termion_input_tokio/
lib.rs

1use std::{future, io, pin::Pin};
2use std::{
3    iter::empty,
4    task::{Context, Poll},
5};
6
7use bytes::{Buf, Bytes, BytesMut};
8use futures::{Stream, StreamExt, stream::BoxStream};
9use termion::event::{self, Event, Key};
10use tokio::io::AsyncRead;
11use tokio_util::codec::{Decoder, FramedRead};
12
13/// An iterator over input events and the bytes that define them
14type EventsAndRawStream<R> = FramedRead<R, EventsAndRawDecoder>;
15
16pub struct EventsAndRawDecoder;
17
18impl Decoder for EventsAndRawDecoder {
19    type Item = (Event, Vec<u8>);
20    type Error = io::Error;
21
22    fn decode(&mut self, src: &mut BytesMut) -> Result<Option<Self::Item>, Self::Error> {
23        match src.len() {
24            0 => Ok(None),
25            1 => match src[0] {
26                b'\x1B' => {
27                    src.advance(1);
28                    Ok(Some((Event::Key(Key::Esc), vec![b'\x1B'])))
29                }
30                c => {
31                    if let Ok(res) = parse_event(c, &mut empty()) {
32                        src.advance(1);
33                        Ok(Some(res))
34                    } else {
35                        Ok(None)
36                    }
37                }
38            },
39            _ => {
40                let (off, res) = if let Some((c, cs)) = src.split_first() {
41                    let cur = Bytes::copy_from_slice(cs);
42                    let mut it = cur.into_iter().map(Ok);
43                    if let Ok(res) = parse_event(*c, &mut it) {
44                        (1 + cs.len() - it.len(), Ok(Some(res)))
45                    } else {
46                        (0, Ok(None))
47                    }
48                } else {
49                    (0, Ok(None))
50                };
51
52                src.advance(off);
53                res
54            }
55        }
56    }
57}
58
59fn parse_event<I>(item: u8, iter: &mut I) -> Result<(Event, Vec<u8>), io::Error>
60where
61    I: Iterator<Item = Result<u8, io::Error>>,
62{
63    let mut buf = vec![item];
64    let result = {
65        let mut iter = iter.inspect(|byte| {
66            if let &Ok(byte) = byte {
67                buf.push(byte);
68            }
69        });
70        event::parse_event(item, &mut iter)
71    };
72    result
73        .or(Ok(Event::Unsupported(buf.clone())))
74        .map(|e| (e, buf))
75}
76
77// A type-erased stream of input events
78pub struct InputStream<T>(BoxStream<'static, Result<T, io::Error>>);
79
80impl<T> InputStream<T> {
81    fn new<S: Stream<Item = Result<T, io::Error>> + Send + 'static>(stream: S) -> Self {
82        InputStream(Box::pin(stream))
83    }
84}
85
86impl<T> Stream for InputStream<T> {
87    type Item = Result<T, io::Error>;
88
89    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
90        self.0.poll_next_unpin(cx)
91    }
92}
93
94/// Extension to `Read` trait that provides streams derived from input events.
95pub trait TermReadAsync: Sized {
96    /// An iterator over input events.
97    fn events_stream(self) -> InputStream<Event>;
98
99    /// An iterator over key inputs.
100    fn keys_stream(self) -> InputStream<Key>;
101
102    /// An iterator over input events and the bytes that define them.
103    fn events_and_raw_stream(self) -> EventsAndRawStream<Self>
104    where
105        Self: Sized;
106}
107
108impl<R: 'static + Send + AsyncRead> TermReadAsync for R {
109    fn events_stream(self) -> InputStream<Event> {
110        InputStream::new(
111            self.events_and_raw_stream()
112                .map(|event_and_raw| match event_and_raw {
113                    Ok((event, _raw)) => Ok(event),
114                    Err(e) => Err(e),
115                }),
116        )
117    }
118
119    fn keys_stream(self) -> InputStream<Key> {
120        InputStream::new(self.events_stream().filter_map(|event| {
121            future::ready(match event {
122                Ok(Event::Key(k)) => Some(Ok(k)),
123                Ok(_) => None,
124                Err(e) => Some(Err(e)),
125            })
126        }))
127    }
128
129    fn events_and_raw_stream(self) -> EventsAndRawStream<Self> {
130        FramedRead::new(self, EventsAndRawDecoder)
131    }
132}
termion_input_tokio/lib.rs

termion_input_tokio/
lib.rs
