touch: make cancel functions take a wlr_seat_client

The surface argument is only used to obtain a wlr_seat_client and
semantically makes no sense. The wl_touch.cancel event applies to all
touch points and all surfaces of a client.

I decided to make the functions accept a wlr_seat_client rather than a
wl_client as it is directly available in the wlr_touch_point struct and
simplifies the implementation.

include/wlr/types/wlr_seat.h

@@ -137,7 +137,7 @@ struct wlr_touch_grab_interface {
 	void (*cancel)(struct wlr_seat_touch_grab *grab);
 	// Send wl_touch.cancel
 	void (*wl_cancel)(struct wlr_seat_touch_grab *grab,
-			struct wlr_surface *surface);
+			struct wlr_seat_client *seat_client);
 };
 
 /**
@@ -632,11 +632,12 @@ void wlr_seat_touch_send_motion(struct wlr_seat *seat, uint32_t time_msec,
 
 /**
  * Notify the seat that this is a global gesture and the client should cancel
- * processing it. The event will go to the client for the surface given.
+ * processing it. The event will go to the client given.
  * This function does not respect touch grabs: you probably want
  * wlr_seat_touch_notify_cancel() instead.
  */
-void wlr_seat_touch_send_cancel(struct wlr_seat *seat, struct wlr_surface *surface);
+void wlr_seat_touch_send_cancel(struct wlr_seat *seat,
+		struct wlr_seat_client *seat_client);
 
 void wlr_seat_touch_send_frame(struct wlr_seat *seat);
 
@@ -669,7 +670,7 @@ void wlr_seat_touch_notify_motion(struct wlr_seat *seat, uint32_t time_msec,
  * cancel processing it. Defers to any grab of the touch device.
  */
 void wlr_seat_touch_notify_cancel(struct wlr_seat *seat,
-		struct wlr_surface *surface);
+		struct wlr_seat_client *seat_client);
 
 void wlr_seat_touch_notify_frame(struct wlr_seat *seat);
 

types/seat/wlr_seat_touch.c

@@ -40,8 +40,8 @@ static void default_touch_cancel(struct wlr_seat_touch_grab *grab) {
 }
 
 static void default_touch_wl_cancel(struct wlr_seat_touch_grab *grab,
-		struct wlr_surface *surface) {
+		struct wlr_seat_client *seat_client) {
-	wlr_seat_touch_send_cancel(grab->seat, surface);
+	wlr_seat_touch_send_cancel(grab->seat, seat_client);
 }
 
 const struct wlr_touch_grab_interface default_touch_grab_impl = {
@@ -242,17 +242,12 @@ void wlr_seat_touch_notify_frame(struct wlr_seat *seat) {
 }
 
 void wlr_seat_touch_notify_cancel(struct wlr_seat *seat,
-		struct wlr_surface *surface) {
+		struct wlr_seat_client *seat_client) {
 	struct wlr_seat_touch_grab *grab = seat->touch_state.grab;
 	if (grab->interface->wl_cancel) {
-		grab->interface->wl_cancel(grab, surface);
+		grab->interface->wl_cancel(grab, seat_client);
 	}
 
-	struct wl_client *client = wl_resource_get_client(surface->resource);
-	struct wlr_seat_client *seat_client = wlr_seat_client_for_wl_client(seat, client);
-	if (seat_client == NULL) {
-		return;
-	}
 	struct wlr_touch_point *point, *tmp;
 	wl_list_for_each_safe(point, tmp, &seat->touch_state.touch_points, link) {
 		if (point->client == seat_client) {
@@ -399,13 +394,8 @@ void wlr_seat_touch_send_frame(struct wlr_seat *seat) {
 	}
 }
 
-void wlr_seat_touch_send_cancel(struct wlr_seat *seat, struct wlr_surface *surface) {
+void wlr_seat_touch_send_cancel(struct wlr_seat *seat,
-	struct wl_client *client = wl_resource_get_client(surface->resource);
+		struct wlr_seat_client *seat_client) {
-	struct wlr_seat_client *seat_client = wlr_seat_client_for_wl_client(seat, client);
-	if (seat_client == NULL) {
-		return;
-	}
-
 	struct wl_resource *resource;
 	wl_resource_for_each(resource, &seat_client->touches) {
 		if (seat_client_from_touch_resource(resource) == NULL) {