Rebundle Builder 2.1.2 but prefer a newer RubyGem if available.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7828 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 113 insertions, 0 deletions

diff --git a/activesupport/lib/active_support/vendor/builder-2.1.2/blankslate.rb b/activesupport/lib/active_support/vendor/builder-2.1.2/blankslate.rb
new file mode 100644
index 0000000000..da6034d9c4
--- /dev/null
+++ b/activesupport/lib/active_support/vendor/builder-2.1.2/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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