Upgrade to Transaction::Simple 1.3

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3875 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

2 files changed, 695 insertions, 702 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 3ddf180e0d..1a2cd15458 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Upgrade to Transaction::Simple 1.3 [Jamis Buck]
+
 * Catch FixtureClassNotFound when using instantiated fixtures on a fixture that has no ActiveRecord model [Rick Olson]
 
 * Allow ordering of calculated results and/or grouped fields in calculations [solo@gatelys.com]
diff --git a/activerecord/lib/active_record/vendor/simple.rb b/activerecord/lib/active_record/vendor/simple.rb
index 1bd332c882..7ac3cd08ec 100644
--- a/activerecord/lib/active_record/vendor/simple.rb
+++ b/activerecord/lib/active_record/vendor/simple.rb
@@ -1,702 +1,693 @@
-# :title: Transaction::Simple

-#

-# == Licence

-#

-# Permission is hereby granted, free of charge, to any person obtaining a copy

-# of this software and associated documentation files (the "Software"), to

-# deal in the Software without restriction, including without limitation the

-# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or

-# sell copies of the Software, and to permit persons to whom the Software is

-# furnished to do so, subject to the following conditions:

-#

-# The above copyright notice and this permission notice shall be included in

-# all copies or substantial portions of the Software.

-#

-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

-# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS

-# IN THE SOFTWARE.

-#--

-# Transaction::Simple

-#   Simple object transaction support for Ruby

-#   Version 1.11

-#

-# Copyright (c) 2003 Austin Ziegler

-#

-# $Id: simple.rb,v 1.2 2004/08/20 13:56:37 webster132 Exp $

-#

-# ==========================================================================

-# Revision History ::

-# YYYY.MM.DD  Change ID   Developer

-#             Description

-# --------------------------------------------------------------------------

-# 2003.07.29              Austin Ziegler

-#             Added debugging capabilities and VERSION string.

-# 2003.08.21              Austin Ziegler

-#             Added named transactions.

-#

-# ==========================================================================

-#++

-require 'thread'

-

-  # The "Transaction" namespace can be used for additional transactional

-  # support objects and modules.

-module Transaction

-

-    # A standard exception for transactional errors.

-  class TransactionError < StandardError; end

-    # A standard exception for transactional errors involving the acquisition

-    # of locks for Transaction::Simple::ThreadSafe.

-  class TransactionThreadError < StandardError; end

-

-    # = Transaction::Simple for Ruby

-    # Simple object transaction support for Ruby

-    #

-    # == Introduction

-    #

-    # Transaction::Simple provides a generic way to add active transactional

-    # support to objects. The transaction methods added by this module will

-    # work with most objects, excluding those that cannot be <i>Marshal</i>ed

-    # (bindings, procedure objects, IO instances, or singleton objects).

-    #

-    # The transactions supported by Transaction::Simple are not backed

-    # transactions; that is, they have nothing to do with any sort of data

-    # store. They are "live" transactions occurring in memory and in the

-    # object itself. This is to allow "test" changes to be made to an object

-    # before making the changes permanent.

-    #

-    # Transaction::Simple can handle an "infinite" number of transactional

-    # levels (limited only by memory). If I open two transactions, commit the

-    # first, but abort the second, the object will revert to the original

-    # version.

-    # 

-    # Transaction::Simple supports "named" transactions, so that multiple

-    # levels of transactions can be committed, aborted, or rewound by

-    # referring to the appropriate name of the transaction. Names may be any

-    # object *except* +nil+.

-    #

-    # Copyright::   Copyright © 2003 by Austin Ziegler

-    # Version::     1.1

-    # Licence::     MIT-Style

-    #

-    # Thanks to David Black for help with the initial concept that led to this

-    # library.

-    #

-    # == Usage

-    #   include 'transaction/simple'

-    #

-    #   v = "Hello, you."               # => "Hello, you."

-    #   v.extend(Transaction::Simple)   # => "Hello, you."

-    #

-    #   v.start_transaction             # => ... (a Marshal string)

-    #   v.transaction_open?             # => true

-    #   v.gsub!(/you/, "world")         # => "Hello, world."

-    #

-    #   v.rewind_transaction            # => "Hello, you."

-    #   v.transaction_open?             # => true

-    #

-    #   v.gsub!(/you/, "HAL")           # => "Hello, HAL."

-    #   v.abort_transaction             # => "Hello, you."

-    #   v.transaction_open?             # => false

-    #

-    #   v.start_transaction             # => ... (a Marshal string)

-    #   v.start_transaction             # => ... (a Marshal string)

-    #

-    #   v.transaction_open?             # => true

-    #   v.gsub!(/you/, "HAL")           # => "Hello, HAL."

-    #

-    #   v.commit_transaction            # => "Hello, HAL."

-    #   v.transaction_open?             # => true

-    #   v.abort_transaction             # => "Hello, you."

-    #   v.transaction_open?             # => false

-    #

-    # == Named Transaction Usage

-    #   v = "Hello, you."               # => "Hello, you."

-    #   v.extend(Transaction::Simple)   # => "Hello, you."

-    #   

-    #   v.start_transaction(:first)     # => ... (a Marshal string)

-    #   v.transaction_open?             # => true

-    #   v.transaction_open?(:first)     # => true

-    #   v.transaction_open?(:second)    # => false

-    #   v.gsub!(/you/, "world")         # => "Hello, world."

-    #   

-    #   v.start_transaction(:second)    # => ... (a Marshal string)

-    #   v.gsub!(/world/, "HAL")         # => "Hello, HAL."

-    #   v.rewind_transaction(:first)    # => "Hello, you."

-    #   v.transaction_open?             # => true

-    #   v.transaction_open?(:first)     # => true

-    #   v.transaction_open?(:second)    # => false

-    #   

-    #   v.gsub!(/you/, "world")         # => "Hello, world."

-    #   v.start_transaction(:second)    # => ... (a Marshal string)

-    #   v.gsub!(/world/, "HAL")         # => "Hello, HAL."

-    #   v.transaction_name              # => :second

-    #   v.abort_transaction(:first)     # => "Hello, you."

-    #   v.transaction_open?             # => false

-    #   

-    #   v.start_transaction(:first)     # => ... (a Marshal string)

-    #   v.gsub!(/you/, "world")         # => "Hello, world."

-    #   v.start_transaction(:second)    # => ... (a Marshal string)

-    #   v.gsub!(/world/, "HAL")         # => "Hello, HAL."

-    #   

-    #   v.commit_transaction(:first)    # => "Hello, HAL."

-    #   v.transaction_open?             # => false

-    #

-    # == Contraindications

-    #

-    # While Transaction::Simple is very useful, it has some severe limitations

-    # that must be understood. Transaction::Simple:

-    #

-    # * uses Marshal. Thus, any object which cannot be <i>Marshal</i>ed cannot

-    #   use Transaction::Simple.

-    # * does not manage resources. Resources external to the object and its

-    #   instance variables are not managed at all. However, all instance

-    #   variables and objects "belonging" to those instance variables are

-    #   managed. If there are object reference counts to be handled,

-    #   Transaction::Simple will probably cause problems.

-    # * is not inherently thread-safe. In the ACID ("atomic, consistent,

-    #   isolated, durable") test, Transaction::Simple provides CD, but it is

-    #   up to the user of Transaction::Simple to provide isolation and

-    #   atomicity. Transactions should be considered "critical sections" in

-    #   multi-threaded applications. If thread safety and atomicity is

-    #   absolutely required, use Transaction::Simple::ThreadSafe, which uses a

-    #   Mutex object to synchronize the accesses on the object during the

-    #   transactional operations.

-    # * does not necessarily maintain Object#__id__ values on rewind or abort.

-    #   This may change for future versions that will be Ruby 1.8 or better

-    #   *only*. Certain objects that support #replace will maintain

-    #   Object#__id__.

-    # * Can be a memory hog if you use many levels of transactions on many

-    #   objects.

-    #

-  module Simple

-    VERSION = '1.1.1.0';

-

-      # Sets the Transaction::Simple debug object. It must respond to #<<.

-      # Sets the transaction debug object. Debugging will be performed

-      # automatically if there's a debug object. The generic transaction error

-      # class.

-    def self.debug_io=(io)

-      raise TransactionError, "Transaction Error: the transaction debug object must respond to #<<" unless io.respond_to?(:<<)

-      @tdi = io

-    end

-

-      # Returns the Transaction::Simple debug object. It must respond to #<<.

-    def self.debug_io

-      @tdi

-    end

-

-      # If +name+ is +nil+ (default), then returns +true+ if there is

-      # currently a transaction open.

-      #

-      # If +name+ is specified, then returns +true+ if there is currently a

-      # transaction that responds to +name+ open.

-    def transaction_open?(name = nil)

-      if name.nil?

-        Transaction::Simple.debug_io << "Transaction [#{(@__transaction_checkpoint__.nil?) ? 'closed' : 'open'}]\n" unless Transaction::Simple.debug_io.nil?

-        return (not @__transaction_checkpoint__.nil?)

-      else

-        Transaction::Simple.debug_io << "Transaction(#{name.inspect}) [#{(@__transaction_checkpoint__.nil?) ? 'closed' : 'open'}]\n" unless Transaction::Simple.debug_io.nil?

-        return ((not @__transaction_checkpoint__.nil?) and @__transaction_names__.include?(name))

-      end

-    end

-

-      # Returns the current name of the transaction. Transactions not

-      # explicitly named are named +nil+.

-    def transaction_name

-      raise TransactionError, "Transaction Error: No transaction open." if @__transaction_checkpoint__.nil?

-      Transaction::Simple.debug_io << "#{'|' * @__transaction_level__} Transaction Name: #{@__transaction_names__[-1].inspect}\n" unless Transaction::Simple.debug_io.nil?

-      @__transaction_names__[-1]

-    end

-

-      # Starts a transaction. Stores the current object state. If a

-      # transaction name is specified, the transaction will be named.

-      # Transaction names must be unique. Transaction names of +nil+ will be

-      # treated as unnamed transactions.

-    def start_transaction(name = nil)

-      @__transaction_level__ ||= 0

-      @__transaction_names__ ||= []

-

-      if name.nil?

-        @__transaction_names__ << nil

-        s = ""

-      else

-        raise TransactionError, "Transaction Error: Named transactions must be unique." if @__transaction_names__.include?(name)

-        @__transaction_names__ << name

-        s = "(#{name.inspect})"

-      end

-

-      @__transaction_level__ += 1

-

-      Transaction::Simple.debug_io << "#{'>' * @__transaction_level__} Start Transaction#{s}\n" unless Transaction::Simple.debug_io.nil?

-

-      @__transaction_checkpoint__ = Marshal.dump(self)

-    end

-

-      # Rewinds the transaction. If +name+ is specified, then the intervening

-      # transactions will be aborted and the named transaction will be

-      # rewound. Otherwise, only the current transaction is rewound.

-    def rewind_transaction(name = nil)

-      raise TransactionError, "Transaction Error: Cannot rewind. There is no current transaction." if @__transaction_checkpoint__.nil?

-      if name.nil?

-        __rewind_this_transaction

-        s = ""

-      else

-        raise TransactionError, "Transaction Error: Cannot rewind to transaction #{name.inspect} because it does not exist." unless @__transaction_names__.include?(name)

-        s = "(#{name})"

-

-        while @__transaction_names__[-1] != name

-          @__transaction_checkpoint__ = __rewind_this_transaction

-          Transaction::Simple.debug_io << "#{'|' * @__transaction_level__} Rewind Transaction#{s}\n" unless Transaction::Simple.debug_io.nil?

-          @__transaction_level__ -= 1

-          @__transaction_names__.pop

-        end

-        __rewind_this_transaction

-      end

-      Transaction::Simple.debug_io << "#{'|' * @__transaction_level__} Rewind Transaction#{s}\n" unless Transaction::Simple.debug_io.nil?

-      self

-    end

-

-      # Aborts the transaction. Resets the object state to what it was before

-      # the transaction was started and closes the transaction. If +name+ is

-      # specified, then the intervening transactions and the named transaction

-      # will be aborted. Otherwise, only the current transaction is aborted.

-    def abort_transaction(name = nil)

-      raise TransactionError, "Transaction Error: Cannot abort. There is no current transaction." if @__transaction_checkpoint__.nil?

-      if name.nil?

-        __abort_transaction(name)

-      else

-        raise TransactionError, "Transaction Error: Cannot abort nonexistant transaction #{name.inspect}." unless @__transaction_names__.include?(name)

-

-        __abort_transaction(name) while @__transaction_names__.include?(name)

-      end

-      self

-    end

-

-      # If +name+ is +nil+ (default), the current transaction level is closed

-      # out and the changes are committed.

-      #

-      # If +name+ is specified and +name+ is in the list of named

-      # transactions, then all transactions are closed and committed until the

-      # named transaction is reached.

-    def commit_transaction(name = nil)

-      raise TransactionError, "Transaction Error: Cannot commit. There is no current transaction." if @__transaction_checkpoint__.nil?

-

-      if name.nil?

-        s = ""

-        __commit_transaction

-        Transaction::Simple.debug_io << "#{'<' * @__transaction_level__} Commit Transaction#{s}\n" unless Transaction::Simple.debug_io.nil?

-      else

-        raise TransactionError, "Transaction Error: Cannot commit nonexistant transaction #{name.inspect}." unless @__transaction_names__.include?(name)

-        s = "(#{name})"

-

-        while @__transaction_names__[-1] != name

-          Transaction::Simple.debug_io << "#{'<' * @__transaction_level__} Commit Transaction#{s}\n" unless Transaction::Simple.debug_io.nil?

-          __commit_transaction

-        end

-        Transaction::Simple.debug_io << "#{'<' * @__transaction_level__} Commit Transaction#{s}\n" unless Transaction::Simple.debug_io.nil?

-        __commit_transaction

-      end

-      self

-    end

-

-      # Alternative method for calling the transaction methods. An optional

-      # name can be specified for named transaction support.

-      #

-      # #transaction(:start)::  #start_transaction

-      # #transaction(:rewind):: #rewind_transaction

-      # #transaction(:abort)::  #abort_transaction

-      # #transaction(:commit):: #commit_transaction

-      # #transaction(:name)::   #transaction_name

-      # #transaction::          #transaction_open?

-    def transaction(action = nil, name = nil)

-      case action

-      when :start

-        start_transaction(name)

-      when :rewind

-        rewind_transaction(name)

-      when :abort

-        abort_transaction(name)

-      when :commit

-        commit_transaction(name)

-      when :name

-        transaction_name

-      when nil

-        transaction_open?(name)

-      end

-    end

-

-    def __abort_transaction(name = nil) #:nodoc:

-      @__transaction_checkpoint__ = __rewind_this_transaction

-

-      if name.nil?

-        s = ""

-      else

-        s = "(#{name.inspect})"

-      end

-

-      Transaction::Simple.debug_io << "#{'<' * @__transaction_level__} Abort Transaction#{s}\n" unless Transaction::Simple.debug_io.nil?

-      @__transaction_level__ -= 1

-      @__transaction_names__.pop

-      if @__transaction_level__ < 1

-        @__transaction_level__ = 0

-        @__transaction_names__ = []

-      end

-    end

-

-    TRANSACTION_CHECKPOINT  = "@__transaction_checkpoint__" #:nodoc:

-    SKIP_TRANSACTION_VARS   = [TRANSACTION_CHECKPOINT, "@__transaction_level__"] #:nodoc:

-

-    def __rewind_this_transaction #:nodoc:

-      r = Marshal.restore(@__transaction_checkpoint__)

-

-      begin

-        self.replace(r) if respond_to?(:replace)

-      rescue

-        nil

-      end

-

-      r.instance_variables.each do |i|

-        next if SKIP_TRANSACTION_VARS.include?(i)

-        if respond_to?(:instance_variable_get)

-          instance_variable_set(i, r.instance_variable_get(i))

-        else

-          instance_eval(%q|#{i} = r.instance_eval("#{i}")|)

-        end

-      end

-

-      if respond_to?(:instance_variable_get)

-        return r.instance_variable_get(TRANSACTION_CHECKPOINT)

-      else

-        return r.instance_eval(TRANSACTION_CHECKPOINT)

-      end

-    end

-

-    def __commit_transaction #:nodoc:

-      if respond_to?(:instance_variable_get)

-        @__transaction_checkpoint__ = Marshal.restore(@__transaction_checkpoint__).instance_variable_get(TRANSACTION_CHECKPOINT)

-      else

-        @__transaction_checkpoint__ = Marshal.restore(@__transaction_checkpoint__).instance_eval(TRANSACTION_CHECKPOINT)

-      end

-

-      @__transaction_level__ -= 1

-      @__transaction_names__.pop

-      if @__transaction_level__ < 1

-        @__transaction_level__ = 0

-        @__transaction_names__ = []

-      end

-    end

-

-    private :__abort_transaction, :__rewind_this_transaction, :__commit_transaction

-

-      # = Transaction::Simple::ThreadSafe

-      # Thread-safe simple object transaction support for Ruby.

-      # Transaction::Simple::ThreadSafe is used in the same way as

-      # Transaction::Simple. Transaction::Simple::ThreadSafe uses a Mutex

-      # object to ensure atomicity at the cost of performance in threaded

-      # applications.

-      #

-      # Transaction::Simple::ThreadSafe will not wait to obtain a lock; if the

-      # lock cannot be obtained immediately, a

-      # Transaction::TransactionThreadError will be raised.

-      #

-      # Thanks to Mauricio Fernández for help with getting this part working.

-    module ThreadSafe

-      VERSION = '1.1.1.0';

-

-      include Transaction::Simple

-

-      SKIP_TRANSACTION_VARS = Transaction::Simple::SKIP_TRANSACTION_VARS.dup #:nodoc:

-      SKIP_TRANSACTION_VARS << "@__transaction_mutex__"

-

-      Transaction::Simple.instance_methods(false) do |meth|

-        next if meth == "transaction"

-        arg = "(name = nil)" unless meth == "transaction_name"

-        module_eval <<-EOS

-          def #{meth}#{arg}

-            if (@__transaction_mutex__ ||= Mutex.new).try_lock

-              result = super

-              @__transaction_mutex__.unlock

-              return result

-            else

-              raise TransactionThreadError, "Transaction Error: Cannot obtain lock for ##{meth}"

-            end

-          ensure

-            @__transaction_mutex__.unlock

-          end

-        EOS

-      end

-    end

-  end

-end

-

-if $0 == __FILE__

-  require 'test/unit'

-

-  class Test__Transaction_Simple < Test::Unit::TestCase #:nodoc:

-    VALUE = "Now is the time for all good men to come to the aid of their country."

-

-    def setup

-      @value = VALUE.dup

-      @value.extend(Transaction::Simple)

-    end

-

-    def test_extended

-      assert_respond_to(@value, :start_transaction)

-    end

-

-    def test_started

-      assert_equal(false, @value.transaction_open?)

-      assert_nothing_raised { @value.start_transaction }

-      assert_equal(true, @value.transaction_open?)

-    end

-

-    def test_rewind

-      assert_equal(false, @value.transaction_open?)

-      assert_raises(Transaction::TransactionError) { @value.rewind_transaction }

-      assert_nothing_raised { @value.start_transaction }

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.gsub!(/men/, 'women') }

-      assert_not_equal(VALUE, @value)

-      assert_nothing_raised { @value.rewind_transaction }

-      assert_equal(true, @value.transaction_open?)

-      assert_equal(VALUE, @value)

-    end

-

-    def test_abort

-      assert_equal(false, @value.transaction_open?)

-      assert_raises(Transaction::TransactionError) { @value.abort_transaction }

-      assert_nothing_raised { @value.start_transaction }

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.gsub!(/men/, 'women') }

-      assert_not_equal(VALUE, @value)

-      assert_nothing_raised { @value.abort_transaction }

-      assert_equal(false, @value.transaction_open?)

-      assert_equal(VALUE, @value)

-    end

-

-    def test_commit

-      assert_equal(false, @value.transaction_open?)

-      assert_raises(Transaction::TransactionError) { @value.commit_transaction }

-      assert_nothing_raised { @value.start_transaction }

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.gsub!(/men/, 'women') }

-      assert_not_equal(VALUE, @value)

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.commit_transaction }

-      assert_equal(false, @value.transaction_open?)

-      assert_not_equal(VALUE, @value)

-    end

-

-    def test_multilevel

-      assert_equal(false, @value.transaction_open?)

-      assert_nothing_raised { @value.start_transaction }

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.gsub!(/men/, 'women') }

-      assert_equal(VALUE.gsub(/men/, 'women'), @value)

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.start_transaction }

-      assert_nothing_raised { @value.gsub!(/country/, 'nation-state') }

-      assert_nothing_raised { @value.commit_transaction }

-      assert_equal(VALUE.gsub(/men/, 'women').gsub(/country/, 'nation-state'), @value)

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.abort_transaction }

-      assert_equal(VALUE, @value)

-    end

-

-    def test_multilevel_named

-      assert_equal(false, @value.transaction_open?)

-      assert_raises(Transaction::TransactionError) { @value.transaction_name }

-      assert_nothing_raised { @value.start_transaction(:first) } # 1

-      assert_raises(Transaction::TransactionError) { @value.start_transaction(:first) }

-      assert_equal(true, @value.transaction_open?)

-      assert_equal(true, @value.transaction_open?(:first))

-      assert_equal(:first, @value.transaction_name)

-      assert_nothing_raised { @value.start_transaction } # 2

-      assert_not_equal(:first, @value.transaction_name)

-      assert_equal(nil, @value.transaction_name)

-      assert_raises(Transaction::TransactionError) { @value.abort_transaction(:second) }

-      assert_nothing_raised { @value.abort_transaction(:first) }

-      assert_equal(false, @value.transaction_open?)

-      assert_nothing_raised do

-        @value.start_transaction(:first)

-        @value.gsub!(/men/, 'women')

-        @value.start_transaction(:second)

-        @value.gsub!(/women/, 'people')

-        @value.start_transaction

-        @value.gsub!(/people/, 'sentients')

-      end

-      assert_nothing_raised { @value.abort_transaction(:second) }

-      assert_equal(true, @value.transaction_open?(:first))

-      assert_equal(VALUE.gsub(/men/, 'women'), @value)

-      assert_nothing_raised do

-        @value.start_transaction(:second)

-        @value.gsub!(/women/, 'people')

-        @value.start_transaction

-        @value.gsub!(/people/, 'sentients')

-      end

-      assert_raises(Transaction::TransactionError) { @value.rewind_transaction(:foo) }

-      assert_nothing_raised { @value.rewind_transaction(:second) }

-      assert_equal(VALUE.gsub(/men/, 'women'), @value)

-      assert_nothing_raised do

-        @value.gsub!(/women/, 'people')

-        @value.start_transaction

-        @value.gsub!(/people/, 'sentients')

-      end

-      assert_raises(Transaction::TransactionError) { @value.commit_transaction(:foo) }

-      assert_nothing_raised { @value.commit_transaction(:first) }

-      assert_equal(VALUE.gsub(/men/, 'sentients'), @value)

-      assert_equal(false, @value.transaction_open?)

-    end

-

-    def test_array

-      assert_nothing_raised do

-        @orig = ["first", "second", "third"]

-        @value = ["first", "second", "third"]

-        @value.extend(Transaction::Simple)

-      end

-      assert_equal(@orig, @value)

-      assert_nothing_raised { @value.start_transaction }

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value[1].gsub!(/second/, "fourth") }

-      assert_not_equal(@orig, @value)

-      assert_nothing_raised { @value.abort_transaction }

-      assert_equal(@orig, @value)

-    end

-  end

-

-  class Test__Transaction_Simple_ThreadSafe < Test::Unit::TestCase #:nodoc:

-    VALUE = "Now is the time for all good men to come to the aid of their country."

-

-    def setup

-      @value = VALUE.dup

-      @value.extend(Transaction::Simple::ThreadSafe)

-    end

-

-    def test_extended

-      assert_respond_to(@value, :start_transaction)

-    end

-

-    def test_started

-      assert_equal(false, @value.transaction_open?)

-      assert_nothing_raised { @value.start_transaction }

-      assert_equal(true, @value.transaction_open?)

-    end

-

-    def test_rewind

-      assert_equal(false, @value.transaction_open?)

-      assert_raises(Transaction::TransactionError) { @value.rewind_transaction }

-      assert_nothing_raised { @value.start_transaction }

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.gsub!(/men/, 'women') }

-      assert_not_equal(VALUE, @value)

-      assert_nothing_raised { @value.rewind_transaction }

-      assert_equal(true, @value.transaction_open?)

-      assert_equal(VALUE, @value)

-    end

-

-    def test_abort

-      assert_equal(false, @value.transaction_open?)

-      assert_raises(Transaction::TransactionError) { @value.abort_transaction }

-      assert_nothing_raised { @value.start_transaction }

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.gsub!(/men/, 'women') }

-      assert_not_equal(VALUE, @value)

-      assert_nothing_raised { @value.abort_transaction }

-      assert_equal(false, @value.transaction_open?)

-      assert_equal(VALUE, @value)

-    end

-

-    def test_commit

-      assert_equal(false, @value.transaction_open?)

-      assert_raises(Transaction::TransactionError) { @value.commit_transaction }

-      assert_nothing_raised { @value.start_transaction }

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.gsub!(/men/, 'women') }

-      assert_not_equal(VALUE, @value)

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.commit_transaction }

-      assert_equal(false, @value.transaction_open?)

-      assert_not_equal(VALUE, @value)

-    end

-

-    def test_multilevel

-      assert_equal(false, @value.transaction_open?)

-      assert_nothing_raised { @value.start_transaction }

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.gsub!(/men/, 'women') }

-      assert_equal(VALUE.gsub(/men/, 'women'), @value)

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.start_transaction }

-      assert_nothing_raised { @value.gsub!(/country/, 'nation-state') }

-      assert_nothing_raised { @value.commit_transaction }

-      assert_equal(VALUE.gsub(/men/, 'women').gsub(/country/, 'nation-state'), @value)

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value.abort_transaction }

-      assert_equal(VALUE, @value)

-    end

-

-    def test_multilevel_named

-      assert_equal(false, @value.transaction_open?)

-      assert_raises(Transaction::TransactionError) { @value.transaction_name }

-      assert_nothing_raised { @value.start_transaction(:first) } # 1

-      assert_raises(Transaction::TransactionError) { @value.start_transaction(:first) }

-      assert_equal(true, @value.transaction_open?)

-      assert_equal(true, @value.transaction_open?(:first))

-      assert_equal(:first, @value.transaction_name)

-      assert_nothing_raised { @value.start_transaction } # 2

-      assert_not_equal(:first, @value.transaction_name)

-      assert_equal(nil, @value.transaction_name)

-      assert_raises(Transaction::TransactionError) { @value.abort_transaction(:second) }

-      assert_nothing_raised { @value.abort_transaction(:first) }

-      assert_equal(false, @value.transaction_open?)

-      assert_nothing_raised do

-        @value.start_transaction(:first)

-        @value.gsub!(/men/, 'women')

-        @value.start_transaction(:second)

-        @value.gsub!(/women/, 'people')

-        @value.start_transaction

-        @value.gsub!(/people/, 'sentients')

-      end

-      assert_nothing_raised { @value.abort_transaction(:second) }

-      assert_equal(true, @value.transaction_open?(:first))

-      assert_equal(VALUE.gsub(/men/, 'women'), @value)

-      assert_nothing_raised do

-        @value.start_transaction(:second)

-        @value.gsub!(/women/, 'people')

-        @value.start_transaction

-        @value.gsub!(/people/, 'sentients')

-      end

-      assert_raises(Transaction::TransactionError) { @value.rewind_transaction(:foo) }

-      assert_nothing_raised { @value.rewind_transaction(:second) }

-      assert_equal(VALUE.gsub(/men/, 'women'), @value)

-      assert_nothing_raised do

-        @value.gsub!(/women/, 'people')

-        @value.start_transaction

-        @value.gsub!(/people/, 'sentients')

-      end

-      assert_raises(Transaction::TransactionError) { @value.commit_transaction(:foo) }

-      assert_nothing_raised { @value.commit_transaction(:first) }

-      assert_equal(VALUE.gsub(/men/, 'sentients'), @value)

-      assert_equal(false, @value.transaction_open?)

-    end

-

-    def test_array

-      assert_nothing_raised do

-        @orig = ["first", "second", "third"]

-        @value = ["first", "second", "third"]

-        @value.extend(Transaction::Simple::ThreadSafe)

-      end

-      assert_equal(@orig, @value)

-      assert_nothing_raised { @value.start_transaction }

-      assert_equal(true, @value.transaction_open?)

-      assert_nothing_raised { @value[1].gsub!(/second/, "fourth") }

-      assert_not_equal(@orig, @value)

-      assert_nothing_raised { @value.abort_transaction }

-      assert_equal(@orig, @value)

-    end

-  end

-end

+# :title: Transaction::Simple -- Active Object Transaction Support for Ruby
+# :main: Transaction::Simple
+#
+# == Licence
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and associated documentation files (the "Software"),
+# to deal in the Software without restriction, including without limitation
+# the rights to use, copy, modify, merge, publish, distribute, sublicense,
+# and/or sell copies of the Software, and to permit persons to whom the
+# Software is furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+# DEALINGS IN THE SOFTWARE.
+#--
+# Transaction::Simple
+#   Simple object transaction support for Ruby
+#   Version 1.3.0
+#
+# Copyright (c) 2003 - 2005 Austin Ziegler
+#
+# $Id: simple.rb,v 1.5 2005/05/05 16:16:49 austin Exp $
+#++
+  # The "Transaction" namespace can be used for additional transaction
+  # support objects and modules.
+module Transaction
+    # A standard exception for transaction errors.
+  class TransactionError < StandardError; end
+    # The TransactionAborted exception is used to indicate when a
+    # transaction has been aborted in the block form.
+  class TransactionAborted < Exception; end
+    # The TransactionCommitted exception is used to indicate when a
+    # transaction has been committed in the block form.
+  class TransactionCommitted < Exception; end
+
+  te = "Transaction Error: %s"
+
+  Messages = {
+    :bad_debug_object =>
+      te % "the transaction debug object must respond to #<<.",
+    :unique_names =>
+      te % "named transactions must be unique.",
+    :no_transaction_open =>
+      te % "no transaction open.",
+    :cannot_rewind_no_transaction =>
+      te % "cannot rewind; there is no current transaction.",
+    :cannot_rewind_named_transaction =>
+      te % "cannot rewind to transaction %s because it does not exist.",
+    :cannot_rewind_transaction_before_block =>
+      te % "cannot rewind a transaction started before the execution block.",
+    :cannot_abort_no_transaction =>
+      te % "cannot abort; there is no current transaction.",
+    :cannot_abort_transaction_before_block =>
+      te % "cannot abort a transaction started before the execution block.",
+    :cannot_abort_named_transaction =>
+      te % "cannot abort nonexistant transaction %s.",
+    :cannot_commit_no_transaction =>
+      te % "cannot commit; there is no current transaction.",
+    :cannot_commit_transaction_before_block =>
+      te % "cannot commit a transaction started before the execution block.",
+    :cannot_commit_named_transaction =>
+      te % "cannot commit nonexistant transaction %s.",
+    :cannot_start_empty_block_transaction =>
+      te % "cannot start a block transaction with no objects.",
+    :cannot_obtain_transaction_lock =>
+      te % "cannot obtain transaction lock for #%s.",
+  }
+
+    # = Transaction::Simple for Ruby
+    # Simple object transaction support for Ruby
+    #
+    # == Introduction
+    # Transaction::Simple provides a generic way to add active transaction
+    # support to objects. The transaction methods added by this module will
+    # work with most objects, excluding those that cannot be
+    # <i>Marshal</i>ed (bindings, procedure objects, IO instances, or
+    # singleton objects).
+    #
+    # The transactions supported by Transaction::Simple are not backed
+    # transactions; they are not associated with any sort of data store.
+    # They are "live" transactions occurring in memory and in the object
+    # itself. This is to allow "test" changes to be made to an object
+    # before making the changes permanent.
+    #
+    # Transaction::Simple can handle an "infinite" number of transaction
+    # levels (limited only by memory). If I open two transactions, commit
+    # the second, but abort the first, the object will revert to the
+    # original version.
+    # 
+    # Transaction::Simple supports "named" transactions, so that multiple
+    # levels of transactions can be committed, aborted, or rewound by
+    # referring to the appropriate name of the transaction. Names may be any
+    # object *except* +nil+. As with Hash keys, String names will be
+    # duplicated and frozen before using.
+    #
+    # Copyright::   Copyright © 2003 - 2005 by Austin Ziegler
+    # Version::     1.3.0
+    # Licence::     MIT-Style
+    #
+    # Thanks to David Black for help with the initial concept that led to
+    # this library.
+    #
+    # == Usage
+    #   include 'transaction/simple'
+    #
+    #   v = "Hello, you."               # -> "Hello, you."
+    #   v.extend(Transaction::Simple)   # -> "Hello, you."
+    #
+    #   v.start_transaction             # -> ... (a Marshal string)
+    #   v.transaction_open?             # -> true
+    #   v.gsub!(/you/, "world")         # -> "Hello, world."
+    #
+    #   v.rewind_transaction            # -> "Hello, you."
+    #   v.transaction_open?             # -> true
+    #
+    #   v.gsub!(/you/, "HAL")           # -> "Hello, HAL."
+    #   v.abort_transaction             # -> "Hello, you."
+    #   v.transaction_open?             # -> false
+    #
+    #   v.start_transaction             # -> ... (a Marshal string)
+    #   v.start_transaction             # -> ... (a Marshal string)
+    #
+    #   v.transaction_open?             # -> true
+    #   v.gsub!(/you/, "HAL")           # -> "Hello, HAL."
+    #
+    #   v.commit_transaction            # -> "Hello, HAL."
+    #   v.transaction_open?             # -> true
+    #   v.abort_transaction             # -> "Hello, you."
+    #   v.transaction_open?             # -> false
+    #
+    # == Named Transaction Usage
+    #   v = "Hello, you."               # -> "Hello, you."
+    #   v.extend(Transaction::Simple)   # -> "Hello, you."
+    #   
+    #   v.start_transaction(:first)     # -> ... (a Marshal string)
+    #   v.transaction_open?             # -> true
+    #   v.transaction_open?(:first)     # -> true
+    #   v.transaction_open?(:second)    # -> false
+    #   v.gsub!(/you/, "world")         # -> "Hello, world."
+    #   
+    #   v.start_transaction(:second)    # -> ... (a Marshal string)
+    #   v.gsub!(/world/, "HAL")         # -> "Hello, HAL."
+    #   v.rewind_transaction(:first)    # -> "Hello, you."
+    #   v.transaction_open?             # -> true
+    #   v.transaction_open?(:first)     # -> true
+    #   v.transaction_open?(:second)    # -> false
+    #   
+    #   v.gsub!(/you/, "world")         # -> "Hello, world."
+    #   v.start_transaction(:second)    # -> ... (a Marshal string)
+    #   v.gsub!(/world/, "HAL")         # -> "Hello, HAL."
+    #   v.transaction_name              # -> :second
+    #   v.abort_transaction(:first)     # -> "Hello, you."
+    #   v.transaction_open?             # -> false
+    #   
+    #   v.start_transaction(:first)     # -> ... (a Marshal string)
+    #   v.gsub!(/you/, "world")         # -> "Hello, world."
+    #   v.start_transaction(:second)    # -> ... (a Marshal string)
+    #   v.gsub!(/world/, "HAL")         # -> "Hello, HAL."
+    #   
+    #   v.commit_transaction(:first)    # -> "Hello, HAL."
+    #   v.transaction_open?             # -> false
+    #
+    # == Block Usage
+    #   v = "Hello, you."               # -> "Hello, you."
+    #   Transaction::Simple.start(v) do |tv|
+    #       # v has been extended with Transaction::Simple and an unnamed
+    #       # transaction has been started.
+    #     tv.transaction_open?          # -> true
+    #     tv.gsub!(/you/, "world")      # -> "Hello, world."
+    #
+    #     tv.rewind_transaction         # -> "Hello, you."
+    #     tv.transaction_open?          # -> true
+    #
+    #     tv.gsub!(/you/, "HAL")        # -> "Hello, HAL."
+    #       # The following breaks out of the transaction block after
+    #       # aborting the transaction.
+    #     tv.abort_transaction          # -> "Hello, you."
+    #   end
+    #     # v still has Transaction::Simple applied from here on out.
+    #   v.transaction_open?             # -> false
+    #
+    #   Transaction::Simple.start(v) do |tv|
+    #     tv.start_transaction          # -> ... (a Marshal string)
+    #
+    #     tv.transaction_open?          # -> true
+    #     tv.gsub!(/you/, "HAL")        # -> "Hello, HAL."
+    #
+    #       # If #commit_transaction were called without having started a
+    #       # second transaction, then it would break out of the transaction
+    #       # block after committing the transaction.
+    #     tv.commit_transaction         # -> "Hello, HAL."
+    #     tv.transaction_open?          # -> true
+    #     tv.abort_transaction          # -> "Hello, you."
+    #   end
+    #   v.transaction_open?             # -> false
+    #
+    # == Named Transaction Usage
+    #   v = "Hello, you."               # -> "Hello, you."
+    #   v.extend(Transaction::Simple)   # -> "Hello, you."
+    #   
+    #   v.start_transaction(:first)     # -> ... (a Marshal string)
+    #   v.transaction_open?             # -> true
+    #   v.transaction_open?(:first)     # -> true
+    #   v.transaction_open?(:second)    # -> false
+    #   v.gsub!(/you/, "world")         # -> "Hello, world."
+    #   
+    #   v.start_transaction(:second)    # -> ... (a Marshal string)
+    #   v.gsub!(/world/, "HAL")         # -> "Hello, HAL."
+    #   v.rewind_transaction(:first)    # -> "Hello, you."
+    #   v.transaction_open?             # -> true
+    #   v.transaction_open?(:first)     # -> true
+    #   v.transaction_open?(:second)    # -> false
+    #   
+    #   v.gsub!(/you/, "world")         # -> "Hello, world."
+    #   v.start_transaction(:second)    # -> ... (a Marshal string)
+    #   v.gsub!(/world/, "HAL")         # -> "Hello, HAL."
+    #   v.transaction_name              # -> :second
+    #   v.abort_transaction(:first)     # -> "Hello, you."
+    #   v.transaction_open?             # -> false
+    #   
+    #   v.start_transaction(:first)     # -> ... (a Marshal string)
+    #   v.gsub!(/you/, "world")         # -> "Hello, world."
+    #   v.start_transaction(:second)    # -> ... (a Marshal string)
+    #   v.gsub!(/world/, "HAL")         # -> "Hello, HAL."
+    #   
+    #   v.commit_transaction(:first)    # -> "Hello, HAL."
+    #   v.transaction_open?             # -> false
+    #
+    # == Thread Safety
+    # Threadsafe version of Transaction::Simple and
+    # Transaction::Simple::Group exist; these are loaded from
+    # 'transaction/simple/threadsafe' and
+    # 'transaction/simple/threadsafe/group', respectively, and are
+    # represented in Ruby code as Transaction::Simple::ThreadSafe and
+    # Transaction::Simple::ThreadSafe::Group, respectively.
+    #
+    # == Contraindications
+    # While Transaction::Simple is very useful, it has some severe
+    # limitations that must be understood. Transaction::Simple:
+    #
+    # * uses Marshal. Thus, any object which cannot be <i>Marshal</i>ed
+    #   cannot use Transaction::Simple. In my experience, this affects
+    #   singleton objects more often than any other object. It may be that
+    #   Ruby 2.0 will solve this problem.
+    # * does not manage resources. Resources external to the object and its
+    #   instance variables are not managed at all. However, all instance
+    #   variables and objects "belonging" to those instance variables are
+    #   managed. If there are object reference counts to be handled,
+    #   Transaction::Simple will probably cause problems.
+    # * is not inherently thread-safe. In the ACID ("atomic, consistent,
+    #   isolated, durable") test, Transaction::Simple provides CD, but it is
+    #   up to the user of Transaction::Simple to provide isolation and
+    #   atomicity. Transactions should be considered "critical sections" in
+    #   multi-threaded applications. If thread safety and atomicity is
+    #   absolutely required, use Transaction::Simple::ThreadSafe, which uses
+    #   a Mutex object to synchronize the accesses on the object during the
+    #   transaction operations.
+    # * does not necessarily maintain Object#__id__ values on rewind or
+    #   abort. This may change for future versions that will be Ruby 1.8 or
+    #   better *only*. Certain objects that support #replace will maintain
+    #   Object#__id__.
+    # * Can be a memory hog if you use many levels of transactions on many
+    #   objects.
+    #
+  module Simple
+    TRANSACTION_SIMPLE_VERSION = '1.3.0'
+
+      # Sets the Transaction::Simple debug object. It must respond to #<<.
+      # Sets the transaction debug object. Debugging will be performed
+      # automatically if there's a debug object. The generic transaction
+      # error class.
+    def self.debug_io=(io)
+      if io.nil?
+        @tdi        = nil
+        @debugging  = false
+      else
+        unless io.respond_to?(:<<)
+          raise TransactionError, Messages[:bad_debug_object]
+        end
+        @tdi = io
+        @debugging = true
+      end
+    end
+
+      # Returns +true+ if we are debugging.
+    def self.debugging?
+      @debugging
+    end
+
+      # Returns the Transaction::Simple debug object. It must respond to
+      # #<<.
+    def self.debug_io
+      @tdi ||= ""
+      @tdi
+    end
+
+      # If +name+ is +nil+ (default), then returns +true+ if there is
+      # currently a transaction open.
+      #
+      # If +name+ is specified, then returns +true+ if there is currently a
+      # transaction that responds to +name+ open.
+    def transaction_open?(name = nil)
+      if name.nil?
+        if Transaction::Simple.debugging?
+          Transaction::Simple.debug_io << "Transaction " <<
+            "[#{(@__transaction_checkpoint__.nil?) ? 'closed' : 'open'}]\n"
+        end
+        return (not @__transaction_checkpoint__.nil?)
+      else
+        if Transaction::Simple.debugging?
+          Transaction::Simple.debug_io << "Transaction(#{name.inspect}) " <<
+            "[#{(@__transaction_checkpoint__.nil?) ? 'closed' : 'open'}]\n"
+        end
+        return ((not @__transaction_checkpoint__.nil?) and @__transaction_names__.include?(name))
+      end
+    end
+
+      # Returns the current name of the transaction. Transactions not
+      # explicitly named are named +nil+.
+    def transaction_name
+      if @__transaction_checkpoint__.nil?
+        raise TransactionError, Messages[:no_transaction_open]
+      end
+      if Transaction::Simple.debugging?
+        Transaction::Simple.debug_io << "#{'|' * @__transaction_level__} " <<
+          "Transaction Name: #{@__transaction_names__[-1].inspect}\n"
+      end
+      if @__transaction_names__[-1].kind_of?(String)
+        @__transaction_names__[-1].dup
+      else
+        @__transaction_names__[-1]
+      end
+    end
+
+      # Starts a transaction. Stores the current object state. If a
+      # transaction name is specified, the transaction will be named.
+      # Transaction names must be unique. Transaction names of +nil+ will be
+      # treated as unnamed transactions.
+    def start_transaction(name = nil)
+      @__transaction_level__ ||= 0
+      @__transaction_names__ ||= []
+
+      if name.nil?
+        @__transaction_names__ << nil
+        ss = "" if Transaction::Simple.debugging?
+      else
+        if @__transaction_names__.include?(name)
+          raise TransactionError, Messages[:unique_names]
+        end
+        name = name.dup.freeze if name.kind_of?(String)
+        @__transaction_names__ << name
+        ss = "(#{name.inspect})" if Transaction::Simple.debugging?
+      end
+
+      @__transaction_level__ += 1
+
+      if Transaction::Simple.debugging?
+        Transaction::Simple.debug_io << "#{'>' * @__transaction_level__} " <<
+          "Start Transaction#{ss}\n"
+      end
+
+      @__transaction_checkpoint__ = Marshal.dump(self)
+    end
+
+      # Rewinds the transaction. If +name+ is specified, then the
+      # intervening transactions will be aborted and the named transaction
+      # will be rewound. Otherwise, only the current transaction is rewound.
+    def rewind_transaction(name = nil)
+      if @__transaction_checkpoint__.nil?
+        raise TransactionError, Messages[:cannot_rewind_no_transaction]
+      end
+
+        # Check to see if we are trying to rewind a transaction that is
+        # outside of the current transaction block.
+      if @__transaction_block__ and name
+        nix = @__transaction_names__.index(name) + 1
+        if nix < @__transaction_block__
+          raise TransactionError, Messages[:cannot_rewind_transaction_before_block]
+        end
+      end
+
+      if name.nil?
+        __rewind_this_transaction
+        ss = "" if Transaction::Simple.debugging?
+      else
+        unless @__transaction_names__.include?(name)
+          raise TransactionError, Messages[:cannot_rewind_named_transaction] % name.inspect
+        end
+        ss = "(#{name})" if Transaction::Simple.debugging?
+
+        while @__transaction_names__[-1] != name
+          @__transaction_checkpoint__ = __rewind_this_transaction
+          if Transaction::Simple.debugging?
+            Transaction::Simple.debug_io << "#{'|' * @__transaction_level__} " <<
+              "Rewind Transaction#{ss}\n"
+          end
+          @__transaction_level__ -= 1
+          @__transaction_names__.pop
+        end
+        __rewind_this_transaction
+      end
+      if Transaction::Simple.debugging?
+        Transaction::Simple.debug_io << "#{'|' * @__transaction_level__} " <<
+          "Rewind Transaction#{ss}\n"
+      end
+      self
+    end
+
+      # Aborts the transaction. Resets the object state to what it was
+      # before the transaction was started and closes the transaction. If
+      # +name+ is specified, then the intervening transactions and the named
+      # transaction will be aborted. Otherwise, only the current transaction
+      # is aborted.
+      #
+      # If the current or named transaction has been started by a block
+      # (Transaction::Simple.start), then the execution of the block will be
+      # halted with +break+ +self+.
+    def abort_transaction(name = nil)
+      if @__transaction_checkpoint__.nil?
+        raise TransactionError, Messages[:cannot_abort_no_transaction]
+      end
+
+        # Check to see if we are trying to abort a transaction that is
+        # outside of the current transaction block. Otherwise, raise
+        # TransactionAborted if they are the same.
+      if @__transaction_block__ and name
+        nix = @__transaction_names__.index(name) + 1
+        if nix < @__transaction_block__
+          raise TransactionError, Messages[:cannot_abort_transaction_before_block]
+        end
+
+        raise TransactionAborted if @__transaction_block__ == nix
+      end
+
+      raise TransactionAborted if @__transaction_block__ == @__transaction_level__
+
+      if name.nil?
+        __abort_transaction(name)
+      else
+        unless @__transaction_names__.include?(name)
+          raise TransactionError, Messages[:cannot_abort_named_transaction] % name.inspect
+        end
+        __abort_transaction(name) while @__transaction_names__.include?(name)
+      end
+      self
+    end
+
+      # If +name+ is +nil+ (default), the current transaction level is
+      # closed out and the changes are committed.
+      #
+      # If +name+ is specified and +name+ is in the list of named
+      # transactions, then all transactions are closed and committed until
+      # the named transaction is reached.
+    def commit_transaction(name = nil)
+      if @__transaction_checkpoint__.nil?
+        raise TransactionError, Messages[:cannot_commit_no_transaction]
+      end
+      @__transaction_block__ ||= nil
+
+        # Check to see if we are trying to commit a transaction that is
+        # outside of the current transaction block. Otherwise, raise
+        # TransactionCommitted if they are the same.
+      if @__transaction_block__ and name
+        nix = @__transaction_names__.index(name) + 1
+        if nix < @__transaction_block__
+          raise TransactionError, Messages[:cannot_commit_transaction_before_block]
+        end
+
+        raise TransactionCommitted if @__transaction_block__ == nix
+      end
+
+      raise TransactionCommitted if @__transaction_block__ == @__transaction_level__
+
+      if name.nil?
+        ss = "" if Transaction::Simple.debugging?
+        __commit_transaction
+        if Transaction::Simple.debugging?
+          Transaction::Simple.debug_io << "#{'<' * @__transaction_level__} " <<
+            "Commit Transaction#{ss}\n"
+        end
+      else
+        unless @__transaction_names__.include?(name)
+          raise TransactionError, Messages[:cannot_commit_named_transaction] % name.inspect
+        end
+        ss = "(#{name})" if Transaction::Simple.debugging?
+
+        while @__transaction_names__[-1] != name
+          if Transaction::Simple.debugging?
+            Transaction::Simple.debug_io << "#{'<' * @__transaction_level__} " <<
+              "Commit Transaction#{ss}\n"
+          end
+          __commit_transaction
+        end
+        if Transaction::Simple.debugging?
+          Transaction::Simple.debug_io << "#{'<' * @__transaction_level__} " <<
+            "Commit Transaction#{ss}\n"
+        end
+        __commit_transaction
+      end
+
+      self
+    end
+
+      # Alternative method for calling the transaction methods. An optional
+      # name can be specified for named transaction support.
+      #
+      # #transaction(:start)::  #start_transaction
+      # #transaction(:rewind):: #rewind_transaction
+      # #transaction(:abort)::  #abort_transaction
+      # #transaction(:commit):: #commit_transaction
+      # #transaction(:name)::   #transaction_name
+      # #transaction::          #transaction_open?
+    def transaction(action = nil, name = nil)
+      case action
+      when :start
+        start_transaction(name)
+      when :rewind
+        rewind_transaction(name)
+      when :abort
+        abort_transaction(name)
+      when :commit
+        commit_transaction(name)
+      when :name
+        transaction_name
+      when nil
+        transaction_open?(name)
+      end
+    end
+
+      # Allows specific variables to be excluded from transaction support.
+      # Must be done after extending the object but before starting the
+      # first transaction on the object.
+      #
+      #   vv.transaction_exclusions << "@io"
+    def transaction_exclusions
+      @transaction_exclusions ||= []
+    end
+
+    class << self
+      def __common_start(name, vars, &block)
+        if vars.empty?
+          raise TransactionError, Messages[:cannot_start_empty_block_transaction]
+        end
+
+        if block
+          begin
+            vlevel = {}
+
+            vars.each do |vv|
+              vv.extend(Transaction::Simple)
+              vv.start_transaction(name)
+              vlevel[vv.__id__] = vv.instance_variable_get(:@__transaction_level__)
+              vv.instance_variable_set(:@__transaction_block__, vlevel[vv.__id__])
+            end
+
+            yield(*vars)
+          rescue TransactionAborted
+            vars.each do |vv|
+              if name.nil? and vv.transaction_open?
+                loop do
+                  tlevel = vv.instance_variable_get(:@__transaction_level__) || -1
+                  vv.instance_variable_set(:@__transaction_block__, -1)
+                  break if tlevel < vlevel[vv.__id__]
+                  vv.abort_transaction if vv.transaction_open?
+                end
+              elsif vv.transaction_open?(name)
+                vv.instance_variable_set(:@__transaction_block__, -1)
+                vv.abort_transaction(name)
+              end
+            end
+          rescue TransactionCommitted
+            nil
+          ensure
+            vars.each do |vv|
+              if name.nil? and vv.transaction_open?
+                loop do
+                  tlevel = vv.instance_variable_get(:@__transaction_level__) || -1
+                  break if tlevel < vlevel[vv.__id__]
+                  vv.instance_variable_set(:@__transaction_block__, -1)
+                  vv.commit_transaction if vv.transaction_open?
+                end
+              elsif vv.transaction_open?(name)
+                vv.instance_variable_set(:@__transaction_block__, -1)
+                vv.commit_transaction(name)
+              end
+            end
+          end
+        else
+          vars.each do |vv|
+            vv.extend(Transaction::Simple)
+            vv.start_transaction(name)
+          end
+        end
+      end
+      private :__common_start
+
+      def start_named(name, *vars, &block)
+        __common_start(name, vars, &block)
+      end
+
+      def start(*vars, &block)
+        __common_start(nil, vars, &block)
+      end
+    end
+
+    def __abort_transaction(name = nil) #:nodoc:
+      @__transaction_checkpoint__ = __rewind_this_transaction
+
+      if name.nil?
+        ss = "" if Transaction::Simple.debugging?
+      else
+        ss = "(#{name.inspect})" if Transaction::Simple.debugging?
+      end
+
+      if Transaction::Simple.debugging?
+        Transaction::Simple.debug_io << "#{'<' * @__transaction_level__} " <<
+          "Abort Transaction#{ss}\n"
+      end
+      @__transaction_level__ -= 1
+      @__transaction_names__.pop
+      if @__transaction_level__ < 1
+        @__transaction_level__ = 0
+        @__transaction_names__ = []
+      end
+    end
+
+    TRANSACTION_CHECKPOINT  = "@__transaction_checkpoint__" #:nodoc:
+    SKIP_TRANSACTION_VARS   = [TRANSACTION_CHECKPOINT, "@__transaction_level__"] #:nodoc:
+
+    def __rewind_this_transaction #:nodoc:
+      rr = Marshal.restore(@__transaction_checkpoint__)
+
+      begin
+        self.replace(rr) if respond_to?(:replace)
+      rescue
+        nil
+      end
+
+      rr.instance_variables.each do |vv|
+        next if SKIP_TRANSACTION_VARS.include?(vv)
+        next if self.transaction_exclusions.include?(vv)
+        if respond_to?(:instance_variable_get)
+          instance_variable_set(vv, rr.instance_variable_get(vv))
+        else
+          instance_eval(%q|#{vv} = rr.instance_eval("#{vv}")|)
+        end
+      end
+
+      new_ivar = instance_variables - rr.instance_variables - SKIP_TRANSACTION_VARS
+      new_ivar.each do |vv|
+        if respond_to?(:instance_variable_set)
+          instance_variable_set(vv, nil)
+        else
+          instance_eval(%q|#{vv} = nil|)
+        end
+      end
+
+      if respond_to?(:instance_variable_get)
+        rr.instance_variable_get(TRANSACTION_CHECKPOINT)
+      else
+        rr.instance_eval(TRANSACTION_CHECKPOINT)
+      end
+    end
+
+    def __commit_transaction #:nodoc:
+      if respond_to?(:instance_variable_get)
+        @__transaction_checkpoint__ = Marshal.restore(@__transaction_checkpoint__).instance_variable_get(TRANSACTION_CHECKPOINT)
+      else
+        @__transaction_checkpoint__ = Marshal.restore(@__transaction_checkpoint__).instance_eval(TRANSACTION_CHECKPOINT)
+      end
+
+      @__transaction_level__ -= 1
+      @__transaction_names__.pop
+
+      if @__transaction_level__ < 1
+        @__transaction_level__ = 0
+        @__transaction_names__ = []
+      end
+    end
+
+    private :__abort_transaction
+    private :__rewind_this_transaction
+    private :__commit_transaction
+  end
+end