xwayland: Handle selection source going away without crashing

src/xwayland/selection.c

@@ -547,10 +547,28 @@ weston_wm_handle_xfixes_selection_notify(struct weston_wm *wm,
 {
 	xcb_xfixes_selection_notify_event_t *xfixes_selection_notify =
 		(xcb_xfixes_selection_notify_event_t *) event;
+	struct weston_compositor *compositor;
+	uint32_t serial;
 
 	printf("xfixes selection notify event: owner %d\n",
 	       xfixes_selection_notify->owner);
 
+	if (xfixes_selection_notify->owner == XCB_WINDOW_NONE) {
+		if (wm->selection_owner != wm->selection_window) {
+			/* A real X client selection went away, not our
+			 * proxy selection.  Clear the wayland selection. */
+			compositor = wm->server->compositor;
+			serial = wl_display_next_serial(compositor->wl_display);
+			wl_seat_set_selection(&compositor->seat->seat, NULL, serial);
+		}
+
+		wm->selection_owner = XCB_WINDOW_NONE;
+
+		return;
+	}
+
+	wm->selection_owner = xfixes_selection_notify->owner;
+
 	/* We have to use XCB_TIME_CURRENT_TIME when we claim the
 	 * selection, so grab the actual timestamp here so we can
 	 * answer TIMESTAMP conversion requests correctly. */
@@ -604,11 +622,18 @@ weston_wm_set_selection(struct wl_listener *listener, void *data)
 	const char **p, **end;
 	int has_text_plain = 0;
 
+	if (source == NULL) {
+		if (wm->selection_owner == wm->selection_window)
+			xcb_set_selection_owner(wm->conn,
+						XCB_ATOM_NONE,
+						wm->atom.clipboard,
+						wm->selection_timestamp);
+		return;
+	}
+
 	if (source->offer_interface == &data_offer_interface)
 		return;
 
-	fprintf(stderr, "set selection\n");
-
 	p = source->mime_types.data;
 	end = (const char **)
 		((char *) source->mime_types.data + source->mime_types.size);

src/xwayland/window-manager.c

@@ -906,7 +906,6 @@ weston_wm_handle_event(int fd, uint32_t mask, void *data)
 
 	while (event = xcb_poll_for_event(wm->conn), event != NULL) {
 		if (weston_wm_handle_selection_event(wm, event)) {
-			fprintf(stderr, "handled by selection code\n");
 			free(event);
 			count++;
 			continue;

src/xwayland/xwayland.h

@@ -62,6 +62,7 @@ struct weston_wm {
 	struct wl_listener activate_listener;
 
 	xcb_window_t selection_window;
+	xcb_window_t selection_owner;
 	int incr;
 	int data_source_fd;
 	struct wl_event_source *property_source;