1 /*
2  * Copyright (C) 2011 Apple Inc. All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  *
8  * 1.  Redistributions of source code must retain the above copyright
9  *     notice, this list of conditions and the following disclaimer.
10  * 2.  Redistributions in binary form must reproduce the above copyright
11  *     notice, this list of conditions and the following disclaimer in the
12  *     documentation and/or other materials provided with the distribution.
13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
14  *     its contributors may be used to endorse or promote products derived
15  *     from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #ifndef WTF_PassTraits_h
30 #define WTF_PassTraits_h
31 
32 #include "OwnPtr.h"
33 #include "RefPtr.h"
34 
35 // The PassTraits template exists to help optimize (or make possible) use
36 // of WTF data structures with WTF smart pointers that have a Pass
37 // variant for transfer of ownership
38 
39 namespace WTF {
40 
41 template<typename T> struct PassTraits {
42     typedef T Type;
43     typedef T PassType;
transferPassTraits44     static PassType transfer(Type& value) { return value; }
45 };
46 
47 template<typename T> struct PassTraits<OwnPtr<T> > {
48     typedef OwnPtr<T> Type;
49     typedef PassOwnPtr<T> PassType;
50     static PassType transfer(Type& value) { return value.release(); }
51 };
52 
53 template<typename T> struct PassTraits<RefPtr<T> > {
54     typedef RefPtr<T> Type;
55     typedef PassRefPtr<T> PassType;
56     static PassType transfer(Type& value) { return value.release(); }
57 };
58 
59 } // namespace WTF
60 
61 using WTF::PassTraits;
62 
63 #endif // WTF_PassTraits_h
64