1/*
2 * Copyright (C) 2009 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. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef ConservativeRoots_h
27#define ConservativeRoots_h
28
29#include "Heap.h"
30#include <wtf/OSAllocator.h>
31#include <wtf/Vector.h>
32
33namespace JSC {
34
35class JSCell;
36class Heap;
37
38// May contain duplicates.
39
40class ConservativeRoots {
41public:
42    ConservativeRoots(Heap*);
43    ~ConservativeRoots();
44
45    void add(void*);
46    void add(void* begin, void* end);
47
48    size_t size();
49    JSCell** roots();
50
51private:
52    static const size_t inlineCapacity = 128;
53    static const size_t nonInlineCapacity = 8192 / sizeof(JSCell*);
54
55    void grow();
56
57    Heap* m_heap;
58    JSCell** m_roots;
59    size_t m_size;
60    size_t m_capacity;
61    JSCell* m_inlineRoots[inlineCapacity];
62};
63
64inline ConservativeRoots::ConservativeRoots(Heap* heap)
65    : m_heap(heap)
66    , m_roots(m_inlineRoots)
67    , m_size(0)
68    , m_capacity(inlineCapacity)
69{
70}
71
72inline ConservativeRoots::~ConservativeRoots()
73{
74    if (m_roots != m_inlineRoots)
75        OSAllocator::decommitAndRelease(m_roots, m_capacity * sizeof(JSCell*));
76}
77
78inline void ConservativeRoots::add(void* p)
79{
80    if (!m_heap->contains(p))
81        return;
82
83    if (m_size == m_capacity)
84        grow();
85
86    m_roots[m_size++] = reinterpret_cast<JSCell*>(p);
87}
88
89inline size_t ConservativeRoots::size()
90{
91    return m_size;
92}
93
94inline JSCell** ConservativeRoots::roots()
95{
96    return m_roots;
97}
98
99} // namespace JSC
100
101#endif // ConservativeRoots_h
102