heap/CopyWorkList.h

   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 CopyWorkList_h
  27 #define CopyWorkList_h
  28
  29 #include <wtf/Vector.h>
  30
  31 namespace JSC {
  32
  33 class JSCell;
  34
  35 class CopyWorkListSegment : public HeapBlock<CopyWorkListSegment> {
  36 public:
  37     static CopyWorkListSegment* create(DeadBlock* block)
  38     {
  39         return new (NotNull, block) CopyWorkListSegment(block->region());
  40     }
  41
  42     size_t size() { return m_size; }
  43     bool isFull() { return reinterpret_cast<char*>(&data()[size()]) >= endOfBlock(); }
  44     JSCell* get(size_t index) { return data()[index]; }
  45
  46     void append(JSCell* cell)
  47     {
  48         ASSERT(!isFull());
  49         data()[m_size] = cell;
  50         m_size += 1;
  51     }
  52
  53     static const size_t blockSize = 512;
  54
  55 private:
  56     CopyWorkListSegment(Region* region)
  57         : HeapBlock<CopyWorkListSegment>(region)
  58         , m_size(0)
  59     {
  60     }
  61
  62     JSCell** data() { return reinterpret_cast<JSCell**>(this + 1); }
  63     char* endOfBlock() { return reinterpret_cast<char*>(this) + blockSize; }
  64
  65     size_t m_size;
  66 };
  67
  68 class CopyWorkListIterator {
  69     friend class CopyWorkList;
  70 public:
  71     JSCell* get() { return m_currentSegment->get(m_currentIndex); }
  72     JSCell* operator*() { return get(); }
  73     JSCell* operator->() { return get(); }
  74
  75     CopyWorkListIterator& operator++()
  76     {
  77         m_currentIndex++;
  78
  79         if (m_currentIndex >= m_currentSegment->size()) {
  80             m_currentIndex = 0;
  81             m_currentSegment = m_currentSegment->next();
  82
  83             ASSERT(!m_currentSegment || m_currentSegment->size());
  84         }
  85
  86         return *this;
  87     }
  88
  89     bool operator==(const CopyWorkListIterator& other) const
  90     {
  91         return m_currentSegment == other.m_currentSegment && m_currentIndex == other.m_currentIndex;
  92     }
  93
  94     bool operator!=(const CopyWorkListIterator& other) const
  95     {
  96         return !(*this == other);
  97     }
  98
  99     CopyWorkListIterator()
 100         : m_currentSegment(0)
 101         , m_currentIndex(0)
 102     {
 103     }
 104
 105 private:
 106     CopyWorkListIterator(CopyWorkListSegment* startSegment, size_t startIndex)
 107         : m_currentSegment(startSegment)
 108         , m_currentIndex(startIndex)
 109     {
 110     }
 111
 112     CopyWorkListSegment* m_currentSegment;
 113     size_t m_currentIndex;
 114 };
 115
 116 class CopyWorkList {
 117 public:
 118     typedef CopyWorkListIterator iterator;
 119
 120     CopyWorkList(BlockAllocator&);
 121     ~CopyWorkList();
 122
 123     void append(JSCell*);
 124     iterator begin();
 125     iterator end();
 126
 127 private:
 128     DoublyLinkedList<CopyWorkListSegment> m_segments;
 129     BlockAllocator& m_blockAllocator;
 130 };
 131
 132 inline CopyWorkList::CopyWorkList(BlockAllocator& blockAllocator)
 133     : m_blockAllocator(blockAllocator)
 134 {
 135 }
 136
 137 inline CopyWorkList::~CopyWorkList()
 138 {
 139     while (!m_segments.isEmpty())
 140         m_blockAllocator.deallocate(CopyWorkListSegment::destroy(m_segments.removeHead()));
 141 }
 142
 143 inline void CopyWorkList::append(JSCell* cell)
 144 {
 145     if (m_segments.isEmpty() || m_segments.tail()->isFull())
 146         m_segments.append(CopyWorkListSegment::create(m_blockAllocator.allocate<CopyWorkListSegment>()));
 147
 148     ASSERT(!m_segments.tail()->isFull());
 149
 150     m_segments.tail()->append(cell);
 151 }
 152
 153 inline CopyWorkList::iterator CopyWorkList::begin()
 154 {
 155     return CopyWorkListIterator(m_segments.head(), 0);
 156 }
 157
 158 inline CopyWorkList::iterator CopyWorkList::end()
 159 {
 160     return CopyWorkListIterator();
 161 }
 162
 163 } // namespace JSC
 164
 165 #endif // CopyWorkList_h