--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/JavaScriptCore/wtf/PossiblyNull.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2009 Apple Inc. All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef PossiblyNull_h
+#define PossiblyNull_h
+
+#include "Assertions.h"
+
+namespace WTF {
+
+template <typename T> struct PossiblyNull {
+    PossiblyNull(T data)
+        : m_data(data)
+    {
+    }
+    PossiblyNull(const PossiblyNull<T>& source)
+        : m_data(source.m_data)
+    {
+        source.m_data = 0;
+    }
+    ~PossiblyNull() { ASSERT(!m_data); }
+    bool getValue(T& out) WARN_UNUSED_RETURN;
+private:
+    mutable T m_data;
+};
+
+template <typename T> bool PossiblyNull<T>::getValue(T& out)
+{
+    out = m_data;
+    bool result = !!m_data;
+    m_data = 0;
+    return result;
+}
+
+}
+
+#endif