prefer composition over inheritance with AD::MS

3 files changed, 42 insertions, 9 deletions

diff --git a/actionpack/CHANGELOG b/actionpack/CHANGELOG
index ee9d30e1fb..fc3410ba6e 100644
--- a/actionpack/CHANGELOG
+++ b/actionpack/CHANGELOG
@@ -1,5 +1,9 @@
 *Rails 3.1.0 (unreleased)*
 
+* ActionDispatch::MiddlewareStack now uses composition over inheritance. It is
+no longer an array which means there may be methods missing that were not
+tested.
+
 * Add an :authenticity_token option to form_tag for custom handling or to omit the token (pass :authenticity_token => false).  [Jakub Kuźma, Igor Wiedler]
 
 * HTML5 button_tag helper. [Rizwan Reza]
diff --git a/actionpack/lib/action_controller/metal.rb b/actionpack/lib/action_controller/metal.rb
index b2c8053584..e5db31061b 100644
--- a/actionpack/lib/action_controller/metal.rb
+++ b/actionpack/lib/action_controller/metal.rb
@@ -36,7 +36,7 @@ module ActionController
       action = action.to_s
       raise "MiddlewareStack#build requires an app" unless app
 
-      reverse.inject(app) do |a, middleware|
+      middlewares.reverse.inject(app) do |a, middleware|
         middleware.valid?(action) ?
           middleware.build(a) : a
       end
diff --git a/actionpack/lib/action_dispatch/middleware/stack.rb b/actionpack/lib/action_dispatch/middleware/stack.rb
index e3cd779756..852f697d91 100644
--- a/actionpack/lib/action_dispatch/middleware/stack.rb
+++ b/actionpack/lib/action_dispatch/middleware/stack.rb
@@ -2,7 +2,7 @@ require "active_support/inflector/methods"
 require "active_support/dependencies"
 
 module ActionDispatch
-  class MiddlewareStack < Array
+  class MiddlewareStack
     class Middleware
       attr_reader :args, :block
 
@@ -41,18 +41,43 @@ module ActionDispatch
       end
     end
 
-    # Use this instead of super to work around a warning.
-    alias :array_initialize :initialize
+    include Enumerable
+
+    attr_accessor :middlewares
 
     def initialize(*args)
-      array_initialize(*args)
+      @middlewares = []
       yield(self) if block_given?
     end
 
+    def each
+      @middlewares.each { |x| yield x }
+    end
+
+    def size
+      middlewares.size
+    end
+
+    def last
+      middlewares.last
+    end
+
+    def [](i)
+      middlewares[i]
+    end
+
+    def include?(item)
+      middlewares.include? item
+    end
+
+    def initialize_copy(other)
+      self.middlewares = other.middlewares.dup
+    end
+
     def insert(index, *args, &block)
       index = assert_index(index, :before)
       middleware = self.class::Middleware.new(*args, &block)
-      super(index, middleware)
+      middlewares.insert(index, middleware)
     end
 
     alias_method :insert_before, :insert
@@ -67,21 +92,25 @@ module ActionDispatch
       delete(target)
     end
 
+    def delete(target)
+      middlewares.delete target
+    end
+
     def use(*args, &block)
       middleware = self.class::Middleware.new(*args, &block)
-      push(middleware)
+      middlewares.push(middleware)
     end
 
     def build(app = nil, &block)
       app ||= block
       raise "MiddlewareStack#build requires an app" unless app
-      reverse.inject(app) { |a, e| e.build(a) }
+      middlewares.reverse.inject(app) { |a, e| e.build(a) }
     end
 
   protected
 
     def assert_index(index, where)
-      i = index.is_a?(Integer) ? index : self.index(index)
+      i = index.is_a?(Integer) ? index : middlewares.index(index)
       raise "No such middleware to insert #{where}: #{index.inspect}" unless i
       i
     end