1use std::path::PathBuf;
  2use std::pin::Pin;
  3
  4use anyhow::{Context as _, Result};
  5use async_trait::async_trait;
  6use futures::io::{BufReader, BufWriter};
  7use futures::{
  8    AsyncBufReadExt as _, AsyncRead, AsyncWrite, AsyncWriteExt as _, Stream, StreamExt as _,
  9};
 10use gpui::AsyncApp;
 11use smol::channel;
 12use smol::process::Child;
 13use util::TryFutureExt as _;
 14
 15use crate::client::ModelContextServerBinary;
 16use crate::transport::Transport;
 17
 18pub struct StdioTransport {
 19    stdout_sender: channel::Sender<String>,
 20    stdin_receiver: channel::Receiver<String>,
 21    stderr_receiver: channel::Receiver<String>,
 22    server: Child,
 23}
 24
 25impl StdioTransport {
 26    pub fn new(
 27        binary: ModelContextServerBinary,
 28        working_directory: &Option<PathBuf>,
 29        cx: &AsyncApp,
 30    ) -> Result<Self> {
 31        let mut command = util::command::new_smol_command(&binary.executable);
 32        command
 33            .args(&binary.args)
 34            .envs(binary.env.unwrap_or_default())
 35            .stdin(std::process::Stdio::piped())
 36            .stdout(std::process::Stdio::piped())
 37            .stderr(std::process::Stdio::piped())
 38            .kill_on_drop(true);
 39
 40        if let Some(working_directory) = working_directory {
 41            command.current_dir(working_directory);
 42        }
 43
 44        let mut server = command
 45            .spawn()
 46            .with_context(|| format!("failed to spawn command {command:?})",))?;
 47
 48        let stdin = server.stdin.take().unwrap();
 49        let stdout = server.stdout.take().unwrap();
 50        let stderr = server.stderr.take().unwrap();
 51
 52        let (stdin_sender, stdin_receiver) = channel::unbounded::<String>();
 53        let (stdout_sender, stdout_receiver) = channel::unbounded::<String>();
 54        let (stderr_sender, stderr_receiver) = channel::unbounded::<String>();
 55
 56        cx.spawn(async move |_| Self::handle_output(stdin, stdout_receiver).log_err().await)
 57            .detach();
 58
 59        cx.spawn(async move |_| Self::handle_input(stdout, stdin_sender).await)
 60            .detach();
 61
 62        cx.spawn(async move |_| Self::handle_err(stderr, stderr_sender).await)
 63            .detach();
 64
 65        Ok(Self {
 66            stdout_sender,
 67            stdin_receiver,
 68            stderr_receiver,
 69            server,
 70        })
 71    }
 72
 73    async fn handle_input<Stdout>(stdin: Stdout, inbound_rx: channel::Sender<String>)
 74    where
 75        Stdout: AsyncRead + Unpin + Send + 'static,
 76    {
 77        let mut stdin = BufReader::new(stdin);
 78        let mut line = String::new();
 79        while let Ok(n) = stdin.read_line(&mut line).await {
 80            if n == 0 {
 81                break;
 82            }
 83            if inbound_rx.send(line.clone()).await.is_err() {
 84                break;
 85            }
 86            line.clear();
 87        }
 88    }
 89
 90    async fn handle_output<Stdin>(
 91        stdin: Stdin,
 92        outbound_rx: channel::Receiver<String>,
 93    ) -> Result<()>
 94    where
 95        Stdin: AsyncWrite + Unpin + Send + 'static,
 96    {
 97        let mut stdin = BufWriter::new(stdin);
 98        let mut pinned_rx = Box::pin(outbound_rx);
 99        while let Some(message) = pinned_rx.next().await {
100            log::trace!("outgoing message: {}", message);
101
102            stdin.write_all(message.as_bytes()).await?;
103            stdin.write_all(b"\n").await?;
104            stdin.flush().await?;
105        }
106        Ok(())
107    }
108
109    async fn handle_err<Stderr>(stderr: Stderr, stderr_tx: channel::Sender<String>)
110    where
111        Stderr: AsyncRead + Unpin + Send + 'static,
112    {
113        let mut stderr = BufReader::new(stderr);
114        let mut line = String::new();
115        while let Ok(n) = stderr.read_line(&mut line).await {
116            if n == 0 {
117                break;
118            }
119            if stderr_tx.send(line.clone()).await.is_err() {
120                break;
121            }
122            line.clear();
123        }
124    }
125}
126
127#[async_trait]
128impl Transport for StdioTransport {
129    async fn send(&self, message: String) -> Result<()> {
130        Ok(self.stdout_sender.send(message).await?)
131    }
132
133    fn receive(&self) -> Pin<Box<dyn Stream<Item = String> + Send>> {
134        Box::pin(self.stdin_receiver.clone())
135    }
136
137    fn receive_err(&self) -> Pin<Box<dyn Stream<Item = String> + Send>> {
138        Box::pin(self.stderr_receiver.clone())
139    }
140}
141
142impl Drop for StdioTransport {
143    fn drop(&mut self) {
144        let _ = self.server.kill();
145    }
146}