From bd053c1bf0a68df4d390f982c04882626c0572c7 Mon Sep 17 00:00:00 2001
From: marc2332 <mespinsanz@gmail.com>
Date: Fri, 31 May 2024 16:53:40 -0400
Subject: [PATCH] feat: add sealed `trait GlutinEventLoop` to abstract over
 `{,Active}EventLoop` in `winit` 0.30.0

Co-Authored-By: Erich Gubler <erichdongubler@gmail.com>
---
 glutin-winit/CHANGELOG.md      |  1 +
 glutin-winit/src/event_loop.rs | 51 ++++++++++++++++++++++++++++++++++
 glutin-winit/src/lib.rs        | 20 +++++++++----
 3 files changed, 66 insertions(+), 6 deletions(-)
 create mode 100644 glutin-winit/src/event_loop.rs

diff --git a/glutin-winit/CHANGELOG.md b/glutin-winit/CHANGELOG.md
index 769c567e2c..5f943fce73 100644
--- a/glutin-winit/CHANGELOG.md
+++ b/glutin-winit/CHANGELOG.md
@@ -1,6 +1,7 @@
 # Unreleased
 
 - **Breaking:** Update _winit_ to `0.30`. See [winit's CHANGELOG](https://github.com/rust-windowing/winit/releases/tag/v0.30.0) for more info.
+- Add the `GlutinEventLoop` trait to maintain compatibility with the now deprecated `EventLoop` but also support the new `ActiveEventLoop`.
 - Update `DisplayBuilder` to use `WindowAttributes` instead of `WindowBuilder`.
 
 # Version 0.4.2
diff --git a/glutin-winit/src/event_loop.rs b/glutin-winit/src/event_loop.rs
new file mode 100644
index 0000000000..13c157a49b
--- /dev/null
+++ b/glutin-winit/src/event_loop.rs
@@ -0,0 +1,51 @@
+use raw_window_handle::{DisplayHandle, HandleError, HasDisplayHandle};
+use winit::error::OsError;
+use winit::event_loop::{ActiveEventLoop, EventLoop};
+use winit::window::{Window, WindowAttributes};
+
+use crate::private::Sealed;
+
+/// [`ActiveEventLoop`] is the recommended way to interact with the event
+/// loop, but for compatibility purposes [`EventLoop`] is also supported
+/// although not recommended anymore as it has been deprecated by Winit.
+pub trait GlutinEventLoop: Sealed {
+    /// Create the window.
+    ///
+    /// Possible causes of error include denied permission, incompatible system,
+    /// and lack of memory.
+    ///
+    /// ## Platform-specific
+    ///
+    /// - **Web:** The window is created but not inserted into the web page
+    ///   automatically. Please see the web platform module for more
+    ///   information.
+    fn create_window(&self, window_attributes: WindowAttributes) -> Result<Window, OsError>;
+
+    /// Get a handle to the display controller of the windowing system.
+    fn glutin_display_handle(&self) -> Result<DisplayHandle<'_>, HandleError>;
+}
+
+impl Sealed for ActiveEventLoop {}
+
+impl GlutinEventLoop for ActiveEventLoop {
+    fn create_window(&self, window_attributes: WindowAttributes) -> Result<Window, OsError> {
+        self.create_window(window_attributes)
+    }
+
+    fn glutin_display_handle(&self) -> Result<DisplayHandle<'_>, HandleError> {
+        self.display_handle()
+    }
+}
+
+impl<T> Sealed for EventLoop<T> {}
+
+impl<T> GlutinEventLoop for EventLoop<T> {
+    #[allow(deprecated)]
+    fn create_window(&self, window_attributes: WindowAttributes) -> Result<Window, OsError> {
+        self.create_window(window_attributes)
+    }
+
+    fn glutin_display_handle(&self) -> Result<DisplayHandle<'_>, HandleError> {
+        self.display_handle()
+    }
+}
diff --git a/glutin-winit/src/lib.rs b/glutin-winit/src/lib.rs
index 751fb8d692..00b9a8f23d 100644
--- a/glutin-winit/src/lib.rs
+++ b/glutin-winit/src/lib.rs
@@ -8,8 +8,10 @@
 #![deny(missing_docs)]
 #![cfg_attr(clippy, deny(warnings))]
 
+mod event_loop;
 mod window;
 
+use event_loop::GlutinEventLoop;
 pub use window::GlWindow;
 
 use std::error::Error;
@@ -23,9 +25,8 @@ use glutin::prelude::*;
 #[cfg(wgl_backend)]
 use raw_window_handle::HasWindowHandle;
 
-use raw_window_handle::{HasDisplayHandle, RawWindowHandle};
+use raw_window_handle::RawWindowHandle;
 use winit::error::OsError;
-use winit::event_loop::ActiveEventLoop;
 use winit::window::{Window, WindowAttributes};
 
 #[cfg(glx_backend)]
@@ -36,6 +37,13 @@ use winit::platform::x11::WindowAttributesExtX11;
 #[cfg(all(not(egl_backend), not(glx_backend), not(wgl_backend), not(cgl_backend)))]
 compile_error!("Please select at least one api backend");
 
+pub(crate) mod private {
+    /// Prevent traits from being implemented downstream, since those are used
+    /// purely for documentation organization and simplify platform api
+    /// implementation maintenance.
+    pub trait Sealed {}
+}
+
 /// The helper to perform [`Display`] creation and OpenGL platform
 /// bootstrapping with the help of [`winit`] with little to no platform specific
 /// code.
@@ -88,7 +96,7 @@ impl DisplayBuilder {
     /// otherwise only builtin functions like `glClear` will be available.
     pub fn build<Picker>(
         mut self,
-        event_loop: &ActiveEventLoop,
+        event_loop: &impl GlutinEventLoop,
         template_builder: ConfigTemplateBuilder,
         config_picker: Picker,
     ) -> Result<(Option<Window>, Config), Box<dyn Error>>
@@ -141,7 +149,7 @@ impl DisplayBuilder {
 }
 
 fn create_display(
-    event_loop: &ActiveEventLoop,
+    event_loop: &impl GlutinEventLoop,
     _api_preference: ApiPreference,
     _raw_window_handle: Option<RawWindowHandle>,
 ) -> Result<Display, Box<dyn Error>> {
@@ -173,7 +181,7 @@ fn create_display(
         ApiPreference::FallbackEgl => DisplayApiPreference::WglThenEgl(_raw_window_handle),
     };
 
-    let handle = event_loop.display_handle()?.as_raw();
+    let handle = event_loop.glutin_display_handle()?.as_raw();
     unsafe { Ok(Display::new(handle, _preference)?) }
 }
 
@@ -184,7 +192,7 @@ fn create_display(
 /// [`Window`]: winit::window::Window
 /// [`Config`]: glutin::config::Config
 pub fn finalize_window(
-    event_loop: &ActiveEventLoop,
+    event_loop: &impl GlutinEventLoop,
     mut attributes: WindowAttributes,
     gl_config: &Config,
 ) -> Result<Window, OsError> {