1 files changed, 204 insertions, 0 deletions
diff --git a/dom/canvas/OffscreenCanvas.h b/dom/canvas/OffscreenCanvas.h
new file mode 100644
index 0000000000..0724b5ab70
--- /dev/null
+++ b/dom/canvas/OffscreenCanvas.h
@@ -0,0 +1,204 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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_DOM_OFFSCREENCANVAS_H_
+#define MOZILLA_DOM_OFFSCREENCANVAS_H_
+
+#include "gfxTypes.h"
+#include "mozilla/dom/CanvasRenderingContextHelper.h"
+#include "mozilla/dom/ImageEncoder.h"
+#include "mozilla/dom/OffscreenCanvasDisplayHelper.h"
+#include "mozilla/DOMEventTargetHelper.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/RefPtr.h"
+#include "nsCycleCollectionParticipant.h"
+
+struct JSContext;
+
+namespace mozilla {
+class CancelableRunnable;
+class ErrorResult;
+enum class RFPTarget : unsigned;
+
+namespace gfx {
+class SourceSurface;
+}
+
+namespace dom {
+enum class OffscreenRenderingContextId : uint8_t;
+class Blob;
+class EncodeCompleteCallback;
+class OffscreenCanvasDisplayHelper;
+class ImageBitmap;
+struct ImageEncodeOptions;
+
+using OwningOffscreenRenderingContext = class
+    OwningOffscreenCanvasRenderingContext2DOrImageBitmapRenderingContextOrWebGLRenderingContextOrWebGL2RenderingContextOrGPUCanvasContext;
+
+// This is helper class for transferring OffscreenCanvas to worker thread.
+// Because OffscreenCanvas is not thread-safe. So we cannot pass Offscreen-
+// Canvas to worker thread directly. Thus, we create this helper class and
+// store necessary data in it then pass it to worker thread.
+struct OffscreenCanvasCloneData final {
+  OffscreenCanvasCloneData(OffscreenCanvasDisplayHelper* aDisplay,
+                           uint32_t aWidth, uint32_t aHeight,
+                           layers::LayersBackend aCompositorBackend,
+                           layers::TextureType aTextureType, bool aNeutered,
+                           bool aIsWriteOnly, nsIPrincipal* aExpandedReader);
+  ~OffscreenCanvasCloneData();
+
+  RefPtr<OffscreenCanvasDisplayHelper> mDisplay;
+  uint32_t mWidth;
+  uint32_t mHeight;
+  layers::LayersBackend mCompositorBackendType;
+  layers::TextureType mTextureType;
+  bool mNeutered;
+  bool mIsWriteOnly;
+  RefPtr<nsIPrincipal> mExpandedReader;
+};
+
+class OffscreenCanvas final : public DOMEventTargetHelper,
+                              public CanvasRenderingContextHelper {
+ public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(OffscreenCanvas,
+                                           DOMEventTargetHelper)
+
+  IMPL_EVENT_HANDLER(contextlost);
+  IMPL_EVENT_HANDLER(contextrestored);
+
+  OffscreenCanvas(nsIGlobalObject* aGlobal, uint32_t aWidth, uint32_t aHeight);
+
+  OffscreenCanvas(nsIGlobalObject* aGlobal, uint32_t aWidth, uint32_t aHeight,
+                  layers::LayersBackend aCompositorBackend,
+                  layers::TextureType aTextureType,
+                  already_AddRefed<OffscreenCanvasDisplayHelper> aDisplay);
+
+  nsIGlobalObject* GetParentObject() const { return GetOwnerGlobal(); }
+
+  virtual JSObject* WrapObject(JSContext* aCx,
+                               JS::Handle<JSObject*> aGivenProto) override;
+
+  static already_AddRefed<OffscreenCanvas> Constructor(
+      const GlobalObject& aGlobal, uint32_t aWidth, uint32_t aHeight,
+      ErrorResult& aRv);
+
+  void ClearResources();
+
+  uint32_t Width() const { return mWidth; }
+  uint32_t Height() const { return mHeight; }
+  void SetWidth(uint32_t aWidth, ErrorResult& aRv);
+  void SetHeight(uint32_t aHeight, ErrorResult& aRv);
+
+  void GetContext(JSContext* aCx, const OffscreenRenderingContextId& aContextId,
+                  JS::Handle<JS::Value> aContextOptions,
+                  Nullable<OwningOffscreenRenderingContext>& aResult,
+                  ErrorResult& aRv);
+
+  already_AddRefed<ImageBitmap> TransferToImageBitmap(ErrorResult& aRv);
+
+  already_AddRefed<Promise> ConvertToBlob(const ImageEncodeOptions& aOptions,
+                                          ErrorResult& aRv);
+
+  already_AddRefed<Promise> ToBlob(JSContext* aCx, const nsAString& aType,
+                                   JS::Handle<JS::Value> aParams,
+                                   ErrorResult& aRv);
+
+  nsICanvasRenderingContextInternal* GetContext() const {
+    return mCurrentContext;
+  }
+
+  CanvasContextType GetContextType() const { return mCurrentContextType; }
+
+  already_AddRefed<gfx::SourceSurface> GetSurfaceSnapshot(
+      gfxAlphaType* aOutAlphaType = nullptr);
+
+  static already_AddRefed<OffscreenCanvas> CreateFromCloneData(
+      nsIGlobalObject* aGlobal, OffscreenCanvasCloneData* aData);
+
+  // Return true on main-thread, and return gfx.offscreencanvas.enabled
+  // on worker thread.
+  static bool PrefEnabledOnWorkerThread(JSContext* aCx, JSObject* aObj);
+
+  OffscreenCanvasCloneData* ToCloneData();
+
+  void UpdateDisplayData(const OffscreenCanvasDisplayData& aData);
+
+  void CommitFrameToCompositor();
+  void DequeueCommitToCompositor();
+  void QueueCommitToCompositor();
+
+  virtual bool GetOpaqueAttr() override { return false; }
+
+  virtual nsIntSize GetWidthHeight() override {
+    return nsIntSize(mWidth, mHeight);
+  }
+
+  virtual already_AddRefed<nsICanvasRenderingContextInternal> CreateContext(
+      CanvasContextType aContextType) override;
+
+  void SetNeutered() {
+    mWidth = 0;
+    mHeight = 0;
+    mNeutered = true;
+  }
+
+  bool MayNeuter() const { return !mNeutered && !mCurrentContext; }
+
+  nsIPrincipal* GetExpandedReader() const { return mExpandedReader; }
+
+  void SetWriteOnly(RefPtr<nsIPrincipal>&& aExpandedReader);
+
+  void SetWriteOnly(nsIPrincipal* aExpandedReader = nullptr) {
+    RefPtr<nsIPrincipal> expandedReader(aExpandedReader);
+    SetWriteOnly(std::move(expandedReader));
+  }
+
+  bool IsWriteOnly() const { return mIsWriteOnly; }
+
+  // Determines if the caller should be able to read the content.
+  bool CallerCanRead(nsIPrincipal* aPrincipal) const;
+
+  layers::LayersBackend GetCompositorBackendType() const {
+    return mCompositorBackendType;
+  }
+
+  bool ShouldResistFingerprinting(mozilla::RFPTarget aTarget) const;
+
+  bool IsTransferredFromElement() const { return !!mDisplay; }
+
+ private:
+  ~OffscreenCanvas();
+
+  already_AddRefed<EncodeCompleteCallback> CreateEncodeCompleteCallback(
+      Promise* aPromise);
+
+  void CanvasAttrChanged() {
+    ErrorResult dummy;
+    UpdateContext(nullptr, JS::NullHandleValue, dummy);
+  }
+
+  bool mNeutered = false;
+  bool mIsWriteOnly = false;
+
+  uint32_t mWidth = 0;
+  uint32_t mHeight = 0;
+
+  layers::LayersBackend mCompositorBackendType =
+      layers::LayersBackend::LAYERS_NONE;
+  layers::TextureType mTextureType = layers::TextureType::Unknown;
+
+  RefPtr<OffscreenCanvasDisplayHelper> mDisplay;
+  RefPtr<CancelableRunnable> mPendingCommit;
+  RefPtr<nsIPrincipal> mExpandedReader;
+  Maybe<OffscreenCanvasDisplayData> mPendingUpdate;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // MOZILLA_DOM_OFFSCREENCANVAS_H_