tcp_peek.rs - mozsearch

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#![warn(rust_2018_idioms)]

#![cfg(all(feature = "full", not(tokio_wasi)))] // Wasi doesn't support bind

use tokio::io::AsyncReadExt;

use tokio::net::TcpStream;

use tokio_test::assert_ok;

use std::thread;

use std::{io::Write, net};

#[tokio::test]

async fn peek() {

    let listener = net::TcpListener::bind("127.0.0.1:0").unwrap();

    let addr = listener.local_addr().unwrap();

    let t = thread::spawn(move || assert_ok!(listener.accept()).0);

    let left = net::TcpStream::connect(addr).unwrap();

    let mut right = t.join().unwrap();

    let _ = right.write(&[1, 2, 3, 4]).unwrap();

    let mut left: TcpStream = left.try_into().unwrap();

    let mut buf = [0u8; 16];

    let n = assert_ok!(left.peek(&mut buf).await);

    assert_eq!([1, 2, 3, 4], buf[..n]);

    let n = assert_ok!(left.read(&mut buf).await);

    assert_eq!([1, 2, 3, 4], buf[..n]);