Attach TransportFeedbackPacketLossTracker to ANA (PLR only)

webrtc/modules/congestion_controller/transport_feedback_adapter.cc

 /*
  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 34 matching lines @@
     BitrateController* bitrate_controller)
     : send_side_bwe_with_overhead_(webrtc::field_trial::FindFullName(
           "WebRTC-SendSideBwe-WithOverhead") == "Enabled"),
       transport_overhead_bytes_per_packet_(0),
       send_time_history_(clock, kSendTimeHistoryWindowMs),
       clock_(clock),
       current_offset_ms_(kNoTimestamp),
       last_timestamp_us_(kNoTimestamp),
       bitrate_controller_(bitrate_controller) {}
 
-TransportFeedbackAdapter::~TransportFeedbackAdapter() {}
+TransportFeedbackAdapter::~TransportFeedbackAdapter() {
+  RTC_DCHECK(observers_.empty());
+}
 
 void TransportFeedbackAdapter::InitBwe() {
   rtc::CritScope cs(&bwe_lock_);
   delay_based_bwe_.reset(new DelayBasedBwe(clock_));
 }
 
-void TransportFeedbackAdapter::AddPacket(uint16_t sequence_number,
+void TransportFeedbackAdapter::AddPacket(uint32_t ssrc,
+                                         uint16_t sequence_number,
                                          size_t length,
                                          int probe_cluster_id) {
-  rtc::CritScope cs(&lock_);
-  if (send_side_bwe_with_overhead_) {
-    length += transport_overhead_bytes_per_packet_;
+  {
+    rtc::CritScope cs(&lock_);
+    if (send_side_bwe_with_overhead_) {
+      length += transport_overhead_bytes_per_packet_;
+    }
+    send_time_history_.AddAndRemoveOld(
+        sequence_number, length, probe_cluster_id);
   }
-  send_time_history_.AddAndRemoveOld(sequence_number, length, probe_cluster_id);
+
+  {
+    rtc::CritScope cs(&observers_lock_);
+    for (auto observer : observers_) {
+      observer->OnPacketAdded(ssrc, sequence_number);
+    }
+  }
 }
 
 void TransportFeedbackAdapter::OnSentPacket(uint16_t sequence_number,
                                             int64_t send_time_ms) {
   rtc::CritScope cs(&lock_);
   send_time_history_.OnSentPacket(sequence_number, send_time_ms);
 }
 
 void TransportFeedbackAdapter::SetStartBitrate(int start_bitrate_bps) {
   rtc::CritScope cs(&bwe_lock_);
   delay_based_bwe_->SetStartBitrate(start_bitrate_bps);
 }
 
 void TransportFeedbackAdapter::SetMinBitrate(int min_bitrate_bps) {
   rtc::CritScope cs(&bwe_lock_);
   delay_based_bwe_->SetMinBitrate(min_bitrate_bps);
 }
 
 void TransportFeedbackAdapter::SetTransportOverhead(
     int transport_overhead_bytes_per_packet) {
   rtc::CritScope cs(&lock_);
   transport_overhead_bytes_per_packet_ = transport_overhead_bytes_per_packet;
 }
 
 int64_t TransportFeedbackAdapter::GetProbingIntervalMs() const {
   rtc::CritScope cs(&bwe_lock_);
   return delay_based_bwe_->GetProbingIntervalMs();
 }
 
+void TransportFeedbackAdapter::RegisterTransportFeedbackAdapterObserver(
+    TransportFeedbackAdapterObserver* observer) {
+  rtc::CritScope cs(&observers_lock_);
+  RTC_DCHECK(observer);
+  if (std::find(observers_.begin(),

[minyue-webrtc, 2017/02/22 11:47:55]

I would the sanity check be debug only:

RTC_DCHECK_NE(observers_.end(), observers_.find(...))

[elad.alon_webrtc.org, 2017/03/10 12:03:26]

Are you sure? Observer registration is not an often-occurring event, so the
inefficiency of searching through the handful of observers seems worth the extra
safety we get here. Wdyt?

[minyue-webrtc, 2017/03/17 09:20:31]

My points are:
1. no user actions seem to trigger RegisterTransportFeedbackAdapterObserver, so
runtime check may not be needed.
2. if you think there is really a need to take care of re-registration, we don't
need the else part.

[elad.alon_webrtc.org, 2017/03/17 10:10:32]

The else-clause is there to alert a programmer running freshly modified code
that breaks this assumption (just like the RTC_DCHECK you suggest).
I'll change the code according to your suggestion, although my personal
preference is for the extra check.

[minyue-webrtc, 2017/03/21 09:22:58]

As a reader's point of view, I would like to see that you either forbid it or
allow misuse. It is a bit confusing if we say "we forbid it, but in case you
forget ..." That's why for my suggested code.

+                observers_.end(),
+                observer) == observers_.end()) {
+    observers_.push_back(observer);
+  } else {
+    RTC_NOTREACHED();
+  }
+}
+
+void TransportFeedbackAdapter::DeRegisterTransportFeedbackAdapterObserver(
+    TransportFeedbackAdapterObserver* observer) {
+  rtc::CritScope cs(&observers_lock_);
+  RTC_DCHECK(observer);
+  auto elem = std::find(observers_.begin(), observers_.end(), observer);
+  if (elem != observers_.end()) {
+    observers_.erase(elem);
+  } else {
+    RTC_NOTREACHED();
+  }
+}
+
 std::vector<PacketInfo> TransportFeedbackAdapter::GetPacketFeedbackVector(
     const rtcp::TransportFeedback& feedback) {
   int64_t timestamp_us = feedback.GetBaseTimeUs();
   // Add timestamp deltas to a local time base selected on first packet arrival.
   // This won't be the true time base, but makes it easier to manually inspect
   // time stamps.
   if (last_timestamp_us_ == kNoTimestamp) {
     current_offset_ms_ = clock_->TimeInMilliseconds();
   } else {
     int64_t delta = timestamp_us - last_timestamp_us_;
@@ skipping 40 matching lines @@
     const rtcp::TransportFeedback& feedback) {
   last_packet_feedback_vector_ = GetPacketFeedbackVector(feedback);
   DelayBasedBwe::Result result;
   {
     rtc::CritScope cs(&bwe_lock_);
     result = delay_based_bwe_->IncomingPacketFeedbackVector(
         last_packet_feedback_vector_);
   }
   if (result.updated)
     bitrate_controller_->OnDelayBasedBweResult(result);
+
+  {
+    rtc::CritScope cs(&observers_lock_);
+    for (auto observer : observers_) {
+      observer->OnTransportFeedback(feedback);
+    }
+  }
 }
 
 std::vector<PacketInfo> TransportFeedbackAdapter::GetTransportFeedbackVector()
     const {
   return last_packet_feedback_vector_;
 }
 
 void TransportFeedbackAdapter::OnRttUpdate(int64_t avg_rtt_ms,
                                            int64_t max_rtt_ms) {
   rtc::CritScope cs(&bwe_lock_);
   delay_based_bwe_->OnRttUpdate(avg_rtt_ms, max_rtt_ms);
 }
 
 }  // namespace webrtc