1/*
2 * Copyright (C) 2009, 2012, 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 WeakInlines_h
27#define WeakInlines_h
28
29#include "JSCell.h"
30#include "WeakSetInlines.h"
31#include <wtf/Assertions.h>
32#include <wtf/HashTraits.h>
33
34namespace JSC {
35
36template<typename T> inline Weak<T>::Weak(T* cell, WeakHandleOwner* weakOwner, void* context)
37 : m_impl(cell ? WeakSet::allocate(cell, weakOwner, context) : 0)
38{
39}
40
41template<typename T> inline bool Weak<T>::isHashTableDeletedValue() const
42{
43 return m_impl == hashTableDeletedValue();
44}
45
46template<typename T> inline Weak<T>::Weak(typename Weak<T>::HashTableDeletedValueTag)
47 : m_impl(hashTableDeletedValue())
48{
49}
50
51template<typename T> inline Weak<T>::Weak(Weak&& other)
52 : m_impl(other.leakImpl())
53{
54}
55
56template<class T> inline void swap(Weak<T>& a, Weak<T>& b)
57{
58 a.swap(b);
59}
60
61template<typename T> inline void Weak<T>::swap(Weak& other)
62{
63 std::swap(m_impl, other.m_impl);
64}
65
66template<typename T> inline auto Weak<T>::operator=(Weak&& other) -> Weak&
67{
68 Weak weak = WTFMove(other);
69 swap(weak);
70 return *this;
71}
72
73template<typename T> inline T* Weak<T>::operator->() const
74{
75 ASSERT(m_impl && m_impl->state() == WeakImpl::Live);
76 return jsCast<T*>(m_impl->jsValue().asCell());
77}
78
79template<typename T> inline T& Weak<T>::operator*() const
80{
81 ASSERT(m_impl && m_impl->state() == WeakImpl::Live);
82 return *jsCast<T*>(m_impl->jsValue().asCell());
83}
84
85template<typename T> inline T* Weak<T>::get() const
86{
87 if (!m_impl || m_impl->state() != WeakImpl::Live)
88 return 0;
89 return jsCast<T*>(m_impl->jsValue().asCell());
90}
91
92template<typename T> inline bool Weak<T>::was(T* other) const
93{
94 return static_cast<T*>(m_impl->jsValue().asCell()) == other;
95}
96
97template<typename T> inline bool Weak<T>::operator!() const
98{
99 return !m_impl || !m_impl->jsValue() || m_impl->state() != WeakImpl::Live;
100}
101
102template<typename T> inline Weak<T>::operator bool() const
103{
104 return !!*this;
105}
106
107template<typename T> inline WeakImpl* Weak<T>::leakImpl()
108{
109 WeakImpl* impl = m_impl;
110 m_impl = nullptr;
111 return impl;
112}
113
114template<typename T> inline WeakImpl* Weak<T>::hashTableDeletedValue()
115{
116 return reinterpret_cast<WeakImpl*>(-1);
117}
118
119template <typename T> inline bool operator==(const Weak<T>& lhs, const Weak<T>& rhs)
120{
121 return lhs.get() == rhs.get();
122}
123
124// This function helps avoid modifying a weak table while holding an iterator into it. (Object allocation
125// can run a finalizer that modifies the table. We avoid that by requiring a pre-constructed object as our value.)
126template<typename Map, typename Key, typename Value> inline void weakAdd(Map& map, const Key& key, Value&& value)
127{
128 ASSERT(!map.get(key));
129 map.set(key, std::forward<Value>(value)); // The table may still have a zombie for value.
130}
131
132template<typename Map, typename Key, typename Value> inline void weakRemove(Map& map, const Key& key, Value value)
133{
134 typename Map::iterator it = map.find(key);
135 ASSERT_UNUSED(value, value);
136 ASSERT(it != map.end());
137 ASSERT(it->value.was(value));
138 ASSERT(!it->value);
139 map.remove(it);
140}
141
142template<typename T> inline void weakClear(Weak<T>& weak, T* cell)
143{
144 ASSERT_UNUSED(cell, cell);
145 ASSERT(weak.was(cell));
146 ASSERT(!weak);
147 weak.clear();
148}
149
150} // namespace JSC
151
152namespace WTF {
153
154template<typename T> struct VectorTraits<JSC::Weak<T>> : SimpleClassVectorTraits {
155 static const bool canCompareWithMemcmp = false;
156};
157
158template<typename T> struct HashTraits<JSC::Weak<T>> : SimpleClassHashTraits<JSC::Weak<T>> {
159 typedef JSC::Weak<T> StorageType;
160
161 typedef std::nullptr_t EmptyValueType;
162 static EmptyValueType emptyValue() { return nullptr; }
163
164 typedef T* PeekType;
165 static PeekType peek(const StorageType& value) { return value.get(); }
166 static PeekType peek(EmptyValueType) { return PeekType(); }
167};
168
169} // namespace WTF
170
171#endif // WeakInlines_h
172