Return a XNotSupported for new_x11()

Author: tomaka

src/os/unix.rs

@@ -12,26 +12,23 @@ use WindowBuilder;
 use platform::x11::XConnection;
 use platform::x11::ffi::XVisualInfo;
 
-pub use platform::x11;
+pub use platform::XNotSupported;
 
 /// Additional methods on `EventsLoop` that are specific to Linux.
 pub trait EventsLoopExt {
     /// Builds a new `EventsLoop` that is forced to use X11.
-    fn new_x11() -> Self;
+    fn new_x11() -> Result<Self, XNotSupported>
+        where Self: Sized;
 
     /// Builds a new `EventsLoop` that is forced to use Wayland.
-    fn new_wayland() -> Self;
+    fn new_wayland() -> Self
+        where Self: Sized;
 }
 
 impl EventsLoopExt for EventsLoop {
     #[inline]
-    fn new_x11() -> Self {
-        EventsLoop {
-            events_loop: match LinuxEventsLoop::new_x11() {
-                Ok(e) => e,
-                Err(_) => panic!()      // TODO: propagate
-            }
-        }
+    fn new_x11() -> Result<Self, XNotSupported> {
+        LinuxEventsLoop::new_x11().map(|ev| EventsLoop { events_loop: ev })
     }
 
     #[inline]

src/platform/linux/mod.rs

@@ -9,9 +9,10 @@ use libc;
 
 use self::x11::XConnection;
 use self::x11::XError;
-use self::x11::XNotSupported;
 use self::x11::ffi::XVisualInfo;
 
+pub use self::x11::XNotSupported;
+
 mod dlopen;
 pub mod wayland;
 pub mod x11;
@@ -285,10 +286,7 @@ impl EventsLoop {
         if let Ok(env_var) = env::var(BACKEND_PREFERENCE_ENV_VAR) {
             match env_var.as_str() {
                 "x11" => {
-                    match EventsLoop::new_x11() {
-                        Ok(e) => return e,
-                        Err(_) => panic!()      // TODO: propagate
-                    }
+                    return EventsLoop::new_x11().unwrap();      // TODO: propagate
                 },
                 "wayland" => {
                     match EventsLoop::new_wayland() {
@@ -318,12 +316,11 @@ impl EventsLoop {
             .ok_or(())
     }
 
-    pub fn new_x11() -> Result<EventsLoop, ()> {
-        if let Ok(ref x) = *X11_BACKEND {
-            return Ok(EventsLoop::X(x11::EventsLoop::new(x.clone())));
+    pub fn new_x11() -> Result<EventsLoop, XNotSupported> {
+        match *X11_BACKEND {
+            Ok(ref x) => Ok(EventsLoop::X(x11::EventsLoop::new(x.clone()))),
+            Err(ref err) => Err(err.clone()),
         }
-
-        Err(())
     }
 
     #[inline]