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Diffstat (limited to 'gfx/layers/SourceSurfaceSharedData.h')
| -rw-r--r-- | gfx/layers/SourceSurfaceSharedData.h | 345 |
1 files changed, 345 insertions, 0 deletions
diff --git a/gfx/layers/SourceSurfaceSharedData.h b/gfx/layers/SourceSurfaceSharedData.h new file mode 100644 index 0000000000..73743a839d --- /dev/null +++ b/gfx/layers/SourceSurfaceSharedData.h @@ -0,0 +1,345 @@ +/* -*- 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_SOURCESURFACESHAREDDATA_H_ +#define MOZILLA_GFX_SOURCESURFACESHAREDDATA_H_ + +#include "mozilla/gfx/2D.h" +#include "mozilla/Mutex.h" +#include "mozilla/ipc/SharedMemoryBasic.h" +#include "nsExpirationTracker.h" + +namespace mozilla { +namespace gfx { + +class SourceSurfaceSharedData; + +/** + * This class is used to wrap shared (as in process) data buffers allocated by + * a SourceSurfaceSharedData object. It may live in the same process or a + * different process from the actual SourceSurfaceSharedData object. + * + * If it is in the same process, mBuf is the same object as that in the surface. + * It is a useful abstraction over just using the surface directly, because it + * can have a different lifetime from the surface; if the surface gets freed, + * consumers may continue accessing the data in the buffer. Releasing the + * original surface is a signal which feeds into SharedSurfacesParent to decide + * to release the SourceSurfaceSharedDataWrapper. + * + * If it is in a different process, mBuf is a new SharedMemoryBasic object which + * mapped in the given shared memory handle as read only memory. + */ +class SourceSurfaceSharedDataWrapper final : public DataSourceSurface { + typedef mozilla::ipc::SharedMemoryBasic SharedMemoryBasic; + + public: + MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(SourceSurfaceSharedDataWrapper, + override) + + SourceSurfaceSharedDataWrapper() + : mStride(0), + mConsumers(0), + mFormat(SurfaceFormat::UNKNOWN), + mCreatorPid(0), + mCreatorRef(true) {} + + void Init(const IntSize& aSize, int32_t aStride, SurfaceFormat aFormat, + SharedMemoryBasic::Handle aHandle, base::ProcessId aCreatorPid); + + void Init(SourceSurfaceSharedData* aSurface); + + base::ProcessId GetCreatorPid() const { return mCreatorPid; } + + int32_t Stride() override { return mStride; } + + SurfaceType GetType() const override { + return SurfaceType::DATA_SHARED_WRAPPER; + } + IntSize GetSize() const override { return mSize; } + SurfaceFormat GetFormat() const override { return mFormat; } + + uint8_t* GetData() override { return static_cast<uint8_t*>(mBuf->memory()); } + + bool OnHeap() const override { return false; } + + bool Map(MapType aMapType, MappedSurface* aMappedSurface) final; + + void Unmap() final; + + void ExpireMap(); + + bool AddConsumer() { return ++mConsumers == 1; } + + bool RemoveConsumer(bool aForCreator) { + MOZ_ASSERT(mConsumers > 0); + if (aForCreator) { + if (!mCreatorRef) { + MOZ_ASSERT_UNREACHABLE("Already released creator reference!"); + return false; + } + mCreatorRef = false; + } + return --mConsumers == 0; + } + + uint32_t GetConsumers() const { + MOZ_ASSERT(mConsumers > 0); + return mConsumers; + } + + bool HasCreatorRef() const { return mCreatorRef; } + + nsExpirationState* GetExpirationState() { return &mExpirationState; } + + private: + size_t GetDataLength() const { + return static_cast<size_t>(mStride) * mSize.height; + } + + size_t GetAlignedDataLength() const { + return mozilla::ipc::SharedMemory::PageAlignedSize(GetDataLength()); + } + + bool EnsureMapped(size_t aLength); + + // Protects mapping and unmapping of mBuf. + Maybe<Mutex> mHandleLock; + nsExpirationState mExpirationState; + int32_t mStride; + uint32_t mConsumers; + IntSize mSize; + RefPtr<SharedMemoryBasic> mBuf; + SurfaceFormat mFormat; + base::ProcessId mCreatorPid; + bool mCreatorRef; +}; + +/** + * This class is used to wrap shared (as in process) data buffers used by a + * source surface. + */ +class SourceSurfaceSharedData : public DataSourceSurface { + typedef mozilla::ipc::SharedMemoryBasic SharedMemoryBasic; + + public: + MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(SourceSurfaceSharedData, override) + + SourceSurfaceSharedData() + : mMutex("SourceSurfaceSharedData"), + mStride(0), + mHandleCount(0), + mFormat(SurfaceFormat::UNKNOWN), + mClosed(false), + mFinalized(false), + mShared(false) {} + + /** + * Initialize the surface by creating a shared memory buffer with a size + * determined by aSize, aStride and aFormat. If aShare is true, it will also + * immediately attempt to share the surface with the GPU process via + * SharedSurfacesChild. + */ + bool Init(const IntSize& aSize, int32_t aStride, SurfaceFormat aFormat, + bool aShare = true); + + uint8_t* GetData() final { + MutexAutoLock lock(mMutex); + return GetDataInternal(); + } + + int32_t Stride() final { return mStride; } + + SurfaceType GetType() const override { return SurfaceType::DATA_SHARED; } + IntSize GetSize() const final { return mSize; } + SurfaceFormat GetFormat() const final { return mFormat; } + + void SizeOfExcludingThis(MallocSizeOf aMallocSizeOf, + SizeOfInfo& aInfo) const final; + + bool OnHeap() const final { return false; } + + /** + * Although Map (and Moz2D in general) isn't normally threadsafe, + * we want to allow it for SourceSurfaceSharedData 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. + * + * Additionally if a reallocation happened while there were active + * mappings, then we guarantee that GetData will continue to return + * the same data pointer by retaining the old shared buffer until + * the last mapping is freed via Unmap. + */ + bool Map(MapType aMapType, MappedSurface* aMappedSurface) final { + MutexAutoLock lock(mMutex); + if (mFinalized && aMapType != MapType::READ) { + // Once finalized the data may be write-protected + return false; + } + ++mMapCount; + aMappedSurface->mData = GetDataInternal(); + aMappedSurface->mStride = mStride; + return true; + } + + void Unmap() final { + MutexAutoLock lock(mMutex); + MOZ_ASSERT(mMapCount > 0); + if (--mMapCount == 0) { + mOldBuf = nullptr; + } + } + + /** + * Get a handle to share to another process for this buffer. Returns: + * NS_OK -- success, aHandle is valid. + * NS_ERROR_NOT_AVAILABLE -- handle was closed, need to reallocate. + * NS_ERROR_FAILURE -- failed to create a handle to share. + */ + nsresult CloneHandle(SharedMemoryBasic::Handle& aHandle); + + /** + * Indicates the buffer is not expected to be shared with any more processes. + * May release the handle if possible (see CloseHandleInternal). + */ + void FinishedSharing() { + MutexAutoLock lock(mMutex); + mShared = true; + CloseHandleInternal(); + } + + /** + * Indicates whether or not the buffer can be shared with another process + * without reallocating. Note that this is racy and should only be used for + * informational/reporting purposes. + */ + bool CanShare() const { + MutexAutoLock lock(mMutex); + return !mClosed; + } + + /** + * Allocate a new shared memory buffer so that we can get a new handle for + * sharing to new processes. CloneHandle must have failed with + * NS_ERROR_NOT_AVAILABLE in order for this to be safe to call. Returns true + * if the operation succeeds. If it fails, there is no state change. + */ + bool ReallocHandle(); + + /** + * Signals we have finished writing to the buffer and it may be marked as + * read only. + */ + void Finalize(); + + /** + * Indicates whether or not the buffer can change. If this returns true, it is + * guaranteed to continue to do so for the remainder of the surface's life. + */ + bool IsFinalized() const { + MutexAutoLock lock(mMutex); + return mFinalized; + } + + /** + * Yields a dirty rect of what has changed since it was last called. + */ + Maybe<IntRect> TakeDirtyRect() final { + MutexAutoLock lock(mMutex); + if (mDirtyRect) { + Maybe<IntRect> ret = std::move(mDirtyRect); + return ret; + } + return Nothing(); + } + + /** + * Increment the invalidation counter. + */ + void Invalidate(const IntRect& aDirtyRect) final { + MutexAutoLock lock(mMutex); + if (!aDirtyRect.IsEmpty()) { + if (mDirtyRect) { + mDirtyRect->UnionRect(mDirtyRect.ref(), aDirtyRect); + } else { + mDirtyRect = Some(aDirtyRect); + } + } else { + mDirtyRect = Some(IntRect(IntPoint(0, 0), mSize)); + } + MOZ_ASSERT_IF(mDirtyRect, !mDirtyRect->IsEmpty()); + } + + /** + * While a HandleLock exists for the given surface, the shared memory handle + * cannot be released. + */ + class MOZ_STACK_CLASS HandleLock final { + public: + explicit HandleLock(SourceSurfaceSharedData* aSurface) + : mSurface(aSurface) { + mSurface->LockHandle(); + } + + ~HandleLock() { mSurface->UnlockHandle(); } + + private: + RefPtr<SourceSurfaceSharedData> mSurface; + }; + + protected: + virtual ~SourceSurfaceSharedData() = default; + + private: + friend class SourceSurfaceSharedDataWrapper; + + void LockHandle() { + MutexAutoLock lock(mMutex); + ++mHandleCount; + } + + void UnlockHandle() { + MutexAutoLock lock(mMutex); + MOZ_ASSERT(mHandleCount > 0); + --mHandleCount; + mShared = true; + CloseHandleInternal(); + } + + uint8_t* GetDataInternal() const; + + size_t GetDataLength() const { + return static_cast<size_t>(mStride) * mSize.height; + } + + size_t GetAlignedDataLength() const { + return mozilla::ipc::SharedMemory::PageAlignedSize(GetDataLength()); + } + + /** + * Attempt to close the handle. Only if the buffer has been both finalized + * and we have completed sharing will it be released. + */ + void CloseHandleInternal(); + + mutable Mutex mMutex MOZ_UNANNOTATED; + int32_t mStride; + int32_t mHandleCount; + Maybe<IntRect> mDirtyRect; + IntSize mSize; + RefPtr<SharedMemoryBasic> mBuf; + RefPtr<SharedMemoryBasic> mOldBuf; + SurfaceFormat mFormat; + bool mClosed : 1; + bool mFinalized : 1; + bool mShared : 1; +}; + +} // namespace gfx +} // namespace mozilla + +#endif /* MOZILLA_GFX_SOURCESURFACESHAREDDATA_H_ */ |