1 files changed, 41 insertions, 0 deletions
diff --git a/lib/final.rb b/lib/final.rb
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index 0000000000..cdffd941e7
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+++ b/lib/final.rb
@@ -0,0 +1,41 @@
+#
+# $Id$
+# Copyright (C) 1998 Yukihiro Matsumoto. All rights reserved. 
+
+# The ObjectSpace extension:
+#
+#  ObjectSpace.define_finalizer(obj, proc=lambda())
+#
+#    Defines the finalizer for the specified object.
+#
+#  ObjectSpace.undefine_finalizer(obj)
+#
+#    Removes the finalizers for the object.  If multiple finalizers are
+#    defined for the object,  all finalizers will be removed.
+#
+
+module ObjectSpace
+  Finalizers = {}
+  def define_finalizer(obj, proc=lambda())
+    ObjectSpace.call_finalizer(obj)
+    if assoc = Finalizers[obj.id]
+      assoc.push(proc)
+    else
+      Finalizers[obj.id] = [proc]
+    end
+  end
+  def undefine_finalizer(obj)
+    Finalizers.delete(obj.id)
+  end
+  module_function :define_finalizer, :undefine_finalizer
+
+  Generic_Finalizer = proc {|id|
+    if Finalizers.key? id
+      for proc in Finalizers[id]
+	proc.call(id)
+      end
+      Finalizers.delete(id)
+    end
+  }
+  add_finalizer Generic_Finalizer
+end