[gtk+] device: Fix dispose

[Carlos Garnacho <carlosg src gnome org>]

commit cc2e77295ef3c1acc81ccbe45e1cf063d45b9058
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Nov 24 17:53:41 2015 +0100

    device: Fix dispose
    
    The way master devices detach from their other master counterpart is
    vulnerable to infinite recursion due to the way we first recurse on
    the other device before clearing the pointer, this may happen if
    that last reference to the other master device is held by the
    device->associated field.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=732742

 gdk/gdkdevice.c |   17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)
---
diff --git a/gdk/gdkdevice.c b/gdk/gdkdevice.c
index a1a59d2..0e325d6 100644
--- a/gdk/gdkdevice.c
+++ b/gdk/gdkdevice.c
@@ -323,17 +323,20 @@ static void
 gdk_device_dispose (GObject *object)
 {
   GdkDevice *device = GDK_DEVICE (object);
+  GdkDevice *associated = device->associated;
 
-  if (device->type == GDK_DEVICE_TYPE_SLAVE)
-    _gdk_device_remove_slave (device->associated, device);
+  if (associated && device->type == GDK_DEVICE_TYPE_SLAVE)
+    _gdk_device_remove_slave (associated, device);
 
-  if (device->associated)
+  if (associated)
     {
-      if (device->type == GDK_DEVICE_TYPE_MASTER)
-        _gdk_device_set_associated_device (device->associated, NULL);
-
-      g_object_unref (device->associated);
       device->associated = NULL;
+
+      if (device->type == GDK_DEVICE_TYPE_MASTER &&
+          associated->associated == device)
+        _gdk_device_set_associated_device (associated, NULL);
+
+      g_object_unref (associated);
     }
 
   G_OBJECT_CLASS (gdk_device_parent_class)->dispose (object);