1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
use crate::io::util::read_line::read_line_internal;
use crate::io::AsyncBufRead;
use pin_project_lite::pin_project;
use std::io;
use std::mem;
use std::pin::Pin;
use std::task::{Context, Poll};
pin_project! {
#[derive(Debug)]
#[must_use = "streams do nothing unless polled"]
#[cfg_attr(docsrs, doc(cfg(feature = "io-util")))]
pub struct Lines<R> {
#[pin]
reader: R,
buf: String,
bytes: Vec<u8>,
read: usize,
}
}
pub(crate) fn lines<R>(reader: R) -> Lines<R>
where
R: AsyncBufRead,
{
Lines {
reader,
buf: String::new(),
bytes: Vec::new(),
read: 0,
}
}
impl<R> Lines<R>
where
R: AsyncBufRead + Unpin,
{
pub async fn next_line(&mut self) -> io::Result<Option<String>> {
use crate::future::poll_fn;
poll_fn(|cx| Pin::new(&mut *self).poll_next_line(cx)).await
}
pub fn get_mut(&mut self) -> &mut R {
&mut self.reader
}
pub fn get_ref(&mut self) -> &R {
&self.reader
}
pub fn into_inner(self) -> R {
self.reader
}
}
impl<R> Lines<R>
where
R: AsyncBufRead,
{
fn poll_next_line(
self: Pin<&mut Self>,
cx: &mut Context<'_>,
) -> Poll<io::Result<Option<String>>> {
let me = self.project();
let n = ready!(read_line_internal(me.reader, cx, me.buf, me.bytes, me.read))?;
debug_assert_eq!(*me.read, 0);
if n == 0 && me.buf.is_empty() {
return Poll::Ready(Ok(None));
}
if me.buf.ends_with('\n') {
me.buf.pop();
if me.buf.ends_with('\r') {
me.buf.pop();
}
}
Poll::Ready(Ok(Some(mem::replace(me.buf, String::new()))))
}
}
#[cfg(feature = "stream")]
impl<R: AsyncBufRead> crate::stream::Stream for Lines<R> {
type Item = io::Result<String>;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
Poll::Ready(match ready!(self.poll_next_line(cx)) {
Ok(Some(line)) => Some(Ok(line)),
Ok(None) => None,
Err(err) => Some(Err(err)),
})
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn assert_unpin() {
crate::is_unpin::<Lines<()>>();
}
}