feat: Add an owned display handle type

This was supposed to be rolled out with the rwh v0.6 update, but it
was left behind for some reason. I've added this type back.

Signed-off-by: John Nunley <dev@notgull.net>

src/platform_impl/linux/mod.rs

@@ -902,6 +902,15 @@ impl EventLoopWindowTarget {
         x11_or_wayland!(match self; Self(evlp) => evlp.exiting())
     }
 
+    pub(crate) fn owned_display_handle(&self) -> OwnedDisplayHandle {
+        match self {
+            #[cfg(x11_platform)]
+            Self::X(conn) => OwnedDisplayHandle::X(conn.x_connection().clone()),
+            #[cfg(wayland_platform)]
+            Self::Wayland(conn) => OwnedDisplayHandle::Wayland(conn.connection.clone()),
+        }
+    }
+
     fn set_exit_code(&self, code: i32) {
         x11_or_wayland!(match self; Self(evlp) => evlp.set_exit_code(code))
     }
@@ -911,6 +920,67 @@ impl EventLoopWindowTarget {
     }
 }
 
+#[derive(Clone)]
+#[allow(dead_code)]
+pub(crate) enum OwnedDisplayHandle {
+    #[cfg(x11_platform)]
+    X(Arc<XConnection>),
+    #[cfg(wayland_platform)]
+    Wayland(wayland_client::Connection),
+}
+
+impl OwnedDisplayHandle {
+    #[cfg(feature = "rwh_05")]
+    #[inline]
+    pub fn raw_display_handle_rwh_05(&self) -> rwh_05::RawDisplayHandle {
+        match self {
+            #[cfg(x11_platform)]
+            Self::X(xconn) => {
+                let mut xlib_handle = rwh_05::XlibDisplayHandle::empty();
+                xlib_handle.display = xconn.display.cast();
+                xlib_handle.screen = xconn.default_screen_index() as _;
+                xlib_handle.into()
+            }
+
+            #[cfg(wayland_platform)]
+            Self::Wayland(conn) => {
+                use sctk::reexports::client::Proxy;
+
+                let mut wayland_handle = rwh_05::WaylandDisplayHandle::empty();
+                wayland_handle.display = conn.display().id().as_ptr() as *mut _;
+                wayland_handle.into()
+            }
+        }
+    }
+
+    #[cfg(feature = "rwh_06")]
+    #[inline]
+    pub fn raw_display_handle_rwh_06(
+        &self,
+    ) -> Result<rwh_06::RawDisplayHandle, rwh_06::HandleError> {
+        use std::ptr::NonNull;
+
+        match self {
+            #[cfg(x11_platform)]
+            Self::X(xconn) => Ok(rwh_06::XlibDisplayHandle::new(
+                NonNull::new(xconn.display.cast()),
+                xconn.default_screen_index() as _,
+            )
+            .into()),
+
+            #[cfg(wayland_platform)]
+            Self::Wayland(conn) => {
+                use sctk::reexports::client::Proxy;
+
+                Ok(rwh_06::WaylandDisplayHandle::new(
+                    NonNull::new(conn.display().id().as_ptr().cast()).unwrap(),
+                )
+                .into())
+            }
+        }
+    }
+}
+
 /// Returns the minimum `Option<Duration>`, taking into account that `None`
 /// equates to an infinite timeout, not a zero timeout (so can't just use
 /// `Option::min`)