| /* |
| * 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/message_queue.h" |
| |
| #include <string> |
| #include <utility> |
| |
| #include "absl/algorithm/container.h" |
| #include "rtc_base/atomic_ops.h" |
| #include "rtc_base/checks.h" |
| #include "rtc_base/logging.h" |
| #include "rtc_base/thread.h" |
| #include "rtc_base/time_utils.h" |
| #include "rtc_base/trace_event.h" |
| |
| namespace rtc { |
| namespace { |
| |
| const int kMaxMsgLatency = 150; // 150 ms |
| const int kSlowDispatchLoggingThreshold = 50; // 50 ms |
| |
| class RTC_SCOPED_LOCKABLE MarkProcessingCritScope { |
| public: |
| MarkProcessingCritScope(const CriticalSection* 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(); |
| } |
| |
| private: |
| const CriticalSection* const cs_; |
| size_t* processing_; |
| |
| RTC_DISALLOW_COPY_AND_ASSIGN(MarkProcessingCritScope); |
| }; |
| } // namespace |
| |
| //------------------------------------------------------------------ |
| // MessageQueueManager |
| |
| MessageQueueManager* MessageQueueManager::Instance() { |
| static MessageQueueManager* const instance = new MessageQueueManager; |
| return instance; |
| } |
| |
| MessageQueueManager::MessageQueueManager() : processing_(0) {} |
| |
| MessageQueueManager::~MessageQueueManager() {} |
| |
| void MessageQueueManager::Add(MessageQueue* message_queue) { |
| return Instance()->AddInternal(message_queue); |
| } |
| void MessageQueueManager::AddInternal(MessageQueue* 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); |
| } |
| |
| void MessageQueueManager::Remove(MessageQueue* message_queue) { |
| return Instance()->RemoveInternal(message_queue); |
| } |
| void MessageQueueManager::RemoveInternal(MessageQueue* message_queue) { |
| { |
| CritScope cs(&crit_); |
| // Prevent changes while the list of message queues is processed. |
| RTC_DCHECK_EQ(processing_, 0); |
| std::vector<MessageQueue*>::iterator iter; |
| iter = absl::c_find(message_queues_, message_queue); |
| if (iter != message_queues_.end()) { |
| message_queues_.erase(iter); |
| } |
| } |
| } |
| |
| void MessageQueueManager::Clear(MessageHandler* handler) { |
| return Instance()->ClearInternal(handler); |
| } |
| void MessageQueueManager::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 (MessageQueue* queue : message_queues_) { |
| queue->Clear(handler); |
| } |
| } |
| |
| void MessageQueueManager::ProcessAllMessageQueuesForTesting() { |
| return Instance()->ProcessAllMessageQueuesInternal(); |
| } |
| |
| void MessageQueueManager::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. |
| volatile 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(volatile int* value) : value_(value) { |
| AtomicOps::Increment(value_); |
| } |
| ~ScopedIncrement() override { AtomicOps::Decrement(value_); } |
| |
| private: |
| volatile int* value_; |
| }; |
| |
| { |
| MarkProcessingCritScope cs(&crit_, &processing_); |
| for (MessageQueue* 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 (AtomicOps::AcquireLoad(&queues_not_done) > 0) { |
| if (current) { |
| current->ProcessMessages(0); |
| } |
| } |
| } |
| |
| //------------------------------------------------------------------ |
| // MessageQueue |
| MessageQueue::MessageQueue(SocketServer* ss, bool init_queue) |
| : fPeekKeep_(false), |
| dmsgq_next_num_(0), |
| fInitialized_(false), |
| fDestroyed_(false), |
| stop_(0), |
| ss_(ss) { |
| RTC_DCHECK(ss); |
| // Currently, MessageQueue holds a socket server, and is the base class for |
| // Thread. It seems like it makes more sense for Thread to hold the socket |
| // server, and provide it to the MessageQueue, since the Thread controls |
| // the I/O model, and MQ is agnostic to those details. Anyway, this causes |
| // messagequeue_unittest to depend on network libraries... yuck. |
| ss_->SetMessageQueue(this); |
| if (init_queue) { |
| DoInit(); |
| } |
| } |
| |
| MessageQueue::MessageQueue(std::unique_ptr<SocketServer> ss, bool init_queue) |
| : MessageQueue(ss.get(), init_queue) { |
| own_ss_ = std::move(ss); |
| } |
| |
| MessageQueue::~MessageQueue() { |
| DoDestroy(); |
| } |
| |
| void MessageQueue::DoInit() { |
| if (fInitialized_) { |
| return; |
| } |
| |
| fInitialized_ = true; |
| MessageQueueManager::Add(this); |
| } |
| |
| void MessageQueue::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. |
| SignalQueueDestroyed(); |
| MessageQueueManager::Remove(this); |
| ClearInternal(nullptr, MQID_ANY, nullptr); |
| |
| if (ss_) { |
| ss_->SetMessageQueue(nullptr); |
| } |
| } |
| |
| SocketServer* MessageQueue::socketserver() { |
| return ss_; |
| } |
| |
| void MessageQueue::WakeUpSocketServer() { |
| ss_->WakeUp(); |
| } |
| |
| void MessageQueue::Quit() { |
| AtomicOps::ReleaseStore(&stop_, 1); |
| WakeUpSocketServer(); |
| } |
| |
| bool MessageQueue::IsQuitting() { |
| return AtomicOps::AcquireLoad(&stop_) != 0; |
| } |
| |
| bool MessageQueue::IsProcessingMessagesForTesting() { |
| return !IsQuitting(); |
| } |
| |
| void MessageQueue::Restart() { |
| AtomicOps::ReleaseStore(&stop_, 0); |
| } |
| |
| bool MessageQueue::Peek(Message* pmsg, int cmsWait) { |
| if (fPeekKeep_) { |
| *pmsg = msgPeek_; |
| return true; |
| } |
| if (!Get(pmsg, cmsWait)) |
| return false; |
| msgPeek_ = *pmsg; |
| fPeekKeep_ = true; |
| return true; |
| } |
| |
| bool MessageQueue::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 sent messages |
| ReceiveSends(); |
| |
| // 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 (!dmsgq_.empty()) { |
| if (msCurrent < dmsgq_.top().msTrigger_) { |
| cmsDelayNext = TimeDiff(dmsgq_.top().msTrigger_, msCurrent); |
| break; |
| } |
| msgq_.push_back(dmsgq_.top().msg_); |
| dmsgq_.pop(); |
| } |
| } |
| // Pull a message off the message queue, if available. |
| if (msgq_.empty()) { |
| break; |
| } else { |
| *pmsg = msgq_.front(); |
| msgq_.pop_front(); |
| } |
| } // crit_ is released here. |
| |
| // Log a warning for time-sensitive messages that we're late to deliver. |
| if (pmsg->ts_sensitive) { |
| int64_t delay = TimeDiff(msCurrent, pmsg->ts_sensitive); |
| if (delay > 0) { |
| RTC_LOG_F(LS_WARNING) |
| << "id: " << pmsg->message_id |
| << " delay: " << (delay + kMaxMsgLatency) << "ms"; |
| } |
| } |
| // 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 MessageQueue::ReceiveSends() {} |
| |
| void MessageQueue::Post(const Location& posted_from, |
| MessageHandler* phandler, |
| uint32_t id, |
| MessageData* pdata, |
| bool 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; |
| if (time_sensitive) { |
| msg.ts_sensitive = TimeMillis() + kMaxMsgLatency; |
| } |
| msgq_.push_back(msg); |
| } |
| WakeUpSocketServer(); |
| } |
| |
| void MessageQueue::PostDelayed(const Location& posted_from, |
| int cmsDelay, |
| MessageHandler* phandler, |
| uint32_t id, |
| MessageData* pdata) { |
| return DoDelayPost(posted_from, cmsDelay, TimeAfter(cmsDelay), phandler, id, |
| pdata); |
| } |
| |
| void MessageQueue::PostAt(const Location& posted_from, |
| uint32_t tstamp, |
| MessageHandler* phandler, |
| uint32_t id, |
| MessageData* pdata) { |
| // This should work even if it is used (unexpectedly). |
| int64_t delay = static_cast<uint32_t>(TimeMillis()) - tstamp; |
| return DoDelayPost(posted_from, delay, tstamp, phandler, id, pdata); |
| } |
| |
| void MessageQueue::PostAt(const Location& posted_from, |
| int64_t tstamp, |
| MessageHandler* phandler, |
| uint32_t id, |
| MessageData* pdata) { |
| return DoDelayPost(posted_from, TimeUntil(tstamp), tstamp, phandler, id, |
| pdata); |
| } |
| |
| void MessageQueue::DoDelayPost(const Location& posted_from, |
| int64_t cmsDelay, |
| int64_t tstamp, |
| 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 dmsg(cmsDelay, tstamp, dmsgq_next_num_, msg); |
| dmsgq_.push(dmsg); |
| // 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. |
| ++dmsgq_next_num_; |
| RTC_DCHECK_NE(0, dmsgq_next_num_); |
| } |
| WakeUpSocketServer(); |
| } |
| |
| int MessageQueue::GetDelay() { |
| CritScope cs(&crit_); |
| |
| if (!msgq_.empty()) |
| return 0; |
| |
| if (!dmsgq_.empty()) { |
| int delay = TimeUntil(dmsgq_.top().msTrigger_); |
| if (delay < 0) |
| delay = 0; |
| return delay; |
| } |
| |
| return kForever; |
| } |
| |
| void MessageQueue::Clear(MessageHandler* phandler, |
| uint32_t id, |
| MessageList* removed) { |
| CritScope cs(&crit_); |
| ClearInternal(phandler, id, removed); |
| } |
| |
| void MessageQueue::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 (MessageList::iterator it = msgq_.begin(); it != msgq_.end();) { |
| if (it->Match(phandler, id)) { |
| if (removed) { |
| removed->push_back(*it); |
| } else { |
| delete it->pdata; |
| } |
| it = msgq_.erase(it); |
| } else { |
| ++it; |
| } |
| } |
| |
| // Remove from priority queue. Not directly iterable, so use this approach |
| |
| PriorityQueue::container_type::iterator new_end = dmsgq_.container().begin(); |
| for (PriorityQueue::container_type::iterator it = new_end; |
| it != dmsgq_.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; |
| } |
| } |
| dmsgq_.container().erase(new_end, dmsgq_.container().end()); |
| dmsgq_.reheap(); |
| } |
| |
| void MessageQueue::Dispatch(Message* pmsg) { |
| TRACE_EVENT2("webrtc", "MessageQueue::Dispatch", "src_file_and_line", |
| pmsg->posted_from.file_and_line(), "src_func", |
| pmsg->posted_from.function_name()); |
| int64_t start_time = TimeMillis(); |
| pmsg->phandler->OnMessage(pmsg); |
| int64_t end_time = TimeMillis(); |
| int64_t diff = TimeDiff(end_time, start_time); |
| if (diff >= kSlowDispatchLoggingThreshold) { |
| RTC_LOG(LS_INFO) << "Message took " << diff |
| << "ms to dispatch. Posted from: " |
| << pmsg->posted_from.ToString(); |
| } |
| } |
| |
| } // namespace rtc |