Window wrapper for SDL2 and WGPU

wrapper.rs

use sdl2::video::Window;
use raw_window_handle::{HasRawWindowHandle, RawWindowHandle};
use raw_window_handle::AppKitHandle;

pub struct WindowWrapper<'a>(pub &'a Window);

unsafe impl<'a> HasRawWindowHandle for WindowWrapper<'a> {
    #[cfg(not(target_os = "macos"))]
    /// all non-mac platforms work correctly, so return the handle directly
    fn raw_window_handle(&self) -> RawWindowHandle {
        self.0.raw_window_handle()
    }

    #[cfg(target_os = "macos")]
    /// do some work on appkit to get the root NSView for the NSWindow returned by sdl2
    fn raw_window_handle(&self) -> RawWindowHandle {
        use objc::{msg_send, sel, sel_impl};
        use objc::runtime::Object;
        let handle = self.0.raw_window_handle();
        match handle {
                RawWindowHandle::AppKit(appkit_handle) => {
            unsafe {
                    let mut new_handle = appkit_handle.clone();
                    new_handle.ns_view = msg_send![appkit_handle.ns_window as *mut Object, contentView];
                    RawWindowHandle::AppKit(new_handle)
                }
            }
            _ => unreachable!()
        }
    }
}