module ActionView module Layouts # You can think of a layout as a method that is called with a block. _layout_for # returns the contents that are yielded to the layout. If the user calls yield # :some_name, the block, by default, returns content_for(:some_name). If the user # calls yield, the default block returns content_for(:layout). # # The user can override this default by passing a block to the layout. # # ==== Example # # # The template # <%= render :layout => "my_layout" do %>Content<% end %> # # # The layout # <% yield %> # # In this case, instead of the default block, which would return content_for(:layout), # this method returns the block that was passed in to render layout, and the response # would be Content. # # Finally, the block can take block arguments, which can be passed in by yield. # # ==== Example # # # The template # <%= render :layout => "my_layout" do |customer| %>Hello <%= customer.name %><% end %> # # # The layout # <% yield Struct.new(:name).new("David") %> # # In this case, the layout would receive the block passed into render :layout, # and the Struct specified in the layout would be passed into the block. The result # would be Hello David. def _layout_for(name = nil, &block) #:nodoc: if !block || name @_content_for[name || :layout] else capture(&block) end end # This is the method which actually finds the layout using details in the lookup # context object. If no layout is found, it checkes if at least a layout with # the given name exists across all details before raising the error. # # If self.formats contains several formats, just the first one is considered in # the layout lookup. def find_layout(layout) begin if formats.size == 1 _find_layout(layout) else update_details(:formats => self.formats.first){ _find_layout(layout) } end rescue ActionView::MissingTemplate => e update_details(:formats => nil) do raise unless template_exists?(layout) end end end def _find_layout(layout) #:nodoc: layout =~ /^\// ? with_fallbacks { find_template(layout) } : find_template(layout) end # Contains the logic that actually renders the layout. def _render_layout(layout, locals, &block) #:nodoc: layout.render(self, locals){ |*name| _layout_for(*name, &block) } end end end