gistfile1.txt

    # 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(require_layout = false)
      begin
        if action_has_layout?
          layout_name = _layout
        else
          layout = self.class.instance_variable_get(:@_parent_layout)
          layout_name = layout.is_a?(Proc) layout.call(self) : layout
        end
      rescue NameError => e
        raise NoMethodError,
          "You specified #{@_layout.inspect} as the layout, but no such method was found"
      end

      if require_layout && action_has_layout? && !layout_name
        raise ArgumentError,
          "There was no default layout for #{self.class} in #{view_paths.inspect}"
      end

      layout_name
    end

    def _include_layout?(options)
      (options.keys & [:text, :inline, :partial]).empty? || options.key?(:layout)
    end
  end
end