** 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 1.600 2009/06/20 18:52:50 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/
................................................................................
  if( rc!=SQLITE_OK ){
    return rc;
  }
  assert( pPager->state!=PAGER_UNLOCK );

  rc = sqlite3PcacheFetch(pPager->pPCache, pgno, 1, &pPg);
  if( rc!=SQLITE_OK ){

    return rc;
  }
  assert( pPg->pgno==pgno );
  assert( pPg->pPager==pPager || pPg->pPager==0 );
  if( pPg->pPager==0 ){
    /* The pager cache has created a new page. Its content needs to 
    ** be initialized.

** 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 1.601 2009/06/22 05:43:24 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"

/*
** Macros for troubleshooting.  Normally turned off
*/
................................................................................
  if( rc!=SQLITE_OK ){
    return rc;
  }
  assert( pPager->state!=PAGER_UNLOCK );

  rc = sqlite3PcacheFetch(pPager->pPCache, pgno, 1, &pPg);
  if( rc!=SQLITE_OK ){
    pagerUnlockIfUnused(pPager);
    return rc;
  }
  assert( pPg->pgno==pgno );
  assert( pPg->pPager==pPager || pPg->pPager==0 );
  if( pPg->pPager==0 ){
    /* The pager cache has created a new page. Its content needs to 
    ** be initialized.

# This file attempts to check the behavior of the SQLite library in 
# an out-of-memory situation. When compiled with -DSQLITE_DEBUG=1, 
# the SQLite library accepts a special command (sqlite3_memdebug_fail N C)
# which causes the N-th malloc to fail.  This special feature is used
# to see what happens in the library if a malloc were to really fail
# due to an out-of-memory situation.
#
# $Id: malloc.test,v 1.79 2009/06/06 16:08:23 danielk1977 Exp $

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


# Only run these tests if memory debugging is turned on.
#
................................................................................
do_malloc_test 36 -sqlprep {
  CREATE TABLE t1(a, b);
  INSERT INTO t1 VALUES(1, 2);
  INSERT INTO t1 VALUES(3, 4);
} -sqlbody {
  SELECT test_agg_errmsg16(), group_concat(a) FROM t1
}
























# Ensure that no file descriptors were leaked.
do_test malloc-99.X {
  catch {db close}
  set sqlite_open_file_count
} {0}

puts open-file-count=$sqlite_open_file_count
finish_test

# This file attempts to check the behavior of the SQLite library in 
# an out-of-memory situation. When compiled with -DSQLITE_DEBUG=1, 
# the SQLite library accepts a special command (sqlite3_memdebug_fail N C)
# which causes the N-th malloc to fail.  This special feature is used
# to see what happens in the library if a malloc were to really fail
# due to an out-of-memory situation.
#
# $Id: malloc.test,v 1.80 2009/06/22 05:43:24 danielk1977 Exp $

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


# Only run these tests if memory debugging is turned on.
#
................................................................................
do_malloc_test 36 -sqlprep {
  CREATE TABLE t1(a, b);
  INSERT INTO t1 VALUES(1, 2);
  INSERT INTO t1 VALUES(3, 4);
} -sqlbody {
  SELECT test_agg_errmsg16(), group_concat(a) FROM t1
}

# At one point, if an OOM occured immediately after obtaining a shared lock
# on the database file, the file remained locked. This test case ensures
# that bug has been fixed.
do_malloc_test 36 -tclprep {
  sqlite3 db2 test.db
  execsql {
    CREATE TABLE t1(a, b);
    INSERT INTO t1 VALUES(1, 2);
  } db2
} -sqlbody {
  SELECT * FROM t1;
} -cleanup {
  # Try to write to the database using connection [db2]. If connection [db]
  # has correctly released the shared lock, this write attempt should 
  # succeed. If [db] has not released the lock, this should hit an 
  # SQLITE_BUSY error.
  do_test malloc-36.$zRepeat.${::n}.unlocked {
    execsql {INSERT INTO t1 VALUES(3, 4)} db2
  } {}
  db2 close
}
catch { db2 close }

# Ensure that no file descriptors were leaked.
do_test malloc-99.X {
  catch {db close}
  set sqlite_open_file_count
} {0}

puts open-file-count=$sqlite_open_file_count
finish_test