dbustray: Implement better detection of indicator-application

We need to do the icon cache trick all desktops using indicator-application,
these are not limited to Unity. For example, the default Xubuntu and Lubuntu
desktops use indicator-application too.

Without this, tray icons will be improperly shown on these desktops.

Change-Id: Id397bbe9b594152d7c3a29c36c853e928af7dde4
Reviewed-by: Shawn Rutledge <shawn.rutledge@theqtcompany.com>

2 files changed, 18 insertions, 3 deletions

diff --git a/src/corelib/io/qlockfile_p.h b/src/corelib/io/qlockfile_p.h
index 48b642abd0..468b4c0d29 100644
--- a/src/corelib/io/qlockfile_p.h
+++ b/src/corelib/io/qlockfile_p.h
@@ -75,7 +75,8 @@ public:
     // Returns \c true if the lock belongs to dead PID, or is old.
     // The attempt to delete it will tell us if it was really stale or not, though.
     bool isApparentlyStale() const;
-    static QString processNameByPid(qint64 pid);
+    // used in dbusmenu
+    Q_CORE_EXPORT static QString processNameByPid(qint64 pid);
 
 #ifdef Q_OS_UNIX
     static int checkFcntlWorksAfterFlock(const QString &fn);
diff --git a/src/platformsupport/dbustray/qdbustrayicon.cpp b/src/platformsupport/dbustray/qdbustrayicon.cpp
index 87083c8a55..7dbdb3a35b 100644
--- a/src/platformsupport/dbustray/qdbustrayicon.cpp
+++ b/src/platformsupport/dbustray/qdbustrayicon.cpp
@@ -47,13 +47,19 @@
 #include <qloggingcategory.h>
 #include <qplatformintegration.h>
 #include <qplatformservices.h>
+#include <qdbusconnectioninterface.h>
+#include <private/qlockfile_p.h>
 #include <private/qguiapplication_p.h>
 
+// Defined in Windows headers which get included by qlockfile_p.h
+#undef interface
+
 QT_BEGIN_NAMESPACE
 
 Q_LOGGING_CATEGORY(qLcTray, "qt.qpa.tray")
 
 static const QString KDEItemFormat = QStringLiteral("org.kde.StatusNotifierItem-%1-%2");
+static const QString KDEWatcherService = QStringLiteral("org.kde.StatusNotifierWatcher");
 static const QString TempFileTemplate =  QDir::tempPath() + QStringLiteral("/qt-trayicon-XXXXXX.png");
 static const QString XdgNotificationService = QStringLiteral("org.freedesktop.Notifications");
 static const QString XdgNotificationPath = QStringLiteral("/org/freedesktop/Notifications");
@@ -136,9 +142,17 @@ void QDBusTrayIcon::setStatus(const QString &status)
 
 QTemporaryFile *QDBusTrayIcon::tempIcon(const QIcon &icon)
 {
-    // Hack for Unity, which doesn't handle icons sent across D-Bus:
+    // Hack for indicator-application, which doesn't handle icons sent across D-Bus:
     // save the icon to a temp file and set the icon name to that filename.
-    static bool necessary = (QGuiApplicationPrivate::platformIntegration()->services()->desktopEnvironment().split(':').contains("UNITY"));
+    static bool necessity_checked = false;
+    static bool necessary = false;
+    if (!necessity_checked) {
+        QDBusConnection session = QDBusConnection::sessionBus();
+        uint pid = session.interface()->servicePid(KDEWatcherService).value();
+        QString processName = QLockFilePrivate::processNameByPid(pid);
+        necessary = processName.endsWith(QStringLiteral("indicator-application-service"));
+        necessity_checked = true;
+    }
     if (!necessary)
         return Q_NULLPTR;
     QTemporaryFile *ret = new QTemporaryFile(TempFileTemplate, this);