** 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.
**
*************************************************************************
** $Id: btree.c,v 1.454 2008/05/05 12:09:33 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

................................................................................
    **
    ** iSkip is the page number of the locking page (PENDING_BYTE_PAGE)
    ** in database *pTo (before the copy). This page is never written 
    ** into the journal file. Unless i==iSkip or the page was not
    ** present in pTo before the copy operation, journal page i from pTo.
    */
    if( i!=iSkip && i<=nToPage ){
      DbPage *pDbPage;
      rc = sqlite3PagerGet(pBtTo->pPager, i, &pDbPage);
      if( rc ){
        break;
      }
      rc = sqlite3PagerWrite(pDbPage);
      if( rc ){
        break;
      }
      if( i>nFromPage ){
        /* Yeah.  It seems wierd to call DontWrite() right after Write(). But
        ** that is because the names of those procedures do not exactly 
        ** represent what they do.  Write() really means "put this page in the
        ** rollback journal and mark it as dirty so that it will be written
        ** to the database file later."  DontWrite() undoes the second part of
        ** that and prevents the page from being written to the database. The
        ** page is still on the rollback journal, though.  And that is the 

** 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.
**
*************************************************************************
** $Id: btree.c,v 1.455 2008/05/05 15:26:51 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** See the header comment on "btreeInt.h" for additional information.
** Including a description of file format and an overview of operation.
*/
#include "btreeInt.h"

................................................................................
    **
    ** iSkip is the page number of the locking page (PENDING_BYTE_PAGE)
    ** in database *pTo (before the copy). This page is never written 
    ** into the journal file. Unless i==iSkip or the page was not
    ** present in pTo before the copy operation, journal page i from pTo.
    */
    if( i!=iSkip && i<=nToPage ){
      DbPage *pDbPage = 0;
      rc = sqlite3PagerGet(pBtTo->pPager, i, &pDbPage);
      if( rc==SQLITE_OK ){


        rc = sqlite3PagerWrite(pDbPage);


      }
      if( rc==SQLITE_OK && i>nFromPage ){
        /* Yeah.  It seems wierd to call DontWrite() right after Write(). But
        ** that is because the names of those procedures do not exactly 
        ** represent what they do.  Write() really means "put this page in the
        ** rollback journal and mark it as dirty so that it will be written
        ** to the database file later."  DontWrite() undoes the second part of
        ** that and prevents the page from being written to the database. The
        ** page is still on the rollback journal, though.  And that is the 

# This file implements regression tests for SQLite library.  The
# focus of this file is testing for correct handling of I/O errors
# such as writes failing because the disk is full.
# 
# The tests in this file use special facilities that are only
# available in the SQLite test fixture.
#
# $Id: ioerr.test,v 1.34 2008/01/16 17:46:38 drh Exp $

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


# If SQLITE_DEFAULT_AUTOVACUUM is set to true, then a simulated IO error
# on the 8th IO operation in the SQL script below doesn't report an error.
#
# This is because the 8th IO call attempts to read page 2 of the database
# file when the file on disk is only 1 page. The pager layer detects that
# this has happened and suppresses the error returned by the OS layer.
#
do_ioerr_test ioerr-1 -erc 1 -sqlprep {
  SELECT * FROM sqlite_master;
} -sqlbody {
  CREATE TABLE t1(a,b,c);
  SELECT * FROM sqlite_master;
  BEGIN TRANSACTION;
  INSERT INTO t1 VALUES(1,2,3);
  INSERT INTO t1 VALUES(4,5,6);
................................................................................
# the file-header of the temporary database used by VACUUM. Since the
# database doesn't exist at that point, the IO error is not detected.
# 
# Additionally, if auto-vacuum is enabled, the 12th IO error is not 
# detected. Same reason as the 8th in the test case above.
# 
ifcapable vacuum {
  do_ioerr_test ioerr-2 -cksum true -sqlprep { 
    BEGIN; 
    CREATE TABLE t1(a, b, c); 
    INSERT INTO t1 VALUES(1, randstr(50,50), randstr(50,50)); 
    INSERT INTO t1 SELECT a+2, b||'-'||rowid, c||'-'||rowid FROM t1; 
    INSERT INTO t1 SELECT a+4, b||'-'||rowid, c||'-'||rowid FROM t1;
    INSERT INTO t1 SELECT a+8, b||'-'||rowid, c||'-'||rowid FROM t1;
    INSERT INTO t1 SELECT a+16, b||'-'||rowid, c||'-'||rowid FROM t1;
................................................................................
    DROP TABLE t2;
  } -sqlbody {
    VACUUM;
  } -exclude [list \
      1 [expr [string match [execsql {pragma auto_vacuum}] 1]?9:-1]]
}

do_ioerr_test ioerr-3 -tclprep {
  execsql {
    PRAGMA cache_size = 10;
    BEGIN;
    CREATE TABLE abc(a);
    INSERT INTO abc VALUES(randstr(1500,1500)); -- Page 4 is overflow
  }
  for {set i 0} {$i<150} {incr i} {
................................................................................
  UPDATE abc SET a = randstr(90,90);
  COMMIT;
  CREATE TABLE abc3(a);
} 

# Test IO errors that can occur retrieving a record header that flows over
# onto an overflow page.
do_ioerr_test ioerr-4 -tclprep {
  set sql "CREATE TABLE abc(a1"
  for {set i 2} {$i<1300} {incr i} {
    append sql ", a$i"
  }
  append sql ");"
  execsql $sql
  execsql {INSERT INTO abc (a1) VALUES(NULL)}
................................................................................
# Tests 8 and 17 are excluded when auto-vacuum is enabled for the same 
# reason as in test cases ioerr-1.XXX
ifcapable attach {
  set ex ""
  if {[string match [execsql {pragma auto_vacuum}] 1]} {
    set ex [list 4 17]
  }
  do_ioerr_test ioerr-5 -sqlprep {
    ATTACH 'test2.db' AS test2;
  } -sqlbody {
    BEGIN;
    CREATE TABLE t1(a,b,c);
    CREATE TABLE test2.t2(a,b,c);
    COMMIT;
  } -exclude $ex
}

# Test IO errors when replaying two hot journals from a 2-file 
# transaction. This test only runs on UNIX.
ifcapable crashtest&&attach {
  if {![catch {sqlite3 -has_codec} r] && !$r} {
    do_ioerr_test ioerr-6 -tclprep {
      execsql {
        ATTACH 'test2.db' as aux;
        CREATE TABLE tx(a, b);
        CREATE TABLE aux.ty(a, b);
      }
      set rc [crashsql -delay 2 -file test2.db-journal {
        ATTACH 'test2.db' as aux;
................................................................................
  } -exclude 1
}

# For test coverage:  Cause an I/O failure while trying to read a
# short field (one that fits into a Mem buffer without mallocing
# for space).
#
do_ioerr_test ioerr-8 -tclprep {
  execsql {
    CREATE TABLE t1(a,b,c);
    INSERT INTO t1 VALUES(randstr(200,200), randstr(1000,1000), 2);
  }
  db close
  sqlite3 db test.db
} -sqlbody {
  SELECT c FROM t1;
}

# For test coverage: Cause an IO error whilst reading the master-journal
# name from a journal file.
if {$tcl_platform(platform)=="unix"} {
  do_ioerr_test ioerr-9 -tclprep {
    execsql {
      CREATE TABLE t1(a,b,c);
      INSERT INTO t1 VALUES(randstr(200,200), randstr(1000,1000), 2);
      BEGIN;
      INSERT INTO t1 VALUES(randstr(200,200), randstr(1000,1000), 2);
    }
    copy_file test.db-journal test2.db-journal
................................................................................
  } -sqlbody {
    SELECT a FROM t1;
  }
}

# For test coverage: Cause an IO error during statement playback (i.e. 
# a constraint).
do_ioerr_test ioerr-10 -tclprep {
  execsql {
    BEGIN;
    CREATE TABLE t1(a PRIMARY KEY, b);
  }
  for {set i 0} {$i < 500} {incr i} {
    execsql {INSERT INTO t1 VALUES(:i, 'hello world');}
  }
................................................................................
  if {$msg != "column a is not unique"} {
    error $msg
  }
}

# Assertion fault bug reported by alex dimitrov.
#
do_ioerr_test ioerr-11 -erc 1 -sqlprep {
   CREATE TABLE A(Id INTEGER, Name TEXT);
   INSERT INTO A(Id, Name) VALUES(1, 'Name');
} -sqlbody {
   UPDATE A SET Id = 2, Name = 'Name2' WHERE Id = 1;
}

# Test that an io error encountered in a sync() caused by a call to
# sqlite3_release_memory() is handled Ok. Only try this if 
# memory-management is enabled.
#
ifcapable memorymanage {
  do_ioerr_test memmanage-ioerr1 -sqlprep {
    BEGIN;
    CREATE TABLE t1(a, b, c);
    INSERT INTO t1 VALUES(randstr(50,50), randstr(100,100), randstr(10,10));
    INSERT INTO t1 SELECT randstr(50,50), randstr(9,9), randstr(90,90) FROM t1;
    INSERT INTO t1 SELECT randstr(50,50), randstr(9,9), randstr(90,90) FROM t1;
    INSERT INTO t1 SELECT randstr(50,50), randstr(9,9), randstr(90,90) FROM t1;
    INSERT INTO t1 SELECT randstr(50,50), randstr(9,9), randstr(90,90) FROM t1;

# This file implements regression tests for SQLite library.  The
# focus of this file is testing for correct handling of I/O errors
# such as writes failing because the disk is full.
# 
# The tests in this file use special facilities that are only
# available in the SQLite test fixture.
#
# $Id: ioerr.test,v 1.35 2008/05/05 15:26:51 danielk1977 Exp $

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


# If SQLITE_DEFAULT_AUTOVACUUM is set to true, then a simulated IO error
# on the 8th IO operation in the SQL script below doesn't report an error.
#
# This is because the 8th IO call attempts to read page 2 of the database
# file when the file on disk is only 1 page. The pager layer detects that
# this has happened and suppresses the error returned by the OS layer.
#
do_ioerr_test ioerr-1 -erc 1 -ckrefcount 1 -sqlprep {
  SELECT * FROM sqlite_master;
} -sqlbody {
  CREATE TABLE t1(a,b,c);
  SELECT * FROM sqlite_master;
  BEGIN TRANSACTION;
  INSERT INTO t1 VALUES(1,2,3);
  INSERT INTO t1 VALUES(4,5,6);
................................................................................
# the file-header of the temporary database used by VACUUM. Since the
# database doesn't exist at that point, the IO error is not detected.
# 
# Additionally, if auto-vacuum is enabled, the 12th IO error is not 
# detected. Same reason as the 8th in the test case above.
# 
ifcapable vacuum {
  do_ioerr_test ioerr-2 -cksum true -ckrefcount true -sqlprep { 
    BEGIN; 
    CREATE TABLE t1(a, b, c); 
    INSERT INTO t1 VALUES(1, randstr(50,50), randstr(50,50)); 
    INSERT INTO t1 SELECT a+2, b||'-'||rowid, c||'-'||rowid FROM t1; 
    INSERT INTO t1 SELECT a+4, b||'-'||rowid, c||'-'||rowid FROM t1;
    INSERT INTO t1 SELECT a+8, b||'-'||rowid, c||'-'||rowid FROM t1;
    INSERT INTO t1 SELECT a+16, b||'-'||rowid, c||'-'||rowid FROM t1;
................................................................................
    DROP TABLE t2;
  } -sqlbody {
    VACUUM;
  } -exclude [list \
      1 [expr [string match [execsql {pragma auto_vacuum}] 1]?9:-1]]
}

do_ioerr_test ioerr-3 -ckrefcount true -tclprep {
  execsql {
    PRAGMA cache_size = 10;
    BEGIN;
    CREATE TABLE abc(a);
    INSERT INTO abc VALUES(randstr(1500,1500)); -- Page 4 is overflow
  }
  for {set i 0} {$i<150} {incr i} {
................................................................................
  UPDATE abc SET a = randstr(90,90);
  COMMIT;
  CREATE TABLE abc3(a);
} 

# Test IO errors that can occur retrieving a record header that flows over
# onto an overflow page.
do_ioerr_test ioerr-4 -ckrefcount true -tclprep {
  set sql "CREATE TABLE abc(a1"
  for {set i 2} {$i<1300} {incr i} {
    append sql ", a$i"
  }
  append sql ");"
  execsql $sql
  execsql {INSERT INTO abc (a1) VALUES(NULL)}
................................................................................
# Tests 8 and 17 are excluded when auto-vacuum is enabled for the same 
# reason as in test cases ioerr-1.XXX
ifcapable attach {
  set ex ""
  if {[string match [execsql {pragma auto_vacuum}] 1]} {
    set ex [list 4 17]
  }
  do_ioerr_test ioerr-5 -ckrefcount true -sqlprep {
    ATTACH 'test2.db' AS test2;
  } -sqlbody {
    BEGIN;
    CREATE TABLE t1(a,b,c);
    CREATE TABLE test2.t2(a,b,c);
    COMMIT;
  } -exclude $ex
}

# Test IO errors when replaying two hot journals from a 2-file 
# transaction. This test only runs on UNIX.
ifcapable crashtest&&attach {
  if {![catch {sqlite3 -has_codec} r] && !$r} {
    do_ioerr_test ioerr-6 -ckrefcount true -tclprep {
      execsql {
        ATTACH 'test2.db' as aux;
        CREATE TABLE tx(a, b);
        CREATE TABLE aux.ty(a, b);
      }
      set rc [crashsql -delay 2 -file test2.db-journal {
        ATTACH 'test2.db' as aux;
................................................................................
  } -exclude 1
}

# For test coverage:  Cause an I/O failure while trying to read a
# short field (one that fits into a Mem buffer without mallocing
# for space).
#
do_ioerr_test ioerr-8 -ckrefcount true -tclprep {
  execsql {
    CREATE TABLE t1(a,b,c);
    INSERT INTO t1 VALUES(randstr(200,200), randstr(1000,1000), 2);
  }
  db close
  sqlite3 db test.db
} -sqlbody {
  SELECT c FROM t1;
}

# For test coverage: Cause an IO error whilst reading the master-journal
# name from a journal file.
if {$tcl_platform(platform)=="unix"} {
  do_ioerr_test ioerr-9 -ckrefcount true -tclprep {
    execsql {
      CREATE TABLE t1(a,b,c);
      INSERT INTO t1 VALUES(randstr(200,200), randstr(1000,1000), 2);
      BEGIN;
      INSERT INTO t1 VALUES(randstr(200,200), randstr(1000,1000), 2);
    }
    copy_file test.db-journal test2.db-journal
................................................................................
  } -sqlbody {
    SELECT a FROM t1;
  }
}

# For test coverage: Cause an IO error during statement playback (i.e. 
# a constraint).
do_ioerr_test ioerr-10 -ckrefcount true -tclprep {
  execsql {
    BEGIN;
    CREATE TABLE t1(a PRIMARY KEY, b);
  }
  for {set i 0} {$i < 500} {incr i} {
    execsql {INSERT INTO t1 VALUES(:i, 'hello world');}
  }
................................................................................
  if {$msg != "column a is not unique"} {
    error $msg
  }
}

# Assertion fault bug reported by alex dimitrov.
#
do_ioerr_test ioerr-11 -ckrefcount true -erc 1 -sqlprep {
   CREATE TABLE A(Id INTEGER, Name TEXT);
   INSERT INTO A(Id, Name) VALUES(1, 'Name');
} -sqlbody {
   UPDATE A SET Id = 2, Name = 'Name2' WHERE Id = 1;
}

# Test that an io error encountered in a sync() caused by a call to
# sqlite3_release_memory() is handled Ok. Only try this if 
# memory-management is enabled.
#
ifcapable memorymanage {
  do_ioerr_test memmanage-ioerr1 -ckrefcount true -sqlprep {
    BEGIN;
    CREATE TABLE t1(a, b, c);
    INSERT INTO t1 VALUES(randstr(50,50), randstr(100,100), randstr(10,10));
    INSERT INTO t1 SELECT randstr(50,50), randstr(9,9), randstr(90,90) FROM t1;
    INSERT INTO t1 SELECT randstr(50,50), randstr(9,9), randstr(90,90) FROM t1;
    INSERT INTO t1 SELECT randstr(50,50), randstr(9,9), randstr(90,90) FROM t1;
    INSERT INTO t1 SELECT randstr(50,50), randstr(9,9), randstr(90,90) FROM t1;

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements some common TCL routines used for regression
# testing the SQLite library
#
# $Id: tester.tcl,v 1.116 2008/04/17 19:14:02 drh Exp $

#
# What for user input before continuing.  This gives an opportunity
# to connect profiling tools to the process.
#
for {set i 0} {$i<[llength $argv]} {incr i} {
  if {[regexp {^-+pause$} [lindex $argv $i] all value]} {
................................................................................
proc do_ioerr_test {testname args} {

  set ::ioerropts(-start) 1
  set ::ioerropts(-cksum) 0
  set ::ioerropts(-erc) 0
  set ::ioerropts(-count) 100000000
  set ::ioerropts(-persist) 1

  array set ::ioerropts $args

  set ::go 1
  #reset_prng_state
  save_prng_state
  for {set n $::ioerropts(-start)} {$::go} {incr n} {
    set ::TN $n
................................................................................

      # One of two things must have happened. either
      #   1.  We never hit the IO error and the SQL returned OK
      #   2.  An IO error was hit and the SQL failed
      #
      expr { ($s && !$r && !$q) || (!$s && $r && $q) }
    } {1}














    # If an IO error occured, then the checksum of the database should
    # be the same as before the script that caused the IO error was run.
    if {$::go && $::sqlite_io_error_hardhit && $::ioerropts(-cksum)} {
      do_test $testname.$n.4 {
        catch {db close}
        set ::DB [sqlite3 db test.db; sqlite3_connection_pointer db]
        cksum
      } $checksum
    }

    set ::sqlite_io_error_hardhit 0

#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements some common TCL routines used for regression
# testing the SQLite library
#
# $Id: tester.tcl,v 1.117 2008/05/05 15:26:51 danielk1977 Exp $

#
# What for user input before continuing.  This gives an opportunity
# to connect profiling tools to the process.
#
for {set i 0} {$i<[llength $argv]} {incr i} {
  if {[regexp {^-+pause$} [lindex $argv $i] all value]} {
................................................................................
proc do_ioerr_test {testname args} {

  set ::ioerropts(-start) 1
  set ::ioerropts(-cksum) 0
  set ::ioerropts(-erc) 0
  set ::ioerropts(-count) 100000000
  set ::ioerropts(-persist) 1
  set ::ioerropts(-ckrefcount) 0
  array set ::ioerropts $args

  set ::go 1
  #reset_prng_state
  save_prng_state
  for {set n $::ioerropts(-start)} {$::go} {incr n} {
    set ::TN $n
................................................................................

      # One of two things must have happened. either
      #   1.  We never hit the IO error and the SQL returned OK
      #   2.  An IO error was hit and the SQL failed
      #
      expr { ($s && !$r && !$q) || (!$s && $r && $q) }
    } {1}

    if {$::go && $::sqlite_io_error_hardhit && $::ioerropts(-ckrefcount)} {
      # Check that no page references were leaked. There should be 
      # a single reference if there is still an active transaction, 
      # or zero otherwise.
      do_test $testname.$n.4 {
        set bt [btree_from_db db]
        db_enter db
        array set stats [btree_pager_stats $bt]
        db_leave db
        set stats(ref)
      } [expr {[sqlite3_get_autocommit db]?0:1}]
    }

    # If an IO error occured, then the checksum of the database should
    # be the same as before the script that caused the IO error was run.
    if {$::go && $::sqlite_io_error_hardhit && $::ioerropts(-cksum)} {
      do_test $testname.$n.5 {
        catch {db close}
        set ::DB [sqlite3 db test.db; sqlite3_connection_pointer db]
        cksum
      } $checksum
    }

    set ::sqlite_io_error_hardhit 0