adding a direct dispatch method to controller classes

This saves a lambda and request allocation on each request.

actionpack/lib/action_controller/metal.rb

@@ -259,5 +259,15 @@ def self.action(name)
         lambda { |env| new.dispatch(name, ActionDispatch::Request.new(env)) }
       end
     end
+
+    # Direct dispatch to the controller.  Instantiates the controller, then
+    # executes the action named +name+.
+    def self.dispatch(name, req)
+      if middleware_stack.any?
+        middleware_stack.build(name) { |env| new.dispatch(name, req) }.call req.env
+      else
+        new.dispatch(name, req)
+      end
+    end
   end
 end

actionpack/lib/action_dispatch/routing/route_set.rb

@@ -44,7 +44,7 @@ def controller(req)
         end
 
         def dispatch(controller, action, req)
-          controller.action(action).call(req.env)
+          controller.dispatch(action, req)
         end
       end
 

actionpack/test/abstract_unit.rb

@@ -124,16 +124,10 @@ class DeadEndRoutes < ActionDispatch::Routing::RouteSet
     class NullController
       def initialize(controller_name)
         @controller = controller_name
-        @action = nil
       end
 
-      def action(action_name)
-        @action = action_name
-        self
-      end
-
-      def call(env)
-        [200, {'Content-Type' => 'text/html'}, ["#{@controller}##{@action}"]]
+      def dispatch(action, req)
+        [200, {'Content-Type' => 'text/html'}, ["#{@controller}##{action}"]]
       end
     end