thread.hpp

// FEAT3: Finite Element Analysis Toolbox, Version 3
// Copyright (C) 2010 by Stefan Turek & the FEAT group
// FEAT3 is released under the GNU General Public License version 3,
// see the file 'copyright.txt' in the top level directory for details.
 
#pragma once
 
#include <kernel/base_header.hpp>
 
#include <condition_variable>
#include <mutex>
#include <thread>
 
namespace FEAT
{
  class ThreadFence
  {
  private:
    std::mutex _mtx;
    std::condition_variable _cvar;
    bool _open;
    bool _okay;
 
  public:
    explicit ThreadFence() : _open(false), _okay(false) {}
 
    ThreadFence(const ThreadFence&) = delete;
    ThreadFence& operator=(const ThreadFence&) = delete;
 
    bool wait()
    {
      std::unique_lock<std::mutex> lock(_mtx);
      // we must to use a while loop here to correctly handle spurious wake-ups
      while(!_open)
        _cvar.wait(lock);
      return _okay;
    }
 
    void open(bool okay = true)
    {
      std::unique_lock<std::mutex> lock(_mtx);
      _open = true;
      _okay = okay;
      _cvar.notify_all();
    }
 
    void close()
    {
      std::unique_lock<std::mutex> lock(_mtx);
      _open = _okay = false;
    }
  }; // class ThreadFence
} // namespace FEAT