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/* -*- 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 */
#include "MediaTrackGraph.h"
#include "MediaTrackListener.h"
#include "PrincipalChangeObserver.h"
namespace mozilla {
namespace dom {
class BlobImpl;
class ImageCapture;
class MediaStreamTrack;
} // namespace dom
* CaptureTask retrieves image from MediaTrack and encodes the image to jpeg in
* ImageEncoder. The whole procedures start at AttachTrack(), it will add this
* class into MediaTrack and retrieves an image in MediaTrackGraph thread.
* Once the image is retrieved, it will be sent to ImageEncoder and the encoded
* blob will be sent out via encoder callback in main thread.
* CaptureTask holds a reference of ImageCapture to ensure ImageCapture won't be
* released during the period of the capturing process described above.
class CaptureTask : public DirectMediaTrackListener,
public dom::PrincipalChangeObserver<dom::MediaStreamTrack> {
class MediaTrackEventListener;
// DirectMediaTrackListener methods
void NotifyRealtimeTrackData(MediaTrackGraph* aGraph, TrackTime aTrackOffset,
const MediaSegment& aMedia) override;
// PrincipalChangeObserver<MediaStreamTrack> methods
void PrincipalChanged(dom::MediaStreamTrack* aMediaStreamTrack) override;
// CaptureTask methods.
// It is called when aBlob is ready to post back to script in company with
// aRv == NS_OK. If aRv is not NS_OK, it will post an error event to script.
// Note:
// this function should be called on main thread.
nsresult TaskComplete(already_AddRefed<dom::BlobImpl> aBlobImpl,
nsresult aRv);
// Add listeners into MediaStreamTrack and PrincipalChangeObserver.
// It should be on main thread only.
void AttachTrack();
// Remove listeners from MediaStreamTrack and PrincipalChangeObserver.
// It should be on main thread only.
void DetachTrack();
// CaptureTask should be created on main thread.
explicit CaptureTask(dom::ImageCapture* aImageCapture);
virtual ~CaptureTask() = default;
// Post a runnable on main thread to end this task and call TaskComplete to
// post error event to script. It is called off-main-thread.
void PostTrackEndEvent();
// The ImageCapture associates with this task. This reference count should not
// change in this class unless it clears this reference after a blob or error
// event to script.
RefPtr<dom::ImageCapture> mImageCapture;
RefPtr<MediaTrackEventListener> mEventListener;
// True when an image is retrieved from the video track, or MediaTrackGraph
// sends a track finish, end, or removed event. Any thread.
Atomic<bool> mImageGrabbedOrTrackEnd;
// True after MediaStreamTrack principal changes while waiting for a photo
// to finish and we should raise a security error.
bool mPrincipalChanged;
} // namespace mozilla