1 files changed, 47 insertions, 0 deletions
diff --git a/actionview/lib/action_view/renderer/abstract_renderer.rb b/actionview/lib/action_view/renderer/abstract_renderer.rb
new file mode 100644
index 0000000000..73c19a0ae2
--- /dev/null
+++ b/actionview/lib/action_view/renderer/abstract_renderer.rb
@@ -0,0 +1,47 @@
+module ActionView
+  # This class defines the interface for a renderer. Each class that
+  # subclasses +AbstractRenderer+ is used by the base +Renderer+ class to
+  # render a specific type of object.
+  #
+  # The base +Renderer+ class uses its +render+ method to delegate to the
+  # renderers. These currently consist of
+  #
+  #   PartialRenderer - Used for rendering partials
+  #   TemplateRenderer - Used for rendering other types of templates
+  #   StreamingTemplateRenderer - Used for streaming
+  #
+  # Whenever the +render+ method is called on the base +Renderer+ class, a new
+  # renderer object of the correct type is created, and the +render+ method on
+  # that new object is called in turn. This abstracts the setup and rendering
+  # into a separate classes for partials and templates.
+  class AbstractRenderer #:nodoc:
+    delegate :find_template, :template_exists?, :with_fallbacks, :with_layout_format, :formats, :to => :@lookup_context
+
+    def initialize(lookup_context)
+      @lookup_context = lookup_context
+    end
+
+    def render
+      raise NotImplementedError
+    end
+
+    protected
+
+    def extract_details(options)
+      @lookup_context.registered_details.each_with_object({}) do |key, details|
+        next unless value = options[key]
+        details[key] = Array(value)
+      end
+    end
+
+    def instrument(name, options={})
+      ActiveSupport::Notifications.instrument("render_#{name}.action_view", options){ yield }
+    end
+
+    def prepend_formats(formats)
+      formats = Array(formats)
+      return if formats.empty? || @lookup_context.html_fallback_for_js
+      @lookup_context.formats = formats | @lookup_context.formats
+    end
+  end
+end