Change DeviceId to Option<DeviceId>

examples/window.rs

@@ -522,7 +522,7 @@ impl ApplicationHandler for Application {
     fn device_event(
         &mut self,
         _event_loop: &dyn ActiveEventLoop,
-        device_id: DeviceId,
+        device_id: Option<DeviceId>,
         event: DeviceEvent,
     ) {
         info!("Device {device_id:?} event: {event:?}");

src/application.rs

@@ -196,7 +196,7 @@ pub trait ApplicationHandler {
     fn device_event(
         &mut self,
         event_loop: &dyn ActiveEventLoop,
-        device_id: DeviceId,
+        device_id: Option<DeviceId>,
         event: DeviceEvent,
     ) {
         let _ = (event_loop, device_id, event);
@@ -363,7 +363,7 @@ impl<A: ?Sized + ApplicationHandler> ApplicationHandler for &mut A {
     fn device_event(
         &mut self,
         event_loop: &dyn ActiveEventLoop,
-        device_id: DeviceId,
+        device_id: Option<DeviceId>,
         event: DeviceEvent,
     ) {
         (**self).device_event(event_loop, device_id, event);
@@ -431,7 +431,7 @@ impl<A: ?Sized + ApplicationHandler> ApplicationHandler for Box<A> {
     fn device_event(
         &mut self,
         event_loop: &dyn ActiveEventLoop,
-        device_id: DeviceId,
+        device_id: Option<DeviceId>,
         event: DeviceEvent,
     ) {
         (**self).device_event(event_loop, device_id, event);

src/changelog/unreleased.md

@@ -103,6 +103,8 @@ changelog entry.
   application delegate yourself.
 - On iOS, no longer act as-if the application successfully open all URLs. Override
   `application:didFinishLaunchingWithOptions:` and provide the desired behaviour yourself.
+- Every event carrying a `DeviceId` now uses `Option<DeviceId>` instead. This signifies that the
+  device can't be uniquely differentiated.
 
 ### Removed
 

src/event.rs

@@ -78,7 +78,7 @@ pub(crate) enum Event {
     ///
     /// [`ApplicationHandler::device_event`]: crate::application::ApplicationHandler::device_event
     #[allow(clippy::enum_variant_names)]
-    DeviceEvent { device_id: DeviceId, event: DeviceEvent },
+    DeviceEvent { device_id: Option<DeviceId>, event: DeviceEvent },
 
     /// See [`ApplicationHandler::suspended`] for details.
     ///
@@ -194,7 +194,7 @@ pub enum WindowEvent {
     ///   numpad keys act as if NumLock wasn't active. When this is used, the OS sends fake key
     ///   events which are not marked as `is_synthetic`.
     KeyboardInput {
-        device_id: DeviceId,
+        device_id: Option<DeviceId>,
         event: KeyEvent,
 
         /// If `true`, the event was generated synthetically by winit
@@ -231,7 +231,7 @@ pub enum WindowEvent {
     /// [`padding`]: https://developer.mozilla.org/en-US/docs/Web/CSS/padding
     /// [`transform`]: https://developer.mozilla.org/en-US/docs/Web/CSS/transform
     CursorMoved {
-        device_id: DeviceId,
+        device_id: Option<DeviceId>,
 
         /// (x,y) coords in pixels relative to the top-left corner of the window. Because the range
         /// of this data is limited by the display area and it may have been transformed by
@@ -249,7 +249,7 @@ pub enum WindowEvent {
     /// [`border`]: https://developer.mozilla.org/en-US/docs/Web/CSS/border
     /// [`padding`]: https://developer.mozilla.org/en-US/docs/Web/CSS/padding
     /// [`transform`]: https://developer.mozilla.org/en-US/docs/Web/CSS/transform
-    CursorEntered { device_id: DeviceId },
+    CursorEntered { device_id: Option<DeviceId> },
 
     /// The cursor has left the window.
     ///
@@ -260,13 +260,13 @@ pub enum WindowEvent {
     /// [`border`]: https://developer.mozilla.org/en-US/docs/Web/CSS/border
     /// [`padding`]: https://developer.mozilla.org/en-US/docs/Web/CSS/padding
     /// [`transform`]: https://developer.mozilla.org/en-US/docs/Web/CSS/transform
-    CursorLeft { device_id: DeviceId },
+    CursorLeft { device_id: Option<DeviceId> },
 
     /// A mouse wheel movement or touchpad scroll occurred.
-    MouseWheel { device_id: DeviceId, delta: MouseScrollDelta, phase: TouchPhase },
+    MouseWheel { device_id: Option<DeviceId>, delta: MouseScrollDelta, phase: TouchPhase },
 
     /// An mouse button press has been received.
-    MouseInput { device_id: DeviceId, state: ElementState, button: MouseButton },
+    MouseInput { device_id: Option<DeviceId>, state: ElementState, button: MouseButton },
 
     /// Two-finger pinch gesture, often used for magnification.
     ///
@@ -275,7 +275,7 @@ pub enum WindowEvent {
     /// - Only available on **macOS** and **iOS**.
     /// - On iOS, not recognized by default. It must be enabled when needed.
     PinchGesture {
-        device_id: DeviceId,
+        device_id: Option<DeviceId>,
         /// Positive values indicate magnification (zooming in) and  negative
         /// values indicate shrinking (zooming out).
         ///
@@ -291,7 +291,7 @@ pub enum WindowEvent {
     /// - Only available on **iOS**.
     /// - On iOS, not recognized by default. It must be enabled when needed.
     PanGesture {
-        device_id: DeviceId,
+        device_id: Option<DeviceId>,
         /// Change in pixels of pan gesture from last update.
         delta: PhysicalPosition<f32>,
         phase: TouchPhase,
@@ -315,7 +315,7 @@ pub enum WindowEvent {
     ///
     /// - Only available on **macOS 10.8** and later, and **iOS**.
     /// - On iOS, not recognized by default. It must be enabled when needed.
-    DoubleTapGesture { device_id: DeviceId },
+    DoubleTapGesture { device_id: Option<DeviceId> },
 
     /// Two-finger rotation gesture.
     ///
@@ -327,7 +327,7 @@ pub enum WindowEvent {
     /// - Only available on **macOS** and **iOS**.
     /// - On iOS, not recognized by default. It must be enabled when needed.
     RotationGesture {
-        device_id: DeviceId,
+        device_id: Option<DeviceId>,
         /// change in rotation in degrees
         delta: f32,
         phase: TouchPhase,
@@ -338,7 +338,7 @@ pub enum WindowEvent {
     /// At the moment, only supported on Apple forcetouch-capable macbooks.
     /// The parameters are: pressure level (value between 0 and 1 representing how hard the
     /// touchpad is being pressed) and stage (integer representing the click level).
-    TouchpadPressure { device_id: DeviceId, pressure: f32, stage: i64 },
+    TouchpadPressure { device_id: Option<DeviceId>, pressure: f32, stage: i64 },
 
     /// Touch event has been received
     ///
@@ -841,7 +841,7 @@ pub enum TouchPhase {
 /// [`transform`]: https://developer.mozilla.org/en-US/docs/Web/CSS/transform
 #[derive(Debug, Clone, Copy, PartialEq)]
 pub struct Touch {
-    pub device_id: DeviceId,
+    pub device_id: Option<DeviceId>,
     pub phase: TouchPhase,
     pub location: PhysicalPosition<f64>,
     /// Describes how hard the screen was pressed. May be `None` if the platform
@@ -1023,7 +1023,6 @@ mod tests {
         ($closure:expr) => {{
             #[allow(unused_mut)]
             let mut x = $closure;
-            let did = event::DeviceId::dummy();
             let fid = event::FingerId::dummy();
 
             #[allow(deprecated)]
@@ -1053,39 +1052,39 @@ mod tests {
                 with_window_event(HoveredFile("x.txt".into()));
                 with_window_event(HoveredFileCancelled);
                 with_window_event(Ime(Enabled));
-                with_window_event(CursorMoved { device_id: did, position: (0, 0).into() });
+                with_window_event(CursorMoved { device_id: None, position: (0, 0).into() });
                 with_window_event(ModifiersChanged(event::Modifiers::default()));
-                with_window_event(CursorEntered { device_id: did });
-                with_window_event(CursorLeft { device_id: did });
+                with_window_event(CursorEntered { device_id: None });
+                with_window_event(CursorLeft { device_id: None });
                 with_window_event(MouseWheel {
-                    device_id: did,
+                    device_id: None,
                     delta: event::MouseScrollDelta::LineDelta(0.0, 0.0),
                     phase: event::TouchPhase::Started,
                 });
                 with_window_event(MouseInput {
-                    device_id: did,
+                    device_id: None,
                     state: event::ElementState::Pressed,
                     button: event::MouseButton::Other(0),
                 });
                 with_window_event(PinchGesture {
-                    device_id: did,
+                    device_id: None,
                     delta: 0.0,
                     phase: event::TouchPhase::Started,
                 });
-                with_window_event(DoubleTapGesture { device_id: did });
+                with_window_event(DoubleTapGesture { device_id: None });
                 with_window_event(RotationGesture {
-                    device_id: did,
+                    device_id: None,
                     delta: 0.0,
                     phase: event::TouchPhase::Started,
                 });
                 with_window_event(PanGesture {
-                    device_id: did,
+                    device_id: None,
                     delta: PhysicalPosition::<f32>::new(0.0, 0.0),
                     phase: event::TouchPhase::Started,
                 });
-                with_window_event(TouchpadPressure { device_id: did, pressure: 0.0, stage: 0 });
+                with_window_event(TouchpadPressure { device_id: None, pressure: 0.0, stage: 0 });
                 with_window_event(Touch(event::Touch {
-                    device_id: did,
+                    device_id: None,
                     phase: event::TouchPhase::Started,
                     location: (0.0, 0.0).into(),
                     finger_id: fid,
@@ -1100,7 +1099,7 @@ mod tests {
                 use event::DeviceEvent::*;
 
                 let with_device_event =
-                    |dev_ev| x(event::Event::DeviceEvent { device_id: did, event: dev_ev });
+                    |dev_ev| x(event::Event::DeviceEvent { device_id: None, event: dev_ev });
 
                 with_device_event(MouseMotion { delta: (0.0, 0.0).into() });
                 with_device_event(MouseWheel {
@@ -1146,20 +1145,27 @@ mod tests {
         let _ = event::StartCause::Init.clone();
 
         let did = crate::event::DeviceId::dummy().clone();
-        let fid = crate::event::FingerId::dummy().clone();
         HashSet::new().insert(did);
         let mut set = [did, did, did];
         set.sort_unstable();
         let mut set2 = BTreeSet::new();
         set2.insert(did);
         set2.insert(did);
 
+        let fid = crate::event::FingerId::dummy().clone();
+        HashSet::new().insert(fid);
+        let mut set = [fid, fid, fid];
+        set.sort_unstable();
+        let mut set2 = BTreeSet::new();
+        set2.insert(fid);
+        set2.insert(fid);
+
         HashSet::new().insert(event::TouchPhase::Started.clone());
         HashSet::new().insert(event::MouseButton::Left.clone());
         HashSet::new().insert(event::Ime::Enabled);
 
         let _ = event::Touch {
-            device_id: did,
+            device_id: None,
             phase: event::TouchPhase::Started,
             location: (0.0, 0.0).into(),
             finger_id: fid,

src/platform_impl/android/mod.rs

@@ -317,7 +317,7 @@ impl EventLoop {
         match event {
             InputEvent::MotionEvent(motion_event) => {
                 let window_id = window::WindowId(WindowId);
-                let device_id = event::DeviceId(DeviceId(motion_event.device_id()));
+                let device_id = Some(event::DeviceId(DeviceId(motion_event.device_id())));
 
                 let phase = match motion_event.action() {
                     MotionAction::Down | MotionAction::PointerDown => {
@@ -389,7 +389,7 @@ impl EventLoop {
 
                         let window_id = window::WindowId(WindowId);
                         let event = event::WindowEvent::KeyboardInput {
-                            device_id: event::DeviceId(DeviceId(key.device_id())),
+                            device_id: Some(event::DeviceId(DeviceId(key.device_id()))),
                             event: event::KeyEvent {
                                 state,
                                 physical_key: keycodes::to_physical_key(keycode),

src/platform_impl/apple/appkit/app.rs

@@ -7,7 +7,6 @@ use objc2_app_kit::{NSApplication, NSEvent, NSEventModifierFlags, NSEventType, N
 use objc2_foundation::{MainThreadMarker, NSObject};
 
 use super::app_state::AppState;
-use super::DEVICE_ID;
 use crate::event::{DeviceEvent, ElementState};
 
 declare_class!(
@@ -61,7 +60,7 @@ fn maybe_dispatch_device_event(app_state: &Rc<AppState>, event: &NSEvent) {
 
             if delta_x != 0.0 || delta_y != 0.0 {
                 app_state.maybe_queue_with_handler(move |app, event_loop| {
-                    app.device_event(event_loop, DEVICE_ID, DeviceEvent::MouseMotion {
+                    app.device_event(event_loop, None, DeviceEvent::MouseMotion {
                         delta: (delta_x, delta_y),
                     });
                 });
@@ -70,7 +69,7 @@ fn maybe_dispatch_device_event(app_state: &Rc<AppState>, event: &NSEvent) {
         NSEventType::LeftMouseDown | NSEventType::RightMouseDown | NSEventType::OtherMouseDown => {
             let button = unsafe { event.buttonNumber() } as u32;
             app_state.maybe_queue_with_handler(move |app, event_loop| {
-                app.device_event(event_loop, DEVICE_ID, DeviceEvent::Button {
+                app.device_event(event_loop, None, DeviceEvent::Button {
                     button,
                     state: ElementState::Pressed,
                 });
@@ -79,7 +78,7 @@ fn maybe_dispatch_device_event(app_state: &Rc<AppState>, event: &NSEvent) {
         NSEventType::LeftMouseUp | NSEventType::RightMouseUp | NSEventType::OtherMouseUp => {
             let button = unsafe { event.buttonNumber() } as u32;
             app_state.maybe_queue_with_handler(move |app, event_loop| {
-                app.device_event(event_loop, DEVICE_ID, DeviceEvent::Button {
+                app.device_event(event_loop, None, DeviceEvent::Button {
                     button,
                     state: ElementState::Released,
                 });

src/platform_impl/apple/appkit/mod.rs

@@ -27,7 +27,6 @@ pub(crate) use self::monitor::{MonitorHandle, VideoModeHandle};
 pub(crate) use self::window::{Window, WindowId};
 pub(crate) use self::window_delegate::PlatformSpecificWindowAttributes;
 pub(crate) use crate::cursor::OnlyCursorImageSource as PlatformCustomCursorSource;
-use crate::event::DeviceId as RootDeviceId;
 pub(crate) use crate::icon::NoIcon as PlatformIcon;
 pub(crate) use crate::platform_impl::Fullscreen;
 
@@ -41,9 +40,6 @@ impl DeviceId {
     }
 }
 
-// Constant device ID; to be removed when if backend is updated to report real device IDs.
-pub(crate) const DEVICE_ID: RootDeviceId = RootDeviceId(DeviceId);
-
 #[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct FingerId;