[PATCH weston 17/18] xwayland: Fix the race condition when mapping a surface

[ppaalanen at gmail.com]

From: Louis-Francis Ratté-Boulianne <lfrb at collabora.com>

Make sure XCB_MAP_NOTIFY has been received and the window id has been
set before mapping the shell surface. It fixes race condition making the
surface appears at wrong coordinates or with wrong size.
---
 src/xwayland/window-manager.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/xwayland/window-manager.c b/src/xwayland/window-manager.c
index 366f2e0..c2e680b 100644
--- a/src/xwayland/window-manager.c
+++ b/src/xwayland/window-manager.c
@@ -113,6 +113,7 @@ struct weston_wm_window {
 	int decorate;
 	int override_redirect;
 	int fullscreen;
+	int mapped;
 };
 
 static struct weston_wm_window *
@@ -121,6 +122,9 @@ get_wm_window(struct weston_surface *surface);
 static void
 weston_wm_window_schedule_repaint(struct weston_wm_window *window);
 
+static void
+xserver_map_shell_surface(struct weston_wm *wm, struct weston_wm_window *window);
+
 const char *
 get_atom_name(xcb_connection_t *c, xcb_atom_t atom)
 {
@@ -723,6 +727,14 @@ static void
 weston_wm_handle_map_notify(struct weston_wm *wm, xcb_generic_event_t *event)
 {
 	xcb_map_notify_event_t *map_notify = (xcb_map_notify_event_t *) event;
+	struct weston_wm_window *window;
+
+	window = hash_table_lookup(wm->window_hash, map_notify->window);
+
+	if (window->surface != NULL)
+		xserver_map_shell_surface(wm, window);
+	else
+		window->mapped = 1;
 
 	if (our_resource(wm, map_notify->window)) {
 			weston_log("XCB_MAP_NOTIFY (window %d, ours)\n",
@@ -915,6 +927,8 @@ weston_wm_window_create(struct weston_wm *wm,
 	window->override_redirect = override;
 	window->width = width;
 	window->height = height;
+	window->surface = NULL;
+	window->mapped = 0;
 
 	hash_table_insert(wm->window_hash, id, window);
 }
@@ -1874,7 +1888,9 @@ xserver_set_window_id(struct wl_client *client, struct wl_resource *resource,
 		      &window->surface_destroy_listener);
 
 	weston_wm_window_schedule_repaint(window);
-	xserver_map_shell_surface(wm, window);
+
+	if (window->mapped)
+		xserver_map_shell_surface(wm, window);
 }
 
 const struct xserver_interface xserver_implementation = {
-- 
1.8.1.5