1 /* 2 * Copyright 2004 The WebRTC Project Authors. All rights reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef WEBRTC_BASE_TASKRUNNER_H__ 12 #define WEBRTC_BASE_TASKRUNNER_H__ 13 14 #include <vector> 15 16 #include "webrtc/base/basictypes.h" 17 #include "webrtc/base/sigslot.h" 18 #include "webrtc/base/taskparent.h" 19 20 namespace rtc { 21 class Task; 22 23 const int64_t kSecToMsec = 1000; 24 const int64_t kMsecTo100ns = 10000; 25 const int64_t kSecTo100ns = kSecToMsec * kMsecTo100ns; 26 27 class TaskRunner : public TaskParent, public sigslot::has_slots<> { 28 public: 29 TaskRunner(); 30 ~TaskRunner() override; 31 32 virtual void WakeTasks() = 0; 33 34 // Returns the current time in 100ns units. It is used for 35 // determining timeouts. The origin is not important, only 36 // the units and that rollover while the computer is running. 37 // 38 // On Windows, GetSystemTimeAsFileTime is the typical implementation. 39 virtual int64_t CurrentTime() = 0; 40 41 void StartTask(Task *task); 42 void RunTasks(); 43 void PollTasks(); 44 45 void UpdateTaskTimeout(Task* task, int64_t previous_task_timeout_time); 46 47 #if !defined(NDEBUG) is_ok_to_delete(Task * task)48 bool is_ok_to_delete(Task* task) { 49 return task == deleting_task_; 50 } 51 IncrementAbortCount()52 void IncrementAbortCount() { 53 ++abort_count_; 54 } 55 DecrementAbortCount()56 void DecrementAbortCount() { 57 --abort_count_; 58 } 59 #endif 60 61 // Returns the next absolute time when a task times out 62 // OR "0" if there is no next timeout. 63 int64_t next_task_timeout() const; 64 65 protected: 66 // The primary usage of this method is to know if 67 // a callback timer needs to be set-up or adjusted. 68 // This method will be called 69 // * when the next_task_timeout() becomes a smaller value OR 70 // * when next_task_timeout() has changed values and the previous 71 // value is in the past. 72 // 73 // If the next_task_timeout moves to the future, this method will *not* 74 // get called (because it subclass should check next_task_timeout() 75 // when its timer goes off up to see if it needs to set-up a new timer). 76 // 77 // Note that this maybe called conservatively. In that it may be 78 // called when no time change has happened. OnTimeoutChange()79 virtual void OnTimeoutChange() { 80 // by default, do nothing. 81 } 82 83 private: 84 void InternalRunTasks(bool in_destructor); 85 void CheckForTimeoutChange(int64_t previous_timeout_time); 86 87 std::vector<Task *> tasks_; 88 Task *next_timeout_task_; 89 bool tasks_running_; 90 #if !defined(NDEBUG) 91 int abort_count_; 92 Task* deleting_task_; 93 #endif 94 95 void RecalcNextTimeout(Task *exclude_task); 96 }; 97 98 } // namespace rtc 99 100 #endif // TASK_BASE_TASKRUNNER_H__ 101