工作
Rust 的工作系統是採用輕量執行緒的形式。
一項工作具有一個頂層 Future,執行器會輪詢該 Future 來推動進度。該 Future 可能有一或多個巢狀 Future,供其 poll
方法輪詢,可約略對應至呼叫堆疊。藉由輪詢多個子項 Future (例如競爭的計時器和 I/O 作業),即可在工作內實現並行機制。
use tokio::io::{self, AsyncReadExt, AsyncWriteExt};
use tokio::net::TcpListener;
#[tokio::main]
async fn main() -> io::Result<()> {
let listener = TcpListener::bind("127.0.0.1:0").await?;
println!("listening on port {}", listener.local_addr()?.port());
loop {
let (mut socket, addr) = listener.accept().await?;
println!("connection from {addr:?}");
tokio::spawn(async move {
socket.write_all(b"Who are you?\n").await.expect("socket error");
let mut buf = vec![0; 1024];
let name_size = socket.read(&mut buf).await.expect("socket error");
let name = std::str::from_utf8(&buf[..name_size]).unwrap().trim();
let reply = format!("Thanks for dialing in, {name}!\n");
socket.write_all(reply.as_bytes()).await.expect("socket error");
});
}
}