wayland: improve diagnostic of failed init (#512)

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Unreleased
 
 - `Icon::to_cardinals` is no longer public, since it was never supposed to be.
+- Wayland: improve diagnostics if initialization fails
 
 # Version 0.14.0 (2018-05-09)
 

Cargo.toml

@@ -51,7 +51,7 @@ features = [
 ]
 
 [target.'cfg(any(target_os = "linux", target_os = "dragonfly", target_os = "freebsd", target_os = "openbsd"))'.dependencies]
-wayland-client = { version = "0.20.4", features = [ "dlopen", "egl", "cursor"] }
+wayland-client = { version = "0.20.6", features = [ "dlopen", "egl", "cursor"] }
 smithay-client-toolkit = "0.2.1"
 x11-dl = "2.17.5"
 parking_lot = "0.5"

src/platform/linux/mod.rs

@@ -6,6 +6,8 @@ use std::ffi::CStr;
 use std::os::raw::*;
 use std::sync::Arc;
 
+use sctk::reexports::client::ConnectError;
+
 // `std::os::raw::c_void` and `libc::c_void` are NOT interchangeable!
 use libc;
 
@@ -395,10 +397,9 @@ r#"Failed to initialize any backend!
         panic!(err_string);
     }
 
-    pub fn new_wayland() -> Result<EventsLoop, ()> {
+    pub fn new_wayland() -> Result<EventsLoop, ConnectError> {
         wayland::EventsLoop::new()
             .map(EventsLoop::Wayland)
-            .ok_or(())
     }
 
     pub fn new_x11() -> Result<EventsLoop, XNotSupported> {

src/platform/linux/wayland/event_loop.rs

@@ -10,7 +10,7 @@ use super::window::WindowStore;
 
 use sctk::Environment;
 use sctk::output::OutputMgr;
-use sctk::reexports::client::{Display, EventQueue, GlobalEvent, Proxy};
+use sctk::reexports::client::{Display, EventQueue, GlobalEvent, Proxy, ConnectError};
 use sctk::reexports::client::commons::Implementation;
 use sctk::reexports::client::protocol::{wl_keyboard, wl_output, wl_pointer, wl_registry, wl_seat,
                                         wl_touch};
@@ -100,11 +100,8 @@ impl EventsLoopProxy {
 }
 
 impl EventsLoop {
-    pub fn new() -> Option<EventsLoop> {
+    pub fn new() -> Result<EventsLoop, ConnectError> {
-        let (display, mut event_queue) = match Display::connect_to_env() {
+        let (display, mut event_queue) = Display::connect_to_env()?;
-            Ok(ret) => ret,
-            Err(_) => return None,
-        };
 
         let sink = Arc::new(Mutex::new(EventsLoopSink::new()));
         let store = Arc::new(Mutex::new(WindowStore::new()));
@@ -120,7 +117,7 @@ impl EventsLoop {
             },
         ).unwrap();
 
-        Some(EventsLoop {
+        Ok(EventsLoop {
             display: Arc::new(display),
             evq: RefCell::new(event_queue),
             sink: sink,