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