Bug 1032848 - Part 1: Implement WebIDL for HTMLCanvasElement::CaptureStream. r=smaug, r=mt

dom/html/HTMLCanvasElement.cpp

@@ -13,6 +13,7 @@
 #include "mozilla/Assertions.h"
 #include "mozilla/Base64.h"
 #include "mozilla/CheckedInt.h"
+#include "mozilla/dom/CanvasCaptureMediaStream.h"
 #include "mozilla/dom/CanvasRenderingContext2D.h"
 #include "mozilla/dom/File.h"
 #include "mozilla/dom/HTMLCanvasElementBinding.h"
@@ -405,6 +406,14 @@ HTMLCanvasElement::GetMozPrintCallback() const
   return mPrintCallback;
 }
 
+already_AddRefed<CanvasCaptureMediaStream>
+HTMLCanvasElement::CaptureStream(const Optional<double>& aFrameRate,
+                                 ErrorResult& aRv)
+{
+  aRv.Throw(NS_ERROR_NOT_IMPLEMENTED);
+  return nullptr;
+}
+
 nsresult
 HTMLCanvasElement::ExtractData(nsAString& aType,
                                const nsAString& aOptions,

dom/html/HTMLCanvasElement.h

@@ -29,7 +29,7 @@ class SourceSurface;
 }
 
 namespace dom {
-
+class CanvasCaptureMediaStream;
 class File;
 class FileCallback;
 class HTMLCanvasPrintState;
@@ -126,6 +126,9 @@ public:
   PrintCallback* GetMozPrintCallback() const;
   void SetMozPrintCallback(PrintCallback* aCallback);
 
+  already_AddRefed<CanvasCaptureMediaStream>
+  CaptureStream(const Optional<double>& aFrameRate, ErrorResult& aRv);
+
   /**
    * Get the size in pixels of this canvas element
    */

dom/media/CanvasCaptureMediaStream.cpp

@@ -0,0 +1,76 @@
+/* -*- 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/. */
+
+#include "CanvasCaptureMediaStream.h"
+#include "DOMMediaStream.h"
+#include "ImageContainer.h"
+#include "MediaStreamGraph.h"
+#include "mozilla/Mutex.h"
+#include "mozilla/dom/CanvasCaptureMediaStreamBinding.h"
+#include "mozilla/dom/HTMLCanvasElement.h"
+#include "nsIAppShell.h"
+#include "nsWidgetsCID.h"
+
+static NS_DEFINE_CID(kAppShellCID, NS_APPSHELL_CID);
+
+using namespace mozilla::layers;
+using namespace mozilla::gfx;
+
+namespace mozilla {
+namespace dom {
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(CanvasCaptureMediaStream, DOMMediaStream,
+                                   mCanvas)
+
+NS_IMPL_ADDREF_INHERITED(CanvasCaptureMediaStream, DOMMediaStream)
+NS_IMPL_RELEASE_INHERITED(CanvasCaptureMediaStream, DOMMediaStream)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(CanvasCaptureMediaStream)
+NS_INTERFACE_MAP_END_INHERITING(DOMMediaStream)
+
+CanvasCaptureMediaStream::CanvasCaptureMediaStream(HTMLCanvasElement* aCanvas)
+  : mCanvas(aCanvas)
+{
+}
+
+CanvasCaptureMediaStream::~CanvasCaptureMediaStream()
+{
+}
+
+JSObject*
+CanvasCaptureMediaStream::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
+{
+  return dom::CanvasCaptureMediaStreamBinding::Wrap(aCx, this, aGivenProto);
+}
+
+void
+CanvasCaptureMediaStream::RequestFrame()
+{
+}
+
+nsresult
+CanvasCaptureMediaStream::Init(const dom::Optional<double>& aFPS,
+                               const TrackID& aTrackId)
+{
+  if (!aFPS.WasPassed()) {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  } else if (aFPS.Value() < 0) {
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+already_AddRefed<CanvasCaptureMediaStream>
+CanvasCaptureMediaStream::CreateSourceStream(nsIDOMWindow* aWindow,
+                                             HTMLCanvasElement* aCanvas)
+{
+  nsRefPtr<CanvasCaptureMediaStream> stream = new CanvasCaptureMediaStream(aCanvas);
+  stream->InitSourceStream(aWindow);
+  return stream.forget();
+}
+
+} // namespace dom
+} // namespace mozilla
+

dom/media/CanvasCaptureMediaStream.h

@@ -0,0 +1,48 @@
+/* -*- 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_
+
+namespace mozilla {
+class DOMMediaStream;
+
+namespace dom {
+class HTMLCanvasElement;
+
+class CanvasCaptureMediaStream: public DOMMediaStream
+{
+public:
+  explicit CanvasCaptureMediaStream(HTMLCanvasElement* aCanvas);
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(CanvasCaptureMediaStream, DOMMediaStream)
+
+  nsresult Init(const dom::Optional<double>& aFPS, const TrackID& aTrackId);
+
+  virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
+
+  // WebIDL
+  HTMLCanvasElement* Canvas() const { return mCanvas; }
+  void RequestFrame();
+
+  /**
+   * Create a CanvasCaptureMediaStream whose underlying stream is a SourceMediaStream.
+   */
+  static already_AddRefed<CanvasCaptureMediaStream>
+  CreateSourceStream(nsIDOMWindow* aWindow,
+                     HTMLCanvasElement* aCanvas);
+
+protected:
+  ~CanvasCaptureMediaStream();
+
+private:
+  nsRefPtr<HTMLCanvasElement> mCanvas;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif /* mozilla_dom_CanvasCaptureMediaStream_h_ */

dom/media/DOMMediaStream.cpp

@@ -14,6 +14,7 @@
 #include "mozilla/dom/AudioTrackList.h"
 #include "mozilla/dom/VideoTrack.h"
 #include "mozilla/dom/VideoTrackList.h"
+#include "mozilla/dom/HTMLCanvasElement.h"
 #include "MediaStreamGraph.h"
 #include "AudioStreamTrack.h"
 #include "VideoStreamTrack.h"
@@ -666,3 +667,4 @@ DOMAudioNodeMediaStream::CreateTrackUnionStream(nsIDOMWindow* aWindow,
   stream->InitTrackUnionStream(aWindow, aGraph);
   return stream.forget();
 }
+

dom/media/DOMMediaStream.h

@@ -36,6 +36,7 @@ class MediaStreamGraph;
 
 namespace dom {
 class AudioNode;
+class HTMLCanvasElement;
 class MediaStreamTrack;
 class AudioStreamTrack;
 class VideoStreamTrack;

dom/media/moz.build

@@ -175,6 +175,7 @@ EXPORTS.mozilla.dom += [
     'AudioStreamTrack.h',
     'AudioTrack.h',
     'AudioTrackList.h',
+    'CanvasCaptureMediaStream.h',
     'GetUserMediaRequest.h',
     'MediaDeviceInfo.h',
     'MediaDevices.h',
@@ -202,6 +203,7 @@ UNIFIED_SOURCES += [
     'AudioStreamTrack.cpp',
     'AudioTrack.cpp',
     'AudioTrackList.cpp',
+    'CanvasCaptureMediaStream.cpp',
     'CubebUtils.cpp',
     'DOMMediaStream.cpp',
     'EncodedBufferCache.cpp',

dom/tests/mochitest/general/test_interfaces.html

@@ -230,6 +230,8 @@ var interfaceNamesInGlobalScope =
     {name: "CameraRecorderVideoProfile", b2g: true},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "CameraStateChangeEvent", b2g: true},
+// IMPORTANT: Do not change this list without review from a DOM peer!
+    {name: "CanvasCaptureMediaStream", disabled: true},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "CanvasGradient",
 // IMPORTANT: Do not change this list without review from a DOM peer!

dom/webidl/CanvasCaptureMediaStream.webidl

@@ -0,0 +1,17 @@
+/* -*- Mode: IDL; 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/.
+ *
+ * The origin of this IDL file is
+ * https://w3c.github.io/mediacapture-fromelement/index.html
+ *
+ * Copyright © 2015 W3C® (MIT, ERCIM, Keio, Beihang), All Rights Reserved.
+ * W3C liability, trademark and document use rules apply.
+ */
+
+[Pref="canvas.capturestream.enabled"]
+interface CanvasCaptureMediaStream : MediaStream {
+    readonly attribute HTMLCanvasElement canvas;
+    void requestFrame();
+};

dom/webidl/HTMLCanvasElement.webidl

@@ -43,6 +43,9 @@ partial interface HTMLCanvasElement {
   [ChromeOnly]
   void mozFetchAsStream(nsIInputStreamCallback callback, optional DOMString? type = null);
            attribute PrintCallback? mozPrintCallback;
+
+  [Throws, UnsafeInPrerendering, Pref="canvas.capturestream.enabled"]
+  CanvasCaptureMediaStream captureStream(optional double frameRate);
 };
 
 [ChromeOnly]

dom/webidl/moz.build

@@ -65,6 +65,7 @@ WEBIDL_FILES = [
     'CameraControl.webidl',
     'CameraManager.webidl',
     'CameraUtil.webidl',
+    'CanvasCaptureMediaStream.webidl',
     'CanvasRenderingContext2D.webidl',
     'CaretPosition.webidl',
     'CDATASection.webidl',

modules/libpref/init/all.js

@@ -695,6 +695,8 @@ pref("canvas.hitregions.enabled", false);
 pref("canvas.filters.enabled", false);
 // Add support for canvas path objects
 pref("canvas.path.enabled", true);
+// captureStream() on canvas disabled by default
+pref("canvas.capturestream.enabled", false);
 
 // We want the ability to forcibly disable platform a11y, because
 // some non-a11y-related components attempt to bring it up.  See bug