1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
use futures::sink::Sink as _;
use snafu::ResultExt as _;
#[derive(Debug, snafu::Snafu)]
pub enum Error {
#[snafu(display("failed to read from event channel: {}", source))]
ReadChannel {
source: tokio::sync::mpsc::error::UnboundedRecvError,
},
#[snafu(display(
"failed to spawn a background thread to read terminal input: {}",
source
))]
TerminalInputReadingThread { source: std::io::Error },
}
pub struct KeyReader {
events: Option<
tokio::sync::mpsc::UnboundedReceiver<crossterm::input::InputEvent>,
>,
quit: Option<tokio::sync::oneshot::Sender<()>>,
}
impl KeyReader {
pub fn new() -> Self {
Self {
events: None,
quit: None,
}
}
}
impl futures::stream::Stream for KeyReader {
type Item = crossterm::input::InputEvent;
type Error = Error;
fn poll(&mut self) -> futures::Poll<Option<Self::Item>, Self::Error> {
if self.events.is_none() {
let task = futures::task::current();
let reader = crossterm::input::input().read_sync();
let (events_tx, events_rx) =
tokio::sync::mpsc::unbounded_channel();
let mut events_tx = events_tx.wait();
let (quit_tx, mut quit_rx) = tokio::sync::oneshot::channel();
// TODO: this is pretty janky - it'd be better to build in more
// useful support to crossterm directly
std::thread::Builder::new()
.spawn(move || {
for event in reader {
// unwrap is unpleasant, but so is figuring out how to
// propagate the error back to the main thread
events_tx.send(event).unwrap();
task.notify();
if quit_rx.try_recv().is_ok() {
break;
}
}
})
.context(TerminalInputReadingThread)?;
self.events = Some(events_rx);
self.quit = Some(quit_tx);
}
self.events.as_mut().unwrap().poll().context(ReadChannel)
}
}
impl Drop for KeyReader {
fn drop(&mut self) {
if let Some(quit_tx) = self.quit.take() {
// don't care if it fails to send, this can happen if the thread
// terminates due to seeing a newline before the keyreader goes
// out of scope
let _ = quit_tx.send(());
}
}
}
|