JavaScriptCore-903.tar.gz

[apple/javascriptcore.git] / wtf / PassTraits.h

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+/*
+ * Copyright (C) 2011 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.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "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 OR ITS 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 WTF_PassTraits_h
+#define WTF_PassTraits_h
+
+#include "OwnPtr.h"
+#include "RefPtr.h"
+
+// The PassTraits template exists to help optimize (or make possible) use
+// of WTF data structures with WTF smart pointers that have a Pass
+// variant for transfer of ownership
+
+namespace WTF {
+
+template<typename T> struct PassTraits {
+    typedef T Type;
+    typedef T PassType;
+    static PassType transfer(Type& value) { return value; }
+};
+
+template<typename T> struct PassTraits<OwnPtr<T> > {
+    typedef OwnPtr<T> Type;
+    typedef PassOwnPtr<T> PassType;
+    static PassType transfer(Type& value) { return value.release(); }
+};
+
+template<typename T> struct PassTraits<RefPtr<T> > {
+    typedef RefPtr<T> Type;
+    typedef PassRefPtr<T> PassType;
+    static PassType transfer(Type& value) { return value.release(); }
+};
+
+} // namespace WTF
+
+using WTF::PassTraits;
+
+#endif // WTF_PassTraits_h