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      1 /*
      2  * libjingle
      3  * Copyright 2015 Google Inc.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions are met:
      7  *
      8  *  1. Redistributions of source code must retain the above copyright notice,
      9  *     this list of conditions and the following disclaimer.
     10  *  2. Redistributions in binary form must reproduce the above copyright notice,
     11  *     this list of conditions and the following disclaimer in the documentation
     12  *     and/or other materials provided with the distribution.
     13  *  3. The name of the author may not be used to endorse or promote products
     14  *     derived from this software without specific prior written permission.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
     17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
     18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
     19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #include "talk/app/webrtc/mediastreamobserver.h"
     29 
     30 #include <algorithm>
     31 
     32 namespace webrtc {
     33 
     34 MediaStreamObserver::MediaStreamObserver(MediaStreamInterface* stream)
     35     : stream_(stream),
     36       cached_audio_tracks_(stream->GetAudioTracks()),
     37       cached_video_tracks_(stream->GetVideoTracks()) {
     38   stream_->RegisterObserver(this);
     39 }
     40 
     41 MediaStreamObserver::~MediaStreamObserver() {
     42   stream_->UnregisterObserver(this);
     43 }
     44 
     45 void MediaStreamObserver::OnChanged() {
     46   AudioTrackVector new_audio_tracks = stream_->GetAudioTracks();
     47   VideoTrackVector new_video_tracks = stream_->GetVideoTracks();
     48 
     49   // Find removed audio tracks.
     50   for (const auto& cached_track : cached_audio_tracks_) {
     51     auto it = std::find_if(
     52         new_audio_tracks.begin(), new_audio_tracks.end(),
     53         [cached_track](const AudioTrackVector::value_type& new_track) {
     54           return new_track->id().compare(cached_track->id()) == 0;
     55         });
     56     if (it == new_audio_tracks.end()) {
     57       SignalAudioTrackRemoved(cached_track.get(), stream_);
     58     }
     59   }
     60 
     61   // Find added audio tracks.
     62   for (const auto& new_track : new_audio_tracks) {
     63     auto it = std::find_if(
     64         cached_audio_tracks_.begin(), cached_audio_tracks_.end(),
     65         [new_track](const AudioTrackVector::value_type& cached_track) {
     66           return new_track->id().compare(cached_track->id()) == 0;
     67         });
     68     if (it == cached_audio_tracks_.end()) {
     69       SignalAudioTrackAdded(new_track.get(), stream_);
     70     }
     71   }
     72 
     73   // Find removed video tracks.
     74   for (const auto& cached_track : cached_video_tracks_) {
     75     auto it = std::find_if(
     76         new_video_tracks.begin(), new_video_tracks.end(),
     77         [cached_track](const VideoTrackVector::value_type& new_track) {
     78           return new_track->id().compare(cached_track->id()) == 0;
     79         });
     80     if (it == new_video_tracks.end()) {
     81       SignalVideoTrackRemoved(cached_track.get(), stream_);
     82     }
     83   }
     84 
     85   // Find added video tracks.
     86   for (const auto& new_track : new_video_tracks) {
     87     auto it = std::find_if(
     88         cached_video_tracks_.begin(), cached_video_tracks_.end(),
     89         [new_track](const VideoTrackVector::value_type& cached_track) {
     90           return new_track->id().compare(cached_track->id()) == 0;
     91         });
     92     if (it == cached_video_tracks_.end()) {
     93       SignalVideoTrackAdded(new_track.get(), stream_);
     94     }
     95   }
     96 
     97   cached_audio_tracks_ = new_audio_tracks;
     98   cached_video_tracks_ = new_video_tracks;
     99 }
    100 
    101 }  // namespace webrtc
    102