Clean up AbstractController::Logger and write documentation

actionpack/lib/action_controller/abstract/logger.rb

@@ -5,6 +5,13 @@ module AbstractController
   module Logger
     extend ActiveSupport::Concern
 
+    # A class that allows you to defer expensive processing
+    # until the logger actually tries to log. Otherwise, you are
+    # forced to do the processing in advance, and send the
+    # entire processed String to the logger, which might
+    # just discard the String if the log level is too low.
+    #
+    # TODO: Require that Rails loggers accept a block.
     class DelayedLog
       def initialize(&blk)
         @blk = blk
@@ -20,8 +27,10 @@ module AbstractController
       cattr_accessor :logger
     end
 
-    def process(action)
-      ret = super
+    # Override process_action in the AbstractController::Base
+    # to log details about the method.
+    def process_action(action)
+      super
 
       if logger
         log = DelayedLog.new do
@@ -32,10 +41,9 @@ module AbstractController
 
         logger.info(log)
       end
-
-      ret
     end
 
+  private
     def request_origin
       # this *needs* to be cached!
       # otherwise you'd get different results if calling it more than once