fix(core): restore session-owned desktop startup

README.md

@@ -14,8 +14,8 @@ declared in `cutefish-services/CMakeLists.txt`.
 For the Wayland session, install KWin Wayland and select `Cutefish (KWin
 Wayland)` from the display manager. The session entry launches KWin with
 Wayland enabled and starts `cutefish-session` inside the
-compositor. The session starts the retained services daemon, which in turn
-starts the desktop components after its D-Bus service is ready.
+compositor. The session starts the retained services daemon, waits for its
+D-Bus service to register, and then starts the desktop components.
 
 ## Build
 

cutefish-services/application.cpp

@@ -19,15 +19,10 @@
 
 #include "application.h"
 #include "poweradaptor.h"
-#include <QStandardPaths>
-#include <QProcess>
-#include <QTimer>
 #include <QFile>
-#include <QDebug>
 #include <QDir>
 #include <QTranslator>
 #include <QLocale>
-#include <QTimer>
 
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -49,8 +44,7 @@ Application::Application(int &argc, char **argv)
 {
     initTrash();
 
-    // connect to D-Bus and register as an object:
-    QDBusConnection::sessionBus().registerService(QStringLiteral("com.cutefish.Services"));
+    // Register all service objects before publishing the well-known name.
     new PowerAdaptor(m_powerManager);
     QDBusConnection::sessionBus().registerObject(QStringLiteral("/com/cutefish/Services/Power"), m_powerManager);
 
@@ -66,18 +60,7 @@ Application::Application(int &argc, char **argv)
         }
     }
 
-    QTimer::singleShot(10, this, &Application::invokeDesktopProcess);
-}
-
-void Application::invokeDesktopProcess()
-{
-    // Start desktop UI component.
-    QDBusInterface sessionInterface("com.cutefish.Session", "/Session", "com.cutefish.Session",
-                                    QDBusConnection::sessionBus());
-
-    if (sessionInterface.isValid()) {
-        sessionInterface.call("startDesktopProcess");
-    }
+    QDBusConnection::sessionBus().registerService(QStringLiteral("com.cutefish.Services"));
 }
 
 void Application::initTrash()

cutefish-services/application.h

@@ -30,8 +30,6 @@
 #include "power/powermanager.h"
 #include "power/cpumanagement.h"
 
-#include <QTimer>
-
 class Application : public QApplication
 {
     Q_OBJECT
@@ -39,7 +37,6 @@ class Application : public QApplication
 public:
     explicit Application(int &argc, char **argv);
 
-    void invokeDesktopProcess();
     void initTrash();
 
 private:

session/processmanager.cpp

@@ -22,17 +22,12 @@
 
 #include <QCoreApplication>
 #include <QStandardPaths>
-#include <QFileInfoList>
-#include <QFileInfo>
 #include <QSettings>
 #include <QDebug>
 #include <QProcessEnvironment>
 #include <QTimer>
-#include <QThread>
 #include <QDir>
 #include <QDBusConnectionInterface>
-#include <QDBusInterface>
-#include <QDBusPendingCall>
 #include <QDBusReply>
 #include <QDBusServiceWatcher>
 
@@ -86,9 +81,33 @@ void ProcessManager::startAfterKWinReady()
         m_kwinWatcher = nullptr;
     }
 
-    // The services daemon owns the Cutefish settings D-Bus service and
-    // starts the desktop components after that service is ready.
+    // Start the desktop after the services daemon has registered its D-Bus
+    // service so its theme and input backends are available to the shell.
+    const QString serviceName = QStringLiteral("com.cutefish.Services");
+    const auto servicesReady = [this]() {
+        if (m_servicesWatcher) {
+            m_servicesWatcher->deleteLater();
+            m_servicesWatcher = nullptr;
+        }
+        startDesktopProcess();
+    };
+
+    m_servicesWatcher = new QDBusServiceWatcher(serviceName,
+                                                QDBusConnection::sessionBus(),
+                                                QDBusServiceWatcher::WatchForRegistration,
+                                                this);
+    connect(m_servicesWatcher, &QDBusServiceWatcher::serviceRegistered,
+            this, [servicesReady](const QString &) {
+        servicesReady();
+    });
+
     startDaemonProcess();
+
+    if (QDBusConnectionInterface *interface = QDBusConnection::sessionBus().interface()) {
+        const QDBusReply<bool> reply = interface->isServiceRegistered(serviceName);
+        if (reply.isValid() && reply.value())
+            servicesReady();
+    }
 }
 
 void ProcessManager::logout()
@@ -133,9 +152,6 @@ void ProcessManager::startDesktopProcess()
 
     m_desktopStarted = true;
 
-    // Start the desktop after the services daemon has initialized its theme module.
-    // In the way, there will be no problem that desktop and launcher can't get wallpaper.
-
     QList<QPair<QString, QStringList>> list;
     // Desktop components
     // The status bar, dock, launcher, desktop and notifications are one process now.
@@ -184,8 +200,7 @@ void ProcessManager::startDesktopProcess()
 void ProcessManager::startDaemonProcess()
 {
     QList<QPair<QString, QStringList>> list;
-    // This daemon registers com.cutefish.Services and triggers startup of
-    // the desktop components once the service is available.
+    // This daemon provides the services used by the desktop components.
     list << qMakePair(QString("cutefish-services"), QStringList());
 
     for (QPair<QString, QStringList> pair : list) {

session/processmanager.h

@@ -49,6 +49,7 @@ private:
 private:
     Application *m_app;
     QDBusServiceWatcher *m_kwinWatcher = nullptr;
+    QDBusServiceWatcher *m_servicesWatcher = nullptr;
     bool m_kwinReady = false;
     bool m_desktopStarted = false;
     QMap<QString, QProcess *> m_systemProcess;