Add ability to get wayland display from events loop. (#829)

Signed-off-by: Hal Gentz <zegentzy@protonmail.com>

CHANGELOG.md

@@ -37,7 +37,7 @@
     - `LoopDestroyed` is emitted when the `run` or `run_return` method is about to exit.
 - Rename `MonitorId` to `MonitorHandle`.
 - Removed `serde` implementations from `ControlFlow`.
-
+- On Wayland, added a `get_wayland_display` function to `EventsLoopExt`.
 - On Windows, fix `CursorMoved(0, 0)` getting dispatched on window focus.
 - On macOS, fix command key event left and right reverse.
 - On FreeBSD, NetBSD, and OpenBSD, fix build of X11 backend.

src/platform/unix.rs

@@ -111,6 +111,13 @@ pub trait EventLoopExtUnix {
 
     //#[doc(hidden)]
     //fn get_xlib_xconnection(&self) -> Option<Arc<XConnection>>;
+
+    /// Returns a pointer to the `wl_display` object of wayland that is used by this `EventsLoop`.
+    ///
+    /// Returns `None` if the `EventsLoop` doesn't use wayland (if it uses xlib for example).
+    ///
+    /// The pointer will become invalid when the glutin `EventsLoop` is destroyed.
+    fn get_wayland_display(&self) -> Option<*mut raw::c_void>;
 }
 
 impl<T> EventLoopExtUnix for EventLoop<T> {
@@ -150,6 +157,14 @@ impl<T> EventLoopExtUnix for EventLoop<T> {
     //fn get_xlib_xconnection(&self) -> Option<Arc<XConnection>> {
     //    self.event_loop.x_connection().cloned()
     //}
+
+    #[inline]
+    fn get_wayland_display(&self) -> Option<*mut raw::c_void> {
+        match self.events_loop {
+            LinuxEventsLoop::Wayland(ref e) => Some(e.get_display().c_ptr() as *mut _),
+            _ => None
+        }
+    }
 }
 
 /// Additional methods on `Window` that are specific to Unix.

src/platform_impl/linux/wayland/event_loop.rs

@@ -287,6 +287,10 @@ impl<T: 'static> EventLoop<T> {
         get_available_monitors(&self.outputs)
     }
 
+    pub fn get_display(&self) -> &Display {
+        &*self.display
+    }
+
     pub fn window_target(&self) -> &RootELW<T> {
         &self.window_target
     }