fix(input): require mapped layers for keyboard focus (#48)

Co-authored-by: Samuel Onoja <[email protected]>

compositor/src/handlers/layer_shell.rs

@@ -159,9 +159,12 @@ pub fn handle_commit(state: &mut Ferese, surface: &WlSurface) {
                     .layer_for_surface(&surface, WindowSurfaceType::ALL)
                     .is_some_and(|focused| focused == layer)
             });
-    if !state.session_lock.active()
+    state.reconcile_layer_keyboard_focus();
+    if pointer_on_layer
+        && !state.session_lock.active()
         && !state.input_capture.captures(1)
-        && (policy.keyboard_interactivity == KeyboardInteractivity::Exclusive || pointer_on_layer)
+        && state.layer_keyboard_eligible(&layer)
+        && state.exclusive_keyboard_layer().is_none()
         && matches!(policy.layer, Layer::Top | Layer::Overlay)
         && !layer_has_keyboard_focus(state, &layer)
     {
@@ -170,8 +173,6 @@ pub fn handle_commit(state: &mut Ferese, surface: &WlSurface) {
             Some(layer.wl_surface().clone()),
             smithay::utils::SERIAL_COUNTER.next_serial(),
         );
-    } else if !layer.can_receive_keyboard_focus() && layer_has_keyboard_focus(state, &layer) {
-        state.restore_keyboard_focus();
     }
 
     if let Err(error) = state.display_handle.flush_clients() {
@@ -179,13 +180,99 @@ pub fn handle_commit(state: &mut Ferese, surface: &WlSurface) {
     }
 }
 
+impl Ferese {
+    /// Layer-map membership tracks the role and output, not buffer mapping.
+    /// Use the renderer state updated by on_commit_buffer_handler, as for windows.
+    pub(crate) fn layer_keyboard_eligible(&self, layer: &DesktopLayerSurface) -> bool {
+        layer.layer_surface().alive()
+            && layer.can_receive_keyboard_focus()
+            && smithay::backend::renderer::utils::with_renderer_surface_state(layer.wl_surface(), |state| {
+                state.buffer().is_some()
+            })
+            .unwrap_or(false)
+            && self.space.outputs().any(|output| {
+                layer_map_for_output(output)
+                    .layers()
+                    .any(|candidate| candidate == layer)
+            })
+    }
+
+    fn keyboard_layer_root(&self) -> Option<WlSurface> {
+        let surface = self.seat.get_keyboard()?.current_focus()?;
+        let root = self
+            .popups
+            .find_popup(&surface)
+            .and_then(|popup| smithay::desktop::find_popup_root_surface(&popup).ok())
+            .unwrap_or(surface);
+        (smithay::wayland::compositor::get_role(&root) == Some(smithay::wayland::shell::wlr_layer::LAYER_SURFACE_ROLE))
+            .then_some(root)
+    }
+
+    pub(crate) fn keyboard_focused_layer(&self) -> Option<DesktopLayerSurface> {
+        self.space
+            .layer_for_surface(&self.keyboard_layer_root()?, WindowSurfaceType::ALL)
+    }
+
+    pub(crate) fn exclusive_keyboard_layer(&self) -> Option<DesktopLayerSurface> {
+        // Overlay outranks Top. Keep the current owner among peers; the protocol
+        // leaves ordering within one layer to the compositor.
+        let focused = self.keyboard_focused_layer();
+        for priority in [Layer::Overlay, Layer::Top] {
+            if let Some(layer) = focused.as_ref().filter(|layer| {
+                layer.layer() == priority
+                    && layer.cached_state().keyboard_interactivity == KeyboardInteractivity::Exclusive
+                    && self.layer_keyboard_eligible(layer)
+            }) {
+                return Some(layer.clone());
+            }
+            for output in self.space.outputs() {
+                let layers = layer_map_for_output(output)
+                    .layers_on(priority)
+                    .rev()
+                    .cloned()
+                    .collect::<Vec<_>>();
+                if let Some(layer) = layers.into_iter().find(|layer| {
+                    layer.cached_state().keyboard_interactivity == KeyboardInteractivity::Exclusive
+                        && self.layer_keyboard_eligible(layer)
+                }) {
+                    return Some(layer.clone());
+                }
+            }
+        }
+        None
+    }
+
+    pub(crate) fn reconcile_layer_keyboard_focus(&mut self) {
+        if self.session_lock.active() || self.input_capture.captures(1) {
+            return;
+        }
+        let keyboard = self.seat.get_keyboard().expect("seat has a keyboard");
+        if let Some(root) = self.keyboard_layer_root().filter(|_| {
+            !self
+                .keyboard_focused_layer()
+                .is_some_and(|layer| self.layer_keyboard_eligible(&layer))
+        }) {
+            // A popup grab cannot keep an ineligible layer alive as input owner.
+            for (popup, _) in smithay::desktop::PopupManager::popups_for_surface(&root) {
+                let _ = smithay::desktop::PopupManager::dismiss_popup(&root, &popup);
+            }
+            keyboard.unset_grab(self);
+            self.restore_keyboard_focus();
+        } else if !keyboard.is_grabbed()
+            && let Some(layer) = self.exclusive_keyboard_layer()
+            && !layer_has_keyboard_focus(self, &layer)
+        {
+            keyboard.set_focus(
+                self,
+                Some(layer.wl_surface().clone()),
+                smithay::utils::SERIAL_COUNTER.next_serial(),
+            );
+        }
+    }
+}
+
 fn layer_has_keyboard_focus(state: &Ferese, layer: &DesktopLayerSurface) -> bool {
-    state
-        .seat
-        .get_keyboard()
-        .and_then(|keyboard| keyboard.current_focus())
-        .and_then(|surface| state.space.layer_for_surface(&surface, WindowSurfaceType::ALL))
-        .is_some_and(|focused| focused == *layer)
+    state.keyboard_focused_layer().is_some_and(|focused| focused == *layer)
 }
 
 #[cfg(test)]

compositor/src/input.rs

@@ -998,9 +998,13 @@ impl Ferese {
         }
         let keyboard = self.seat.get_keyboard().expect("seat has a keyboard");
         self.focus_output_at(position);
+        if let Some(layer) = self.exclusive_keyboard_layer() {
+            keyboard.set_focus(self, Some(layer.wl_surface().clone()), serial);
+            return;
+        }
 
         if let Some((layer, _, _)) = self.layer_under(position) {
-            if layer.can_receive_keyboard_focus() {
+            if self.layer_keyboard_eligible(&layer) {
                 keyboard.set_focus(self, Some(layer.wl_surface().clone()), serial);
             } else if raise
                 && keyboard.current_focus().is_some_and(|surface| {

compositor/src/input/layer_focus_tests.rs

@@ -12,6 +12,17 @@ use std::os::unix::net::UnixStream;
 use std::sync::Arc;
 
 fn layer(state: &mut Ferese, events: &mut EventLoop<'static, Ferese>, output: &Output) -> (LayerSurface, UnixStream) {
+    layer_with_policy(state, events, output, 0, 2)
+}
+
+fn layer_with_policy(
+    state: &mut Ferese,
+    events: &mut EventLoop<'static, Ferese>,
+    output: &Output,
+    interactivity: u32,
+    level: u32,
+) -> (LayerSurface, UnixStream) {
+    let initial_focus = state.seat.get_keyboard().unwrap().current_focus();
     let (server, mut wire) = UnixStream::pair().unwrap();
     let client = state
         .display_handle
@@ -31,13 +42,19 @@ fn layer(state: &mut Ferese, events: &mut EventLoop<'static, Ferese>, output: &O
         &mut wire,
         layers.id().protocol_id(),
         0,
-        &[3, 2, 0, 2, 4, u32::from_ne_bytes(*b"bar\0")],
+        &[3, 2, 0, level, 4, u32::from_ne_bytes(*b"bar\0")],
         None,
     );
     request(&mut wire, 3, 0, &[64, 48], None);
     request(&mut wire, 3, 1, &[1 | 4], None); // Top left.
+    request(&mut wire, 3, 4, &[interactivity], None);
     request(&mut wire, 2, 6, &[], None);
     dispatch(events, state);
+    assert_eq!(
+        state.seat.get_keyboard().unwrap().current_focus(),
+        initial_focus,
+        "an initially unconfigured layer must not acquire focus"
+    );
 
     wire.set_nonblocking(true).unwrap();
     let mut bytes = Vec::new();
@@ -57,6 +74,12 @@ fn layer(state: &mut Ferese, events: &mut EventLoop<'static, Ferese>, output: &O
         offset += (header >> 16) as usize;
     }
     request(&mut wire, 3, 6, &[serial.expect("layer configure")], None);
+    dispatch(events, state);
+    assert_eq!(
+        state.seat.get_keyboard().unwrap().current_focus(),
+        initial_focus,
+        "acknowledging configure without mapping must not acquire focus"
+    );
     let mut file = tempfile::tempfile().unwrap();
     file.write_all(&0xff112233u32.to_ne_bytes().repeat(64 * 48)).unwrap();
     request(
@@ -221,3 +244,225 @@ fn on_demand_layer_focus_follows_opening_and_outside_clicks() {
         "enabling a panel away from the pointer must not steal window focus"
     );
 }
+
+fn fixture() -> (Ferese, EventLoop<'static, Ferese>, Output) {
+    let mut events = EventLoop::try_new().unwrap();
+    let mut config = crate::config::Config::default().runtime_config().unwrap();
+    config.wallpaper.path = None;
+    config.animations_enabled = false;
+    let mut state = Ferese::new(
+        &mut events,
+        smithay::reexports::wayland_server::Display::new().unwrap(),
+        config,
+    )
+    .unwrap();
+    let output = Output::new(
+        "layers".into(),
+        PhysicalProperties {
+            size: (0, 0).into(),
+            subpixel: Subpixel::Unknown,
+            make: "test".into(),
+            model: "test".into(),
+        },
+    );
+    output.change_current_state(
+        Some(Mode {
+            size: (800, 600).into(),
+            refresh: 60_000,
+        }),
+        None,
+        None,
+        None,
+    );
+    state.space.map_output(&output, (0, 0));
+    state.register_output(&output, "layers".into());
+    (state, events, output)
+}
+
+fn commit_policy(state: &mut Ferese, events: &mut EventLoop<'static, Ferese>, wire: &mut UnixStream, keyboard: u32) {
+    request(wire, 3, 4, &[keyboard], None);
+    request(wire, 2, 6, &[], None);
+    dispatch(events, state);
+}
+
+#[test]
+fn null_buffer_commit_revokes_layer_focus_without_destroying_role() {
+    if !crate::startup_tests::private_runtime(
+        "input::layer_focus_tests::null_buffer_commit_revokes_layer_focus_without_destroying_role",
+    ) {
+        return;
+    }
+    let (mut state, mut events, output) = fixture();
+    let (window, _window_wire) = window(&mut state, &mut events, 0xff112233);
+    let id = state.windows.ids()[&window];
+    assert!(state.activate_managed_window(id));
+    let fallback = Some(window.toplevel().unwrap().wl_surface().clone());
+    let keyboard = state.seat.get_keyboard().unwrap();
+    for interactivity in [1, 2] {
+        let (panel, mut wire) = layer(&mut state, &mut events, &output);
+        commit_policy(&mut state, &mut events, &mut wire, interactivity);
+        state.focus_window_at((20., 20.).into(), SERIAL_COUNTER.next_serial(), true);
+        assert_eq!(keyboard.current_focus(), Some(panel.wl_surface().clone()));
+        request(&mut wire, 2, 1, &[0, 0, 0], None); // wl_surface.attach(NULL).
+        request(&mut wire, 2, 6, &[], None);
+        dispatch(&mut events, &mut state);
+        assert!(panel.layer_surface().alive(), "the layer role survives unmapping");
+        assert!(
+            state
+                .space
+                .layer_for_surface(panel.wl_surface(), smithay::desktop::WindowSurfaceType::TOPLEVEL)
+                .is_some()
+        );
+        assert!(
+            smithay::backend::renderer::utils::with_renderer_surface_state(panel.wl_surface(), |s| s
+                .buffer()
+                .is_none())
+            .unwrap()
+        );
+        assert_eq!(
+            keyboard.current_focus(),
+            fallback,
+            "null commit must revoke keyboard focus for policy {interactivity}"
+        );
+        request(&mut wire, 2, 6, &[], None);
+        dispatch(&mut events, &mut state);
+        assert_eq!(
+            keyboard.current_focus(),
+            fallback,
+            "unmapped commits must not reclaim focus"
+        );
+        // Reconfigure with a changed size before mapping again. This follows
+        // the protocol's bufferless-commit/configure/ack sequence, including
+        // with Smithay 0.7 which retains configure state on null commits.
+        request(&mut wire, 3, 0, &[65, 48], None);
+        request(&mut wire, 2, 6, &[], None);
+        dispatch(&mut events, &mut state);
+        ack_latest_configure(&mut wire);
+        request(&mut wire, 2, 1, &[5, 0, 0], None);
+        request(&mut wire, 2, 6, &[], None);
+        dispatch(&mut events, &mut state);
+        if interactivity == 2 {
+            assert_eq!(
+                keyboard.current_focus(),
+                fallback,
+                "on-demand remap requires interaction"
+            );
+            state.focus_window_at((20., 20.).into(), SERIAL_COUNTER.next_serial(), true);
+        }
+        assert_eq!(
+            keyboard.current_focus(),
+            Some(panel.wl_surface().clone()),
+            "remapped layer remains focusable"
+        );
+        request(&mut wire, 3, 7, &[], None); // Destroy the role.
+        dispatch(&mut events, &mut state);
+        assert_eq!(keyboard.current_focus(), fallback, "destruction restores window focus");
+    }
+}
+
+fn ack_latest_configure(wire: &mut UnixStream) {
+    wire.set_nonblocking(true).unwrap();
+    let mut bytes = Vec::new();
+    assert_eq!(
+        wire.read_to_end(&mut bytes).unwrap_err().kind(),
+        std::io::ErrorKind::WouldBlock
+    );
+    wire.set_nonblocking(false).unwrap();
+    let mut serial = None;
+    let mut offset = 0;
+    while offset < bytes.len() {
+        let object = u32::from_ne_bytes(bytes[offset..offset + 4].try_into().unwrap());
+        let header = u32::from_ne_bytes(bytes[offset + 4..offset + 8].try_into().unwrap());
+        if object == 3 && header & 0xffff == 0 {
+            serial = Some(u32::from_ne_bytes(bytes[offset + 8..offset + 12].try_into().unwrap()));
+        }
+        offset += (header >> 16) as usize;
+    }
+    request(wire, 3, 6, &[serial.expect("layer configure")], None);
+}
+
+#[test]
+fn exclusive_layer_priority_and_output_removal_restore_eligible_focus() {
+    if !crate::startup_tests::private_runtime(
+        "input::layer_focus_tests::exclusive_layer_priority_and_output_removal_restore_eligible_focus",
+    ) {
+        return;
+    }
+    let (mut state, mut events, output) = fixture();
+    let (window, _window_wire) = window(&mut state, &mut events, 0xff112233);
+    assert!(state.activate_managed_window(state.windows.ids()[&window]));
+    let fallback = Some(window.toplevel().unwrap().wl_surface().clone());
+    let keyboard = state.seat.get_keyboard().unwrap();
+    let (top, mut top_wire) = layer_with_policy(&mut state, &mut events, &output, 1, 2);
+    assert_eq!(keyboard.current_focus(), Some(top.wl_surface().clone()));
+    let (overlay, mut overlay_wire) = layer_with_policy(&mut state, &mut events, &output, 1, 3);
+    assert_eq!(keyboard.current_focus(), Some(overlay.wl_surface().clone()));
+    commit_policy(&mut state, &mut events, &mut top_wire, 1);
+    assert_eq!(
+        keyboard.current_focus(),
+        Some(overlay.wl_surface().clone()),
+        "Top commits cannot steal from an exclusive Overlay"
+    );
+    request(&mut overlay_wire, 2, 1, &[0, 0, 0], None);
+    request(&mut overlay_wire, 2, 6, &[], None);
+    dispatch(&mut events, &mut state);
+    assert_eq!(
+        keyboard.current_focus(),
+        Some(top.wl_surface().clone()),
+        "unmapping falls back to another eligible exclusive layer"
+    );
+    commit_policy(&mut state, &mut events, &mut top_wire, 0);
+    assert_eq!(
+        keyboard.current_focus(),
+        fallback,
+        "disabling keyboard interaction restores the window"
+    );
+    commit_policy(&mut state, &mut events, &mut top_wire, 1);
+    assert_eq!(keyboard.current_focus(), Some(top.wl_surface().clone()));
+    state.unregister_output(&output);
+    assert_eq!(
+        keyboard.current_focus(),
+        None,
+        "removed outputs cannot retain layer focus"
+    );
+}
+
+#[test]
+fn layer_mapping_commits_do_not_override_session_lock() {
+    use smithay::reexports::wayland_protocols::ext::session_lock::v1::server::ext_session_lock_manager_v1::ExtSessionLockManagerV1;
+    if !crate::startup_tests::private_runtime(
+        "input::layer_focus_tests::layer_mapping_commits_do_not_override_session_lock",
+    ) {
+        return;
+    }
+    let (mut state, mut events, output) = fixture();
+    let (panel, mut wire) = layer_with_policy(&mut state, &mut events, &output, 1, 3);
+    let client = panel.wl_surface().client().unwrap();
+    let manager = client
+        .create_resource::<ExtSessionLockManagerV1, (), Ferese>(&state.display_handle, 1, ())
+        .unwrap();
+    request(&mut wire, manager.id().protocol_id(), 1, &[6], None);
+    dispatch(&mut events, &mut state);
+    let keyboard = state.seat.get_keyboard().unwrap();
+    assert_eq!(keyboard.current_focus(), None);
+    commit_policy(&mut state, &mut events, &mut wire, 1);
+    assert_eq!(
+        keyboard.current_focus(),
+        None,
+        "an exclusive layer cannot focus during lock acquisition"
+    );
+    request(&mut wire, 2, 1, &[0, 0, 0], None);
+    request(&mut wire, 2, 6, &[], None);
+    dispatch(&mut events, &mut state);
+    request(&mut wire, 2, 1, &[5, 0, 0], None);
+    request(&mut wire, 2, 6, &[], None);
+    dispatch(&mut events, &mut state);
+    assert_eq!(keyboard.current_focus(), None, "layer remapping cannot bypass the lock");
+    request(&mut wire, 3, 7, &[], None);
+    dispatch(&mut events, &mut state);
+    assert_eq!(
+        keyboard.current_focus(),
+        None,
+        "layer destruction preserves lock-owned focus policy"
+    );
+}

compositor/src/state/navigation.rs

@@ -713,10 +713,14 @@ impl Ferese {
             return;
         }
         let surface = self
-            .focused_window
-            .and_then(|focused| self.windows.window(focused))
-            .and_then(|window| window.toplevel())
-            .map(|toplevel| toplevel.wl_surface().clone());
+            .exclusive_keyboard_layer()
+            .map(|layer| layer.wl_surface().clone())
+            .or_else(|| {
+                self.focused_window
+                    .and_then(|focused| self.windows.window(focused))
+                    .and_then(|window| window.toplevel())
+                    .map(|toplevel| toplevel.wl_surface().clone())
+            });
 
         self.seat.get_keyboard().expect("seat has a keyboard").set_focus(
             self,

compositor/src/state/reconciliation.rs

@@ -178,6 +178,7 @@ impl Ferese {
         if changes.focus || self.session_lock.active() {
             self.restore_keyboard_focus();
         }
+        self.reconcile_layer_keyboard_focus();
         self.refresh_lock_outputs();
         self.refresh_idle_inhibition();
         let batch = self.desktop_transition.take().unwrap();