volumeosd: Listen to osd service for opening the popup

Fixes: https://invent.kde.org/plasma/plasma-mobile/-/issues/423

We currently listen to when the volume changes, which wouldn't happen if
the user reaches 0% or 100% and continues trying to press the volume
button. Instead, listen to OSD events for determining when to open the
popup.

components/mobileshell/qml/dataproviders/AudioInfo.qml

@@ -6,6 +6,7 @@ pragma Singleton
 import QtQuick
 
 import org.kde.plasma.private.volume
+import org.kde.plasma.private.mobileshell as MobileShell
 
 QtObject {
     id: root
@@ -100,21 +101,16 @@ QtObject {
         return icon;
     }
 
-    // emitted when the volume changed, but not due to sink switching
-    signal volumeChanged()
-
     property var updateVolume: Connections {
         target: root.paSinkModel ? (PreferredDevice.sink ? PreferredDevice.sink : null) : null
         enabled: target !== null
 
         function onVolumeChanged() {
             root.volumeValue = root.volumePercent(PreferredDevice.sink.volume, root.maxVolumeValue);
-            root.volumeChanged();
         }
 
         function onMutedChanged() {
             root.volumeValue = PreferredDevice.sink.muted ? 0 : root.volumePercent(PreferredDevice.sink.volume, root.maxVolumeValue);
-            root.volumeChanged();
         }
     }
 

components/mobileshell/qml/popups/volumeosd/VolumeOSDProvider.qml

@@ -19,14 +19,14 @@ import org.kde.plasma.private.mobileshell as MobileShell
 QtObject {
     id: component
 
-    function showVolumeOverlay() {
-        if (!osd.visible) {
-            vcp.showOverlay();
-        }
-    }
+    property var osdListener: Connections {
+        target: MobileShellState.VolumeOSDListener
 
-    Component.onCompleted: {
-        MobileShell.AudioInfo.volumeChanged.connect(showVolumeOverlay);
+        function onShowOSD(icon, volume, maxVolume) {
+            if (!osd.visible) {
+                vcp.showOverlay();
+            }
+        }
     }
 
     property var apiListener: Connections {

components/mobileshellstate/CMakeLists.txt

@@ -7,6 +7,7 @@ set(mobileshellstateplugin_SRCS
     lockscreendbusclient.cpp
     startupfeedbackmodel.cpp
     windowlistener.cpp
+    volumeosdlistener.cpp
 )
 
 qt_generate_dbus_interface(

components/mobileshellstate/volumeosdlistener.cpp

@@ -0,0 +1,45 @@
+// SPDX-FileCopyrightText: 2025 Devin Lin <devin@kde.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "volumeosdlistener.h"
+
+#include <QDBusConnection>
+#include <QDBusInterface>
+#include <QDBusReply>
+#include <QDBusServiceWatcher>
+#include <QDebug>
+#include <QString>
+
+using namespace Qt::StringLiterals;
+
+VolumeOSDListener::VolumeOSDListener(QObject *parent)
+    : QObject{parent}
+{
+    QDBusServiceWatcher *watcher =
+        new QDBusServiceWatcher(QStringLiteral("org.kde.plasmashell"), QDBusConnection::sessionBus(), QDBusServiceWatcher::WatchForOwnerChange, this);
+
+    connect(watcher, &QDBusServiceWatcher::serviceRegistered, this, [this]() -> void {
+        connectDBus();
+    });
+
+    connectDBus();
+}
+
+void VolumeOSDListener::connectDBus()
+{
+    bool success = QDBusConnection::sessionBus().connect(QStringLiteral("org.kde.plasmashell"),
+                                                         QStringLiteral("/org/kde/osdService"),
+                                                         QStringLiteral("org.kde.osdService"),
+                                                         QStringLiteral("osdProgress"),
+                                                         this,
+                                                         SLOT(onOSDProgress(QString, int, int, QString)));
+}
+
+void VolumeOSDListener::onOSDProgress(const QString &icon, int volume, int maxVolume, const QString &text)
+{
+    Q_UNUSED(text)
+
+    if (icon == "audio-volume-muted"_L1 || icon == "audio-volume-low"_L1 || icon == "audio-volume-medium"_L1 || icon == "audio-volume-high"_L1) {
+        Q_EMIT showOSD(icon, volume, maxVolume);
+    }
+}

components/mobileshellstate/volumeosdlistener.h

@@ -0,0 +1,26 @@
+// SPDX-FileCopyrightText: 2025 Devin Lin <devin@kde.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <QObject>
+#include <qqmlregistration.h>
+
+class VolumeOSDListener : public QObject
+{
+    Q_OBJECT
+    QML_ELEMENT
+    QML_SINGLETON
+
+public:
+    VolumeOSDListener(QObject *parent = nullptr);
+
+Q_SIGNALS:
+    void showOSD(const QString &icon, int volume, int maxVolume);
+
+private Q_SLOTS:
+    void onOSDProgress(const QString &icon, int volume, int maxVolume, const QString &text);
+
+private:
+    void connectDBus();
+};