1/*
2 * Copyright (C) 2013 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 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef WeakObjCPtr_h
27#define WeakObjCPtr_h
28
29#include <objc/runtime.h>
30#include <type_traits>
31#include <wtf/RetainPtr.h>
32
33#if __has_include(<objc/objc-internal.h>)
34#include <objc/objc-internal.h>
35#else
36extern "C" {
37id objc_loadWeakRetained(id*);
38id objc_initWeak(id*, id);
39void objc_destroyWeak(id*);
40}
41#endif
42
43namespace WebKit {
44
45template<typename T> class WeakObjCPtr {
46public:
47    typedef typename std::remove_pointer<T>::type ValueType;
48
49    WeakObjCPtr()
50        : m_weakReference(nullptr)
51    {
52    }
53
54    WeakObjCPtr(ValueType *ptr)
55    {
56        objc_initWeak(&m_weakReference, ptr);
57    }
58
59    ~WeakObjCPtr()
60    {
61        objc_destroyWeak(&m_weakReference);
62    }
63
64    WeakObjCPtr& operator=(ValueType *ptr)
65    {
66        objc_storeWeak(&m_weakReference, ptr);
67
68        return *this;
69    }
70
71    RetainPtr<ValueType> get() const
72    {
73        return adoptNS(objc_loadWeakRetained(const_cast<id*>(&m_weakReference)));
74    }
75
76    ValueType *getAutoreleased() const
77    {
78        return static_cast<ValueType *>(objc_loadWeak(const_cast<id*>(&m_weakReference)));
79    }
80
81private:
82    id m_weakReference;
83};
84
85} // namespace WebKit
86
87#endif // WeakObjCPtr_h
88