# 2007 April 6

 #

 # 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.

 #

 # $Id: lock4.test,v 1.8 2008/03/14 08:57:42 danielk1977 Exp $

 set testdir [file dirname $argv0]

 source $testdir/tester.tcl

 # Initialize the test.db database so that it is non-empty

 #

 do_test lock4-1.1 {

   db eval {

      PRAGMA auto_vacuum=OFF;

      CREATE TABLE t1(x);

   }

   file delete -force test2.db test2.db-journal

   sqlite3 db2 test2.db

   db2 eval {

      PRAGMA auto_vacuum=OFF;

      CREATE TABLE t2(x)

   }

   db2 close

   list [file size test.db] [file size test2.db]

 } {2048 2048}

 # Create a script to drive a separate process that will

 #

 #     1.  Create a second database test2.db

 #     2.  Get an exclusive lock on test2.db

 #     3.  Add an entry to test.db in table t1, waiting as necessary.

 #     4.  Commit the change to test2.db.

 #

 # Meanwhile, this process will:

 # 

 #     A.  Get an exclusive lock on test.db

 #     B.  Attempt to read from test2.db but get an SQLITE_BUSY error.

 #     C.  Commit the changes to test.db thus alloing the other process

 #         to continue.

 #

 do_test lock4-1.2 {

   # Create a script for the second process to run.

   #

   set out [open test2-script.tcl w]

   puts $out "set sqlite_pending_byte [set sqlite_pending_byte]"

   puts $out {

      sqlite3 db2 test2.db

      db2 eval {

         BEGIN;

         INSERT INTO t2 VALUES(2);

      }

      sqlite3 db test.db

      db timeout 1000000

      db eval {

         INSERT INTO t1 VALUES(2);

      }

      db close

      db2 eval COMMIT

      exit

   }

   close $out

   # Begin a transaction on test.db.

   db eval {

      BEGIN EXCLUSIVE;

      INSERT INTO t1 VALUES(1);

   }

   # Kick off the second process.

   exec [info nameofexec] ./test2-script.tcl &

   # Wait until the second process has started its transaction on test2.db.

   while {![file exists test2.db-journal]} {

     after 10

   }

   # Try to write to test2.db. We are locked out.

   sqlite3 db2 test2.db

   catchsql {

     INSERT INTO t2 VALUES(1)

   } db2

 } {1 {database is locked}}

 do_test lock4-1.3 {

   db eval {

      COMMIT;

   }

   while {[file exists test2.db-journal]} {

     after 10

   }

   # The other process has committed its transaction on test2.db by 

   # deleting the journal file. But it might retain the lock for a 

   # fraction longer 

   #

   db2 eval {

      SELECT * FROM t2

   }

 } {2}

 do_test lock4-999.1 {

   rename db2 {}

 } {}

 finish_test