Introduce RtpStreamReceiver and RtpStreamReceiverControllerInterface.

webrtc/call/flexfec_receive_stream_impl.cc

 /*
  *  Copyright (c) 2016 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.
  */
 
 #include "webrtc/call/flexfec_receive_stream_impl.h"
 
 #include <string>
 
 #include "webrtc/base/checks.h"
 #include "webrtc/base/location.h"
 #include "webrtc/base/logging.h"
+#include "webrtc/call/rtp_stream_receiver_controller_interface.h"
 #include "webrtc/modules/rtp_rtcp/include/flexfec_receiver.h"
 #include "webrtc/modules/rtp_rtcp/include/receive_statistics.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp.h"
 #include "webrtc/modules/rtp_rtcp/source/rtp_packet_received.h"
 #include "webrtc/modules/utility/include/process_thread.h"
 #include "webrtc/system_wrappers/include/clock.h"
 
 namespace webrtc {
 
 std::string FlexfecReceiveStream::Stats::ToString(int64_t time_ms) const {
@@ skipping 87 matching lines @@
   configuration.receive_statistics = receive_statistics;
   configuration.outgoing_transport = rtcp_send_transport;
   configuration.rtt_stats = rtt_stats;
   std::unique_ptr<RtpRtcp> rtp_rtcp(RtpRtcp::CreateRtpRtcp(configuration));
   return rtp_rtcp;
 }
 
 }  // namespace
 
 FlexfecReceiveStreamImpl::FlexfecReceiveStreamImpl(
+    RtpStreamReceiverControllerInterface* receiver_controller,
     const Config& config,
     RecoveredPacketReceiver* recovered_packet_receiver,
     RtcpRttStats* rtt_stats,
     ProcessThread* process_thread)
     : config_(config),
       started_(false),
       receiver_(MaybeCreateFlexfecReceiver(config_, recovered_packet_receiver)),
       rtp_receive_statistics_(
           ReceiveStatistics::Create(Clock::GetRealTimeClock())),
       rtp_rtcp_(CreateRtpRtcpModule(rtp_receive_statistics_.get(),
                                     config_.rtcp_send_transport,
                                     rtt_stats)),
       process_thread_(process_thread) {
   LOG(LS_INFO) << "FlexfecReceiveStreamImpl: " << config_.ToString();
 
   // RTCP reporting.
   rtp_rtcp_->SetRTCPStatus(config_.rtcp_mode);
   rtp_rtcp_->SetSSRC(config_.local_ssrc);
   process_thread_->RegisterModule(rtp_rtcp_.get(), RTC_FROM_HERE);
+
+  // Register with transport.
+  // TODO(nisse): OnRtpPacket in this class delegates all real work to
+  // |receiver_|. So maybe we don't need to implement RtpPacketSinkInterface
+  // here at all, we'd then delete the OnRtpPacket method and instead register
+  // |receiver_| as the RtpPacketSinkInterface for this stream.
+  // TODO(nisse): Passing |this| from the constructor to the RtpDemuxer, before
+  // the object is fully initialized, is risky. But it works in this case
+  // because locking in our caller, Call::CreateFlexfecReceiveStream, ensures
+  // that the demuxer doesn't call OnRtpPacket before this object is fully
+  // constructed. Registering |receiver_| instead of |this| would solve this
+  // problem too.
+  rtp_stream_receiver_ =
+      receiver_controller->CreateReceiver(config_.remote_ssrc, this);

[nisse-webrtc, 2017/06/20 13:35:35]

This is another case of passing |this| before the object is ready. For the time
being solved by protecting the construction by Call's |receive_crit_| lock.

I think the proper solution is to move statistics up a level or two, to
RtpReceiveStreamController/RtpTransportController, and then delete the
OnRtpPacket method of this class.

+  for (uint32_t ssrc : config.protected_media_ssrcs)
+    receiver_controller->AddSink(ssrc, this);
 }
 
 FlexfecReceiveStreamImpl::~FlexfecReceiveStreamImpl() {
   LOG(LS_INFO) << "~FlexfecReceiveStreamImpl: " << config_.ToString();
   Stop();
   process_thread_->DeRegisterModule(rtp_rtcp_.get());
 }
 
 void FlexfecReceiveStreamImpl::OnRtpPacket(const RtpPacketReceived& packet) {
   {
@@ skipping 28 matching lines @@
   started_ = false;
 }
 
 // TODO(brandtr): Implement this member function when we have designed the
 // stats for FlexFEC.
 FlexfecReceiveStreamImpl::Stats FlexfecReceiveStreamImpl::GetStats() const {
   return FlexfecReceiveStream::Stats();
 }
 
 }  // namespace webrtc