1 files changed, 106 insertions, 0 deletions
diff --git a/actionpack/lib/action_view/rendering.rb b/actionpack/lib/action_view/rendering.rb
new file mode 100644
index 0000000000..baa5d2c3fd
--- /dev/null
+++ b/actionpack/lib/action_view/rendering.rb
@@ -0,0 +1,106 @@
+require 'active_support/core_ext/object/try'
+
+module ActionView
+  # = Action View Rendering
+  module Rendering
+    # Returns the result of a render that's dictated by the options hash. The primary options are:
+    #
+    # * <tt>:partial</tt> - See ActionView::Partials.
+    # * <tt>:update</tt> - Calls update_page with the block given.
+    # * <tt>:file</tt> - Renders an explicit template file (this used to be the old default), add :locals to pass in those.
+    # * <tt>:inline</tt> - Renders an inline template similar to how it's done in the controller.
+    # * <tt>:text</tt> - Renders the text passed in out.
+    # * <tt>:once</tt> - Accepts a string or an array of strings and Rails will ensure they each of them are rendered just once.
+    #
+    # If no options hash is passed or :update specified, the default is to render a partial and use the second parameter
+    # as the locals hash.
+    def render(options = {}, locals = {}, &block)
+      case options
+      when Hash
+        if block_given?
+          _render_partial(options.merge(:partial => options[:layout]), &block)
+        elsif options.key?(:partial)
+          _render_partial(options)
+        elsif options.key?(:once)
+          _render_once(options)
+        else
+          _render_template(options)
+        end
+      when :update
+        update_page(&block)
+      else
+        _render_partial(:partial => options, :locals => locals)
+      end
+    end
+
+    # Returns the contents that are yielded to a layout, given a name or a block.
+    #
+    # You can think of a layout as a method that is called with a block. If the user calls
+    # <tt>yield :some_name</tt>, the block, by default, returns <tt>content_for(:some_name)</tt>.
+    # If the user calls simply +yield+, the default block returns <tt>content_for(:layout)</tt>.
+    #
+    # The user can override this default by passing a block to the layout:
+    #
+    #   # The template
+    #   <%= render :layout => "my_layout" do %>
+    #     Content
+    #   <% end %>
+    #
+    #   # The layout
+    #   <html>
+    #     <%= yield %>
+    #   </html>
+    #
+    # In this case, instead of the default block, which would return <tt>content_for(:layout)</tt>,
+    # this method returns the block that was passed in to <tt>render :layout</tt>, and the response
+    # would be
+    #
+    #   <html>
+    #     Content
+    #   </html>
+    #
+    # Finally, the block can take block arguments, which can be passed in by +yield+:
+    #
+    #   # The template
+    #   <%= render :layout => "my_layout" do |customer| %>
+    #     Hello <%= customer.name %>
+    #   <% end %>
+    #
+    #   # The layout
+    #   <html>
+    #     <%= yield Struct.new(:name).new("David") %>
+    #   </html>
+    #
+    # In this case, the layout would receive the block passed into <tt>render :layout</tt>,
+    # and the struct specified would be passed into the block as an argument. The result
+    # would be
+    #
+    #   <html>
+    #     Hello David
+    #   </html>
+    #
+    def _layout_for(*args, &block)
+      name = args.first
+
+      if name.is_a?(Symbol)
+        @_content_for[name].html_safe
+      elsif block
+        capture(*args, &block)
+      else
+        @_content_for[:layout].html_safe
+      end
+    end
+
+    def _render_once(options) #:nodoc:
+      _template_renderer.render_once(options)
+    end
+
+    def _render_template(options) #:nodoc:
+      _template_renderer.render(options)
+    end
+
+    def _template_renderer #:nodoc:
+      @_template_renderer ||= TemplateRenderer.new(self)
+    end
+  end
+end