Implement single instance check using DBus

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - SPDX license identifiers (GPL-3.0-or-later) to all source files.
+- Single instance application check via DBus to prevent multiple concurrent instances.
 
 ### Changed
 

src/main.cpp

@@ -3,6 +3,8 @@
 
 #include <QApplication>
 #include <QDBusConnection>
+#include <QDBusConnectionInterface>
+#include <QDBusMessage>
 #include <QIcon>
 #include <QLocale>
 #include <QQmlApplicationEngine>
@@ -23,6 +25,18 @@ int main(int argc, char *argv[])
     QApplication::setApplicationVersion(QStringLiteral("1.0.1"));
 
     QApplication app(argc, argv);
+
+    QDBusConnection sessionBus = QDBusConnection::sessionBus();
+    if (sessionBus.isConnected() && sessionBus.interface() && sessionBus.interface()->isServiceRegistered(QStringLiteral("org.mpris.MediaPlayer2.bearwave"))) {
+        QDBusMessage call = QDBusMessage::createMethodCall(
+            QStringLiteral("org.mpris.MediaPlayer2.bearwave"),
+            QStringLiteral("/org/mpris/MediaPlayer2"),
+            QStringLiteral("org.mpris.MediaPlayer2"),
+            QStringLiteral("Raise")
+        );
+        sessionBus.call(call);
+        return 0;
+    }
     app.setWindowIcon(QIcon::fromTheme(QStringLiteral("de.nerdbear.bearwave")));
     app.setQuitOnLastWindowClosed(false);
 
@@ -45,7 +59,6 @@ int main(int argc, char *argv[])
     Q_UNUSED(controlAdaptor)
     Q_UNUSED(notificationManager)
 
-    QDBusConnection sessionBus = QDBusConnection::sessionBus();
     sessionBus.registerObject(QStringLiteral("/org/mpris/MediaPlayer2"), &backend, QDBusConnection::ExportAdaptors);
     sessionBus.registerService(QStringLiteral("org.mpris.MediaPlayer2.bearwave"));
 

src/mprisadaptor.cpp

@@ -58,7 +58,7 @@ bool MprisRootAdaptor::canSetFullscreen() const
 
 bool MprisRootAdaptor::canRaise() const
 {
-    return false;
+    return true;
 }
 
 bool MprisRootAdaptor::hasTrackList() const
@@ -94,6 +94,7 @@ QStringList MprisRootAdaptor::supportedMimeTypes() const
 
 void MprisRootAdaptor::Raise()
 {
+    emit m_backend->raiseRequested();
 }
 
 void MprisRootAdaptor::Quit()

src/qml/Main.qml

@@ -20,6 +20,15 @@ ApplicationWindow {
         root.hide()
     }
 
+    Connections {
+        target: backend
+        function onRaiseRequested() {
+            root.show()
+            root.raise()
+            root.requestActivate()
+        }
+    }
+
     Platform.SystemTrayIcon {
         id: systray
         visible: true

src/radiobackend.h

@@ -83,6 +83,7 @@ signals:
     void resumeStateChanged();
     void filterQueryChanged();
     void currentStationChanged();
+    void raiseRequested();
 
 private slots:
     void onStationsLoaded(const QList<RadioStation*> &stations);