Merged updates from trunk into stable branch

[feedcatcher.git] / vendor / rails / activesupport / lib / active_support / core_ext / class / delegating_attributes.rb

diff --git a/vendor/rails/activesupport/lib/active_support/core_ext/class/delegating_attributes.rb b/vendor/rails/activesupport/lib/active_support/core_ext/class/delegating_attributes.rb
new file mode 100644 (file)
index 0000000..000ccf4
--- /dev/null
+++ b/vendor/rails/activesupport/lib/active_support/core_ext/class/delegating_attributes.rb
@@ -0,0 +1,47 @@
+# These class attributes behave something like the class
+# inheritable accessors.  But instead of copying the hash over at
+# the time the subclass is first defined,  the accessors simply
+# delegate to their superclass unless they have been given a 
+# specific value.  This stops the strange situation where values 
+# set after class definition don't get applied to subclasses.
+class Class
+  def superclass_delegating_reader(*names)
+    class_name_to_stop_searching_on = self.superclass.name.blank? ? "Object" : self.superclass.name
+    names.each do |name|
+      class_eval <<-EOS
+      def self.#{name}                                            # def self.only_reader
+        if defined?(@#{name})                                     #   if defined?(@only_reader)
+          @#{name}                                                #     @only_reader
+        elsif superclass < #{class_name_to_stop_searching_on} &&  #   elsif superclass < Object &&
+              superclass.respond_to?(:#{name})                    #         superclass.respond_to?(:only_reader)
+          superclass.#{name}                                      #     superclass.only_reader
+        end                                                       #   end
+      end                                                         # end
+      def #{name}                                                 # def only_reader
+        self.class.#{name}                                        #   self.class.only_reader
+      end                                                         # end
+      def self.#{name}?                                           # def self.only_reader?
+        !!#{name}                                                 #   !!only_reader
+      end                                                         # end
+      def #{name}?                                                # def only_reader?
+        !!#{name}                                                 #   !!only_reader
+      end                                                         # end
+      EOS
+    end
+  end
+
+  def superclass_delegating_writer(*names)
+    names.each do |name|
+      class_eval <<-EOS
+        def self.#{name}=(value)  # def self.only_writer=(value)
+          @#{name} = value        #   @only_writer = value
+        end                       # end
+      EOS
+    end
+  end
+
+  def superclass_delegating_accessor(*names)
+    superclass_delegating_reader(*names)
+    superclass_delegating_writer(*names)
+  end
+end