fix: Implement raw-window-handle traits for X11Window (#50768)

Gary Tierney created 1 month ago

I'm embedding a 3D viewport inside GPUI by creating a child window with
its own surface that fits the bounds of a GPUI element, and I need
access to the raw window handle of the current window to manage it.
Right now on X11 this is stubbed as unimplemented and results in a
panic. I've copied most of the same implementation from the associated
`RawWindow` into `X11Window`.

Small clip of a Bevy app embedded inside GPUI with a popover that draws
above the 3d surface to show testing was done:


[Screencast_20260304_182657.webm](https://github.com/user-attachments/assets/829f9197-1613-41a7-af83-d377f3154751)


 
Before you mark this PR as ready for review, make sure that you have:
- [x] Added a solid test coverage and/or screenshots from doing manual
testing
- [ ] Done a self-review taking into account security and performance
aspects
- [ ] Aligned any UI changes with the [UI
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)

Release Notes:

- Added implementations of `rwh::HasDisplayHandle` and
`rwh::HasWindowHandle` for `X11Window`

Change summary

crates/gpui_linux/src/linux/x11/window.rs | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)

Detailed changes

crates/gpui_linux/src/linux/x11/window.rs

@@ -319,12 +319,28 @@ impl rwh::HasDisplayHandle for RawWindow {
 
 impl rwh::HasWindowHandle for X11Window {
     fn window_handle(&self) -> Result<rwh::WindowHandle<'_>, rwh::HandleError> {
-        unimplemented!()
+        let Some(non_zero) = NonZeroU32::new(self.0.x_window) else {
+            return Err(rwh::HandleError::Unavailable);
+        };
+        let handle = rwh::XcbWindowHandle::new(non_zero);
+        Ok(unsafe { rwh::WindowHandle::borrow_raw(handle.into()) })
     }
 }
+
 impl rwh::HasDisplayHandle for X11Window {
     fn display_handle(&self) -> Result<rwh::DisplayHandle<'_>, rwh::HandleError> {
-        unimplemented!()
+        let connection =
+            as_raw_xcb_connection::AsRawXcbConnection::as_raw_xcb_connection(&*self.0.xcb)
+                as *mut _;
+        let Some(non_zero) = NonNull::new(connection) else {
+            return Err(rwh::HandleError::Unavailable);
+        };
+        let screen_id = {
+            let state = self.0.state.borrow();
+            u32::from(state.display.id()) as i32
+        };
+        let handle = rwh::XcbDisplayHandle::new(Some(non_zero), screen_id);
+        Ok(unsafe { rwh::DisplayHandle::borrow_raw(handle.into()) })
     }
 }