Add MqttClassBinder

src/MqttClassBinder.h

@@ -0,0 +1,72 @@
+// MqttReceiver must implement onPublish(...)
+template <class MqttReceiver>
+class MqttClassBinder
+{
+  public:
+    MqttClassBinder()
+    {
+      unregister(this);
+    }
+    ~MqttClassBinder() { unregister(this); }
+    
+    static void onUnpublished(MqttClient::CallBack handler)
+    {
+      unrouted_handler = handler;
+    }
+
+    static void onPublish(MqttClient* client, MqttReceiver* dest)
+    {
+      routes.insert(std::pair<MqttClient*, MqttReceiver*>(client, dest));
+      client->setCallback(onRoutePublish);
+    }
+
+    void onPublish(const MqttClient* client, const Topic& topic, const char* payload, size_t length)
+    {
+      static_cast<MqttReceiver*>(this)->MqttReceiver::onPublish(client, topic, payload, length);
+    }
+
+    static size_t size() { return routes.size(); }
+
+    static void reset() { routes.clear(); }
+
+  private:
+
+    static void onRoutePublish(const MqttClient* client, const Topic& topic, const char* payload, size_t length)
+    {
+      bool unrouted = true;
+      auto receivers = routes.equal_range(client);
+      for(auto it = receivers.first; it != receivers.second; ++it)
+      {
+        it->second->onPublish(client, topic, payload, length);
+        unrouted = false;
+      }
+
+      if (unrouted and unrouted_handler)
+      {
+        unrouted_handler(client, topic, payload, length);
+      }
+    }
+
+  private:
+    void unregister(MqttClassBinder<MqttReceiver>* which)
+    {
+      if (routes.size()==0) return;   // bug in map stl
+      for(auto it=routes.begin(); it!=routes.end(); it++)
+        if (it->second == which)
+        {
+          routes.erase(it);
+          return;
+        }
+    }
+
+  static std::multimap<const MqttClient*, MqttClassBinder<MqttReceiver>*> routes;
+  static MqttClient::CallBack unrouted_handler;
+
+};
+
+template<class MqttReceiver>
+std::multimap<const MqttClient*, MqttClassBinder<MqttReceiver>*> MqttClassBinder<MqttReceiver>::routes;
+
+template<class MqttReceiver>
+MqttClient::CallBack MqttClassBinder<MqttReceiver>::unrouted_handler = nullptr;
+