mirror of https://github.com/stjepang/smol
128 lines
3.7 KiB
Rust
128 lines
3.7 KiB
Rust
//! A small and fast async runtime.
|
|
//!
|
|
//! # Examples
|
|
//!
|
|
//! Connect to an HTTP website, make a GET request, and pipe the response to the standard output:
|
|
//!
|
|
//! ```
|
|
//! use smol::{io, net, prelude::*, Unblock};
|
|
//!
|
|
//! fn main() -> io::Result<()> {
|
|
//! smol::block_on(async {
|
|
//! let mut stream = net::TcpStream::connect("example.com:80").await?;
|
|
//! let req = b"GET / HTTP/1.1\r\nHost: example.com\r\nConnection: close\r\n\r\n";
|
|
//! stream.write_all(req).await?;
|
|
//!
|
|
//! let mut stdout = Unblock::new(std::io::stdout());
|
|
//! io::copy(&stream, &mut stdout).await?;
|
|
//! Ok(())
|
|
//! })
|
|
//! }
|
|
//! ```
|
|
//!
|
|
//! This example uses the [`net`] module for networking, but you can also use the primitive
|
|
//! [`Async`] type. See the [full code][get-request].
|
|
//!
|
|
//! Look inside the [examples] directory for more.
|
|
//!
|
|
//! [`async-net`]: https://docs.rs/async-net
|
|
//! [examples]: https://github.com/stjepang/smol/tree/master/examples
|
|
//! [get-request]: https://github.com/stjepang/smol/blob/master/examples/get-request.rs
|
|
|
|
#![forbid(unsafe_code)]
|
|
#![warn(missing_docs, missing_debug_implementations, rust_2018_idioms)]
|
|
|
|
#[cfg(doctest)]
|
|
doc_comment::doctest!("../README.md");
|
|
|
|
use std::future::Future;
|
|
use std::panic::catch_unwind;
|
|
use std::thread;
|
|
|
|
use once_cell::sync::Lazy;
|
|
|
|
#[doc(inline)]
|
|
pub use {
|
|
async_executor::{Executor, LocalExecutor, Task},
|
|
async_io::{block_on, Async, Timer},
|
|
blocking::{unblock, Unblock},
|
|
futures_lite::{future, io, stream},
|
|
futures_lite::{pin, ready},
|
|
};
|
|
|
|
#[doc(inline)]
|
|
pub use {
|
|
async_channel as channel, async_fs as fs, async_lock as lock, async_net as net,
|
|
async_process as process,
|
|
};
|
|
|
|
pub mod prelude {
|
|
//! Traits [`Future`], [`AsyncBufRead`], [`AsyncRead`], [`AsyncSeek`], [`AsyncWrite`], and
|
|
//! their extensions.
|
|
//!
|
|
//! # Examples
|
|
//!
|
|
//! ```
|
|
//! use smol::prelude::*;
|
|
//! ```
|
|
|
|
#[doc(no_inline)]
|
|
pub use futures_lite::{
|
|
future::{Future, FutureExt},
|
|
io::{AsyncBufRead, AsyncBufReadExt},
|
|
io::{AsyncRead, AsyncReadExt},
|
|
io::{AsyncSeek, AsyncSeekExt},
|
|
io::{AsyncWrite, AsyncWriteExt},
|
|
stream::{Stream, StreamExt},
|
|
};
|
|
}
|
|
|
|
/// Spawns a task onto the global executor (single-threaded by default).
|
|
///
|
|
/// There is a global executor that gets lazily initialized on first use. It is included in this
|
|
/// library for convenience when writing unit tests and small programs, but it is otherwise
|
|
/// more advisable to create your own [`Executor`].
|
|
///
|
|
/// By default, the global executor is run by a single background thread, but you can also
|
|
/// configure the number of threads by setting the `SMOL_THREADS` environment variable.
|
|
///
|
|
/// # Examples
|
|
///
|
|
/// ```
|
|
/// let task = smol::spawn(async {
|
|
/// 1 + 2
|
|
/// });
|
|
///
|
|
/// smol::block_on(async {
|
|
/// assert_eq!(task.await, 3);
|
|
/// });
|
|
/// ```
|
|
pub fn spawn<T: Send + 'static>(future: impl Future<Output = T> + Send + 'static) -> Task<T> {
|
|
static GLOBAL: Lazy<Executor> = Lazy::new(|| {
|
|
let num_threads = {
|
|
// Parse SMOL_THREADS or default to 1.
|
|
std::env::var("SMOL_THREADS")
|
|
.ok()
|
|
.and_then(|s| s.parse().ok())
|
|
.unwrap_or(1)
|
|
};
|
|
|
|
for n in 1..=num_threads {
|
|
thread::Builder::new()
|
|
.name(format!("smol-{}", n))
|
|
.spawn(|| {
|
|
loop {
|
|
let _ = catch_unwind(|| {
|
|
async_io::block_on(GLOBAL.run(future::pending::<()>()))
|
|
});
|
|
}
|
|
})
|
|
.expect("cannot spawn executor thread");
|
|
}
|
|
|
|
Executor::new()
|
|
});
|
|
|
|
GLOBAL.spawn(future)
|
|
}
|