Changed ActiveSupport::Memoizable API to extend since it mainly adds …

…the memoize class method

actionpack/lib/action_view/renderable.rb

@@ -3,12 +3,12 @@ module Renderable
     # NOTE: The template that this mixin is beening include into is frozen
     # So you can not set or modify any instance variables
 
+    extend ActiveSupport::Memoizable
+
     def self.included(base)
       @@mutex = Mutex.new
     end
 
-    include ActiveSupport::Memoizable
-
     def filename
       'compiled-template'
     end

actionpack/lib/action_view/renderable_partial.rb

@@ -3,7 +3,7 @@ module RenderablePartial
     # NOTE: The template that this mixin is beening include into is frozen
     # So you can not set or modify any instance variables
 
-    include ActiveSupport::Memoizable
+    extend ActiveSupport::Memoizable
 
     def variable_name
       name.sub(/\A_/, '').to_sym

actionpack/lib/action_view/template.rb

@@ -1,7 +1,7 @@
 module ActionView #:nodoc:
   class Template
     extend TemplateHandlers
-    include ActiveSupport::Memoizable
+    extend ActiveSupport::Memoizable
     include Renderable
 
     attr_accessor :filename, :load_path, :base_path, :name, :format, :extension

activesupport/lib/active_support/memoizable.rb

@@ -1,37 +1,38 @@
 module ActiveSupport
-  module Memoizable
-    def self.included(base) #:nodoc:
-      base.extend(ClassMethods)
-    end
-
-    module ClassMethods
-      def memoize(*symbols)
-        symbols.each do |symbol|
-          original_method = "unmemoized_#{symbol}"
-          memoized_ivar = "@#{symbol}"
-          raise "Already memoized #{symbol}" if instance_methods.map(&:to_s).include?(original_method)
-
-          alias_method original_method, symbol
-          class_eval <<-EOS, __FILE__, __LINE__
-            def #{symbol}(reload = false)
-              if !reload && defined? #{memoized_ivar}
-                #{memoized_ivar}
-              else
-                #{memoized_ivar} = #{original_method}.freeze
-              end
+  module Memoizable #:nodoc:
+    def self.extended(obj)
+      klass = obj.respond_to?(:class_eval) ? obj : obj.metaclass
+      klass.class_eval do
+        def freeze
+          methods.each do |method|
+            if m = method.to_s.match(/^unmemoized_(.*)/)
+              send(m[1])
             end
-          EOS
+          end
+          super
         end
       end
     end
 
-    def freeze
-      methods.each do |method|
-        if m = method.to_s.match(/\Aunmemoized_(.*)/)
-          send(m[1])
-        end
+    def memoize(*symbols)
+      symbols.each do |symbol|
+        original_method = "unmemoized_#{symbol}"
+        memoized_ivar = "@#{symbol}"
+
+        klass = respond_to?(:class_eval) ? self : self.metaclass
+        raise "Already memoized #{symbol}" if klass.instance_methods.map(&:to_s).include?(original_method)
+
+        klass.class_eval <<-EOS, __FILE__, __LINE__
+          alias_method :#{original_method}, :#{symbol}
+          def #{symbol}(reload = false)
+            if !reload && defined? #{memoized_ivar}
+              #{memoized_ivar}
+            else
+              #{memoized_ivar} = #{original_method}.freeze
+            end
+          end
+        EOS
       end
-      super
     end
   end
 end

activesupport/test/memoizable_test.rb

@@ -3,21 +3,24 @@
 uses_mocha 'Memoizable' do
   class MemoizableTest < Test::Unit::TestCase
     class Person
-      include ActiveSupport::Memoizable
+      extend ActiveSupport::Memoizable
 
       def name
         fetch_name_from_floppy
       end
 
+      memoize :name
+
       def age
         nil
       end
 
-      def random
-        rand(0)
+      def counter
+        @counter ||= 0
+        @counter += 1
       end
 
-      memoize :name, :age, :random
+      memoize :age, :counter
 
       private
         def fetch_name_from_floppy
@@ -37,9 +40,9 @@ def test_memoization
     end
 
     def test_reloadable
-      random = @person.random
-      assert_equal random, @person.random
-      assert_not_equal random, @person.random(:reload)
+      counter = @person.counter
+      assert_equal 1, @person.counter
+      assert_equal 2, @person.counter(:reload)
     end
 
     def test_memoized_methods_are_frozen
@@ -58,5 +61,30 @@ def test_memoization_frozen_with_nil_value
     def test_double_memoization
       assert_raise(RuntimeError) { Person.memoize :name }
     end
+
+    class Company
+      def name
+        lookup_name
+      end
+
+      def lookup_name
+        "37signals"
+      end
+    end
+
+    def test_object_memoization
+      company = Company.new
+      company.extend ActiveSupport::Memoizable
+      company.memoize :name
+
+      assert_equal "37signals", company.name
+      # Mocha doesn't play well with frozen objects
+      company.metaclass.instance_eval { define_method(:lookup_name) { b00m } }
+      assert_equal "37signals", company.name
+
+      assert_equal true, company.name.frozen?
+      company.freeze
+      assert_equal true, company.name.frozen?
+    end
   end
 end