blob: e1db2bc24f9426dfa38f79527bb2d27b9a5e7e64 [file] [log] [blame]
/*
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "rtc_base/thread.h"
#include "absl/strings/string_view.h"
#if defined(WEBRTC_WIN)
#include <comdef.h>
#elif defined(WEBRTC_POSIX)
#include <time.h>
#else
#error "Either WEBRTC_WIN or WEBRTC_POSIX needs to be defined."
#endif
#if defined(WEBRTC_WIN)
// Disable warning that we don't care about:
// warning C4722: destructor never returns, potential memory leak
#pragma warning(disable : 4722)
#endif
#include <stdio.h>
#include <utility>
#include "absl/algorithm/container.h"
#include "api/sequence_checker.h"
#include "api/task_queue/to_queued_task.h"
#include "rtc_base/checks.h"
#include "rtc_base/deprecated/recursive_critical_section.h"
#include "rtc_base/event.h"
#include "rtc_base/internal/default_socket_server.h"
#include "rtc_base/logging.h"
#include "rtc_base/null_socket_server.h"
#include "rtc_base/time_utils.h"
#include "rtc_base/trace_event.h"
#if defined(WEBRTC_MAC)
#include "rtc_base/system/cocoa_threading.h"
/*
* These are forward-declarations for methods that are part of the
* ObjC runtime. They are declared in the private header objc-internal.h.
* These calls are what clang inserts when using @autoreleasepool in ObjC,
* but here they are used directly in order to keep this file C++.
* https://clang.llvm.org/docs/AutomaticReferenceCounting.html#runtime-support
*/
extern "C" {
void* objc_autoreleasePoolPush(void);
void objc_autoreleasePoolPop(void* pool);
}
namespace {
class ScopedAutoReleasePool {
public:
ScopedAutoReleasePool() : pool_(objc_autoreleasePoolPush()) {}
~ScopedAutoReleasePool() { objc_autoreleasePoolPop(pool_); }
private:
void* const pool_;
};
} // namespace
#endif
namespace rtc {
namespace {
class MessageHandlerWithTask final : public MessageHandler {
public:
MessageHandlerWithTask() {}
MessageHandlerWithTask(const MessageHandlerWithTask&) = delete;
MessageHandlerWithTask& operator=(const MessageHandlerWithTask&) = delete;
void OnMessage(Message* msg) override {
static_cast<rtc_thread_internal::MessageLikeTask*>(msg->pdata)->Run();
delete msg->pdata;
}
private:
~MessageHandlerWithTask() override {}
};
class RTC_SCOPED_LOCKABLE MarkProcessingCritScope {
public:
MarkProcessingCritScope(const RecursiveCriticalSection* cs,
size_t* processing) RTC_EXCLUSIVE_LOCK_FUNCTION(cs)
: cs_(cs), processing_(processing) {
cs_->Enter();
*processing_ += 1;
}
~MarkProcessingCritScope() RTC_UNLOCK_FUNCTION() {
*processing_ -= 1;
cs_->Leave();
}
MarkProcessingCritScope(const MarkProcessingCritScope&) = delete;
MarkProcessingCritScope& operator=(const MarkProcessingCritScope&) = delete;
private:
const RecursiveCriticalSection* const cs_;
size_t* processing_;
};
} // namespace
ThreadManager* ThreadManager::Instance() {
static ThreadManager* const thread_manager = new ThreadManager();
return thread_manager;
}
ThreadManager::~ThreadManager() {
// By above RTC_DEFINE_STATIC_LOCAL.
RTC_DCHECK_NOTREACHED() << "ThreadManager should never be destructed.";
}
// static
void ThreadManager::Add(Thread* message_queue) {
return Instance()->AddInternal(message_queue);
}
void ThreadManager::AddInternal(Thread* message_queue) {
CritScope cs(&crit_);
// Prevent changes while the list of message queues is processed.
RTC_DCHECK_EQ(processing_, 0);
message_queues_.push_back(message_queue);
}
// static
void ThreadManager::Remove(Thread* message_queue) {
return Instance()->RemoveInternal(message_queue);
}
void ThreadManager::RemoveInternal(Thread* message_queue) {
{
CritScope cs(&crit_);
// Prevent changes while the list of message queues is processed.
RTC_DCHECK_EQ(processing_, 0);
std::vector<Thread*>::iterator iter;
iter = absl::c_find(message_queues_, message_queue);
if (iter != message_queues_.end()) {
message_queues_.erase(iter);
}
#if RTC_DCHECK_IS_ON
RemoveFromSendGraph(message_queue);
#endif
}
}
#if RTC_DCHECK_IS_ON
void ThreadManager::RemoveFromSendGraph(Thread* thread) {
for (auto it = send_graph_.begin(); it != send_graph_.end();) {
if (it->first == thread) {
it = send_graph_.erase(it);
} else {
it->second.erase(thread);
++it;
}
}
}
void ThreadManager::RegisterSendAndCheckForCycles(Thread* source,
Thread* target) {
RTC_DCHECK(source);
RTC_DCHECK(target);
CritScope cs(&crit_);
std::deque<Thread*> all_targets({target});
// We check the pre-existing who-sends-to-who graph for any path from target
// to source. This loop is guaranteed to terminate because per the send graph
// invariant, there are no cycles in the graph.
for (size_t i = 0; i < all_targets.size(); i++) {
const auto& targets = send_graph_[all_targets[i]];
all_targets.insert(all_targets.end(), targets.begin(), targets.end());
}
RTC_CHECK_EQ(absl::c_count(all_targets, source), 0)
<< " send loop between " << source->name() << " and " << target->name();
// We may now insert source -> target without creating a cycle, since there
// was no path from target to source per the prior CHECK.
send_graph_[source].insert(target);
}
#endif
// static
void ThreadManager::Clear(MessageHandler* handler) {
return Instance()->ClearInternal(handler);
}
void ThreadManager::ClearInternal(MessageHandler* handler) {
// Deleted objects may cause re-entrant calls to ClearInternal. This is
// allowed as the list of message queues does not change while queues are
// cleared.
MarkProcessingCritScope cs(&crit_, &processing_);
for (Thread* queue : message_queues_) {
queue->Clear(handler);
}
}
// static
void ThreadManager::ProcessAllMessageQueuesForTesting() {
return Instance()->ProcessAllMessageQueuesInternal();
}
void ThreadManager::ProcessAllMessageQueuesInternal() {
// This works by posting a delayed message at the current time and waiting
// for it to be dispatched on all queues, which will ensure that all messages
// that came before it were also dispatched.
std::atomic<int> queues_not_done(0);
// This class is used so that whether the posted message is processed, or the
// message queue is simply cleared, queues_not_done gets decremented.
class ScopedIncrement : public MessageData {
public:
ScopedIncrement(std::atomic<int>* value) : value_(value) {
value_->fetch_add(1);
}
~ScopedIncrement() override { value_->fetch_sub(1); }
private:
std::atomic<int>* value_;
};
{
MarkProcessingCritScope cs(&crit_, &processing_);
for (Thread* queue : message_queues_) {
if (!queue->IsProcessingMessagesForTesting()) {
// If the queue is not processing messages, it can
// be ignored. If we tried to post a message to it, it would be dropped
// or ignored.
continue;
}
queue->PostDelayed(RTC_FROM_HERE, 0, nullptr, MQID_DISPOSE,
new ScopedIncrement(&queues_not_done));
}
}
rtc::Thread* current = rtc::Thread::Current();
// Note: One of the message queues may have been on this thread, which is
// why we can't synchronously wait for queues_not_done to go to 0; we need
// to process messages as well.
while (queues_not_done.load() > 0) {
if (current) {
current->ProcessMessages(0);
}
}
}
// static
Thread* Thread::Current() {
ThreadManager* manager = ThreadManager::Instance();
Thread* thread = manager->CurrentThread();
return thread;
}
#if defined(WEBRTC_POSIX)
ThreadManager::ThreadManager() {
#if defined(WEBRTC_MAC)
InitCocoaMultiThreading();
#endif
pthread_key_create(&key_, nullptr);
}
Thread* ThreadManager::CurrentThread() {
return static_cast<Thread*>(pthread_getspecific(key_));
}
void ThreadManager::SetCurrentThreadInternal(Thread* thread) {
pthread_setspecific(key_, thread);
}
#endif
#if defined(WEBRTC_WIN)
ThreadManager::ThreadManager() : key_(TlsAlloc()) {}
Thread* ThreadManager::CurrentThread() {
return static_cast<Thread*>(TlsGetValue(key_));
}
void ThreadManager::SetCurrentThreadInternal(Thread* thread) {
TlsSetValue(key_, thread);
}
#endif
void ThreadManager::SetCurrentThread(Thread* thread) {
#if RTC_DLOG_IS_ON
if (CurrentThread() && thread) {
RTC_DLOG(LS_ERROR) << "SetCurrentThread: Overwriting an existing value?";
}
#endif // RTC_DLOG_IS_ON
if (thread) {
thread->EnsureIsCurrentTaskQueue();
} else {
Thread* current = CurrentThread();
if (current) {
// The current thread is being cleared, e.g. as a result of
// UnwrapCurrent() being called or when a thread is being stopped
// (see PreRun()). This signals that the Thread instance is being detached
// from the thread, which also means that TaskQueue::Current() must not
// return a pointer to the Thread instance.
current->ClearCurrentTaskQueue();
}
}
SetCurrentThreadInternal(thread);
}
void rtc::ThreadManager::ChangeCurrentThreadForTest(rtc::Thread* thread) {
SetCurrentThreadInternal(thread);
}
Thread* ThreadManager::WrapCurrentThread() {
Thread* result = CurrentThread();
if (nullptr == result) {
result = new Thread(CreateDefaultSocketServer());
result->WrapCurrentWithThreadManager(this, true);
}
return result;
}
void ThreadManager::UnwrapCurrentThread() {
Thread* t = CurrentThread();
if (t && !(t->IsOwned())) {
t->UnwrapCurrent();
delete t;
}
}
Thread::ScopedDisallowBlockingCalls::ScopedDisallowBlockingCalls()
: thread_(Thread::Current()),
previous_state_(thread_->SetAllowBlockingCalls(false)) {}
Thread::ScopedDisallowBlockingCalls::~ScopedDisallowBlockingCalls() {
RTC_DCHECK(thread_->IsCurrent());
thread_->SetAllowBlockingCalls(previous_state_);
}
#if RTC_DCHECK_IS_ON
Thread::ScopedCountBlockingCalls::ScopedCountBlockingCalls(
std::function<void(uint32_t, uint32_t)> callback)
: thread_(Thread::Current()),
base_blocking_call_count_(thread_->GetBlockingCallCount()),
base_could_be_blocking_call_count_(
thread_->GetCouldBeBlockingCallCount()),
result_callback_(std::move(callback)) {}
Thread::ScopedCountBlockingCalls::~ScopedCountBlockingCalls() {
if (GetTotalBlockedCallCount() >= min_blocking_calls_for_callback_) {
result_callback_(GetBlockingCallCount(), GetCouldBeBlockingCallCount());
}
}
uint32_t Thread::ScopedCountBlockingCalls::GetBlockingCallCount() const {
return thread_->GetBlockingCallCount() - base_blocking_call_count_;
}
uint32_t Thread::ScopedCountBlockingCalls::GetCouldBeBlockingCallCount() const {
return thread_->GetCouldBeBlockingCallCount() -
base_could_be_blocking_call_count_;
}
uint32_t Thread::ScopedCountBlockingCalls::GetTotalBlockedCallCount() const {
return GetBlockingCallCount() + GetCouldBeBlockingCallCount();
}
#endif
Thread::Thread(SocketServer* ss) : Thread(ss, /*do_init=*/true) {}
Thread::Thread(std::unique_ptr<SocketServer> ss)
: Thread(std::move(ss), /*do_init=*/true) {}
Thread::Thread(SocketServer* ss, bool do_init)
: fPeekKeep_(false),
delayed_next_num_(0),
fInitialized_(false),
fDestroyed_(false),
stop_(0),
ss_(ss) {
RTC_DCHECK(ss);
ss_->SetMessageQueue(this);
SetName("Thread", this); // default name
if (do_init) {
DoInit();
}
}
Thread::Thread(std::unique_ptr<SocketServer> ss, bool do_init)
: Thread(ss.get(), do_init) {
own_ss_ = std::move(ss);
}
Thread::~Thread() {
Stop();
DoDestroy();
}
void Thread::DoInit() {
if (fInitialized_) {
return;
}
fInitialized_ = true;
ThreadManager::Add(this);
}
void Thread::DoDestroy() {
if (fDestroyed_) {
return;
}
fDestroyed_ = true;
// The signal is done from here to ensure
// that it always gets called when the queue
// is going away.
if (ss_) {
ss_->SetMessageQueue(nullptr);
}
ThreadManager::Remove(this);
ClearInternal(nullptr, MQID_ANY, nullptr);
}
SocketServer* Thread::socketserver() {
return ss_;
}
void Thread::WakeUpSocketServer() {
ss_->WakeUp();
}
void Thread::Quit() {
stop_.store(1, std::memory_order_release);
WakeUpSocketServer();
}
bool Thread::IsQuitting() {
return stop_.load(std::memory_order_acquire) != 0;
}
void Thread::Restart() {
stop_.store(0, std::memory_order_release);
}
bool Thread::Peek(Message* pmsg, int cmsWait) {
if (fPeekKeep_) {
*pmsg = msgPeek_;
return true;
}
if (!Get(pmsg, cmsWait))
return false;
msgPeek_ = *pmsg;
fPeekKeep_ = true;
return true;
}
bool Thread::Get(Message* pmsg, int cmsWait, bool process_io) {
// Return and clear peek if present
// Always return the peek if it exists so there is Peek/Get symmetry
if (fPeekKeep_) {
*pmsg = msgPeek_;
fPeekKeep_ = false;
return true;
}
// Get w/wait + timer scan / dispatch + socket / event multiplexer dispatch
int64_t cmsTotal = cmsWait;
int64_t cmsElapsed = 0;
int64_t msStart = TimeMillis();
int64_t msCurrent = msStart;
while (true) {
// Check for posted events
int64_t cmsDelayNext = kForever;
bool first_pass = true;
while (true) {
// All queue operations need to be locked, but nothing else in this loop
// (specifically handling disposed message) can happen inside the crit.
// Otherwise, disposed MessageHandlers will cause deadlocks.
{
CritScope cs(&crit_);
// On the first pass, check for delayed messages that have been
// triggered and calculate the next trigger time.
if (first_pass) {
first_pass = false;
while (!delayed_messages_.empty()) {
if (msCurrent < delayed_messages_.top().run_time_ms_) {
cmsDelayNext =
TimeDiff(delayed_messages_.top().run_time_ms_, msCurrent);
break;
}
messages_.push_back(delayed_messages_.top().msg_);
delayed_messages_.pop();
}
}
// Pull a message off the message queue, if available.
if (messages_.empty()) {
break;
} else {
*pmsg = messages_.front();
messages_.pop_front();
}
} // crit_ is released here.
// If this was a dispose message, delete it and skip it.
if (MQID_DISPOSE == pmsg->message_id) {
RTC_DCHECK(nullptr == pmsg->phandler);
delete pmsg->pdata;
*pmsg = Message();
continue;
}
return true;
}
if (IsQuitting())
break;
// Which is shorter, the delay wait or the asked wait?
int64_t cmsNext;
if (cmsWait == kForever) {
cmsNext = cmsDelayNext;
} else {
cmsNext = std::max<int64_t>(0, cmsTotal - cmsElapsed);
if ((cmsDelayNext != kForever) && (cmsDelayNext < cmsNext))
cmsNext = cmsDelayNext;
}
{
// Wait and multiplex in the meantime
if (!ss_->Wait(static_cast<int>(cmsNext), process_io))
return false;
}
// If the specified timeout expired, return
msCurrent = TimeMillis();
cmsElapsed = TimeDiff(msCurrent, msStart);
if (cmsWait != kForever) {
if (cmsElapsed >= cmsWait)
return false;
}
}
return false;
}
void Thread::Post(const Location& posted_from,
MessageHandler* phandler,
uint32_t id,
MessageData* pdata,
bool time_sensitive) {
RTC_DCHECK(!time_sensitive);
if (IsQuitting()) {
delete pdata;
return;
}
// Keep thread safe
// Add the message to the end of the queue
// Signal for the multiplexer to return
{
CritScope cs(&crit_);
Message msg;
msg.posted_from = posted_from;
msg.phandler = phandler;
msg.message_id = id;
msg.pdata = pdata;
messages_.push_back(msg);
}
WakeUpSocketServer();
}
void Thread::PostDelayed(const Location& posted_from,
int delay_ms,
MessageHandler* phandler,
uint32_t id,
MessageData* pdata) {
return DoDelayPost(posted_from, delay_ms, TimeAfter(delay_ms), phandler, id,
pdata);
}
void Thread::PostAt(const Location& posted_from,
int64_t run_at_ms,
MessageHandler* phandler,
uint32_t id,
MessageData* pdata) {
return DoDelayPost(posted_from, TimeUntil(run_at_ms), run_at_ms, phandler, id,
pdata);
}
void Thread::DoDelayPost(const Location& posted_from,
int64_t delay_ms,
int64_t run_at_ms,
MessageHandler* phandler,
uint32_t id,
MessageData* pdata) {
if (IsQuitting()) {
delete pdata;
return;
}
// Keep thread safe
// Add to the priority queue. Gets sorted soonest first.
// Signal for the multiplexer to return.
{
CritScope cs(&crit_);
Message msg;
msg.posted_from = posted_from;
msg.phandler = phandler;
msg.message_id = id;
msg.pdata = pdata;
DelayedMessage delayed(delay_ms, run_at_ms, delayed_next_num_, msg);
delayed_messages_.push(delayed);
// If this message queue processes 1 message every millisecond for 50 days,
// we will wrap this number. Even then, only messages with identical times
// will be misordered, and then only briefly. This is probably ok.
++delayed_next_num_;
RTC_DCHECK_NE(0, delayed_next_num_);
}
WakeUpSocketServer();
}
int Thread::GetDelay() {
CritScope cs(&crit_);
if (!messages_.empty())
return 0;
if (!delayed_messages_.empty()) {
int delay = TimeUntil(delayed_messages_.top().run_time_ms_);
if (delay < 0)
delay = 0;
return delay;
}
return kForever;
}
void Thread::ClearInternal(MessageHandler* phandler,
uint32_t id,
MessageList* removed) {
// Remove messages with phandler
if (fPeekKeep_ && msgPeek_.Match(phandler, id)) {
if (removed) {
removed->push_back(msgPeek_);
} else {
delete msgPeek_.pdata;
}
fPeekKeep_ = false;
}
// Remove from ordered message queue
for (auto it = messages_.begin(); it != messages_.end();) {
if (it->Match(phandler, id)) {
if (removed) {
removed->push_back(*it);
} else {
delete it->pdata;
}
it = messages_.erase(it);
} else {
++it;
}
}
// Remove from priority queue. Not directly iterable, so use this approach
auto new_end = delayed_messages_.container().begin();
for (auto it = new_end; it != delayed_messages_.container().end(); ++it) {
if (it->msg_.Match(phandler, id)) {
if (removed) {
removed->push_back(it->msg_);
} else {
delete it->msg_.pdata;
}
} else {
*new_end++ = *it;
}
}
delayed_messages_.container().erase(new_end,
delayed_messages_.container().end());
delayed_messages_.reheap();
}
void Thread::Dispatch(Message* pmsg) {
TRACE_EVENT2("webrtc", "Thread::Dispatch", "src_file",
pmsg->posted_from.file_name(), "src_func",
pmsg->posted_from.function_name());
RTC_DCHECK_RUN_ON(this);
int64_t start_time = TimeMillis();
pmsg->phandler->OnMessage(pmsg);
int64_t end_time = TimeMillis();
int64_t diff = TimeDiff(end_time, start_time);
if (diff >= dispatch_warning_ms_) {
RTC_LOG(LS_INFO) << "Message to " << name() << " took " << diff
<< "ms to dispatch. Posted from: "
<< pmsg->posted_from.ToString();
// To avoid log spew, move the warning limit to only give warning
// for delays that are larger than the one observed.
dispatch_warning_ms_ = diff + 1;
}
}
bool Thread::IsCurrent() const {
return ThreadManager::Instance()->CurrentThread() == this;
}
std::unique_ptr<Thread> Thread::CreateWithSocketServer() {
return std::unique_ptr<Thread>(new Thread(CreateDefaultSocketServer()));
}
std::unique_ptr<Thread> Thread::Create() {
return std::unique_ptr<Thread>(
new Thread(std::unique_ptr<SocketServer>(new NullSocketServer())));
}
bool Thread::SleepMs(int milliseconds) {
AssertBlockingIsAllowedOnCurrentThread();
#if defined(WEBRTC_WIN)
::Sleep(milliseconds);
return true;
#else
// POSIX has both a usleep() and a nanosleep(), but the former is deprecated,
// so we use nanosleep() even though it has greater precision than necessary.
struct timespec ts;
ts.tv_sec = milliseconds / 1000;
ts.tv_nsec = (milliseconds % 1000) * 1000000;
int ret = nanosleep(&ts, nullptr);
if (ret != 0) {
RTC_LOG_ERR(LS_WARNING) << "nanosleep() returning early";
return false;
}
return true;
#endif
}
bool Thread::SetName(absl::string_view name, const void* obj) {
RTC_DCHECK(!IsRunning());
name_ = std::string(name);
if (obj) {
// The %p specifier typically produce at most 16 hex digits, possibly with a
// 0x prefix. But format is implementation defined, so add some margin.
char buf[30];
snprintf(buf, sizeof(buf), " 0x%p", obj);
name_ += buf;
}
return true;
}
void Thread::SetDispatchWarningMs(int deadline) {
if (!IsCurrent()) {
PostTask(webrtc::ToQueuedTask(
[this, deadline]() { SetDispatchWarningMs(deadline); }));
return;
}
RTC_DCHECK_RUN_ON(this);
dispatch_warning_ms_ = deadline;
}
bool Thread::Start() {
RTC_DCHECK(!IsRunning());
if (IsRunning())
return false;
Restart(); // reset IsQuitting() if the thread is being restarted
// Make sure that ThreadManager is created on the main thread before
// we start a new thread.
ThreadManager::Instance();
owned_ = true;
#if defined(WEBRTC_WIN)
thread_ = CreateThread(nullptr, 0, PreRun, this, 0, &thread_id_);
if (!thread_) {
return false;
}
#elif defined(WEBRTC_POSIX)
pthread_attr_t attr;
pthread_attr_init(&attr);
int error_code = pthread_create(&thread_, &attr, PreRun, this);
if (0 != error_code) {
RTC_LOG(LS_ERROR) << "Unable to create pthread, error " << error_code;
thread_ = 0;
return false;
}
RTC_DCHECK(thread_);
#endif
return true;
}
bool Thread::WrapCurrent() {
return WrapCurrentWithThreadManager(ThreadManager::Instance(), true);
}
void Thread::UnwrapCurrent() {
// Clears the platform-specific thread-specific storage.
ThreadManager::Instance()->SetCurrentThread(nullptr);
#if defined(WEBRTC_WIN)
if (thread_ != nullptr) {
if (!CloseHandle(thread_)) {
RTC_LOG_GLE(LS_ERROR)
<< "When unwrapping thread, failed to close handle.";
}
thread_ = nullptr;
thread_id_ = 0;
}
#elif defined(WEBRTC_POSIX)
thread_ = 0;
#endif
}
void Thread::SafeWrapCurrent() {
WrapCurrentWithThreadManager(ThreadManager::Instance(), false);
}
void Thread::Join() {
if (!IsRunning())
return;
RTC_DCHECK(!IsCurrent());
if (Current() && !Current()->blocking_calls_allowed_) {
RTC_LOG(LS_WARNING) << "Waiting for the thread to join, "
"but blocking calls have been disallowed";
}
#if defined(WEBRTC_WIN)
RTC_DCHECK(thread_ != nullptr);
WaitForSingleObject(thread_, INFINITE);
CloseHandle(thread_);
thread_ = nullptr;
thread_id_ = 0;
#elif defined(WEBRTC_POSIX)
pthread_join(thread_, nullptr);
thread_ = 0;
#endif
}
bool Thread::SetAllowBlockingCalls(bool allow) {
RTC_DCHECK(IsCurrent());
bool previous = blocking_calls_allowed_;
blocking_calls_allowed_ = allow;
return previous;
}
// static
void Thread::AssertBlockingIsAllowedOnCurrentThread() {
#if !defined(NDEBUG)
Thread* current = Thread::Current();
RTC_DCHECK(!current || current->blocking_calls_allowed_);
#endif
}
// static
#if defined(WEBRTC_WIN)
DWORD WINAPI Thread::PreRun(LPVOID pv) {
#else
void* Thread::PreRun(void* pv) {
#endif
Thread* thread = static_cast<Thread*>(pv);
ThreadManager::Instance()->SetCurrentThread(thread);
rtc::SetCurrentThreadName(thread->name_.c_str());
#if defined(WEBRTC_MAC)
ScopedAutoReleasePool pool;
#endif
thread->Run();
ThreadManager::Instance()->SetCurrentThread(nullptr);
#ifdef WEBRTC_WIN
return 0;
#else
return nullptr;
#endif
} // namespace rtc
void Thread::Run() {
ProcessMessages(kForever);
}
bool Thread::IsOwned() {
RTC_DCHECK(IsRunning());
return owned_;
}
void Thread::Stop() {
Thread::Quit();
Join();
}
void Thread::Send(const Location& posted_from,
MessageHandler* phandler,
uint32_t id,
MessageData* pdata) {
RTC_DCHECK(!IsQuitting());
if (IsQuitting())
return;
// Sent messages are sent to the MessageHandler directly, in the context
// of "thread", like Win32 SendMessage. If in the right context,
// call the handler directly.
Message msg;
msg.posted_from = posted_from;
msg.phandler = phandler;
msg.message_id = id;
msg.pdata = pdata;
if (IsCurrent()) {
#if RTC_DCHECK_IS_ON
RTC_DCHECK(this->IsInvokeToThreadAllowed(this));
RTC_DCHECK_RUN_ON(this);
could_be_blocking_call_count_++;
#endif
msg.phandler->OnMessage(&msg);
return;
}
AssertBlockingIsAllowedOnCurrentThread();
Thread* current_thread = Thread::Current();
#if RTC_DCHECK_IS_ON
if (current_thread) {
RTC_DCHECK_RUN_ON(current_thread);
current_thread->blocking_call_count_++;
RTC_DCHECK(current_thread->IsInvokeToThreadAllowed(this));
ThreadManager::Instance()->RegisterSendAndCheckForCycles(current_thread,
this);
}
#endif
// Perhaps down the line we can get rid of this workaround and always require
// current_thread to be valid when Send() is called.
std::unique_ptr<rtc::Event> done_event;
if (!current_thread)
done_event.reset(new rtc::Event());
bool ready = false;
PostTask(webrtc::ToQueuedTask(
[&msg]() mutable { msg.phandler->OnMessage(&msg); },
[this, &ready, current_thread, done = done_event.get()] {
if (current_thread) {
CritScope cs(&crit_);
ready = true;
current_thread->socketserver()->WakeUp();
} else {
done->Set();
}
}));
if (current_thread) {
bool waited = false;
crit_.Enter();
while (!ready) {
crit_.Leave();
current_thread->socketserver()->Wait(kForever, false);
waited = true;
crit_.Enter();
}
crit_.Leave();
// Our Wait loop above may have consumed some WakeUp events for this
// Thread, that weren't relevant to this Send. Losing these WakeUps can
// cause problems for some SocketServers.
//
// Concrete example:
// Win32SocketServer on thread A calls Send on thread B. While processing
// the message, thread B Posts a message to A. We consume the wakeup for
// that Post while waiting for the Send to complete, which means that when
// we exit this loop, we need to issue another WakeUp, or else the Posted
// message won't be processed in a timely manner.
if (waited) {
current_thread->socketserver()->WakeUp();
}
} else {
done_event->Wait(rtc::Event::kForever);
}
}
void Thread::InvokeInternal(const Location& posted_from,
rtc::FunctionView<void()> functor) {
TRACE_EVENT2("webrtc", "Thread::Invoke", "src_file", posted_from.file_name(),
"src_func", posted_from.function_name());
class FunctorMessageHandler : public MessageHandler {
public:
explicit FunctorMessageHandler(rtc::FunctionView<void()> functor)
: functor_(functor) {}
void OnMessage(Message* msg) override { functor_(); }
private:
rtc::FunctionView<void()> functor_;
} handler(functor);
Send(posted_from, &handler);
}
// Called by the ThreadManager when being set as the current thread.
void Thread::EnsureIsCurrentTaskQueue() {
task_queue_registration_ =
std::make_unique<TaskQueueBase::CurrentTaskQueueSetter>(this);
}
// Called by the ThreadManager when being set as the current thread.
void Thread::ClearCurrentTaskQueue() {
task_queue_registration_.reset();
}
void Thread::QueuedTaskHandler::OnMessage(Message* msg) {
RTC_DCHECK(msg);
auto* data = static_cast<ScopedMessageData<webrtc::QueuedTask>*>(msg->pdata);
std::unique_ptr<webrtc::QueuedTask> task(data->Release());
// Thread expects handler to own Message::pdata when OnMessage is called
// Since MessageData is no longer needed, delete it.
delete data;
// QueuedTask interface uses Run return value to communicate who owns the
// task. false means QueuedTask took the ownership.
if (!task->Run())
task.release();
}
void Thread::AllowInvokesToThread(Thread* thread) {
#if (!defined(NDEBUG) || RTC_DCHECK_IS_ON)
if (!IsCurrent()) {
PostTask(webrtc::ToQueuedTask(
[thread, this]() { AllowInvokesToThread(thread); }));
return;
}
RTC_DCHECK_RUN_ON(this);
allowed_threads_.push_back(thread);
invoke_policy_enabled_ = true;
#endif
}
void Thread::DisallowAllInvokes() {
#if (!defined(NDEBUG) || RTC_DCHECK_IS_ON)
if (!IsCurrent()) {
PostTask(webrtc::ToQueuedTask([this]() { DisallowAllInvokes(); }));
return;
}
RTC_DCHECK_RUN_ON(this);
allowed_threads_.clear();
invoke_policy_enabled_ = true;
#endif
}
#if RTC_DCHECK_IS_ON
uint32_t Thread::GetBlockingCallCount() const {
RTC_DCHECK_RUN_ON(this);
return blocking_call_count_;
}
uint32_t Thread::GetCouldBeBlockingCallCount() const {
RTC_DCHECK_RUN_ON(this);
return could_be_blocking_call_count_;
}
#endif
// Returns true if no policies added or if there is at least one policy
// that permits invocation to `target` thread.
bool Thread::IsInvokeToThreadAllowed(rtc::Thread* target) {
#if (!defined(NDEBUG) || RTC_DCHECK_IS_ON)
RTC_DCHECK_RUN_ON(this);
if (!invoke_policy_enabled_) {
return true;
}
for (const auto* thread : allowed_threads_) {
if (thread == target) {
return true;
}
}
return false;
#else
return true;
#endif
}
void Thread::PostTask(std::unique_ptr<webrtc::QueuedTask> task) {
// Though Post takes MessageData by raw pointer (last parameter), it still
// takes it with ownership.
Post(RTC_FROM_HERE, &queued_task_handler_,
/*id=*/0, new ScopedMessageData<webrtc::QueuedTask>(std::move(task)));
}
void Thread::PostDelayedTask(std::unique_ptr<webrtc::QueuedTask> task,
uint32_t milliseconds) {
// This implementation does not support low precision yet.
PostDelayedHighPrecisionTask(std::move(task), milliseconds);
}
void Thread::PostDelayedHighPrecisionTask(
std::unique_ptr<webrtc::QueuedTask> task,
uint32_t milliseconds) {
// Though PostDelayed takes MessageData by raw pointer (last parameter),
// it still takes it with ownership.
PostDelayed(RTC_FROM_HERE, milliseconds, &queued_task_handler_, /*id=*/0,
new ScopedMessageData<webrtc::QueuedTask>(std::move(task)));
}
void Thread::Delete() {
Stop();
delete this;
}
bool Thread::IsProcessingMessagesForTesting() {
return (owned_ || IsCurrent()) && !IsQuitting();
}
void Thread::Clear(MessageHandler* phandler,
uint32_t id,
MessageList* removed) {
CritScope cs(&crit_);
ClearInternal(phandler, id, removed);
}
bool Thread::ProcessMessages(int cmsLoop) {
// Using ProcessMessages with a custom clock for testing and a time greater
// than 0 doesn't work, since it's not guaranteed to advance the custom
// clock's time, and may get stuck in an infinite loop.
RTC_DCHECK(GetClockForTesting() == nullptr || cmsLoop == 0 ||
cmsLoop == kForever);
int64_t msEnd = (kForever == cmsLoop) ? 0 : TimeAfter(cmsLoop);
int cmsNext = cmsLoop;
while (true) {
#if defined(WEBRTC_MAC)
ScopedAutoReleasePool pool;
#endif
Message msg;
if (!Get(&msg, cmsNext))
return !IsQuitting();
Dispatch(&msg);
if (cmsLoop != kForever) {
cmsNext = static_cast<int>(TimeUntil(msEnd));
if (cmsNext < 0)
return true;
}
}
}
bool Thread::WrapCurrentWithThreadManager(ThreadManager* thread_manager,
bool need_synchronize_access) {
RTC_DCHECK(!IsRunning());
#if defined(WEBRTC_WIN)
if (need_synchronize_access) {
// We explicitly ask for no rights other than synchronization.
// This gives us the best chance of succeeding.
thread_ = OpenThread(SYNCHRONIZE, FALSE, GetCurrentThreadId());
if (!thread_) {
RTC_LOG_GLE(LS_ERROR) << "Unable to get handle to thread.";
return false;
}
thread_id_ = GetCurrentThreadId();
}
#elif defined(WEBRTC_POSIX)
thread_ = pthread_self();
#endif
owned_ = false;
thread_manager->SetCurrentThread(this);
return true;
}
bool Thread::IsRunning() {
#if defined(WEBRTC_WIN)
return thread_ != nullptr;
#elif defined(WEBRTC_POSIX)
return thread_ != 0;
#endif
}
// static
MessageHandler* Thread::GetPostTaskMessageHandler() {
// Allocate at first call, never deallocate.
static MessageHandler* handler = new MessageHandlerWithTask;
return handler;
}
AutoThread::AutoThread()
: Thread(CreateDefaultSocketServer(), /*do_init=*/false) {
if (!ThreadManager::Instance()->CurrentThread()) {
// DoInit registers with ThreadManager. Do that only if we intend to
// be rtc::Thread::Current(), otherwise ProcessAllMessageQueuesInternal will
// post a message to a queue that no running thread is serving.
DoInit();
ThreadManager::Instance()->SetCurrentThread(this);
}
}
AutoThread::~AutoThread() {
Stop();
DoDestroy();
if (ThreadManager::Instance()->CurrentThread() == this) {
ThreadManager::Instance()->SetCurrentThread(nullptr);
}
}
AutoSocketServerThread::AutoSocketServerThread(SocketServer* ss)
: Thread(ss, /*do_init=*/false) {
DoInit();
old_thread_ = ThreadManager::Instance()->CurrentThread();
// Temporarily set the current thread to nullptr so that we can keep checks
// around that catch unintentional pointer overwrites.
rtc::ThreadManager::Instance()->SetCurrentThread(nullptr);
rtc::ThreadManager::Instance()->SetCurrentThread(this);
if (old_thread_) {
ThreadManager::Remove(old_thread_);
}
}
AutoSocketServerThread::~AutoSocketServerThread() {
RTC_DCHECK(ThreadManager::Instance()->CurrentThread() == this);
// Stop and destroy the thread before clearing it as the current thread.
// Sometimes there are messages left in the Thread that will be
// destroyed by DoDestroy, and sometimes the destructors of the message and/or
// its contents rely on this thread still being set as the current thread.
Stop();
DoDestroy();
rtc::ThreadManager::Instance()->SetCurrentThread(nullptr);
rtc::ThreadManager::Instance()->SetCurrentThread(old_thread_);
if (old_thread_) {
ThreadManager::Add(old_thread_);
}
}
} // namespace rtc