1 files changed, 53 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/vendor/builder/blankslate.rb b/activesupport/lib/active_support/vendor/builder/blankslate.rb
new file mode 100644
index 0000000000..1408c872cc
--- /dev/null
+++ b/activesupport/lib/active_support/vendor/builder/blankslate.rb
@@ -0,0 +1,53 @@
+#!/usr/bin/env ruby
+#--
+# Copyright 2004 by Jim Weirich (jim@weirichhouse.org).
+# All rights reserved.
+
+# Permission is granted for use, copying, modification, distribution,
+# and distribution of modified versions of this work as long as the
+# above copyright notice is included.
+#++
+
+module Builder #:nodoc:
+
+  # BlankSlate provides an abstract base class with no predefined
+  # methods (except for <tt>\_\_send__</tt> and <tt>\_\_id__</tt>).
+  # BlankSlate is useful as a base class when writing classes that
+  # depend upon <tt>method_missing</tt> (e.g. dynamic proxies).
+  class BlankSlate #:nodoc:
+    class << self
+      def hide(name)
+	      undef_method name if
+	        instance_methods.include?(name.to_s) and
+	        name !~ /^(__|instance_eval)/
+      end
+    end
+
+    instance_methods.each { |m| hide(m) }
+  end
+end
+
+# Since Ruby is very dynamic, methods added to the ancestors of
+# BlankSlate <em>after BlankSlate is defined</em> will show up in the
+# list of available BlankSlate methods.  We handle this by defining a hook in the Object and Kernel classes that will hide any defined 
+module Kernel #:nodoc:
+  class << self
+    alias_method :blank_slate_method_added, :method_added
+    def method_added(name)
+      blank_slate_method_added(name)
+      return if self != Kernel
+      Builder::BlankSlate.hide(name)
+    end
+  end
+end
+
+class Object #:nodoc:
+  class << self
+    alias_method :blank_slate_method_added, :method_added
+    def method_added(name)
+      blank_slate_method_added(name)
+      return  if self != Object
+      Builder::BlankSlate.hide(name)
+    end
+  end
+end