(socket server) add a callback to the ConnectionState to be invoked when the connection is terminated. This will be used by the SocketServer in the future to know on time that the associated connection thread can be terminated.

ixwebsocket/IXConnectionState.h

@@ -7,12 +7,15 @@
 #pragma once
 
 #include <atomic>
+#include <functional>
 #include <memory>
 #include <stdint.h>
 #include <string>
 
 namespace ix
 {
+    using OnSetTerminatedCallback = std::function<void()>;
+
     class ConnectionState
     {
     public:
@@ -27,10 +30,16 @@ namespace ix
 
         static std::shared_ptr<ConnectionState> createConnectionState();
 
+    private:
+        void setOnSetTerminatedCallback(const OnSetTerminatedCallback& callback);
+
     protected:
         std::atomic<bool> _terminated;
         std::string _id;
+        OnSetTerminatedCallback _onSetTerminatedCallback;
 
         static std::atomic<uint64_t> _globalId;
+
+        friend class SocketServer;
     };
 } // namespace ix