polyp/
protocol.rs

1use std::io::{self, BufRead, BufReader, Stdin, Stdout, Write};
2use std::process::{Child, ChildStdin, ChildStdout};
3
4pub struct Connection<Source: BufRead, Sink: Write> {
5    source: Source,
6    sink: Sink,
7}
8
9impl<Source: BufRead, Sink: Write> Connection<Source, Sink> {
10    pub fn new(source: Source, sink: Sink) -> Self {
11        Self { source, sink }
12    }
13}
14
15impl Connection<BufReader<ChildStdout>, ChildStdin> {
16    pub fn new_from_child(child: Child) -> Option<Self> {
17        let stdin = child.stdin?;
18        let stdout = child.stdout?;
19
20        Some(Self {
21            source: BufReader::new(stdout),
22            sink: stdin,
23        })
24    }
25}
26
27impl Connection<BufReader<Stdin>, Stdout> {
28    pub fn new_from_current_process() -> Self {
29        Self {
30            source: BufReader::new(io::stdin()),
31            sink: io::stdout(),
32        }
33    }
34}
35
36impl<Source: BufRead, Sink: Write> Connection<Source, Sink> {
37    pub fn recv_message<T: serde::de::DeserializeOwned>(&mut self) -> Result<T, MessageIoError> {
38        let mut buf = String::new();
39
40        self.source
41            .read_line(&mut buf)
42            .map_err(MessageIoError::Recv)?;
43
44        Ok(serde_json::from_str(&buf)?)
45    }
46
47    pub fn send_message<T: serde::Serialize>(&mut self, t: &T) -> Result<(), MessageIoError> {
48        let json = serde_json::to_vec(t)?;
49        self.sink.write_all(&json).map_err(MessageIoError::Send)?;
50        self.sink.write_all(b"\n").map_err(MessageIoError::Send)?;
51
52        Ok(())
53    }
54}
55
56#[derive(Debug, thiserror::Error)]
57pub enum MessageIoError {
58    #[error("failed receiving message from source")]
59    Recv(io::Error),
60    #[error("failed sending message to sink")]
61    Send(io::Error),
62    #[error("failed deserializing JSON")]
63    Json(#[from] serde_json::Error),
64}
polyp/protocol.rs

polyp/
protocol.rs
