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 #include "IdleTimer.h"
18
19 #include <chrono>
20 #include <thread>
21
22 namespace android {
23 namespace scheduler {
24
IdleTimer(const Interval & interval,const ResetCallback & resetCallback,const TimeoutCallback & timeoutCallback)25 IdleTimer::IdleTimer(const Interval& interval, const ResetCallback& resetCallback,
26 const TimeoutCallback& timeoutCallback)
27 : mInterval(interval), mResetCallback(resetCallback), mTimeoutCallback(timeoutCallback) {}
28
~IdleTimer()29 IdleTimer::~IdleTimer() {
30 stop();
31 }
32
start()33 void IdleTimer::start() {
34 {
35 std::lock_guard<std::mutex> lock(mMutex);
36 mState = TimerState::RESET;
37 }
38 mThread = std::thread(&IdleTimer::loop, this);
39 }
40
stop()41 void IdleTimer::stop() {
42 {
43 std::lock_guard<std::mutex> lock(mMutex);
44 mState = TimerState::STOPPED;
45 }
46 mCondition.notify_all();
47 if (mThread.joinable()) {
48 mThread.join();
49 }
50 }
51
loop()52 void IdleTimer::loop() {
53 while (true) {
54 bool triggerReset = false;
55 bool triggerTimeout = false;
56 {
57 std::lock_guard<std::mutex> lock(mMutex);
58 if (mState == TimerState::STOPPED) {
59 break;
60 }
61
62 if (mState == TimerState::IDLE) {
63 mCondition.wait(mMutex);
64 continue;
65 }
66
67 if (mState == TimerState::RESET) {
68 triggerReset = true;
69 }
70 }
71 if (triggerReset && mResetCallback) {
72 mResetCallback();
73 }
74
75 { // lock the mutex again. someone might have called stop meanwhile
76 std::lock_guard<std::mutex> lock(mMutex);
77 if (mState == TimerState::STOPPED) {
78 break;
79 }
80
81 auto triggerTime = std::chrono::steady_clock::now() + mInterval;
82 mState = TimerState::WAITING;
83 while (mState == TimerState::WAITING) {
84 constexpr auto zero = std::chrono::steady_clock::duration::zero();
85 auto waitTime = triggerTime - std::chrono::steady_clock::now();
86 if (waitTime > zero) mCondition.wait_for(mMutex, waitTime);
87 if (mState == TimerState::RESET) {
88 triggerTime = std::chrono::steady_clock::now() + mInterval;
89 mState = TimerState::WAITING;
90 } else if (mState == TimerState::WAITING &&
91 (triggerTime - std::chrono::steady_clock::now()) <= zero) {
92 triggerTimeout = true;
93 mState = TimerState::IDLE;
94 }
95 }
96 }
97 if (triggerTimeout && mTimeoutCallback) {
98 mTimeoutCallback();
99 }
100 }
101 } // namespace scheduler
102
reset()103 void IdleTimer::reset() {
104 {
105 std::lock_guard<std::mutex> lock(mMutex);
106 mState = TimerState::RESET;
107 }
108 mCondition.notify_all();
109 }
110
111 } // namespace scheduler
112 } // namespace android
113