Ref T301, application contexts pings (by re-registering) identifiers again. By that it can be detected if the GUI is crashed

* ping timer in proxy
* utility function in timestamp list
* adjusted UI component displaying identifiers in core

src/blackcore/context/contextapplication.h

@@ -212,6 +212,8 @@ namespace BlackCore
             virtual QString dotCommandsHtmlHelp() const = 0;
 
         protected:
+            static constexpr int PingIdentifiersMs = 20000; //!< how often identifiers are pinged
+
             //! Constructor
             IContextApplication(CCoreFacadeConfig::ContextMode mode, CCoreFacade *runtime);
 

src/blackcore/context/contextapplicationimpl.cpp

@@ -153,17 +153,22 @@ namespace BlackCore
         CIdentifier CContextApplication::registerApplication(const CIdentifier &application)
         {
             if (m_debugEnabled) { CLogMessage(this, CLogCategory::contextSlot()).debug() << Q_FUNC_INFO << application; }
-            if (!m_registeredApplications.contains(application))
+
+            CIdentifier identifier(application);
+            identifier.setCurrentUtcTime();
+
+            if (!m_registeredApplications.contains(identifier))
             {
-                m_registeredApplications.push_back(application);
+                m_registeredApplications.push_back(identifier);
                 emit this->registrationChanged();
                 emit this->hotkeyActionsRegistered(CInputManager::instance()->allAvailableActions(), {});
             }
             else
             {
-                m_registeredApplications.replace(application, application);
+                m_registeredApplications.replace(application, identifier);
             }
 
+            this->cleanupRegisteredApplications();
             return application;
         }
 
@@ -171,13 +176,21 @@ namespace BlackCore
         {
             if (m_debugEnabled) { CLogMessage(this, CLogCategory::contextSlot()).debug() << Q_FUNC_INFO << application; }
             int r = m_registeredApplications.remove(application);
+            this->cleanupRegisteredApplications();
             if (r > 0) { emit registrationChanged(); }
         }
 
+        void CContextApplication::cleanupRegisteredApplications()
+        {
+            static const int outdatedMs = qRound(1.5 * PingIdentifiersMs);
+            m_registeredApplications.removeOlderThanNowMinusOffset(outdatedMs);
+        }
+
         CIdentifierList CContextApplication::getRegisteredApplications() const
         {
             if (m_debugEnabled) { CLogMessage(this, CLogCategory::contextSlot()).debug() << Q_FUNC_INFO; }
-            return m_registeredApplications;
+            static const int outdatedMs = qRound(1.5 * PingIdentifiersMs);
+            return m_registeredApplications.findAfterNowMinusOffset(outdatedMs);
         }
 
         QString CContextApplication::readFromFile(const QString &fileName) const

src/blackcore/context/contextapplicationimpl.h

@@ -80,6 +80,9 @@ namespace BlackCore
 
         private:
             BlackMisc::CIdentifierList m_registeredApplications;
+
+            //! Housekeeping
+            void cleanupRegisteredApplications();
         };
     } // namespace
 } // namespace

src/blackcore/context/contextapplicationproxy.cpp

@@ -37,6 +37,10 @@ namespace BlackCore
                     CLogHandler::instance()->logRemoteMessage(message);
                 }
             });
+
+            m_pingTimer.setObjectName(serviceName + "::m_pingTimer");
+            connect(&m_pingTimer, &QTimer::timeout, this, &CContextApplicationProxy::reRegisterApplications);
+            m_pingTimer.start(PingIdentifiersMs);
         }
 
         void CContextApplicationProxy::relaySignals(const QString &serviceName, QDBusConnection &connection)
@@ -156,13 +160,15 @@ namespace BlackCore
             m_dBusInterface->callDBus(QLatin1String("callHotkeyAction"), action, argument, origin);
         }
 
-        BlackMisc::CIdentifier CContextApplicationProxy::registerApplication(const CIdentifier &application)
+        CIdentifier CContextApplicationProxy::registerApplication(const CIdentifier &application)
         {
+            m_proxyPingIdentifiers.insert(application);
             return m_dBusInterface->callDBusRet<BlackMisc::CIdentifier>(QLatin1String("registerApplication"), application);
         }
 
         void CContextApplicationProxy::unregisterApplication(const CIdentifier &application)
         {
+            m_proxyPingIdentifiers.remove(application);
             m_dBusInterface->callDBus(QLatin1String("unregisterApplication"), application);
         }
 
@@ -200,6 +206,17 @@ namespace BlackCore
             return m_dBusInterface->callDBusRet<QString>(QLatin1String("dotCommandsHtmlHelp"));
         }
 
+        void CContextApplicationProxy::reRegisterApplications()
+        {
+            if (!m_dBusInterface) { return; }
+            if (m_proxyPingIdentifiers.isEmpty()) { return; }
+            const CIdentifierList identifiers = m_proxyPingIdentifiers; // copy so member can be modified
+            for (const CIdentifier &identifier : identifiers)
+            {
+                this->registerApplication(identifier);
+            }
+        }
+
         bool CContextApplicationProxy::isContextResponsive(const QString &dBusAddress, QString &msg, int timeoutMs)
         {
             const bool connected = CDBusServer::isDBusAvailable(dBusAddress, msg, timeoutMs);

src/blackcore/context/contextapplicationproxy.h

@@ -89,10 +89,15 @@ namespace BlackCore
             CContextApplicationProxy(const QString &serviceName, QDBusConnection &connection, CCoreFacadeConfig::ContextMode mode, CCoreFacade *runtime);
 
         private:
-            BlackMisc::CGenericDBusInterface *m_dBusInterface = nullptr;
+            BlackMisc::CGenericDBusInterface *m_dBusInterface = nullptr; //!< interface
+            BlackMisc::CIdentifierList m_proxyPingIdentifiers; //!< automatically ping the implementing side
+            QTimer m_pingTimer;
 
             //! Relay connection signals to local signals
             void relaySignals(const QString &serviceName, QDBusConnection &connection);
+
+            //! Ping/heartbeat identifiers
+            void reRegisterApplications();
         };
     } // ns
 } // ns