diff options
Diffstat (limited to 'activesupport/lib/active_support/vendor/builder-2.1.2/lib/blankslate.rb')
-rw-r--r-- | activesupport/lib/active_support/vendor/builder-2.1.2/lib/blankslate.rb | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/vendor/builder-2.1.2/lib/blankslate.rb b/activesupport/lib/active_support/vendor/builder-2.1.2/lib/blankslate.rb new file mode 100644 index 0000000000..da6034d9c4 --- /dev/null +++ b/activesupport/lib/active_support/vendor/builder-2.1.2/lib/blankslate.rb @@ -0,0 +1,113 @@ +#!/usr/bin/env ruby +#-- +# Copyright 2004, 2006 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. +#++ + +###################################################################### +# 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 + class << self + + # Hide the method named +name+ in the BlankSlate class. Don't + # hide +instance_eval+ or any method beginning with "__". + def hide(name) + if instance_methods.include?(name.to_s) and + name !~ /^(__|instance_eval)/ + @hidden_methods ||= {} + @hidden_methods[name.to_sym] = instance_method(name) + undef_method name + end + end + + def find_hidden_method(name) + @hidden_methods ||= {} + @hidden_methods[name] || superclass.find_hidden_method(name) + end + + # Redefine a previously hidden method so that it may be called on a blank + # slate object. + def reveal(name) + bound_method = nil + unbound_method = find_hidden_method(name) + fail "Don't know how to reveal method '#{name}'" unless unbound_method + define_method(name) do |*args| + bound_method ||= unbound_method.bind(self) + bound_method.call(*args) + end + end + end + + instance_methods.each { |m| hide(m) } +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 method +# defined after BlankSlate has been loaded. +# +module Kernel + class << self + alias_method :blank_slate_method_added, :method_added + + # Detect method additions to Kernel and remove them in the + # BlankSlate class. + def method_added(name) + result = blank_slate_method_added(name) + return result if self != Kernel + BlankSlate.hide(name) + result + end + end +end + +###################################################################### +# Same as above, except in Object. +# +class Object + class << self + alias_method :blank_slate_method_added, :method_added + + # Detect method additions to Object and remove them in the + # BlankSlate class. + def method_added(name) + result = blank_slate_method_added(name) + return result if self != Object + BlankSlate.hide(name) + result + end + + def find_hidden_method(name) + nil + end + end +end + +###################################################################### +# Also, modules included into Object need to be scanned and have their +# instance methods removed from blank slate. In theory, modules +# included into Kernel would have to be removed as well, but a +# "feature" of Ruby prevents late includes into modules from being +# exposed in the first place. +# +class Module + alias blankslate_original_append_features append_features + def append_features(mod) + result = blankslate_original_append_features(mod) + return result if mod != Object + instance_methods.each do |name| + BlankSlate.hide(name) + end + result + end +end
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