lune-packaging/src/lune/lua/process/mod.rs

use std::process::ExitStatus;

use mlua::prelude::*;
use tokio::{io, process::Child, task};

mod tee_writer;
use tee_writer::AsyncTeeWriter;

pub async fn pipe_and_inherit_child_process_stdio(
    mut child: Child,
) -> LuaResult<(ExitStatus, Vec<u8>, Vec<u8>)> {
    let mut child_stdout = child.stdout.take().unwrap();
    let mut child_stderr = child.stderr.take().unwrap();

    /*
        NOTE: We do not need to register these
        independent tasks spawning in the scheduler

        This function is only used by `process.spawn` which in
        turn registers a task with the scheduler that awaits this
    */

    let stdout_thread = task::spawn(async move {
        let mut stdout = io::stdout();
        let mut tee = AsyncTeeWriter::new(&mut stdout);

        io::copy(&mut child_stdout, &mut tee)
            .await
            .map_err(LuaError::external)?;

        Ok::<_, LuaError>(tee.into_vec())
    });

    let stderr_thread = task::spawn(async move {
        let mut stderr = io::stderr();
        let mut tee = AsyncTeeWriter::new(&mut stderr);

        io::copy(&mut child_stderr, &mut tee)
            .await
            .map_err(LuaError::external)?;

        Ok::<_, LuaError>(tee.into_vec())
    });

    let status = child.wait().await.expect("Child process failed to start");

    let stdout_buffer = stdout_thread.await.expect("Tee writer for stdout errored");
    let stderr_buffer = stderr_thread.await.expect("Tee writer for stderr errored");

    Ok::<_, LuaError>((status, stdout_buffer?, stderr_buffer?))
}