Bug 1855742 - Part 2. Allow CanvasDrawEventRecorder to be created on DOM workers. r=gfx-reviewers,lsalzman

Differential Revision: https://phabricator.services.mozilla.com/D189530

gfx/2d/2D.h

@@ -1987,7 +1987,7 @@ class DrawTarget : public external::AtomicRefCounted<DrawTarget> {
   SurfaceFormat mFormat;
 };
 
-class DrawEventRecorder : public RefCounted<DrawEventRecorder> {
+class DrawEventRecorder : public external::AtomicRefCounted<DrawEventRecorder> {
  public:
   MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(DrawEventRecorder)
   virtual RecorderType GetRecorderType() const { return RecorderType::UNKNOWN; }

gfx/2d/DrawEventRecorder.cpp

@@ -16,9 +16,7 @@ namespace gfx {
 
 DrawEventRecorderPrivate::DrawEventRecorderPrivate() : mExternalFonts(false) {}
 
-DrawEventRecorderPrivate::~DrawEventRecorderPrivate() {
+DrawEventRecorderPrivate::~DrawEventRecorderPrivate() = default;
-  NS_ASSERT_OWNINGTHREAD(DrawEventRecorderPrivate);
-}
 
 void DrawEventRecorderPrivate::SetDrawTarget(ReferencePtr aDT) {
   NS_ASSERT_OWNINGTHREAD(DrawEventRecorderPrivate);

gfx/2d/DrawEventRecorder.h

@@ -41,7 +41,7 @@ class DrawEventRecorderPrivate : public DrawEventRecorder {
     return true;
   }
   virtual void FlushItem(IntRect) {}
-  void DetachResources() {
+  virtual void DetachResources() {
     NS_ASSERT_OWNINGTHREAD(DrawEventRecorderPrivate);
 
     nsTHashSet<ScaledFont*> fonts = std::move(mStoredFonts);
@@ -116,7 +116,7 @@ class DrawEventRecorderPrivate : public DrawEventRecorder {
     return mStoredObjects.EnsureInserted(aObject);
   }
 
-  void AddPendingDeletion(std::function<void()>&& aPendingDeletion) {
+  virtual void AddPendingDeletion(std::function<void()>&& aPendingDeletion) {
     auto lockedPendingDeletions = mPendingDeletions.Lock();
     lockedPendingDeletions->emplace_back(std::move(aPendingDeletion));
   }

gfx/ipc/CanvasManagerChild.cpp

@@ -224,8 +224,9 @@ RefPtr<layers::CanvasChild> CanvasManagerChild::GetCanvasChild() {
   }
 
   if (!mCanvasChild) {
-    mCanvasChild = MakeAndAddRef<layers::CanvasChild>();
+    mCanvasChild = MakeAndAddRef<layers::CanvasChild>(mWorkerRef);
     if (!SendPCanvasConstructor(mCanvasChild)) {
+      mCanvasChild->Destroy();
       mCanvasChild = nullptr;
     }
   }

gfx/layers/CanvasDrawEventRecorder.cpp

@@ -8,6 +8,11 @@
 
 #include <string.h>
 
+#include "mozilla/dom/WorkerCommon.h"
+#include "mozilla/dom/WorkerPrivate.h"
+#include "mozilla/dom/WorkerRef.h"
+#include "mozilla/dom/WorkerRunnable.h"
+#include "mozilla/layers/TextureRecorded.h"
 #include "mozilla/layers/SharedSurfacesChild.h"
 #include "mozilla/StaticPrefs_gfx.h"
 #include "RecordedCanvasEventImpl.h"
@@ -34,7 +39,9 @@ static Maybe<ShmemAndHandle> CreateAndMapShmem(size_t aSize) {
   return Some(ShmemAndHandle{shmem.forget(), std::move(shmemHandle)});
 }
 
-CanvasDrawEventRecorder::CanvasDrawEventRecorder() {
+CanvasDrawEventRecorder::CanvasDrawEventRecorder(
+    dom::ThreadSafeWorkerRef* aWorkerRef)
+    : mWorkerRef(aWorkerRef), mIsOnWorker(!!aWorkerRef) {
   mDefaultBufferSize = ipc::SharedMemory::PageAlignedSize(
       StaticPrefs::gfx_canvas_remote_default_buffer_size());
   mMaxDefaultBuffers = StaticPrefs::gfx_canvas_remote_max_default_buffers();
@@ -43,6 +50,8 @@ CanvasDrawEventRecorder::CanvasDrawEventRecorder() {
   mDropBufferOnZero = mDropBufferLimit;
 }
 
+CanvasDrawEventRecorder::~CanvasDrawEventRecorder() { MOZ_ASSERT(!mWorkerRef); }
+
 bool CanvasDrawEventRecorder::Init(TextureType aTextureType,
                                    gfx::BackendType aBackendType,
                                    UniquePtr<Helpers> aHelpers) {
@@ -317,6 +326,106 @@ void CanvasDrawEventRecorder::CheckAndSignalReader() {
   } while (true);
 }
 
+void CanvasDrawEventRecorder::DetachResources() {
+  NS_ASSERT_OWNINGTHREAD(CanvasDrawEventRecorder);
+
+  DrawEventRecorderPrivate::DetachResources();
+
+  {
+    auto lockedPendingDeletions = mPendingDeletions.Lock();
+    mWorkerRef = nullptr;
+  }
+}
+
+void CanvasDrawEventRecorder::QueueProcessPendingDeletionsLocked(
+    RefPtr<CanvasDrawEventRecorder>&& aRecorder) {
+  if (!mWorkerRef) {
+    MOZ_RELEASE_ASSERT(
+        !mIsOnWorker,
+        "QueueProcessPendingDeletionsLocked called after worker shutdown!");
+
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "CanvasDrawEventRecorder::QueueProcessPendingDeletionsLocked",
+        [self = std::move(aRecorder)]() { self->ProcessPendingDeletions(); }));
+    return;
+  }
+
+  if (!NS_IsMainThread()) {
+    NS_DispatchToMainThread(NS_NewRunnableFunction(
+        "CanvasDrawEventRecorder::QueueProcessPendingDeletionsLocked",
+        [self = std::move(aRecorder)]() mutable {
+          self->QueueProcessPendingDeletions(std::move(self));
+        }));
+    return;
+  }
+
+  class ProcessPendingRunnable final : public dom::WorkerRunnable {
+   public:
+    ProcessPendingRunnable(dom::WorkerPrivate* aWorkerPrivate,
+                           RefPtr<CanvasDrawEventRecorder>&& aRecorder)
+        : dom::WorkerRunnable(aWorkerPrivate),
+          mRecorder(std::move(aRecorder)) {}
+
+    bool WorkerRun(JSContext*, dom::WorkerPrivate*) override {
+      RefPtr<CanvasDrawEventRecorder> recorder = std::move(mRecorder);
+      recorder->ProcessPendingDeletions();
+      return true;
+    }
+
+   private:
+    RefPtr<CanvasDrawEventRecorder> mRecorder;
+  };
+
+  auto task = MakeRefPtr<ProcessPendingRunnable>(mWorkerRef->Private(),
+                                                 std::move(aRecorder));
+  if (NS_WARN_IF(!task->Dispatch())) {
+    MOZ_CRASH("ProcessPendingRunnable leaked!");
+  }
+}
+
+void CanvasDrawEventRecorder::QueueProcessPendingDeletions(
+    RefPtr<CanvasDrawEventRecorder>&& aRecorder) {
+  auto lockedPendingDeletions = mPendingDeletions.Lock();
+  if (lockedPendingDeletions->empty()) {
+    // We raced to handle the deletions, and something got there first.
+    return;
+  }
+
+  QueueProcessPendingDeletionsLocked(std::move(aRecorder));
+}
+
+void CanvasDrawEventRecorder::AddPendingDeletion(
+    std::function<void()>&& aPendingDeletion) {
+  PendingDeletionsVector pendingDeletions;
+
+  {
+    auto lockedPendingDeletions = mPendingDeletions.Lock();
+    bool wasEmpty = lockedPendingDeletions->empty();
+    lockedPendingDeletions->emplace_back(std::move(aPendingDeletion));
+
+    MOZ_RELEASE_ASSERT(!mIsOnWorker || mWorkerRef,
+                       "AddPendingDeletion called after worker shutdown!");
+
+    // If we are not on the owning thread, we must queue an event to run the
+    // deletions, if we transitioned from empty to non-empty.
+    if ((mWorkerRef && !mWorkerRef->Private()->IsOnCurrentThread()) ||
+        (!mWorkerRef && !NS_IsMainThread())) {
+      if (wasEmpty) {
+        RefPtr<CanvasDrawEventRecorder> self(this);
+        QueueProcessPendingDeletionsLocked(std::move(self));
+      }
+      return;
+    }
+
+    // Otherwise, we can just run all of them right now.
+    pendingDeletions.swap(*lockedPendingDeletions);
+  }
+
+  for (const auto& pendingDeletion : pendingDeletions) {
+    pendingDeletion();
+  }
+}
+
 void CanvasDrawEventRecorder::StoreSourceSurfaceRecording(
     gfx::SourceSurface* aSurface, const char* aReason) {
   NS_ASSERT_OWNINGTHREAD(CanvasDrawEventRecorder);

gfx/layers/CanvasDrawEventRecorder.h

@@ -21,6 +21,10 @@ namespace mozilla {
 
 using EventType = gfx::RecordedEvent::EventType;
 
+namespace dom {
+class ThreadSafeWorkerRef;
+}
+
 namespace layers {
 
 typedef mozilla::ipc::SharedMemoryBasic::Handle Handle;
@@ -31,7 +35,8 @@ class CanvasDrawEventRecorder final : public gfx::DrawEventRecorderPrivate,
  public:
   MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(CanvasDrawEventRecorder, final)
 
-  CanvasDrawEventRecorder();
+  explicit CanvasDrawEventRecorder(dom::ThreadSafeWorkerRef* aWorkerRef);
+  ~CanvasDrawEventRecorder() override;
 
   enum class State : uint32_t {
     Processing,
@@ -98,6 +103,10 @@ class CanvasDrawEventRecorder final : public gfx::DrawEventRecorderPrivate,
    */
   void RecordEvent(const gfx::RecordedEvent& aEvent) final;
 
+  void DetachResources() final;
+
+  void AddPendingDeletion(std::function<void()>&& aPendingDeletion) override;
+
   void StoreSourceSurfaceRecording(gfx::SourceSurface* aSurface,
                                    const char* aReason) final;
 
@@ -134,6 +143,11 @@ class CanvasDrawEventRecorder final : public gfx::DrawEventRecorderPrivate,
 
   void CheckAndSignalReader();
 
+  void QueueProcessPendingDeletions(
+      RefPtr<CanvasDrawEventRecorder>&& aRecorder);
+  void QueueProcessPendingDeletionsLocked(
+      RefPtr<CanvasDrawEventRecorder>&& aRecorder);
+
   size_t mDefaultBufferSize;
   size_t mMaxDefaultBuffers;
   uint32_t mMaxSpinCount;
@@ -173,6 +187,9 @@ class CanvasDrawEventRecorder final : public gfx::DrawEventRecorderPrivate,
 
   UniquePtr<CrossProcessSemaphore> mWriterSemaphore;
   UniquePtr<CrossProcessSemaphore> mReaderSemaphore;
+
+  RefPtr<dom::ThreadSafeWorkerRef> mWorkerRef;
+  bool mIsOnWorker = false;
 };
 
 }  // namespace layers

gfx/layers/ipc/CanvasChild.cpp

@@ -7,6 +7,7 @@
 #include "CanvasChild.h"
 
 #include "MainThreadUtils.h"
+#include "mozilla/dom/WorkerRef.h"
 #include "mozilla/gfx/CanvasManagerChild.h"
 #include "mozilla/gfx/DrawTargetRecording.h"
 #include "mozilla/gfx/Tools.h"
@@ -165,9 +166,10 @@ class SourceSurfaceCanvasRecording final : public gfx::SourceSurface {
   bool mDetached = false;
 };
 
-CanvasChild::CanvasChild() = default;
+CanvasChild::CanvasChild(dom::ThreadSafeWorkerRef* aWorkerRef)
+    : mWorkerRef(aWorkerRef) {}
 
-CanvasChild::~CanvasChild() = default;
+CanvasChild::~CanvasChild() { MOZ_ASSERT(!mWorkerRef); }
 
 static void NotifyCanvasDeviceReset() {
   nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
@@ -213,7 +215,7 @@ void CanvasChild::EnsureRecorder(gfx::IntSize aSize, gfx::SurfaceFormat aFormat,
   if (!mRecorder) {
     gfx::BackendType backendType =
         gfxPlatform::GetPlatform()->GetPreferredCanvasBackend();
-    auto recorder = MakeRefPtr<CanvasDrawEventRecorder>();
+    auto recorder = MakeRefPtr<CanvasDrawEventRecorder>(mWorkerRef);
     if (!recorder->Init(aTextureType, backendType,
                         MakeUnique<RecorderHelpers>(this))) {
       return;
@@ -242,6 +244,8 @@ void CanvasChild::Destroy() {
   if (CanSend()) {
     Send__delete__(this);
   }
+
+  mWorkerRef = nullptr;
 }
 
 bool CanvasChild::EnsureBeginTransaction() {

gfx/layers/ipc/CanvasChild.h

@@ -15,6 +15,10 @@
 
 namespace mozilla {
 
+namespace dom {
+class ThreadSafeWorkerRef;
+}
+
 namespace gfx {
 class DrawTargetRecording;
 class SourceSurface;
@@ -28,7 +32,7 @@ class CanvasChild final : public PCanvasChild, public SupportsWeakPtr {
  public:
   NS_INLINE_DECL_REFCOUNTING(CanvasChild)
 
-  CanvasChild();
+  explicit CanvasChild(dom::ThreadSafeWorkerRef* aWorkerRef);
 
   /**
    * @returns true if remote canvas has been deactivated due to failure.
@@ -173,6 +177,7 @@ class CanvasChild final : public PCanvasChild, public SupportsWeakPtr {
 
   static bool mDeactivated;
 
+  RefPtr<dom::ThreadSafeWorkerRef> mWorkerRef;
   RefPtr<CanvasDrawEventRecorder> mRecorder;
 
   RefPtr<ipc::SharedMemoryBasic> mDataSurfaceShmem;