SQLite

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.529 2009/04/20 17:43:03 drh Exp $
*/
#include "sqliteInt.h"

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.
*/

      u32 mask;
      int iDb;
      sqlite3VdbeJumpHere(v, pParse->cookieGoto-1);
      for(iDb=0, mask=1; iDb<db->nDb; mask<<=1, iDb++){
        if( (mask & pParse->cookieMask)==0 ) continue;
        sqlite3VdbeUsesBtree(v, iDb);
        sqlite3VdbeAddOp2(v,OP_Transaction, iDb, (mask & pParse->writeMask)!=0);
        if( db->init.busy==0 ){
          sqlite3VdbeAddOp2(v,OP_VerifyCookie, iDb, pParse->cookieValue[iDb]);
        }
      }
#ifndef SQLITE_OMIT_VIRTUALTABLE
      {
        int i;
        for(i=0; i<pParse->nVtabLock; i++){
          char *vtab = (char *)pParse->apVtabLock[i]->pVtab;
          sqlite3VdbeAddOp4(v, OP_VBegin, 0, 0, 0, vtab, P4_VTAB);

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.582 2009/04/20 17:43:03 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/

**    PAGER_JOURNALMODE_QUERY
**    PAGER_JOURNALMODE_DELETE
**    PAGER_JOURNALMODE_TRUNCATE
**    PAGER_JOURNALMODE_PERSIST
**    PAGER_JOURNALMODE_OFF
**    PAGER_JOURNALMODE_MEMORY
**
** If the parameter is not _QUERY, then the journal_mode is set to the
** value specified if the change is allowed.  The change is disallowed
** for the following reasons:
**
**   *  An in-memory database can only have its journal_mode set to _OFF
**      or _MEMORY.

**
**   *  The journal mode may not be changed while a transaction is active.
**
** The returned indicate the current (possibly updated) journal-mode.
*/
int sqlite3PagerJournalMode(Pager *pPager, int eMode){
  assert( eMode==PAGER_JOURNALMODE_QUERY
            || eMode==PAGER_JOURNALMODE_DELETE
            || eMode==PAGER_JOURNALMODE_TRUNCATE
            || eMode==PAGER_JOURNALMODE_PERSIST
            || eMode==PAGER_JOURNALMODE_OFF 
            || eMode==PAGER_JOURNALMODE_MEMORY );
  assert( PAGER_JOURNALMODE_QUERY<0 );
  if( eMode>=0
   && (!MEMDB || eMode==PAGER_JOURNALMODE_MEMORY 
              || eMode==PAGER_JOURNALMODE_OFF)
   && !pPager->dbModified
  ){
    if( isOpen(pPager->jfd) ){
      sqlite3OsClose(pPager->jfd);
    }
    pPager->journalMode = (u8)eMode;
  }
  return (int)pPager->journalMode;
}

/*
** Get/set the size-limit used for persistent journal files.

**    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.c,v 1.117 2009/04/20 17:43:03 drh Exp $
*/
#include "sqliteInt.h"

/*
** Fill the InitData structure with an error message that indicates
** that the database is corrupt.
*/

** 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;
  int i;
  BtCursor *curMain;
  int size;
  Table *pTab;
  Db *pDb;
  char const *azArg[4];
  int meta[10];
  InitData initData;

  curMain = sqlite3MallocZero(sqlite3BtreeCursorSize());
  if( !curMain ){
    rc = SQLITE_NOMEM;
    goto error_out;
  }
  sqlite3BtreeEnter(pDb->pBt);
  rc = sqlite3BtreeCursor(pDb->pBt, MASTER_ROOT, 0, 0, curMain);
  if( rc==SQLITE_EMPTY ) rc = SQLITE_OK;
  if( rc!=SQLITE_OK ){
    sqlite3SetString(pzErrMsg, db, "%s", sqlite3ErrStr(rc));
    goto initone_error_out;
  }

  /* Get the database meta information.
  **
  ** Meta values are as follows:

  **    meta[7]
  **    meta[8]
  **    meta[9]
  **
  ** Note: The #defined SQLITE_UTF* symbols in sqliteInt.h correspond to
  ** the possible values of meta[4].
  */


  for(i=0; i<ArraySize(meta); i++){
    rc = sqlite3BtreeGetMeta(pDb->pBt, i+1, (u32 *)&meta[i]);
    if( rc ){
      sqlite3SetString(pzErrMsg, db, "%s", sqlite3ErrStr(rc));
      goto initone_error_out;
    }



  }
  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.

# 2008 April 17
#
# 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 implements regression tests for SQLite library. The focus
# of these tests is the journal mode pragma.
#
# $Id: jrnlmode.test,v 1.15 2009/04/20 17:43:03 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

ifcapable {!pager_pragmas} {
  finish_test
  return

      PRAGMA auto_vacuum = 1;
      CREATE TABLE abc(a, b, c);
    }
    execsql { PRAGMA page_count }
  } {3}

  do_test jrnlmode-4.2 {
breakpoint
    execsql { PRAGMA journal_mode = off }
  } {off}

  do_test jrnlmode-4.3 {
    execsql { INSERT INTO abc VALUES(1, 2, randomblob(2000)) }
  } {}

      execsql {
        PRAGMA journal_mode = truncate;
        CREATE TABLE t4(a, b);
        BEGIN;
          INSERT INTO t4 VALUES(1, 2);
          PRAGMA journal_mode = memory;
      }
    } {truncate truncate}
    do_test jrnlmode-6.2 {
      file exists test.db-journal
    } {1}
    do_test jrnlmode-6.3 {
      execsql {
        COMMIT;
        SELECT * FROM t4;
      }
    } {1 2}
    do_test jrnlmode-6.4 {
      file exists test.db-journal
    } {1}
    do_test jrnlmode-6.5 {
      execsql {
        PRAGMA journal_mode = MEMORY;
        BEGIN;
          INSERT INTO t4 VALUES(3, 4);
      }
      file exists test.db-journal
    } {1}
    do_test jrnlmode-6.7 {
      execsql {
        COMMIT;
        SELECT * FROM t4;
      }
    } {1 2 3 4}
    do_test jrnlmode-6.8 {
      file exists test.db-journal
    } {1}
    do_test jrnlmode-6.9 {
      execsql {
        PRAGMA journal_mode = DELETE;
        BEGIN IMMEDIATE; COMMIT;
      }
      file exists test.db-journal
    } {0}
  }
}

finish_test

# 2009 April 20
#
# 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.
#
#***********************************************************************
#
# Test cases inspired by ticket #3811.  Tests to make sure that
# the journal_mode can only be changed at appropriate times and that
# all reported changes are effective.
#
# $Id: jrnlmode3.test,v 1.5 2009/04/20 17:43:03 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

ifcapable {!pager_pragmas} {
  finish_test
  return
}


#
# Verify that journal_mode=OFF works as long as it occurs before the first
# transaction, even if locking_mode=EXCLUSIVE is enabled.  The behavior if
# journal_mode is changed after the first transaction is undefined and hence
# untested.
#
do_test jrnlmode3-1.1 {

    BEGIN;
    INSERT INTO t1 VALUES(2);
    ROLLBACK;
    SELECT * FROM t1;
  }
} {1 2}

# Test cases to verify that we can move from any journal_mode
# to any other, as long as we are not in a transaction.  Verify
# that we cannot change journal_mode while a transaction is active.
#
set all_journal_modes {delete persist truncate memory off}
set cnt 0
foreach fromjmode $all_journal_modes {
  foreach tojmode $all_journal_modes {

    # Skip the no-change cases
    if {$fromjmode==$tojmode} continue
    incr cnt

    # Start with a fresh database connection an empty database file.
    #
    db close
    file delete -force test.db test.db-journal
    sqlite3 db test.db

    # Initialize the journal mode.
    #
    do_test jrnlmode3-3.$cnt.1-($fromjmode-to-$tojmode) {
      db eval "PRAGMA journal_mode = $fromjmode;"
    } $fromjmode

    # Verify that the initial journal mode takes.
    #
    do_test jrnlmode3-3.$cnt.2 {
      db eval {PRAGMA main.journal_mode}
    } $fromjmode

    # Start a transaction and try to change the journal mode within
    # the transaction.  This should fail.
    #
    do_test jrnlmode3-3.$cnt.3 {
      db eval {
        CREATE TABLE t1(x);
        BEGIN;
        INSERT INTO t1 VALUES($cnt);
      }
      db eval "PRAGMA journal_mode=$tojmode"
    } $fromjmode

    # Rollback the transaction.  Verify that the rollback occurred
    # if journal_mode!=OFF.
    #
    do_test jrnlmode3-3.$cnt.4 {
      db eval {
        ROLLBACK;
        SELECT * FROM t1;
      }
    } [expr {$fromjmode=="off"?$cnt:""}]

    # Now change the journal mode again.  This time the new mode
    # should take.
    #
    do_test jrnlmode3-3.$cnt.5 {
      db eval "PRAGMA journal_mode=$tojmode"
    } $tojmode

    # Do a the transaction.  Verify that the rollback occurred
    # if journal_mode!=OFF.
    #
    do_test jrnlmode3-3.$cnt.6 {
      db eval {
        DROP TABLE IF EXISTS t1;
        CREATE TABLE t1(x);
        BEGIN;
        INSERT INTO t1 VALUES(1);
      }
      db eval ROLLBACK
      db eval {
        SELECT * FROM t1;
      }
    } [expr {$tojmode=="off"?"1":""}]
  }
}

finish_test