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

webrtc/logging/rtc_event_log/rtc_event_log_helper_thread.h

-/*
- *  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.
- */
-
-#ifndef WEBRTC_LOGGING_RTC_EVENT_LOG_RTC_EVENT_LOG_HELPER_THREAD_H_
-#define WEBRTC_LOGGING_RTC_EVENT_LOG_RTC_EVENT_LOG_HELPER_THREAD_H_
-
-#include <deque>
-#include <limits>
-#include <memory>
-#include <utility>
-#include <vector>
-
-#include "webrtc/rtc_base/constructormagic.h"
-#include "webrtc/rtc_base/event.h"
-#include "webrtc/rtc_base/ignore_wundef.h"
-#include "webrtc/rtc_base/platform_thread.h"
-#include "webrtc/rtc_base/protobuf_utils.h"
-#include "webrtc/rtc_base/swap_queue.h"
-#include "webrtc/system_wrappers/include/file_wrapper.h"
-
-#ifdef ENABLE_RTC_EVENT_LOG
-// *.ph.h files are generated at build-time by the protobuf compiler.
-RTC_PUSH_IGNORING_WUNDEF()
-#ifdef WEBRTC_ANDROID_PLATFORM_BUILD
-#include "external/webrtc/webrtc/logging/rtc_event_log/rtc_event_log.pb.h"
-#else
-#include "webrtc/logging/rtc_event_log/rtc_event_log.pb.h"
-#endif
-RTC_POP_IGNORING_WUNDEF()
-#endif
-
-#ifdef ENABLE_RTC_EVENT_LOG
-
-namespace webrtc {
-
-class RtcEventLogHelperThread final {
- public:
-  struct ControlMessage {
-    ControlMessage()
-        : message_type(STOP_FILE),
-          file(nullptr),
-          max_size_bytes(0),
-          start_time(0),
-          stop_time(0) {}
-    enum { START_FILE, STOP_FILE, TERMINATE_THREAD } message_type;
-
-    std::unique_ptr<FileWrapper> file;  // Only used with START_FILE.
-    int64_t max_size_bytes;             // Only used with START_FILE.
-    int64_t start_time;                 // Only used with START_FILE.
-    int64_t stop_time;                  // Used with all 3 message types.
-
-    friend void swap(ControlMessage& lhs, ControlMessage& rhs) {
-      using std::swap;
-      swap(lhs.message_type, rhs.message_type);
-      lhs.file.swap(rhs.file);
-      swap(lhs.max_size_bytes, rhs.max_size_bytes);
-      swap(lhs.start_time, rhs.start_time);
-      swap(lhs.stop_time, rhs.stop_time);
-    }
-  };
-
-  RtcEventLogHelperThread(
-      SwapQueue<ControlMessage>* message_queue,
-      SwapQueue<std::unique_ptr<rtclog::Event>>* event_queue);
-  ~RtcEventLogHelperThread();
-
-  // This function MUST be called once a STOP_FILE message is added to the
-  // signalling queue. The function will make sure that the output thread
-  // wakes up to read the message, and it blocks until the output thread has
-  // finished writing to the file.
-  void WaitForFileFinished();
-
-  // This fuction MUST be called once an event is added to the event queue.
-  void SignalNewEvent();
-
- private:
-  static void ThreadOutputFunction(void* obj);
-
-  bool AppendEventToString(rtclog::Event* event);
-  bool LogToMemory();
-  void StartLogFile();
-  bool LogToFile();
-  void StopLogFile();
-  void ProcessEvents();
-
-  // Message queues for passing events to the logging thread.
-  SwapQueue<ControlMessage>* message_queue_;
-  SwapQueue<std::unique_ptr<rtclog::Event>>* event_queue_;
-
-  // History containing the most recent events (~ 10 s).
-  std::deque<std::unique_ptr<rtclog::Event>> history_;
-
-  // History containing all past configuration events.
-  std::vector<std::unique_ptr<rtclog::Event>> config_history_;
-
-  std::unique_ptr<FileWrapper> file_;
-  rtc::PlatformThread thread_;
-
-  int64_t max_size_bytes_;
-  int64_t written_bytes_;
-  int64_t start_time_;
-  int64_t stop_time_;
-
-  bool has_recent_event_;
-  std::unique_ptr<rtclog::Event> most_recent_event_;
-
-  // Temporary space for serializing profobuf data.
-  ProtoString output_string_;
-
-  rtc::Event wake_periodically_;
-  rtc::Event wake_from_hibernation_;
-  rtc::Event file_finished_;
-
-  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(RtcEventLogHelperThread);
-};
-
-}  // namespace webrtc
-
-#endif  // ENABLE_RTC_EVENT_LOG
-
-#endif  // WEBRTC_LOGGING_RTC_EVENT_LOG_RTC_EVENT_LOG_HELPER_THREAD_H_