Cleanup aircraft in X-Plane after DBusConnection drops

ref T392

src/xswiftbus/dbusconnection.cpp

@@ -26,10 +26,11 @@ namespace XSwiftBus
 
     CDBusConnection::CDBusConnection(DBusConnection *connection)
     {
+        m_connection.reset(connection);
         dbus_connection_ref(connection);
         // Don't exit application, if the connection is disconnected
         dbus_connection_set_exit_on_disconnect(connection, false);
-        m_connection.reset(connection);
+        dbus_connection_add_filter(connection, filterDisconnectedFunction, this, nullptr);
     }
 
     CDBusConnection::~CDBusConnection()
@@ -98,6 +99,11 @@ namespace XSwiftBus
         return m_connection && dbus_connection_get_is_connected(m_connection.get());
     }
 
+    void CDBusConnection::registerDisconnectedCallback(DisconnectedCallback func)
+    {
+        m_disconnectedCallbacks.push_back(func);
+    }
+
     void CDBusConnection::registerObjectPath(CDBusObject *object, const std::string &interfaceName, const std::string &objectPath, const DBusObjectPathVTable &dbusObjectPathVTable)
     {
         (void) interfaceName;
@@ -149,4 +155,24 @@ namespace XSwiftBus
         return obj->setDispatchStatus(connection, status);
     }
 
+    DBusHandlerResult CDBusConnection::filterDisconnectedFunction(DBusConnection *connection, DBusMessage *message, void *data)
+    {
+        (void)connection; // unused
+
+        auto *obj = static_cast<CDBusConnection *>(data);
+
+        DBusError err;
+        dbus_error_init(&err);
+
+        if (dbus_message_is_signal (message, DBUS_INTERFACE_LOCAL, "Disconnected"))
+        {
+            for (const auto &cb : obj->m_disconnectedCallbacks)
+            {
+                cb();
+            }
+            return DBUS_HANDLER_RESULT_HANDLED;
+        }
+        return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+    }
+
 }

src/xswiftbus/dbusconnection.h

@@ -34,6 +34,9 @@ namespace XSwiftBus
         //! Bus type
         enum BusType { SessionBus };
 
+        //! Disconnect Callback
+        using DisconnectedCallback = std::function<void()>;
+
         //! Default constructor
         CDBusConnection();
 
@@ -41,7 +44,7 @@ namespace XSwiftBus
         CDBusConnection(DBusConnection *connection);
 
         //! Destructor
-        ~CDBusConnection();
+        ~CDBusConnection() override;
 
         // The ones below are not implemented yet.
         // If you need them, make sure that connection reference count is correct
@@ -60,6 +63,9 @@ namespace XSwiftBus
         //! Is connected?
         bool isConnected() const;
 
+        //! Register a disconnected callback
+        void registerDisconnectedCallback(DisconnectedCallback func);
+
         //! Register DBus object with interfaceName and objectPath.
         //! \param object
         //! \param interfaceName
@@ -82,6 +88,7 @@ namespace XSwiftBus
     private:
         void setDispatchStatus(DBusConnection *connection, DBusDispatchStatus status);
         static void setDispatchStatus(DBusConnection *connection, DBusDispatchStatus status, void *data);
+        static DBusHandlerResult filterDisconnectedFunction(DBusConnection *connection, DBusMessage *message, void *data);
 
         struct DBusConnectionDeleter
         {
@@ -91,6 +98,7 @@ namespace XSwiftBus
         CDBusDispatcher *m_dispatcher = nullptr;
         std::unique_ptr<DBusConnection, DBusConnectionDeleter> m_connection;
         CDBusError m_lastError;
+        std::vector<DisconnectedCallback> m_disconnectedCallbacks;
     };
 
 }

src/xswiftbus/dbusobject.cpp

@@ -20,6 +20,9 @@ namespace XSwiftBus
     void CDBusObject::setDBusConnection(const std::shared_ptr<CDBusConnection> &dbusConnection)
     {
         m_dbusConnection = dbusConnection;
+        dbusConnectedHandler();
+        CDBusConnection::DisconnectedCallback disconnectedHandler = std::bind(&CDBusObject::dbusDisconnectedHandler, this);
+        m_dbusConnection->registerDisconnectedCallback(disconnectedHandler);
     }
 
     void CDBusObject::registerDBusObjectPath(const std::string &interfaceName, const std::string &objectPath)

src/xswiftbus/dbusobject.h

@@ -36,9 +36,15 @@ namespace XSwiftBus
         void registerDBusObjectPath(const std::string &interfaceName, const std::string &objectPath);
 
     protected:
+        //! Handler which is called when DBusCconnection is established
+        virtual void dbusConnectedHandler() {}
+
         //! DBus message handler
         virtual DBusHandlerResult dbusMessageHandler(const CDBusMessage &message) = 0;
 
+        //! Handler which is called when DBusConnection disconnected
+        virtual void dbusDisconnectedHandler() {}
+
         //! Send DBus signal
         void sendDBusSignal(const std::string &name);
 

src/xswiftbus/traffic.cpp

@@ -445,6 +445,11 @@ namespace XSwiftBus
         enableFollowPlaneView(callsign);
     }
 
+    void CTraffic::dbusDisconnectedHandler()
+    {
+        removeAllPlanes();
+    }
+
     const char *introspection_traffic =
         DBUS_INTROSPECT_1_0_XML_DOCTYPE_DECL_NODE
 #include "org.swift_project.xswiftbus.traffic.xml"

src/xswiftbus/traffic.h

@@ -122,6 +122,8 @@ namespace XSwiftBus
         int process();
 
     protected:
+        virtual void dbusDisconnectedHandler() override;
+
         DBusHandlerResult dbusMessageHandler(const CDBusMessage &message) override;
 
     private: