Index: mq.rb
===================================================================
--- mq.rb	(revision 13616)
+++ mq.rb	(working copy)
@@ -221,6 +221,10 @@
           MQ.error "Basic.GetEmpty for invalid consumer"
         end

+      when Protocol::Tx::CommitOk
+        tx_callback = (@tx_callback ||= []).shift
+        tx_callback.call if tx_callback
+
       when Protocol::Channel::Close
         raise Error, "#{method.reply_text} in #{Protocol.classes[method.class_id].methods[method.method_id]} on #{@channel}"

@@ -736,6 +740,18 @@
     send Protocol::Basic::Qos.new(:prefetch_size => 0, :prefetch_count => size, :global => false)
   end

+  def transaction(block, commit_callback)
+    send Protocol::Tx::Select.new
+    begin
+      block.call
+      (@tx_callback ||= []) << commit_callback
+      send Protocol::Tx::Commit.new
+    rescue Object
+      send Protocol::Tx::Rollback.new
+      raise
+    end
+  end
+
   # Returns a hash of all the exchange proxy objects.
   #
   # Not typically called by client code.