[mutter] wayland/xdg-shell: Handle requests after toplevel was unmanaged

[Jonas Ådahl <jadahl src gnome org>]

commit 5fd0f62a62a194ffd8e64d177f389912a582f8e1
Author: Jonas Ådahl <jadahl gmail com>
Date:   Wed Jul 25 11:56:14 2018 +0200

    wayland/xdg-shell: Handle requests after toplevel was unmanaged
    
    A window can be unmanaged without asking the client to do it, for
    example as a side effect of a parent window being unmanaged, if the
    child window was a attached dialog.
    
    This means that the client might still make requests post updates to it
    after that it was unmapped. Handle this gracefully by NULL-checking the
    surface's MetaWindow pointer. We're not loosing any state due to this,
    as if the client wants to map the same surface again, it needs to either
    reassign it the toplevel role, or reset the xdg-toplevel, both resulting
    in all state being lost anyway.
    
    https://gitlab.gnome.org/GNOME/mutter/issues/240

 src/wayland/meta-wayland-xdg-shell.c | 80 ++++++++++++++++++++++++++++++------
 1 file changed, 67 insertions(+), 13 deletions(-)
---
diff --git a/src/wayland/meta-wayland-xdg-shell.c b/src/wayland/meta-wayland-xdg-shell.c
index 6bcaa59b0..f3cea9912 100644
--- a/src/wayland/meta-wayland-xdg-shell.c
+++ b/src/wayland/meta-wayland-xdg-shell.c
@@ -191,6 +191,11 @@ xdg_toplevel_set_parent (struct wl_client   *client,
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
   MetaWindow *transient_for = NULL;
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
   if (parent_resource)
     {
@@ -200,7 +205,7 @@ xdg_toplevel_set_parent (struct wl_client   *client,
       transient_for = parent_surface->window;
     }
 
-  meta_window_set_transient_for (surface->window, transient_for);
+  meta_window_set_transient_for (window, transient_for);
 }
 
 static void
@@ -209,11 +214,16 @@ xdg_toplevel_set_title (struct wl_client   *client,
                         const char         *title)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
   if (!g_utf8_validate (title, -1, NULL))
     title = "";
 
-  meta_window_set_title (surface->window, title);
+  meta_window_set_title (window, title);
 }
 
 static void
@@ -222,11 +232,16 @@ xdg_toplevel_set_app_id (struct wl_client   *client,
                          const char         *app_id)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
   if (!g_utf8_validate (app_id, -1, NULL))
     app_id = "";
 
-  meta_window_set_wm_class (surface->window, app_id, app_id);
+  meta_window_set_wm_class (window, app_id, app_id);
 }
 
 static void
@@ -239,15 +254,20 @@ xdg_toplevel_show_window_menu (struct wl_client   *client,
 {
   MetaWaylandSeat *seat = wl_resource_get_user_data (seat_resource);
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
   int monitor_scale;
 
+  window = surface->window;
+  if (!window)
+    return;
+
   if (!meta_wayland_seat_get_grab_info (seat, surface, serial, FALSE, NULL, NULL))
     return;
 
-  monitor_scale = surface->window->monitor->scale;
-  meta_window_show_menu (surface->window, META_WINDOW_MENU_WM,
-                         surface->window->buffer_rect.x + (x * monitor_scale),
-                         surface->window->buffer_rect.y + (y * monitor_scale));
+  monitor_scale = window->monitor->scale;
+  meta_window_show_menu (window, META_WINDOW_MENU_WM,
+                         window->buffer_rect.x + (x * monitor_scale),
+                         window->buffer_rect.y + (y * monitor_scale));
 }
 
 static void
@@ -258,8 +278,13 @@ xdg_toplevel_move (struct wl_client   *client,
 {
   MetaWaylandSeat *seat = wl_resource_get_user_data (seat_resource);
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
   float x, y;
 
+  window = surface->window;
+  if (!window)
+    return;
+
   if (!meta_wayland_seat_get_grab_info (seat, surface, serial, TRUE, &x, &y))
     return;
 
@@ -298,9 +323,14 @@ xdg_toplevel_resize (struct wl_client   *client,
 {
   MetaWaylandSeat *seat = wl_resource_get_user_data (seat_resource);
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
   gfloat x, y;
   MetaGrabOp grab_op;
 
+  window = surface->window;
+  if (!window)
+    return;
+
   if (!meta_wayland_seat_get_grab_info (seat, surface, serial, TRUE, &x, &y))
     return;
 
@@ -357,7 +387,11 @@ xdg_toplevel_set_maximized (struct wl_client   *client,
                             struct wl_resource *resource)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
-  MetaWindow *window = surface->window;
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
   meta_window_force_placement (window, TRUE);
   meta_window_maximize (window, META_MAXIMIZE_BOTH);
@@ -368,8 +402,13 @@ xdg_toplevel_unset_maximized (struct wl_client   *client,
                               struct wl_resource *resource)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
 
-  meta_window_unmaximize (surface->window, META_MAXIMIZE_BOTH);
+  window = surface->window;
+  if (!window)
+    return;
+
+  meta_window_unmaximize (window, META_MAXIMIZE_BOTH);
 }
 
 static void
@@ -378,6 +417,11 @@ xdg_toplevel_set_fullscreen (struct wl_client   *client,
                              struct wl_resource *output_resource)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
   if (output_resource)
     {
@@ -385,12 +429,12 @@ xdg_toplevel_set_fullscreen (struct wl_client   *client,
 
       if (output)
         {
-          meta_window_move_to_monitor (surface->window,
+          meta_window_move_to_monitor (window,
                                        output->logical_monitor->number);
         }
     }
 
-  meta_window_make_fullscreen (surface->window);
+  meta_window_make_fullscreen (window);
 }
 
 static void
@@ -398,8 +442,13 @@ xdg_toplevel_unset_fullscreen (struct wl_client   *client,
                                struct wl_resource *resource)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
-  meta_window_unmake_fullscreen (surface->window);
+  meta_window_unmake_fullscreen (window);
 }
 
 static void
@@ -407,8 +456,13 @@ xdg_toplevel_set_minimized (struct wl_client   *client,
                             struct wl_resource *resource)
 {
   MetaWaylandSurface *surface = surface_from_xdg_toplevel_resource (resource);
+  MetaWindow *window;
+
+  window = surface->window;
+  if (!window)
+    return;
 
-  meta_window_minimize (surface->window);
+  meta_window_minimize (window);
 }
 
 static const struct xdg_toplevel_interface meta_wayland_xdg_toplevel_interface = {