compositor: rework touch focus

In the wl_seat conversion, struct wl_touch got fields for the focused
surface and the client resource for the input device being focused.
However, the conversion was incomplete: the old fields
weston_seat::touch_focus* we still used by the event dispatching code,
but the new code never set them. Therefore no touch events were ever
sent.

From weston_seat, remove the fields touch_focus, touch_focus_listener,
touch_focus_resource, and touch_focus_resource_listener. They are
replaced by the corresponding fields and listeners from struct
wl_touch.

While doing this, fix touch_set_focus().

If touch_set_focus() was called first with surface A, and then with
surface B, without being called with NULL in between, it would corrupt
the destroy_signal list. It was equivalent of calling wl_signal_add()
for different signal sources with the same listener without removing in
between.

Now, touch_set_focus() first removes focus and listeners, and then
attempts to assign focus if requested. If the target client has not
subscribed for touch events, the touch focus will now be NULL.
Before this patch, the touch focus was left to the previous surface.

NOTE: this patch depends on the patch "server: add lose_touch_focus()"
for Wayland.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>

src/compositor.c

@@ -2060,33 +2060,20 @@ notify_keyboard_focus_out(struct wl_seat *seat)
 	wl_keyboard_end_grab(ws->seat.keyboard);
 }
 
-static void
-lose_touch_focus_resource(struct wl_listener *listener, void *data)
-{
-	struct weston_seat *seat = container_of(listener, struct weston_seat,
-						touch_focus_resource_listener);
-
-	seat->touch_focus_resource = NULL;
-}
-
-static void
-lose_touch_focus(struct wl_listener *listener, void *data)
-{
-	struct weston_seat *seat = container_of(listener, struct weston_seat,
-						touch_focus_listener);
-
-	seat->touch_focus = NULL;
-}
-
 static void
 touch_set_focus(struct weston_seat *ws, struct wl_surface *surface)
 {
 	struct wl_seat *seat = &ws->seat;
 	struct wl_resource *resource;
 
-	if (ws->touch_focus == surface)
+	if (seat->touch->focus == surface)
 		return;
 
+	if (seat->touch->focus_resource)
+		wl_list_remove(&seat->touch->focus_listener.link);
+	seat->touch->focus = NULL;
+	seat->touch->focus_resource = NULL;
+
 	if (surface) {
 		resource =
 			find_resource_for_client(&seat->touch->resource_list,
@@ -2096,23 +2083,10 @@ touch_set_focus(struct weston_seat *ws, struct wl_surface *surface)
 			return;
 		}
 
-		ws->touch_focus_resource_listener.notify =
-			lose_touch_focus_resource;
-		wl_signal_add(&resource->destroy_signal,
-			      &ws->touch_focus_resource_listener);
-		ws->touch_focus_listener.notify = lose_touch_focus;
-		wl_signal_add(&surface->resource.destroy_signal,
-			       &ws->touch_focus_listener);
-
 		seat->touch->focus = surface;
 		seat->touch->focus_resource = resource;
-	} else {
-		if (seat->touch->focus)
-			wl_list_remove(&ws->touch_focus_listener.link);
-		if (seat->touch->focus_resource)
-			wl_list_remove(&ws->touch_focus_resource_listener.link);
-		seat->touch->focus = NULL;
-		seat->touch->focus_resource = NULL;
+		wl_signal_add(&resource->destroy_signal,
+			      &seat->touch->focus_listener);
 	}
 }
 
@@ -2146,33 +2120,33 @@ notify_touch(struct wl_seat *seat, uint32_t time, int touch_id,
 		if (ws->num_tp == 1) {
 			es = weston_compositor_pick_surface(ec, x, y, &sx, &sy);
 			touch_set_focus(ws, &es->surface);
-		} else if (ws->touch_focus) {
-			es = (struct weston_surface *) ws->touch_focus;
+		} else if (seat->touch->focus) {
+			es = (struct weston_surface *)seat->touch->focus;
 			weston_surface_from_global_fixed(es, x, y, &sx, &sy);
 		}
 
-		if (ws->touch_focus_resource && ws->touch_focus)
-			wl_touch_send_down(ws->touch_focus_resource,
+		if (seat->touch->focus_resource && seat->touch->focus)
+			wl_touch_send_down(seat->touch->focus_resource,
 					   serial, time,
-					   &ws->touch_focus->resource,
+					   &seat->touch->focus->resource,
 					   touch_id, sx, sy);
 		break;
 	case WL_TOUCH_MOTION:
-		es = (struct weston_surface *) ws->touch_focus;
+		es = (struct weston_surface *)seat->touch->focus;
 		if (!es)
 			break;
 
 		weston_surface_from_global_fixed(es, x, y, &sx, &sy);
-		if (ws->touch_focus_resource)
-			wl_touch_send_motion(ws->touch_focus_resource,
+		if (seat->touch->focus_resource)
+			wl_touch_send_motion(seat->touch->focus_resource,
 					     time, touch_id, sx, sy);
 		break;
 	case WL_TOUCH_UP:
 		weston_compositor_idle_release(ec);
 		ws->num_tp--;
 
-		if (ws->touch_focus_resource)
-			wl_touch_send_up(ws->touch_focus_resource,
+		if (seat->touch->focus_resource)
+			wl_touch_send_up(seat->touch->focus_resource,
 					 serial, time, touch_id);
 		if (ws->num_tp == 0)
 			touch_set_focus(ws, NULL);

src/compositor.h

@@ -224,10 +224,6 @@ struct weston_seat {
 	struct wl_listener saved_kbd_focus_listener;
 
 	uint32_t num_tp;
-	struct wl_surface *touch_focus;
-	struct wl_listener touch_focus_listener;
-	struct wl_resource *touch_focus_resource;
-	struct wl_listener touch_focus_resource_listener;
 
 	struct wl_listener new_drag_icon_listener;