futures_util/io/
lines.rs

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

futures_util/io/
lines.rs
