Revert 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
new file mode 100644
index 0000000000000000000000000000000000000000..a98336fa521ff06eac2225614f0991fa29f1c810
--- /dev/null
+++ b/webrtc/logging/rtc_event_log/rtc_event_log_helper_thread.cc
@@ -0,0 +1,315 @@
+/*
+ *  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