Async (#30)

- manual eventloop now replaced by asycn-await using the tokio runtime
- dns no longer blocks the event loop
- simplifies logic
- makes xdg-desktop-portal easier to integrate

src/producer.rs

@@ -1,5 +1,11 @@
-use mio::event::Source;
-use std::{error::Error, vec::Drain};
+use std::error::Error;
+
+#[cfg(unix)]
+use std::{io, os::fd::RawFd, vec::Drain};
+
+#[cfg(unix)]
+use tokio::io::unix::AsyncFd;
+
 use crate::{client::{ClientHandle, ClientEvent}, event::Event};
 use crate::backend::producer;
 
@@ -49,15 +55,24 @@ pub fn create() -> Result<Box<dyn EventProducer>, Box<dyn Error>> {
     }
 }
 
-pub trait EventProducer: Source {
+pub trait EventProducer {
+
     /// notify event producer of configuration changes
     fn notify(&mut self, event: ClientEvent);
 
+    /// release mouse
+    fn release(&mut self);
+
+    /// unix only
+    #[cfg(unix)]
+    fn get_async_fd(&self) -> io::Result<AsyncFd<RawFd>>;
+
     /// read an event
     /// this function must be invoked to retrieve an Event after
     /// the eventfd indicates a pending Event
+    #[cfg(unix)]
     fn read_events(&mut self) -> Drain<(ClientHandle, Event)>;
 
-    /// release mouse
-    fn release(&mut self);
+    #[cfg(not(unix))]
+    fn get_wait_channel(&mut self) -> Option<tokio::sync::mpsc::Receiver<(ClientHandle, Event)>>;
 }