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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/. */
#ifndef MOZILLA_GFX_SOURCESURFACEVOLATILEDATA_H_
#define MOZILLA_GFX_SOURCESURFACEVOLATILEDATA_H_
#include "mozilla/gfx/2D.h"
#include "mozilla/Mutex.h"
#include "mozilla/VolatileBuffer.h"
namespace mozilla {
namespace gfx {
/**
* This class is used to wrap volatile data buffers used for source surfaces.
* The Map and Unmap semantics are used to guarantee that the volatile data
* buffer is not freed by the operating system while the surface is in active
* use. If GetData is expected to return a non-null value without a
* corresponding Map call (and verification of the result), the surface data
* should be wrapped in a temporary SourceSurfaceRawData with a ScopedMap
* closure.
*/
class SourceSurfaceVolatileData : public DataSourceSurface {
public:
MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(SourceSurfaceVolatileData, override)
SourceSurfaceVolatileData()
: mMutex("SourceSurfaceVolatileData"),
mStride(0),
mFormat(SurfaceFormat::UNKNOWN),
mWasPurged(false) {}
bool Init(const IntSize& aSize, int32_t aStride, SurfaceFormat aFormat);
uint8_t* GetData() override { return mVBufPtr; }
int32_t Stride() override { return mStride; }
SurfaceType GetType() const override { return SurfaceType::DATA; }
IntSize GetSize() const override { return mSize; }
SurfaceFormat GetFormat() const override { return mFormat; }
void GuaranteePersistance() override;
void SizeOfExcludingThis(MallocSizeOf aMallocSizeOf,
SizeOfInfo& aInfo) const override;
bool OnHeap() const override { return mVBuf->OnHeap(); }
// Althought Map (and Moz2D in general) isn't normally threadsafe,
// we want to allow it for SourceSurfaceVolatileData since it should
// always be fine (for reading at least).
//
// This is the same as the base class implementation except using
// mMapCount instead of mIsMapped since that breaks for multithread.
bool Map(MapType, MappedSurface* aMappedSurface) override {
MutexAutoLock lock(mMutex);
if (mWasPurged) {
return false;
}
if (mMapCount == 0) {
mVBufPtr = mVBuf;
}
if (mVBufPtr.WasBufferPurged()) {
mWasPurged = true;
return false;
}
aMappedSurface->mData = mVBufPtr;
aMappedSurface->mStride = mStride;
++mMapCount;
return true;
}
void Unmap() override {
MutexAutoLock lock(mMutex);
MOZ_ASSERT(mMapCount > 0);
MOZ_ASSERT(!mWasPurged);
if (--mMapCount == 0) {
mVBufPtr = nullptr;
}
}
private:
virtual ~SourceSurfaceVolatileData() = default;
Mutex mMutex;
int32_t mStride;
IntSize mSize;
RefPtr<VolatileBuffer> mVBuf;
VolatileBufferPtr<uint8_t> mVBufPtr;
SurfaceFormat mFormat;
bool mWasPurged;
};
} // namespace gfx
} // namespace mozilla
#endif /* MOZILLA_GFX_SOURCESURFACEVOLATILEDATA_H_ */
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