/* -*- 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 CAPTURETASK_H

#define CAPTURETASK_H

#include "MediaStreamGraph.h"

#include "MediaStreamListener.h"

#include "PrincipalChangeObserver.h"

#include "MediaStreamVideoSink.h"

namespace mozilla {

namespace dom {

class Blob;

class ImageCapture;

class MediaStreamTrack;

} // namespace dom

/**

 * CaptureTask retrieves image from MediaStream and encodes the image to jpeg in

 * ImageEncoder. The whole procedures start at AttachTrack(), it will add this

 * class into MediaStream and retrieves an image in MediaStreamGraph 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 MediaStreamVideoSink,

                    public dom::PrincipalChangeObserver<dom::MediaStreamTrack>

{

public:

  class MediaStreamEventListener;

  // MediaStreamVideoSink methods.

  void SetCurrentFrames(const VideoSegment& aSegment) override;

  void ClearFrames() override {}

  // PrincipalChangeObserver<MediaStreamTrack> method.

  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::Blob> aBlob, 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);

protected:

  virtual ~CaptureTask() {}

  // 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<MediaStreamEventListener> mEventListener;

  // True when an image is retrieved from MediaStreamGraph or MediaStreamGraph

  // sends a track finish, end, or removed event.

  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

#endif // CAPTURETASK_H