Remove lifetime from the Event

Lifetimes don't work nicely when dealing with multithreaded environments
in the current design of the existing winit's event handling model, so
remove it in favor of `Weak` fences passed to client, so they could
try to update the size.

Fixes rust-windowing#1387.

Author: kchibisov

CHANGELOG.md

@@ -8,6 +8,8 @@ And please only add new entries to the top of this list, right below the `# Unre
 
 # Unreleased
 
+- **Breaking:** Remove `PartialEq` implementation from the event.
+- **Breaking:** Remove `lifetime` from the event.
 - **Breaking:** `ActivationTokenDone` event which could be requested with the new `startup_notify` module, see its docs for more.
 - On Wayland, make double clicking and moving the CSD frame more reliable.
 - On macOS, add tabbing APIs on `WindowExtMacOS` and `EventLoopWindowTargetExtMacOS`.

examples/child_window.rs

@@ -46,7 +46,7 @@ fn main() -> Result<(), impl std::error::Error> {
 
     println!("parent window: {parent_window:?})");
 
-    event_loop.run(move |event: Event<'_, ()>, event_loop, control_flow| {
+    event_loop.run(move |event: Event<()>, event_loop, control_flow| {
         *control_flow = ControlFlow::Wait;
 
         if let Event::WindowEvent { event, window_id } = event {

examples/multithreaded.rs

@@ -195,9 +195,7 @@ fn main() -> Result<(), impl std::error::Error> {
                 }
                 _ => {
                     if let Some(tx) = window_senders.get(&window_id) {
-                        if let Some(event) = event.to_static() {
-                            tx.send(event).unwrap();
-                        }
+                        tx.send(event).unwrap();
                     }
                 }
             },

src/event.rs

@@ -34,10 +34,12 @@
 //!
 //! [`EventLoop::run(...)`]: crate::event_loop::EventLoop::run
 //! [`ControlFlow::WaitUntil`]: crate::event_loop::ControlFlow::WaitUntil
-use smol_str::SmolStr;
 use std::path::PathBuf;
+use std::sync::{Mutex, Weak};
 #[cfg(not(wasm_platform))]
 use std::time::Instant;
+
+use smol_str::SmolStr;
 #[cfg(wasm_platform)]
 use web_time::Instant;
 
@@ -54,8 +56,8 @@ use crate::{
 /// Describes a generic event.
 ///
 /// See the module-level docs for more information on the event loop manages each event.
-#[derive(Debug, PartialEq)]
-pub enum Event<'a, T: 'static> {
+#[derive(Debug)]
+pub enum Event<T: 'static> {
     /// Emitted when new events arrive from the OS to be processed.
     ///
     /// This event type is useful as a place to put code that should be done before you start
@@ -67,7 +69,7 @@ pub enum Event<'a, T: 'static> {
     /// Emitted when the OS sends an event to a winit window.
     WindowEvent {
         window_id: WindowId,
-        event: WindowEvent<'a>,
+        event: WindowEvent,
     },
 
     /// Emitted when the OS sends an event to a device.
@@ -261,33 +263,9 @@ pub enum Event<'a, T: 'static> {
     LoopDestroyed,
 }
 
-impl<T: Clone> Clone for Event<'static, T> {
-    fn clone(&self) -> Self {
-        use self::Event::*;
-        match self {
-            WindowEvent { window_id, event } => WindowEvent {
-                window_id: *window_id,
-                event: event.clone(),
-            },
-            UserEvent(event) => UserEvent(event.clone()),
-            DeviceEvent { device_id, event } => DeviceEvent {
-                device_id: *device_id,
-                event: event.clone(),
-            },
-            NewEvents(cause) => NewEvents(*cause),
-            MainEventsCleared => MainEventsCleared,
-            RedrawRequested(wid) => RedrawRequested(*wid),
-            RedrawEventsCleared => RedrawEventsCleared,
-            LoopDestroyed => LoopDestroyed,
-            Suspended => Suspended,
-            Resumed => Resumed,
-        }
-    }
-}
-
-impl<'a, T> Event<'a, T> {
+impl<T> Event<T> {
     #[allow(clippy::result_large_err)]
-    pub fn map_nonuser_event<U>(self) -> Result<Event<'a, U>, Event<'a, T>> {
+    pub fn map_nonuser_event<U>(self) -> Result<Event<U>, Event<T>> {
         use self::Event::*;
         match self {
             UserEvent(_) => Err(self),
@@ -302,26 +280,6 @@ impl<'a, T> Event<'a, T> {
             Resumed => Ok(Resumed),
         }
     }
-
-    /// If the event doesn't contain a reference, turn it into an event with a `'static` lifetime.
-    /// Otherwise, return `None`.
-    pub fn to_static(self) -> Option<Event<'static, T>> {
-        use self::Event::*;
-        match self {
-            WindowEvent { window_id, event } => event
-                .to_static()
-                .map(|event| WindowEvent { window_id, event }),
-            UserEvent(event) => Some(UserEvent(event)),
-            DeviceEvent { device_id, event } => Some(DeviceEvent { device_id, event }),
-            NewEvents(cause) => Some(NewEvents(cause)),
-            MainEventsCleared => Some(MainEventsCleared),
-            RedrawRequested(wid) => Some(RedrawRequested(wid)),
-            RedrawEventsCleared => Some(RedrawEventsCleared),
-            LoopDestroyed => Some(LoopDestroyed),
-            Suspended => Some(Suspended),
-            Resumed => Some(Resumed),
-        }
-    }
 }
 
 /// Describes the reason the event loop is resuming.
@@ -355,8 +313,8 @@ pub enum StartCause {
 }
 
 /// Describes an event from a [`Window`].
-#[derive(Debug, PartialEq)]
-pub enum WindowEvent<'a> {
+#[derive(Debug, Clone)]
+pub enum WindowEvent {
     /// The activation token was delivered back and now could be used.
     ///
     #[cfg_attr(
@@ -590,7 +548,9 @@ pub enum WindowEvent<'a> {
     /// For more information about DPI in general, see the [`dpi`](crate::dpi) module.
     ScaleFactorChanged {
         scale_factor: f64,
-        new_inner_size: &'a mut PhysicalSize<u32>,
+        /// The pointer could be upgraded successfully only from the callback for this event,
+        /// otherwise it'll always fail to do so.
+        new_inner_size: Weak<Mutex<PhysicalSize<u32>>>,
     },
 
     /// The system window theme has changed.
@@ -619,209 +579,6 @@ pub enum WindowEvent<'a> {
     Occluded(bool),
 }
 
-impl Clone for WindowEvent<'static> {
-    fn clone(&self) -> Self {
-        use self::WindowEvent::*;
-        return match self {
-            ActivationTokenDone { serial, token } => ActivationTokenDone {
-                serial: *serial,
-                token: token.clone(),
-            },
-            Resized(size) => Resized(*size),
-            Moved(pos) => Moved(*pos),
-            CloseRequested => CloseRequested,
-            Destroyed => Destroyed,
-            DroppedFile(file) => DroppedFile(file.clone()),
-            HoveredFile(file) => HoveredFile(file.clone()),
-            HoveredFileCancelled => HoveredFileCancelled,
-            Focused(f) => Focused(*f),
-            KeyboardInput {
-                device_id,
-                event,
-                is_synthetic,
-            } => KeyboardInput {
-                device_id: *device_id,
-                event: event.clone(),
-                is_synthetic: *is_synthetic,
-            },
-            Ime(preedit_state) => Ime(preedit_state.clone()),
-            ModifiersChanged(modifiers) => ModifiersChanged(*modifiers),
-            CursorMoved {
-                device_id,
-                position,
-            } => CursorMoved {
-                device_id: *device_id,
-                position: *position,
-            },
-            CursorEntered { device_id } => CursorEntered {
-                device_id: *device_id,
-            },
-            CursorLeft { device_id } => CursorLeft {
-                device_id: *device_id,
-            },
-            MouseWheel {
-                device_id,
-                delta,
-                phase,
-            } => MouseWheel {
-                device_id: *device_id,
-                delta: *delta,
-                phase: *phase,
-            },
-            MouseInput {
-                device_id,
-                state,
-                button,
-            } => MouseInput {
-                device_id: *device_id,
-                state: *state,
-                button: *button,
-            },
-            TouchpadMagnify {
-                device_id,
-                delta,
-                phase,
-            } => TouchpadMagnify {
-                device_id: *device_id,
-                delta: *delta,
-                phase: *phase,
-            },
-            SmartMagnify { device_id } => SmartMagnify {
-                device_id: *device_id,
-            },
-            TouchpadRotate {
-                device_id,
-                delta,
-                phase,
-            } => TouchpadRotate {
-                device_id: *device_id,
-                delta: *delta,
-                phase: *phase,
-            },
-            TouchpadPressure {
-                device_id,
-                pressure,
-                stage,
-            } => TouchpadPressure {
-                device_id: *device_id,
-                pressure: *pressure,
-                stage: *stage,
-            },
-            AxisMotion {
-                device_id,
-                axis,
-                value,
-            } => AxisMotion {
-                device_id: *device_id,
-                axis: *axis,
-                value: *value,
-            },
-            Touch(touch) => Touch(*touch),
-            ThemeChanged(theme) => ThemeChanged(*theme),
-            ScaleFactorChanged { .. } => {
-                unreachable!("Static event can't be about scale factor changing")
-            }
-            Occluded(occluded) => Occluded(*occluded),
-        };
-    }
-}
-
-impl<'a> WindowEvent<'a> {
-    pub fn to_static(self) -> Option<WindowEvent<'static>> {
-        use self::WindowEvent::*;
-        match self {
-            ActivationTokenDone { serial, token } => Some(ActivationTokenDone { serial, token }),
-            Resized(size) => Some(Resized(size)),
-            Moved(position) => Some(Moved(position)),
-            CloseRequested => Some(CloseRequested),
-            Destroyed => Some(Destroyed),
-            DroppedFile(file) => Some(DroppedFile(file)),
-            HoveredFile(file) => Some(HoveredFile(file)),
-            HoveredFileCancelled => Some(HoveredFileCancelled),
-            Focused(focused) => Some(Focused(focused)),
-            KeyboardInput {
-                device_id,
-                event,
-                is_synthetic,
-            } => Some(KeyboardInput {
-                device_id,
-                event,
-                is_synthetic,
-            }),
-            ModifiersChanged(modifers) => Some(ModifiersChanged(modifers)),
-            Ime(event) => Some(Ime(event)),
-            CursorMoved {
-                device_id,
-                position,
-            } => Some(CursorMoved {
-                device_id,
-                position,
-            }),
-            CursorEntered { device_id } => Some(CursorEntered { device_id }),
-            CursorLeft { device_id } => Some(CursorLeft { device_id }),
-            MouseWheel {
-                device_id,
-                delta,
-                phase,
-            } => Some(MouseWheel {
-                device_id,
-                delta,
-                phase,
-            }),
-            MouseInput {
-                device_id,
-                state,
-                button,
-            } => Some(MouseInput {
-                device_id,
-                state,
-                button,
-            }),
-            TouchpadMagnify {
-                device_id,
-                delta,
-                phase,
-            } => Some(TouchpadMagnify {
-                device_id,
-                delta,
-                phase,
-            }),
-            SmartMagnify { device_id } => Some(SmartMagnify { device_id }),
-            TouchpadRotate {
-                device_id,
-                delta,
-                phase,
-            } => Some(TouchpadRotate {
-                device_id,
-                delta,
-                phase,
-            }),
-            TouchpadPressure {
-                device_id,
-                pressure,
-                stage,
-            } => Some(TouchpadPressure {
-                device_id,
-                pressure,
-                stage,
-            }),
-            AxisMotion {
-                device_id,
-                axis,
-                value,
-            } => Some(AxisMotion {
-                device_id,
-                axis,
-                value,
-            }),
-            Touch(touch) => Some(Touch(touch)),
-            ThemeChanged(theme) => Some(ThemeChanged(theme)),
-            ScaleFactorChanged { .. } => None,
-            Occluded(occluded) => Some(Occluded(occluded)),
-        }
-    }
-}
-
 /// Identifier of an input device.
 ///
 /// Whenever you receive an event arising from a particular input device, this event contains a `DeviceId` which

src/event_loop.rs

@@ -314,7 +314,7 @@ impl<T> EventLoop<T> {
     #[inline]
     pub fn run<F>(self, event_handler: F) -> Result<(), RunLoopError>
     where
-        F: 'static + FnMut(Event<'_, T>, &EventLoopWindowTarget<T>, &mut ControlFlow),
+        F: 'static + FnMut(Event<T>, &EventLoopWindowTarget<T>, &mut ControlFlow),
     {
         self.event_loop.run(event_handler)
     }

src/platform/pump_events.rs

@@ -174,23 +174,15 @@ pub trait EventLoopExtPumpEvents {
     ///   callback.
     fn pump_events<F>(&mut self, timeout: Option<Duration>, event_handler: F) -> PumpStatus
     where
-        F: FnMut(
-            Event<'_, Self::UserEvent>,
-            &EventLoopWindowTarget<Self::UserEvent>,
-            &mut ControlFlow,
-        );
+        F: FnMut(Event<Self::UserEvent>, &EventLoopWindowTarget<Self::UserEvent>, &mut ControlFlow);
 }
 
 impl<T> EventLoopExtPumpEvents for EventLoop<T> {
     type UserEvent = T;
 
     fn pump_events<F>(&mut self, timeout: Option<Duration>, event_handler: F) -> PumpStatus
     where
-        F: FnMut(
-            Event<'_, Self::UserEvent>,
-            &EventLoopWindowTarget<Self::UserEvent>,
-            &mut ControlFlow,
-        ),
+        F: FnMut(Event<Self::UserEvent>, &EventLoopWindowTarget<Self::UserEvent>, &mut ControlFlow),
     {
         self.event_loop.pump_events(timeout, event_handler)
     }