wayland: ignore events for dead objects

Nothing wrong will happen if we ignore events when compositor is at
wrong, at least crashing because compositor is just _wrong_ probably is
not a great option.

Links: alacritty/alacritty#8065

src/changelog/unreleased.md

@@ -76,3 +76,7 @@ changelog entry.
 
   This feature was incomplete, and the equivalent functionality can be trivially achieved outside
   of `winit` using `objc2-ui-kit` and calling `UIDevice::currentDevice().userInterfaceIdiom()`.
+
+### Fixed
+
+- On Wayland, avoid crashing when compositor is misbehaving.

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

@@ -18,7 +18,6 @@ use crate::keyboard::ModifiersState;
 
 use crate::platform_impl::common::xkb::Context;
 use crate::platform_impl::wayland::event_loop::sink::EventSink;
-use crate::platform_impl::wayland::seat::WinitSeatState;
 use crate::platform_impl::wayland::state::WinitState;
 use crate::platform_impl::wayland::{self, DeviceId, WindowId};
 
@@ -33,7 +32,17 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
     ) {
         let seat_state = match state.seats.get_mut(&data.seat.id()) {
             Some(seat_state) => seat_state,
-            None => return,
+            None => {
+                warn!("Received keyboard event {event:?} without seat");
+                return;
+            },
+        };
+        let keyboard_state = match seat_state.keyboard_state.as_mut() {
+            Some(keyboard_state) => keyboard_state,
+            None => {
+                warn!("Received keyboard event {event:?} without keyboard");
+                return;
+            },
         };
 
         match event {
@@ -43,7 +52,7 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                         warn!("non-xkb compatible keymap")
                     },
                     WlKeymapFormat::XkbV1 => {
-                        let context = &mut seat_state.keyboard_state.as_mut().unwrap().xkb_context;
+                        let context = &mut keyboard_state.xkb_context;
                         context.set_keymap_from_fd(fd, size as usize);
                     },
                     _ => unreachable!(),
@@ -67,7 +76,6 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                 };
 
                 // Drop the repeat, if there were any.
-                let keyboard_state = seat_state.keyboard_state.as_mut().unwrap();
                 keyboard_state.current_repeat = None;
                 if let Some(token) = keyboard_state.repeat_token.take() {
                     keyboard_state.loop_handle.remove(token);
@@ -93,7 +101,6 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
 
                 // NOTE: we should drop the repeat regardless whethere it was for the present
                 // window of for the window which just went gone.
-                let keyboard_state = seat_state.keyboard_state.as_mut().unwrap();
                 keyboard_state.current_repeat = None;
                 if let Some(token) = keyboard_state.repeat_token.take() {
                     keyboard_state.loop_handle.remove(token);
@@ -128,15 +135,14 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                 let key = key + 8;
 
                 key_input(
-                    seat_state,
+                    keyboard_state,
                     &mut state.events_sink,
                     data,
                     key,
                     ElementState::Pressed,
                     false,
                 );
 
-                let keyboard_state = seat_state.keyboard_state.as_mut().unwrap();
                 let delay = match keyboard_state.repeat_info {
                     RepeatInfo::Repeat { delay, .. } => delay,
                     RepeatInfo::Disable => return,
@@ -163,18 +169,25 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                         state.dispatched_events = true;
 
                         let data = wl_keyboard.data::<KeyboardData>().unwrap();
-                        let seat_state = state.seats.get_mut(&data.seat.id()).unwrap();
-
-                        // NOTE: The removed on event source is batched, but key change to
-                        // `None` is instant.
-                        let repeat_keycode =
-                            match seat_state.keyboard_state.as_ref().unwrap().current_repeat {
-                                Some(repeat_keycode) => repeat_keycode,
-                                None => return TimeoutAction::Drop,
-                            };
+                        let seat_state = match state.seats.get_mut(&data.seat.id()) {
+                            Some(seat_state) => seat_state,
+                            None => return TimeoutAction::Drop,
+                        };
+
+                        let keyboard_state = match seat_state.keyboard_state.as_mut() {
+                            Some(keyboard_state) => keyboard_state,
+                            None => return TimeoutAction::Drop,
+                        };
+
+                        // NOTE: The removed on event source is batched, but key change to `None`
+                        // is instant.
+                        let repeat_keycode = match keyboard_state.current_repeat {
+                            Some(repeat_keycode) => repeat_keycode,
+                            None => return TimeoutAction::Drop,
+                        };
 
                         key_input(
-                            seat_state,
+                            keyboard_state,
                             &mut state.events_sink,
                             data,
                             repeat_keycode,
@@ -183,7 +196,7 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                         );
 
                         // NOTE: the gap could change dynamically while repeat is going.
-                        match seat_state.keyboard_state.as_ref().unwrap().repeat_info {
+                        match keyboard_state.repeat_info {
                             RepeatInfo::Repeat { gap, .. } => TimeoutAction::ToDuration(gap),
                             RepeatInfo::Disable => TimeoutAction::Drop,
                         }
@@ -194,15 +207,14 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                 let key = key + 8;
 
                 key_input(
-                    seat_state,
+                    keyboard_state,
                     &mut state.events_sink,
                     data,
                     key,
                     ElementState::Released,
                     false,
                 );
 
-                let keyboard_state = seat_state.keyboard_state.as_mut().unwrap();
                 if keyboard_state.repeat_info != RepeatInfo::Disable
                     && keyboard_state.xkb_context.keymap_mut().unwrap().key_repeats(key)
                     && Some(key) == keyboard_state.current_repeat
@@ -216,7 +228,7 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
             WlKeyboardEvent::Modifiers {
                 mods_depressed, mods_latched, mods_locked, group, ..
             } => {
-                let xkb_context = &mut seat_state.keyboard_state.as_mut().unwrap().xkb_context;
+                let xkb_context = &mut keyboard_state.xkb_context;
                 let xkb_state = match xkb_context.state_mut() {
                     Some(state) => state,
                     None => return,
@@ -240,7 +252,6 @@ impl Dispatch<WlKeyboard, KeyboardData, WinitState> for WinitState {
                 );
             },
             WlKeyboardEvent::RepeatInfo { rate, delay } => {
-                let keyboard_state = seat_state.keyboard_state.as_mut().unwrap();
                 keyboard_state.repeat_info = if rate == 0 {
                     // Stop the repeat once we get a disable event.
                     keyboard_state.current_repeat = None;
@@ -348,7 +359,7 @@ impl KeyboardData {
 }
 
 fn key_input(
-    seat_state: &mut WinitSeatState,
+    keyboard_state: &mut KeyboardState,
     event_sink: &mut EventSink,
     data: &KeyboardData,
     keycode: u32,
@@ -360,8 +371,6 @@ fn key_input(
         None => return,
     };
 
-    let keyboard_state = seat_state.keyboard_state.as_mut().unwrap();
-
     let device_id = crate::event::DeviceId(crate::platform_impl::DeviceId::Wayland(DeviceId));
     if let Some(mut key_context) = keyboard_state.xkb_context.key_context() {
         let event = key_context.process_key_event(keycode, state, repeat);

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

@@ -3,6 +3,7 @@
 use std::sync::Arc;
 
 use ahash::AHashMap;
+use tracing::warn;
 
 use sctk::reexports::client::backend::ObjectId;
 use sctk::reexports::client::protocol::wl_seat::WlSeat;
@@ -76,7 +77,13 @@ impl SeatHandler for WinitState {
         seat: WlSeat,
         capability: SeatCapability,
     ) {
-        let seat_state = self.seats.get_mut(&seat.id()).unwrap();
+        let seat_state = match self.seats.get_mut(&seat.id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received wl_seat::new_capability for unknown seat");
+                return;
+            },
+        };
 
         match capability {
             SeatCapability::Touch if seat_state.touch.is_none() => {
@@ -139,7 +146,13 @@ impl SeatHandler for WinitState {
         seat: WlSeat,
         capability: SeatCapability,
     ) {
-        let seat_state = self.seats.get_mut(&seat.id()).unwrap();
+        let seat_state = match self.seats.get_mut(&seat.id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received wl_seat::remove_capability for unknown seat");
+                return;
+            },
+        };
 
         if let Some(text_input) = seat_state.text_input.take() {
             text_input.destroy();

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

@@ -4,6 +4,8 @@ use std::ops::Deref;
 use std::sync::{Arc, Mutex};
 use std::time::Duration;
 
+use tracing::warn;
+
 use sctk::reexports::client::delegate_dispatch;
 use sctk::reexports::client::protocol::wl_pointer::WlPointer;
 use sctk::reexports::client::protocol::wl_seat::WlSeat;
@@ -41,7 +43,21 @@ impl PointerHandler for WinitState {
         events: &[PointerEvent],
     ) {
         let seat = pointer.winit_data().seat();
-        let seat_state = self.seats.get(&seat.id()).unwrap();
+        let seat_state = match self.seats.get(&seat.id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received pointer event without seat");
+                return;
+            },
+        };
+
+        let themed_pointer = match seat_state.pointer.as_ref() {
+            Some(pointer) => pointer,
+            None => {
+                warn!("Received pointer event without pointer");
+                return;
+            },
+        };
 
         let device_id = crate::event::DeviceId(crate::platform_impl::DeviceId::Wayland(DeviceId));
 
@@ -78,9 +94,7 @@ impl PointerHandler for WinitState {
                         event.position.0,
                         event.position.1,
                     ) {
-                        if let Some(pointer) = seat_state.pointer.as_ref() {
-                            let _ = pointer.set_cursor(connection, icon);
-                        }
+                        let _ = themed_pointer.set_cursor(connection, icon);
                     }
                 },
                 PointerEventKind::Leave { .. } if parent_surface != surface => {
@@ -113,9 +127,7 @@ impl PointerHandler for WinitState {
                     self.events_sink
                         .push_window_event(WindowEvent::CursorEntered { device_id }, window_id);
 
-                    if let Some(pointer) = seat_state.pointer.as_ref().map(Arc::downgrade) {
-                        window.pointer_entered(pointer);
-                    }
+                    window.pointer_entered(Arc::downgrade(themed_pointer));
 
                     // Set the currently focused surface.
                     pointer.winit_data().inner.lock().unwrap().surface = Some(window_id);
@@ -126,9 +138,7 @@ impl PointerHandler for WinitState {
                     );
                 },
                 PointerEventKind::Leave { .. } => {
-                    if let Some(pointer) = seat_state.pointer.as_ref().map(Arc::downgrade) {
-                        window.pointer_left(pointer);
-                    }
+                    window.pointer_left(Arc::downgrade(themed_pointer));
 
                     // Remove the active surface.
                     pointer.winit_data().inner.lock().unwrap().surface = None;
@@ -185,13 +195,13 @@ impl PointerHandler for WinitState {
                     // Mice events have both pixel and discrete delta's at the same time. So prefer
                     // the descrite values if they are present.
                     let delta = if has_discrete_scroll {
-                        // XXX Wayland sign convention is the inverse of winit.
+                        // NOTE: Wayland sign convention is the inverse of winit.
                         MouseScrollDelta::LineDelta(
                             (-horizontal.discrete) as f32,
                             (-vertical.discrete) as f32,
                         )
                     } else {
-                        // XXX Wayland sign convention is the inverse of winit.
+                        // NOTE: Wayland sign convention is the inverse of winit.
                         MouseScrollDelta::PixelDelta(
                             LogicalPosition::new(-horizontal.absolute, -vertical.absolute)
                                 .to_physical(scale_factor),

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

@@ -1,5 +1,7 @@
 //! Touch handling.
 
+use tracing::warn;
+
 use sctk::reexports::client::protocol::wl_seat::WlSeat;
 use sctk::reexports::client::protocol::wl_surface::WlSurface;
 use sctk::reexports::client::protocol::wl_touch::WlTouch;
@@ -31,11 +33,16 @@ impl TouchHandler for WinitState {
             None => return,
         };
 
-        let location = LogicalPosition::<f64>::from(position);
-
-        let seat_state = self.seats.get_mut(&touch.seat().id()).unwrap();
+        let seat_state = match self.seats.get_mut(&touch.seat().id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received wl_touch::down without seat");
+                return;
+            },
+        };
 
         // Update the state of the point.
+        let location = LogicalPosition::<f64>::from(position);
         seat_state.touch_map.insert(id, TouchPoint { surface, location });
 
         self.events_sink.push_window_event(
@@ -61,7 +68,13 @@ impl TouchHandler for WinitState {
         _: u32,
         id: i32,
     ) {
-        let seat_state = self.seats.get_mut(&touch.seat().id()).unwrap();
+        let seat_state = match self.seats.get_mut(&touch.seat().id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received wl_touch::up without seat");
+                return;
+            },
+        };
 
         // Remove the touch point.
         let touch_point = match seat_state.touch_map.remove(&id) {
@@ -98,7 +111,13 @@ impl TouchHandler for WinitState {
         id: i32,
         position: (f64, f64),
     ) {
-        let seat_state = self.seats.get_mut(&touch.seat().id()).unwrap();
+        let seat_state = match self.seats.get_mut(&touch.seat().id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received wl_touch::motion without seat");
+                return;
+            },
+        };
 
         // Remove the touch point.
         let touch_point = match seat_state.touch_map.get_mut(&id) {
@@ -129,7 +148,13 @@ impl TouchHandler for WinitState {
     }
 
     fn cancel(&mut self, _: &Connection, _: &QueueHandle<Self>, touch: &WlTouch) {
-        let seat_state = self.seats.get_mut(&touch.seat().id()).unwrap();
+        let seat_state = match self.seats.get_mut(&touch.seat().id()) {
+            Some(seat_state) => seat_state,
+            None => {
+                warn!("Received wl_touch::cancel without seat");
+                return;
+            },
+        };
 
         for (id, touch_point) in seat_state.touch_map.drain() {
             let window_id = wayland::make_wid(&touch_point.surface);