On Wayland, send Focused(false) once seats left

Given that we merge all the seats, we should consider that window
is not focused once all seats wl_keyboards are no longer present.

We use seats instead of keyboards to track focus to protect against
wl_keyboard::leave not being delivered when removing the seat
(usually it's not the case though).

Fixes: #3376

src/platform_impl/linux/wayland/seat/keyboard/mod.rs

@@ -61,8 +61,13 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                 let window_id = wayland::make_wid(&surface);
 
                 // Mark the window as focused.
-                match state.windows.get_mut().get(&window_id) {
-                    Some(window) => window.lock().unwrap().set_has_focus(true),
+                let was_unfocused = match state.windows.get_mut().get(&window_id) {
+                    Some(window) => {
+                        let mut window = window.lock().unwrap();
+                        let was_unfocused = !window.has_focus();
+                        window.add_seat_focus(data.seat.id());
+                        was_unfocused
+                    }
                     None => return,
                 };
 
@@ -73,13 +78,15 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                     keyboard_state.loop_handle.remove(token);
                 }
 
-                // The keyboard focus is considered as general focus.
-                state
-                    .events_sink
-                    .push_window_event(WindowEvent::Focused(true), window_id);
-
                 *data.window_id.lock().unwrap() = Some(window_id);
 
+                // The keyboard focus is considered as general focus.
+                if was_unfocused {
+                    state
+                        .events_sink
+                        .push_window_event(WindowEvent::Focused(true), window_id);
+                }
+
                 // HACK: this is just for GNOME not fixing their ordering issue of modifiers.
                 if std::mem::take(&mut seat_state.modifiers_pending) {
                     state.events_sink.push_window_event(
@@ -101,24 +108,30 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
 
                 // NOTE: The check whether the window exists is essential as we might get a
                 // nil surface, regardless of what protocol says.
-                match state.windows.get_mut().get(&window_id) {
-                    Some(window) => window.lock().unwrap().set_has_focus(false),
+                let focused = match state.windows.get_mut().get(&window_id) {
+                    Some(window) => {
+                        let mut window = window.lock().unwrap();
+                        window.remove_seat_focus(&data.seat.id());
+                        window.has_focus()
+                    }
                     None => return,
                 };
 
-                // Notify that no modifiers are being pressed.
-                state.events_sink.push_window_event(
-                    WindowEvent::ModifiersChanged(ModifiersState::empty().into()),
-                    window_id,
-                );
-
                 // We don't need to update it above, because the next `Enter` will overwrite
                 // anyway.
                 *data.window_id.lock().unwrap() = None;
 
-                state
-                    .events_sink
-                    .push_window_event(WindowEvent::Focused(false), window_id);
+                if !focused {
+                    // Notify that no modifiers are being pressed.
+                    state.events_sink.push_window_event(
+                        WindowEvent::ModifiersChanged(ModifiersState::empty().into()),
+                        window_id,
+                    );
+
+                    state
+                        .events_sink
+                        .push_window_event(WindowEvent::Focused(false), window_id);
+                }
             }
             WlKeyboardEvent::Key {
                 key,

src/platform_impl/linux/wayland/seat/mod.rs

@@ -4,6 +4,7 @@ use std::sync::Arc;
 
 use ahash::AHashMap;
 
+use sctk::reexports::client::backend::ObjectId;
 use sctk::reexports::client::protocol::wl_seat::WlSeat;
 use sctk::reexports::client::protocol::wl_touch::WlTouch;
 use sctk::reexports::client::{Connection, Proxy, QueueHandle};
@@ -13,6 +14,7 @@ use sctk::reexports::protocols::wp::text_input::zv3::client::zwp_text_input_v3::
 use sctk::seat::pointer::{ThemeSpec, ThemedPointer};
 use sctk::seat::{Capability as SeatCapability, SeatHandler, SeatState};
 
+use crate::event::WindowEvent;
 use crate::keyboard::ModifiersState;
 use crate::platform_impl::wayland::state::WinitState;
 
@@ -143,6 +145,10 @@ impl SeatHandler for WinitState {
     ) {
         let seat_state = self.seats.get_mut(&seat.id()).unwrap();
 
+        if let Some(text_input) = seat_state.text_input.take() {
+            text_input.destroy();
+        }
+
         match capability {
             SeatCapability::Touch => {
                 if let Some(touch) = seat_state.touch.take() {
@@ -174,13 +180,10 @@ impl SeatHandler for WinitState {
             }
             SeatCapability::Keyboard => {
                 seat_state.keyboard_state = None;
+                self.on_keyboard_destroy(&seat.id());
             }
             _ => (),
         }
-
-        if let Some(text_input) = seat_state.text_input.take() {
-            text_input.destroy();
-        }
     }
 
     fn new_seat(
@@ -199,6 +202,21 @@ impl SeatHandler for WinitState {
         seat: WlSeat,
     ) {
         let _ = self.seats.remove(&seat.id());
+        self.on_keyboard_destroy(&seat.id());
+    }
+}
+
+impl WinitState {
+    fn on_keyboard_destroy(&mut self, seat: &ObjectId) {
+        for (window_id, window) in self.windows.get_mut() {
+            let mut window = window.lock().unwrap();
+            let had_focus = window.has_focus();
+            window.remove_seat_focus(seat);
+            if had_focus != window.has_focus() {
+                self.events_sink
+                    .push_window_event(WindowEvent::Focused(false), *window_id);
+            }
+        }
     }
 }
 

src/platform_impl/linux/wayland/window/state.rs

@@ -4,8 +4,10 @@ use std::num::NonZeroU32;
 use std::sync::{Arc, Mutex, Weak};
 use std::time::Duration;
 
+use ahash::HashSet;
 use log::{info, warn};
 
+use sctk::reexports::client::backend::ObjectId;
 use sctk::reexports::client::protocol::wl_seat::WlSeat;
 use sctk::reexports::client::protocol::wl_shm::WlShm;
 use sctk::reexports::client::protocol::wl_surface::WlSurface;
@@ -90,8 +92,10 @@ pub struct WindowState {
     /// Whether the frame is resizable.
     resizable: bool,
 
-    /// Whether the window has focus.
-    has_focus: bool,
+    // NOTE: we can't use simple counter, since it's racy when seat getting destroyed and new
+    // is created, since add/removed stuff could be delivered a bit out of order.
+    /// Seats that has keyboard focus on that window.
+    seat_focus: HashSet<ObjectId>,
 
     /// The scale factor of the window.
     scale_factor: f64,
@@ -187,7 +191,7 @@ impl WindowState {
             fractional_scale,
             frame: None,
             frame_callback_state: FrameCallbackState::None,
-            has_focus: false,
+            seat_focus: Default::default(),
             has_pending_move: None,
             ime_allowed: false,
             ime_purpose: ImePurpose::Normal,
@@ -521,10 +525,10 @@ impl WindowState {
         }
     }
 
-    /// Whether the window is focused.
+    /// Whether the window is focused by any seat.
     #[inline]
     pub fn has_focus(&self) -> bool {
-        self.has_focus
+        !self.seat_focus.is_empty()
     }
 
     /// Whether the IME is allowed.
@@ -951,12 +955,16 @@ impl WindowState {
         }
     }
 
-    /// Mark that the window has focus.
-    ///
-    /// Should be used from routine that sends focused event.
+    /// Add seat focus for the window.
     #[inline]
-    pub fn set_has_focus(&mut self, has_focus: bool) {
-        self.has_focus = has_focus;
+    pub fn add_seat_focus(&mut self, seat: ObjectId) {
+        self.seat_focus.insert(seat);
+    }
+
+    /// Remove seat focus from the window.
+    #[inline]
+    pub fn remove_seat_focus(&mut self, seat: &ObjectId) {
+        self.seat_focus.remove(seat);
     }
 
     /// Returns `true` if the requested state was applied.