add threadpool for ntcp dh

libi2pd/CryptoWorker.h

@@ -0,0 +1,82 @@
+#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