xwm: use always a valid 'primary view' for an X window

The xwm gets a primary view for a X window using the get_primary_view
vfunc of the shell_interface struct. Storing it is dangerous though
because it doesn't listen for its destruction so it may end up using the
old stored view pointer after that view was freed, or after the primary
view for that window was changed to another one.

Fetch the primary view just before using it every time and try to not
abuse this 'primary view' concept which may map badly to some shells:
iterate over all the views instead when it makes sense.

Tested-by: Benoit Gschwind <gschwind@gnu-log.net>
Reviewed-by: Derek Foreman <derekf@osg.samsung.com>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>

xwayland/window-manager.c

@@ -132,7 +132,6 @@ struct weston_wm_window {
 	uint32_t surface_id;
 	struct weston_surface *surface;
 	struct shell_surface *shsurf;
-	struct weston_view *view;
 	struct wl_listener surface_destroy_listener;
 	struct wl_event_source *repaint_source;
 	struct wl_event_source *configure_source;
@@ -816,18 +815,27 @@ weston_wm_window_transform(struct wl_listener *listener, void *data)
 	struct weston_wm_window *window = get_wm_window(surface);
 	struct weston_wm *wm =
 		container_of(listener, struct weston_wm, transform_listener);
+	struct weston_view *view;
+	struct weston_shell_interface *shell_interface =
+		&wm->server->compositor->shell_interface;
 	uint32_t mask, values[2];
 
-	if (!window || !wm)
+	if (!window || !wm || !window->shsurf)
 		return;
 
-	if (!window->view || !weston_view_is_mapped(window->view))
+	if (!shell_interface->get_primary_view)
 		return;
 
-	if (window->x != window->view->geometry.x ||
-	    window->y != window->view->geometry.y) {
-		values[0] = window->view->geometry.x;
-		values[1] = window->view->geometry.y;
+	view = shell_interface->get_primary_view(shell_interface->shell,
+	                                         window->shsurf);
+
+	if (!view || !weston_view_is_mapped(view))
+		return;
+
+	if (window->x != view->geometry.x ||
+	    window->y != view->geometry.y) {
+		values[0] = view->geometry.x;
+		values[1] = view->geometry.y;
 		mask = XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y;
 
 		xcb_configure_window(wm->conn, window->frame_id, mask, values);
@@ -1049,7 +1057,6 @@ weston_wm_handle_unmap_notify(struct weston_wm *wm, xcb_generic_event_t *event)
 		wl_list_remove(&window->surface_destroy_listener.link);
 	window->surface = NULL;
 	window->shsurf = NULL;
-	window->view = NULL;
 
 	weston_wm_window_set_wm_state(window, ICCCM_WITHDRAWN_STATE);
 	weston_wm_window_set_virtual_desktop(window, -1);
@@ -1069,6 +1076,7 @@ weston_wm_window_draw_decoration(void *data)
 	struct weston_shell_interface *shell_interface =
 		&wm->server->compositor->shell_interface;
 	uint32_t flags = 0;
+	struct weston_view *view;
 
 	weston_wm_window_read_properties(window);
 
@@ -1110,8 +1118,8 @@ weston_wm_window_draw_decoration(void *data)
 						  window->width + 2,
 						  window->height + 2);
 		}
-		if (window->view)
-			weston_view_geometry_dirty(window->view);
+		wl_list_for_each(view, &window->surface->views, surface_link)
+			weston_view_geometry_dirty(view);
 
 		pixman_region32_fini(&window->surface->pending.input);
 
@@ -1137,6 +1145,7 @@ static void
 weston_wm_window_schedule_repaint(struct weston_wm_window *window)
 {
 	struct weston_wm *wm = window->wm;
+	struct weston_view *view;
 	int width, height;
 
 	if (window->frame_id == XCB_WINDOW_NONE) {
@@ -1149,8 +1158,8 @@ weston_wm_window_schedule_repaint(struct weston_wm_window *window)
 				pixman_region32_init_rect(&window->surface->pending.opaque, 0, 0,
 							  width, height);
 			}
-			if (window->view)
-				weston_view_geometry_dirty(window->view);
+			wl_list_for_each(view, &window->surface->views, surface_link)
+				weston_view_geometry_dirty(view);
 		}
 		return;
 	}
@@ -1517,7 +1526,6 @@ surface_destroy(struct wl_listener *listener, void *data)
 	 * Don't try to use it later. */
 	window->shsurf = NULL;
 	window->surface = NULL;
-	window->view = NULL;
 }
 
 static void
@@ -2524,9 +2532,6 @@ xserver_map_shell_surface(struct weston_wm_window *window,
 	if (!shell_interface->create_shell_surface)
 		return;
 
-	if (!shell_interface->get_primary_view)
-		return;
-
 	if (window->surface->configure) {
 		weston_log("warning, unexpected in %s: "
 			   "surface's configure hook is already set.\n",
@@ -2538,8 +2543,6 @@ xserver_map_shell_surface(struct weston_wm_window *window,
 		shell_interface->create_shell_surface(shell_interface->shell,
 						      window->surface,
 						      &shell_client);
-	window->view = shell_interface->get_primary_view(shell_interface->shell,
-							 window->shsurf);
 
 	if (window->name)
 		shell_interface->set_title(window->shsurf, window->name);