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-rw-r--r--dom/media/CanvasCaptureMediaStream.h132
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diff --git a/dom/media/CanvasCaptureMediaStream.h b/dom/media/CanvasCaptureMediaStream.h
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
+/* 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_CanvasCaptureMediaStream_h_
+#define mozilla_dom_CanvasCaptureMediaStream_h_
+
+#include "DOMMediaStream.h"
+#include "mozilla/dom/HTMLCanvasElement.h"
+#include "PrincipalHandle.h"
+
+class nsIPrincipal;
+
+namespace mozilla {
+class DOMMediaStream;
+class SourceMediaTrack;
+
+namespace layers {
+class Image;
+} // namespace layers
+
+namespace dom {
+class CanvasCaptureMediaStream;
+class HTMLCanvasElement;
+class OutputStreamFrameListener;
+
+/*
+ * The CanvasCaptureMediaStream is a MediaStream subclass that provides a video
+ * track containing frames from a canvas. See an architectural overview below.
+ *
+ * ----------------------------------------------------------------------------
+ * === Main Thread === __________________________
+ * | |
+ * | CanvasCaptureMediaStream |
+ * |__________________________|
+ * |
+ * | RequestFrame()
+ * v
+ * ________________________
+ * ________ FrameCaptureRequested? | |
+ * | | ------------------------> | OutputStreamDriver |
+ * | Canvas | SetFrameCapture() | (FrameCaptureListener) |
+ * |________| ------------------------> |________________________|
+ * |
+ * | SetImage() -
+ * | AppendToTrack()
+ * |
+ * v
+ * __________________________
+ * | |
+ * | MTG / SourceMediaTrack |
+ * |__________________________|
+ * ----------------------------------------------------------------------------
+ */
+
+/*
+ * Base class for drivers of the output stream.
+ * It is up to each sub class to implement the NewFrame() callback of
+ * FrameCaptureListener.
+ */
+class OutputStreamDriver : public FrameCaptureListener {
+ public:
+ OutputStreamDriver(SourceMediaTrack* aSourceStream,
+ const PrincipalHandle& aPrincipalHandle);
+
+ NS_INLINE_DECL_THREADSAFE_REFCOUNTING(OutputStreamDriver);
+
+ /*
+ * Called from js' requestFrame() when it wants the next painted frame to be
+ * explicitly captured.
+ */
+ virtual void RequestFrameCapture() = 0;
+
+ /*
+ * Sub classes can SetImage() to update the image being appended to the
+ * output stream. It will be appended on the next NotifyPull from MTG.
+ */
+ void SetImage(RefPtr<layers::Image>&& aImage, const TimeStamp& aTime);
+
+ /*
+ * Ends the track in mSourceStream when we know there won't be any more images
+ * requested for it.
+ */
+ void EndTrack();
+
+ const RefPtr<SourceMediaTrack> mSourceStream;
+ const PrincipalHandle mPrincipalHandle;
+
+ protected:
+ virtual ~OutputStreamDriver();
+};
+
+class CanvasCaptureMediaStream : public DOMMediaStream {
+ public:
+ CanvasCaptureMediaStream(nsPIDOMWindowInner* aWindow,
+ HTMLCanvasElement* aCanvas);
+
+ NS_DECL_ISUPPORTS_INHERITED
+ NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(CanvasCaptureMediaStream,
+ DOMMediaStream)
+
+ nsresult Init(const dom::Optional<double>& aFPS, nsIPrincipal* aPrincipal);
+
+ JSObject* WrapObject(JSContext* aCx,
+ JS::Handle<JSObject*> aGivenProto) override;
+
+ // WebIDL
+ HTMLCanvasElement* Canvas() const { return mCanvas; }
+ void RequestFrame();
+
+ dom::FrameCaptureListener* FrameCaptureListener();
+
+ /**
+ * Stops capturing for this stream at mCanvas.
+ */
+ void StopCapture();
+
+ SourceMediaTrack* GetSourceStream() const;
+
+ protected:
+ ~CanvasCaptureMediaStream();
+
+ private:
+ RefPtr<HTMLCanvasElement> mCanvas;
+ RefPtr<OutputStreamDriver> mOutputStreamDriver;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif /* mozilla_dom_CanvasCaptureMediaStream_h_ */