heap/DeferGC.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. ``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 DeferGC_h
  27 #define DeferGC_h
  28
  29 #include "Heap.h"
  30 #include <wtf/Noncopyable.h>
  31 #include <wtf/ThreadSpecific.h>
  32
  33 namespace JSC {
  34
  35 class DeferGC {
  36     WTF_MAKE_NONCOPYABLE(DeferGC);
  37 public:
  38     DeferGC(Heap& heap)
  39         : m_heap(heap)
  40     {
  41         m_heap.incrementDeferralDepth();
  42     }
  43
  44     ~DeferGC()
  45     {
  46         m_heap.decrementDeferralDepthAndGCIfNeeded();
  47     }
  48
  49 private:
  50     Heap& m_heap;
  51 };
  52
  53 class DeferGCForAWhile {
  54     WTF_MAKE_NONCOPYABLE(DeferGCForAWhile);
  55 public:
  56     DeferGCForAWhile(Heap& heap)
  57         : m_heap(heap)
  58     {
  59         m_heap.incrementDeferralDepth();
  60     }
  61
  62     ~DeferGCForAWhile()
  63     {
  64         m_heap.decrementDeferralDepth();
  65     }
  66
  67 private:
  68     Heap& m_heap;
  69 };
  70
  71 #ifndef NDEBUG
  72 class DisallowGC {
  73     WTF_MAKE_NONCOPYABLE(DisallowGC);
  74 public:
  75     DisallowGC()
  76     {
  77         WTF::threadSpecificSet(s_isGCDisallowedOnCurrentThread, reinterpret_cast<void*>(true));
  78     }
  79
  80     ~DisallowGC()
  81     {
  82         WTF::threadSpecificSet(s_isGCDisallowedOnCurrentThread, reinterpret_cast<void*>(false));
  83     }
  84
  85     static bool isGCDisallowedOnCurrentThread()
  86     {
  87         return !!WTF::threadSpecificGet(s_isGCDisallowedOnCurrentThread);
  88     }
  89     static void initialize()
  90     {
  91         WTF::threadSpecificKeyCreate(&s_isGCDisallowedOnCurrentThread, 0);
  92     }
  93
  94     JS_EXPORT_PRIVATE static WTF::ThreadSpecificKey s_isGCDisallowedOnCurrentThread;
  95 };
  96 #endif // NDEBUG
  97
  98 } // namespace JSC
  99
 100 #endif // DeferGC_h
 101