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 WeakSet_h
27#define WeakSet_h
28
29#include "WeakBlock.h"
30
31namespace JSC {
32
33class Heap;
34class WeakImpl;
35
36class WeakSet {
37    friend class LLIntOffsetsExtractor;
38
39public:
40    static WeakImpl* allocate(JSValue, WeakHandleOwner* = 0, void* context = 0);
41    static void deallocate(WeakImpl*);
42
43    WeakSet(VM*);
44    ~WeakSet();
45    void lastChanceToFinalize();
46
47    Heap* heap() const;
48    VM* vm() const;
49
50    bool isEmpty() const;
51
52    void visit(HeapRootVisitor&);
53    void reap();
54    void sweep();
55    void shrink();
56    void resetAllocator();
57
58private:
59    JS_EXPORT_PRIVATE WeakBlock::FreeCell* findAllocator();
60    WeakBlock::FreeCell* tryFindAllocator();
61    WeakBlock::FreeCell* addAllocator();
62    void removeAllocator(WeakBlock*);
63
64    WeakBlock::FreeCell* m_allocator;
65    WeakBlock* m_nextAllocator;
66    DoublyLinkedList<WeakBlock> m_blocks;
67    VM* m_vm;
68};
69
70inline WeakSet::WeakSet(VM* vm)
71    : m_allocator(0)
72    , m_nextAllocator(0)
73    , m_vm(vm)
74{
75}
76
77inline VM* WeakSet::vm() const
78{
79    return m_vm;
80}
81
82inline bool WeakSet::isEmpty() const
83{
84    for (WeakBlock* block = m_blocks.head(); block; block = block->next()) {
85        if (!block->isEmpty())
86            return false;
87    }
88
89    return true;
90}
91
92inline void WeakSet::deallocate(WeakImpl* weakImpl)
93{
94    weakImpl->setState(WeakImpl::Deallocated);
95}
96
97inline void WeakSet::lastChanceToFinalize()
98{
99    for (WeakBlock* block = m_blocks.head(); block; block = block->next())
100        block->lastChanceToFinalize();
101}
102
103inline void WeakSet::visit(HeapRootVisitor& visitor)
104{
105    for (WeakBlock* block = m_blocks.head(); block; block = block->next())
106        block->visit(visitor);
107}
108
109inline void WeakSet::reap()
110{
111    for (WeakBlock* block = m_blocks.head(); block; block = block->next())
112        block->reap();
113}
114
115inline void WeakSet::shrink()
116{
117    WeakBlock* next;
118    for (WeakBlock* block = m_blocks.head(); block; block = next) {
119        next = block->next();
120
121        if (block->isEmpty())
122            removeAllocator(block);
123    }
124
125    resetAllocator();
126}
127
128inline void WeakSet::resetAllocator()
129{
130    m_allocator = 0;
131    m_nextAllocator = m_blocks.head();
132}
133
134} // namespace JSC
135
136#endif // WeakSet_h
137