/* 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
