text: /*
   * Copyright (C) 2015-2016 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.
   */
  
  #include "Worker.h"
  
  #include <sys/prctl.h>
  #include <sys/resource.h>
  
  namespace android {
  
  Worker::Worker(const char *name, int priority)
      : name_(name), priority_(priority), exit_(false), initialized_(false) {
  }
  
  Worker::~Worker() {
    Exit();
  }
  
  int Worker::InitWorker() {
    std::lock_guard<std::mutex> lk(mutex_);
    if (initialized())
      return -EALREADY;
  
    thread_ = std::make_unique<std::thread>(&Worker::InternalRoutine, this);
    initialized_ = true;
    exit_ = false;
  
    return 0;
  }
  
  void Worker::Exit() {
    std::unique_lock<std::mutex> lk(mutex_);
    exit_ = true;
    if (initialized()) {
      lk.unlock();
      cond_.notify_all();
      thread_->join();
      initialized_ = false;
    }
  }
  
  int Worker::WaitForSignalOrExitLocked(int64_t max_nanoseconds) {
    int ret = 0;
    if (should_exit())
      return -EINTR;
  
    std::unique_lock<std::mutex> lk(mutex_, std::adopt_lock);
    if (max_nanoseconds < 0) {
      cond_.wait(lk);
    } else if (std::cv_status::timeout ==
               cond_.wait_for(lk, std::chrono::nanoseconds(max_nanoseconds))) {
      ret = -ETIMEDOUT;
    }
  
    // exit takes precedence on timeout
    if (should_exit())
      ret = -EINTR;
  
    // release leaves mutex locked when going out of scope
    lk.release();
  
    return ret;
  }
  
  void Worker::InternalRoutine() {
    setpriority(PRIO_PROCESS, 0, priority_);
    prctl(PR_SET_NAME, name_.c_str());
  
    std::unique_lock<std::mutex> lk(mutex_, std::defer_lock);
  
    while (true) {
      lk.lock();
      if (should_exit())
        return;
      lk.unlock();
  
      Routine();
    }
  }
  }  // namespace android
  