Merge commit 'rails/master'

10 files changed, 455 insertions, 167 deletions

diff --git a/actionpack/lib/action_controller/abstract/base.rb b/actionpack/lib/action_controller/abstract/base.rb
index c3daef8759..a19a236ef7 100644
--- a/actionpack/lib/action_controller/abstract/base.rb
+++ b/actionpack/lib/action_controller/abstract/base.rb
@@ -95,11 +95,6 @@ module AbstractController
     end
 
   private
-    # See AbstractController::Base.action_methods
-    def action_methods
-      self.class.action_methods
-    end
-
     # Returns true if the name can be considered an action. This can
     # be overridden in subclasses to modify the semantics of what
     # can be considered an action.
@@ -110,7 +105,7 @@ module AbstractController
     # ==== Returns
     # TrueClass, FalseClass
     def action_method?(name)
-      action_methods.include?(name)
+      self.class.action_methods.include?(name)
     end
 
     # Call the action. Override this in a subclass to modify the
diff --git a/actionpack/lib/action_controller/abstract/helpers.rb b/actionpack/lib/action_controller/abstract/helpers.rb
index 0a2776de9c..6b73f887c1 100644
--- a/actionpack/lib/action_controller/abstract/helpers.rb
+++ b/actionpack/lib/action_controller/abstract/helpers.rb
@@ -5,33 +5,26 @@ module AbstractController
     include Renderer
 
     included do
-      extlib_inheritable_accessor :master_helper_module
-      self.master_helper_module = Module.new
+      extlib_inheritable_accessor(:_helpers) { Module.new }
     end
 
+    # Override AbstractController::Renderer's _action_view to include the
+    # helper module for this class into its helpers module.
     def _action_view
-      @_action_view ||= begin
-        av = super
-        av.helpers.send(:include, master_helper_module)
-        av
-      end
+      @_action_view ||= super.tap { |av| av.helpers.include(_helpers) }
     end
 
     module ClassMethods
+      # When a class is inherited, wrap its helper module in a new module.
+      # This ensures that the parent class's module can be changed
+      # independently of the child class's.
       def inherited(klass)
-        klass.master_helper_module = Module.new
-        klass.master_helper_module.__send__ :include, master_helper_module
+        helpers = _helpers
+        klass._helpers = Module.new { include helpers }
 
         super
       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.
-      def add_template_helper(mod)
-        master_helper_module.module_eval { include mod }
-      end
-
       # Declare a controller method as a helper. For example, the following
       # makes the +current_user+ controller method available to the view:
       #   class ApplicationController < ActionController::Base
@@ -48,9 +41,13 @@ module AbstractController
       #
       # In a view:
       #  <% if logged_in? -%>Welcome, <%= current_user.name %><% end -%>
+      #
+      # ==== Parameters
+      # meths<Array[#to_s]>:: The name of a method on the controller
+      #   to be made available on the view.
       def helper_method(*meths)
         meths.flatten.each do |meth|
-          master_helper_module.class_eval <<-ruby_eval, __FILE__, __LINE__ + 1
+          _helpers.class_eval <<-ruby_eval, __FILE__, __LINE__ + 1
             def #{meth}(*args, &blk)
               controller.send(%(#{meth}), *args, &blk)
             end
@@ -58,6 +55,14 @@ module AbstractController
         end
       end
 
+      # Make a number of helper modules part of this class' default
+      # helpers.
+      #
+      # ==== Parameters
+      # *args<Array[Module]>:: Modules to be included
+      # block<Block>:: Evalulate the block in the context
+      #   of the helper module. Any methods defined in the block
+      #   will be helpers.
       def helper(*args, &block)
         args.flatten.each do |arg|
           case arg
@@ -65,7 +70,18 @@ module AbstractController
             add_template_helper(arg)
           end
         end
-        master_helper_module.module_eval(&block) if block_given?
+        _helpers.module_eval(&block) if block_given?
+      end
+
+      private
+      # Makes all the (instance) methods in the helper module available to templates
+      # rendered through this controller.
+      #
+      # ==== Parameters
+      # mod<Module>:: The module to include into the current helper module
+      #   for the class
+      def add_template_helper(mod)
+        _helpers.module_eval { include mod }
       end
     end
   end
diff --git a/actionpack/lib/action_controller/abstract/layouts.rb b/actionpack/lib/action_controller/abstract/layouts.rb
index 273063f74b..9ff8e9beb1 100644
--- a/actionpack/lib/action_controller/abstract/layouts.rb
+++ b/actionpack/lib/action_controller/abstract/layouts.rb
@@ -5,16 +5,26 @@ module AbstractController
     include Renderer
 
     included do
-      extlib_inheritable_accessor :_layout_conditions
-      self._layout_conditions = {}
+      extlib_inheritable_accessor(:_layout_conditions) { Hash.new }
     end
 
     module ClassMethods
+      # Specify the layout to use for this class.
+      #
+      # If the specified layout is a:
+      # String:: the String is the template name
+      # Symbol:: call the method specified by the symbol, which will return
+      #   the template name
+      # false::  There is no layout
+      # true::   raise an ArgumentError
+      #
+      # ==== Parameters
+      # layout<String, Symbol, false)>:: The layout to use.
+      #
+      # ==== Options (conditions)
+      # :only<#to_s, Array[#to_s]>:: A list of actions to apply this layout to.
+      # :except<#to_s, Array[#to_s]>:: Apply this layout to all actions but this one
       def layout(layout, conditions = {})
-        unless [String, Symbol, FalseClass, NilClass].include?(layout.class)
-          raise ArgumentError, "Layouts must be specified as a String, Symbol, false, or nil"
-        end
-
         conditions.each {|k, v| conditions[k] = Array(v).map {|a| a.to_s} }
         self._layout_conditions = conditions
 
@@ -22,6 +32,11 @@ module AbstractController
         _write_layout_method
       end
 
+      # If no layout is supplied, look for a template named the return
+      # value of this method.
+      #
+      # ==== Returns
+      # String:: A template name
       def _implied_layout_name
         name.underscore
       end
@@ -29,23 +44,31 @@ module AbstractController
       # Takes the specified layout and creates a _layout method to be called
       # by _default_layout
       #
-      # If the specified layout is a:
-      # String:: return the string
-      # Symbol:: call the method specified by the symbol
-      # false::  return nil
-      # none::   If a layout is found in the view paths with the controller's
-      #          name, return that string. Otherwise, use the superclass'
-      #          layout (which might also be implied)
+      # If there is no explicit layout specified:
+      # If a layout is found in the view paths with the controller's
+      # name, return that string. Otherwise, use the superclass'
+      # layout (which might also be implied)
       def _write_layout_method
         case @_layout
         when String
           self.class_eval %{def _layout(details) #{@_layout.inspect} end}
         when Symbol
-          self.class_eval %{def _layout(details) #{@_layout} end}
+          self.class_eval <<-ruby_eval, __FILE__, __LINE__ + 1
+            def _layout(details)
+              #{@_layout}.tap do |layout|
+                unless layout.is_a?(String) || !layout
+                  raise ArgumentError, "Your layout method :#{@_layout} returned \#{layout}. It " \
+                    "should have returned a String, false, or nil"
+                end
+              end
+            end
+          ruby_eval
         when false
           self.class_eval %{def _layout(details) end}
-        else
-          self.class_eval %{
+        when true
+          raise ArgumentError, "Layouts must be specified as a String, Symbol, false, or nil"
+        when nil
+          self.class_eval <<-ruby_eval, __FILE__, __LINE__ + 1
             def _layout(details)
               if view_paths.find_by_parts?("#{_implied_layout_name}", details, "layouts")
                 "#{_implied_layout_name}"
@@ -53,33 +76,54 @@ module AbstractController
                 super
               end
             end
-          }
+          ruby_eval
         end
       end
     end
 
   private
-    # This will be overwritten
-    def _layout(details)
-    end
+    # This will be overwritten by _write_layout_method
+    def _layout(details) end
 
-    # :api: plugin
-    # ====
-    # Override this to mutate the inbound layout name
+    # Determine the layout for a given name and details.
+    #
+    # ==== Parameters
+    # name<String>:: The name of the template
+    # details<Hash{Symbol => Object}>:: A list of details to restrict
+    #   the lookup to. By default, layout lookup is limited to the
+    #   formats specified for the current request.
     def _layout_for_name(name, details = {:formats => formats})
-      unless [String, FalseClass, NilClass].include?(name.class)
-        raise ArgumentError, "String, false, or nil expected; you passed #{name.inspect}"
-      end
-
-      name && view_paths.find_by_parts(name, details, _layout_prefix(name))
+      name && _find_by_parts(name, details)
     end
 
-    # TODO: Decide if this is the best hook point for the feature
-    def _layout_prefix(name)
-      "layouts"
+    # Take in the name and details and find a Template.
+    #
+    # ==== Parameters
+    # name<String>:: The name of the template to retrieve
+    # details<Hash>:: A list of details to restrict the search by. This
+    #   might include details like the format or locale of the template.
+    #
+    # ==== Returns
+    # Template:: A template object matching the name and details
+    def _find_by_parts(name, details)
+      # TODO: Make prefix actually part of details in ViewPath#find_by_parts
+      prefix = details.key?(:prefix) ? details.delete(:prefix) : "layouts"
+      view_paths.find_by_parts(name, details, prefix)
     end
 
-    def _default_layout(require_layout = false, details = {:formats => formats})
+    # Returns the default layout for this controller and a given set of details. 
+    # Optionally raises an exception if the layout could not be found.
+    #
+    # ==== Parameters
+    # details<Hash>:: A list of details to restrict the search by. This
+    #   might include details like the format or locale of the template.
+    # require_layout<Boolean>:: If this is true, raise an ArgumentError
+    #   with details about the fact that the exception could not be
+    #   found (defaults to false)
+    #
+    # ==== Returns
+    # Template:: The template object for the default layout (or nil)
+    def _default_layout(details, require_layout = false)
       if require_layout && _action_has_layout? && !_layout(details)
         raise ArgumentError,
           "There was no default layout for #{self.class} in #{view_paths.inspect}"
@@ -93,6 +137,12 @@ module AbstractController
       end
     end
 
+    # Determines whether the current action has a layout by checking the
+    # action name against the :only and :except conditions set on the
+    # layout.
+    #
+    # ==== Returns
+    # Boolean:: True if the action has a layout, false otherwise.
     def _action_has_layout?
       conditions = _layout_conditions
       if only = conditions[:only]
diff --git a/actionpack/lib/action_controller/abstract/logger.rb b/actionpack/lib/action_controller/abstract/logger.rb
index d6fa843485..b960e152e3 100644
--- a/actionpack/lib/action_controller/abstract/logger.rb
+++ b/actionpack/lib/action_controller/abstract/logger.rb
@@ -5,6 +5,13 @@ module AbstractController
   module Logger
     extend ActiveSupport::Concern
 
+    # A class that allows you to defer expensive processing
+    # until the logger actually tries to log. Otherwise, you are
+    # forced to do the processing in advance, and send the
+    # entire processed String to the logger, which might
+    # just discard the String if the log level is too low.
+    #
+    # TODO: Require that Rails loggers accept a block.
     class DelayedLog
       def initialize(&blk)
         @blk = blk
@@ -20,8 +27,10 @@ module AbstractController
       cattr_accessor :logger
     end
 
-    def process(action)
-      ret = super
+    # Override process_action in the AbstractController::Base
+    # to log details about the method.
+    def process_action(action)
+      super
 
       if logger
         log = DelayedLog.new do
@@ -32,10 +41,9 @@ module AbstractController
 
         logger.info(log)
       end
-
-      ret
     end
 
+  private
     def request_origin
       # this *needs* to be cached!
       # otherwise you'd get different results if calling it more than once
diff --git a/actionpack/lib/action_controller/abstract/renderer.rb b/actionpack/lib/action_controller/abstract/renderer.rb
index 28bdda4a75..611d3a16ce 100644
--- a/actionpack/lib/action_controller/abstract/renderer.rb
+++ b/actionpack/lib/action_controller/abstract/renderer.rb
@@ -29,6 +29,9 @@ module AbstractController
     #   partial<Boolean>:: Whether or not the template to render is a partial
     # _partial:: If a partial, rather than a template, was rendered, return
     #   the partial.
+    # helpers:: A module containing the helpers to be used in the view. This
+    #   module should respond_to include.
+    # controller:: The controller that initialized the ActionView
     #
     # Override this method in a to change the default behavior.
     def _action_view
diff --git a/actionpack/lib/action_controller/new_base/compatibility.rb b/actionpack/lib/action_controller/new_base/compatibility.rb
index f278c2da14..29ba43a879 100644
--- a/actionpack/lib/action_controller/new_base/compatibility.rb
+++ b/actionpack/lib/action_controller/new_base/compatibility.rb
@@ -114,8 +114,9 @@ module ActionController
       super || (respond_to?(:method_missing) && "_handle_method_missing")
     end
 
-    def _layout_prefix(name)
-      super unless name =~ /\blayouts/
+    def _find_by_parts(name, details)
+      details[:prefix] = nil if name =~ /\blayouts/
+      super
     end
 
     def performed?
diff --git a/actionpack/lib/action_controller/new_base/helpers.rb b/actionpack/lib/action_controller/new_base/helpers.rb
index e8000be87b..2fa5ea6519 100644
--- a/actionpack/lib/action_controller/new_base/helpers.rb
+++ b/actionpack/lib/action_controller/new_base/helpers.rb
@@ -3,6 +3,51 @@ require 'active_support/core_ext/name_error'
 require 'active_support/dependencies'
 
 module ActionController
+  # The Rails framework provides a large number of helpers for working with +assets+, +dates+, +forms+,
+  # +numbers+ and model objects, to name a few. These helpers are available to all templates
+  # by default.
+  #
+  # In addition to using the standard template helpers provided in the Rails framework, creating custom helpers to
+  # extract complicated logic or reusable functionality is strongly encouraged. By default, the controller will
+  # include a helper whose name matches that of the controller, e.g., <tt>MyController</tt> will automatically
+  # include <tt>MyHelper</tt>.
+  #
+  # Additional helpers can be specified using the +helper+ class method in <tt>ActionController::Base</tt> or any
+  # controller which inherits from it.
+  #
+  # ==== Examples
+  # The +to_s+ method from the Time class can be wrapped in a helper method to display a custom message if
+  # the Time object is blank:
+  #
+  #   module FormattedTimeHelper
+  #     def format_time(time, format=:long, blank_message="&nbsp;")
+  #       time.blank? ? blank_message : time.to_s(format)
+  #     end
+  #   end
+  #
+  # FormattedTimeHelper can now be included in a controller, using the +helper+ class method:
+  #
+  #   class EventsController < ActionController::Base
+  #     helper FormattedTimeHelper
+  #     def index
+  #       @events = Event.find(:all)
+  #     end
+  #   end
+  #
+  # Then, in any view rendered by <tt>EventController</tt>, the <tt>format_time</tt> method can be called:
+  #
+  #   <% @events.each do |event| -%>
+  #     <p>
+  #       <% format_time(event.time, :short, "N/A") %> | <%= event.name %>
+  #     </p>
+  #   <% end -%>
+  #
+  # Finally, assuming we have two event instances, one which has a time and one which does not,
+  # the output might look like this:
+  #
+  #   23 Aug 11:30 | Carolina Railhawks Soccer Match
+  #   N/A | Carolina Railhaws Training Workshop
+  #
   module Helpers
     extend ActiveSupport::Concern
 
@@ -10,20 +55,22 @@ module ActionController
 
     included do
       # Set the default directory for helpers
-      class_inheritable_accessor :helpers_dir
-      self.helpers_dir = (defined?(RAILS_ROOT) ? "#{RAILS_ROOT}/app/helpers" : "app/helpers")
+      extlib_inheritable_accessor(:helpers_dir) do
+        defined?(RAILS_ROOT) ? "#{RAILS_ROOT}/app/helpers" : "app/helpers"
+      end
     end
 
     module ClassMethods
       def inherited(klass)
-        klass.__send__ :default_helper_module!
+        klass.class_eval { default_helper_module! unless name.blank? }
         super
       end
 
       # The +helper+ class method can take a series of helper module names, a block, or both.
       #
-      # * <tt>*args</tt>: One or more modules, strings or symbols, or the special symbol <tt>:all</tt>.
-      # * <tt>&block</tt>: A block defining helper methods.
+      # ==== Parameters
+      # *args<Array[Module, Symbol, String, :all]>
+      # block<Block>:: A block defining helper methods
       #
       # ==== Examples
       # When the argument is a string or symbol, the method will provide the "_helper" suffix, require the file
@@ -56,34 +103,7 @@ module ActionController
       #   helper(:three, BlindHelper) { def mice() 'mice' end }
       #
       def helper(*args, &block)
-        args.flatten.each do |arg|
-          case arg
-          when :all
-            helper all_application_helpers
-          when String, Symbol
-            file_name  = arg.to_s.underscore + '_helper'
-            class_name = file_name.camelize
-
-            begin
-              require_dependency(file_name)
-            rescue LoadError => load_error
-              requiree = / -- (.*?)(\.rb)?$/.match(load_error.message).to_a[1]
-              if requiree == file_name
-                msg = "Missing helper file helpers/#{file_name}.rb"
-                raise LoadError.new(msg).copy_blame!(load_error)
-              else
-                raise
-              end
-            end
-
-            super class_name.constantize
-          else
-            super args
-          end
-        end
-
-        # Evaluate block in template class if given.
-        master_helper_module.module_eval(&block) if block_given?
+        super(*_modules_for_helpers(args), &block)
       end
 
       # Declares helper accessors for controller attributes. For example, the
@@ -91,39 +111,68 @@ module ActionController
       # controller and makes them available to the view:
       #   helper_attr :name
       #   attr_accessor :name
+      #
+      # ==== Parameters
+      # *attrs<Array[String, Symbol]>:: Names of attributes to be converted
+      #   into helpers.
       def helper_attr(*attrs)
         attrs.flatten.each { |attr| helper_method(attr, "#{attr}=") }
       end
 
       # 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
-        else
-          @helper_proxy
-        end
+        @helper_proxy ||= ActionView::Base.new.extend(_helpers)
       end
 
-      private
-        def default_helper_module!
-          unless name.blank?
-            module_name = name.sub(/Controller$|$/, 'Helper')
-            module_path = module_name.split('::').map { |m| m.underscore }.join('/')
-            require_dependency module_path
-            helper module_name.constantize
+    private
+      # Returns a list of modules, normalized from the acceptable kinds of
+      # helpers with the following behavior:
+      # String or Symbol:: :FooBar or "FooBar" becomes "foo_bar_helper",
+      #   and "foo_bar_helper.rb" is loaded using require_dependency.
+      # :all:: Loads all modules in the #helpers_dir
+      # Module:: No further processing
+      #
+      # After loading the appropriate files, the corresponding modules
+      # are returned.
+      #
+      # ==== Parameters
+      # args<Array[String, Symbol, Module, all]>:: A list of helpers
+      #
+      # ==== Returns
+      # Array[Module]:: A normalized list of modules for the list of
+      #   helpers provided.
+      def _modules_for_helpers(args)
+        args.flatten.map! do |arg|
+          case arg
+          when :all
+            _modules_for_helpers all_application_helpers
+          when String, Symbol
+            file_name = "#{arg.to_s.underscore}_helper"
+            require_dependency(file_name, "Missing helper file helpers/%s.rb")
+            file_name.camelize.constantize
+          when Module
+            arg
+          else
+            raise ArgumentError, "helper must be a String, Symbol, or Module"
           end
-        rescue MissingSourceFile => e
-          raise unless e.is_missing? module_path
-        rescue NameError => e
-          raise unless e.missing_name? module_name
         end
+      end
 
-        # Extract helper names from files in app/helpers/**/*.rb
-        def all_application_helpers
-          extract = /^#{Regexp.quote(helpers_dir)}\/?(.*)_helper.rb$/
-          Dir["#{helpers_dir}/**/*_helper.rb"].map { |file| file.sub extract, '\1' }
-        end
+      def default_helper_module!
+        module_name = name.sub(/Controller$/, '')
+        module_path = module_name.underscore
+        helper module_path
+      rescue MissingSourceFile => e
+        raise e unless e.is_missing? "#{module_path}_helper"
+      rescue NameError => e
+        raise e unless e.missing_name? "#{module_name}Helper"
+      end
+
+      # Extract helper names from files in app/helpers/**/*.rb
+      def all_application_helpers
+        extract = /^#{Regexp.quote(helpers_dir)}\/?(.*)_helper.rb$/
+        Dir["#{helpers_dir}/**/*_helper.rb"].map { |file| file.sub extract, '\1' }
+      end
     end
   end
 end
diff --git a/actionpack/lib/action_controller/new_base/hide_actions.rb b/actionpack/lib/action_controller/new_base/hide_actions.rb
index b45e520bee..af68c772b1 100644
--- a/actionpack/lib/action_controller/new_base/hide_actions.rb
+++ b/actionpack/lib/action_controller/new_base/hide_actions.rb
@@ -1,39 +1,35 @@
 module ActionController
+  # ActionController::HideActions adds the ability to prevent public methods on a controller
+  # to be called as actions.
   module HideActions
     extend ActiveSupport::Concern
 
     included do
-      extlib_inheritable_accessor :hidden_actions
-      self.hidden_actions ||= Set.new
+      extlib_inheritable_accessor(:hidden_actions) { Set.new }
     end
 
-    def action_methods
-      self.class.action_names
-    end
+  private
 
-    def action_names
-      action_methods
+    # Overrides AbstractController::Base#action_method? to return false if the
+    # action name is in the list of hidden actions.
+    def action_method?(action_name)
+      !hidden_actions.include?(action_name) && super
     end
 
-    private
-      def action_method?(action_name)
-        !hidden_actions.include?(action_name) && super
+    module ClassMethods
+      # Sets all of the actions passed in as hidden actions.
+      #
+      # ==== Parameters
+      # *args<#to_s>:: A list of actions
+      def hide_action(*args)
+        hidden_actions.merge(args.map! {|a| a.to_s })
       end
 
-      module ClassMethods
-        def hide_action(*args)
-          args.each do |arg|
-            self.hidden_actions << arg.to_s
-          end
-        end
-
-        def action_methods
-          @action_names ||= Set.new(super.reject {|name| self.hidden_actions.include?(name.to_s)})
-        end
-
-        def self.action_names
-          action_methods
-        end
+      # Overrides AbstractController::Base#action_methods to remove any methods
+      # that are listed as hidden methods.
+      def action_methods
+        @action_methods ||= Set.new(super.reject {|name| hidden_actions.include?(name)})
       end
+    end
   end
 end
diff --git a/actionpack/lib/action_controller/new_base/http.rb b/actionpack/lib/action_controller/new_base/http.rb
index c96aaaa865..2e73561f93 100644
--- a/actionpack/lib/action_controller/new_base/http.rb
+++ b/actionpack/lib/action_controller/new_base/http.rb
@@ -2,48 +2,48 @@ require 'action_controller/abstract'
 require 'active_support/core_ext/module/delegation'
 
 module ActionController
+  # ActionController::Http provides a way to get a valid Rack application from a controller.
+  #
+  # In AbstractController, dispatching is triggered directly by calling #process on a new controller.
+  # ActionController::Http provides an #action method that returns a valid Rack application for a
+  # given action. Other rack builders, such as Rack::Builder, Rack::URLMap, and the Rails router,
+  # can dispatch directly to the action returned by FooController.action(:index).
   class Http < AbstractController::Base
     abstract!
 
     # :api: public
     attr_internal :params, :env
 
-    # :api: public
+    # Returns the last part of the controller's name, underscored, without the ending
+    # "Controller". For instance, MyApp::MyPostsController would return "my_posts" for
+    # controller_name
+    #
+    # ==== Returns
+    # String
     def self.controller_name
       @controller_name ||= controller_path.split("/").last
     end
 
-    # :api: public
+    # Delegates to the class' #controller_name
     def controller_name
       self.class.controller_name
     end
 
-    # :api: public
+    # Returns the full controller name, underscored, without the ending Controller.
+    # For instance, MyApp::MyPostsController would return "my_app/my_posts" for
+    # controller_name.
+    #
+    # ==== Returns
+    # String
     def self.controller_path
       @controller_path ||= self.name.sub(/Controller$/, '').underscore
     end
 
-    # :api: public
+    # Delegates to the class' #controller_path
     def controller_path
       self.class.controller_path
     end
 
-    # :api: private
-    def self.action_names
-      action_methods
-    end
-
-    # :api: private
-    def action_names
-      action_methods
-    end
-
-    # :api: plugin
-    def self.call(env)
-      controller = new
-      controller.call(env).to_rack
-    end
-
     # The details below can be overridden to support a specific
     # Request and Response object. The default ActionController::Base
     # implementation includes RackConvenience, which makes a request
@@ -57,7 +57,7 @@ module ActionController
       super
     end
 
-    # Basic implements for content_type=, location=, and headers are
+    # Basic implementations for content_type=, location=, and headers are
     # provided to reduce the dependency on the RackConvenience module
     # in Renderer and Redirector.
 
@@ -81,6 +81,15 @@ module ActionController
       [status, headers, response_body]
     end
 
+    # Return a rack endpoint for the given action. Memoize the endpoint, so
+    # multiple calls into MyController.action will return the same object
+    # for the same action.
+    #
+    # ==== Parameters
+    # action<#to_s>:: An action name
+    #
+    # ==== Returns
+    # Proc:: A rack application
     def self.action(name)
       @actions ||= {}
       @actions[name.to_s] ||= proc do |env|
diff --git a/actionpack/lib/action_controller/new_base/layouts.rb b/actionpack/lib/action_controller/new_base/layouts.rb
index 0ff71587d6..ace4b148c9 100644
--- a/actionpack/lib/action_controller/new_base/layouts.rb
+++ b/actionpack/lib/action_controller/new_base/layouts.rb
@@ -1,4 +1,163 @@
 module ActionController
+  # Layouts reverse the common pattern of including shared headers and footers in many templates to isolate changes in
+  # repeated setups. The inclusion pattern has pages that look like this:
+  #
+  #   <%= render "shared/header" %>
+  #   Hello World
+  #   <%= render "shared/footer" %>
+  #
+  # This approach is a decent way of keeping common structures isolated from the changing content, but it's verbose
+  # and if you ever want to change the structure of these two includes, you'll have to change all the templates.
+  #
+  # With layouts, you can flip it around and have the common structure know where to insert changing content. This means
+  # that the header and footer are only mentioned in one place, like this:
+  #
+  #   // The header part of this layout
+  #   <%= yield %>
+  #   // The footer part of this layout
+  #
+  # And then you have content pages that look like this:
+  #
+  #    hello world
+  #
+  # At rendering time, the content page is computed and then inserted in the layout, like this:
+  #
+  #   // The header part of this layout
+  #   hello world
+  #   // The footer part of this layout
+  #
+  # NOTE: The old notation for rendering the view from a layout was to expose the magic <tt>@content_for_layout</tt> instance
+  # variable. The preferred notation now is to use <tt>yield</tt>, as documented above.
+  #
+  # == Accessing shared variables
+  #
+  # Layouts have access to variables specified in the content pages and vice versa. This allows you to have layouts with
+  # references that won't materialize before rendering time:
+  #
+  #   <h1><%= @page_title %></h1>
+  #   <%= yield %>
+  #
+  # ...and content pages that fulfill these references _at_ rendering time:
+  #
+  #    <% @page_title = "Welcome" %>
+  #    Off-world colonies offers you a chance to start a new life
+  #
+  # The result after rendering is:
+  #
+  #   <h1>Welcome</h1>
+  #   Off-world colonies offers you a chance to start a new life
+  #
+  # == Layout assignment
+  #
+  # You can either specify a layout declaratively (using the #layout class method) or give
+  # it the same name as your controller, and place it in <tt>app/views/layouts</tt>.
+  # If a subclass does not have a layout specified, it inherits its layout using normal Ruby inheritance.
+  #
+  # For instance, if you have PostsController and a template named <tt>app/views/layouts/posts.html.erb</tt>,
+  # that template will be used for all actions in PostsController and controllers inheriting
+  # from PostsController.
+  #
+  # If you use a module, for instance Weblog::PostsController, you will need a template named
+  # <tt>app/views/layouts/weblog/posts.html.erb</tt>.
+  #
+  # Since all your controllers inherit from ApplicationController, they will use
+  # <tt>app/views/layouts/application.html.erb</tt> if no other layout is specified
+  # or provided.
+  #
+  # == Inheritance Examples
+  #
+  #   class BankController < ActionController::Base
+  #     layout "bank_standard"
+  #
+  #   class InformationController < BankController
+  #
+  #   class TellerController < BankController
+  #     # teller.html.erb exists
+  #
+  #   class TillController < TellerController
+  #
+  #   class VaultController < BankController
+  #     layout :access_level_layout
+  #
+  #   class EmployeeController < BankController
+  #     layout nil
+  #
+  # The InformationController uses "bank_standard" inherited from the BankController, the VaultController overwrites
+  # and picks the layout dynamically, and the EmployeeController doesn't want to use a layout at all.
+  #
+  # The TellerController uses +teller.html.erb+, and TillController inherits that layout and
+  # uses it as well.
+  #
+  # == Types of layouts
+  #
+  # Layouts are basically just regular templates, but the name of this template needs not be specified statically. Sometimes
+  # you want to alternate layouts depending on runtime information, such as whether someone is logged in or not. This can
+  # be done either by specifying a method reference as a symbol or using an inline method (as a proc).
+  #
+  # The method reference is the preferred approach to variable layouts and is used like this:
+  #
+  #   class WeblogController < ActionController::Base
+  #     layout :writers_and_readers
+  #
+  #     def index
+  #       # fetching posts
+  #     end
+  #
+  #     private
+  #       def writers_and_readers
+  #         logged_in? ? "writer_layout" : "reader_layout"
+  #       end
+  #
+  # Now when a new request for the index action is processed, the layout will vary depending on whether the person accessing
+  # is logged in or not.
+  #
+  # If you want to use an inline method, such as a proc, do something like this:
+  #
+  #   class WeblogController < ActionController::Base
+  #     layout proc{ |controller| controller.logged_in? ? "writer_layout" : "reader_layout" }
+  #
+  # Of course, the most common way of specifying a layout is still just as a plain template name:
+  #
+  #   class WeblogController < ActionController::Base
+  #     layout "weblog_standard"
+  #
+  # If no directory is specified for the template name, the template will by default be looked for in <tt>app/views/layouts/</tt>.
+  # Otherwise, it will be looked up relative to the template root.
+  #
+  # == Conditional layouts
+  #
+  # If you have a layout that by default is applied to all the actions of a controller, you still have the option of rendering
+  # a given action or set of actions without a layout, or restricting a layout to only a single action or a set of actions. The
+  # <tt>:only</tt> and <tt>:except</tt> options can be passed to the layout call. For example:
+  #
+  #   class WeblogController < ActionController::Base
+  #     layout "weblog_standard", :except => :rss
+  #
+  #     # ...
+  #
+  #   end
+  #
+  # This will assign "weblog_standard" as the WeblogController's layout  except for the +rss+ action, which will not wrap a layout
+  # around the rendered view.
+  #
+  # Both the <tt>:only</tt> and <tt>:except</tt> condition can accept an arbitrary number of method references, so
+  # #<tt>:except => [ :rss, :text_only ]</tt> is valid, as is <tt>:except => :rss</tt>.
+  #
+  # == Using a different layout in the action render call
+  #
+  # If most of your actions use the same layout, it makes perfect sense to define a controller-wide layout as described above.
+  # Sometimes you'll have exceptions where one action wants to use a different layout than the rest of the controller.
+  # You can do this by passing a <tt>:layout</tt> option to the <tt>render</tt> call. For example:
+  #
+  #   class WeblogController < ActionController::Base
+  #     layout "weblog_standard"
+  #
+  #     def help
+  #       render :action => "help", :layout => "help"
+  #     end
+  #   end
+  #
+  # This will render the help action with the "help" layout instead of the controller-wide "weblog_standard" layout.
   module Layouts
     extend ActiveSupport::Concern
 
@@ -6,6 +165,7 @@ module ActionController
     include AbstractController::Layouts
 
     module ClassMethods
+      # If no layout is provided, look for a layout with this name.
       def _implied_layout_name
         controller_path
       end
@@ -14,16 +174,17 @@ module ActionController
     private
       def _determine_template(options)
         super
-        if (!options.key?(:text) && !options.key?(:inline) && !options.key?(:partial)) || options.key?(:layout)
-          options[:_layout] = _layout_for_option(options.key?(:layout) ? options[:layout] : :none, options[:_template].details)
-        end
+
+        return if (options.key?(:text) || options.key?(:inline) || options.key?(:partial)) && !options.key?(:layout)
+        layout = options.key?(:layout) ? options[:layout] : :none
+        options[:_layout] = _layout_for_option(layout, options[:_template].details)
       end
 
       def _layout_for_option(name, details)
         case name
         when String     then _layout_for_name(name, details)
-        when true       then _default_layout(true, details)
-        when :none      then _default_layout(false, details)
+        when true       then _default_layout(details, true)
+        when :none      then _default_layout(details, false)
         when false, nil then nil
         else
           raise ArgumentError,