From 2001dc39db245973f757e1d5b389cf7ef9afe93e Mon Sep 17 00:00:00 2001
From: Tomas Gunnarsson <tommi@webrtc.org>
Date: Tue, 6 Apr 2021 11:36:00 +0200
Subject: [PATCH] Remove unnecessary thread hop for reporting transport stats

Bug: webrtc:12637
Change-Id: If00df716d30ac1db5faa83d2859f7c9787ad0ae9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/213662
Commit-Queue: Tommi <tommi@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33637}
---
 pc/peer_connection.cc | 42 ++++++++++++++++++++++--------------------
 pc/peer_connection.h  |  2 +-
 2 files changed, 23 insertions(+), 21 deletions(-)

diff --git a/pc/peer_connection.cc b/pc/peer_connection.cc
index 54713fef76..84803dafdb 100644
--- a/pc/peer_connection.cc
+++ b/pc/peer_connection.cc
@@ -675,6 +675,9 @@ void PeerConnection::InitializeTransportController_n(
   transport_controller_->SubscribeIceConnectionState(
       [this](cricket::IceConnectionState s) {
         RTC_DCHECK_RUN_ON(network_thread());
+        if (s == cricket::kIceConnectionConnected) {
+          ReportTransportStats();
+        }
         signaling_thread()->PostTask(
             ToQueuedTask(signaling_thread_safety_.flag(), [this, s]() {
               RTC_DCHECK_RUN_ON(signaling_thread());
@@ -2277,8 +2280,8 @@ void PeerConnection::OnTransportControllerConnectionState(
         SetIceConnectionState(PeerConnectionInterface::kIceConnectionConnected);
       }
       SetIceConnectionState(PeerConnectionInterface::kIceConnectionCompleted);
+
       NoteUsageEvent(UsageEvent::ICE_STATE_CONNECTED);
-      ReportTransportStats();
       break;
     default:
       RTC_NOTREACHED();
@@ -2638,6 +2641,7 @@ void PeerConnection::OnTransportControllerGatheringState(
   }
 }
 
+// Runs on network_thread().
 void PeerConnection::ReportTransportStats() {
   rtc::Thread::ScopedDisallowBlockingCalls no_blocking_calls;
   std::map<std::string, std::set<cricket::MediaType>>
@@ -2650,33 +2654,31 @@ void PeerConnection::ReportTransportStats() {
           transceiver->media_type());
     }
   }
+
   if (rtp_data_channel()) {
     media_types_by_transport_name[rtp_data_channel()->transport_name()].insert(
         cricket::MEDIA_TYPE_DATA);
   }
 
-  absl::optional<std::string> transport_name = sctp_transport_name();
-  if (transport_name) {
-    media_types_by_transport_name[*transport_name].insert(
-        cricket::MEDIA_TYPE_DATA);
+  if (sctp_mid_n_) {
+    auto dtls_transport = transport_controller_->GetDtlsTransport(*sctp_mid_n_);
+    if (dtls_transport) {
+      media_types_by_transport_name[dtls_transport->transport_name()].insert(
+          cricket::MEDIA_TYPE_DATA);
+    }
   }
 
-  // Run the loop that reports the state on the network thread since the
-  // transport controller requires the stats to be read there (GetStats()).
-  network_thread()->PostTask(ToQueuedTask(
-      network_thread_safety_, [this, media_types_by_transport_name = std::move(
-                                         media_types_by_transport_name)] {
-        for (const auto& entry : media_types_by_transport_name) {
-          const std::string& transport_name = entry.first;
-          const std::set<cricket::MediaType> media_types = entry.second;
-          cricket::TransportStats stats;
-          if (transport_controller_->GetStats(transport_name, &stats)) {
-            ReportBestConnectionState(stats);
-            ReportNegotiatedCiphers(dtls_enabled_, stats, media_types);
-          }
-        }
-      }));
+  for (const auto& entry : media_types_by_transport_name) {
+    const std::string& transport_name = entry.first;
+    const std::set<cricket::MediaType> media_types = entry.second;
+    cricket::TransportStats stats;
+    if (transport_controller_->GetStats(transport_name, &stats)) {
+      ReportBestConnectionState(stats);
+      ReportNegotiatedCiphers(dtls_enabled_, stats, media_types);
+    }
+  }
 }
+
 // Walk through the ConnectionInfos to gather best connection usage
 // for IPv4 and IPv6.
 // static (no member state required)
diff --git a/pc/peer_connection.h b/pc/peer_connection.h
index 34234244e8..bd2e80a47b 100644
--- a/pc/peer_connection.h
+++ b/pc/peer_connection.h
@@ -577,7 +577,7 @@ class PeerConnection : public PeerConnectionInternal,
 
   // Invoked when TransportController connection completion is signaled.
   // Reports stats for all transports in use.
-  void ReportTransportStats() RTC_RUN_ON(signaling_thread());
+  void ReportTransportStats() RTC_RUN_ON(network_thread());
 
   // Gather the usage of IPv4/IPv6 as best connection.
   static void ReportBestConnectionState(const cricket::TransportStats& stats);