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use futures::future::{Future, IntoFuture};
use futures::stream::Stream;
use std::io::Write;
#[derive(Debug)]
enum Error {
ReadError(crate::readline::Error),
EvalError(crate::process::Error),
PrintError(std::io::Error),
}
pub fn repl() {
let loop_stream = futures::stream::unfold(false, |done| {
if done {
return None;
}
let repl = read().and_then(|line| {
eval(&line).and_then(|(out, status)| {
out
// print the results as they come in
.and_then(|out| print(&out))
// wait for all output to be finished
.collect()
// ignore io errors since we just keep reading even after
// the process exits and the other end of the pty is
// closed
.or_else(|_| futures::future::ok(vec![]))
// once the output is all processed, then wait on the
// process to exit
.and_then(|_| status)
})
});
Some(repl.then(move |res| match res {
Ok(status) => {
eprint!("process exited with status {}\r\n", status);
return Ok((done, false));
}
Err(Error::ReadError(crate::readline::Error::EOF)) => {
return Ok((done, true));
}
Err(e) => {
let stderr = std::io::stderr();
let mut stderr = stderr.lock();
write!(stderr, "error: {:?}\r\n", e).unwrap();
stderr.flush().unwrap();
return Err(());
}
}))
});
tokio::run(loop_stream.collect().map(|_| ()));
}
fn read() -> impl futures::future::Future<Item = String, Error = Error> {
crate::readline::readline("$ ", true).map_err(|e| Error::ReadError(e))
}
fn eval(
line: &str,
) -> impl futures::future::Future<
Item = (
impl futures::stream::Stream<Item = Vec<u8>, Error = Error>,
impl futures::future::Future<
Item = std::process::ExitStatus,
Error = Error,
>,
),
Error = Error,
> {
match crate::process::spawn(line) {
Ok((out, status)) => Ok((
out.map_err(|e| Error::EvalError(e)),
status.map_err(|e| Error::EvalError(e)),
)),
Err(e) => Err(e).map_err(|e| Error::EvalError(e)),
}
.into_future()
}
fn print(out: &[u8]) -> Result<(), Error> {
let stdout = std::io::stdout();
let mut stdout = stdout.lock();
stdout.write(out).map_err(|e| Error::PrintError(e))?;
stdout.flush().map_err(|e| Error::PrintError(e))
}
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