fix: datachannel deadlocks & dispose crashes (#87)

- Fix datachannel deadlock on dispose
- Fix audio device being disposed on the wrong thread
- Allow multiple RtcRuntime to be created (Useful for unit tests where we use multiple PeerConnectionFactory)

livekit-webrtc/src/peer_connection.rs

@@ -247,13 +247,9 @@ mod tests {
     use log::trace;
     use tokio::sync::mpsc;
 
-    fn init_log() {
-        let _ = env_logger::builder().is_test(true).try_init();
-    }
-
     #[tokio::test]
     async fn create_pc() {
-        init_log();
+        let _ = env_logger::builder().is_test(true).try_init();
 
         let factory = PeerConnectionFactory::default();
         let config = RtcConfiguration {
@@ -269,20 +265,20 @@ mod tests {
         let bob = factory.create_peer_connection(config.clone()).unwrap();
         let alice = factory.create_peer_connection(config.clone()).unwrap();
 
-        let (bob_ice_tx, mut bob_ice_rx) = mpsc::channel::<IceCandidate>(16);
-        let (alice_ice_tx, mut alice_ice_rx) = mpsc::channel::<IceCandidate>(16);
-        let (alice_dc_tx, mut alice_dc_rx) = mpsc::channel::<DataChannel>(16);
+        let (bob_ice_tx, mut bob_ice_rx) = mpsc::unbounded_channel::<IceCandidate>();
+        let (alice_ice_tx, mut alice_ice_rx) = mpsc::unbounded_channel::<IceCandidate>();
+        let (alice_dc_tx, mut alice_dc_rx) = mpsc::unbounded_channel::<DataChannel>();
 
         bob.on_ice_candidate(Some(Box::new(move |candidate| {
-            bob_ice_tx.blocking_send(candidate).unwrap();
+            bob_ice_tx.send(candidate).unwrap();
         })));
 
         alice.on_ice_candidate(Some(Box::new(move |candidate| {
-            alice_ice_tx.blocking_send(candidate).unwrap();
+            alice_ice_tx.send(candidate).unwrap();
         })));
 
         alice.on_data_channel(Some(Box::new(move |dc| {
-            alice_dc_tx.blocking_send(dc).unwrap();
+            alice_dc_tx.send(dc).unwrap();
         })));
 
         let bob_dc = bob
@@ -305,11 +301,11 @@ mod tests {
         bob.add_ice_candidate(alice_ice).await.unwrap();
         alice.add_ice_candidate(bob_ice).await.unwrap();
 
-        let (data_tx, mut data_rx) = mpsc::channel::<String>(1);
+        let (data_tx, mut data_rx) = mpsc::unbounded_channel::<String>();
         let alice_dc = alice_dc_rx.recv().await.unwrap();
         alice_dc.on_message(Some(Box::new(move |buffer| {
             data_tx
-                .blocking_send(String::from_utf8_lossy(buffer.data).to_string())
+                .send(String::from_utf8_lossy(buffer.data).to_string())
                 .unwrap();
         })));
 

webrtc-sys/include/livekit/data_channel.h

@@ -40,6 +40,7 @@ class DataChannel {
   explicit DataChannel(
       std::shared_ptr<RtcRuntime> rtc_runtime,
       rtc::scoped_refptr<webrtc::DataChannelInterface> data_channel);
+  ~DataChannel();
 
   void register_observer(rust::Box<DataChannelObserverWrapper> observer) const;
   void unregister_observer() const;
@@ -64,8 +65,6 @@ class NativeDataChannelObserver : public webrtc::DataChannelObserver {
   NativeDataChannelObserver(rust::Box<DataChannelObserverWrapper> observer,
                             const DataChannel* dc);
 
-  ~NativeDataChannelObserver();
-
   void OnStateChange() override;
   void OnMessage(const webrtc::DataBuffer& buffer) override;
   void OnBufferedAmountChange(uint64_t sent_data_size) override;

webrtc-sys/include/livekit/peer_connection.h

@@ -48,6 +48,8 @@ class PeerConnection {
       std::unique_ptr<NativePeerConnectionObserver> observer,
       rtc::scoped_refptr<webrtc::PeerConnectionInterface> peer_connection);
 
+  ~PeerConnection();
+
   void create_offer(
       RtcOfferAnswerOptions options,
       rust::Box<AsyncContext> ctx,

webrtc-sys/include/livekit/peer_connection_factory.h

@@ -17,6 +17,8 @@
 #pragma once
 
 #include "api/peer_connection_interface.h"
+#include "api/scoped_refptr.h"
+#include "livekit/audio_device.h"
 #include "media_stream.h"
 #include "peer_connection.h"
 #include "rtp_parameters.h"
@@ -57,6 +59,7 @@ class PeerConnectionFactory {
 
  private:
   std::shared_ptr<RtcRuntime> rtc_runtime_;
+  rtc::scoped_refptr<AudioDevice> audio_device_;
   rtc::scoped_refptr<webrtc::PeerConnectionFactoryInterface> peer_factory_;
 };
 

webrtc-sys/include/livekit/webrtc.h

@@ -80,6 +80,8 @@ class RtcRuntime : public std::enable_shared_from_this<RtcRuntime> {
   // have one livekit::VideoTrack associated with it).
   // The only reason we to do that is to allow to add states inside our
   // wrappers (e.g: the sinks_ member inside AudioTrack)
+  // DataChannel and the PeerConnectionFactory don't need to do this (There's no
+  // way to retrieve them after creation)
   webrtc::Mutex mutex_;
   std::vector<std::weak_ptr<MediaStreamTrack>> media_stream_tracks_;
   // We don't have additonal state in RtpReceiver and RtpSender atm..
@@ -87,9 +89,9 @@ class RtcRuntime : public std::enable_shared_from_this<RtcRuntime> {
   // std::vector<std::weak_ptr<RtpSender>> rtp_senders_;
 
 #ifdef WEBRTC_WIN
-  rtc::WinsockInitializer winsock_;
-  rtc::PhysicalSocketServer ss_;
-  rtc::AutoSocketServerThread main_thread_{&ss_};
+  // rtc::WinsockInitializer winsock_;
+  // rtc::PhysicalSocketServer ss_;
+  // rtc::AutoSocketServerThread main_thread_{&ss_};
 #endif
 };
 

webrtc-sys/src/data_channel.cpp

@@ -47,6 +47,10 @@ DataChannel::DataChannel(
     rtc::scoped_refptr<webrtc::DataChannelInterface> data_channel)
     : rtc_runtime_(rtc_runtime), data_channel_(std::move(data_channel)) {}
 
+DataChannel::~DataChannel() {
+  unregister_observer();
+}
+
 void DataChannel::register_observer(
     rust::Box<DataChannelObserverWrapper> observer) const {
   webrtc::MutexLock lock(&mutex_);
@@ -86,10 +90,6 @@ NativeDataChannelObserver::NativeDataChannelObserver(
     const DataChannel* dc)
     : observer_(std::move(observer)), dc_(dc) {}
 
-NativeDataChannelObserver::~NativeDataChannelObserver() {
-  dc_->unregister_observer();
-}
-
 void NativeDataChannelObserver::OnStateChange() {
   observer_->on_state_change(dc_->state());
 }

webrtc-sys/src/peer_connection.cpp

@@ -25,6 +25,7 @@
 #include "livekit/media_stream.h"
 #include "livekit/rtc_error.h"
 #include "livekit/rtp_transceiver.h"
+#include "rtc_base/logging.h"
 #include "webrtc-sys/src/peer_connection.rs.h"
 #include "webrtc-sys/src/rtc_error.rs.h"
 
@@ -50,7 +51,13 @@ PeerConnection::PeerConnection(
     rtc::scoped_refptr<webrtc::PeerConnectionInterface> peer_connection)
     : rtc_runtime_(rtc_runtime),
       observer_(std::move(observer)),
-      peer_connection_(std::move(peer_connection)) {}
+      peer_connection_(std::move(peer_connection)) {
+  RTC_LOG(LS_VERBOSE) << "PeerConnection::PeerConnection()";
+}
+
+PeerConnection::~PeerConnection() {
+  RTC_LOG(LS_VERBOSE) << "PeerConnection::~PeerConnection()";
+}
 
 void PeerConnection::create_offer(
     RtcOfferAnswerOptions options,

webrtc-sys/src/peer_connection_factory.cpp

@@ -70,7 +70,7 @@ webrtc::PeerConnectionInterface::RTCConfiguration to_native_rtc_configuration(
 PeerConnectionFactory::PeerConnectionFactory(
     std::shared_ptr<RtcRuntime> rtc_runtime)
     : rtc_runtime_(rtc_runtime) {
-  RTC_LOG(LS_INFO) << "PeerConnectionFactory::PeerConnectionFactory()";
+  RTC_LOG(LS_VERBOSE) << "PeerConnectionFactory::PeerConnectionFactory()";
 
   webrtc::PeerConnectionFactoryDependencies dependencies;
   dependencies.network_thread = rtc_runtime_->network_thread();
@@ -86,12 +86,14 @@ PeerConnectionFactory::PeerConnectionFactory(
   cricket::MediaEngineDependencies media_deps;
   media_deps.task_queue_factory = dependencies.task_queue_factory.get();
 
-  media_deps.adm = rtc_runtime_->worker_thread()
-                       ->Invoke<rtc::scoped_refptr<livekit::AudioDevice>>(
-                           RTC_FROM_HERE, [&] {
-                             return rtc::make_ref_counted<livekit::AudioDevice>(
-                                 media_deps.task_queue_factory);
-                           });
+  audio_device_ = rtc_runtime_->worker_thread()
+                      ->Invoke<rtc::scoped_refptr<livekit::AudioDevice>>(
+                          RTC_FROM_HERE, [&] {
+                            return rtc::make_ref_counted<livekit::AudioDevice>(
+                                media_deps.task_queue_factory);
+                          });
+
+  media_deps.adm = audio_device_;
 
   media_deps.video_encoder_factory =
       std::move(std::make_unique<livekit::VideoEncoderFactory>());
@@ -114,7 +116,11 @@ PeerConnectionFactory::PeerConnectionFactory(
 }
 
 PeerConnectionFactory::~PeerConnectionFactory() {
-  RTC_LOG(LS_INFO) << "PeerConnectionFactory::~PeerConnectionFactory()";
+  RTC_LOG(LS_VERBOSE) << "PeerConnectionFactory::~PeerConnectionFactory()";
+
+  peer_factory_ = nullptr;
+  rtc_runtime_->worker_thread()->Invoke<void>(
+      RTC_FROM_HERE, [this] { audio_device_ = nullptr; });
 }
 
 std::shared_ptr<PeerConnection> PeerConnectionFactory::create_peer_connection(

webrtc-sys/src/webrtc.cpp

@@ -16,6 +16,9 @@
 
 #include "livekit/webrtc.h"
 
+#include <algorithm>
+#include <atomic>
+#include <iostream>
 #include <memory>
 
 #include "livekit/audio_track.h"
@@ -27,10 +30,34 @@
 #include "rtc_base/logging.h"
 #include "rtc_base/synchronization/mutex.h"
 
+#ifdef WEBRTC_WIN
+#include "rtc_base/win32.h"
+#endif
+
 namespace livekit {
+
+static webrtc::Mutex g_mutex{};
+// Can't be atomic, we're using a Mutex because we need to wait for the
+// execution of the first init
+static uint32_t g_release_counter(0);
+
 RtcRuntime::RtcRuntime() {
-  RTC_LOG(LS_INFO) << "RtcRuntime()";
-  RTC_CHECK(rtc::InitializeSSL()) << "Failed to InitializeSSL()";
+  rtc::LogMessage::LogToDebug(rtc::LS_INFO);
+  RTC_LOG(LS_VERBOSE) << "RtcRuntime()";
+
+  {
+    // Not the best way to do it...
+    webrtc::MutexLock lock(&g_mutex);
+    if (g_release_counter == 0) {
+      RTC_CHECK(rtc::InitializeSSL()) << "Failed to InitializeSSL()";
+
+#ifdef WEBRTC_WIN
+      WSADATA data;
+      WSAStartup(MAKEWORD(1, 0), &data);
+#endif
+    }
+    g_release_counter++;
+  }
 
   network_thread_ = rtc::Thread::CreateWithSocketServer();
   network_thread_->SetName("network_thread", &network_thread_);
@@ -44,14 +71,23 @@ RtcRuntime::RtcRuntime() {
 }
 
 RtcRuntime::~RtcRuntime() {
-  RTC_LOG(LS_INFO) << "~RtcRuntime()";
+  RTC_LOG(LS_VERBOSE) << "~RtcRuntime()";
 
-  rtc::ThreadManager::Instance()->SetCurrentThread(nullptr);
-  RTC_CHECK(rtc::CleanupSSL()) << "Failed to CleanupSSL()";
+  worker_thread_->Stop();
+  signaling_thread_->Stop();
+  network_thread_->Stop();
 
-  worker_thread_->Quit();
-  signaling_thread_->Quit();
-  network_thread_->Quit();
+  {
+    webrtc::MutexLock lock(&g_mutex);
+    g_release_counter--;
+    if (g_release_counter == 0) {
+      RTC_CHECK(rtc::CleanupSSL()) << "Failed to CleanupSSL()";
+
+#ifdef WEBRTC_WIN
+      WSACleanup();
+#endif
+    }
+  }
 }
 
 rtc::Thread* RtcRuntime::network_thread() const {