Allow input capture & emulation being disabled (#158)

* Input capture and emulation can now be disabled and will prompt the user to enable again.

* Improved error handling to deliver more useful error messages

input-capture/src/dummy.rs

@@ -1,11 +1,13 @@
-use std::io;
 use std::pin::Pin;
 use std::task::{Context, Poll};
 
+use async_trait::async_trait;
 use futures_core::Stream;
 
 use input_event::Event;
 
+use crate::CaptureError;
+
 use super::{CaptureHandle, InputCapture, Position};
 
 pub struct DummyInputCapture {}
@@ -22,22 +24,27 @@ impl Default for DummyInputCapture {
     }
 }
 
+#[async_trait]
 impl InputCapture for DummyInputCapture {
-    fn create(&mut self, _handle: CaptureHandle, _pos: Position) -> io::Result<()> {
+    async fn create(&mut self, _handle: CaptureHandle, _pos: Position) -> Result<(), CaptureError> {
         Ok(())
     }
 
-    fn destroy(&mut self, _handle: CaptureHandle) -> io::Result<()> {
+    async fn destroy(&mut self, _handle: CaptureHandle) -> Result<(), CaptureError> {
         Ok(())
     }
 
-    fn release(&mut self) -> io::Result<()> {
+    async fn release(&mut self) -> Result<(), CaptureError> {
+        Ok(())
+    }
+
+    async fn terminate(&mut self) -> Result<(), CaptureError> {
         Ok(())
     }
 }
 
 impl Stream for DummyInputCapture {
-    type Item = io::Result<(CaptureHandle, Event)>;
+    type Item = Result<(CaptureHandle, Event), CaptureError>;
 
     fn poll_next(self: Pin<&mut Self>, _cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
         Poll::Pending