view: forbid mode change if cursor target

Making a floating view tiled during a resize breaks things badly.

river/InputManager.zig

@@ -26,6 +26,7 @@ const util = @import("util.zig");
 
 const Seat = @import("Seat.zig");
 const Server = @import("Server.zig");
+const View = @import("View.zig");
 
 const default_seat_name = "default";
 
@@ -101,6 +102,18 @@ pub fn inputAllowed(self: Self, wlr_surface: *c.wlr_surface) bool {
         true;
 }
 
+pub fn isCursorActionTarget(self: Self, view: *View) bool {
+    var it = self.seats.first;
+    return while (it) |node| : (it = node.next) {
+        const seat = &node.data;
+        switch (seat.cursor.mode) {
+            .passthrough => {},
+            .move => |data| if (data.view == view) break true,
+            .resize => |data| if (data.view == view) break true,
+        }
+    } else false;
+}
+
 fn handleInhibitActivate(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void {
     const self = @fieldParentPtr(Self, "listen_inhibit_activate", listener.?);