fix(session): wait for KWin before starting GUI processes

session/cutefish-wayland-session

@@ -18,4 +18,4 @@ export DESKTOP_SESSION=Cutefish
 # spice-vdagent. The agent uses X11 selections and cannot connect to the
 # native Wayland display directly; KWin bridges the Xwayland clipboard into
 # the Wayland session.
-exec /usr/bin/kwin_wayland --xwayland --exit-with-session /usr/bin/cutefish-kwin-wayland-session "$@"
+exec /usr/bin/kwin_wayland_wrapper --xwayland --exit-with-session /usr/bin/cutefish-kwin-wayland-session "$@"

session/cutefish-wayland.desktop

@@ -2,7 +2,7 @@
 Name=Cutefish (KWin Wayland)
 Comment=Cutefish desktop session on KWin Wayland
 Exec=/usr/bin/cutefish-wayland-session
-TryExec=/usr/bin/kwin_wayland
+TryExec=/usr/bin/kwin_wayland_wrapper
 Type=Application
 DesktopNames=Cutefish;KDE;
 X-GDM-SessionRegisters=true

session/processmanager.cpp

@@ -30,8 +30,11 @@
 #include <QTimer>
 #include <QThread>
 #include <QDir>
+#include <QDBusConnectionInterface>
 #include <QDBusInterface>
 #include <QDBusPendingCall>
+#include <QDBusReply>
+#include <QDBusServiceWatcher>
 
 ProcessManager::ProcessManager(Application *app, QObject *parent)
     : QObject(parent)
@@ -52,6 +55,37 @@ ProcessManager::~ProcessManager()
 
 void ProcessManager::start()
 {
+    if (m_kwinReady)
+        return;
+
+    const QString serviceName = QStringLiteral("org.kde.KWinWrapper");
+    m_kwinWatcher = new QDBusServiceWatcher(serviceName,
+                                             QDBusConnection::sessionBus(),
+                                             QDBusServiceWatcher::WatchForRegistration,
+                                             this);
+    connect(m_kwinWatcher, &QDBusServiceWatcher::serviceRegistered,
+            this, [this](const QString &) {
+        startAfterKWinReady();
+    });
+
+    if (QDBusConnectionInterface *interface = QDBusConnection::sessionBus().interface()) {
+        const QDBusReply<bool> reply = interface->isServiceRegistered(serviceName);
+        if (reply.isValid() && reply.value())
+            startAfterKWinReady();
+    }
+}
+
+void ProcessManager::startAfterKWinReady()
+{
+    if (m_kwinReady)
+        return;
+
+    m_kwinReady = true;
+    if (m_kwinWatcher) {
+        m_kwinWatcher->deleteLater();
+        m_kwinWatcher = nullptr;
+    }
+
     // The settings daemon owns the Cutefish settings D-Bus service and
     // starts the desktop components after that service is ready.
     startDaemonProcess();
@@ -89,6 +123,16 @@ void ProcessManager::stopProcesses(QMap<QString, QProcess *> &processes)
 
 void ProcessManager::startDesktopProcess()
 {
+    if (!m_kwinReady) {
+        qWarning() << "Ignoring desktop startup before KWin is ready";
+        return;
+    }
+
+    if (m_desktopStarted)
+        return;
+
+    m_desktopStarted = true;
+
     // When the cutefish-settings-daemon theme module is loaded, start the desktop.
     // In the way, there will be no problem that desktop and launcher can't get wallpaper.
 

session/processmanager.h

@@ -26,6 +26,7 @@
 #include <QMap>
 
 class Application;
+class QDBusServiceWatcher;
 class ProcessManager : public QObject
 {
     Q_OBJECT
@@ -42,10 +43,14 @@ public:
     void loadAutoStartProcess();
 
 private:
+    void startAfterKWinReady();
     void stopProcesses(QMap<QString, QProcess *> &processes);
 
 private:
     Application *m_app;
+    QDBusServiceWatcher *m_kwinWatcher = nullptr;
+    bool m_kwinReady = false;
+    bool m_desktopStarted = false;
     QMap<QString, QProcess *> m_systemProcess;
     QMap<QString, QProcess *> m_autoStartProcess;