async-std/src/io/buf_read/split.rs
Yoshua Wuyts e1deaa58d8 Add BufRead::split (#312)
* add BufRead::split

Signed-off-by: Yoshua Wuyts <yoshuawuyts@gmail.com>

* fix docs

Signed-off-by: Yoshua Wuyts <yoshuawuyts@gmail.com>

* Update src/io/buf_read/mod.rs

Co-Authored-By: Stjepan Glavina <stjepang@gmail.com>
2019-10-14 15:49:54 +02:00

46 lines
1.4 KiB
Rust

use std::mem;
use std::pin::Pin;
use super::read_until_internal;
use crate::io::{self, BufRead};
use crate::stream::Stream;
use crate::task::{Context, Poll};
/// A stream over the contents of an instance of [`BufRead`] split on a particular byte.
///
/// This stream is created by the [`split`] method on types that implement [`BufRead`].
///
/// This type is an async version of [`std::io::Split`].
///
/// [`split`]: trait.BufRead.html#method.lines
/// [`BufRead`]: trait.BufRead.html
/// [`std::io::Split`]: https://doc.rust-lang.org/std/io/struct.Split.html
#[derive(Debug)]
pub struct Split<R> {
pub(crate) reader: R,
pub(crate) buf: Vec<u8>,
pub(crate) read: usize,
pub(crate) delim: u8,
}
impl<R: BufRead> Stream for Split<R> {
type Item = io::Result<Vec<u8>>;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
let Self {
reader,
buf,
read,
delim,
} = unsafe { self.get_unchecked_mut() };
let reader = unsafe { Pin::new_unchecked(reader) };
let n = futures_core::ready!(read_until_internal(reader, cx, *delim, buf, read))?;
if n == 0 && buf.is_empty() {
return Poll::Ready(None);
}
if buf[buf.len() - 1] == *delim {
buf.pop();
}
Poll::Ready(Some(Ok(mem::replace(buf, vec![]))))
}
}