memory/mozalloc/VolatileBufferFallback.cpp

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include "VolatileBuffer.h"
   6 #include "mozilla/Assertions.h"
   7 #include "mozilla/NullPtr.h"
   8 #include "mozilla/mozalloc.h"
   9
  10 #ifdef MOZ_MEMORY
  11 int posix_memalign(void** memptr, size_t alignment, size_t size);
  12 #endif
  13
  14 namespace mozilla {
  15
  16 VolatileBuffer::VolatileBuffer()
  17   : mBuf(nullptr)
  18   , mSize(0)
  19   , mLockCount(0)
  20 {
  21 }
  22
  23 bool VolatileBuffer::Init(size_t aSize, size_t aAlignment)
  24 {
  25   MOZ_ASSERT(!mSize && !mBuf, "Init called twice");
  26   MOZ_ASSERT(!(aAlignment % sizeof(void *)),
  27              "Alignment must be multiple of pointer size");
  28
  29   mSize = aSize;
  30 #if defined(MOZ_MEMORY)
  31   posix_memalign(&mBuf, aAlignment, aSize);
  32 #elif defined(HAVE_POSIX_MEMALIGN)
  33   (void)moz_posix_memalign(&mBuf, aAlignment, aSize);
  34 #else
  35 #error "No memalign implementation found"
  36 #endif
  37   return !!mBuf;
  38 }
  39
  40 VolatileBuffer::~VolatileBuffer()
  41 {
  42   free(mBuf);
  43 }
  44
  45 bool
  46 VolatileBuffer::Lock(void** aBuf)
  47 {
  48   MOZ_ASSERT(mBuf, "Attempting to lock an uninitialized VolatileBuffer");
  49
  50   *aBuf = mBuf;
  51   mLockCount++;
  52
  53   return true;
  54 }
  55
  56 void
  57 VolatileBuffer::Unlock()
  58 {
  59   mLockCount--;
  60   MOZ_ASSERT(mLockCount >= 0, "VolatileBuffer unlocked too many times!");
  61 }
  62
  63 bool
  64 VolatileBuffer::OnHeap() const
  65 {
  66   return true;
  67 }
  68
  69 size_t
  70 VolatileBuffer::HeapSizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
  71 {
  72   return aMallocSizeOf(mBuf);
  73 }
  74
  75 size_t
  76 VolatileBuffer::NonHeapSizeOfExcludingThis() const
  77 {
  78   return 0;
  79 }
  80
  81 } // namespace mozilla