1 /* 2 * Copyright 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #pragma once 18 19 #include <base/bind.h> 20 #include <base/cancelable_callback.h> 21 #include <base/location.h> 22 #include <base/time/time.h> 23 24 #include <future> 25 26 namespace bluetooth { 27 28 namespace common { 29 30 class MessageLoopThread; 31 32 /** 33 * An alarm clock that posts a delayed task to a specified MessageLoopThread 34 * periodically. 35 * 36 * Warning: MessageLoopThread must be running when any task is scheduled or 37 * being executed 38 */ 39 class RepeatingTimer final { 40 public: RepeatingTimer()41 RepeatingTimer() : expected_time_next_task_us_(0) {} 42 RepeatingTimer(const RepeatingTimer&) = delete; 43 RepeatingTimer& operator=(const RepeatingTimer&) = delete; 44 45 ~RepeatingTimer(); 46 47 /** 48 * Schedule a delayed periodic task to the MessageLoopThread. Only one task 49 * can be scheduled at a time. If another task is scheduled, it will cancel 50 * the previous task synchronously and schedule the new periodic task; this 51 * blocks until the previous task is cancelled. 52 * 53 * @param thread thread to run the task 54 * @param from_here location where this task is originated 55 * @param task task created through base::Bind() 56 * @param period period for the task to be executed 57 * @return true iff task is scheduled successfully 58 */ 59 bool SchedulePeriodic(const base::WeakPtr<MessageLoopThread>& thread, 60 const base::Location& from_here, 61 base::RepeatingClosure task, base::TimeDelta period); 62 63 /** 64 * Post an event which cancels the current task asynchronously 65 */ 66 void Cancel(); 67 68 /** 69 * Post an event which cancels the current task and wait for the cancellation 70 * to be completed 71 */ 72 void CancelAndWait(); 73 74 /** 75 * Returns true when there is a pending task scheduled on a running thread, 76 * otherwise false. 77 */ 78 bool IsScheduled() const; 79 80 private: 81 base::WeakPtr<MessageLoopThread> message_loop_thread_; 82 base::CancelableClosure task_wrapper_; 83 base::RepeatingClosure task_; 84 base::TimeDelta period_; 85 uint64_t expected_time_next_task_us_; // Using clock boot time in time_util.h 86 mutable std::recursive_mutex api_mutex_; 87 void CancelHelper(std::promise<void> promise); 88 void CancelClosure(std::promise<void> promise); 89 90 void RunTask(); 91 }; 92 93 } // namespace common 94 95 } // namespace bluetooth 96