JavaScriptCore-1097.13.tar.gz
[apple/javascriptcore.git] / heap / WeakSet.cpp
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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#include "config.h"
27#include "WeakSet.h"
28
29#include "Heap.h"
30
31namespace JSC {
32
33WeakSet::~WeakSet()
34{
35 WeakBlock* next = 0;
36 for (WeakBlock* block = m_blocks.head(); block; block = next) {
37 next = block->next();
38 WeakBlock::destroy(block);
39 }
40 m_blocks.clear();
41}
42
43void WeakSet::finalizeAll()
44{
45 for (WeakBlock* block = m_blocks.head(); block; block = block->next())
46 block->finalizeAll();
47}
48
49void WeakSet::visitLiveWeakImpls(HeapRootVisitor& visitor)
50{
51 for (WeakBlock* block = m_blocks.head(); block; block = block->next())
52 block->visitLiveWeakImpls(visitor);
53}
54
55void WeakSet::visitDeadWeakImpls(HeapRootVisitor& visitor)
56{
57 for (WeakBlock* block = m_blocks.head(); block; block = block->next())
58 block->visitDeadWeakImpls(visitor);
59}
60
61void WeakSet::sweep()
62{
63 WeakBlock* next;
64 for (WeakBlock* block = m_blocks.head(); block; block = next) {
65 next = block->next();
66
67 // If a block is completely empty, a new sweep won't have any effect.
68 if (!block->sweepResult().isNull() && block->sweepResult().blockIsFree)
69 continue;
70
71 block->takeSweepResult(); // Force a new sweep by discarding the last sweep.
72 block->sweep();
73 }
74}
75
76void WeakSet::shrink()
77{
78 WeakBlock* next;
79 for (WeakBlock* block = m_blocks.head(); block; block = next) {
80 next = block->next();
81
82 if (!block->sweepResult().isNull() && block->sweepResult().blockIsFree)
83 removeAllocator(block);
84 }
85}
86
87void WeakSet::resetAllocator()
88{
89 m_allocator = 0;
90 m_nextAllocator = m_blocks.head();
91}
92
93WeakBlock::FreeCell* WeakSet::findAllocator()
94{
95 if (WeakBlock::FreeCell* allocator = tryFindAllocator())
96 return allocator;
97
98 return addAllocator();
99}
100
101WeakBlock::FreeCell* WeakSet::tryFindAllocator()
102{
103 while (m_nextAllocator) {
104 WeakBlock* block = m_nextAllocator;
105 m_nextAllocator = m_nextAllocator->next();
106
107 block->sweep();
108 WeakBlock::SweepResult sweepResult = block->takeSweepResult();
109 if (sweepResult.freeList)
110 return sweepResult.freeList;
111 }
112
113 return 0;
114}
115
116WeakBlock::FreeCell* WeakSet::addAllocator()
117{
118 WeakBlock* block = WeakBlock::create();
119 m_heap->didAllocate(WeakBlock::blockSize);
120 m_blocks.append(block);
121 WeakBlock::SweepResult sweepResult = block->takeSweepResult();
122 ASSERT(!sweepResult.isNull() && sweepResult.freeList);
123 return sweepResult.freeList;
124}
125
126void WeakSet::removeAllocator(WeakBlock* block)
127{
128 m_blocks.remove(block);
129 WeakBlock::destroy(block);
130}
131
132} // namespace JSC