seat: keep track of serials that are allowed to steal keyboard focus

src/client.rs

@@ -175,6 +175,7 @@ impl Clients {
                 slf,
             )),
             wire_scale: Default::default(),
+            focus_stealing_serial: Default::default(),
         });
         track!(data, data);
         let display = Rc::new(WlDisplay::new(&data));
@@ -286,6 +287,7 @@ pub struct Client {
     pub activation_tokens: RefCell<VecDeque<ActivationToken>>,
     pub commit_timelines: Rc<CommitTimelines>,
     pub wire_scale: Cell<Option<i32>>,
+    pub focus_stealing_serial: Cell<Option<u64>>,
 }
 
 pub const NUM_CACHED_SERIAL_RANGES: usize = 64;

src/ifs/wl_seat.rs

@@ -1041,6 +1041,18 @@ impl WlSeatGlobal {
             ei_seat.regions_changed();
         });
     }
+
+    #[expect(dead_code)]
+    pub fn handle_focus_request(self: &Rc<Self>, client: &Client, node: Rc<dyn Node>, serial: u64) {
+        let Some(max_serial) = client.focus_stealing_serial.get() else {
+            return;
+        };
+        let serial = serial.min(max_serial);
+        if serial <= self.keyboard_node_serial.get() {
+            return;
+        }
+        self.focus_node_with_serial(node, serial);
+    }
 }
 
 impl CursorUserOwner for WlSeatGlobal {

src/ifs/wl_seat/event_handling.rs

@@ -1150,7 +1150,10 @@ impl WlSeatGlobal {
     ) {
         let (state, pressed) = match state {
             KeyState::Released => (wl_pointer::RELEASED, false),
-            KeyState::Pressed => (wl_pointer::PRESSED, true),
+            KeyState::Pressed => {
+                surface.client.focus_stealing_serial.set(Some(serial));
+                (wl_pointer::PRESSED, true)
+            }
         };
         let time = (time_usec / 1000) as u32;
         self.surface_pointer_event(Version::ALL, surface, |p| {
@@ -1372,6 +1375,7 @@ impl WlSeatGlobal {
         y: Fixed,
     ) {
         let serial = surface.client.next_serial();
+        surface.client.focus_stealing_serial.set(Some(serial));
         let time = (time_usec / 1000) as _;
         self.surface_touch_event(Version::ALL, surface, |t| {
             t.send_down(serial, time, surface.id, id, x, y)

src/ifs/wl_seat/tablet/tool.rs

@@ -211,6 +211,7 @@ impl TabletTool {
             tool.send_frame(time);
         });
         if state == ToolButtonState::Pressed {
+            n.client.focus_stealing_serial.set(Some(serial.get()));
             if let Some(node) = n.get_focus_node(self.tablet.seat.id) {
                 self.tablet.seat.focus_node_with_serial(node, serial.get());
             }
@@ -259,6 +260,7 @@ impl TabletTool {
         });
         if let Some(changes) = changes {
             if changes.down == Some(true) {
+                n.client.focus_stealing_serial.set(Some(serial.get()));
                 if let Some(node) = n.get_focus_node(self.tablet.seat.id) {
                     self.tablet.seat.focus_node_with_serial(node, serial.get());
                 }