PlatformThread: add support for detached threads.

The change introduces support for detachable PlatformThreads, for which
the Stop() call doesn't wait until the thread has finished executing.

The change also introduces rtc::ThreadAttributes that carries priority
and detachability thread attributes. It additionally refactors all
known use to use the new semantics.

Bug: b:181572711, webrtc:12659
Change-Id: Id96e87c2a0dafabc8047767d241fd5da4505d14c
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/214704
Reviewed-by: Tommi <tommi@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: Markus Handell <handellm@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#33796}

modules/audio_coding/acm2/audio_coding_module_unittest.cc

@@ -429,15 +429,21 @@ class AudioCodingModuleMtTestOldApi : public AudioCodingModuleTestOldApi {
 
   AudioCodingModuleMtTestOldApi()
       : AudioCodingModuleTestOldApi(),
-        send_thread_(CbSendThread, this, "send", rtc::kRealtimePriority),
-        insert_packet_thread_(CbInsertPacketThread,
-                              this,
-                              "insert_packet",
-                              rtc::kRealtimePriority),
-        pull_audio_thread_(CbPullAudioThread,
-                           this,
-                           "pull_audio",
-                           rtc::kRealtimePriority),
+        send_thread_(
+            CbSendThread,
+            this,
+            "send",
+            rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)),
+        insert_packet_thread_(
+            CbInsertPacketThread,
+            this,
+            "insert_packet",
+            rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)),
+        pull_audio_thread_(
+            CbPullAudioThread,
+            this,
+            "pull_audio",
+            rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)),
         send_count_(0),
         insert_packet_count_(0),
         pull_audio_count_(0),
@@ -693,14 +699,16 @@ class AcmReRegisterIsacMtTestOldApi : public AudioCodingModuleTestOldApi {
 
   AcmReRegisterIsacMtTestOldApi()
       : AudioCodingModuleTestOldApi(),
-        receive_thread_(CbReceiveThread,
-                        this,
-                        "receive",
-                        rtc::kRealtimePriority),
-        codec_registration_thread_(CbCodecRegistrationThread,
-                                   this,
-                                   "codec_registration",
-                                   rtc::kRealtimePriority),
+        receive_thread_(
+            CbReceiveThread,
+            this,
+            "receive",
+            rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)),
+        codec_registration_thread_(
+            CbCodecRegistrationThread,
+            this,
+            "codec_registration",
+            rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)),
         codec_registered_(false),
         receive_packet_count_(0),
         next_insert_packet_time_ms_(0),

modules/audio_device/dummy/file_audio_device.cc

@@ -218,7 +218,7 @@ int32_t FileAudioDevice::StartPlayout() {
 
   _ptrThreadPlay.reset(new rtc::PlatformThread(
       PlayThreadFunc, this, "webrtc_audio_module_play_thread",
-      rtc::kRealtimePriority));
+      rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)));
   _ptrThreadPlay->Start();
 
   RTC_LOG(LS_INFO) << "Started playout capture to output file: "
@@ -278,7 +278,7 @@ int32_t FileAudioDevice::StartRecording() {
 
   _ptrThreadRec.reset(new rtc::PlatformThread(
       RecThreadFunc, this, "webrtc_audio_module_capture_thread",
-      rtc::kRealtimePriority));
+      rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)));
 
   _ptrThreadRec->Start();
 

modules/audio_device/linux/audio_device_alsa_linux.cc

@@ -1042,7 +1042,7 @@ int32_t AudioDeviceLinuxALSA::StartRecording() {
   // RECORDING
   _ptrThreadRec.reset(new rtc::PlatformThread(
       RecThreadFunc, this, "webrtc_audio_module_capture_thread",
-      rtc::kRealtimePriority));
+      rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)));
 
   _ptrThreadRec->Start();
 
@@ -1160,7 +1160,7 @@ int32_t AudioDeviceLinuxALSA::StartPlayout() {
   // PLAYOUT
   _ptrThreadPlay.reset(new rtc::PlatformThread(
       PlayThreadFunc, this, "webrtc_audio_module_play_thread",
-      rtc::kRealtimePriority));
+      rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)));
   _ptrThreadPlay->Start();
 
   int errVal = LATE(snd_pcm_prepare)(_handlePlayout);

modules/audio_device/linux/audio_device_pulse_linux.cc

@@ -158,16 +158,16 @@ AudioDeviceGeneric::InitStatus AudioDeviceLinuxPulse::Init() {
 #endif
 
   // RECORDING
-  _ptrThreadRec.reset(new rtc::PlatformThread(RecThreadFunc, this,
-                                              "webrtc_audio_module_rec_thread",
-                                              rtc::kRealtimePriority));
+  _ptrThreadRec.reset(new rtc::PlatformThread(
+      RecThreadFunc, this, "webrtc_audio_module_rec_thread",
+      rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)));
 
   _ptrThreadRec->Start();
 
   // PLAYOUT
   _ptrThreadPlay.reset(new rtc::PlatformThread(
       PlayThreadFunc, this, "webrtc_audio_module_play_thread",
-      rtc::kRealtimePriority));
+      rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)));
   _ptrThreadPlay->Start();
 
   _initialized = true;

modules/audio_device/mac/audio_device_mac.cc

@@ -1310,7 +1310,8 @@ int32_t AudioDeviceMac::StartRecording() {
 
   RTC_DCHECK(!capture_worker_thread_.get());
   capture_worker_thread_.reset(new rtc::PlatformThread(
-      RunCapture, this, "CaptureWorkerThread", rtc::kRealtimePriority));
+      RunCapture, this, "CaptureWorkerThread",
+      rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)));
   RTC_DCHECK(capture_worker_thread_.get());
   capture_worker_thread_->Start();
 
@@ -1445,7 +1446,8 @@ int32_t AudioDeviceMac::StartPlayout() {
 
   RTC_DCHECK(!render_worker_thread_.get());
   render_worker_thread_.reset(new rtc::PlatformThread(
-      RunRender, this, "RenderWorkerThread", rtc::kRealtimePriority));
+      RunRender, this, "RenderWorkerThread",
+      rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)));
   render_worker_thread_->Start();
 
   if (_twoDevices || !_recording) {

modules/audio_device/win/core_audio_base_win.cc

@@ -9,15 +9,16 @@
  */
 
 #include "modules/audio_device/win/core_audio_base_win.h"
-#include "modules/audio_device/audio_device_buffer.h"
 
 #include <memory>
 #include <string>
 
+#include "modules/audio_device/audio_device_buffer.h"
 #include "rtc_base/arraysize.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/numerics/safe_conversions.h"
+#include "rtc_base/platform_thread.h"
 #include "rtc_base/time_utils.h"
 #include "rtc_base/win/scoped_com_initializer.h"
 #include "rtc_base/win/windows_version.h"
@@ -560,7 +561,7 @@ bool CoreAudioBase::Start() {
   if (!audio_thread_) {
     audio_thread_ = std::make_unique<rtc::PlatformThread>(
         Run, this, IsInput() ? "wasapi_capture_thread" : "wasapi_render_thread",
-        rtc::kRealtimePriority);
+        rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority));
     RTC_DCHECK(audio_thread_);
     audio_thread_->Start();
     if (!audio_thread_->IsRunning()) {

modules/audio_processing/audio_processing_impl_locking_unittest.cc

@@ -485,18 +485,21 @@ void PopulateAudioFrame(float amplitude,
 }
 
 AudioProcessingImplLockTest::AudioProcessingImplLockTest()
-    : render_thread_(RenderProcessorThreadFunc,
-                     this,
-                     "render",
-                     rtc::kRealtimePriority),
-      capture_thread_(CaptureProcessorThreadFunc,
-                      this,
-                      "capture",
-                      rtc::kRealtimePriority),
-      stats_thread_(StatsProcessorThreadFunc,
-                    this,
-                    "stats",
-                    rtc::kNormalPriority),
+    : render_thread_(
+          RenderProcessorThreadFunc,
+          this,
+          "render",
+          rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)),
+      capture_thread_(
+          CaptureProcessorThreadFunc,
+          this,
+          "capture",
+          rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)),
+      stats_thread_(
+          StatsProcessorThreadFunc,
+          this,
+          "stats",
+          rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority)),
       apm_(AudioProcessingBuilderForTesting().Create()),
       render_thread_state_(kMaxFrameSize,
                            &rand_gen_,

modules/audio_processing/audio_processing_performance_unittest.cc

@@ -391,14 +391,16 @@ class TimedThreadApiProcessor {
 class CallSimulator : public ::testing::TestWithParam<SimulationConfig> {
  public:
   CallSimulator()
-      : render_thread_(new rtc::PlatformThread(RenderProcessorThreadFunc,
-                                               this,
-                                               "render",
-                                               rtc::kRealtimePriority)),
-        capture_thread_(new rtc::PlatformThread(CaptureProcessorThreadFunc,
-                                                this,
-                                                "capture",
-                                                rtc::kRealtimePriority)),
+      : render_thread_(new rtc::PlatformThread(
+            RenderProcessorThreadFunc,
+            this,
+            "render",
+            rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority))),
+        capture_thread_(new rtc::PlatformThread(
+            CaptureProcessorThreadFunc,
+            this,
+            "capture",
+            rtc::ThreadAttributes().SetPriority(rtc::kRealtimePriority))),
         rand_gen_(42U),
         simulation_config_(static_cast<SimulationConfig>(GetParam())) {}
 

modules/video_capture/linux/video_capture_linux.cc

@@ -243,9 +243,9 @@ int32_t VideoCaptureModuleV4L2::StartCapture(
   // start capture thread;
   if (!_captureThread) {
     quit_ = false;
-    _captureThread.reset(
-        new rtc::PlatformThread(VideoCaptureModuleV4L2::CaptureThread, this,
-                                "CaptureThread", rtc::kHighPriority));
+    _captureThread.reset(new rtc::PlatformThread(
+        VideoCaptureModuleV4L2::CaptureThread, this, "CaptureThread",
+        rtc::ThreadAttributes().SetPriority(rtc::kHighPriority)));
     _captureThread->Start();
   }
 

rtc_base/BUILD.gn

@@ -238,7 +238,10 @@ rtc_library("platform_thread") {
     ":timeutils",
     "../api:sequence_checker",
   ]
-  absl_deps = [ "//third_party/abseil-cpp/absl/strings" ]
+  absl_deps = [
+    "//third_party/abseil-cpp/absl/memory",
+    "//third_party/abseil-cpp/absl/strings",
+  ]
 }
 
 rtc_library("rtc_event") {

rtc_base/event_tracer.cc

@@ -91,7 +91,7 @@ class EventLogger final {
       : logging_thread_(EventTracingThreadFunc,
                         this,
                         "EventTracingThread",
-                        kLowPriority) {}
+                        ThreadAttributes().SetPriority(kLowPriority)) {}
   ~EventLogger() { RTC_DCHECK(thread_checker_.IsCurrent()); }
 
   void AddTraceEvent(const char* name,

rtc_base/platform_thread.cc

@@ -10,6 +10,8 @@
 
 #include "rtc_base/platform_thread.h"
 
+#include <memory>
+
 #if !defined(WEBRTC_WIN)
 #include <sched.h>
 #endif
@@ -18,123 +20,22 @@
 
 #include <algorithm>
 
+#include "absl/memory/memory.h"
 #include "rtc_base/checks.h"
 
 namespace rtc {
+
 namespace {
-#if !defined(WEBRTC_WIN)
-struct ThreadAttributes {
-  ThreadAttributes() { pthread_attr_init(&attr); }
-  ~ThreadAttributes() { pthread_attr_destroy(&attr); }
-  pthread_attr_t* operator&() { return &attr; }
-  pthread_attr_t attr;
+struct ThreadStartData {
+  ThreadRunFunction run_function;
+  void* obj;
+  std::string thread_name;
+  ThreadPriority priority;
 };
-#endif  // defined(WEBRTC_WIN)
-}  // namespace
 
-PlatformThread::PlatformThread(ThreadRunFunction func,
-                               void* obj,
-                               absl::string_view thread_name,
-                               ThreadPriority priority /*= kNormalPriority*/)
-    : run_function_(func), priority_(priority), obj_(obj), name_(thread_name) {
-  RTC_DCHECK(func);
-  RTC_DCHECK(!name_.empty());
-  // TODO(tommi): Consider lowering the limit to 15 (limit on Linux).
-  RTC_DCHECK(name_.length() < 64);
-  spawned_thread_checker_.Detach();
-}
-
-PlatformThread::~PlatformThread() {
-  RTC_DCHECK(thread_checker_.IsCurrent());
+bool SetPriority(ThreadPriority priority) {
 #if defined(WEBRTC_WIN)
-  RTC_DCHECK(!thread_);
-  RTC_DCHECK(!thread_id_);
-#endif  // defined(WEBRTC_WIN)
-}
-
-#if defined(WEBRTC_WIN)
-DWORD WINAPI PlatformThread::StartThread(void* param) {
-  // The GetLastError() function only returns valid results when it is called
-  // after a Win32 API function that returns a "failed" result. A crash dump
-  // contains the result from GetLastError() and to make sure it does not
-  // falsely report a Windows error we call SetLastError here.
-  ::SetLastError(ERROR_SUCCESS);
-  static_cast<PlatformThread*>(param)->Run();
-  return 0;
-}
-#else
-void* PlatformThread::StartThread(void* param) {
-  static_cast<PlatformThread*>(param)->Run();
-  return 0;
-}
-#endif  // defined(WEBRTC_WIN)
-
-void PlatformThread::Start() {
-  RTC_DCHECK(thread_checker_.IsCurrent());
-  RTC_DCHECK(!thread_) << "Thread already started?";
-#if defined(WEBRTC_WIN)
-  // See bug 2902 for background on STACK_SIZE_PARAM_IS_A_RESERVATION.
-  // Set the reserved stack stack size to 1M, which is the default on Windows
-  // and Linux.
-  thread_ = ::CreateThread(nullptr, 1024 * 1024, &StartThread, this,
-                           STACK_SIZE_PARAM_IS_A_RESERVATION, &thread_id_);
-  RTC_CHECK(thread_) << "CreateThread failed";
-  RTC_DCHECK(thread_id_);
-#else
-  ThreadAttributes attr;
-  // Set the stack stack size to 1M.
-  pthread_attr_setstacksize(&attr, 1024 * 1024);
-  RTC_CHECK_EQ(0, pthread_create(&thread_, &attr, &StartThread, this));
-#endif  // defined(WEBRTC_WIN)
-}
-
-bool PlatformThread::IsRunning() const {
-  RTC_DCHECK(thread_checker_.IsCurrent());
-#if defined(WEBRTC_WIN)
-  return thread_ != nullptr;
-#else
-  return thread_ != 0;
-#endif  // defined(WEBRTC_WIN)
-}
-
-PlatformThreadRef PlatformThread::GetThreadRef() const {
-#if defined(WEBRTC_WIN)
-  return thread_id_;
-#else
-  return thread_;
-#endif  // defined(WEBRTC_WIN)
-}
-
-void PlatformThread::Stop() {
-  RTC_DCHECK(thread_checker_.IsCurrent());
-  if (!IsRunning())
-    return;
-
-#if defined(WEBRTC_WIN)
-  WaitForSingleObject(thread_, INFINITE);
-  CloseHandle(thread_);
-  thread_ = nullptr;
-  thread_id_ = 0;
-#else
-  RTC_CHECK_EQ(0, pthread_join(thread_, nullptr));
-  thread_ = 0;
-#endif  // defined(WEBRTC_WIN)
-  spawned_thread_checker_.Detach();
-}
-
-void PlatformThread::Run() {
-  // Attach the worker thread checker to this thread.
-  RTC_DCHECK(spawned_thread_checker_.IsCurrent());
-  rtc::SetCurrentThreadName(name_.c_str());
-  SetPriority(priority_);
-  run_function_(obj_);
-}
-
-bool PlatformThread::SetPriority(ThreadPriority priority) {
-  RTC_DCHECK(spawned_thread_checker_.IsCurrent());
-
-#if defined(WEBRTC_WIN)
-  return SetThreadPriority(thread_, priority) != FALSE;
+  return SetThreadPriority(GetCurrentThread(), priority) != FALSE;
 #elif defined(__native_client__) || defined(WEBRTC_FUCHSIA)
   // Setting thread priorities is not supported in NaCl or Fuchsia.
   return true;
@@ -176,13 +77,124 @@ bool PlatformThread::SetPriority(ThreadPriority priority) {
       param.sched_priority = top_prio;
       break;
   }
-  return pthread_setschedparam(thread_, policy, &param) == 0;
+  return pthread_setschedparam(pthread_self(), policy, &param) == 0;
+#endif  // defined(WEBRTC_WIN)
+}
+
+void RunPlatformThread(std::unique_ptr<ThreadStartData> data) {
+  rtc::SetCurrentThreadName(data->thread_name.c_str());
+  data->thread_name.clear();
+  SetPriority(data->priority);
+  data->run_function(data->obj);
+}
+
+#if defined(WEBRTC_WIN)
+DWORD WINAPI StartThread(void* param) {
+  // The GetLastError() function only returns valid results when it is called
+  // after a Win32 API function that returns a "failed" result. A crash dump
+  // contains the result from GetLastError() and to make sure it does not
+  // falsely report a Windows error we call SetLastError here.
+  ::SetLastError(ERROR_SUCCESS);
+  RunPlatformThread(absl::WrapUnique(static_cast<ThreadStartData*>(param)));
+  return 0;
+}
+#else
+void* StartThread(void* param) {
+  RunPlatformThread(absl::WrapUnique(static_cast<ThreadStartData*>(param)));
+  return 0;
+}
+#endif  // defined(WEBRTC_WIN)
+
+}  // namespace
+
+PlatformThread::PlatformThread(ThreadRunFunction func,
+                               void* obj,
+                               absl::string_view thread_name,
+                               ThreadAttributes attributes)
+    : run_function_(func),
+      attributes_(attributes),
+      obj_(obj),
+      name_(thread_name) {
+  RTC_DCHECK(func);
+  RTC_DCHECK(!name_.empty());
+  // TODO(tommi): Consider lowering the limit to 15 (limit on Linux).
+  RTC_DCHECK(name_.length() < 64);
+}
+
+PlatformThread::~PlatformThread() {
+  RTC_DCHECK_RUN_ON(&thread_checker_);
+  RTC_DCHECK(!thread_);
+#if defined(WEBRTC_WIN)
+  RTC_DCHECK(!thread_id_);
+#endif  // defined(WEBRTC_WIN)
+}
+
+void PlatformThread::Start() {
+  RTC_DCHECK_RUN_ON(&thread_checker_);
+  RTC_DCHECK(!thread_) << "Thread already started?";
+  ThreadStartData* data =
+      new ThreadStartData{run_function_, obj_, name_, attributes_.priority};
+#if defined(WEBRTC_WIN)
+  // See bug 2902 for background on STACK_SIZE_PARAM_IS_A_RESERVATION.
+  // Set the reserved stack stack size to 1M, which is the default on Windows
+  // and Linux.
+  thread_ = ::CreateThread(nullptr, 1024 * 1024, &StartThread, data,
+                           STACK_SIZE_PARAM_IS_A_RESERVATION, &thread_id_);
+  RTC_CHECK(thread_) << "CreateThread failed";
+  RTC_DCHECK(thread_id_);
+#else
+  pthread_attr_t attr;
+  pthread_attr_init(&attr);
+  // Set the stack stack size to 1M.
+  pthread_attr_setstacksize(&attr, 1024 * 1024);
+  pthread_attr_setdetachstate(&attr, attributes_.joinable
+                                         ? PTHREAD_CREATE_JOINABLE
+                                         : PTHREAD_CREATE_DETACHED);
+  RTC_CHECK_EQ(0, pthread_create(&thread_, &attr, &StartThread, data));
+  pthread_attr_destroy(&attr);
+#endif  // defined(WEBRTC_WIN)
+}
+
+bool PlatformThread::IsRunning() const {
+  RTC_DCHECK_RUN_ON(&thread_checker_);
+#if defined(WEBRTC_WIN)
+  return thread_ != nullptr;
+#else
+  return thread_ != 0;
+#endif  // defined(WEBRTC_WIN)
+}
+
+PlatformThreadRef PlatformThread::GetThreadRef() const {
+#if defined(WEBRTC_WIN)
+  return thread_id_;
+#else
+  return thread_;
+#endif  // defined(WEBRTC_WIN)
+}
+
+void PlatformThread::Stop() {
+  RTC_DCHECK_RUN_ON(&thread_checker_);
+  if (!IsRunning())
+    return;
+
+#if defined(WEBRTC_WIN)
+  if (attributes_.joinable) {
+    WaitForSingleObject(thread_, INFINITE);
+  }
+  CloseHandle(thread_);
+  thread_ = nullptr;
+  thread_id_ = 0;
+#else
+  if (attributes_.joinable) {
+    RTC_CHECK_EQ(0, pthread_join(thread_, nullptr));
+  }
+  thread_ = 0;
 #endif  // defined(WEBRTC_WIN)
 }
 
 #if defined(WEBRTC_WIN)
 bool PlatformThread::QueueAPC(PAPCFUNC function, ULONG_PTR data) {
-  RTC_DCHECK(thread_checker_.IsCurrent());
+  RTC_DCHECK_RUN_ON(&thread_checker_);
   RTC_DCHECK(IsRunning());
 
   return QueueUserAPC(function, thread_, data) != FALSE;

rtc_base/platform_thread.h

@@ -42,6 +42,20 @@ enum ThreadPriority {
 #endif
 };
 
+struct ThreadAttributes {
+  ThreadPriority priority = kNormalPriority;
+  bool joinable = true;
+
+  ThreadAttributes& SetPriority(ThreadPriority priority_param) {
+    priority = priority_param;
+    return *this;
+  }
+  ThreadAttributes& SetDetached() {
+    joinable = false;
+    return *this;
+  }
+};
+
 // Represents a simple worker thread.  The implementation must be assumed
 // to be single threaded, meaning that all methods of the class, must be
 // called from the same thread, including instantiation.
@@ -50,13 +64,14 @@ class PlatformThread {
   PlatformThread(ThreadRunFunction func,
                  void* obj,
                  absl::string_view thread_name,
-                 ThreadPriority priority = kNormalPriority);
+                 ThreadAttributes attributes = ThreadAttributes());
   virtual ~PlatformThread();
 
   const std::string& name() const { return name_; }
 
   // Spawns a thread and tries to set thread priority according to the priority
   // from when CreateThread was called.
+  // Start can only be called after the constructor or after a call to Stop().
   void Start();
 
   bool IsRunning() const;
@@ -65,7 +80,11 @@ class PlatformThread {
   // thread checks.
   PlatformThreadRef GetThreadRef() const;
 
-  // Stops (joins) the spawned thread.
+  // Stop() prepares the PlatformThread for destruction or another call to
+  // Start(). For a PlatformThread that's been created with
+  // ThreadAttributes::joinable true (the default), Stop() suspends the calling
+  // thread until the created thread exits unless the thread has already exited.
+  // Stop() can only be called after calling Start().
   void Stop();
 
  protected:
@@ -75,25 +94,17 @@ class PlatformThread {
 #endif
 
  private:
-  void Run();
-  bool SetPriority(ThreadPriority priority);
-
   ThreadRunFunction const run_function_ = nullptr;
-  const ThreadPriority priority_ = kNormalPriority;
+  const ThreadAttributes attributes_;
   void* const obj_;
   // TODO(pbos): Make sure call sites use string literals and update to a const
   // char* instead of a std::string.
   const std::string name_;
   webrtc::SequenceChecker thread_checker_;
-  webrtc::SequenceChecker spawned_thread_checker_;
 #if defined(WEBRTC_WIN)
-  static DWORD WINAPI StartThread(void* param);
-
   HANDLE thread_ = nullptr;
   DWORD thread_id_ = 0;
 #else
-  static void* StartThread(void* param);
-
   pthread_t thread_ = 0;
 #endif  // defined(WEBRTC_WIN)
   RTC_DISALLOW_COPY_AND_ASSIGN(PlatformThread);

rtc_base/platform_thread_unittest.cc

@@ -10,7 +10,9 @@
 
 #include "rtc_base/platform_thread.h"
 
-#include "test/gtest.h"
+#include "rtc_base/event.h"
+#include "system_wrappers/include/sleep.h"
+#include "test/gmock.h"
 
 namespace rtc {
 namespace {
@@ -23,6 +25,11 @@ void SetFlagRunFunction(void* obj) {
   *obj_as_bool = true;
 }
 
+void StdFunctionRunFunction(void* obj) {
+  std::function<void()>* fun = static_cast<std::function<void()>*>(obj);
+  (*fun)();
+}
+
 }  // namespace
 
 TEST(PlatformThreadTest, StartStop) {
@@ -58,4 +65,41 @@ TEST(PlatformThreadTest, RunFunctionIsCalled) {
   EXPECT_TRUE(flag);
 }
 
+TEST(PlatformThreadTest, JoinsThread) {
+  // This test flakes if there are problems with the join implementation.
+  EXPECT_TRUE(ThreadAttributes().joinable);
+  rtc::Event event;
+  std::function<void()> thread_function = [&] { event.Set(); };
+  PlatformThread thread(&StdFunctionRunFunction, &thread_function, "T");
+  thread.Start();
+  thread.Stop();
+  EXPECT_TRUE(event.Wait(/*give_up_after_ms=*/0));
+}
+
+TEST(PlatformThreadTest, StopsBeforeDetachedThreadExits) {
+  // This test flakes if there are problems with the detached thread
+  // implementation.
+  bool flag = false;
+  rtc::Event thread_started;
+  rtc::Event thread_continue;
+  rtc::Event thread_exiting;
+  std::function<void()> thread_function = [&] {
+    thread_started.Set();
+    thread_continue.Wait(Event::kForever);
+    flag = true;
+    thread_exiting.Set();
+  };
+  {
+    PlatformThread thread(&StdFunctionRunFunction, &thread_function, "T",
+                          ThreadAttributes().SetDetached());
+    thread.Start();
+    thread.Stop();
+  }
+  thread_started.Wait(Event::kForever);
+  EXPECT_FALSE(flag);
+  thread_continue.Set();
+  thread_exiting.Wait(Event::kForever);
+  EXPECT_TRUE(flag);
+}
+
 }  // namespace rtc

rtc_base/task_queue_libevent.cc

@@ -173,7 +173,10 @@ class TaskQueueLibevent::SetTimerTask : public QueuedTask {
 TaskQueueLibevent::TaskQueueLibevent(absl::string_view queue_name,
                                      rtc::ThreadPriority priority)
     : event_base_(event_base_new()),
-      thread_(&TaskQueueLibevent::ThreadMain, this, queue_name, priority) {
+      thread_(&TaskQueueLibevent::ThreadMain,
+              this,
+              queue_name,
+              rtc::ThreadAttributes().SetPriority(priority)) {
   int fds[2];
   RTC_CHECK(pipe(fds) == 0);
   SetNonBlocking(fds[0]);

rtc_base/task_queue_stdlib.cc

@@ -126,7 +126,10 @@ TaskQueueStdlib::TaskQueueStdlib(absl::string_view queue_name,
     : started_(/*manual_reset=*/false, /*initially_signaled=*/false),
       stopped_(/*manual_reset=*/false, /*initially_signaled=*/false),
       flag_notify_(/*manual_reset=*/false, /*initially_signaled=*/false),
-      thread_(&TaskQueueStdlib::ThreadMain, this, queue_name, priority) {
+      thread_(&TaskQueueStdlib::ThreadMain,
+              this,
+              queue_name,
+              rtc::ThreadAttributes().SetPriority(priority)) {
   thread_.Start();
   started_.Wait(rtc::Event::kForever);
 }

rtc_base/task_queue_win.cc

@@ -175,7 +175,10 @@ class TaskQueueWin : public TaskQueueBase {
                  void* obj,
                  absl::string_view thread_name,
                  rtc::ThreadPriority priority)
-        : PlatformThread(func, obj, thread_name, priority) {}
+        : PlatformThread(func,
+                         obj,
+                         thread_name,
+                         rtc::ThreadAttributes().SetPriority(priority)) {}
 
     bool QueueAPC(PAPCFUNC apc_function, ULONG_PTR data) {
       return rtc::PlatformThread::QueueAPC(apc_function, data);

test/pc/e2e/analyzer/video/default_video_quality_analyzer.cc

@@ -21,6 +21,7 @@
 #include "common_video/libyuv/include/webrtc_libyuv.h"
 #include "rtc_base/cpu_time.h"
 #include "rtc_base/logging.h"
+#include "rtc_base/platform_thread.h"
 #include "rtc_base/strings/string_builder.h"
 #include "rtc_base/time_utils.h"
 #include "rtc_tools/frame_analyzer/video_geometry_aligner.h"
@@ -144,7 +145,7 @@ void DefaultVideoQualityAnalyzer::Start(
     auto thread = std::make_unique<rtc::PlatformThread>(
         &DefaultVideoQualityAnalyzer::ProcessComparisonsThread, this,
         ("DefaultVideoQualityAnalyzerWorker-" + std::to_string(i)).data(),
-        rtc::ThreadPriority::kNormalPriority);
+        rtc::ThreadAttributes().SetPriority(rtc::kNormalPriority));
     thread->Start();
     thread_pool_.push_back(std::move(thread));
   }