Merge pull request #25 from github/activesupport-concern

Pull in ActiveSupport::Concern

actionpack/lib/action_controller/base.rb

@@ -1273,8 +1273,7 @@ module ActionController #:nodoc:
       end
 
       def initialize_template_class(response)
-        response.template = ActionView::Base.new(self.class.view_paths, {}, self)
-        response.template.helpers.send :include, self.class.master_helper_module
+        response.template = self.class.master_helper_class.new(self.class.view_paths, {}, self)
         response.redirected_to = nil
         @performed_render = @performed_redirect = false
       end

actionpack/lib/action_controller/helpers.rb

@@ -69,6 +69,22 @@ module ActionController #:nodoc:
     #   N/A | Carolina Railhaws Training Workshop
     #
     module ClassMethods
+      # To avoid extending an instance of ActionView::Base with the master_helper_module
+      # every single time we render a view, we're caching a class that has
+      # master_helper_module already included that we can just instantiate.
+      def master_helper_class
+        return @master_helper_class if @master_helper_class
+
+        @master_helper_class = Class.new(ActionView::Base).tap do |klass|
+          klass.send(:include, master_helper_module)
+        end
+      end
+
+      def master_helper_module=(mod)
+        write_inheritable_attribute(:master_helper_module, mod)
+        @master_helper_class = nil
+      end
+
       # Makes all the (instance) methods in the helper module available to templates rendered through this controller.
       # See ActionView::Helpers (link:classes/ActionView/Helpers.html) for more about making your own helper modules
       # available to the templates.
@@ -182,8 +198,7 @@ module ActionController #:nodoc:
       # Provides a proxy to access helpers methods from outside the view.
       def helpers
         unless @helper_proxy
-          @helper_proxy = ActionView::Base.new
-          @helper_proxy.extend master_helper_module
+          @helper_proxy = master_helper_class.new
         else
           @helper_proxy
         end

actionpack/lib/action_view/base.rb

@@ -203,24 +203,10 @@ module ActionView #:nodoc:
       ActionView::PathSet.new(Array(value))
     end
 
-    attr_reader :helpers
-
-    class ProxyModule < Module
-      def initialize(receiver)
-        @receiver = receiver
-      end
-
-      def include(*args)
-        super(*args)
-        @receiver.extend(*args)
-      end
-    end
-
     def initialize(view_paths = [], assigns_for_first_render = {}, controller = nil)#:nodoc:
       @assigns = assigns_for_first_render
       @assigns_added = nil
       @controller = controller
-      @helpers = ProxyModule.new(self)
       self.view_paths = view_paths
 
       @_first_render = nil

actionpack/lib/action_view/test_case.rb

@@ -116,8 +116,7 @@ module ActionView
       end
 
       def _view
-        view = ActionView::Base.new(ActionController::Base.view_paths, _assigns, @controller)
-        view.helpers.include master_helper_module
+        view = self.class.master_helper_class.new(ActionController::Base.view_paths, _assigns, @controller)
         view.output_buffer = self.output_buffer
         view
       end

activesupport/lib/active_support/concern.rb

@@ -0,0 +1,134 @@
+module ActiveSupport
+  # A typical module looks like this:
+  #
+  #   module M
+  #     def self.included(base)
+  #       base.extend ClassMethods
+  #       base.class_eval do
+  #         scope :disabled, -> { where(disabled: true) }
+  #       end
+  #     end
+  #
+  #     module ClassMethods
+  #       ...
+  #     end
+  #   end
+  #
+  # By using <tt>ActiveSupport::Concern</tt> the above module could instead be
+  # written as:
+  #
+  #   require 'active_support/concern'
+  #
+  #   module M
+  #     extend ActiveSupport::Concern
+  #
+  #     included do
+  #       scope :disabled, -> { where(disabled: true) }
+  #     end
+  #
+  #     module ClassMethods
+  #       ...
+  #     end
+  #   end
+  #
+  # Moreover, it gracefully handles module dependencies. Given a +Foo+ module
+  # and a +Bar+ module which depends on the former, we would typically write the
+  # following:
+  #
+  #   module Foo
+  #     def self.included(base)
+  #       base.class_eval do
+  #         def self.method_injected_by_foo
+  #           ...
+  #         end
+  #       end
+  #     end
+  #   end
+  #
+  #   module Bar
+  #     def self.included(base)
+  #       base.method_injected_by_foo
+  #     end
+  #   end
+  #
+  #   class Host
+  #     include Foo # We need to include this dependency for Bar
+  #     include Bar # Bar is the module that Host really needs
+  #   end
+  #
+  # But why should +Host+ care about +Bar+'s dependencies, namely +Foo+? We
+  # could try to hide these from +Host+ directly including +Foo+ in +Bar+:
+  #
+  #   module Bar
+  #     include Foo
+  #     def self.included(base)
+  #       base.method_injected_by_foo
+  #     end
+  #   end
+  #
+  #   class Host
+  #     include Bar
+  #   end
+  #
+  # Unfortunately this won't work, since when +Foo+ is included, its <tt>base</tt>
+  # is the +Bar+ module, not the +Host+ class. With <tt>ActiveSupport::Concern</tt>,
+  # module dependencies are properly resolved:
+  #
+  #   require 'active_support/concern'
+  #
+  #   module Foo
+  #     extend ActiveSupport::Concern
+  #     included do
+  #       def self.method_injected_by_foo
+  #         ...
+  #       end
+  #     end
+  #   end
+  #
+  #   module Bar
+  #     extend ActiveSupport::Concern
+  #     include Foo
+  #
+  #     included do
+  #       self.method_injected_by_foo
+  #     end
+  #   end
+  #
+  #   class Host
+  #     include Bar # works, Bar takes care now of its dependencies
+  #   end
+  module Concern
+    class MultipleIncludedBlocks < StandardError #:nodoc:
+      def initialize
+        super "Cannot define multiple 'included' blocks for a Concern"
+      end
+    end
+
+    def self.extended(base) #:nodoc:
+      base.instance_variable_set(:@_dependencies, [])
+    end
+
+    def append_features(base)
+      if base.instance_variable_defined?(:@_dependencies)
+        base.instance_variable_get(:@_dependencies) << self
+        return false
+      else
+        return false if base < self
+        @_dependencies.each { |dep| base.send(:include, dep) }
+        super
+        base.extend const_get(:ClassMethods) if const_defined?(:ClassMethods)
+        base.class_eval(&@_included_block) if instance_variable_defined?(:@_included_block)
+      end
+    end
+
+    def included(base = nil, &block)
+      if base.nil?
+        raise MultipleIncludedBlocks if instance_variable_defined?(:@_included_block)
+
+        @_included_block = block
+      else
+        super
+      end
+    end
+  end
+end

activesupport/lib/active_support/vendor/builder-2.1.2/blankslate.rb

@@ -1,114 +0,0 @@
-#!/usr/bin/env ruby
-#--
-# Copyright 2004, 2006 by Jim Weirich (jim@weirichhouse.org).
-# All rights reserved.
-
-# Permission is granted for use, copying, modification, distribution,
-# and distribution of modified versions of this work as long as the
-# above copyright notice is included.
-#++
-
-######################################################################
-# BlankSlate provides an abstract base class with no predefined
-# methods (except for <tt>\_\_send__</tt> and <tt>\_\_id__</tt>).
-# BlankSlate is useful as a base class when writing classes that
-# depend upon <tt>method_missing</tt> (e.g. dynamic proxies).
-#
-class BlankSlate
-  class << self
-
-    # Hide the method named +name+ in the BlankSlate class.  Don't
-    # hide +instance_eval+ or any method beginning with "__".
-    def hide(name)
-      if (instance_methods.include?(name) || instance_methods.include?(name.to_sym)) and
-        name !~ /^(__|instance_eval|object_id)/
-        @hidden_methods ||= {}
-        @hidden_methods[name] = instance_method(name)
-        undef_method name
-      end
-    end
-
-    def find_hidden_method(name)
-      @hidden_methods ||= {}
-      @hidden_methods[name] || superclass.find_hidden_method(name)
-    end
-
-    # Redefine a previously hidden method so that it may be called on a blank
-    # slate object.
-    def reveal(name)
-      bound_method = nil
-      
-      unbound_method = find_hidden_method(name)
-      fail "Don't know how to reveal method '#{name}'" unless unbound_method
-      define_method(name) do |*args|
-        bound_method ||= unbound_method.bind(self)
-        bound_method.call(*args)
-      end
-    end
-  end
-
-  instance_methods.each { |m| hide(m) }
-end
-
-######################################################################
-# Since Ruby is very dynamic, methods added to the ancestors of
-# BlankSlate <em>after BlankSlate is defined</em> will show up in the
-# list of available BlankSlate methods.  We handle this by defining a
-# hook in the Object and Kernel classes that will hide any method
-# defined after BlankSlate has been loaded.
-#
-module Kernel
-  class << self
-    alias_method :blank_slate_method_added, :method_added
-
-    # Detect method additions to Kernel and remove them in the
-    # BlankSlate class.
-    def method_added(name)
-      result = blank_slate_method_added(name)
-      return result if self != Kernel
-      BlankSlate.hide(name)
-      result
-    end
-  end
-end
-
-######################################################################
-# Same as above, except in Object.
-#
-class Object
-  class << self
-    alias_method :blank_slate_method_added, :method_added
-
-    # Detect method additions to Object and remove them in the
-    # BlankSlate class.
-    def method_added(name)
-      result = blank_slate_method_added(name)
-      return result if self != Object
-      BlankSlate.hide(name)
-      result
-    end
-
-    def find_hidden_method(name)
-      nil
-    end
-  end
-end
-
-######################################################################
-# Also, modules included into Object need to be scanned and have their
-# instance methods removed from blank slate.  In theory, modules
-# included into Kernel would have to be removed as well, but a
-# "feature" of Ruby prevents late includes into modules from being
-# exposed in the first place.
-#
-class Module
-  alias blankslate_original_append_features append_features
-  def append_features(mod)
-    result = blankslate_original_append_features(mod)
-    return result if mod != Object
-    instance_methods.each do |name|
-      BlankSlate.hide(name)
-    end
-    result
-  end
-end

activesupport/lib/active_support/vendor/builder-2.1.2/builder/blankslate.rb

@@ -1,20 +0,0 @@
-#!/usr/bin/env ruby
-#--
-# Copyright 2004, 2006 by Jim Weirich (jim@weirichhouse.org).
-# All rights reserved.
-
-# Permission is granted for use, copying, modification, distribution,
-# and distribution of modified versions of this work as long as the
-# above copyright notice is included.
-#++
-
-require 'blankslate'
-
-######################################################################
-# BlankSlate has been promoted to a top level name and is now
-# available as a standalone gem.  We make the name available in the
-# Builder namespace for compatibility.
-#
-module Builder
-  BlankSlate = ::BlankSlate
-end

activesupport/lib/active_support/vendor/builder-2.1.2/builder/css.rb

@@ -18,8 +18,6 @@
 # Style Sheets (CSS).
 
 
-require 'builder/blankslate'
-
 module Builder
 
   # Create a Cascading Style Sheet (CSS) using Ruby.
@@ -89,7 +87,7 @@ module Builder
   #     background:       red;
   #   }
   #
-  class CSS < BlankSlate
+  class CSS < BasicObject
 
     # Create a CSS builder.
     #
@@ -155,7 +153,7 @@ module Builder
 
     def group!(*args, &block)
       args.each do |arg|
-        if arg.is_a?(Symbol)
+        if arg.is_a?(::Symbol)
           instance_eval(&@library[arg])
         else
           instance_eval(&arg)
@@ -169,7 +167,7 @@ module Builder
     end
 
     def method_missing(sym, *args, &block)
-      sym = "#{sym}:#{args.shift}" if args.first.kind_of?(Symbol)
+      sym = "#{sym}:#{args.shift}" if args.first.kind_of?(::Symbol)
       if block
         _start_container(sym, args.first)
         _css_block(block)

activesupport/lib/active_support/vendor/builder-2.1.2/builder/xmlbase.rb

@@ -1,7 +1,5 @@
 #!/usr/bin/env ruby
 
-require 'builder/blankslate'
-
 module Builder
 
   # Generic error for builder
@@ -9,7 +7,7 @@ module Builder
 
   # XmlBase is a base class for building XML builders.  See
   # Builder::XmlMarkup and Builder::XmlEvents for examples.
-  class XmlBase < BlankSlate
+  class XmlBase < BasicObject
 
     # Create an XML markup builder.
     #
@@ -37,10 +35,10 @@ module Builder
     def method_missing(sym, *args, &block)
       text = nil
       attrs = nil
-      sym = "#{sym}:#{args.shift}" if args.first.kind_of?(Symbol)
+      sym = "#{sym}:#{args.shift}" if args.first.kind_of?(::Symbol)
       args.each do |arg|
         case arg
-        when Hash
+        when ::Hash
           attrs ||= {}
           attrs.merge!(arg)
         else
@@ -50,7 +48,7 @@ module Builder
       end
       if block
         unless text.nil?
-          raise ArgumentError, "XmlMarkup cannot mix a text argument with a block"
+          raise ::ArgumentError, "XmlMarkup cannot mix a text argument with a block"
         end
         _indent
         _start_tag(sym, attrs)

activesupport/lib/active_support/vendor/builder-2.1.2/builder/xmlmarkup.rb

@@ -195,7 +195,7 @@ module Builder
     end
 
     def comment!(comment_text)
-      _ensure_no_block block_given?
+      _ensure_no_block ::Kernel.block_given?
       _special("<!-- ", " -->", comment_text, nil)
     end
 
@@ -210,13 +210,13 @@ module Builder
       @target << "<!#{inst}"
       args.each do |arg|
         case arg
-        when String
+        when ::String
           @target << %{ "#{arg}"} # " WART
-        when Symbol
+        when ::Symbol
           @target << " #{arg}"
         end
       end
-      if block_given?
+      if ::Kernel.block_given?
         @target << " ["
         _newline
         _nested_structures(block)
@@ -236,7 +236,7 @@ module Builder
     #        #=> <?aaa bbb="ccc"?>
     #
     def instruct!(directive_tag=:xml, attrs={})
-      _ensure_no_block block_given?
+      _ensure_no_block ::Kernel.block_given?
       if directive_tag == :xml
         a = { :version=>"1.0", :encoding=>"UTF-8" }
         attrs = a.merge attrs
@@ -257,7 +257,7 @@ module Builder
     #        #=> <![CDATA[text to be included in cdata]]>
     #
     def cdata!(text)
-      _ensure_no_block block_given?
+      _ensure_no_block ::Kernel.block_given?
       _special("<![CDATA[", "]]>", text, nil)
     end
 
@@ -309,7 +309,7 @@ module Builder
 
     def _attr_value(value)
       case value
-      when Symbol
+      when ::Symbol
         value.to_s
       else
         _escape_quote(value.to_s)

activesupport/test/concern_test.rb

@@ -0,0 +1,98 @@
+require 'abstract_unit'
+require 'active_support/concern'
+
+class ConcernTest < ActiveSupport::TestCase
+  module Baz
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      def baz
+        "baz"
+      end
+
+      def included_ran=(value)
+        @@included_ran = value
+      end
+
+      def included_ran
+        @@included_ran
+      end
+    end
+
+    included do
+      self.included_ran = true
+    end
+
+    def baz
+      "baz"
+    end
+  end
+
+  module Bar
+    extend ActiveSupport::Concern
+
+    include Baz
+
+    def bar
+      "bar"
+    end
+
+    def baz
+      "bar+" + super
+    end
+  end
+
+  module Foo
+    extend ActiveSupport::Concern
+
+    include Bar, Baz
+  end
+
+  def setup
+    @klass = Class.new
+  end
+
+  def test_module_is_included_normally
+    @klass.send(:include, Baz)
+    assert_equal "baz", @klass.new.baz
+    assert @klass.included_modules.include?(ConcernTest::Baz)
+  end
+
+  def test_class_methods_are_extended
+    @klass.send(:include, Baz)
+    assert_equal "baz", @klass.baz
+    assert_equal ConcernTest::Baz::ClassMethods, (class << @klass; self.included_modules; end)[0]
+  end
+
+  def test_included_block_is_ran
+    @klass.send(:include, Baz)
+    assert_equal true, @klass.included_ran
+  end
+
+  def test_modules_dependencies_are_met
+    @klass.send(:include, Bar)
+    assert_equal "bar", @klass.new.bar
+    assert_equal "bar+baz", @klass.new.baz
+    assert_equal "baz", @klass.baz
+    assert @klass.included_modules.include?(ConcernTest::Bar)
+  end
+
+  def test_dependencies_with_multiple_modules
+    @klass.send(:include, Foo)
+    assert_equal [ConcernTest::Foo, ConcernTest::Bar, ConcernTest::Baz], @klass.included_modules[0..2]
+  end
+
+  def test_raise_on_multiple_included_calls
+    assert_raises(ActiveSupport::Concern::MultipleIncludedBlocks) do
+      Module.new do
+        extend ActiveSupport::Concern
+
+        included do
+        end
+
+        included do
+        end
+      end
+    end
+  end
+end