commit 0f0bcb39f3fcb2b6185f146dfc4f4357276e40d4
author Harald Alvestrand <hta@webrtc.org> Mon Dec 07 11:45:55 2020
committer Commit Bot <commit-bot@chromium.org> Mon Dec 07 13:27:54 2020
tree 44b5775da005d5d177adb679fbbbe04529fdd01f
parent ea969d287bfe6634c8925f34f9e7997d168dfca1

Declare BaseChannel::media_channel_ const

This makes it thread-safe to access, but not necessarily to use.

Bug: webrtc:12230
Change-Id: I6b48d86dff24b162d382135abeaf560971fdf614
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/196524
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32785}

pc/channel.cc

diff --git a/pc/channel.cc b/pc/channel.cc
index 6ab4371..aad7c54 100644
--- a/pc/channel.cc
+++ b/pc/channel.cc
@@ -152,17 +152,12 @@
   // Eats any outstanding messages or packets.
   worker_thread_->Clear(&invoker_);
   worker_thread_->Clear(this);
-  // We must destroy the media channel before the transport channel, otherwise
-  // the media channel may try to send on the dead transport channel. NULLing
-  // is not an effective strategy since the sends will come on another thread.
-  media_channel_.reset();
-  RTC_LOG(LS_INFO) << "Destroyed channel: " << ToString();
+  // The media channel is destroyed at the end of the destructor, since it
+  // is a std::unique_ptr. The transport channel (rtp_transport) must outlive
+  // the media channel.
 }
 
 std::string BaseChannel::ToString() const {
-  // TODO(bugs.webrtc.org/12230): When media_channel_ is guarded by
-  // worker_thread(), rewrite this debug printout to not print the
-  // media type when called from non-worker-thread.
   rtc::StringBuilder sb;
   sb << "{mid: " << content_name_;
   if (media_channel_) {

pc/channel.h

diff --git a/pc/channel.h b/pc/channel.h
index ad75070..d9e6d9b 100644
--- a/pc/channel.h
+++ b/pc/channel.h
@@ -185,9 +185,6 @@
   }
 
   MediaChannel* media_channel() const override {
-    // TODO(bugs.webrtc.org/12230): Called on multiple threads,
-    // including from StatsCollector::ExtractMediaInfo.
-    // RTC_DCHECK_RUN_ON(worker_thread());
     return media_channel_.get();
   }
 
@@ -348,9 +345,7 @@
 
   // MediaChannel related members that should be accessed from the worker
   // thread.
-  // TODO(bugs.webrtc.org/12230): written on worker thread, accessed by
-  // multiple threads.
-  std::unique_ptr<MediaChannel> media_channel_;
+  const std::unique_ptr<MediaChannel> media_channel_;
   // Currently the |enabled_| flag is accessed from the signaling thread as
   // well, but it can be changed only when signaling thread does a synchronous
   // call to the worker thread, so it should be safe.