Ref T709 Prevent instantiation of CXSwiftBusSettingsQtFree, to avoid slicing.

- Constructors and destructor are protected.
- Therefore destructor doesn't need to be virtual.
- objectUpdated is pure virtual, so the class is abstract.
- Both derived classes are declared final.

src/blackmisc/simulation/settings/xswiftbussettings.h

@@ -27,7 +27,7 @@ namespace BlackMisc
         namespace Settings
         {
             //! XSwiftBus settings
-            class BLACKMISC_EXPORT CXSwiftBusSettings :
+            class BLACKMISC_EXPORT CXSwiftBusSettings final :
                 public CValueObject<CXSwiftBusSettings>,
                 public CXSwiftBusSettingsQtFree,
                 public ITimestampBased
@@ -88,7 +88,7 @@ namespace BlackMisc
 
             protected:
                 //! \copydoc CXSwiftBusSettingsQtFree::objectUpdated
-                virtual void objectUpdated() override;
+                virtual void objectUpdated() override final;
 
             private:
                 BLACK_METACLASS(

src/blackmisc/simulation/settings/xswiftbussettingsqtfree.cpp

@@ -147,11 +147,6 @@ namespace BlackMisc
                 const milliseconds ms = duration_cast<milliseconds>(system_clock::now().time_since_epoch());
                 m_msSinceEpochQtFree = static_cast<int64_t>(ms.count());
             }
-
-            void CXSwiftBusSettingsQtFree::objectUpdated()
-            {
-                // void
-            }
         } // ns
     } // ns
 } // ns

src/blackmisc/simulation/settings/xswiftbussettingsqtfree.h

@@ -24,16 +24,17 @@ namespace BlackMisc
              */
             class CXSwiftBusSettingsQtFree
             {
-            public:
+            protected:
                 //! Constructor.
                 CXSwiftBusSettingsQtFree();
 
                 //! JSON Constructor.
                 CXSwiftBusSettingsQtFree(const std::string &json);
 
-                //! Dtor
-                virtual ~CXSwiftBusSettingsQtFree() {}
+                //! Destructor.
+                ~CXSwiftBusSettingsQtFree() = default;
 
+            public:
                 //! DBus server
                 const std::string &getDBusServerAddress() const { return m_dBusServerAddress; }
 
@@ -112,7 +113,7 @@ namespace BlackMisc
                 //! @}
 
                 //! Object has been updated
-                virtual void objectUpdated();
+                virtual void objectUpdated() = 0;
 
                 std::string m_dBusServerAddress { "tcp:host=127.0.0.1,port=45001" }; //!< DBus server
                 std::string m_nightTextureMode  { "auto" }; //!< night texture mode

src/xswiftbus/settings.h

@@ -18,7 +18,7 @@ namespace XSwiftBus
     /*!
      * XSwiftBus/swift side settings class, JSON capable, shared among all services
      */
-    class CSettings : public BlackMisc::Simulation::Settings::CXSwiftBusSettingsQtFree
+    class CSettings final : public BlackMisc::Simulation::Settings::CXSwiftBusSettingsQtFree
     {
     public:
         //! Constructor.
@@ -27,8 +27,9 @@ namespace XSwiftBus
         //! JSON constructor
         CSettings(const std::string &json);
 
-        //! Destructor;
-        virtual ~CSettings() {}
+    protected:
+        //! \copydoc CXSwiftBusSettingsQtFree::objectUpdated
+        virtual void objectUpdated() override final {}
     };
 
     //! Something owning the settings