1/*
2 * Copyright (C) 2009, 2015-2016 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 "Weak.h"
29#include <wtf/HashMap.h>
30
31namespace JSC {
32
33// A HashMap with Weak<JSCell> values, which automatically removes values once they're garbage collected.
34
35class WeakGCMapBase {
36public:
37 virtual ~WeakGCMapBase() { }
38 virtual void pruneStaleEntries() = 0;
39};
40
41template<typename KeyArg, typename ValueArg, typename HashArg = typename DefaultHash<KeyArg>::Hash,
42 typename KeyTraitsArg = HashTraits<KeyArg>>
43class WeakGCMap : public WeakGCMapBase {
44 WTF_MAKE_FAST_ALLOCATED;
45 typedef Weak<ValueArg> ValueType;
46 typedef HashMap<KeyArg, ValueType, HashArg, KeyTraitsArg> HashMapType;
47
48public:
49 typedef typename HashMapType::KeyType KeyType;
50 typedef typename HashMapType::AddResult AddResult;
51 typedef typename HashMapType::iterator iterator;
52 typedef typename HashMapType::const_iterator const_iterator;
53
54 explicit WeakGCMap(VM&);
55 ~WeakGCMap();
56
57 ValueArg* get(const KeyType& key) const
58 {
59 return m_map.get(key);
60 }
61
62 AddResult set(const KeyType& key, ValueType value)
63 {
64 return m_map.set(key, WTFMove(value));
65 }
66
67 bool remove(const KeyType& key)
68 {
69 return m_map.remove(key);
70 }
71
72 void clear()
73 {
74 m_map.clear();
75 }
76
77 bool isEmpty() const
78 {
79 const_iterator it = m_map.begin();
80 const_iterator end = m_map.end();
81 while (it != end) {
82 if (it->value)
83 return true;
84 }
85 return false;
86 }
87
88 inline iterator find(const KeyType& key);
89
90 inline const_iterator find(const KeyType& key) const;
91
92 inline bool contains(const KeyType& key) const;
93
94 void pruneStaleEntries() override;
95
96private:
97 HashMapType m_map;
98 VM& m_vm;
99};
100
101} // namespace JSC
102