[mutter] wayland/xdg-shell: Fix top-most check when grabbing

[Jonas Ådahl <jadahl src gnome org>]

commit 5d3b4f0134bdd84ee30648fb401bad7522d23cf1
Author: Jonas Ådahl <jadahl gmail com>
Date:   Wed Nov 15 16:02:03 2017 +0800

    wayland/xdg-shell: Fix top-most check when grabbing
    
    Move the top-most-popup correctness check to the finish_popup_setup()
    function after checking the serial. If we pass the serial check, we
    should have reached a state that if there are any popups they should be
    the one from the same client.
    
    Also avoid failing a client that correctly set the top-most popup at map
    time, but where at the time of processing the top most popup have
    already been dismissed by the compositor for some arbitrary reason.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=790358

 src/wayland/meta-wayland-xdg-shell.c |   30 ++++++++++++++----------------
 1 files changed, 14 insertions(+), 16 deletions(-)
---
diff --git a/src/wayland/meta-wayland-xdg-shell.c b/src/wayland/meta-wayland-xdg-shell.c
index 99fc9ac..5ca39b3 100644
--- a/src/wayland/meta-wayland-xdg-shell.c
+++ b/src/wayland/meta-wayland-xdg-shell.c
@@ -448,7 +448,6 @@ xdg_popup_grab (struct wl_client   *client,
     META_WAYLAND_XDG_POPUP (wl_resource_get_user_data (resource));
   MetaWaylandSeat *seat = wl_resource_get_user_data (seat_resource);
   MetaWaylandSurface *parent_surface;
-  MetaWaylandSurface *top_popup;
 
   parent_surface = xdg_popup->setup.parent_surface;
   if (!parent_surface)
@@ -459,21 +458,6 @@ xdg_popup_grab (struct wl_client   *client,
       return;
     }
 
-  top_popup = meta_wayland_pointer_get_top_popup (seat->pointer);
-  if ((top_popup == NULL &&
-       !META_IS_WAYLAND_XDG_SURFACE (parent_surface->role)) ||
-      (top_popup != NULL && parent_surface != top_popup))
-    {
-      MetaWaylandXdgSurface *xdg_surface = META_WAYLAND_XDG_SURFACE (xdg_popup);
-      struct wl_resource *xdg_shell_resource =
-        meta_wayland_xdg_surface_get_shell_resource (xdg_surface);
-
-      wl_resource_post_error (xdg_shell_resource,
-                              ZXDG_SHELL_V6_ERROR_NOT_THE_TOPMOST_POPUP,
-                              "parent not top most surface");
-      return;
-    }
-
   xdg_popup->setup.grab_seat = seat;
   xdg_popup->setup.grab_serial = serial;
 }
@@ -794,7 +778,10 @@ scale_placement_rule (MetaPlacementRule  *placement_rule,
 static void
 finish_popup_setup (MetaWaylandXdgPopup *xdg_popup)
 {
+  MetaWaylandXdgSurface *xdg_surface = META_WAYLAND_XDG_SURFACE (xdg_popup);
   MetaWaylandSurfaceRole *surface_role = META_WAYLAND_SURFACE_ROLE (xdg_popup);
+  struct wl_resource *xdg_shell_resource =
+    meta_wayland_xdg_surface_get_shell_resource (xdg_surface);
   MetaWaylandSurface *surface =
     meta_wayland_surface_role_get_surface (surface_role);
   MetaWaylandSurface *parent_surface;
@@ -813,11 +800,22 @@ finish_popup_setup (MetaWaylandXdgPopup *xdg_popup)
 
   if (seat)
     {
+      MetaWaylandSurface *top_popup;
+
       if (!meta_wayland_seat_can_popup (seat, serial))
         {
           zxdg_popup_v6_send_popup_done (xdg_popup->resource);
           return;
         }
+
+      top_popup = meta_wayland_pointer_get_top_popup (seat->pointer);
+      if (top_popup && parent_surface != top_popup)
+        {
+          wl_resource_post_error (xdg_shell_resource,
+                                  ZXDG_SHELL_V6_ERROR_NOT_THE_TOPMOST_POPUP,
+                                  "parent not top most surface");
+          return;
+        }
     }
 
   xdg_popup->parent_surface = parent_surface;