heap/MarkedBlockSet.h

   1 /*
   2  * Copyright (C) 2011 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 MarkedBlockSet_h
  27 #define MarkedBlockSet_h
  28
  29 #include "MarkedBlock.h"
  30 #include "TinyBloomFilter.h"
  31 #include <wtf/HashSet.h>
  32
  33 namespace JSC {
  34
  35 class MarkedBlock;
  36
  37 class MarkedBlockSet {
  38 public:
  39     void add(MarkedBlock*);
  40     void remove(MarkedBlock*);
  41
  42     TinyBloomFilter filter() const;
  43     const HashSet<MarkedBlock*>& set() const;
  44
  45 private:
  46     void recomputeFilter();
  47
  48     TinyBloomFilter m_filter;
  49     HashSet<MarkedBlock*> m_set;
  50 };
  51
  52 inline void MarkedBlockSet::add(MarkedBlock* block)
  53 {
  54     m_filter.add(reinterpret_cast<Bits>(block));
  55     m_set.add(block);
  56 }
  57
  58 inline void MarkedBlockSet::remove(MarkedBlock* block)
  59 {
  60     int oldCapacity = m_set.capacity();
  61     m_set.remove(block);
  62     if (m_set.capacity() != oldCapacity) // Indicates we've removed a lot of blocks.
  63         recomputeFilter();
  64 }
  65
  66 inline void MarkedBlockSet::recomputeFilter()
  67 {
  68     TinyBloomFilter filter;
  69     for (HashSet<MarkedBlock*>::iterator it = m_set.begin(); it != m_set.end(); ++it)
  70         filter.add(reinterpret_cast<Bits>(*it));
  71     m_filter = filter;
  72 }
  73
  74 inline TinyBloomFilter MarkedBlockSet::filter() const
  75 {
  76     return m_filter;
  77 }
  78
  79 inline const HashSet<MarkedBlock*>& MarkedBlockSet::set() const
  80 {
  81     return m_set;
  82 }
  83
  84 } // namespace JSC
  85
  86 #endif // MarkedBlockSet_h