Compositor xdg-decoration: Fix crash when clients disconnect

If clients were disconnected without shutting down nicely, e.g. if Qt clients
were terminated with SIGINT, then QWaylandXdgToplevelDecorationV1 would be
deleted before its Wayland resource, causing a crash in the resource destroy
handler.

This switches to a raw pointer in the toplevel, which is now cleared when the
decoration is deleted. Deletion order is also ensured by conditionally destroying
the resource in the toplevel destructor.

Warnings are also printed when clients destroy objects in the wrong order
(protocol errors).

Change-Id: I8c24becb82e298e93cd45d70a004d8d23ead382b
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/compositor/extensions/qwaylandxdgdecorationv1_p.h b/src/compositor/extensions/qwaylandxdgdecorationv1_p.h
index 4c6c46334..3d181a919 100644
--- a/src/compositor/extensions/qwaylandxdgdecorationv1_p.h
+++ b/src/compositor/extensions/qwaylandxdgdecorationv1_p.h
@@ -83,6 +83,7 @@ public:
     explicit QWaylandXdgToplevelDecorationV1(QWaylandXdgToplevel *toplevel,
                                              QWaylandXdgDecorationManagerV1 *manager,
                                              wl_client *client, int id);
+    ~QWaylandXdgToplevelDecorationV1() override;
 
     DecorationMode configuredMode() const { return m_configuredMode; }
     void sendConfigure(DecorationMode mode);