xref: /aosp_15_r20/hardware/interfaces/camera/common/default/SimpleThread.cpp (revision 4d7e907c777eeecc4c5bd7cf640a754fac206ff7)
1*4d7e907cSAndroid Build Coastguard Worker /*
2*4d7e907cSAndroid Build Coastguard Worker  * Copyright (C) 2022 The Android Open Source Project
3*4d7e907cSAndroid Build Coastguard Worker  *
4*4d7e907cSAndroid Build Coastguard Worker  * Licensed under the Apache License, Version 2.0 (the "License");
5*4d7e907cSAndroid Build Coastguard Worker  * you may not use this file except in compliance with the License.
6*4d7e907cSAndroid Build Coastguard Worker  * You may obtain a copy of the License at
7*4d7e907cSAndroid Build Coastguard Worker  *
8*4d7e907cSAndroid Build Coastguard Worker  *      http://www.apache.org/licenses/LICENSE-2.0
9*4d7e907cSAndroid Build Coastguard Worker  *
10*4d7e907cSAndroid Build Coastguard Worker  * Unless required by applicable law or agreed to in writing, software
11*4d7e907cSAndroid Build Coastguard Worker  * distributed under the License is distributed on an "AS IS" BASIS,
12*4d7e907cSAndroid Build Coastguard Worker  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13*4d7e907cSAndroid Build Coastguard Worker  * See the License for the specific language governing permissions and
14*4d7e907cSAndroid Build Coastguard Worker  * limitations under the License.
15*4d7e907cSAndroid Build Coastguard Worker  */
16*4d7e907cSAndroid Build Coastguard Worker 
17*4d7e907cSAndroid Build Coastguard Worker #include "SimpleThread.h"
18*4d7e907cSAndroid Build Coastguard Worker 
19*4d7e907cSAndroid Build Coastguard Worker namespace android {
20*4d7e907cSAndroid Build Coastguard Worker namespace hardware {
21*4d7e907cSAndroid Build Coastguard Worker namespace camera {
22*4d7e907cSAndroid Build Coastguard Worker namespace common {
23*4d7e907cSAndroid Build Coastguard Worker namespace helper {
24*4d7e907cSAndroid Build Coastguard Worker 
SimpleThread()25*4d7e907cSAndroid Build Coastguard Worker SimpleThread::SimpleThread() : mDone(true), mThread() {}
~SimpleThread()26*4d7e907cSAndroid Build Coastguard Worker SimpleThread::~SimpleThread() {
27*4d7e907cSAndroid Build Coastguard Worker     // Safe to call requestExitAndWait() from the destructor because requestExitAndWait() ensures
28*4d7e907cSAndroid Build Coastguard Worker     // that the thread is joinable before joining on it. This is different from how
29*4d7e907cSAndroid Build Coastguard Worker     // android::Thread worked.
30*4d7e907cSAndroid Build Coastguard Worker     requestExitAndWait();
31*4d7e907cSAndroid Build Coastguard Worker }
32*4d7e907cSAndroid Build Coastguard Worker 
run()33*4d7e907cSAndroid Build Coastguard Worker void SimpleThread::run() {
34*4d7e907cSAndroid Build Coastguard Worker     requestExitAndWait();  // Exit current execution, if any.
35*4d7e907cSAndroid Build Coastguard Worker 
36*4d7e907cSAndroid Build Coastguard Worker     // start thread
37*4d7e907cSAndroid Build Coastguard Worker     mDone.store(false, std::memory_order_release);
38*4d7e907cSAndroid Build Coastguard Worker     mThread = std::thread(&SimpleThread::runLoop, this);
39*4d7e907cSAndroid Build Coastguard Worker }
40*4d7e907cSAndroid Build Coastguard Worker 
requestExitAndWait()41*4d7e907cSAndroid Build Coastguard Worker void SimpleThread::requestExitAndWait() {
42*4d7e907cSAndroid Build Coastguard Worker     // Signal thread to stop
43*4d7e907cSAndroid Build Coastguard Worker     mDone.store(true, std::memory_order_release);
44*4d7e907cSAndroid Build Coastguard Worker 
45*4d7e907cSAndroid Build Coastguard Worker     // Wait for thread to exit if needed. This should happen in no more than one iteration of
46*4d7e907cSAndroid Build Coastguard Worker     // threadLoop
47*4d7e907cSAndroid Build Coastguard Worker     if (mThread.joinable()) {
48*4d7e907cSAndroid Build Coastguard Worker         mThread.join();
49*4d7e907cSAndroid Build Coastguard Worker     }
50*4d7e907cSAndroid Build Coastguard Worker     mThread = std::thread();
51*4d7e907cSAndroid Build Coastguard Worker }
52*4d7e907cSAndroid Build Coastguard Worker 
runLoop()53*4d7e907cSAndroid Build Coastguard Worker void SimpleThread::runLoop() {
54*4d7e907cSAndroid Build Coastguard Worker     while (!exitPending()) {
55*4d7e907cSAndroid Build Coastguard Worker         if (!threadLoop()) {
56*4d7e907cSAndroid Build Coastguard Worker             break;
57*4d7e907cSAndroid Build Coastguard Worker         }
58*4d7e907cSAndroid Build Coastguard Worker     }
59*4d7e907cSAndroid Build Coastguard Worker }
60*4d7e907cSAndroid Build Coastguard Worker 
61*4d7e907cSAndroid Build Coastguard Worker }  // namespace helper
62*4d7e907cSAndroid Build Coastguard Worker }  // namespace common
63*4d7e907cSAndroid Build Coastguard Worker }  // namespace camera
64*4d7e907cSAndroid Build Coastguard Worker }  // namespace hardware
65*4d7e907cSAndroid Build Coastguard Worker }  // namespace android