1/*
2 * Copyright (C) 2012 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 WeakImpl_h
27#define WeakImpl_h
28
29#include "JSCJSValue.h"
30
31namespace JSC {
32
33class WeakHandleOwner;
34
35class WeakImpl {
36public:
37 enum State {
38 Live = 0x0,
39 Dead = 0x1,
40 Finalized = 0x2,
41 Deallocated = 0x3
42 };
43
44 enum {
45 StateMask = 0x3
46 };
47
48 WeakImpl();
49 WeakImpl(JSValue, WeakHandleOwner*, void* context);
50
51 State state();
52 void setState(State);
53
54 const JSValue& jsValue();
55 WeakHandleOwner* weakHandleOwner();
56 void* context();
57
58 static WeakImpl* asWeakImpl(JSValue*);
59
60private:
61 const JSValue m_jsValue;
62 WeakHandleOwner* m_weakHandleOwner;
63 void* m_context;
64};
65
66inline WeakImpl::WeakImpl()
67 : m_weakHandleOwner(0)
68 , m_context(0)
69{
70 setState(Deallocated);
71}
72
73inline WeakImpl::WeakImpl(JSValue jsValue, WeakHandleOwner* weakHandleOwner, void* context)
74 : m_jsValue(jsValue)
75 , m_weakHandleOwner(weakHandleOwner)
76 , m_context(context)
77{
78 ASSERT(state() == Live);
79 ASSERT(m_jsValue && m_jsValue.isCell());
80}
81
82inline WeakImpl::State WeakImpl::state()
83{
84 return static_cast<State>(reinterpret_cast<uintptr_t>(m_weakHandleOwner) & StateMask);
85}
86
87inline void WeakImpl::setState(WeakImpl::State state)
88{
89 ASSERT(state >= this->state());
90 m_weakHandleOwner = reinterpret_cast<WeakHandleOwner*>((reinterpret_cast<uintptr_t>(m_weakHandleOwner) & ~StateMask) | state);
91}
92
93inline const JSValue& WeakImpl::jsValue()
94{
95 return m_jsValue;
96}
97
98inline WeakHandleOwner* WeakImpl::weakHandleOwner()
99{
100 return reinterpret_cast<WeakHandleOwner*>((reinterpret_cast<uintptr_t>(m_weakHandleOwner) & ~StateMask));
101}
102
103inline void* WeakImpl::context()
104{
105 return m_context;
106}
107
108inline WeakImpl* WeakImpl::asWeakImpl(JSValue* slot)
109{
110 return reinterpret_cast_ptr<WeakImpl*>(reinterpret_cast_ptr<char*>(slot) + OBJECT_OFFSETOF(WeakImpl, m_jsValue));
111}
112
113} // namespace JSC
114
115#endif // WeakImpl_h
116