Crate safina_select

This is a Rust library for awaiting multiple futures and getting the value of the first one that completes.

It is part of safina, a safe async runtime.

Features

• forbid(unsafe_code)
• Depends only on std
• Good test coverage (96%)
• Works with safina-executor or any async executor

Limitations

• Can await 2-5 futures. Nest them if you need more.

Examples

use safina_async_test::async_test;
use safina_select::{select_ab, OptionAb};
let conn = match select_ab(make_new(addr.clone()), get_from_pool(addr.clone())).await {
    OptionAb::A(result) => result?,
    OptionAb::B(result) => result?,
};
// When both futures return the same type, you can use `take`:
let conn = select_ab(make_new(addr.clone()), get_from_pool(addr.clone())).await.take()?;

use safina_async_test::async_test;
use safina_select::{select_ab, OptionAb};
safina_timer::start_timer_thread();
let data = match select_ab(read_data(), safina_timer::sleep_until(deadline)).await {
    OptionAb::A(result) => Ok(result?),
    OptionAb::B(()) => Err("timeout"),
};

Documentation

https://docs.rs/safina-select

TO DO - Alternatives

• tokio::select
  • very popular
  • Fast
  • internally incredibly complicated
  • full of unsafe
• futures::select
  • very popular
  • proc macro, very complicated
  • contains a little unsafe code

Changelog

• v0.1.3 - Rename OptionAB to OptionAb, etc.
• v0.1.2 - Satisfy pedantic clippy
• v0.1.1 - Add badges to readme. Rename safina package to safina-executor.
• v0.1.0 - First published version

TO DO

• DONE - Implement sleep_ab
• DONE - Add tests
• DONE - Add docs
• DONE - Add sleep_abc, sleep_abcd, and sleep_abcde
• DONE - Publish on crates.io

Release Process

1. Edit Cargo.toml and bump version number.
2. Run ./release.sh

Structs

SelectFuture

A future that polls two futures and returns the value from the one that completes first.

Enums

OptionAb
OptionAbc
OptionAbcd
OptionAbcde

Functions

select_ab	Awaits both futures and returns the value from the one that completes first.
select_abc	Awaits the futures and returns the value from the one that completes first.
select_abcd	Awaits the futures and returns the value from the one that completes first.
select_abcde	Awaits the futures and returns the value from the one that completes first.