Reland of Make RtcEventLogImpl to use a TaskQueue instead of a helper-thread

webrtc/logging/rtc_event_log/rtc_event_log_helper_thread.cc

Index: webrtc/logging/rtc_event_log/rtc_event_log_helper_thread.cc
diff --git a/webrtc/logging/rtc_event_log/rtc_event_log_helper_thread.cc b/webrtc/logging/rtc_event_log/rtc_event_log_helper_thread.cc
deleted file mode 100644
index a98336fa521ff06eac2225614f0991fa29f1c810..0000000000000000000000000000000000000000
--- a/webrtc/logging/rtc_event_log/rtc_event_log_helper_thread.cc
+++ /dev/null
@@ -1,315 +0,0 @@
-/*
- *  Copyright (c) 2016 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 "webrtc/logging/rtc_event_log/rtc_event_log_helper_thread.h"
-
-#include <algorithm>
-
-#include "webrtc/rtc_base/checks.h"
-#include "webrtc/rtc_base/logging.h"
-#include "webrtc/rtc_base/timeutils.h"
-
-#ifdef ENABLE_RTC_EVENT_LOG
-
-namespace webrtc {
-
-namespace {
-const int kEventsInHistory = 10000;
-
-bool IsConfigEvent(const rtclog::Event& event) {
-  rtclog::Event_EventType event_type = event.type();
-  return event_type == rtclog::Event::VIDEO_RECEIVER_CONFIG_EVENT ||
-         event_type == rtclog::Event::VIDEO_SENDER_CONFIG_EVENT ||
-         event_type == rtclog::Event::AUDIO_RECEIVER_CONFIG_EVENT ||
-         event_type == rtclog::Event::AUDIO_SENDER_CONFIG_EVENT;
-}
-}  // namespace
-
-// RtcEventLogImpl member functions.
-RtcEventLogHelperThread::RtcEventLogHelperThread(
-    SwapQueue<ControlMessage>* message_queue,
-    SwapQueue<std::unique_ptr<rtclog::Event>>* event_queue)
-    : message_queue_(message_queue),
-      event_queue_(event_queue),
-      file_(FileWrapper::Create()),
-      thread_(&ThreadOutputFunction, this, "RtcEventLog thread"),
-      max_size_bytes_(std::numeric_limits<int64_t>::max()),
-      written_bytes_(0),
-      start_time_(0),
-      stop_time_(std::numeric_limits<int64_t>::max()),
-      has_recent_event_(false),
-      wake_periodically_(false, false),
-      wake_from_hibernation_(false, false),
-      file_finished_(false, false) {
-  RTC_DCHECK(message_queue_);
-  RTC_DCHECK(event_queue_);
-  thread_.Start();
-}
-
-RtcEventLogHelperThread::~RtcEventLogHelperThread() {
-  ControlMessage message;
-  message.message_type = ControlMessage::TERMINATE_THREAD;
-  message.stop_time = rtc::TimeMicros();
-  while (!message_queue_->Insert(&message)) {
-    // We can't destroy the event log until we have stopped the thread,
-    // so clear the message queue and try again. Note that if we clear
-    // any STOP_FILE events, then the threads calling StopLogging would likely
-    // wait indefinitely. However, there should not be any such calls as we
-    // are executing the destructor.
-    LOG(LS_WARNING) << "Clearing message queue to terminate thread.";
-    message_queue_->Clear();
-  }
-  wake_from_hibernation_.Set();
-  wake_periodically_.Set();  // Wake up the output thread.
-  thread_.Stop();            // Wait for the thread to terminate.
-}
-
-void RtcEventLogHelperThread::WaitForFileFinished() {
-  wake_from_hibernation_.Set();
-  wake_periodically_.Set();
-  file_finished_.Wait(rtc::Event::kForever);
-}
-
-void RtcEventLogHelperThread::SignalNewEvent() {
-  wake_from_hibernation_.Set();
-}
-
-bool RtcEventLogHelperThread::AppendEventToString(rtclog::Event* event) {
-  rtclog::EventStream event_stream;
-  event_stream.add_stream();
-  event_stream.mutable_stream(0)->Swap(event);
-  // We create a new event stream per event but because of the way protobufs
-  // are encoded, events can be merged by concatenating them. Therefore,
-  // it will look like a single stream when we read it back from file.
-  bool stop = true;
-  if (written_bytes_ + static_cast<int64_t>(output_string_.size()) +
-          event_stream.ByteSize() <=
-      max_size_bytes_) {
-    event_stream.AppendToString(&output_string_);
-    stop = false;
-  }
-  // Swap the event back so that we don't mix event types in the queues.
-  event_stream.mutable_stream(0)->Swap(event);
-  return stop;
-}
-
-bool RtcEventLogHelperThread::LogToMemory() {
-  RTC_DCHECK(!file_->is_open());
-  bool message_received = false;
-
-  // Process each event earlier than the current time and append it to the
-  // appropriate history_.
-  int64_t current_time = rtc::TimeMicros();
-  if (!has_recent_event_) {
-    has_recent_event_ = event_queue_->Remove(&most_recent_event_);
-  }
-  while (has_recent_event_ &&
-         most_recent_event_->timestamp_us() <= current_time) {
-    if (IsConfigEvent(*most_recent_event_)) {
-      config_history_.push_back(std::move(most_recent_event_));
-    } else {
-      history_.push_back(std::move(most_recent_event_));
-      if (history_.size() > kEventsInHistory)
-        history_.pop_front();
-    }
-    has_recent_event_ = event_queue_->Remove(&most_recent_event_);
-    message_received = true;
-  }
-  return message_received;
-}
-
-void RtcEventLogHelperThread::StartLogFile() {
-  RTC_DCHECK(file_->is_open());
-  bool stop = false;
-  output_string_.clear();
-
-  // Create and serialize the LOG_START event.
-  rtclog::Event start_event;
-  start_event.set_timestamp_us(start_time_);
-  start_event.set_type(rtclog::Event::LOG_START);
-  AppendEventToString(&start_event);
-
-  // Serialize the config information for all old streams.
-  for (auto& event : config_history_) {
-    AppendEventToString(event.get());
-  }
-
-  // Serialize the events in the event queue.
-  while (!history_.empty() && !stop) {
-    stop = AppendEventToString(history_.front().get());
-    if (!stop) {
-      history_.pop_front();
-    }
-  }
-
-  // Write to file.
-  if (!file_->Write(output_string_.data(), output_string_.size())) {
-    LOG(LS_ERROR) << "FileWrapper failed to write WebRtcEventLog file.";
-    // The current FileWrapper implementation closes the file on error.
-    RTC_DCHECK(!file_->is_open());
-    return;
-  }
-  written_bytes_ += output_string_.size();
-
-  // Free the allocated memory since we probably won't need this amount of
-  // space again.
-  output_string_.clear();
-  output_string_.shrink_to_fit();
-
-  if (stop) {
-    RTC_DCHECK(file_->is_open());
-    StopLogFile();
-  }
-}
-
-bool RtcEventLogHelperThread::LogToFile() {
-  RTC_DCHECK(file_->is_open());
-  output_string_.clear();
-  bool message_received = false;
-
-  // Append each event older than both the current time and the stop time
-  // to the output_string_.
-  int64_t current_time = rtc::TimeMicros();
-  int64_t time_limit = std::min(current_time, stop_time_);
-  if (!has_recent_event_) {
-    has_recent_event_ = event_queue_->Remove(&most_recent_event_);
-  }
-  bool stop = false;
-  while (!stop && has_recent_event_ &&
-         most_recent_event_->timestamp_us() <= time_limit) {
-    stop = AppendEventToString(most_recent_event_.get());
-    if (!stop) {
-      if (IsConfigEvent(*most_recent_event_)) {
-        config_history_.push_back(std::move(most_recent_event_));
-      }
-      has_recent_event_ = event_queue_->Remove(&most_recent_event_);
-    }
-    message_received = true;
-  }
-
-  // Write string to file.
-  if (!file_->Write(output_string_.data(), output_string_.size())) {
-    LOG(LS_ERROR) << "FileWrapper failed to write WebRtcEventLog file.";
-    // The current FileWrapper implementation closes the file on error.
-    RTC_DCHECK(!file_->is_open());
-    return message_received;
-  }
-  written_bytes_ += output_string_.size();
-
-  // We want to stop logging if we have reached the file size limit. We also
-  // want to stop logging if the remaining events are more recent than the
-  // time limit, or in other words if we have terminated the loop despite
-  // having more events in the queue.
-  if ((has_recent_event_ && most_recent_event_->timestamp_us() > stop_time_) ||
-      stop) {
-    RTC_DCHECK(file_->is_open());
-    StopLogFile();
-  }
-  return message_received;
-}
-
-void RtcEventLogHelperThread::StopLogFile() {
-  RTC_DCHECK(file_->is_open());
-  output_string_.clear();
-
-  rtclog::Event end_event;
-  // This function can be called either because we have reached the stop time,
-  // or because we have reached the log file size limit. Therefore, use the
-  // current time if we have not reached the time limit.
-  end_event.set_timestamp_us(
-      std::min(stop_time_, rtc::TimeMicros()));
-  end_event.set_type(rtclog::Event::LOG_END);
-  AppendEventToString(&end_event);
-
-  if (written_bytes_ + static_cast<int64_t>(output_string_.size()) <=
-      max_size_bytes_) {
-    if (!file_->Write(output_string_.data(), output_string_.size())) {
-      LOG(LS_ERROR) << "FileWrapper failed to write WebRtcEventLog file.";
-      // The current FileWrapper implementation closes the file on error.
-      RTC_DCHECK(!file_->is_open());
-    }
-    written_bytes_ += output_string_.size();
-  }
-
-  max_size_bytes_ = std::numeric_limits<int64_t>::max();
-  written_bytes_ = 0;
-  start_time_ = 0;
-  stop_time_ = std::numeric_limits<int64_t>::max();
-  output_string_.clear();
-  file_->CloseFile();
-  RTC_DCHECK(!file_->is_open());
-}
-
-void RtcEventLogHelperThread::ProcessEvents() {
-  ControlMessage message;
-
-  while (true) {
-    bool message_received = false;
-    // Process control messages.
-    while (message_queue_->Remove(&message)) {
-      switch (message.message_type) {
-        case ControlMessage::START_FILE:
-          if (!file_->is_open()) {
-            max_size_bytes_ = message.max_size_bytes;
-            start_time_ = message.start_time;
-            stop_time_ = message.stop_time;
-            file_.swap(message.file);
-            StartLogFile();
-          } else {
-            // Already started. Ignore message and close file handle.
-            message.file->CloseFile();
-          }
-          message_received = true;
-          break;
-        case ControlMessage::STOP_FILE:
-          if (file_->is_open()) {
-            stop_time_ = message.stop_time;
-            LogToFile();  // Log remaining events from message queues.
-          }
-          // LogToFile might stop on it's own so we need to recheck the state.
-          if (file_->is_open()) {
-            StopLogFile();
-          }
-          file_finished_.Set();
-          message_received = true;
-          break;
-        case ControlMessage::TERMINATE_THREAD:
-          if (file_->is_open()) {
-            StopLogFile();
-          }
-          return;
-      }
-    }
-
-    // Write events to file or memory.
-    if (file_->is_open()) {
-      message_received |= LogToFile();
-    } else {
-      message_received |= LogToMemory();
-    }
-
-    // Accumulate a new batch of events instead of processing them one at a
-    // time.
-    if (message_received) {
-      wake_periodically_.Wait(100);
-    } else {
-      wake_from_hibernation_.Wait(rtc::Event::kForever);
-    }
-  }
-}
-
-void RtcEventLogHelperThread::ThreadOutputFunction(void* obj) {
-  RtcEventLogHelperThread* helper = static_cast<RtcEventLogHelperThread*>(obj);
-  helper->ProcessEvents();
-}
-
-}  // namespace webrtc
-
-#endif  // ENABLE_RTC_EVENT_LOG