feat: implement support to enable numlock at startup

Signed-off-by: erdii <me@erdii.engineering>

niri-config/src/lib.rs

@@ -120,6 +120,8 @@ pub struct Keyboard {
     pub repeat_rate: u8,
     #[knuffel(child, unwrap(argument), default)]
     pub track_layout: TrackLayout,
+    #[knuffel(child)]
+    pub numlock: bool,
 }
 
 impl Default for Keyboard {
@@ -129,6 +131,7 @@ impl Default for Keyboard {
             repeat_delay: 600,
             repeat_rate: 25,
             track_layout: Default::default(),
+            numlock: Default::default(),
         }
     }
 }
@@ -4059,6 +4062,7 @@ mod tests {
                     repeat_delay: 600,
                     repeat_rate: 25,
                     track_layout: Window,
+                    numlock: false,
                 },
                 touchpad: Touchpad {
                     off: false,

resources/default-config.kdl

@@ -16,6 +16,9 @@ input {
             // layout "us,ru"
             // options "grp:win_space_toggle,compose:ralt,ctrl:nocaps"
         }
+
+        // Enable numlock on startup, omitting this setting disables it.
+        numlock
     }
 
     // Next sections include libinput settings.

src/niri.rs

@@ -2248,22 +2248,30 @@ impl Niri {
         let single_pixel_buffer_state = SinglePixelBufferState::new::<State>(&display_handle);
 
         let mut seat: Seat<State> = seat_state.new_wl_seat(&display_handle, backend.seat_name());
-        if let Err(err) = seat.add_keyboard(
+        let keyboard = match seat.add_keyboard(
             config_.input.keyboard.xkb.to_xkb_config(),
             config_.input.keyboard.repeat_delay.into(),
             config_.input.keyboard.repeat_rate.into(),
         ) {
-            if let smithay::input::keyboard::Error::BadKeymap = err {
-                warn!("error loading the configured xkb keymap, trying default");
-            } else {
-                warn!("error adding keyboard: {err:?}");
+            Err(err) => {
+                if let smithay::input::keyboard::Error::BadKeymap = err {
+                    warn!("error loading the configured xkb keymap, trying default");
+                } else {
+                    warn!("error adding keyboard: {err:?}");
+                }
+                seat.add_keyboard(
+                    Default::default(),
+                    config_.input.keyboard.repeat_delay.into(),
+                    config_.input.keyboard.repeat_rate.into(),
+                )
+                .unwrap()
             }
-            seat.add_keyboard(
-                Default::default(),
-                config_.input.keyboard.repeat_delay.into(),
-                config_.input.keyboard.repeat_rate.into(),
-            )
-            .unwrap();
+            Ok(keyboard) => keyboard,
+        };
+        if config_.input.keyboard.numlock {
+            let mut modifier_state = keyboard.modifier_state();
+            modifier_state.num_lock = true;
+            keyboard.set_modifier_state(modifier_state);
         }
         seat.add_pointer();