nb

Minimal and reusable non-blocking I/O layer

This project is developed and maintained by the HAL team.

Documentation

The ultimate goal of this crate is code reuse. With this crate you can write core I/O APIs that can then be adapted to operate in either blocking or non-blocking manner. Furthermore those APIs are not tied to a particular asynchronous model and can be adapted to work with the futures model or with the async / await model.

Core idea

The WouldBlock error variant signals that the operation can't be completed right now and would need to block to complete. WouldBlock is a special error in the sense that's not fatal; the operation can still be completed by retrying again later.

nb::Result is based on the API of std::io::Result, which has a WouldBlock variant in its ErrorKind.

We can map WouldBlock to different blocking and non-blocking models:

• In blocking mode: WouldBlock means try again right now (i.e. busy wait)
• In futures mode: WouldBlock means Async::NotReady
• In await mode: WouldBlock means yield (suspend the generator)

Minimum Supported Rust Version (MSRV)

This crate is guaranteed to compile on stable Rust 1.62 and up. It might compile with older versions but that may change in any new patch release.

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Code of Conduct

Contribution to this crate is organized under the terms of the Rust Code of Conduct, the maintainer of this crate, the HAL team, promises to intervene to uphold that code of conduct.