Merge commit 'mainstream/master'

Conflicts:

	actionmailer/lib/action_mailer/base.rb
	actionpack/lib/action_controller/base.rb
	actionpack/lib/action_controller/mime_type.rb
	railties/doc/guides/html/activerecord_validations_callbacks.html
	railties/doc/guides/html/caching_with_rails.html
	railties/doc/guides/html/command_line.html
	railties/doc/guides/html/configuring.html
	railties/doc/guides/html/creating_plugins.html
	railties/doc/guides/html/finders.html
	railties/doc/guides/html/routing_outside_in.html
	railties/doc/guides/source/activerecord_validations_callbacks.txt
	railties/doc/guides/source/caching_with_rails.txt
	railties/doc/guides/source/command_line.txt
	railties/doc/guides/source/creating_plugins/acts_as_yaffle.txt
	railties/doc/guides/source/creating_plugins/controllers.txt
	railties/doc/guides/source/creating_plugins/core_ext.txt
	railties/doc/guides/source/creating_plugins/helpers.txt
	railties/doc/guides/source/creating_plugins/index.txt
	railties/doc/guides/source/creating_plugins/migration_generator.txt
	railties/doc/guides/source/creating_plugins/models.txt
	railties/doc/guides/source/creating_plugins/odds_and_ends.txt
	railties/doc/guides/source/creating_plugins/routes.txt
	railties/doc/guides/source/finders.txt
	railties/doc/guides/source/routing_outside_in.txt
	railties/doc/guides/source/testing_rails_applications.txt

1 files changed, 42 insertions, 0 deletions

diff --git a/actionpack/lib/action_controller/middleware_stack.rb b/actionpack/lib/action_controller/middleware_stack.rb
new file mode 100644
index 0000000000..1864bed23a
--- /dev/null
+++ b/actionpack/lib/action_controller/middleware_stack.rb
@@ -0,0 +1,42 @@
+module ActionController
+  class MiddlewareStack < Array
+    class Middleware
+      attr_reader :klass, :args, :block
+
+      def initialize(klass, *args, &block)
+        @klass = klass.is_a?(Class) ? klass : klass.to_s.constantize
+        @args = args
+        @block = block
+      end
+
+      def ==(middleware)
+        case middleware
+        when Middleware
+          klass == middleware.klass
+        when Class
+          klass == middleware
+        else
+          klass == middleware.to_s.constantize
+        end
+      end
+
+      def inspect
+        str = @klass.to_s
+        @args.each { |arg| str += ", #{arg.inspect}" }
+        str
+      end
+
+      def build(app)
+        klass.new(app, *args, &block)
+      end
+    end
+
+    def use(*args, &block)
+      push(Middleware.new(*args, &block))
+    end
+
+    def build(app)
+      reverse.inject(app) { |a, e| e.build(a) }
+    end
+  end
+end