1use super::read_line::read_line_internal;
2use futures_core::ready;
3use futures_core::stream::Stream;
4use futures_core::task::{Context, Poll};
5use futures_io::AsyncBufRead;
6use pin_project_lite::pin_project;
7use std::io;
8use std::mem;
9use std::pin::Pin;
10use std::string::String;
11use std::vec::Vec;
12
13pin_project! {
14 /// Stream for the [`lines`](super::AsyncBufReadExt::lines) method.
15 #[derive(Debug)]
16 #[must_use = "streams do nothing unless polled"]
17 pub struct Lines<R> {
18 #[pin]
19 reader: R,
20 buf: String,
21 bytes: Vec<u8>,
22 read: usize,
23 }
24}
25
26impl<R: AsyncBufRead> Lines<R> {
27 pub(super) fn new(reader: R) -> Self {
28 Self { reader, buf: String::new(), bytes: Vec::new(), read: 0 }
29 }
30}
31
32impl<R: AsyncBufRead> Stream for Lines<R> {
33 type Item = io::Result<String>;
34
35 fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
36 let this: Projection<'_, R> = self.project();
37 let n: usize = ready!(read_line_internal(this.reader, cx, this.buf, this.bytes, this.read))?;
38 *this.read = 0;
39 if n == 0 && this.buf.is_empty() {
40 return Poll::Ready(None);
41 }
42 if this.buf.ends_with('\n') {
43 this.buf.pop();
44 if this.buf.ends_with('\r') {
45 this.buf.pop();
46 }
47 }
48 Poll::Ready(Some(Ok(mem::take(dest:this.buf))))
49 }
50}
51