I/O Stream

Set of I/O-free Rust coroutines and runtimes to manage streams.

This library allows you to manage streams using an I/O-agnostic approach, based on 3 concepts:

Coroutine

A coroutine is an I/O-free, resumable and composable state machine that emits I/O requests. A coroutine is considered terminated when it does not emit I/O requests anymore.

See available coroutines at ./src/coroutines.

Runtime

A runtime contains all the I/O logic, and is responsible for processing I/O requests emitted by coroutines.

See available runtimes at ./src/runtimes.

Loop

The loop is the glue between coroutines and runtimes. It makes the coroutine progress while allowing runtime to process I/O.

Examples

See complete examples at ./examples.

Read stdin synchronously

use io_stream::{coroutines::Read, runtimes::std::handle};

let mut stdin = std::io::stdin();

let mut arg = None;
let mut read = Read::new(&mut buffer);

let output = loop {
    match read.resume(arg) {
        Ok(output) => break output,
        Err(io) => arg = Some(handle(&mut stdin, io).unwrap()),
    }
};

// same as &output.buffer[..output.bytes_count]
let bytes = output.bytes();

Write TCP stream asynchronously

use tokio::net::TcpStream;
use io_stream::{coroutines::Write, runtimes::tokio::handle};

let mut tcp = TcpStream::connect("127.0.0.1:1234").await.unwrap();

let mut arg = None;
let mut write = Write::new(b"bytes".to_vec());

while let Err(io) = write.resume(arg) {
    arg = Some(handle(&mut tcp, io).await.unwrap());
}

More examples

Have a look at projects built on the top of this library:

• starttls: I/O-free coroutine to upgrade any plain stream to a secure one
• time: Set of I/O-free coroutines to manage timers
• comodoro: CLI to manage timers

Sponsoring

Special thanks to the NLnet foundation and the European Commission that helped the project to receive financial support from various programs:

• NGI Assure in 2022
• NGI Zero Entrust in 2023
• NGI Zero Core in 2024 (still ongoing)

If you appreciate the project, feel free to donate using one of the following providers: