1/*
2 * Copyright (C) 2017, 2019 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#pragma once
27
28#include <wtf/Algorithms.h>
29#include <wtf/HashSet.h>
30#include <wtf/HashTraits.h>
31#include <wtf/WeakPtr.h>
32
33namespace WTF {
34
35template<> struct HashTraits<Ref<WeakPtrImpl>> : RefHashTraits<WeakPtrImpl> {
36 static const bool hasIsReleasedWeakValueFunction = true;
37 static bool isReleasedWeakValue(const Ref<WeakPtrImpl>& value)
38 {
39 return !value.isHashTableDeletedValue() && !value.isHashTableEmptyValue() && !value.get();
40 }
41};
42
43template <typename T>
44class WeakHashSet {
45public:
46 typedef HashSet<Ref<WeakPtrImpl>> WeakPtrImplSet;
47
48 class WeakHashSetConstIterator : public std::iterator<std::forward_iterator_tag, T, std::ptrdiff_t, const T*, const T&> {
49 private:
50 WeakHashSetConstIterator(const WeakPtrImplSet& set, typename WeakPtrImplSet::const_iterator position)
51 : m_position(position), m_endPosition(set.end())
52 {
53 skipEmptyBuckets();
54 }
55
56 public:
57 T* get() const { return static_cast<T*>((*m_position)->template get<T>()); }
58 T& operator*() const { return *get(); }
59 T* operator->() const { return get(); }
60
61 WeakHashSetConstIterator& operator++()
62 {
63 ASSERT(m_position != m_endPosition);
64 ++m_position;
65 skipEmptyBuckets();
66 return *this;
67 }
68
69 void skipEmptyBuckets()
70 {
71 while (m_position != m_endPosition && !get())
72 ++m_position;
73 }
74
75 bool operator==(const WeakHashSetConstIterator& other) const
76 {
77 return m_position == other.m_position;
78 }
79
80 bool operator!=(const WeakHashSetConstIterator& other) const
81 {
82 return m_position != other.m_position;
83 }
84
85 private:
86 template <typename> friend class WeakHashSet;
87
88 typename WeakPtrImplSet::const_iterator m_position;
89 typename WeakPtrImplSet::const_iterator m_endPosition;
90 };
91 typedef WeakHashSetConstIterator const_iterator;
92
93 WeakHashSet() { }
94
95 const_iterator begin() const { return WeakHashSetConstIterator(m_set, m_set.begin()); }
96 const_iterator end() const { return WeakHashSetConstIterator(m_set, m_set.end()); }
97
98 template <typename U>
99 void add(const U& value)
100 {
101 m_set.add(*makeWeakPtr<T>(const_cast<U&>(value)).m_impl);
102 }
103
104 template <typename U>
105 bool remove(const U& value)
106 {
107 auto& weakPtrImpl = value.weakPtrFactory().m_impl;
108 if (!weakPtrImpl || !*weakPtrImpl)
109 return false;
110 return m_set.remove(*weakPtrImpl);
111 }
112
113 template <typename U>
114 bool contains(const U& value) const
115 {
116 auto& weakPtrImpl = value.weakPtrFactory().m_impl;
117 if (!weakPtrImpl || !*weakPtrImpl)
118 return false;
119 return m_set.contains(*weakPtrImpl);
120 }
121
122 unsigned capacity() const { return m_set.capacity(); }
123
124 bool computesEmpty() const { return begin() == end(); }
125
126 bool hasNullReferences() const
127 {
128 return WTF::anyOf(m_set, [] (auto& value) { return !value.get(); });
129 }
130
131 unsigned computeSize() const
132 {
133 const_cast<WeakPtrImplSet&>(m_set).removeIf([] (auto& value) { return !value.get(); });
134 return m_set.size();
135 }
136
137#if ASSERT_DISABLED
138 void checkConsistency() const { }
139#else
140 void checkConsistency() const { m_set.checkConsistency(); }
141#endif
142
143private:
144 WeakPtrImplSet m_set;
145};
146
147} // namespace WTF
148
149using WTF::WeakHashSet;
150