i2pd/libi2pd/CryptoWorker.h

#ifndef CRYPTO_WORKER_H_
#define CRYPTO_WORKER_H_

#include <condition_variable>
#include <mutex>
#include <deque>
#include <thread>
#include <vector>
#include <pair>
#include <memory>

namespace i2p
{
namespace worker
{
  template<typename Caller>
  struct ThreadPool
  {
    typedef std::function<void(void)> ResultFunc;
    typedef std::function<Result(void)> WorkFunc;
    typedef std::pair<std::shared_ptr<Caller>, WorkFunc> Job;
    typedef std::mutex mtx_t;
    typedef std::unique_lock<mtx_t> lock_t;
    typedef std::condition_variable cond_t;
    ThreadPool(int workers)
    {
      stop = false;
      if(workers > 0)
      {
        while(workers--)
        {
          threads.emplace_back([this] {
              Job job;
              for (;;)
              {
                {
                  lock_t lock(this->queue_mutex);
                  this->condition.wait(
                    lock, [this] { return this->stop || !this->jobs.empty(); });
                  if (this->stop && this->jobs.empty()) return;
                  job = std::move(this->jobs.front());
                  this->jobs.pop_front();
                }
              }
              job.first->GetService().post(job.second());
          });
        }
      }
    };

    void Offer(const Job & job)
    {
      {
        lock_t lock(queue_mutex);
        if (stop) return;
        jobs.emplace_back(job);
      }
      condition.notify_one();
    }

    ~ThreadPool()
    {
      {
        lock_t lock(queue_mutex);
        stop = true;
      }
      condition.notify_all();
      for(auto &t: threads) t.join();
    }

    std::vector<std::thread> threads;
    std::deque<Job> jobs;
    mtx_t queue_mutex;
    cond_t condition;
    bool stop;
    
  };
}
}


#endif