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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_layers_CanvasDrawEventRecorder_h
#define mozilla_layers_CanvasDrawEventRecorder_h
#include <queue>
#include "mozilla/Atomics.h"
#include "mozilla/gfx/DrawEventRecorder.h"
#include "mozilla/ipc/CrossProcessSemaphore.h"
#include "mozilla/ipc/SharedMemoryBasic.h"
#include "mozilla/layers/LayersTypes.h"
#include "mozilla/RefPtr.h"
#include "mozilla/UniquePtr.h"
namespace mozilla {
using EventType = gfx::RecordedEvent::EventType;
namespace layers {
typedef mozilla::ipc::SharedMemoryBasic::Handle Handle;
typedef mozilla::CrossProcessSemaphoreHandle CrossProcessSemaphoreHandle;
class CanvasDrawEventRecorder final : public gfx::DrawEventRecorderPrivate,
public gfx::ContiguousBufferStream {
public:
MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(CanvasDrawEventRecorder, final)
CanvasDrawEventRecorder();
enum class State : uint32_t {
Processing,
/**
* This is the important state to make sure the other side signals or starts
* us as soon as data or space is available. We set AboutToWait first and
* then re-check the condition. If we went straight to Waiting or Stopped
* then in between the last check and setting the state, the other side
* could have used all available data or space and never have signaled us
* because it didn't know we were about to wait, causing a deadlock.
* While we are in this state, the other side must wait until we resolve the
* AboutToWait state to one of the other states and then signal or start us
* if it needs to.
*/
AboutToWait,
Waiting,
Paused,
Stopped,
Failed,
};
struct Header {
Atomic<int64_t> eventCount;
Atomic<int64_t> writerWaitCount;
Atomic<State> writerState;
uint8_t padding1[44];
Atomic<int64_t> processedCount;
Atomic<State> readerState;
};
class Helpers {
public:
virtual ~Helpers() = default;
virtual bool InitTranslator(TextureType aTextureType,
gfx::BackendType aBackendType,
Handle&& aReadHandle,
nsTArray<Handle>&& aBufferHandles,
uint64_t aBufferSize,
CrossProcessSemaphoreHandle&& aReaderSem,
CrossProcessSemaphoreHandle&& aWriterSem) = 0;
virtual bool AddBuffer(Handle&& aBufferHandle, uint64_t aBufferSize) = 0;
/**
* @returns true if the reader of the CanvasEventRingBuffer has permanently
* stopped processing, otherwise returns false.
*/
virtual bool ReaderClosed() = 0;
/**
* Causes the reader to resume processing when it is in a stopped state.
*/
virtual bool RestartReader() = 0;
};
bool Init(TextureType aTextureType, gfx::BackendType aBackendType,
UniquePtr<Helpers> aHelpers);
/**
* Record an event for processing by the CanvasParent's CanvasTranslator.
* @param aEvent the event to record
*/
void RecordEvent(const gfx::RecordedEvent& aEvent) final;
void StoreSourceSurfaceRecording(gfx::SourceSurface* aSurface,
const char* aReason) final;
gfx::RecorderType GetRecorderType() const override {
return gfx::RecorderType::CANVAS;
}
void Flush() final { NS_ASSERT_OWNINGTHREAD(CanvasDrawEventRecorder); }
int64_t CreateCheckpoint();
/**
* Waits until the given checkpoint has been read by the translator.
*
* @params aCheckpoint the checkpoint to wait for
* @returns true if the checkpoint was reached, false if the reader is closed
* or we timeout.
*/
bool WaitForCheckpoint(int64_t aCheckpoint);
TextureType GetTextureType() { return mTextureType; }
void DropFreeBuffers();
void ClearProcessedExternalSurfaces();
protected:
gfx::ContiguousBuffer& GetContiguousBuffer(size_t aSize) final;
void IncrementEventCount() final;
private:
void WriteInternalEvent(EventType aEventType);
void CheckAndSignalReader();
size_t mDefaultBufferSize;
size_t mMaxDefaultBuffers;
uint32_t mMaxSpinCount;
uint32_t mDropBufferLimit;
uint32_t mDropBufferOnZero;
UniquePtr<Helpers> mHelpers;
TextureType mTextureType = TextureType::Unknown;
RefPtr<ipc::SharedMemoryBasic> mHeaderShmem;
Header* mHeader = nullptr;
struct CanvasBuffer : public gfx::ContiguousBuffer {
RefPtr<ipc::SharedMemoryBasic> shmem;
CanvasBuffer() : ContiguousBuffer(nullptr) {}
explicit CanvasBuffer(RefPtr<ipc::SharedMemoryBasic>&& aShmem)
: ContiguousBuffer(static_cast<char*>(aShmem->memory()),
aShmem->Size()),
shmem(std::move(aShmem)) {}
size_t Capacity() { return shmem ? shmem->Size() : 0; }
};
struct RecycledBuffer {
RefPtr<ipc::SharedMemoryBasic> shmem;
int64_t eventCount = 0;
explicit RecycledBuffer(RefPtr<ipc::SharedMemoryBasic>&& aShmem,
int64_t aEventCount)
: shmem(std::move(aShmem)), eventCount(aEventCount) {}
size_t Capacity() { return shmem->Size(); }
};
CanvasBuffer mCurrentBuffer;
std::queue<RecycledBuffer> mRecycledBuffers;
UniquePtr<CrossProcessSemaphore> mWriterSemaphore;
UniquePtr<CrossProcessSemaphore> mReaderSemaphore;
};
} // namespace layers
} // namespace mozilla
#endif // mozilla_layers_CanvasDrawEventRecorder_h
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