1 /*
2 * Copyright 2015 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 #include "pc/media_stream_observer.h"
12
13 #include <string>
14 #include <vector>
15
16 #include "absl/algorithm/container.h"
17
18 namespace webrtc {
19
MediaStreamObserver(MediaStreamInterface * stream)20 MediaStreamObserver::MediaStreamObserver(MediaStreamInterface* stream)
21 : stream_(stream),
22 cached_audio_tracks_(stream->GetAudioTracks()),
23 cached_video_tracks_(stream->GetVideoTracks()) {
24 stream_->RegisterObserver(this);
25 }
26
~MediaStreamObserver()27 MediaStreamObserver::~MediaStreamObserver() {
28 stream_->UnregisterObserver(this);
29 }
30
OnChanged()31 void MediaStreamObserver::OnChanged() {
32 AudioTrackVector new_audio_tracks = stream_->GetAudioTracks();
33 VideoTrackVector new_video_tracks = stream_->GetVideoTracks();
34
35 // Find removed audio tracks.
36 for (const auto& cached_track : cached_audio_tracks_) {
37 if (absl::c_none_of(
38 new_audio_tracks,
39 [cached_track](const AudioTrackVector::value_type& new_track) {
40 return new_track->id() == cached_track->id();
41 })) {
42 SignalAudioTrackRemoved(cached_track.get(), stream_);
43 }
44 }
45
46 // Find added audio tracks.
47 for (const auto& new_track : new_audio_tracks) {
48 if (absl::c_none_of(
49 cached_audio_tracks_,
50 [new_track](const AudioTrackVector::value_type& cached_track) {
51 return new_track->id() == cached_track->id();
52 })) {
53 SignalAudioTrackAdded(new_track.get(), stream_);
54 }
55 }
56
57 // Find removed video tracks.
58 for (const auto& cached_track : cached_video_tracks_) {
59 if (absl::c_none_of(
60 new_video_tracks,
61 [cached_track](const VideoTrackVector::value_type& new_track) {
62 return new_track->id() == cached_track->id();
63 })) {
64 SignalVideoTrackRemoved(cached_track.get(), stream_);
65 }
66 }
67
68 // Find added video tracks.
69 for (const auto& new_track : new_video_tracks) {
70 if (absl::c_none_of(
71 cached_video_tracks_,
72 [new_track](const VideoTrackVector::value_type& cached_track) {
73 return new_track->id() == cached_track->id();
74 })) {
75 SignalVideoTrackAdded(new_track.get(), stream_);
76 }
77 }
78
79 cached_audio_tracks_ = new_audio_tracks;
80 cached_video_tracks_ = new_video_tracks;
81 }
82
83 } // namespace webrtc
84