queue.h

// Copyright The SOLA Contributors
//
// Licensed under the MIT License.
// For details on the licensing terms, see the LICENSE file.
// SPDX-License-Identifier: MIT
 
#ifndef SOLANET_NETWORK_UDP_QUEUE_H_
#define SOLANET_NETWORK_UDP_QUEUE_H_
 
#include <condition_variable>
#include <mutex>
#include <queue>
 
namespace solanet {
template <typename T> class Queue {
public:
  ~Queue() {
    cv_queue_.notify_all();  // Unblock all waiting
  }
 
  void push(const T &value) {
    {
      std::scoped_lock lock(queue_mutex_);
      queue_.push(value);
    }
 
    // Notify a thread waiting on pop() that a new message is available
    cv_queue_.notify_one();
  }
 
  void stop() {
    running_ = false;
    cv_queue_.notify_all();  // Unblock all waiting
  }
 
  T pop() {
    std::unique_lock lk(queue_mutex_);
    if (queue_.empty()) cv_queue_.wait(lk, [this] { return !running_ || !queue_.empty(); });
 
    if (!running_) return {};  // Return empty message if we should stop
 
    // Get first entry, pop it and return
    T item = queue_.front();
    queue_.pop();
    return item;
  }
 
private:
  std::queue<T> queue_;
  std::mutex queue_mutex_;
  bool running_ = true;
  std::condition_variable cv_queue_;
};
}  // namespace solanet
 
#endif  // SOLANET_NETWORK_UDP_QUEUE_H_