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      1 /*
      2  * Copyright (C) 2013 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 <pthread.h>
     18 #include <sched.h>
     19 #include <sys/resource.h>
     20 
     21 #include <cutils/sched_policy.h>
     22 #include <log/log.h>
     23 #include <system/thread_defs.h>
     24 
     25 #include "EventControlThread.h"
     26 
     27 namespace android {
     28 
     29 EventControlThread::~EventControlThread() = default;
     30 
     31 namespace impl {
     32 
     33 EventControlThread::EventControlThread(EventControlThread::SetVSyncEnabledFunction function)
     34       : mSetVSyncEnabled(function) {
     35     pthread_setname_np(mThread.native_handle(), "EventControlThread");
     36 
     37     pid_t tid = pthread_gettid_np(mThread.native_handle());
     38     setpriority(PRIO_PROCESS, tid, ANDROID_PRIORITY_URGENT_DISPLAY);
     39     set_sched_policy(tid, SP_FOREGROUND);
     40 }
     41 
     42 EventControlThread::~EventControlThread() {
     43     {
     44         std::lock_guard<std::mutex> lock(mMutex);
     45         mKeepRunning = false;
     46         mCondition.notify_all();
     47     }
     48     mThread.join();
     49 }
     50 
     51 void EventControlThread::setVsyncEnabled(bool enabled) {
     52     std::lock_guard<std::mutex> lock(mMutex);
     53     mVsyncEnabled = enabled;
     54     mCondition.notify_all();
     55 }
     56 
     57 // Unfortunately std::unique_lock gives warnings with -Wthread-safety
     58 void EventControlThread::threadMain() NO_THREAD_SAFETY_ANALYSIS {
     59     auto keepRunning = true;
     60     auto currentVsyncEnabled = false;
     61 
     62     while (keepRunning) {
     63         mSetVSyncEnabled(currentVsyncEnabled);
     64 
     65         std::unique_lock<std::mutex> lock(mMutex);
     66         mCondition.wait(lock, [this, currentVsyncEnabled, keepRunning]() NO_THREAD_SAFETY_ANALYSIS {
     67             return currentVsyncEnabled != mVsyncEnabled || keepRunning != mKeepRunning;
     68         });
     69         currentVsyncEnabled = mVsyncEnabled;
     70         keepRunning = mKeepRunning;
     71     }
     72 }
     73 
     74 } // namespace impl
     75 } // namespace android
     76