/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "VolatileBuffer.h"

#include "mozilla/Assertions.h"

#include "mozilla/mozalloc.h"

#ifdef MOZ_MEMORY

int posix_memalign(void** memptr, size_t alignment, size_t size);

#endif

namespace mozilla {

VolatileBuffer::VolatileBuffer()

  : mMutex("VolatileBuffer")

  , mBuf(nullptr)

  , mSize(0)

  , mLockCount(0)

{

}

bool VolatileBuffer::Init(size_t aSize, size_t aAlignment)

{

  MOZ_ASSERT(!mSize && !mBuf, "Init called twice");

  MOZ_ASSERT(!(aAlignment % sizeof(void *)),

             "Alignment must be multiple of pointer size");

  mSize = aSize;

#if defined(MOZ_MEMORY) || defined(HAVE_POSIX_MEMALIGN)

  if (posix_memalign(&mBuf, aAlignment, aSize) != 0) {

    return false;

  }

#else

#error "No memalign implementation found"

#endif

  return !!mBuf;

}

VolatileBuffer::~VolatileBuffer()

{

  MOZ_ASSERT(mLockCount == 0, "Being destroyed with non-zero lock count?");

  free(mBuf);

}

bool

VolatileBuffer::Lock(void** aBuf)

{

  MutexAutoLock lock(mMutex);

  MOZ_ASSERT(mBuf, "Attempting to lock an uninitialized VolatileBuffer");

  *aBuf = mBuf;

  mLockCount++;

  return true;

}

void

VolatileBuffer::Unlock()

{

  MutexAutoLock lock(mMutex);

  mLockCount--;

  MOZ_ASSERT(mLockCount >= 0, "VolatileBuffer unlocked too many times!");

}

bool

VolatileBuffer::OnHeap() const

{

  return true;

}

size_t

VolatileBuffer::HeapSizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const

{

  return aMallocSizeOf(mBuf);

}

size_t

VolatileBuffer::NonHeapSizeOfExcludingThis() const

{

  return 0;

}

} // namespace mozilla