Use separate rtp module lists for send and receive in PacketRouter.

webrtc/modules/pacing/packet_router.cc

Index: webrtc/modules/pacing/packet_router.cc
diff --git a/webrtc/modules/pacing/packet_router.cc b/webrtc/modules/pacing/packet_router.cc
index 5fd350834a5e1ec6231966d0e7e207f79b5e5b99..e98ab0c2b02539963758ce0259c412e5657f385f 100644
--- a/webrtc/modules/pacing/packet_router.cc
+++ b/webrtc/modules/pacing/packet_router.cc
@@ -18,33 +18,64 @@
 
 namespace webrtc {
 
+namespace {
+void AddModule(RtpRtcp* rtp_module, std::list<RtpRtcp*>* rtp_modules) {
+  RTC_DCHECK(std::find(rtp_modules->begin(), rtp_modules->end(), rtp_module) ==
+             rtp_modules->end());
+  rtp_modules->push_back(rtp_module);
+}
+
+void RemoveModule(RtpRtcp* rtp_module, std::list<RtpRtcp*>* rtp_modules) {
+  RTC_DCHECK(std::find(rtp_modules->begin(), rtp_modules->end(), rtp_module) !=
+             rtp_modules->end());
+  rtp_modules->remove(rtp_module);
+}
+
+bool SendFeedback(rtcp::TransportFeedback* packet,
+                  std::list<RtpRtcp*>* rtp_modules) {
+  for (auto* rtp_module : *rtp_modules) {
+    packet->WithPacketSenderSsrc(rtp_module->SSRC());
+    if (rtp_module->SendFeedbackPacket(*packet))
+      return true;
+  }
+  return false;
+}
+}
+
 PacketRouter::PacketRouter() : transport_seq_(0) {
+  pacer_thread_checker_.DetachFromThread();
 }
 
 PacketRouter::~PacketRouter() {
-  RTC_DCHECK(rtp_modules_.empty());
+  RTC_DCHECK(send_rtp_modules_.empty());
+  RTC_DCHECK(recv_rtp_modules_.empty());
 }
 
-void PacketRouter::AddRtpModule(RtpRtcp* rtp_module) {
-  rtc::CritScope cs(&modules_lock_);
-  RTC_DCHECK(std::find(rtp_modules_.begin(), rtp_modules_.end(), rtp_module) ==
-             rtp_modules_.end());
-  rtp_modules_.push_back(rtp_module);
+void PacketRouter::AddRtpModule(RtpRtcp* rtp_module, bool sender) {
+  rtc::CritScope cs(&modules_crit_);
+  if (sender) {
+    AddModule(rtp_module, &send_rtp_modules_);
+  } else {
+    AddModule(rtp_module, &recv_rtp_modules_);
+  }
 }
 
-void PacketRouter::RemoveRtpModule(RtpRtcp* rtp_module) {
-  rtc::CritScope cs(&modules_lock_);
-  auto it = std::find(rtp_modules_.begin(), rtp_modules_.end(), rtp_module);
-  RTC_DCHECK(it != rtp_modules_.end());
-  rtp_modules_.erase(it);
+void PacketRouter::RemoveRtpModule(RtpRtcp* rtp_module, bool sender) {
+  rtc::CritScope cs(&modules_crit_);
+  if (sender) {
+    RemoveModule(rtp_module, &send_rtp_modules_);
+  } else {
+    RemoveModule(rtp_module, &recv_rtp_modules_);
+  }
 }
 
 bool PacketRouter::TimeToSendPacket(uint32_t ssrc,
                                     uint16_t sequence_number,
                                     int64_t capture_timestamp,
                                     bool retransmission) {
-  rtc::CritScope cs(&modules_lock_);
-  for (auto* rtp_module : rtp_modules_) {
+  RTC_DCHECK(pacer_thread_checker_.CalledOnValidThread());
+  rtc::CritScope cs(&modules_crit_);
+  for (auto* rtp_module : send_rtp_modules_) {
     if (rtp_module->SendingMedia() && ssrc == rtp_module->SSRC()) {
       return rtp_module->TimeToSendPacket(ssrc, sequence_number,
                                           capture_timestamp, retransmission);
@@ -54,9 +85,10 @@ bool PacketRouter::TimeToSendPacket(uint32_t ssrc,
 }
 
 size_t PacketRouter::TimeToSendPadding(size_t bytes_to_send) {
+  RTC_DCHECK(pacer_thread_checker_.CalledOnValidThread());
   size_t total_bytes_sent = 0;
-  rtc::CritScope cs(&modules_lock_);
-  for (RtpRtcp* module : rtp_modules_) {
+  rtc::CritScope cs(&modules_crit_);
+  for (RtpRtcp* module : send_rtp_modules_) {
     if (module->SendingMedia()) {
       size_t bytes_sent =
           module->TimeToSendPadding(bytes_to_send - total_bytes_sent);
@@ -91,12 +123,12 @@ uint16_t PacketRouter::AllocateSequenceNumber() {
 }
 
 bool PacketRouter::SendFeedback(rtcp::TransportFeedback* packet) {
-  rtc::CritScope cs(&modules_lock_);
-  for (auto* rtp_module : rtp_modules_) {
-    packet->WithPacketSenderSsrc(rtp_module->SSRC());
-    if (rtp_module->SendFeedbackPacket(*packet))
-      return true;
-  }
+  RTC_DCHECK(pacer_thread_checker_.CalledOnValidThread());
+  rtc::CritScope cs(&modules_crit_);
+  if (::webrtc::SendFeedback(packet, &recv_rtp_modules_))
+    return true;
+  if (::webrtc::SendFeedback(packet, &send_rtp_modules_))
+    return true;
   return false;
 }