# 2004 August 30
#
# 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.
#
# This file implements tests to make sure SQLite does not crash or
# segfault if it sees a corrupt database file.  It creates a base
# data base file, then tests that single byte corruptions in 
# increasingly larger quantities are handled gracefully.
#
# $Id: corruptC.test,v 1.1 2008/10/31 13:57:40 shane Exp $

catch {file delete -force test.db test.db-journal test.bu}

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

# Construct a compact, dense database for testing.
#
do_test corruptC-1.1 {
  execsql {
    BEGIN;
    CREATE TABLE t1(x);
    INSERT INTO t1 VALUES(1);
    INSERT OR IGNORE INTO t1 SELECT x*2 FROM t1;
    INSERT OR IGNORE INTO t1 SELECT x*3 FROM t1;
    INSERT OR IGNORE INTO t1 SELECT x*5 FROM t1;
    INSERT OR IGNORE INTO t1 SELECT x*7 FROM t1;
    INSERT OR IGNORE INTO t1 SELECT x*11 FROM t1;
    INSERT OR IGNORE INTO t1 SELECT x*13 FROM t1;
    CREATE INDEX t1i1 ON t1(x);
    CREATE TABLE t2 AS SELECT * FROM t1 WHERE rowid%5!=0;
    COMMIT;
  }
} {}

ifcapable {integrityck} {
  integrity_check corruptC-1.2
}

# Generate random integer
#
proc random {range} {
    return [expr {round(rand()*$range)}]
}

# Copy file $from into $to
#
proc copy_file {from to} {
  set f [open $from]
  fconfigure $f -translation binary
  set t [open $to w]
  fconfigure $t -translation binary
  puts -nonewline $t [read $f [file size $from]]
  close $t
  close $f
}

# Setup for the tests.  Make a backup copy of the good database in test.bu.
#
copy_file test.db test.bu
set fsize [file size test.db]

for {set tn 1} {$tn<=1024} {incr tn 1} {

  # setup for test
  db close
  copy_file test.bu test.db

  # Seek to a random location in the file, and write a random single byte
  # value.  Then do various operations on the file to make sure that
  # the database engine can handle the corruption gracefully.
  #
  set last 0
  for {set i 1} {$i<=1024 && !$last} {incr i 1} {

    # insert random byte at random location
    set fd [open test.db r+]
    fconfigure $fd -translation binary
    seek $fd [random $fsize]
    puts -nonewline $fd [format "%c" [expr [random 255]]]
    close $fd

    # do a few random operations to make sure that if 
    # they error, they error gracefully instead of crashing.
    do_test corruptC-2.$tn.$i.1 {
      sqlite3 db test.db
      catchsql {SELECT count(*) FROM sqlite_master}
      set x {}
    } {}
    do_test corruptC-2.$tn.$i.2 {
      catchsql {SELECT count(*) FROM t1}
      set x {}
    } {}
    do_test corruptC-2.$tn.$i.3 {
      catchsql {SELECT count(*) FROM t1 WHERE x>13}
      set x {}
    } {}
    do_test corruptC-2.$tn.$i.4 {
      catchsql {SELECT count(*) FROM t2}
      set x {}
    } {}
    do_test corruptC-2.$tn.$i.5 {
      catchsql {SELECT count(*) FROM t2 WHERE x<13}
      set x {}
    } {}

    # check the integrity of the database.
    # once the corruption is detected, we can stop.
    ifcapable {integrityck} {
      set res [ catchsql {PRAGMA integrity_check} ]
      set ans [lindex $res 1]
      if { [ string compare $ans "ok" ] != 0 } {
        set last -1
      }
    }
    # if we are not capable of doing an integrity check,
    # stop after corrupting 5 bytes.
    ifcapable {!integrityck} {
      if { $i > 5 } {
        set last -1
      }
    }

    # Check that no page references were leaked.
    do_test corruptC-2.$tn.$i.6 {
      set bt [btree_from_db db]
      db_enter db
      array set stats [btree_pager_stats $bt]
      db_leave db
      set stats(ref)
    } {0}

  }
  # end for i

}
# end for tn

finish_test