1 /*
2 * Copyright (C) 2017 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 #define LOG_TAG "WorkerThread"
18 //#define LOG_NDEBUG 0
19
20 #include <broadcastradio-utils/WorkerThread.h>
21
22 #include <log/log.h>
23
24 namespace android {
25
26 using std::chrono::milliseconds;
27 using std::chrono::steady_clock;
28 using std::function;
29 using std::lock_guard;
30 using std::mutex;
31 using std::priority_queue;
32 using std::this_thread::sleep_for;
33 using std::unique_lock;
34
operator <(const WorkerThread::Task & lhs,const WorkerThread::Task & rhs)35 bool operator<(const WorkerThread::Task& lhs, const WorkerThread::Task& rhs) {
36 return lhs.when > rhs.when;
37 }
38
WorkerThread()39 WorkerThread::WorkerThread() : mIsTerminating(false), mThread(&WorkerThread::threadLoop, this) {}
40
~WorkerThread()41 WorkerThread::~WorkerThread() {
42 ALOGV("%s", __func__);
43 {
44 lock_guard<mutex> lk(mMut);
45 mIsTerminating = true;
46 mCond.notify_one();
47 }
48 mThread.join();
49 }
50
schedule(function<void ()> task,milliseconds delay)51 void WorkerThread::schedule(function<void()> task, milliseconds delay) {
52 ALOGV("%s", __func__);
53
54 auto when = steady_clock::now() + delay;
55
56 lock_guard<mutex> lk(mMut);
57 mTasks.push(Task({when, task}));
58 mCond.notify_one();
59 }
60
cancelAll()61 void WorkerThread::cancelAll() {
62 ALOGV("%s", __func__);
63
64 lock_guard<mutex> lk(mMut);
65 priority_queue<Task>().swap(mTasks); // empty queue
66 }
67
threadLoop()68 void WorkerThread::threadLoop() {
69 ALOGV("%s", __func__);
70 while (!mIsTerminating) {
71 unique_lock<mutex> lk(mMut);
72 if (mTasks.empty()) {
73 mCond.wait(lk);
74 continue;
75 }
76
77 auto task = mTasks.top();
78 if (task.when > steady_clock::now()) {
79 mCond.wait_until(lk, task.when);
80 continue;
81 }
82
83 mTasks.pop();
84 lk.unlock(); // what() might need to schedule another task
85 task.what();
86 }
87 }
88
89 } // namespace android
90