| /* | 
 |  * Copyright 2021 The Android Open Source Project | 
 |  * | 
 |  * Licensed under the Apache License, Version 2.0 (the "License"); | 
 |  * you may not use this file except in compliance with the License. | 
 |  * You may obtain a copy of the License at | 
 |  * | 
 |  *      http://www.apache.org/licenses/LICENSE-2.0 | 
 |  * | 
 |  * Unless required by applicable law or agreed to in writing, software | 
 |  * distributed under the License is distributed on an "AS IS" BASIS, | 
 |  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | 
 |  * See the License for the specific language governing permissions and | 
 |  * limitations under the License. | 
 |  */ | 
 |  | 
 | #pragma once | 
 |  | 
 | #include <android-base/thread_annotations.h> | 
 | #include <utils/Singleton.h> | 
 | #include <condition_variable> | 
 | #include <mutex> | 
 | #include <queue> | 
 | #include <thread> | 
 |  | 
 | namespace android { | 
 |  | 
 | // Executes tasks off the main thread. | 
 | class BackgroundExecutor : public Singleton<BackgroundExecutor> { | 
 | public: | 
 |     BackgroundExecutor(); | 
 |     ~BackgroundExecutor(); | 
 |     void execute(std::function<void()>); | 
 |  | 
 | private: | 
 |     std::mutex mMutex; | 
 |     std::condition_variable mWorkAvailableCv GUARDED_BY(mMutex); | 
 |     bool mDone GUARDED_BY(mMutex) = false; | 
 |     std::vector<std::function<void()>> mTasks GUARDED_BY(mMutex); | 
 |     std::thread mThread; | 
 | }; | 
 |  | 
 | } // namespace android |