More perf work:

  * Move #set_cookie and #delete_cookie inline to optimize. These optimizations should
    almost certainly be sent back upstream to Rack. The optimization involves using
    an ivar for cookies instead of indexing into the headers each time.
  * Was able to use a bare Hash for headers now that cookies have their own joining
    semantics (some code assumed that the raw cookies were an Array).
  * Cache blankness of body on body=
  * Improve expand_cache_key for Arrays of a single element (common in our case)
  * Use a simple layout condition check unless conditions are used
  * Cache visible actions
  * Lazily load the UrlRewriter
  * Make etag an ivar that is set on prepare!

1 files changed, 32 insertions, 17 deletions

diff --git a/actionpack/lib/abstract_controller/layouts.rb b/actionpack/lib/abstract_controller/layouts.rb
index d7317b415c..ac2154dffc 100644
--- a/actionpack/lib/abstract_controller/layouts.rb
+++ b/actionpack/lib/abstract_controller/layouts.rb
@@ -6,17 +6,21 @@ module AbstractController
 
     included do
       extlib_inheritable_accessor(:_layout_conditions) { Hash.new }
+      extlib_inheritable_accessor(:_action_has_layout) { Hash.new }
       _write_layout_method
     end
 
     module ClassMethods
       def inherited(klass)
         super
-        klass._write_layout_method
+        klass.class_eval do
+          _write_layout_method
+          @found_layouts = {}
+        end
       end
 
       def cache_layout(details)
-        layout = @found_layouts ||= {}
+        layout = @found_layouts
         values = details.values_at(:formats, :locale)
 
         # Cache nil
@@ -27,6 +31,28 @@ module AbstractController
         end
       end
 
+      # This module is mixed in if layout conditions are provided. This means
+      # that if no layout conditions are used, this method is not used
+      module LayoutConditions
+        # 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]
+            only.include?(action_name)
+          elsif except = conditions[:except]
+            !except.include?(action_name)
+          else
+            true
+          end
+        end
+      end
+
       # Specify the layout to use for this class.
       #
       # If the specified layout is a:
@@ -43,6 +69,8 @@ module AbstractController
       # :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 = {})
+        include LayoutConditions unless conditions.empty?
+
         conditions.each {|k, v| conditions[k] = Array(v).map {|a| a.to_s} }
         self._layout_conditions = conditions
 
@@ -150,7 +178,7 @@ module AbstractController
       view_paths.find(name, details, prefix)
     end
 
-    # Returns the default layout for this controller and a given set of details. 
+    # 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
@@ -176,21 +204,8 @@ 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]
-        only.include?(action_name)
-      elsif except = conditions[:except]
-        !except.include?(action_name)
-      else
-        true
-      end
+      true
     end
   end
 end