SQLite

** 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 1.444 2008/05/09 16:57:51 danielk1977 Exp $
** @(#) $Id: pager.c,v 1.445 2008/05/13 00:58:18 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include <assert.h>
#include <string.h>

/*

  u8 dirtyCache;              /* True if cached pages have changed */
  u8 alwaysRollback;          /* Disable DontRollback() for all pages */
  u8 memDb;                   /* True to inhibit all file I/O */
  u8 setMaster;               /* True if a m-j name has been written to jrnl */
  u8 doNotSync;               /* Boolean. While true, do not spill the cache */
  u8 exclusiveMode;           /* Boolean. True if locking_mode==EXCLUSIVE */
  u8 journalMode;             /* On of the PAGER_JOURNALMODE_* values */
  u8 dbModified;              /* True if there are any changes to the Db */
  u8 changeCountDone;         /* Set after incrementing the change-counter */
  u32 vfsFlags;               /* Flags for sqlite3_vfs.xOpen() */
  int errCode;                /* One of several kinds of errors */
  int dbSize;                 /* Number of pages in the file */
  int origDbSize;             /* dbSize before the current change */
  int stmtSize;               /* Size of database (in pages) at stmt_begin() */
  int nRec;                   /* Number of pages written to the journal */

    pPager->state = PAGER_EXCLUSIVE;
  }
  pPager->origDbSize = 0;
  pPager->setMaster = 0;
  pPager->needSync = 0;
  lruListSetFirstSynced(pPager);
  pPager->dbSize = -1;
  pPager->dbModified = 0;

  return (rc==SQLITE_OK?rc2:rc);
}

/*
** Compute and return a checksum for the page of data.
**

      PAGERTRACE2("TRANSACTION %d\n", PAGERID(pPager));
      if( pPager->useJournal && !pPager->tempFile
             && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
        rc = pager_open_journal(pPager);
      }
    }
  }else if( pPager->journalOpen && pPager->journalOff==0 ){
    /* This happens when the pager was in exclusive-access mode last
    /* This happens when the pager was in exclusive-access mode the last
    ** time a (read or write) transaction was successfully concluded
    ** by this connection. Instead of deleting the journal file it was 
    ** kept open and truncated to 0 bytes.
    ** kept open and either was truncated to 0 bytes or its header was
    ** overwritten with zeros.
    */
    assert( pPager->nRec==0 );
    assert( pPager->origDbSize==0 );
    assert( pPager->pInJournal==0 );
    sqlite3PagerPagecount(pPager);
    pagerLeave(pPager);
    pPager->pInJournal = sqlite3BitvecCreate( pPager->dbSize );

  /* Mark the page as dirty.  If the page has already been written
  ** to the journal then we can return right away.
  */
  makeDirty(pPg);
  if( pPg->inJournal && (pageInStatement(pPg) || pPager->stmtInUse==0) ){
    pPager->dirtyCache = 1;
    pPager->dbModified = 1;
  }else{

    /* If we get this far, it means that the page needs to be
    ** written to the transaction journal or the ckeckpoint journal
    ** or both.
    **
    ** First check to see that the transaction journal exists and

    assert( pPager->state>=PAGER_RESERVED );
    if( !pPager->journalOpen && pPager->useJournal
          && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
      rc = pager_open_journal(pPager);
      if( rc!=SQLITE_OK ) return rc;
    }
    pPager->dirtyCache = 1;
    pPager->dbModified = 1;
  
    /* The transaction journal now exists and we have a RESERVED or an
    ** EXCLUSIVE lock on the main database file.  Write the current page to
    ** the transaction journal if it is not there already.
    */
    if( !pPg->inJournal && (pPager->journalOpen || MEMDB) ){
      if( (int)pPg->pgno <= pPager->origDbSize ){

int sqlite3PagerCommitPhaseOne(
  Pager *pPager, 
  const char *zMaster, 
  Pgno nTrunc,
  int noSync
){
  int rc = SQLITE_OK;

  /* If no changes have been made, we can leave the transaction early.
  */
  if( pPager->dbModified==0 &&
        (pPager->journalMode!=PAGER_JOURNALMODE_DELETE ||
          pPager->exclusiveMode!=0) ){
    assert( pPager->dirtyCache==0 || pPager->journalOpen==0 );
    return SQLITE_OK;
  }

  PAGERTRACE4("DATABASE SYNC: File=%s zMaster=%s nTrunc=%d\n", 
      pPager->zFilename, zMaster, nTrunc);
  pagerEnter(pPager);

  /* If this is an in-memory db, or no pages have been written to, or this
  ** function has already been called, it is a no-op.

  PgHdr *pPg;

  if( pPager->errCode ){
    return pPager->errCode;
  }
  if( pPager->state<PAGER_RESERVED ){
    return SQLITE_ERROR;
  }
  if( pPager->dbModified==0 &&
        (pPager->journalMode!=PAGER_JOURNALMODE_DELETE ||
          pPager->exclusiveMode!=0) ){
    assert( pPager->dirtyCache==0 || pPager->journalOpen==0 );
    return SQLITE_OK;
  }
  pagerEnter(pPager);
  PAGERTRACE2("COMMIT %d\n", PAGERID(pPager));
  if( MEMDB ){
    pPg = pager_get_all_dirty_pages(pPager);
    while( pPg ){
      PgHistory *pHist = PGHDR_TO_HIST(pPg, pPager);

  }
  pPg->pNextHash = pPager->aHash[h];
  pPager->aHash[h] = pPg;
  pPg->pPrevHash = 0;

  makeDirty(pPg);
  pPager->dirtyCache = 1;
  pPager->dbModified = 1;

  if( needSyncPgno ){
    /* If needSyncPgno is non-zero, then the journal file needs to be 
    ** sync()ed before any data is written to database file page needSyncPgno.
    ** Currently, no such page exists in the page-cache and the 
    ** Pager.pInJournal bit has been set. This needs to be remedied by loading
    ** the page into the pager-cache and setting the PgHdr.needSync flag.

#
#***********************************************************************
#
# This file contains tests to ensure that the library handles malloc() failures
# correctly. The emphasis of these tests are the _prepare(), _step() and
# _finalize() calls.
#
# $Id: malloc3.test,v 1.20 2008/02/18 22:24:58 drh Exp $
# $Id: malloc3.test,v 1.21 2008/05/13 00:58:18 drh Exp $

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

# Only run these tests if memory debugging is turned on.
#

        incr pc
      }

      -sql {
        set ::rollback_hook_count 0

        set ac [sqlite3_get_autocommit $::DB]        ;# Auto-Commit
if {$iterid=="pc=4.iFail=44-sql"} breakpoint
        sqlite3_memdebug_fail $iFail -repeat 0
#puts sql=[lindex $v 1]
        set rc [catch {db eval [lindex $v 1]} msg]   ;# True error occurs
#puts "rc=$rc msg=$msg"
        set nac [sqlite3_get_autocommit $::DB]       ;# New Auto-Commit 

        if {$rc != 0 && $nac && !$ac} {
          # Before [db eval] the auto-commit flag was clear. Now it
          # is set. Since an error occured we assume this was not a
	  # commit - therefore a rollback occured. Check that the
	  # rollback-hook was invoked.
          do_test malloc3-rollback_hook.$iterid {
            set ::rollback_hook_count
          } {1}
        }

        set nFail [sqlite3_memdebug_fail -1 -benigncnt nBenign]
        if {$rc == 0} {
            # Successful execution of sql. The number of failed malloc()
            # calls should be equal to the number of benign failures.
            # Otherwise a malloc() failed and the error was not reported.
            # 
            if {$nFail!=$nBenign} {
              error "Unreported malloc() failure"
#              error "Unreported malloc() failure"
            }

            if {$ac && !$nac} {
              # Before the [db eval] the auto-commit flag was set, now it
              # is clear. We can deduce that a "BEGIN" statement has just
              # been successfully executed.
              set begin_pc $pc