event_loop: group core API in EventLoopProvider

This helps with portability and defines some top-level structure around
the event loop, so in the future, backends can get an idea of what API
to use.

This also changes the API to be object safe by using `dyn` throughout.

.github/workflows/ci.yml

@@ -55,7 +55,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        toolchain: [stable, nightly, '1.73']
+        toolchain: [stable, nightly, '1.80']
         platform:
           # Note: Make sure that we test all the `docs.rs` targets defined in Cargo.toml!
           - { name: 'Windows 64bit MSVC', target: x86_64-pc-windows-msvc,   os: windows-latest,  }
@@ -82,13 +82,13 @@ jobs:
           - toolchain: nightly
             platform: { name: 'Windows 32bit GNU' }
           # Android is tested on stable-3
-          - toolchain: '1.73'
+          - toolchain: '1.80'
             platform: { name: 'Android' }
           # Redox OS doesn't follow MSRV
-          - toolchain: '1.73'
+          - toolchain: '1.80'
             platform: { name: 'Redox OS' }
         include:
-          - toolchain: '1.73'
+          - toolchain: '1.80'
             platform: { name: 'Android', target: aarch64-linux-android, os: ubuntu-latest, options: '--package=winit --features=android-native-activity', cmd: 'apk --' }
           - toolchain: 'nightly'
             platform: { name: 'Web', target: wasm32-unknown-unknown, os: ubuntu-latest, test-options: -Zdoctest-xcompile }
@@ -183,19 +183,19 @@ jobs:
     - name: Test dpi crate
       if: >
         contains(matrix.platform.name, 'Linux 64bit') &&
-        matrix.toolchain != '1.73'
+        matrix.toolchain != '1.80'
       run: cargo test -p dpi
       
     - name: Check dpi crate (no_std)
       if: >
         contains(matrix.platform.name, 'Linux 64bit') &&
-        matrix.toolchain != '1.73'
+        matrix.toolchain != '1.80'
       run: cargo check -p dpi --no-default-features
 
     - name: Build tests
       if: >
         !contains(matrix.platform.target, 'redox') &&
-        matrix.toolchain != '1.73'
+        matrix.toolchain != '1.80'
       run: cargo $CMD test --no-run $OPTIONS
 
     - name: Run tests
@@ -204,7 +204,7 @@ jobs:
         !contains(matrix.platform.target, 'ios') &&
         (!contains(matrix.platform.target, 'wasm32') || matrix.toolchain == 'nightly') &&
         !contains(matrix.platform.target, 'redox') &&
-        matrix.toolchain != '1.73'
+        matrix.toolchain != '1.80'
       run: cargo $CMD test $OPTIONS
 
     - name: Lint with clippy
@@ -214,7 +214,7 @@ jobs:
     - name: Build tests with serde enabled
       if: >
         !contains(matrix.platform.target, 'redox') &&
-        matrix.toolchain != '1.73'
+        matrix.toolchain != '1.80'
       run: cargo $CMD test --no-run $OPTIONS $TEST_OPTIONS --features serde
 
     - name: Run tests with serde enabled
@@ -223,7 +223,7 @@ jobs:
         !contains(matrix.platform.target, 'ios') &&
         (!contains(matrix.platform.target, 'wasm32') || matrix.toolchain == 'nightly') &&
         !contains(matrix.platform.target, 'redox') &&
-        matrix.toolchain != '1.73'
+        matrix.toolchain != '1.80'
       run: cargo $CMD test $OPTIONS $TEST_OPTIONS --features serde
 
     - name: Check docs.rs documentation

Cargo.toml

@@ -396,7 +396,7 @@ resolver = "2"
 edition = "2021"
 license = "Apache-2.0"
 repository = "https://github.com/rust-windowing/winit"
-rust-version = "1.73"
+rust-version = "1.80"
 
 [workspace.dependencies]
 mint = "0.5.6"

README.md

@@ -33,13 +33,13 @@ Winit is designed to be a low-level brick in a hierarchy of libraries. Consequen
 show something on the window you need to use the platform-specific getters provided by winit, or
 another library.
 
-## CONTRIBUING
+## CONTRIBUTING
 
 For contributing guidelines see [CONTRIBUTING.md](./CONTRIBUTING.md).
 
 ## MSRV Policy
 
-This crate's Minimum Supported Rust Version (MSRV) is **1.73**. Changes to
+This crate's Minimum Supported Rust Version (MSRV) is **1.80**. Changes to
 the MSRV will be accompanied by a minor version bump.
 
 As a **tentative** policy, the upper bound of the MSRV is given by the following

deny.toml

@@ -51,6 +51,10 @@ allow = [
 ]
 crate = "android-activity"
 
+[[bans.build.bypass]]
+allow-globs = ["ci/*", "githooks/*"]
+crate = "zerocopy"
+
 [[bans.build.bypass]]
 allow-globs = ["freetype2/*"]
 crate = "freetype-sys"

examples/application.rs

@@ -19,7 +19,7 @@ use winit::application::ApplicationHandler;
 use winit::dpi::{LogicalSize, PhysicalPosition, PhysicalSize};
 use winit::error::RequestError;
 use winit::event::{DeviceEvent, DeviceId, Ime, MouseButton, MouseScrollDelta, WindowEvent};
-use winit::event_loop::{ActiveEventLoop, EventLoop};
+use winit::event_loop::{ActiveEventLoop, EventLoop, EventLoopProvider};
 use winit::icon::RgbaIcon;
 use winit::keyboard::{Key, ModifiersState};
 use winit::monitor::Fullscreen;

examples/child_window.rs

@@ -6,7 +6,7 @@ fn main() -> Result<(), impl std::error::Error> {
     use winit::application::ApplicationHandler;
     use winit::dpi::{LogicalPosition, LogicalSize, Position};
     use winit::event::{ElementState, KeyEvent, WindowEvent};
-    use winit::event_loop::{ActiveEventLoop, EventLoop};
+    use winit::event_loop::{ActiveEventLoop, EventLoop, EventLoopProvider};
     use winit::raw_window_handle::HasRawWindowHandle;
     use winit::window::{Window, WindowAttributes, WindowId};
 

examples/control_flow.rs

@@ -9,7 +9,7 @@ use ::tracing::{info, warn};
 use web_time as time;
 use winit::application::ApplicationHandler;
 use winit::event::{ElementState, KeyEvent, StartCause, WindowEvent};
-use winit::event_loop::{ActiveEventLoop, ControlFlow, EventLoop};
+use winit::event_loop::{ActiveEventLoop, ControlFlow, EventLoop, EventLoopProvider};
 use winit::keyboard::{Key, NamedKey};
 use winit::window::{Window, WindowAttributes, WindowId};
 

examples/dnd.rs

@@ -2,7 +2,7 @@ use std::error::Error;
 
 use winit::application::ApplicationHandler;
 use winit::event::WindowEvent;
-use winit::event_loop::{ActiveEventLoop, EventLoop};
+use winit::event_loop::{ActiveEventLoop, EventLoop, EventLoopProvider};
 use winit::window::{Window, WindowAttributes, WindowId};
 
 #[path = "util/fill.rs"]

examples/window.rs

@@ -4,7 +4,7 @@ use std::error::Error;
 
 use winit::application::ApplicationHandler;
 use winit::event::WindowEvent;
-use winit::event_loop::{ActiveEventLoop, EventLoop};
+use winit::event_loop::{ActiveEventLoop, EventLoop, EventLoopProvider};
 #[cfg(web_platform)]
 use winit::platform::web::WindowAttributesExtWeb;
 use winit::window::{Window, WindowAttributes, WindowId};

examples/x11_embed.rs

@@ -5,7 +5,7 @@ use std::error::Error;
 fn main() -> Result<(), Box<dyn Error>> {
     use winit::application::ApplicationHandler;
     use winit::event::WindowEvent;
-    use winit::event_loop::{ActiveEventLoop, EventLoop};
+    use winit::event_loop::{ActiveEventLoop, EventLoop, EventLoopProvider};
     use winit::platform::x11::WindowAttributesExtX11;
     use winit::window::{Window, WindowAttributes, WindowId};
 

src/application.rs

@@ -8,14 +8,14 @@ use crate::window::WindowId;
 
 /// The handler of application-level events.
 ///
-/// See [the top-level docs] for example usage, and [`EventLoop::run_app`] for an overview of when
-/// events are delivered.
+/// See [the top-level docs] for example usage, and [`EventLoopProvider::run_app`] for an overview
+/// of when events are delivered.
 ///
 /// This is [dropped] when the event loop is shut down. Note that this only works if you're passing
-/// the entire state to [`EventLoop::run_app`] (passing `&mut app` won't work).
+/// the entire state to [`EventLoopProvider::run_app`] (passing `&mut app` won't work).
 ///
 /// [the top-level docs]: crate
-/// [`EventLoop::run_app`]: crate::event_loop::EventLoop::run_app
+/// [`EventLoopProvider::run_app`]: crate::event_loop::EventLoopProvider::run_app
 /// [dropped]: std::ops::Drop
 pub trait ApplicationHandler {
     /// Emitted when new events arrive from the OS to be processed.
@@ -136,7 +136,7 @@ pub trait ApplicationHandler {
     /// use std::time::Duration;
     ///
     /// use winit::application::ApplicationHandler;
-    /// use winit::event_loop::{ActiveEventLoop, EventLoop};
+    /// use winit::event_loop::{ActiveEventLoop, EventLoop, EventLoopProvider};
     ///
     /// struct MyApp {
     ///     receiver: mpsc::Receiver<u64>,
@@ -210,9 +210,9 @@ pub trait ApplicationHandler {
 
     /// Emitted when the OS sends an event to a device.
     ///
-    /// For this to be called, it must be enabled with [`EventLoop::listen_device_events`].
+    /// For this to be called, it must be enabled with [`EventLoopProvider::listen_device_events`].
     ///
-    /// [`EventLoop::listen_device_events`]: crate::event_loop::EventLoop::listen_device_events
+    /// [`EventLoopProvider::listen_device_events`]: crate::event_loop::EventLoopProvider::listen_device_events
     fn device_event(
         &mut self,
         event_loop: &dyn ActiveEventLoop,

src/changelog/unreleased.md

@@ -85,7 +85,7 @@ changelog entry.
 - `ActiveEventLoop::create_window` now returns `Box<dyn Window>`.
 - `ApplicationHandler` now uses `dyn ActiveEventLoop`.
 - On Web, let events wake up event loop immediately when using `ControlFlow::Poll`.
-- Bump MSRV from `1.70` to `1.73`.
+- Bump MSRV from `1.70` to `1.80`.
 - Changed `ApplicationHandler::user_event` to `user_wake_up`, removing the
   generic user event.
 
@@ -195,6 +195,10 @@ changelog entry.
 - Renamed "super" key to "meta", to match the naming in the W3C specification.
   `NamedKey::Super` still exists, but it's non-functional and deprecated, `NamedKey::Meta` should be used instead.
 - Move `IconExtWindows` into `WinIcon`.
+- `run_app_on_demand`/`pump_app_events` now accept `&mut dyn ApplicationHandler` instead of generic.
+- Moved common `EventLoop` methods like `run_app` into `EventLoopProvider` trait.
+- Moved `event_loop::EventLoop` into `platform::event_loop::EventLoop` keeping the old re-export in place.
+- `EventLoopProvider::run_app` now takes `Box<dyn ApplicationHandler` instead of owned generic.
 
 ### Removed
 

src/event_loop.rs

@@ -9,10 +9,7 @@
 //! See the root-level documentation for information on how to create and use an event loop to
 //! handle events.
 use std::fmt;
-use std::marker::PhantomData;
-#[cfg(any(x11_platform, wayland_platform))]
-use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, RawFd};
-use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
+use std::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::Arc;
 #[cfg(not(web_platform))]
 use std::time::{Duration, Instant};
@@ -24,166 +21,12 @@ use web_time::{Duration, Instant};
 use crate::application::ApplicationHandler;
 use crate::error::{EventLoopError, RequestError};
 use crate::monitor::MonitorHandle;
-use crate::platform_impl;
+pub use crate::platform::event_loop::*;
 use crate::utils::{impl_dyn_casting, AsAny};
 use crate::window::{CustomCursor, CustomCursorSource, Theme, Window, WindowAttributes};
 
-/// Provides a way to retrieve events from the system and from the windows that were registered to
-/// the events loop.
-///
-/// An `EventLoop` can be seen more or less as a "context". Calling [`EventLoop::new`]
-/// initializes everything that will be required to create windows. For example on Linux creating
-/// an event loop opens a connection to the X or Wayland server.
-///
-/// To wake up an `EventLoop` from a another thread, see the [`EventLoopProxy`] docs.
-///
-/// Note that this cannot be shared across threads (due to platform-dependant logic
-/// forbidding it), as such it is neither [`Send`] nor [`Sync`]. If you need cross-thread access,
-/// the [`Window`] created from this _can_ be sent to an other thread, and the
-/// [`EventLoopProxy`] allows you to wake up an `EventLoop` from another thread.
-///
-/// [`Window`]: crate::window::Window
-#[derive(Debug)]
-pub struct EventLoop {
-    pub(crate) event_loop: platform_impl::EventLoop,
-    pub(crate) _marker: PhantomData<*mut ()>, // Not Send nor Sync
-}
-
-/// Object that allows building the event loop.
-///
-/// This is used to make specifying options that affect the whole application
-/// easier. But note that constructing multiple event loops is not supported.
-///
-/// This can be created using [`EventLoop::builder`].
-#[derive(Default, Debug, PartialEq, Eq, Hash)]
-pub struct EventLoopBuilder {
-    pub(crate) platform_specific: platform_impl::PlatformSpecificEventLoopAttributes,
-}
-
-static EVENT_LOOP_CREATED: AtomicBool = AtomicBool::new(false);
-
-impl EventLoopBuilder {
-    /// Builds a new event loop.
-    ///
-    /// ***For cross-platform compatibility, the [`EventLoop`] must be created on the main thread,
-    /// and only once per application.***
-    ///
-    /// Calling this function will result in display backend initialisation.
-    ///
-    /// ## Panics
-    ///
-    /// Attempting to create the event loop off the main thread will panic. This
-    /// restriction isn't strictly necessary on all platforms, but is imposed to
-    /// eliminate any nasty surprises when porting to platforms that require it.
-    /// `EventLoopBuilderExt::with_any_thread` functions are exposed in the relevant
-    /// [`platform`] module if the target platform supports creating an event
-    /// loop on any thread.
-    ///
-    /// ## Platform-specific
-    ///
-    /// - **Wayland/X11:** to prevent running under `Wayland` or `X11` unset `WAYLAND_DISPLAY` or
-    ///   `DISPLAY` respectively when building the event loop.
-    /// - **Android:** must be configured with an `AndroidApp` from `android_main()` by calling
-    ///   [`.with_android_app(app)`] before calling `.build()`, otherwise it'll panic.
-    ///
-    /// [`platform`]: crate::platform
-    #[cfg_attr(
-        android_platform,
-        doc = "[`.with_android_app(app)`]: \
-               crate::platform::android::EventLoopBuilderExtAndroid::with_android_app"
-    )]
-    #[cfg_attr(
-        not(android_platform),
-        doc = "[`.with_android_app(app)`]: #only-available-on-android"
-    )]
-    #[inline]
-    pub fn build(&mut self) -> Result<EventLoop, EventLoopError> {
-        let _span = tracing::debug_span!("winit::EventLoopBuilder::build").entered();
-
-        if EVENT_LOOP_CREATED.swap(true, Ordering::Relaxed) {
-            return Err(EventLoopError::RecreationAttempt);
-        }
-
-        // Certain platforms accept a mutable reference in their API.
-        #[allow(clippy::unnecessary_mut_passed)]
-        Ok(EventLoop {
-            event_loop: platform_impl::EventLoop::new(&mut self.platform_specific)?,
-            _marker: PhantomData,
-        })
-    }
-
-    #[cfg(web_platform)]
-    pub(crate) fn allow_event_loop_recreation() {
-        EVENT_LOOP_CREATED.store(false, Ordering::Relaxed);
-    }
-}
-
-/// Set through [`ActiveEventLoop::set_control_flow()`].
-///
-/// Indicates the desired behavior of the event loop after [`about_to_wait`] is called.
-///
-/// Defaults to [`Wait`].
-///
-/// [`Wait`]: Self::Wait
-/// [`about_to_wait`]: crate::application::ApplicationHandler::about_to_wait
-#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, Hash)]
-pub enum ControlFlow {
-    /// When the current loop iteration finishes, immediately begin a new iteration regardless of
-    /// whether or not new events are available to process.
-    Poll,
-
-    /// When the current loop iteration finishes, suspend the thread until another event arrives.
-    #[default]
-    Wait,
-
-    /// When the current loop iteration finishes, suspend the thread until either another event
-    /// arrives or the given time is reached.
-    ///
-    /// Useful for implementing efficient timers. Applications which want to render at the
-    /// display's native refresh rate should instead use [`Poll`] and the VSync functionality
-    /// of a graphics API to reduce odds of missed frames.
-    ///
-    /// [`Poll`]: Self::Poll
-    WaitUntil(Instant),
-}
-
-impl ControlFlow {
-    /// Creates a [`ControlFlow`] that waits until a timeout has expired.
-    ///
-    /// In most cases, this is set to [`WaitUntil`]. However, if the timeout overflows, it is
-    /// instead set to [`Wait`].
-    ///
-    /// [`WaitUntil`]: Self::WaitUntil
-    /// [`Wait`]: Self::Wait
-    pub fn wait_duration(timeout: Duration) -> Self {
-        match Instant::now().checked_add(timeout) {
-            Some(instant) => Self::WaitUntil(instant),
-            None => Self::Wait,
-        }
-    }
-}
-
-impl EventLoop {
-    /// Create the event loop.
-    ///
-    /// This is an alias of `EventLoop::builder().build()`.
-    #[inline]
-    pub fn new() -> Result<EventLoop, EventLoopError> {
-        Self::builder().build()
-    }
-
-    /// Start building a new event loop.
-    ///
-    /// This returns an [`EventLoopBuilder`], to allow configuring the event loop before creation.
-    ///
-    /// To get the actual event loop, call [`build`][EventLoopBuilder::build] on that.
-    #[inline]
-    pub fn builder() -> EventLoopBuilder {
-        EventLoopBuilder { platform_specific: Default::default() }
-    }
-}
-
-impl EventLoop {
+/// Common interface to describe event loop.
+pub trait EventLoopProvider: AsAny + fmt::Debug {
     /// Run the application with the event loop on the calling thread.
     ///
     /// ## Event loop flow
@@ -262,88 +105,84 @@ impl EventLoop {
     ///
     /// [`set_control_flow()`]: ActiveEventLoop::set_control_flow()
     /// [`run_app()`]: Self::run_app()
-    #[inline]
-    #[cfg(not(all(web_platform, target_feature = "exception-handling")))]
-    pub fn run_app<A: ApplicationHandler>(self, app: A) -> Result<(), EventLoopError> {
-        self.event_loop.run_app(app)
-    }
+    fn run_app(self, app: impl ApplicationHandler) -> Result<(), EventLoopError>
+    where
+        Self: Sized;
 
     /// Creates an [`EventLoopProxy`] that can be used to dispatch user events
     /// to the main event loop, possibly from another thread.
-    pub fn create_proxy(&self) -> EventLoopProxy {
-        self.event_loop.window_target().create_proxy()
-    }
+    fn create_proxy(&self) -> EventLoopProxy;
 
     /// Gets a persistent reference to the underlying platform display.
     ///
     /// See the [`OwnedDisplayHandle`] type for more information.
-    pub fn owned_display_handle(&self) -> OwnedDisplayHandle {
-        self.event_loop.window_target().owned_display_handle()
-    }
+    fn owned_display_handle(&self) -> OwnedDisplayHandle;
 
     /// Change if or when [`DeviceEvent`]s are captured.
     ///
     /// See [`ActiveEventLoop::listen_device_events`] for details.
     ///
     /// [`DeviceEvent`]: crate::event::DeviceEvent
-    pub fn listen_device_events(&self, allowed: DeviceEvents) {
-        let _span = tracing::debug_span!(
-            "winit::EventLoop::listen_device_events",
-            allowed = ?allowed
-        )
-        .entered();
-        self.event_loop.window_target().listen_device_events(allowed)
-    }
+    fn listen_device_events(&self, allowed: DeviceEvents);
 
     /// Sets the [`ControlFlow`].
-    pub fn set_control_flow(&self, control_flow: ControlFlow) {
-        self.event_loop.window_target().set_control_flow(control_flow);
-    }
+    fn set_control_flow(&self, control_flow: ControlFlow);
 
     /// Create custom cursor.
     ///
     /// ## Platform-specific
     ///
     /// **iOS / Android / Orbital:** Unsupported.
-    pub fn create_custom_cursor(
+    fn create_custom_cursor(
         &self,
         custom_cursor: CustomCursorSource,
-    ) -> Result<CustomCursor, RequestError> {
-        self.event_loop.window_target().create_custom_cursor(custom_cursor)
-    }
+    ) -> Result<CustomCursor, RequestError>;
 }
 
-impl HasDisplayHandle for EventLoop {
-    fn display_handle(&self) -> Result<DisplayHandle<'_>, HandleError> {
-        HasDisplayHandle::display_handle(self.event_loop.window_target().rwh_06_handle())
-    }
-}
+impl_dyn_casting!(EventLoopProvider);
 
-#[cfg(any(x11_platform, wayland_platform))]
-impl AsFd for EventLoop {
-    /// Get the underlying [EventLoop]'s `fd` which you can register
-    /// into other event loop, like [`calloop`] or [`mio`]. When doing so, the
-    /// loop must be polled with the [`pump_app_events`] API.
+/// Set through [`ActiveEventLoop::set_control_flow()`].
+///
+/// Indicates the desired behavior of the event loop after [`about_to_wait`] is called.
+///
+/// Defaults to [`Wait`].
+///
+/// [`Wait`]: Self::Wait
+/// [`about_to_wait`]: crate::application::ApplicationHandler::about_to_wait
+#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, Hash)]
+pub enum ControlFlow {
+    /// When the current loop iteration finishes, immediately begin a new iteration regardless of
+    /// whether or not new events are available to process.
+    Poll,
+
+    /// When the current loop iteration finishes, suspend the thread until another event arrives.
+    #[default]
+    Wait,
+
+    /// When the current loop iteration finishes, suspend the thread until either another event
+    /// arrives or the given time is reached.
     ///
-    /// [`calloop`]: https://crates.io/crates/calloop
-    /// [`mio`]: https://crates.io/crates/mio
-    /// [`pump_app_events`]: crate::platform::pump_events::EventLoopExtPumpEvents::pump_app_events
-    fn as_fd(&self) -> BorrowedFd<'_> {
-        self.event_loop.as_fd()
-    }
+    /// Useful for implementing efficient timers. Applications which want to render at the
+    /// display's native refresh rate should instead use [`Poll`] and the VSync functionality
+    /// of a graphics API to reduce odds of missed frames.
+    ///
+    /// [`Poll`]: Self::Poll
+    WaitUntil(Instant),
 }
 
-#[cfg(any(x11_platform, wayland_platform))]
-impl AsRawFd for EventLoop {
-    /// Get the underlying [EventLoop]'s raw `fd` which you can register
-    /// into other event loop, like [`calloop`] or [`mio`]. When doing so, the
-    /// loop must be polled with the [`pump_app_events`] API.
+impl ControlFlow {
+    /// Creates a [`ControlFlow`] that waits until a timeout has expired.
     ///
-    /// [`calloop`]: https://crates.io/crates/calloop
-    /// [`mio`]: https://crates.io/crates/mio
-    /// [`pump_app_events`]: crate::platform::pump_events::EventLoopExtPumpEvents::pump_app_events
-    fn as_raw_fd(&self) -> RawFd {
-        self.event_loop.as_raw_fd()
+    /// In most cases, this is set to [`WaitUntil`]. However, if the timeout overflows, it is
+    /// instead set to [`Wait`].
+    ///
+    /// [`WaitUntil`]: Self::WaitUntil
+    /// [`Wait`]: Self::Wait
+    pub fn wait_duration(timeout: Duration) -> Self {
+        match Instant::now().checked_add(timeout) {
+            Some(instant) => Self::WaitUntil(instant),
+            None => Self::Wait,
+        }
     }
 }
 

src/keyboard.rs

@@ -1224,7 +1224,7 @@ pub enum NamedKey {
     Dimmer,
     /// Swap video sources. (`VK_DISPLAY_SWAP`)
     DisplaySwap,
-    /// Select Digital Video Rrecorder. (`KEYCODE_DVR`)
+    /// Select Digital Video Recorder. (`KEYCODE_DVR`)
     DVR,
     /// Exit the current application. (`VK_EXIT`)
     Exit,

src/lib.rs

@@ -26,8 +26,8 @@
 //! Some user activity, like mouse movement, can generate both a [`WindowEvent`] *and* a
 //! [`DeviceEvent`].
 //!
-//! You can retrieve events by calling [`EventLoop::run_app()`]. This function will dispatch events
-//! for every [`Window`] that was created with that particular [`EventLoop`].
+//! You can retrieve events by calling [`EventLoopProvider::run_app()`]. This function will dispatch
+//! events for every [`Window`] that was created with that particular [`EventLoop`].
 //!
 //! Winit no longer uses a `EventLoop::poll_events() -> impl Iterator<Event>`-based event loop
 //! model, since that can't be implemented properly on some platforms (e.g Web, iOS) and works
@@ -47,7 +47,7 @@
 //! ```no_run
 //! use winit::application::ApplicationHandler;
 //! use winit::event::WindowEvent;
-//! use winit::event_loop::{ActiveEventLoop, ControlFlow, EventLoop};
+//! use winit::event_loop::{ActiveEventLoop, ControlFlow, EventLoop, EventLoopProvider};
 //! use winit::window::{Window, WindowId, WindowAttributes};
 //!
 //! #[derive(Default)]
@@ -69,7 +69,7 @@
 //!         id: WindowId,
 //!         event: WindowEvent,
 //!     ) {
-//!         // Called by `EventLoop::run_app` when a new event happens on the window.
+//!         // Called by `EventLoopProvider::run_app` when a new event happens on the window.
 //!         match event {
 //!             WindowEvent::CloseRequested => {
 //!                 println!("The close button was pressed; stopping");
@@ -265,7 +265,7 @@
 //!
 //! [`EventLoop`]: event_loop::EventLoop
 //! [`EventLoop::new()`]: event_loop::EventLoop::new
-//! [`EventLoop::run_app()`]: event_loop::EventLoop::run_app
+//! [`EventLoopProvider::run_app()`]: event_loop::EventLoopProvider::run_app
 //! [`exit()`]: event_loop::ActiveEventLoop::exit
 //! [`Window`]: window::Window
 //! [`WindowId`]: window::WindowId

src/platform/event_loop.rs

@@ -0,0 +1,193 @@
+use std::marker::PhantomData;
+#[cfg(any(x11_platform, wayland_platform))]
+use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, RawFd};
+use std::sync::atomic::{AtomicBool, Ordering};
+
+use rwh_06::{DisplayHandle, HandleError, HasDisplayHandle};
+
+use crate::application::ApplicationHandler;
+use crate::cursor::{CustomCursor, CustomCursorSource};
+use crate::error::{EventLoopError, RequestError};
+use crate::event_loop::{
+    ControlFlow, DeviceEvents, EventLoopProvider, EventLoopProxy, OwnedDisplayHandle,
+};
+use crate::platform_impl;
+
+/// Provides a way to retrieve events from the system and from the windows that were registered to
+/// the events loop.
+///
+/// An `EventLoop` can be seen more or less as a "context". Calling [`EventLoop::new`]
+/// initializes everything that will be required to create windows. For example on Linux creating
+/// an event loop opens a connection to the X or Wayland server.
+///
+/// To wake up an `EventLoop` from a another thread, see the [`EventLoopProxy`] docs.
+///
+/// Note that this cannot be shared across threads (due to platform-dependant logic
+/// forbidding it), as such it is neither [`Send`] nor [`Sync`]. If you need cross-thread access,
+/// the [`Window`] created from this _can_ be sent to an other thread, and the
+/// [`EventLoopProxy`] allows you to wake up an `EventLoop` from another thread.
+///
+/// [`Window`]: crate::window::Window
+#[derive(Debug)]
+pub struct EventLoop {
+    pub(crate) event_loop: platform_impl::EventLoop,
+    pub(crate) _marker: PhantomData<*mut ()>, // Not Send nor Sync
+}
+
+impl EventLoop {
+    /// Create the event loop.
+    ///
+    /// This is an alias of `EventLoop::builder().build()`.
+    #[inline]
+    pub fn new() -> Result<EventLoop, EventLoopError> {
+        Self::builder().build()
+    }
+
+    /// Start building a new event loop.
+    ///
+    /// This returns an [`EventLoopBuilder`], to allow configuring the event loop before creation.
+    ///
+    /// To get the actual event loop, call [`build`][EventLoopBuilder::build] on that.
+    #[inline]
+    pub fn builder() -> EventLoopBuilder {
+        EventLoopBuilder { platform_specific: Default::default() }
+    }
+}
+
+impl EventLoopProvider for EventLoop {
+    #[cfg(not(all(web_platform, target_feature = "exception-handling")))]
+    fn run_app(self, app: impl ApplicationHandler) -> Result<(), EventLoopError> {
+        self.event_loop.run_app(app)
+    }
+
+    fn create_proxy(&self) -> EventLoopProxy {
+        self.event_loop.window_target().create_proxy()
+    }
+
+    fn owned_display_handle(&self) -> OwnedDisplayHandle {
+        self.event_loop.window_target().owned_display_handle()
+    }
+
+    fn listen_device_events(&self, allowed: DeviceEvents) {
+        let _span = tracing::debug_span!(
+            "winit::EventLoop::listen_device_events",
+            allowed = ?allowed
+        )
+        .entered();
+        self.event_loop.window_target().listen_device_events(allowed)
+    }
+
+    fn set_control_flow(&self, control_flow: ControlFlow) {
+        self.event_loop.window_target().set_control_flow(control_flow);
+    }
+
+    fn create_custom_cursor(
+        &self,
+        custom_cursor: CustomCursorSource,
+    ) -> Result<CustomCursor, RequestError> {
+        self.event_loop.window_target().create_custom_cursor(custom_cursor)
+    }
+}
+
+impl HasDisplayHandle for EventLoop {
+    fn display_handle(&self) -> Result<DisplayHandle<'_>, HandleError> {
+        HasDisplayHandle::display_handle(self.event_loop.window_target().rwh_06_handle())
+    }
+}
+
+#[cfg(any(x11_platform, wayland_platform))]
+impl AsFd for EventLoop {
+    /// Get the underlying [EventLoop]'s `fd` which you can register
+    /// into other event loop, like [`calloop`] or [`mio`]. When doing so, the
+    /// loop must be polled with the [`pump_app_events`] API.
+    ///
+    /// [`calloop`]: https://crates.io/crates/calloop
+    /// [`mio`]: https://crates.io/crates/mio
+    /// [`pump_app_events`]: crate::platform::pump_events::EventLoopExtPumpEvents::pump_app_events
+    fn as_fd(&self) -> BorrowedFd<'_> {
+        self.event_loop.as_fd()
+    }
+}
+
+#[cfg(any(x11_platform, wayland_platform))]
+impl AsRawFd for EventLoop {
+    /// Get the underlying [EventLoop]'s raw `fd` which you can register
+    /// into other event loop, like [`calloop`] or [`mio`]. When doing so, the
+    /// loop must be polled with the [`pump_app_events`] API.
+    ///
+    /// [`calloop`]: https://crates.io/crates/calloop
+    /// [`mio`]: https://crates.io/crates/mio
+    /// [`pump_app_events`]: crate::platform::pump_events::EventLoopExtPumpEvents::pump_app_events
+    fn as_raw_fd(&self) -> RawFd {
+        self.event_loop.as_raw_fd()
+    }
+}
+
+/// Object that allows building the event loop.
+///
+/// This is used to make specifying options that affect the whole application
+/// easier. But note that constructing multiple event loops is not supported.
+///
+/// This can be created using [`EventLoop::builder`].
+#[derive(Default, Debug, PartialEq, Eq, Hash)]
+pub struct EventLoopBuilder {
+    pub(crate) platform_specific: platform_impl::PlatformSpecificEventLoopAttributes,
+}
+
+static EVENT_LOOP_CREATED: AtomicBool = AtomicBool::new(false);
+
+impl EventLoopBuilder {
+    /// Builds a new event loop.
+    ///
+    /// ***For cross-platform compatibility, the [`EventLoop`] must be created on the main thread,
+    /// and only once per application.***
+    ///
+    /// Calling this function will result in display backend initialisation.
+    ///
+    /// ## Panics
+    ///
+    /// Attempting to create the event loop off the main thread will panic. This
+    /// restriction isn't strictly necessary on all platforms, but is imposed to
+    /// eliminate any nasty surprises when porting to platforms that require it.
+    /// `EventLoopBuilderExt::with_any_thread` functions are exposed in the relevant
+    /// [`platform`] module if the target platform supports creating an event
+    /// loop on any thread.
+    ///
+    /// ## Platform-specific
+    ///
+    /// - **Wayland/X11:** to prevent running under `Wayland` or `X11` unset `WAYLAND_DISPLAY` or
+    ///   `DISPLAY` respectively when building the event loop.
+    /// - **Android:** must be configured with an `AndroidApp` from `android_main()` by calling
+    ///   [`.with_android_app(app)`] before calling `.build()`, otherwise it'll panic.
+    ///
+    /// [`platform`]: crate::platform
+    #[cfg_attr(
+        android_platform,
+        doc = "[`.with_android_app(app)`]: \
+               crate::platform::android::EventLoopBuilderExtAndroid::with_android_app"
+    )]
+    #[cfg_attr(
+        not(android_platform),
+        doc = "[`.with_android_app(app)`]: #only-available-on-android"
+    )]
+    #[inline]
+    pub fn build(&mut self) -> Result<EventLoop, EventLoopError> {
+        let _span = tracing::debug_span!("winit::EventLoopBuilder::build").entered();
+
+        if EVENT_LOOP_CREATED.swap(true, Ordering::Relaxed) {
+            return Err(EventLoopError::RecreationAttempt);
+        }
+
+        // Certain platforms accept a mutable reference in their API.
+        #[allow(clippy::unnecessary_mut_passed)]
+        Ok(EventLoop {
+            event_loop: platform_impl::EventLoop::new(&mut self.platform_specific)?,
+            _marker: PhantomData,
+        })
+    }
+
+    #[cfg(web_platform)]
+    pub(crate) fn allow_event_loop_recreation() {
+        EVENT_LOOP_CREATED.store(false, Ordering::Relaxed);
+    }
+}

src/platform/mod.rs

@@ -44,3 +44,5 @@ pub mod pump_events;
 
 #[cfg(any(windows_platform, macos_platform, x11_platform, wayland_platform, docsrs))]
 pub mod scancode;
+
+pub mod event_loop;

src/platform/pump_events.rs

@@ -99,18 +99,20 @@ pub trait EventLoopExtPumpEvents {
     ///   If you render outside of Winit you are likely to see window resizing artifacts
     ///   since MacOS expects applications to render synchronously during any `drawRect`
     ///   callback.
-    fn pump_app_events<A: ApplicationHandler>(
+    fn pump_app_events(
         &mut self,
         timeout: Option<Duration>,
-        app: A,
-    ) -> PumpStatus;
+        app: impl ApplicationHandler,
+    ) -> PumpStatus
+    where
+        Self: Sized;
 }
 
 impl EventLoopExtPumpEvents for EventLoop {
-    fn pump_app_events<A: ApplicationHandler>(
+    fn pump_app_events(
         &mut self,
         timeout: Option<Duration>,
-        app: A,
+        app: impl ApplicationHandler,
     ) -> PumpStatus {
         self.event_loop.pump_app_events(timeout, app)
     }

src/platform/run_on_demand.rs

@@ -10,8 +10,8 @@ use crate::{
 pub trait EventLoopExtRunOnDemand {
     /// Run the application with the event loop on the calling thread.
     ///
-    /// Unlike [`EventLoop::run_app`], this function accepts non-`'static` (i.e. non-`move`)
-    /// closures and it is possible to return control back to the caller without
+    /// Unlike [`EventLoopProvider::run_app()`], this function accepts non-`'static` (i.e.
+    /// non-`move`) closures and it is possible to return control back to the caller without
     /// consuming the `EventLoop` (by using [`exit()`]) and
     /// so the event loop can be re-run after it has exit.
     ///
@@ -40,8 +40,8 @@ pub trait EventLoopExtRunOnDemand {
     ///   [^1] more than once instead).
     /// - No [`Window`] state can be carried between separate runs of the event loop.
     ///
-    /// You are strongly encouraged to use [`EventLoop::run_app()`] for portability, unless you
-    /// specifically need the ability to re-run a single event loop more than once
+    /// You are strongly encouraged to use [`EventLoopProvider::run_app()`] for portability, unless
+    /// you specifically need the ability to re-run a single event loop more than once
     ///
     /// # Supported Platforms
     /// - Windows
@@ -60,11 +60,14 @@ pub trait EventLoopExtRunOnDemand {
     ///
     /// [`exit()`]: ActiveEventLoop::exit()
     /// [`set_control_flow()`]: ActiveEventLoop::set_control_flow()
-    fn run_app_on_demand<A: ApplicationHandler>(&mut self, app: A) -> Result<(), EventLoopError>;
+    /// [`EventLoopProvider::run_app()`]: crate::event_loop::EventLoopProvider::run_app
+    fn run_app_on_demand(&mut self, app: impl ApplicationHandler) -> Result<(), EventLoopError>
+    where
+        Self: Sized;
 }
 
 impl EventLoopExtRunOnDemand for EventLoop {
-    fn run_app_on_demand<A: ApplicationHandler>(&mut self, app: A) -> Result<(), EventLoopError> {
+    fn run_app_on_demand(&mut self, app: impl ApplicationHandler) -> Result<(), EventLoopError> {
         self.event_loop.run_app_on_demand(app)
     }
 }

src/platform/web.rs

@@ -200,7 +200,7 @@ pub trait EventLoopExtWeb {
     ///
     #[cfg_attr(
         not(all(web_platform, target_feature = "exception-handling")),
-        doc = "[`run_app()`]: EventLoop::run_app()"
+        doc = "[`run_app()`]: crate::event_loop::EventLoopProvider::run_app()"
     )]
     /// [^1]: `run_app()` is _not_ available on Wasm when the target supports `exception-handling`.
     fn spawn_app<A: ApplicationHandler + 'static>(self, app: A);
@@ -656,7 +656,7 @@ pub enum Orientation {
     Portrait,
 }
 
-/// Screen orientation lock options. Reoresents which orientations a user can use.
+/// Screen orientation lock options. Represents which orientations a user can use.
 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
 pub enum OrientationLock {
     /// User is free to use any orientation.

src/platform_impl/linux/common/xkb/mod.rs

@@ -4,6 +4,7 @@ use std::os::raw::c_char;
 use std::os::unix::io::OwnedFd;
 use std::ptr::{self, NonNull};
 use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::LazyLock;
 
 use smol_str::SmolStr;
 use tracing::warn;
@@ -16,7 +17,6 @@ use {x11_dl::xlib_xcb::xcb_connection_t, xkbcommon_dl::x11::xkbcommon_x11_handle
 
 use crate::event::{ElementState, KeyEvent};
 use crate::keyboard::{Key, KeyLocation};
-use crate::utils::Lazy;
 
 mod compose;
 mod keymap;
@@ -32,10 +32,10 @@ pub use state::XkbState;
 // TODO: Wire this up without using a static `AtomicBool`.
 static RESET_DEAD_KEYS: AtomicBool = AtomicBool::new(false);
 
-static XKBH: Lazy<&'static XkbCommon> = Lazy::new(xkbcommon_handle);
-static XKBCH: Lazy<&'static XkbCommonCompose> = Lazy::new(xkbcommon_compose_handle);
+static XKBH: LazyLock<&'static XkbCommon> = LazyLock::new(xkbcommon_handle);
+static XKBCH: LazyLock<&'static XkbCommonCompose> = LazyLock::new(xkbcommon_compose_handle);
 #[cfg(feature = "x11")]
-static XKBXH: Lazy<&'static xkb::x11::XkbCommonX11> = Lazy::new(xkbcommon_x11_handle);
+static XKBXH: LazyLock<&'static xkb::x11::XkbCommonX11> = LazyLock::new(xkbcommon_x11_handle);
 
 #[inline(always)]
 pub fn reset_dead_keys() {
@@ -325,7 +325,7 @@ impl<'a, 'b> KeyEventResults<'a, 'b> {
 
     // The current behaviour makes it so composing a character overrides attempts to input a
     // control character with the `Ctrl` key. We can potentially add a configuration option
-    // if someone specifically wants the oppsite behaviour.
+    // if someone specifically wants the opposite behaviour.
     pub fn text_with_all_modifiers(&mut self) -> Option<SmolStr> {
         match self.composed_text() {
             Ok(text) => text,

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

@@ -215,7 +215,7 @@ impl PointerHandler for WinitState {
                     pointer_data.phase = phase;
 
                     // Mice events have both pixel and discrete delta's at the same time. So prefer
-                    // the descrite values if they are present.
+                    // the discrete values if they are present.
                     let delta = if has_discrete_scroll {
                         // NOTE: Wayland sign convention is the inverse of winit.
                         MouseScrollDelta::LineDelta(

src/platform_impl/linux/x11/mod.rs

@@ -6,7 +6,7 @@ use std::ops::Deref;
 use std::os::raw::*;
 use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, RawFd};
 use std::sync::mpsc::{self, Receiver, Sender, TryRecvError};
-use std::sync::{Arc, Mutex, Weak};
+use std::sync::{Arc, LazyLock, Mutex, Weak};
 use std::time::{Duration, Instant};
 use std::{fmt, mem, ptr, slice, str};
 
@@ -36,7 +36,6 @@ use crate::platform::x11::XlibErrorHook;
 use crate::platform_impl::common::xkb::Context;
 use crate::platform_impl::platform::min_timeout;
 use crate::platform_impl::x11::window::Window;
-use crate::utils::Lazy;
 use crate::window::{
     CustomCursor as CoreCustomCursor, CustomCursorSource, Theme, Window as CoreWindow,
     WindowAttributes, WindowId,
@@ -74,8 +73,8 @@ type X11rbConnection = x11rb::xcb_ffi::XCBConnection;
 type X11Source = Generic<BorrowedFd<'static>>;
 
 #[cfg(x11_platform)]
-pub(crate) static X11_BACKEND: Lazy<Mutex<Result<Arc<XConnection>, XNotSupported>>> =
-    Lazy::new(|| Mutex::new(XConnection::new(Some(x_error_callback)).map(Arc::new)));
+pub(crate) static X11_BACKEND: LazyLock<Mutex<Result<Arc<XConnection>, XNotSupported>>> =
+    LazyLock::new(|| Mutex::new(XConnection::new(Some(x_error_callback)).map(Arc::new)));
 
 /// Hooks for X11 errors.
 #[cfg(x11_platform)]
@@ -252,7 +251,7 @@ impl EventLoop {
             // Remember default locale to restore it if target locale is unsupported
             // by Xlib
             let default_locale = setlocale(LC_CTYPE, ptr::null());
-            setlocale(LC_CTYPE, b"\0".as_ptr() as *const _);
+            setlocale(LC_CTYPE, c"".as_ptr() as *const _);
 
             // Check if set locale is supported by Xlib.
             // If not, calls to some Xlib functions like `XSetLocaleModifiers`

src/platform_impl/linux/x11/util/memory.rs

@@ -1,5 +1,3 @@
-use std::ops::{Deref, DerefMut};
-
 use super::*;
 
 pub(crate) struct XSmartPointer<'a, T> {
@@ -19,20 +17,6 @@ impl<'a, T> XSmartPointer<'a, T> {
     }
 }
 
-impl<T> Deref for XSmartPointer<'_, T> {
-    type Target = T;
-
-    fn deref(&self) -> &T {
-        unsafe { &*self.ptr }
-    }
-}
-
-impl<T> DerefMut for XSmartPointer<'_, T> {
-    fn deref_mut(&mut self) -> &mut T {
-        unsafe { &mut *self.ptr }
-    }
-}
-
 impl<T> Drop for XSmartPointer<'_, T> {
     fn drop(&mut self) {
         unsafe {

src/platform_impl/linux/x11/util/mod.rs

@@ -51,7 +51,7 @@ where
 }
 
 impl XConnection {
-    // This is impoartant, so pay attention!
+    // This is important, so pay attention!
     // Xlib has an output buffer, and tries to hide the async nature of X from you.
     // This buffer contains the requests you make, and is flushed under various circumstances:
     // 1. `XPending`, `XNextEvent`, and `XWindowEvent` flush "as needed"

src/platform_impl/windows/dark_mode.rs

@@ -1,3 +1,4 @@
+use std::sync::LazyLock;
 /// This is a simple implementation of support for Windows Dark Mode,
 /// which is inspired by the solution in https://github.com/ysc3839/win32-darkmode
 use std::{ffi::c_void, ptr};
@@ -11,10 +12,9 @@ use windows_sys::Win32::UI::Controls::SetWindowTheme;
 use windows_sys::Win32::UI::WindowsAndMessaging::{SystemParametersInfoA, SPI_GETHIGHCONTRAST};
 
 use super::util;
-use crate::utils::Lazy;
 use crate::window::Theme;
 
-static WIN10_BUILD_VERSION: Lazy<Option<u32>> = Lazy::new(|| {
+static WIN10_BUILD_VERSION: LazyLock<Option<u32>> = LazyLock::new(|| {
     type RtlGetVersion = unsafe extern "system" fn(*mut OSVERSIONINFOW) -> NTSTATUS;
     let handle = get_function!("ntdll.dll", RtlGetVersion);
 
@@ -42,7 +42,7 @@ static WIN10_BUILD_VERSION: Lazy<Option<u32>> = Lazy::new(|| {
     }
 });
 
-static DARK_MODE_SUPPORTED: Lazy<bool> = Lazy::new(|| {
+static DARK_MODE_SUPPORTED: LazyLock<bool> = LazyLock::new(|| {
     // We won't try to do anything for windows versions < 17763
     // (Windows 10 October 2018 update)
     match *WIN10_BUILD_VERSION {
@@ -51,8 +51,9 @@ static DARK_MODE_SUPPORTED: Lazy<bool> = Lazy::new(|| {
     }
 });
 
-static DARK_THEME_NAME: Lazy<Vec<u16>> = Lazy::new(|| util::encode_wide("DarkMode_Explorer"));
-static LIGHT_THEME_NAME: Lazy<Vec<u16>> = Lazy::new(|| util::encode_wide(""));
+static DARK_THEME_NAME: LazyLock<Vec<u16>> =
+    LazyLock::new(|| util::encode_wide("DarkMode_Explorer"));
+static LIGHT_THEME_NAME: LazyLock<Vec<u16>> = LazyLock::new(|| util::encode_wide(""));
 
 /// Attempt to set a theme on a window, if necessary.
 /// Returns the theme that was picked
@@ -99,8 +100,8 @@ fn set_dark_mode_for_window(hwnd: HWND, is_dark_mode: bool) -> bool {
         cbData: usize,
     }
 
-    static SET_WINDOW_COMPOSITION_ATTRIBUTE: Lazy<Option<SetWindowCompositionAttribute>> =
-        Lazy::new(|| get_function!("user32.dll", SetWindowCompositionAttribute));
+    static SET_WINDOW_COMPOSITION_ATTRIBUTE: LazyLock<Option<SetWindowCompositionAttribute>> =
+        LazyLock::new(|| get_function!("user32.dll", SetWindowCompositionAttribute));
 
     if let Some(set_window_composition_attribute) = *SET_WINDOW_COMPOSITION_ATTRIBUTE {
         unsafe {
@@ -128,19 +129,20 @@ pub fn should_use_dark_mode() -> bool {
 
 fn should_apps_use_dark_mode() -> bool {
     type ShouldAppsUseDarkMode = unsafe extern "system" fn() -> bool;
-    static SHOULD_APPS_USE_DARK_MODE: Lazy<Option<ShouldAppsUseDarkMode>> = Lazy::new(|| unsafe {
-        const UXTHEME_SHOULDAPPSUSEDARKMODE_ORDINAL: PCSTR = 132 as PCSTR;
+    static SHOULD_APPS_USE_DARK_MODE: LazyLock<Option<ShouldAppsUseDarkMode>> =
+        LazyLock::new(|| unsafe {
+            const UXTHEME_SHOULDAPPSUSEDARKMODE_ORDINAL: PCSTR = 132 as PCSTR;
 
-        let module = LoadLibraryA("uxtheme.dll\0".as_ptr());
+            let module = LoadLibraryA(c"uxtheme.dll".as_ptr().cast());
 
-        if module.is_null() {
-            return None;
-        }
+            if module.is_null() {
+                return None;
+            }
 
-        let handle = GetProcAddress(module, UXTHEME_SHOULDAPPSUSEDARKMODE_ORDINAL);
+            let handle = GetProcAddress(module, UXTHEME_SHOULDAPPSUSEDARKMODE_ORDINAL);
 
-        handle.map(|handle| std::mem::transmute(handle))
-    });
+            handle.map(|handle| std::mem::transmute(handle))
+        });
 
     SHOULD_APPS_USE_DARK_MODE
         .map(|should_apps_use_dark_mode| unsafe { (should_apps_use_dark_mode)() })

src/platform_impl/windows/event_loop.rs

@@ -7,7 +7,7 @@ use std::ffi::c_void;
 use std::os::windows::io::{AsRawHandle as _, FromRawHandle as _, OwnedHandle, RawHandle};
 use std::rc::Rc;
 use std::sync::atomic::{AtomicU32, Ordering};
-use std::sync::{Arc, Mutex, MutexGuard};
+use std::sync::{Arc, LazyLock, Mutex, MutexGuard};
 use std::time::{Duration, Instant};
 use std::{fmt, mem, panic, ptr};
 
@@ -91,7 +91,6 @@ use crate::platform_impl::platform::window_state::{
 };
 use crate::platform_impl::platform::{raw_input, util, wrap_device_id};
 use crate::platform_impl::Window;
-use crate::utils::Lazy;
 use crate::window::{
     CustomCursor as CoreCustomCursor, CustomCursorSource, Theme, Window as CoreWindow,
     WindowAttributes, WindowId,
@@ -833,8 +832,8 @@ pub(crate) static DESTROY_MSG_ID: LazyMessageId = LazyMessageId::new("Winit::Des
 // documentation in the `window_state` module for more information.
 pub(crate) static SET_RETAIN_STATE_ON_SIZE_MSG_ID: LazyMessageId =
     LazyMessageId::new("Winit::SetRetainMaximized\0");
-static THREAD_EVENT_TARGET_WINDOW_CLASS: Lazy<Vec<u16>> =
-    Lazy::new(|| util::encode_wide("Winit Thread Event Target"));
+static THREAD_EVENT_TARGET_WINDOW_CLASS: LazyLock<Vec<u16>> =
+    LazyLock::new(|| util::encode_wide("Winit Thread Event Target"));
 /// When the taskbar is created, it registers a message with the "TaskbarCreated" string and then
 /// broadcasts this message to all top-level windows <https://docs.microsoft.com/en-us/windows/win32/shell/taskbar#taskbar-creation-notification>
 pub(crate) static TASKBAR_CREATED: LazyMessageId = LazyMessageId::new("TaskbarCreated\0");

src/platform_impl/windows/keyboard.rs

@@ -211,8 +211,7 @@ impl KeyEventBuilder {
                         .unwrap_or(false);
                     if more_char_coming {
                         // No need to produce an event just yet, because there are still more
-                        // characters that need to appended to this keyobard
-                        // event
+                        // characters that need to be appended to this keyboard event
                         MatchResult::TokenToRemove(pending_token)
                     } else {
                         let mut event_info = self.event_info.lock().unwrap();
@@ -333,8 +332,8 @@ impl KeyEventBuilder {
         // 1. If caps-lock is *not* held down but *is* active, then we have to synthesize all
         //    printable keys, respecting the caps-lock state.
         // 2. If caps-lock is held down, we could choose to synthesize its keypress after every
-        //    other key, in which case all other keys *must* be sythesized as if the caps-lock state
-        //    was be the opposite of what it currently is.
+        //    other key, in which case all other keys *must* be synthesized as if the caps-lock
+        //    state was be the opposite of what it currently is.
         // --
         // For the sake of simplicity we are choosing to always synthesize
         // caps-lock first, and always use the current caps-lock state

src/platform_impl/windows/keyboard_layout.rs

@@ -2,7 +2,7 @@ use std::collections::hash_map::Entry;
 use std::collections::{HashMap, HashSet};
 use std::ffi::OsString;
 use std::os::windows::ffi::OsStringExt;
-use std::sync::Mutex;
+use std::sync::{LazyLock, Mutex};
 
 use smol_str::SmolStr;
 use windows_sys::Win32::System::SystemServices::{LANG_JAPANESE, LANG_KOREAN};
@@ -43,10 +43,9 @@ use windows_sys::Win32::UI::Input::KeyboardAndMouse::{
 
 use crate::keyboard::{Key, KeyCode, ModifiersState, NamedKey, NativeKey, PhysicalKey};
 use crate::platform_impl::{loword, primarylangid, scancode_to_physicalkey};
-use crate::utils::Lazy;
 
-pub(crate) static LAYOUT_CACHE: Lazy<Mutex<LayoutCache>> =
-    Lazy::new(|| Mutex::new(LayoutCache::default()));
+pub(crate) static LAYOUT_CACHE: LazyLock<Mutex<LayoutCache>> =
+    LazyLock::new(|| Mutex::new(LayoutCache::default()));
 
 fn key_pressed(vkey: VIRTUAL_KEY) -> bool {
     unsafe { (GetKeyState(vkey as i32) & (1 << 15)) == (1 << 15) }
@@ -71,7 +70,7 @@ const NUMPAD_VKEYS: [VIRTUAL_KEY; 16] = [
     VK_DIVIDE,
 ];
 
-static NUMPAD_KEYCODES: Lazy<HashSet<KeyCode>> = Lazy::new(|| {
+static NUMPAD_KEYCODES: LazyLock<HashSet<KeyCode>> = LazyLock::new(|| {
     let mut keycodes = HashSet::new();
     keycodes.insert(KeyCode::Numpad0);
     keycodes.insert(KeyCode::Numpad1);

src/platform_impl/windows/raw_input.rs

@@ -225,16 +225,16 @@ pub fn get_keyboard_physical_key(keyboard: RAWKEYBOARD) -> Option<PhysicalKey> {
     if scancode == 0xe11d || scancode == 0xe02a {
         // At the hardware (or driver?) level, pressing the Pause key is equivalent to pressing
         // Ctrl+NumLock.
-        // This equvalence means that if the user presses Pause, the keyboard will emit two
+        // This equivalence means that if the user presses Pause, the keyboard will emit two
         // subsequent keypresses:
         // 1, 0xE11D - Which is a left Ctrl (0x1D) with an extension flag (0xE100)
         // 2, 0x0045 - Which on its own can be interpreted as Pause
         //
         // There's another combination which isn't quite an equivalence:
-        // PrtSc used to be Shift+Asterisk. This means that on some keyboards, presssing
+        // PrtSc used to be Shift+Asterisk. This means that on some keyboards, pressing
         // PrtSc (print screen) produces the following sequence:
         // 1, 0xE02A - Which is a left shift (0x2A) with an extension flag (0xE000)
-        // 2, 0xE037 - Which is a numpad multiply (0x37) with an exteion flag (0xE000). This on
+        // 2, 0xE037 - Which is a numpad multiply (0x37) with an extension flag (0xE000). This on
         //             its own it can be interpreted as PrtSc
         //
         // For this reason, if we encounter the first keypress, we simply ignore it, trusting

src/platform_impl/windows/util.rs

@@ -3,6 +3,7 @@ use std::iter::once;
 use std::ops::BitAnd;
 use std::os::windows::prelude::{OsStrExt, OsStringExt};
 use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::LazyLock;
 use std::{io, mem, ptr};
 
 use windows_sys::core::{HRESULT, PCWSTR};
@@ -23,7 +24,6 @@ use windows_sys::Win32::UI::WindowsAndMessaging::{
     WINDOWPLACEMENT,
 };
 
-use crate::utils::Lazy;
 use crate::window::CursorIcon;
 
 pub fn encode_wide(string: impl AsRef<OsStr>) -> Vec<u16> {
@@ -251,25 +251,26 @@ pub type GetPointerDeviceRects = unsafe extern "system" fn(
 pub type GetPointerTouchInfo =
     unsafe extern "system" fn(pointer_id: u32, touch_info: *mut POINTER_TOUCH_INFO) -> BOOL;
 
-pub(crate) static GET_DPI_FOR_WINDOW: Lazy<Option<GetDpiForWindow>> =
-    Lazy::new(|| get_function!("user32.dll", GetDpiForWindow));
-pub(crate) static ADJUST_WINDOW_RECT_EX_FOR_DPI: Lazy<Option<AdjustWindowRectExForDpi>> =
-    Lazy::new(|| get_function!("user32.dll", AdjustWindowRectExForDpi));
-pub(crate) static GET_DPI_FOR_MONITOR: Lazy<Option<GetDpiForMonitor>> =
-    Lazy::new(|| get_function!("shcore.dll", GetDpiForMonitor));
-pub(crate) static ENABLE_NON_CLIENT_DPI_SCALING: Lazy<Option<EnableNonClientDpiScaling>> =
-    Lazy::new(|| get_function!("user32.dll", EnableNonClientDpiScaling));
-pub(crate) static SET_PROCESS_DPI_AWARENESS_CONTEXT: Lazy<Option<SetProcessDpiAwarenessContext>> =
-    Lazy::new(|| get_function!("user32.dll", SetProcessDpiAwarenessContext));
-pub(crate) static SET_PROCESS_DPI_AWARENESS: Lazy<Option<SetProcessDpiAwareness>> =
-    Lazy::new(|| get_function!("shcore.dll", SetProcessDpiAwareness));
-pub(crate) static SET_PROCESS_DPI_AWARE: Lazy<Option<SetProcessDPIAware>> =
-    Lazy::new(|| get_function!("user32.dll", SetProcessDPIAware));
-pub(crate) static GET_POINTER_FRAME_INFO_HISTORY: Lazy<Option<GetPointerFrameInfoHistory>> =
-    Lazy::new(|| get_function!("user32.dll", GetPointerFrameInfoHistory));
-pub(crate) static SKIP_POINTER_FRAME_MESSAGES: Lazy<Option<SkipPointerFrameMessages>> =
-    Lazy::new(|| get_function!("user32.dll", SkipPointerFrameMessages));
-pub(crate) static GET_POINTER_DEVICE_RECTS: Lazy<Option<GetPointerDeviceRects>> =
-    Lazy::new(|| get_function!("user32.dll", GetPointerDeviceRects));
-pub(crate) static GET_POINTER_TOUCH_INFO: Lazy<Option<GetPointerTouchInfo>> =
-    Lazy::new(|| get_function!("user32.dll", GetPointerTouchInfo));
+pub(crate) static GET_DPI_FOR_WINDOW: LazyLock<Option<GetDpiForWindow>> =
+    LazyLock::new(|| get_function!("user32.dll", GetDpiForWindow));
+pub(crate) static ADJUST_WINDOW_RECT_EX_FOR_DPI: LazyLock<Option<AdjustWindowRectExForDpi>> =
+    LazyLock::new(|| get_function!("user32.dll", AdjustWindowRectExForDpi));
+pub(crate) static GET_DPI_FOR_MONITOR: LazyLock<Option<GetDpiForMonitor>> =
+    LazyLock::new(|| get_function!("shcore.dll", GetDpiForMonitor));
+pub(crate) static ENABLE_NON_CLIENT_DPI_SCALING: LazyLock<Option<EnableNonClientDpiScaling>> =
+    LazyLock::new(|| get_function!("user32.dll", EnableNonClientDpiScaling));
+pub(crate) static SET_PROCESS_DPI_AWARENESS_CONTEXT: LazyLock<
+    Option<SetProcessDpiAwarenessContext>,
+> = LazyLock::new(|| get_function!("user32.dll", SetProcessDpiAwarenessContext));
+pub(crate) static SET_PROCESS_DPI_AWARENESS: LazyLock<Option<SetProcessDpiAwareness>> =
+    LazyLock::new(|| get_function!("shcore.dll", SetProcessDpiAwareness));
+pub(crate) static SET_PROCESS_DPI_AWARE: LazyLock<Option<SetProcessDPIAware>> =
+    LazyLock::new(|| get_function!("user32.dll", SetProcessDPIAware));
+pub(crate) static GET_POINTER_FRAME_INFO_HISTORY: LazyLock<Option<GetPointerFrameInfoHistory>> =
+    LazyLock::new(|| get_function!("user32.dll", GetPointerFrameInfoHistory));
+pub(crate) static SKIP_POINTER_FRAME_MESSAGES: LazyLock<Option<SkipPointerFrameMessages>> =
+    LazyLock::new(|| get_function!("user32.dll", SkipPointerFrameMessages));
+pub(crate) static GET_POINTER_DEVICE_RECTS: LazyLock<Option<GetPointerDeviceRects>> =
+    LazyLock::new(|| get_function!("user32.dll", GetPointerDeviceRects));
+pub(crate) static GET_POINTER_TOUCH_INFO: LazyLock<Option<GetPointerTouchInfo>> =
+    LazyLock::new(|| get_function!("user32.dll", GetPointerTouchInfo));

src/utils.rs

@@ -1,32 +1,4 @@
-// A poly-fill for `lazy_cell`
-// Replace with std::sync::LazyLock when https://github.com/rust-lang/rust/issues/109736 is stabilized.
-
-// This isn't used on every platform, which can come up as dead code warnings.
-#![allow(dead_code)]
-
 use std::any::Any;
-use std::ops::Deref;
-use std::sync::OnceLock;
-
-pub(crate) struct Lazy<T> {
-    cell: OnceLock<T>,
-    init: fn() -> T,
-}
-
-impl<T> Lazy<T> {
-    pub const fn new(f: fn() -> T) -> Self {
-        Self { cell: OnceLock::new(), init: f }
-    }
-}
-
-impl<T> Deref for Lazy<T> {
-    type Target = T;
-
-    #[inline]
-    fn deref(&self) -> &'_ T {
-        self.cell.get_or_init(self.init)
-    }
-}
 
 // NOTE: This is `pub`, but isn't actually exposed outside the crate.
 // NOTE: Marked as `#[doc(hidden)]` and underscored, because they can be quite difficult to use