commit 8546666cb9db79a39ddded7048bb5f82e9f4af87
author Harald Alvestrand <hta@webrtc.org> Mon Apr 19 21:21:36 2021
committer Commit Bot <commit-bot@chromium.org> Tue Apr 20 06:44:40 2021
tree a9e4f786bd871809566f65e697fa6c26211f82e0
parent dcac9fe3d1646465e6dbc2c6bf1d465e79ba5414

Add threading assertions to TransceiverList

Also add a function for accessing the list as internal transceivers
rather than accessing the proxy objects; this exposes where the
internal objects are accessed and where we need external references.

Used the new list function in sdp_offer_answer wherever possible.

Adds an UnsafeList function that is not thread guarded, so that the
job of rooting out those instances can be done in a later CL.

Bug: webrtc:12692
Change-Id: Ia591f22a1c8f82ec452a1a66a94fbf9ab9debd14
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/215581
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33781}

pc/transceiver_list.cc

diff --git a/pc/transceiver_list.cc b/pc/transceiver_list.cc
index 63d3e67..235c9af 100644
--- a/pc/transceiver_list.cc
+++ b/pc/transceiver_list.cc
@@ -41,8 +41,18 @@
   init_send_encodings_ = encodings;
 }
 
+std::vector<RtpTransceiver*> TransceiverList::ListInternal() const {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  std::vector<RtpTransceiver*> internals;
+  for (auto transceiver : transceivers_) {
+    internals.push_back(transceiver->internal());
+  }
+  return internals;
+}
+
 RtpTransceiverProxyRefPtr TransceiverList::FindBySender(
     rtc::scoped_refptr<RtpSenderInterface> sender) const {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
   for (auto transceiver : transceivers_) {
     if (transceiver->sender() == sender) {
       return transceiver;
@@ -53,6 +63,7 @@
 
 RtpTransceiverProxyRefPtr TransceiverList::FindByMid(
     const std::string& mid) const {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
   for (auto transceiver : transceivers_) {
     if (transceiver->mid() == mid) {
       return transceiver;
@@ -63,6 +74,7 @@
 
 RtpTransceiverProxyRefPtr TransceiverList::FindByMLineIndex(
     size_t mline_index) const {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
   for (auto transceiver : transceivers_) {
     if (transceiver->internal()->mline_index() == mline_index) {
       return transceiver;