Sunshine/sunshine/thread_safe.h

//
// Created by loki on 6/10/19.
//

#ifndef SUNSHINE_THREAD_SAFE_H
#define SUNSHINE_THREAD_SAFE_H

#include <vector>
#include <mutex>
#include <condition_variable>

#include "utility.h"

namespace safe {
template<class T>
class event_t {
  using status_t = util::optional_t<T>;

public:
  template<class...Args>
  void raise(Args &&...args) {
    std::lock_guard lg { _lock };
    if(!_continue) {
      return;
    }

    _status = status_t { std::forward<Args>(args)... };

    _cv.notify_all();
  }

  // pop and view shoud not be used interchangebly
  status_t pop() {
    std::unique_lock ul{_lock};

    if (!_continue) {
      return util::false_v<status_t>;
    }

    while (!_status) {
      _cv.wait(ul);

      if (!_continue) {
        return util::false_v<status_t>;
      }
    }

    auto val = std::move(_status);
    _status = util::false_v<status_t>;
    return val;
  }

  // pop and view shoud not be used interchangebly
  const status_t &view() {
    std::unique_lock ul{_lock};

    if (!_continue) {
      return util::false_v<status_t>;
    }

    while (!_status) {
      _cv.wait(ul);

      if (!_continue) {
        return util::false_v<status_t>;
      }
    }

    return _status;
  }

  bool peek() {
    std::lock_guard lg { _lock };

    return (bool)_status;
  }

  void stop() {
    std::lock_guard lg{_lock};

    _continue = false;

    _cv.notify_all();
  }

  bool running() const {
    return _continue;
  }
private:

  bool _continue{true};
  status_t _status;

  std::condition_variable _cv;
  std::mutex _lock;
};

template<class T>
class queue_t {
  using status_t = util::optional_t<T>;

public:
  template<class ...Args>
  void raise(Args &&... args) {
    std::lock_guard lg{_lock};

    if(!_continue) {
      return;
    }

    _queue.emplace_back(std::forward<Args>(args)...);

    _cv.notify_all();
  }

  bool peek() {
    std::lock_guard lg { _lock };

    return !_queue.empty();
  }

  status_t pop() {
    std::unique_lock ul{_lock};

    if (!_continue) {
      return util::false_v<status_t>;
    }

    while (_queue.empty()) {
      _cv.wait(ul);

      if (!_continue) {
        return util::false_v<status_t>;
      }
    }

    auto val = std::move(_queue.front());
    _queue.erase(std::begin(_queue));

    return val;
  }

  std::vector<T> &unsafe() {
    return _queue;
  }

  void stop() {
    std::lock_guard lg{_lock};

    _continue = false;

    _cv.notify_all();
  }

  [[nodiscard]] bool running() const {
    return _continue;
  }

private:

  bool _continue{true};

  std::mutex _lock;
  std::condition_variable _cv;
  std::vector<T> _queue;
};

}

#endif //SUNSHINE_THREAD_SAFE_H