#![deny( missing_docs, missing_debug_implementations, rust_2018_idioms, unused_imports, dead_code )] #![cfg_attr(docsrs, feature(doc_cfg))] // Disallow warnings when running tests. #![cfg_attr(test, deny(warnings))] // Disallow warnings in examples. #![doc(test(attr(deny(warnings))))] //! Mio is a fast, low-level I/O library for Rust focusing on non-blocking APIs //! and event notification for building high performance I/O apps with as little //! overhead as possible over the OS abstractions. //! //! # Usage //! //! Using Mio starts by creating a [`Poll`], which reads events from the OS and //! puts them into [`Events`]. You can handle I/O events from the OS with it. //! //! For more detail, see [`Poll`]. //! //! [`Poll`]: ../mio/struct.Poll.html //! [`Events`]: ../mio/event/struct.Events.html //! //! ## Examples //! //! Examples can found in the `examples` directory of the source code, or [on //! GitHub]. //! //! [on GitHub]: https://github.com/tokio-rs/mio/tree/master/examples //! //! ## Guide //! //! A getting started guide is available in the [`guide`] module. //! //! ## Available features //! //! The available features are described in the [`features`] module. // macros used internally #[macro_use] mod macros; mod interest; mod poll; mod sys; mod token; #[cfg(not(target_os = "wasi"))] mod waker; pub mod event; cfg_io_source! { mod io_source; } cfg_net! { pub mod net; } #[doc(no_inline)] pub use event::Events; pub use interest::Interest; pub use poll::{Poll, Registry}; pub use token::Token; #[cfg(not(target_os = "wasi"))] pub use waker::Waker; #[cfg(all(unix, feature = "os-ext"))] #[cfg_attr(docsrs, doc(cfg(all(unix, feature = "os-ext"))))] pub mod unix { //! Unix only extensions. pub mod pipe { //! Unix pipe. //! //! See the [`new`] function for documentation. pub use crate::sys::pipe::{new, Receiver, Sender}; } pub use crate::sys::SourceFd; } #[cfg(all(windows, feature = "os-ext"))] #[cfg_attr(docsrs, doc(cfg(all(windows, feature = "os-ext"))))] pub mod windows { //! Windows only extensions. pub use crate::sys::named_pipe::NamedPipe; } pub mod features { //! # Mio's optional features. //! //! This document describes the available features in Mio. //! #![cfg_attr(feature = "os-poll", doc = "## `os-poll` (enabled)")] #![cfg_attr(not(feature = "os-poll"), doc = "## `os-poll` (disabled)")] //! //! Mio by default provides only a shell implementation that `panic!`s the //! moment it is actually run. To run it requires OS support, this is //! enabled by activating the `os-poll` feature. //! //! This makes `Poll`, `Registry` and `Waker` functional. //! #![cfg_attr(feature = "os-ext", doc = "## `os-ext` (enabled)")] #![cfg_attr(not(feature = "os-ext"), doc = "## `os-ext` (disabled)")] //! //! `os-ext` enables additional OS specific facilities. These facilities can //! be found in the `unix` and `windows` module. //! #![cfg_attr(feature = "net", doc = "## Network types (enabled)")] #![cfg_attr(not(feature = "net"), doc = "## Network types (disabled)")] //! //! The `net` feature enables networking primitives in the `net` module. } pub mod guide { //! # Getting started guide. //! //! In this guide we'll do the following: //! //! 1. Create a [`Poll`] instance (and learn what it is). //! 2. Register an [event source]. //! 3. Create an event loop. //! //! At the end you'll have a very small (but quick) TCP server that accepts //! connections and then drops (disconnects) them. //! //! ## 1. Creating a `Poll` instance //! //! Using Mio starts by creating a [`Poll`] instance, which monitors events //! from the OS and puts them into [`Events`]. This allows us to execute I/O //! operations based on what operations are ready. //! //! [`Poll`]: ../struct.Poll.html //! [`Events`]: ../event/struct.Events.html //! #![cfg_attr(feature = "os-poll", doc = "```")] #![cfg_attr(not(feature = "os-poll"), doc = "```ignore")] //! # use mio::{Poll, Events}; //! # fn main() -> std::io::Result<()> { //! // `Poll` allows for polling of readiness events. //! let poll = Poll::new()?; //! // `Events` is collection of readiness `Event`s and can be filled by //! // calling `Poll::poll`. //! let events = Events::with_capacity(128); //! # drop((poll, events)); //! # Ok(()) //! # } //! ``` //! //! For example if we're using a [`TcpListener`], we'll only want to //! attempt to accept an incoming connection *iff* any connections are //! queued and ready to be accepted. We don't want to waste our time if no //! connections are ready. //! //! [`TcpListener`]: ../net/struct.TcpListener.html //! //! ## 2. Registering event source //! //! After we've created a [`Poll`] instance that monitors events from the OS //! for us, we need to provide it with a source of events. This is done by //! registering an [event source]. As the name “event source” suggests it is //! a source of events which can be polled using a `Poll` instance. On Unix //! systems this is usually a file descriptor, or a socket/handle on //! Windows. //! //! In the example below we'll use a [`TcpListener`] for which we'll receive //! an event (from [`Poll`]) once a connection is ready to be accepted. //! //! [event source]: ../event/trait.Source.html //! #![cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")] #![cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")] //! # use mio::net::TcpListener; //! # use mio::{Poll, Token, Interest}; //! # fn main() -> std::io::Result<()> { //! # let poll = Poll::new()?; //! # let address = "127.0.0.1:0".parse().unwrap(); //! // Create a `TcpListener`, binding it to `address`. //! let mut listener = TcpListener::bind(address)?; //! //! // Next we register it with `Poll` to receive events for it. The `SERVER` //! // `Token` is used to determine that we received an event for the listener //! // later on. //! const SERVER: Token = Token(0); //! poll.registry().register(&mut listener, SERVER, Interest::READABLE)?; //! # Ok(()) //! # } //! ``` //! //! Multiple event sources can be [registered] (concurrently), so we can //! monitor multiple sources at a time. //! //! [registered]: ../struct.Registry.html#method.register //! //! ## 3. Creating the event loop //! //! After we've created a [`Poll`] instance and registered one or more //! [event sources] with it, we can [poll] it for events. Polling for events //! is simple, we need a container to store the events: [`Events`] and need //! to do something based on the polled events (this part is up to you, we //! can't do it all!). If we do this in a loop we've got ourselves an event //! loop. //! //! The example below shows the event loop in action, completing our small //! TCP server. //! //! [poll]: ../struct.Poll.html#method.poll //! [event sources]: ../event/trait.Source.html //! #![cfg_attr(all(feature = "os-poll", feature = "net"), doc = "```")] #![cfg_attr(not(all(feature = "os-poll", feature = "net")), doc = "```ignore")] //! # use std::io; //! # use std::time::Duration; //! # use mio::net::TcpListener; //! # use mio::{Poll, Token, Interest, Events}; //! # fn main() -> io::Result<()> { //! # let mut poll = Poll::new()?; //! # let mut events = Events::with_capacity(128); //! # let address = "127.0.0.1:0".parse().unwrap(); //! # let mut listener = TcpListener::bind(address)?; //! # const SERVER: Token = Token(0); //! # poll.registry().register(&mut listener, SERVER, Interest::READABLE)?; //! // Start our event loop. //! loop { //! // Poll the OS for events, waiting at most 100 milliseconds. //! poll.poll(&mut events, Some(Duration::from_millis(100)))?; //! //! // Process each event. //! for event in events.iter() { //! // We can use the token we previously provided to `register` to //! // determine for which type the event is. //! match event.token() { //! SERVER => loop { //! // One or more connections are ready, so we'll attempt to //! // accept them (in a loop). //! match listener.accept() { //! Ok((connection, address)) => { //! println!("Got a connection from: {}", address); //! # drop(connection); //! }, //! // A "would block error" is returned if the operation //! // is not ready, so we'll stop trying to accept //! // connections. //! Err(ref err) if would_block(err) => break, //! Err(err) => return Err(err), //! } //! } //! # _ => unreachable!(), //! } //! } //! # return Ok(()); //! } //! //! fn would_block(err: &io::Error) -> bool { //! err.kind() == io::ErrorKind::WouldBlock //! } //! # } //! ``` }