Fix network listener shutdown

Reviewers: mculinovic, buda

Reviewed By: mculinovic

Subscribers: teon.banek, pullbot

Differential Revision: https://phabricator.memgraph.io/D1603

src/communication/listener.hpp

@@ -85,11 +85,8 @@ class Listener final {
   }
 
   ~Listener() {
-    alive_.store(false);
-    if (timeout_thread_.joinable()) timeout_thread_.join();
-    for (auto &worker_thread : worker_threads_) {
-      worker_thread.join();
-    }
+    Shutdown();
+    AwaitShutdown();
   }
 
   Listener(const Listener &) = delete;
@@ -122,6 +119,22 @@ class Listener final {
                sessions_.back().get());
   }
 
+  /**
+   * This function starts a graceful shutdown of the listener.
+   */
+  void Shutdown() { alive_.store(false); }
+
+  /**
+   * This function blocks the calling thread until the listener shutdown is
+   * complete.
+   */
+  void AwaitShutdown() {
+    if (timeout_thread_.joinable()) timeout_thread_.join();
+    for (auto &worker_thread : worker_threads_) {
+      if (worker_thread.joinable()) worker_thread.join();
+    }
+  }
+
  private:
   /**
    * This function polls the event queue and processes incoming data.

src/communication/server.hpp

@@ -98,11 +98,14 @@ class Server final {
     alive_.store(false);
     // Shutdown the socket to return from any waiting `Accept` calls.
     socket_.Shutdown();
+    // Shutdown the listener.
+    listener_.Shutdown();
   }
 
   /// Waits for the server to be signaled to shutdown
   void AwaitShutdown() {
     if (thread_.joinable()) thread_.join();
+    listener_.AwaitShutdown();
   }
 
  private: