1 files changed, 195 insertions, 0 deletions
diff --git a/gfx/layers/ipc/CanvasChild.h b/gfx/layers/ipc/CanvasChild.h
new file mode 100644
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+++ b/gfx/layers/ipc/CanvasChild.h
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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 https://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_layers_CanvasChild_h
+#define mozilla_layers_CanvasChild_h
+
+#include "mozilla/gfx/RecordedEvent.h"
+#include "mozilla/ipc/CrossProcessSemaphore.h"
+#include "mozilla/layers/PCanvasChild.h"
+#include "mozilla/layers/SourceSurfaceSharedData.h"
+#include "mozilla/WeakPtr.h"
+
+namespace mozilla {
+
+namespace gfx {
+class DrawTargetRecording;
+class SourceSurface;
+}
+
+namespace layers {
+class CanvasDrawEventRecorder;
+struct RemoteTextureOwnerId;
+
+class CanvasChild final : public PCanvasChild, public SupportsWeakPtr {
+ public:
+  NS_INLINE_DECL_REFCOUNTING(CanvasChild)
+
+  CanvasChild();
+
+  /**
+   * @returns true if remote canvas has been deactivated due to failure.
+   */
+  static bool Deactivated() { return mDeactivated; }
+
+  /**
+   * Release resources until they are next required.
+   */
+  void ClearCachedResources();
+
+  ipc::IPCResult RecvNotifyDeviceChanged();
+
+  ipc::IPCResult RecvDeactivate();
+
+  ipc::IPCResult RecvBlockCanvas();
+
+  ipc::IPCResult RecvNotifyRequiresRefresh(int64_t aTextureId);
+
+  ipc::IPCResult RecvSnapshotShmem(int64_t aTextureId, Handle&& aShmemHandle,
+                                   uint32_t aShmemSize,
+                                   SnapshotShmemResolver&& aResolve);
+
+  /**
+   * Ensures that the DrawEventRecorder has been created.
+   *
+   * @params aTextureType the TextureType to create in the CanvasTranslator.
+   */
+  void EnsureRecorder(gfx::IntSize aSize, gfx::SurfaceFormat aFormat,
+                      TextureType aTextureType);
+
+  /**
+   * Clean up IPDL actor.
+   */
+  void Destroy();
+
+  /**
+   * @returns true if we should be caching data surfaces in the GPU process.
+   */
+  bool ShouldCacheDataSurface() const {
+    return mTransactionsSinceGetDataSurface < kCacheDataSurfaceThreshold;
+  }
+
+  /**
+   * Ensures that we have sent a begin transaction event, since the last
+   * end transaction.
+   * @returns false on failure to begin transaction
+   */
+  bool EnsureBeginTransaction();
+
+  /**
+   * Send an end transaction event to indicate the end of events for this frame.
+   */
+  void EndTransaction();
+
+  /**
+   * @returns true if the canvas IPC classes have not been used for some time
+   *          and can be cleaned up.
+   */
+  bool ShouldBeCleanedUp() const;
+
+  /**
+   * Create a DrawTargetRecording for a canvas texture.
+   * @param aTextureId the id of the new texture
+   * @param aSize size for the DrawTarget
+   * @param aFormat SurfaceFormat for the DrawTarget
+   * @returns newly created DrawTargetRecording
+   */
+  already_AddRefed<gfx::DrawTargetRecording> CreateDrawTarget(
+      int64_t aTextureId, const RemoteTextureOwnerId& aTextureOwnerId,
+      gfx::IntSize aSize, gfx::SurfaceFormat aFormat);
+
+  /**
+   * Record an event for processing by the CanvasParent's CanvasTranslator.
+   * @param aEvent the event to record
+   */
+  void RecordEvent(const gfx::RecordedEvent& aEvent);
+
+  int64_t CreateCheckpoint();
+
+  /**
+   * Wrap the given surface, so that we can provide a DataSourceSurface if
+   * required.
+   * @param aSurface the SourceSurface to wrap
+   * @param aTextureId the texture id of the source TextureData
+   * @returns a SourceSurface that can provide a DataSourceSurface if required
+   */
+  already_AddRefed<gfx::SourceSurface> WrapSurface(
+      const RefPtr<gfx::SourceSurface>& aSurface, int64_t aTextureId);
+
+  /**
+   * The DrawTargetRecording backing the surface has not been modified since the
+   * previous use, so it is safe to reattach the snapshot for readback.
+   */
+  void AttachSurface(const RefPtr<gfx::SourceSurface>& aSurface);
+
+  /**
+   * The DrawTargetRecording is about to change, so detach the old snapshot.
+   */
+  void DetachSurface(const RefPtr<gfx::SourceSurface>& aSurface);
+
+  /**
+   * Get DataSourceSurface from the translated equivalent version of aSurface in
+   * the GPU process.
+   * @param aTextureId the source TextureData to read from
+   * @param aSurface the SourceSurface in this process for which we need a
+   *                 DataSourceSurface
+   * @param aDetached whether the surface is old
+   * @returns a DataSourceSurface created from data for aSurface retrieve from
+   *          GPU process
+   */
+  already_AddRefed<gfx::DataSourceSurface> GetDataSurface(
+      int64_t aTextureId, const gfx::SourceSurface* aSurface, bool aDetached);
+
+  bool RequiresRefresh(int64_t aTextureId) const;
+
+  void CleanupTexture(int64_t aTextureId);
+
+ protected:
+  void ActorDestroy(ActorDestroyReason aWhy) final;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(CanvasChild);
+
+  ~CanvasChild() final;
+
+  bool EnsureDataSurfaceShmem(gfx::IntSize aSize, gfx::SurfaceFormat aFormat);
+
+  void ReturnDataSurfaceShmem(
+      already_AddRefed<ipc::SharedMemoryBasic> aDataSurfaceShmem);
+
+  struct DataShmemHolder {
+    RefPtr<ipc::SharedMemoryBasic> shmem;
+    RefPtr<CanvasChild> canvasChild;
+  };
+
+  static void ReleaseDataShmemHolder(void* aClosure);
+
+  void DropFreeBuffersWhenDormant();
+
+  static const uint32_t kCacheDataSurfaceThreshold = 10;
+
+  static bool mDeactivated;
+
+  RefPtr<CanvasDrawEventRecorder> mRecorder;
+
+  RefPtr<ipc::SharedMemoryBasic> mDataSurfaceShmem;
+  bool mDataSurfaceShmemAvailable = false;
+  int64_t mLastWriteLockCheckpoint = 0;
+  uint32_t mTransactionsSinceGetDataSurface = kCacheDataSurfaceThreshold;
+  struct TextureInfo {
+    RefPtr<mozilla::ipc::SharedMemoryBasic> mSnapshotShmem;
+    bool mRequiresRefresh = false;
+  };
+  std::unordered_map<int64_t, TextureInfo> mTextureInfo;
+  bool mIsInTransaction = false;
+  bool mDormant = false;
+  bool mBlocked = false;
+};
+
+}  // namespace layers
+}  // namespace mozilla
+
+#endif  // mozilla_layers_CanvasChild_h