1 /*
2 * Copyright (C) 2020 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 <chrono>
18 #include <thread>
19
20 #include <vibratorservice/VibratorCallbackScheduler.h>
21
22 namespace android {
23
24 namespace vibrator {
25
26 // -------------------------------------------------------------------------------------------------
27
isExpired() const28 bool DelayedCallback::isExpired() const {
29 return mExpiration <= std::chrono::steady_clock::now();
30 }
31
getExpiration() const32 DelayedCallback::Timestamp DelayedCallback::getExpiration() const {
33 return mExpiration;
34 }
35
run() const36 void DelayedCallback::run() const {
37 mCallback();
38 }
39
operator <(const DelayedCallback & other) const40 bool DelayedCallback::operator<(const DelayedCallback& other) const {
41 return mExpiration < other.mExpiration;
42 }
43
operator >(const DelayedCallback & other) const44 bool DelayedCallback::operator>(const DelayedCallback& other) const {
45 return mExpiration > other.mExpiration;
46 }
47
48 // -------------------------------------------------------------------------------------------------
49
~CallbackScheduler()50 CallbackScheduler::~CallbackScheduler() {
51 {
52 std::lock_guard<std::mutex> lock(mMutex);
53 mFinished = true;
54 }
55 mCondition.notify_all();
56 if (mCallbackThread && mCallbackThread->joinable()) {
57 mCallbackThread->join();
58 }
59 }
60
schedule(std::function<void ()> callback,std::chrono::milliseconds delay)61 void CallbackScheduler::schedule(std::function<void()> callback, std::chrono::milliseconds delay) {
62 {
63 std::lock_guard<std::mutex> lock(mMutex);
64 if (mCallbackThread == nullptr) {
65 mCallbackThread = std::make_unique<std::thread>(&CallbackScheduler::loop, this);
66 }
67 mQueue.emplace(DelayedCallback(callback, delay));
68 }
69 mCondition.notify_all();
70 }
71
loop()72 void CallbackScheduler::loop() {
73 while (true) {
74 std::unique_lock<std::mutex> lock(mMutex);
75 if (mFinished) {
76 // Destructor was called, so let the callback thread die.
77 break;
78 }
79 while (!mQueue.empty() && mQueue.top().isExpired()) {
80 DelayedCallback callback = mQueue.top();
81 mQueue.pop();
82 lock.unlock();
83 callback.run();
84 lock.lock();
85 }
86 if (mQueue.empty()) {
87 // Wait until a new callback is scheduled.
88 mCondition.wait(mMutex);
89 } else {
90 // Wait until next callback expires, or a new one is scheduled.
91 mCondition.wait_until(mMutex, mQueue.top().getExpiration());
92 }
93 }
94 }
95
96 // -------------------------------------------------------------------------------------------------
97
98 }; // namespace vibrator
99
100 }; // namespace android
101