Allow non keyboard_interactive layer surfaces to be focused

Layer surfaces can now receive keyboard input while focused. This narrows the gap
between regular views and non-keyboard exclusive layer surfaces which now handle focus
the same way.

This also simultaneously fixes a bug that allowed views under a
keyboard exclusive layer to be resized, moved, and focused.

sway/input/seatop_default.c

@@ -369,7 +369,11 @@ static void handle_button(struct sway_seat *seat, uint32_t time_msec,
 	struct wlr_layer_surface_v1 *layer;
 	if (surface &&
 			(layer = wlr_layer_surface_v1_try_from_wlr_surface(surface))) {
-		if (layer->current.keyboard_interactive) {
+		if (layer->current.keyboard_interactive
+				|| !(seat->focused_layer
+					&& seat->focused_layer->current.keyboard_interactive
+					&& seat->focused_layer != layer)) {
+			seat_set_focus(seat, NULL);
 			seat_set_focus_layer(seat, layer);
 			transaction_commit_dirty();
 		}
@@ -380,6 +384,12 @@ static void handle_button(struct sway_seat *seat, uint32_t time_msec,
 		return;
 	}
 
+	// Don't change focus and don't send any inputs if there's a focused layer
+	// with keyboard exclusivity
+	if (seat->focused_layer && seat->focused_layer->current.keyboard_interactive) {
+		return;
+	}
+
 	// Handle tiling resize via border
 	if (cont && resize_edge && button == BTN_LEFT &&
 			state == WLR_BUTTON_PRESSED && !is_floating) {
@@ -443,6 +453,9 @@ static void handle_button(struct sway_seat *seat, uint32_t time_msec,
 			}
 		}
 
+		// Move the focus from the layer non-keyboard exclusive layer
+		seat_set_focus_layer(seat, NULL);
+
 		seat_set_focus(seat, node);
 		transaction_commit_dirty();
 	}
@@ -565,6 +578,11 @@ static void check_focus_follows_mouse(struct sway_seat *seat,
 		return;
 	}
 
+	// Prevents the layer from losing focus if it has keyboard exclusivity
+	if (seat->focused_layer && seat->focused_layer->current.keyboard_interactive) {
+		return;
+	}
+
 	// This is where we handle the common case. We don't want to focus inactive
 	// tabs, hence the view_is_visible check.
 	if (node_is_view(hovered_node) &&
@@ -575,6 +593,9 @@ static void check_focus_follows_mouse(struct sway_seat *seat,
 		// But if focus_follows_mouse is "always", we do.
 		if (hovered_node != e->previous_node ||
 				config->focus_follows_mouse == FOLLOWS_ALWAYS) {
+			// Move the focus from the layer non-keyboard exclusive layer
+			seat_set_focus_layer(seat, NULL);
+
 			seat_set_focus(seat, hovered_node);
 			transaction_commit_dirty();
 		}