1 files changed, 436 insertions, 0 deletions
diff --git a/dom/html/HTMLCanvasElement.h b/dom/html/HTMLCanvasElement.h
new file mode 100644
index 0000000000..bc2600779f
--- /dev/null
+++ b/dom/html/HTMLCanvasElement.h
@@ -0,0 +1,436 @@
+/* -*- 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/. */
+#if !defined(mozilla_dom_HTMLCanvasElement_h)
+#  define mozilla_dom_HTMLCanvasElement_h
+
+#  include "mozilla/Attributes.h"
+#  include "mozilla/StateWatching.h"
+#  include "mozilla/WeakPtr.h"
+#  include "nsIDOMEventListener.h"
+#  include "nsIObserver.h"
+#  include "nsGenericHTMLElement.h"
+#  include "nsGkAtoms.h"
+#  include "nsSize.h"
+#  include "nsError.h"
+
+#  include "mozilla/dom/CanvasRenderingContextHelper.h"
+#  include "mozilla/gfx/Rect.h"
+#  include "mozilla/layers/LayersTypes.h"
+
+class nsICanvasRenderingContextInternal;
+class nsIInputStream;
+class nsITimerCallback;
+enum class gfxAlphaType;
+enum class FrameCaptureState : uint8_t;
+
+namespace mozilla {
+
+class nsDisplayListBuilder;
+class ClientWebGLContext;
+
+namespace layers {
+class CanvasRenderer;
+class Image;
+class ImageContainer;
+class Layer;
+class LayerManager;
+class OOPCanvasRenderer;
+class SharedSurfaceTextureClient;
+class WebRenderCanvasData;
+}  // namespace layers
+namespace gfx {
+class DrawTarget;
+class SourceSurface;
+class VRLayerChild;
+}  // namespace gfx
+namespace webgpu {
+class CanvasContext;
+}  // namespace webgpu
+
+namespace dom {
+class BlobCallback;
+class CanvasCaptureMediaStream;
+class File;
+class HTMLCanvasPrintState;
+class OffscreenCanvas;
+class OffscreenCanvasDisplayHelper;
+class PrintCallback;
+class PWebGLChild;
+class RequestedFrameRefreshObserver;
+
+// Listen visibilitychange and memory-pressure event and inform
+// context when event is fired.
+class HTMLCanvasElementObserver final : public nsIObserver {
+ public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+  explicit HTMLCanvasElementObserver(HTMLCanvasElement* aElement);
+  void Destroy();
+
+  void RegisterObserverEvents();
+  void UnregisterObserverEvents();
+
+ private:
+  ~HTMLCanvasElementObserver();
+
+  HTMLCanvasElement* mElement;
+};
+
+/*
+ * FrameCaptureListener is used by captureStream() as a way of getting video
+ * frames from the canvas. On a refresh driver tick after something has been
+ * drawn to the canvas since the last such tick, all registered
+ * FrameCaptureListeners that report true for FrameCaptureRequested() will be
+ * given a copy of the just-painted canvas.
+ * All FrameCaptureListeners get the same copy.
+ */
+class FrameCaptureListener : public SupportsWeakPtr {
+ public:
+  FrameCaptureListener() = default;
+
+  /*
+   * Indicates to the canvas whether or not this listener has requested a frame.
+   */
+  virtual bool FrameCaptureRequested(const TimeStamp& aTime) const = 0;
+
+  /*
+   * Interface through which new video frames will be provided while
+   * `mFrameCaptureRequested` is `true`.
+   */
+  virtual void NewFrame(already_AddRefed<layers::Image> aImage,
+                        const TimeStamp& aTime) = 0;
+
+ protected:
+  virtual ~FrameCaptureListener() = default;
+};
+
+class HTMLCanvasElement final : public nsGenericHTMLElement,
+                                public CanvasRenderingContextHelper,
+                                public SupportsWeakPtr {
+  enum { DEFAULT_CANVAS_WIDTH = 300, DEFAULT_CANVAS_HEIGHT = 150 };
+
+  typedef layers::CanvasRenderer CanvasRenderer;
+  typedef layers::LayerManager LayerManager;
+  typedef layers::WebRenderCanvasData WebRenderCanvasData;
+
+ public:
+  explicit HTMLCanvasElement(
+      already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo);
+
+  NS_IMPL_FROMNODE_HTML_WITH_TAG(HTMLCanvasElement, canvas)
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // CC
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(HTMLCanvasElement,
+                                           nsGenericHTMLElement)
+
+  // WebIDL
+  uint32_t Height() {
+    return GetUnsignedIntAttr(nsGkAtoms::height, DEFAULT_CANVAS_HEIGHT);
+  }
+  uint32_t Width() {
+    return GetUnsignedIntAttr(nsGkAtoms::width, DEFAULT_CANVAS_WIDTH);
+  }
+  void SetHeight(uint32_t aHeight, ErrorResult& aRv);
+  void SetWidth(uint32_t aWidth, ErrorResult& aRv);
+
+  already_AddRefed<nsISupports> GetContext(
+      JSContext* aCx, const nsAString& aContextId,
+      JS::Handle<JS::Value> aContextOptions, ErrorResult& aRv);
+
+  void ToDataURL(JSContext* aCx, const nsAString& aType,
+                 JS::Handle<JS::Value> aParams, nsAString& aDataURL,
+                 nsIPrincipal& aSubjectPrincipal, ErrorResult& aRv);
+
+  void ToBlob(JSContext* aCx, BlobCallback& aCallback, const nsAString& aType,
+              JS::Handle<JS::Value> aParams, nsIPrincipal& aSubjectPrincipal,
+              ErrorResult& aRv);
+
+  OffscreenCanvas* TransferControlToOffscreen(ErrorResult& aRv);
+
+  bool MozOpaque() const { return GetBoolAttr(nsGkAtoms::moz_opaque); }
+  void SetMozOpaque(bool aValue, ErrorResult& aRv) {
+    if (mOffscreenCanvas) {
+      aRv.Throw(NS_ERROR_FAILURE);
+      return;
+    }
+
+    SetHTMLBoolAttr(nsGkAtoms::moz_opaque, aValue, aRv);
+  }
+  PrintCallback* GetMozPrintCallback() const;
+  void SetMozPrintCallback(PrintCallback* aCallback);
+
+  already_AddRefed<CanvasCaptureMediaStream> CaptureStream(
+      const Optional<double>& aFrameRate, nsIPrincipal& aSubjectPrincipal,
+      ErrorResult& aRv);
+
+  /**
+   * Get the size in pixels of this canvas element
+   */
+  nsIntSize GetSize();
+
+  /**
+   * Determine whether the canvas is write-only.
+   */
+  bool IsWriteOnly() const;
+
+  /**
+   * Force the canvas to be write-only, except for readers from
+   * a specific extension's content script expanded principal, if
+   * available.
+   */
+  void SetWriteOnly(nsIPrincipal* aExpandedReader = nullptr);
+
+  /**
+   * Notify the placeholder offscreen canvas of an updated size.
+   */
+  void InvalidateCanvasPlaceholder(uint32_t aWidth, uint32_t aHeight);
+
+  /**
+   * Notify that some canvas content has changed and the window may
+   * need to be updated. aDamageRect is in canvas coordinates.
+   */
+  void InvalidateCanvasContent(const mozilla::gfx::Rect* aDamageRect);
+  /*
+   * Notify that we need to repaint the entire canvas, including updating of
+   * the layer tree.
+   */
+  void InvalidateCanvas();
+
+  nsICanvasRenderingContextInternal* GetCurrentContext() {
+    return mCurrentContext;
+  }
+
+  /*
+   * Returns true if the canvas context content is guaranteed to be opaque
+   * across its entire area.
+   */
+  bool GetIsOpaque();
+  virtual bool GetOpaqueAttr() override;
+
+  /**
+   * Retrieve a snapshot of the internal surface, returning the alpha type if
+   * requested. An optional target may be supplied for which the snapshot will
+   * be optimized for, if possible.
+   */
+  virtual already_AddRefed<gfx::SourceSurface> GetSurfaceSnapshot(
+      gfxAlphaType* aOutAlphaType = nullptr,
+      gfx::DrawTarget* aTarget = nullptr);
+
+  /*
+   * Register a FrameCaptureListener with this canvas.
+   * The canvas hooks into the RefreshDriver while there are
+   * FrameCaptureListeners registered.
+   * The registered FrameCaptureListeners are stored as WeakPtrs, thus it's the
+   * caller's responsibility to keep them alive. Once a registered
+   * FrameCaptureListener is destroyed it will be automatically deregistered.
+   */
+  nsresult RegisterFrameCaptureListener(FrameCaptureListener* aListener,
+                                        bool aReturnPlaceholderData);
+
+  /*
+   * Returns true when there is at least one registered FrameCaptureListener
+   * that has requested a frame capture.
+   */
+  bool IsFrameCaptureRequested(const TimeStamp& aTime) const;
+
+  /*
+   * Processes destroyed FrameCaptureListeners and removes them if necessary.
+   * Should there be none left, the FrameRefreshObserver will be unregistered.
+   */
+  void ProcessDestroyedFrameListeners();
+
+  /*
+   * Called by the RefreshDriver hook when a frame has been captured.
+   * Makes a copy of the provided surface and hands it to all
+   * FrameCaptureListeners having requested frame capture.
+   */
+  void SetFrameCapture(already_AddRefed<gfx::SourceSurface> aSurface,
+                       const TimeStamp& aTime);
+
+  virtual bool ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
+                              const nsAString& aValue,
+                              nsIPrincipal* aMaybeScriptedPrincipal,
+                              nsAttrValue& aResult) override;
+  NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
+  nsChangeHint GetAttributeChangeHint(const nsAtom* aAttribute,
+                                      int32_t aModType) const override;
+  nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
+
+  virtual nsresult Clone(dom::NodeInfo*, nsINode** aResult) const override;
+  nsresult CopyInnerTo(HTMLCanvasElement* aDest);
+
+  static void MapAttributesIntoRule(const nsMappedAttributes* aAttributes,
+                                    MappedDeclarations&);
+
+  /*
+   * Helpers called by various users of Canvas
+   */
+
+  already_AddRefed<layers::Image> GetAsImage();
+  bool UpdateWebRenderCanvasData(nsDisplayListBuilder* aBuilder,
+                                 WebRenderCanvasData* aCanvasData);
+  bool InitializeCanvasRenderer(nsDisplayListBuilder* aBuilder,
+                                CanvasRenderer* aRenderer);
+
+  // Call this whenever we need future changes to the canvas
+  // to trigger fresh invalidation requests. This needs to be called
+  // whenever we render the canvas contents to the screen, or whenever we
+  // take a snapshot of the canvas that needs to be "live" (e.g. -moz-element).
+  void MarkContextClean();
+
+  // Call this after capturing a frame, so we can avoid unnecessary surface
+  // copies for future frames when no drawing has occurred.
+  void MarkContextCleanForFrameCapture();
+
+  // Returns non-null when the current context supports captureStream().
+  // The FrameCaptureState gets set to DIRTY when something is drawn.
+  Watchable<FrameCaptureState>* GetFrameCaptureState();
+
+  nsresult GetContext(const nsAString& aContextId, nsISupports** aContext);
+
+  layers::LayersBackend GetCompositorBackendType() const;
+
+  void OnMemoryPressure();
+  void OnDeviceReset();
+
+  already_AddRefed<layers::SharedSurfaceTextureClient> GetVRFrame();
+  void ClearVRFrame();
+
+  bool MaybeModified() const { return mMaybeModified; };
+
+ protected:
+  virtual ~HTMLCanvasElement();
+  void Destroy();
+
+  virtual JSObject* WrapNode(JSContext* aCx,
+                             JS::Handle<JSObject*> aGivenProto) override;
+
+  virtual nsIntSize GetWidthHeight() override;
+
+  virtual already_AddRefed<nsICanvasRenderingContextInternal> CreateContext(
+      CanvasContextType aContextType) override;
+
+  nsresult ExtractData(JSContext* aCx, nsIPrincipal& aSubjectPrincipal,
+                       nsAString& aType, const nsAString& aOptions,
+                       nsIInputStream** aStream);
+  nsresult ToDataURLImpl(JSContext* aCx, nsIPrincipal& aSubjectPrincipal,
+                         const nsAString& aMimeType,
+                         const JS::Value& aEncoderOptions, nsAString& aDataURL);
+  MOZ_CAN_RUN_SCRIPT void CallPrintCallback();
+
+  virtual void AfterSetAttr(int32_t aNamespaceID, nsAtom* aName,
+                            const nsAttrValue* aValue,
+                            const nsAttrValue* aOldValue,
+                            nsIPrincipal* aSubjectPrincipal,
+                            bool aNotify) override;
+  virtual void OnAttrSetButNotChanged(int32_t aNamespaceID, nsAtom* aName,
+                                      const nsAttrValueOrString& aValue,
+                                      bool aNotify) override;
+
+ public:
+  ClientWebGLContext* GetWebGLContext();
+  webgpu::CanvasContext* GetWebGPUContext();
+
+  bool IsOffscreen() const { return !!mOffscreenCanvas; }
+  OffscreenCanvas* GetOffscreenCanvas() const { return mOffscreenCanvas; }
+  void FlushOffscreenCanvas();
+
+  layers::ImageContainer* GetImageContainer() const { return mImageContainer; }
+
+ protected:
+  bool mResetLayer;
+  bool mMaybeModified;  // we fetched the context, so we may have written to the
+                        // canvas
+  RefPtr<HTMLCanvasElement> mOriginalCanvas;
+  RefPtr<PrintCallback> mPrintCallback;
+  RefPtr<HTMLCanvasPrintState> mPrintState;
+  nsTArray<WeakPtr<FrameCaptureListener>> mRequestedFrameListeners;
+  RefPtr<RequestedFrameRefreshObserver> mRequestedFrameRefreshObserver;
+  RefPtr<CanvasRenderer> mCanvasRenderer;
+  RefPtr<OffscreenCanvas> mOffscreenCanvas;
+  RefPtr<OffscreenCanvasDisplayHelper> mOffscreenDisplay;
+  RefPtr<layers::ImageContainer> mImageContainer;
+  RefPtr<HTMLCanvasElementObserver> mContextObserver;
+
+ public:
+  // Record whether this canvas should be write-only or not.
+  // We set this when script paints an image from a different origin.
+  // We also transitively set it when script paints a canvas which
+  // is itself write-only.
+  bool mWriteOnly;
+
+  // When this canvas is (only) tainted by an image from an extension
+  // content script, allow reads from the same extension afterwards.
+  RefPtr<nsIPrincipal> mExpandedReader;
+
+  // Determines if the caller should be able to read the content.
+  bool CallerCanRead(nsIPrincipal* aPrincipal) const;
+
+  bool IsPrintCallbackDone();
+
+  void HandlePrintCallback(nsPresContext*);
+
+  nsresult DispatchPrintCallback(nsITimerCallback* aCallback);
+
+  void ResetPrintCallback();
+
+  HTMLCanvasElement* GetOriginalCanvas();
+
+  CanvasContextType GetCurrentContextType();
+
+ private:
+  /**
+   * This function is called by AfterSetAttr and OnAttrSetButNotChanged.
+   * This function will be called by AfterSetAttr whether the attribute is being
+   * set or unset.
+   *
+   * @param aNamespaceID the namespace of the attr being set
+   * @param aName the localname of the attribute being set
+   * @param aNotify Whether we plan to notify document observers.
+   */
+  void AfterMaybeChangeAttr(int32_t aNamespaceID, nsAtom* aName, bool aNotify);
+};
+
+class HTMLCanvasPrintState final : public nsWrapperCache {
+ public:
+  HTMLCanvasPrintState(HTMLCanvasElement* aCanvas,
+                       nsICanvasRenderingContextInternal* aContext,
+                       nsITimerCallback* aCallback);
+
+  nsISupports* Context() const;
+
+  void Done();
+
+  void NotifyDone();
+
+  bool mIsDone;
+
+  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(HTMLCanvasPrintState)
+  NS_DECL_CYCLE_COLLECTION_NATIVE_WRAPPERCACHE_CLASS(HTMLCanvasPrintState)
+
+  virtual JSObject* WrapObject(JSContext* cx,
+                               JS::Handle<JSObject*> aGivenProto) override;
+
+  HTMLCanvasElement* GetParentObject() { return mCanvas; }
+
+ private:
+  ~HTMLCanvasPrintState();
+  bool mPendingNotify;
+
+ protected:
+  RefPtr<HTMLCanvasElement> mCanvas;
+  nsCOMPtr<nsICanvasRenderingContextInternal> mContext;
+  nsCOMPtr<nsITimerCallback> mCallback;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif /* mozilla_dom_HTMLCanvasElement_h */