third_party/WebKit/Source/wtf/ArrayBufferContents.h

   1 /*
   2  * Copyright (C) 2009 Apple Inc. All rights reserved.
   3  * Copyright (C) 2013 Google Inc. All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  18  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  19  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  20  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  21  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  22  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #ifndef ArrayBufferContents_h
  28 #define ArrayBufferContents_h
  29
  30 #include "wtf/Assertions.h"
  31 #include "wtf/Noncopyable.h"
  32 #include "wtf/RefPtr.h"
  33 #include "wtf/ThreadSafeRefCounted.h"
  34 #include "wtf/WTF.h"
  35 #include "wtf/WTFExport.h"
  36
  37 namespace WTF {
  38
  39 class WTF_EXPORT ArrayBufferContents {
  40     WTF_MAKE_NONCOPYABLE(ArrayBufferContents);
  41 public:
  42     enum InitializationPolicy {
  43         ZeroInitialize,
  44         DontInitialize
  45     };
  46
  47     enum SharingType {
  48         NotShared,
  49         Shared,
  50     };
  51
  52     ArrayBufferContents();
  53     ArrayBufferContents(unsigned numElements, unsigned elementByteSize, SharingType isShared, ArrayBufferContents::InitializationPolicy);
  54
  55     // Use with care. data must be allocated with allocateMemory.
  56     // ArrayBufferContents will take ownership of the data and free it (using freeMemory)
  57     // upon destruction.
  58     // This constructor will not call observer->StartObserving(), so it is a responsibility
  59     // of the caller to make sure JS knows about external memory.
  60     ArrayBufferContents(void* data, unsigned sizeInBytes, SharingType isShared);
  61
  62     ~ArrayBufferContents();
  63
  64     void neuter();
  65
  66     void* data() const { return m_holder ? m_holder->data() : nullptr; }
  67     unsigned sizeInBytes() const { return m_holder ? m_holder->sizeInBytes() : 0; }
  68     bool isShared() const { return m_holder ? m_holder->isShared() : false; }
  69
  70     void transfer(ArrayBufferContents& other);
  71     void shareWith(ArrayBufferContents& other);
  72     void copyTo(ArrayBufferContents& other);
  73
  74     static void allocateMemory(size_t, InitializationPolicy, void*&);
  75     static void freeMemory(void*, size_t);
  76     static void setAdjustAmoutOfExternalAllocatedMemoryFunction(AdjustAmountOfExternalAllocatedMemoryFunction function)
  77     {
  78         ASSERT(!s_adjustAmountOfExternalAllocatedMemoryFunction);
  79         s_adjustAmountOfExternalAllocatedMemoryFunction = function;
  80     }
  81
  82 private:
  83     class DataHolder : public ThreadSafeRefCounted<DataHolder> {
  84         WTF_MAKE_NONCOPYABLE(DataHolder);
  85     public:
  86         DataHolder();
  87         ~DataHolder();
  88
  89         void allocateNew(unsigned sizeInBytes, SharingType isShared, InitializationPolicy);
  90         void adopt(void* data, unsigned sizeInBytes, SharingType isShared);
  91         void copyMemoryTo(DataHolder& other);
  92
  93         void* data() const { return m_data; }
  94         unsigned sizeInBytes() const { return m_sizeInBytes; }
  95         bool isShared() const { return m_isShared == Shared; }
  96
  97     private:
  98         void* m_data;
  99         unsigned m_sizeInBytes;
 100         SharingType m_isShared;
 101     };
 102
 103     RefPtr<DataHolder> m_holder;
 104     static AdjustAmountOfExternalAllocatedMemoryFunction s_adjustAmountOfExternalAllocatedMemoryFunction;
 105 };
 106
 107 } // namespace WTF
 108
 109 #endif // ArrayBufferContents_h