# 2001 September 15

 #

 # 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.  The

 # focus of this script is database locks between competing processes.

 #

 # $Id: lock2.test,v 1.9 2007/12/13 21:54:11 drh Exp $

 set testdir [file dirname $argv0]

 source $testdir/tester.tcl

 # Launch another testfixture process to be controlled by this one. A

 # channel name is returned that may be passed as the first argument to proc

 # 'testfixture' to execute a command. The child testfixture process is shut

 # down by closing the channel.

 proc launch_testfixture {} {

   set prg [info nameofexec]

   if {$prg eq ""} {

     set prg [file join . testfixture]

   }

   set chan [open "|$prg tf_main.tcl" r+]

   fconfigure $chan -buffering line

   return $chan

 }

 # Execute a command in a child testfixture process, connected by two-way

 # channel $chan. Return the result of the command, or an error message.

 proc testfixture {chan cmd} {

   puts $chan $cmd

   puts $chan OVER

   set r ""

   while { 1 } {

     set line [gets $chan]

     if { $line == "OVER" } { 

       return $r

     }

     append r $line

   }

 }

 # Write the main loop for the child testfixture processes into file

 # tf_main.tcl. The parent (this script) interacts with the child processes

 # via a two way pipe. The parent writes a script to the stdin of the child

 # process, followed by the word "OVER" on a line of its own. The child

 # process evaluates the script and writes the results to stdout, followed

 # by an "OVER" of its own.

 set f [open tf_main.tcl w]

 puts $f {

   set l [open log w]

   set script ""

   while {![eof stdin]} {

     flush stdout

     set line [gets stdin]

     puts $l "READ $line"

     if { $line == "OVER" } {

       catch {eval $script} result

       puts $result

       puts $l "WRITE $result"

       puts OVER

       puts $l "WRITE OVER"

       flush stdout

       set script ""

     } else {

       append script $line

       append script " ; "

     }

   }

   close $l

 }

 close $f

 # Simple locking test case:

 #

 # lock2-1.1: Connect a second process to the database.

 # lock2-1.2: Establish a RESERVED lock with this process.

 # lock2-1.3: Get a SHARED lock with the second process.

 # lock2-1.4: Try for a RESERVED lock with process 2. This fails.

 # lock2-1.5: Try to upgrade the first process to EXCLUSIVE, this fails so

 #            it gets PENDING.

 # lock2-1.6: Release the SHARED lock held by the second process. 

 # lock2-1.7: Attempt to reaquire a SHARED lock with the second process.

 #            this fails due to the PENDING lock.

 # lock2-1.8: Ensure the first process can now upgrade to EXCLUSIVE.

 #

 do_test lock2-1.1 {

   set ::tf1 [launch_testfixture]

   testfixture $::tf1 "set sqlite_pending_byte $::sqlite_pending_byte"

   testfixture $::tf1 {

     sqlite3 db test.db -key xyzzy

     db eval {select * from sqlite_master}

   }

 } {}

 do_test lock2-1.1.1 {

   execsql {pragma lock_status}

 } {main unlocked temp closed}

 sqlite3_soft_heap_limit 0

 do_test lock2-1.2 {

   execsql {

     BEGIN;

     CREATE TABLE abc(a, b, c);

   }

 } {}

 do_test lock2-1.3 {

   testfixture $::tf1 {

     db eval {

       BEGIN;

       SELECT * FROM sqlite_master;

     }

   }

 } {}

 do_test lock2-1.4 {

   testfixture $::tf1 {

     db eval {

       CREATE TABLE def(d, e, f)

     }

   }

 } {database is locked}

 do_test lock2-1.5 {

   catchsql {

     COMMIT;

   }

 } {1 {database is locked}}

 do_test lock2-1.6 {

   testfixture $::tf1 {

     db eval {

       SELECT * FROM sqlite_master;

       COMMIT;

     }

   }

 } {}

 do_test lock2-1.7 {

   testfixture $::tf1 {

     db eval {

       BEGIN;

       SELECT * FROM sqlite_master;

     }

   }

 } {database is locked}

 do_test lock2-1.8 {

   catchsql {

     COMMIT;

   }

 } {0 {}}

 do_test lock2-1.9 {

   execsql {

     SELECT * FROM sqlite_master;

   }

 } "table abc abc [expr $AUTOVACUUM?3:2] {CREATE TABLE abc(a, b, c)}"

 do_test lock2-1.10 {

   testfixture $::tf1 {

     db eval {

       SELECT * FROM sqlite_master;

     }

   }

 } "table abc abc [expr $AUTOVACUUM?3:2] {CREATE TABLE abc(a, b, c)}"

 catch {testfixture $::tf1 {db close}}

 catch {close $::tf1}

 sqlite3_soft_heap_limit $soft_limit

 finish_test