite3LockAndPrepare(db, zSql8, -1, saveSqlFlag, ppStmt, &zTail8);
sl@0:   }
sl@0: 
sl@0:   if( zTail8 && pzTail ){
sl@0:     /* If sqlite3_prepare returns a tail pointer, we calculate the
sl@0:     ** equivalent pointer into the UTF-16 string by counting the unicode
sl@0:     ** characters between zSql8 and zTail8, and then returning a pointer
sl@0:     ** the same number of characters into the UTF-16 string.
sl@0:     */
sl@0:     int chars_parsed = sqlite3Utf8CharLen(zSql8, zTail8-zSql8);
sl@0:     *pzTail = (u8 *)zSql + sqlite3Utf16ByteLen(zSql, chars_parsed);
sl@0:   }
sl@0:   sqlite3DbFree(db, zSql8); 
sl@0:   rc = sqlite3ApiExit(db, rc);
sl@0:   sqlite3_mutex_leave(db->mutex);
sl@0:   return rc;
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Two versions of the official API.  Legacy and new use.  In the legacy
sl@0: ** version, the original SQL text is not saved in the prepared statement
sl@0: ** and so if a schema change occurs, SQLITE_SCHEMA is returned by
sl@0: ** sqlite3_step().  In the new version, the original SQL text is retained
sl@0: ** and the statement is automatically recompiled if an schema change
sl@0: ** occurs.
sl@0: */
sl@0: SQLITE_EXPORT int sqlite3_prepare16(
sl@0:   sqlite3 *db,              /* Database handle. */ 
sl@0:   const void *zSql,         /* UTF-8 encoded SQL statement. */
sl@0:   int nBytes,               /* Length of zSql in bytes. */
sl@0:   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
sl@0:   const void **pzTail       /* OUT: End of parsed string */
sl@0: ){
sl@0:   int rc;
sl@0:   rc = sqlite3Prepare16(db,zSql,nBytes,0,ppStmt,pzTail);
sl@0:   assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
sl@0:   return rc;
sl@0: }
sl@0: SQLITE_EXPORT int sqlite3_prepare16_v2(
sl@0:   sqlite3 *db,              /* Database handle. */ 
sl@0:   const void *zSql,         /* UTF-8 encoded SQL statement. */
sl@0:   int nBytes,               /* Length of zSql in bytes. */
sl@0:   sqlite3_stmt **ppStmt,    /* OUT: A pointer to the prepared statement */
sl@0:   const void **pzTail       /* OUT: End of parsed string */
sl@0: ){
sl@0:   int rc;
sl@0:   rc = sqlite3Prepare16(db,zSql,nBytes,1,ppStmt,pzTail);
sl@0:   assert( rc==SQLITE_OK || ppStmt==0 || *ppStmt==0 );  /* VERIFY: F13021 */
sl@0:   return rc;
sl@0: }
sl@0: 
sl@0: #endif /* SQLITE_OMIT_UTF16 */