SQLite

** exist it is created by this call.
**
** A SHARED lock should be held on the database file when this function
** is called. The purpose of this SHARED lock is to prevent any other
** client from unlinking the log or wal-index file. If another process
** were to do this just after this client opened one of these files, the
** system would be badly broken.
**
** If the log file is successfully opened, SQLITE_OK is returned and 
** *ppWal is set to point to a new WAL handle. If an error occurs,
** an SQLite error code is returned and *ppWal is left unmodified.
*/
int sqlite3WalOpen(
  sqlite3_vfs *pVfs,              /* vfs module to open wal and wal-index */
  const char *zDb,                /* Name of database file */
  Wal **ppWal                     /* OUT: Allocated Wal handle */
){
  int rc;                         /* Return Code */
  Wal *pRet;                      /* Object to allocate and return */
  int flags;                      /* Flags passed to OsOpen() */
  char *zWal;                     /* Path to WAL file */
  int nWal;                       /* Length of zWal in bytes */

  assert( zDb );
  if( pVfs->xShmOpen==0 ) return SQLITE_CANTOPEN_BKPT;

  /* Allocate an instance of struct Wal to return. */
  *ppWal = 0;

  /* Open file handle on the write-ahead log file. */
  if( rc==SQLITE_OK ){
    flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_MAIN_JOURNAL);
    rc = sqlite3OsOpen(pVfs, zWal, pRet->pFd, flags, &flags);
  }

  if( rc!=SQLITE_OK ){

    pVfs->xShmClose(pVfs, pRet->pWIndex, 0);
    sqlite3OsClose(pRet->pFd);
    sqlite3_free(pRet);
  }else{
    *ppWal = pRet;
  }

  return rc;
}

static int walIteratorNext(
  WalIterator *p,               /* Iterator */
  u32 *piPage,                  /* OUT: Next db page to write */
  u32 *piFrame                  /* OUT: Wal frame to read from */

      }
    }
  }
}

##########################################################################

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

# If this build does not include FTS3, skip the tests in this file.
#
ifcapable !fts3 { finish_test ; return }
source $testdir/malloc_common.tcl
source $testdir/fts3_common.tcl
set DO_MALLOC_TEST 0

do_test fts3query-1.1 {
  execsql {
    CREATE VIRTUAL TABLE t1 USING fts3(x);
    BEGIN;

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

# If this build does not include FTS3, skip the tests in this file.
#
ifcapable !fts3 { finish_test ; return }
source $testdir/fts3_common.tcl
source $testdir/malloc_common.tcl

set G(nVocab) 100

set nVocab 100
set lVocab [list]

expr srand(0)

        catch [list uplevel #0 $::mallocopts(-cleanup)] msg
      }
    }
  }
  unset ::mallocopts
  sqlite3_memdebug_fail -1
}


#-------------------------------------------------------------------------
# This proc is used to test a single SELECT statement. Parameter $name is
# passed a name for the test case (i.e. "fts3_malloc-1.4.1") and parameter
# $sql is passed the text of the SELECT statement. Parameter $result is
# set to the expected output if the SELECT statement is successfully
# executed using [db eval].
#
# Example:
#
#   do_select_test testcase-1.1 "SELECT 1+1, 1+2" {1 2}
#
# If global variable DO_MALLOC_TEST is set to a non-zero value, or if
# it is not defined at all, then OOM testing is performed on the SELECT
# statement. Each OOM test case is said to pass if either (a) executing
# the SELECT statement succeeds and the results match those specified
# by parameter $result, or (b) TCL throws an "out of memory" error.
#
# If DO_MALLOC_TEST is defined and set to zero, then the SELECT statement
# is executed just once. In this case the test case passes if the results
# match the expected results passed via parameter $result.
#
proc do_select_test {name sql result} {
  uplevel [list doPassiveTest 0 $name $sql [list 0 $result]]
}

proc do_restart_select_test {name sql result} {
  uplevel [list doPassiveTest 1 $name $sql [list 0 $result]]
}

proc do_error_test {name sql error} {
  uplevel [list doPassiveTest 0 $name $sql [list 1 $error]]
}

proc doPassiveTest {isRestart name sql catchres} {
  if {![info exists ::DO_MALLOC_TEST]} { set ::DO_MALLOC_TEST 1 }

  switch $::DO_MALLOC_TEST {
    0 { # No malloc failures.
      do_test $name [list set {} [uplevel [list catchsql $sql]]] $catchres
      return
    }
    1 { # Simulate transient failures.
      set nRepeat 1
      set zName "transient"
      set nStartLimit 100000
      set nBackup 1
    }
    2 { # Simulate persistent failures.
      set nRepeat 1
      set zName "persistent"
      set nStartLimit 100000
      set nBackup 1
    }
    3 { # Simulate transient failures with extra brute force.
      set nRepeat 100000
      set zName "ridiculous"
      set nStartLimit 1
      set nBackup 10
    }
  }

  # The set of acceptable results from running [catchsql $sql].
  #
  set answers [list {1 {out of memory}} $catchres]
  set str [join $answers " OR "]

  set nFail 1
  for {set iLimit $nStartLimit} {$nFail} {incr iLimit} {
    for {set iFail 1} {$nFail && $iFail<=$iLimit} {incr iFail} {
      for {set iTest 0} {$iTest<$nBackup && ($iFail-$iTest)>0} {incr iTest} {

        if {$isRestart} { sqlite3 db test.db }

        sqlite3_memdebug_fail [expr $iFail-$iTest] -repeat $nRepeat
        set res [uplevel [list catchsql $sql]]
        if {[lsearch -exact $answers $res]>=0} { set res $str }
        set testname "$name.$zName.$iFail"
        do_test "$name.$zName.$iLimit.$iFail" [list set {} $res] $str

        set nFail [sqlite3_memdebug_fail -1 -benigncnt nBenign]
      }
    }
  }
}


#-------------------------------------------------------------------------
# Test a single write to the database. In this case a  "write" is a 
# DELETE, UPDATE or INSERT statement.
#
# If OOM testing is performed, there are several acceptable outcomes:
#
#   1) The write succeeds. No error is returned.
#
#   2) An "out of memory" exception is thrown and:
#
#     a) The statement has no effect, OR
#     b) The current transaction is rolled back, OR
#     c) The statement succeeds. This can only happen if the connection
#        is in auto-commit mode (after the statement is executed, so this
#        includes COMMIT statements).
#
# If the write operation eventually succeeds, zero is returned. If a
# transaction is rolled back, non-zero is returned.
#
# Parameter $name is the name to use for the test case (or test cases).
# The second parameter, $tbl, should be the name of the database table
# being modified. Parameter $sql contains the SQL statement to test.
#
proc do_write_test {name tbl sql} {
  if {![info exists ::DO_MALLOC_TEST]} { set ::DO_MALLOC_TEST 1 }

  # Figure out an statement to get a checksum for table $tbl.
  db eval "SELECT * FROM $tbl" V break
  set cksumsql "SELECT md5sum([join [concat rowid $V(*)] ,]) FROM $tbl"

  # Calculate the initial table checksum.
  set cksum1 [db one $cksumsql]

  if {$::DO_MALLOC_TEST } {
    set answers [list {1 {out of memory}} {0 {}}]
    if {$::DO_MALLOC_TEST==1} {
      set modes {100000 transient}
    } else {
      set modes {1 persistent}
    }
  } else {
    set answers [list {0 {}}]
    set modes [list 0 nofail]
  }
  set str [join $answers " OR "]

  foreach {nRepeat zName} $modes {
    for {set iFail 1} 1 {incr iFail} {
      if {$::DO_MALLOC_TEST} {sqlite3_memdebug_fail $iFail -repeat $nRepeat}

      set res [uplevel [list catchsql $sql]]
      set nFail [sqlite3_memdebug_fail -1 -benigncnt nBenign]
      if {$nFail==0} {
        do_test $name.$zName.$iFail [list set {} $res] {0 {}}
        return
      } else {
        if {[lsearch $answers $res]>=0} {
          set res $str
        }
        do_test $name.$zName.$iFail [list set {} $res] $str
        set cksum2 [db one $cksumsql]
        if {$cksum1 != $cksum2} return
      }
    }
  }
}

ifcapable !wal {finish_test ; return }

do_malloc_test walfault-oom-1 -sqlbody {
  PRAGMA journal_mode = WAL;
  CREATE TABLE t1(a, b);
  INSERT INTO t1 VALUES(1, 2);
  PRAGMA wal_checkpoint;
}

do_malloc_test walfault-oom-2 -tclprep {
  execsql {
    PRAGMA journal_mode = WAL;
    BEGIN;
      CREATE TABLE x(y, z, UNIQUE(y, z));