heap/HandleBlock.h

   1 /*
   2  * Copyright (C) 2013 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 HandleBlock_h
  27 #define HandleBlock_h
  28
  29 #include "HeapBlock.h"
  30
  31 namespace JSC {
  32
  33 class DeadBlock;
  34 class HandleSet;
  35 class HandleNode;
  36
  37 class HandleBlock : public HeapBlock<HandleBlock> {
  38 public:
  39     static HandleBlock* create(DeadBlock*, HandleSet*);
  40     static HandleBlock* blockFor(HandleNode*);
  41
  42     static const size_t blockSize = 4 * KB;
  43
  44     HandleSet* handleSet();
  45
  46     HandleNode* nodes();
  47     HandleNode* nodeAtIndex(unsigned);
  48     unsigned nodeCapacity();
  49
  50 private:
  51     HandleBlock(Region*, HandleSet*);
  52
  53     char* payload();
  54     char* payloadEnd();
  55
  56     static const size_t s_blockMask = ~(blockSize - 1);
  57
  58     HandleSet* m_handleSet;
  59 };
  60
  61 inline HandleBlock* HandleBlock::blockFor(HandleNode* node)
  62 {
  63     return reinterpret_cast<HandleBlock*>(reinterpret_cast<size_t>(node) & s_blockMask);
  64 }
  65
  66 inline HandleSet* HandleBlock::handleSet()
  67 {
  68     return m_handleSet;
  69 }
  70
  71 } // namespace JSC
  72
  73 #endif // HandleBlock_h