media/mojo/mojom/mirror_service_remoting.mojom

// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

module media.mojom;

import "media/mojo/mojom/remoting_common.mojom";

// Interface used by the source to start/stop remoting and send data to the
// sink.
interface MirrorServiceRemoter {
  // Starts a remoting session. Always assumes the remoting session will be
  // stared successfully. If any failure happens,
  // MirrorServiceRemotingSource::OnError() will be called.
  Start();

  // Starts remoting the media data streams. This is called after Start() to
  // indicate audio/video bitstream data is ready to be consumed. Returns
  // audio/video stream IDs. A valid stream ID should be greater than 0. When
  // there is no audio/video, or if the data stream is not successfully started,
  // the returned stream ID is -1.
  StartDataStreams(bool has_audio, bool has_video)
      => (int32 audio_stream_id, int32 video_stream_id);

  // Stops remoting media. Messages in both directions will be dropped after
  // this point as well as any pending or in-transit media bitstream data.
  Stop(RemotingStopReason reason);

  // Sends|message| to the sink. |message| is a serialized protobuf from
  // src/media/remoting/proto.
  SendMessageToSink(array<uint8> message);

  // Estimates the transmission capacity. Returns the result in
  // bytes per second.
  EstimateTransmissionCapacity() => (double rate);
};

// Interface used for sending notifications back to the source's control logic,
// and to pass messages from the sink back to the source.
interface MirrorServiceRemotingSource {
  // Notifies the source that the sink is now available to start remoting and
  // passes the receiver's metadata. It is up to the source's control logic
  // to decide whether/when to start remoting.
  OnSinkAvailable(RemotingSinkMetadata metadata);

  // Passes a |message| from the sink back to the source. The |message| consists
  // of a serialized protobuf from src/media/remoting/proto. This will only be
  // called after OnStarted() and before OnStopped().
  OnMessageFromSink(array<uint8> message);

  // Notifies the source that remoting has terminated. This may or may not be in
  // response to a MirrorServiceRemoter.Stop() call, as other events (possibly
  // external) may have caused remoting to end.
  OnStopped(RemotingStopReason reason);

  // Notifies the source that a fatal error has occurred. Remoting session will
  // be stopped immediately once this is called.
  // TODO(xjz): Add error codes in future to indicate different errors.
  OnError();
};