From df2c26e3d9a2c3e95e0bd3def290c564ff62a278 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Gr=C3=A4=C3=9Flin?= <mgraesslin@kde.org>
Date: Thu, 14 Apr 2016 08:51:16 +0200
Subject: [PATCH] Only start Xwayland server if Compositor created a Scene

So far if the Scene creation failed kwin_wayland went into a shutdown,
but didn't succeed because the thread to start Xwayland was already
running: it froze.

This change introduces a new signal in Compositor: sceneCreated. The
startup of Xwayland is bound to this signal. If it gets fired KWin can
startup Xwayland. If it does not get fired, KWin terminates correctly.
---
 composite.cpp    | 1 +
 composite.h      | 1 +
 main_wayland.cpp | 5 +++--
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/composite.cpp b/composite.cpp
index dab48f4caf..66ac47f320 100644
--- a/composite.cpp
+++ b/composite.cpp
@@ -278,6 +278,7 @@ void Compositor::slotCompositingOptionsInitialized()
         }
         return;
     }
+    emit sceneCreated();
 
     if (Workspace::self()) {
         startupWithWorkspace();
diff --git a/composite.h b/composite.h
index fc0ddd5288..50134cb18f 100644
--- a/composite.h
+++ b/composite.h
@@ -186,6 +186,7 @@ public Q_SLOTS:
 Q_SIGNALS:
     void compositingToggled(bool active);
     void aboutToDestroy();
+    void sceneCreated();
 
 protected:
     void timerEvent(QTimerEvent *te);
diff --git a/main_wayland.cpp b/main_wayland.cpp
index c9ee426150..6bcbe182ae 100644
--- a/main_wayland.cpp
+++ b/main_wayland.cpp
@@ -18,6 +18,7 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************/
 #include "main_wayland.h"
+#include "composite.h"
 #include "workspace.h"
 #include <config-kwin.h>
 // kwin
@@ -152,8 +153,7 @@ void ApplicationWayland::continueStartupWithScreens()
         return;
     }
     createCompositor();
-
-    startXwaylandServer();
+    connect(Compositor::self(), &Compositor::sceneCreated, this, &ApplicationWayland::startXwaylandServer);
 }
 
 void ApplicationWayland::continueStartupWithX()
@@ -280,6 +280,7 @@ void ApplicationWayland::createX11Connection()
 
 void ApplicationWayland::startXwaylandServer()
 {
+    disconnect(Compositor::self(), &Compositor::sceneCreated, this, &ApplicationWayland::startXwaylandServer);
     int pipeFds[2];
     if (pipe(pipeFds) != 0) {
         std::cerr << "FATAL ERROR failed to create pipe to start Xwayland " << std::endl;