thread_pool.h

// Copyright 2022 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
 
#ifndef PACKAGER_FILE_THREAD_POOL_H_
#define PACKAGER_FILE_THREAD_POOL_H_
 
#include <functional>
#include <queue>
 
#include <absl/base/thread_annotations.h>
#include <absl/synchronization/mutex.h>
 
#include <packager/macros/classes.h>
 
namespace shaka {
 
class ThreadPool {
 public:
  typedef std::function<void()> Task;
 
  ThreadPool();
  ~ThreadPool();
 
  void PostTask(const Task& task);
 
  static ThreadPool instance;
 
 private:
  void Terminate();
 
  Task WaitForTask();
  void ThreadMain();
 
  absl::Mutex mutex_;
  absl::CondVar tasks_available_ ABSL_GUARDED_BY(mutex_);
  std::queue<Task> tasks_ ABSL_GUARDED_BY(mutex_);
  size_t num_idle_threads_ ABSL_GUARDED_BY(mutex_);
  bool terminated_ ABSL_GUARDED_BY(mutex_);
 
  DISALLOW_COPY_AND_ASSIGN(ThreadPool);
};
 
}  // namespace shaka
 
#endif  // PACKAGER_FILE_THREAD_POOL_H_