1 | use super::read_until::read_until_internal; |
2 | use futures_core::future::Future; |
3 | use futures_core::ready; |
4 | use futures_core::task::{Context, Poll}; |
5 | use futures_io::AsyncBufRead; |
6 | use std::io; |
7 | use std::mem; |
8 | use std::pin::Pin; |
9 | use std::str; |
10 | |
11 | /// Future for the [`read_line`](super::AsyncBufReadExt::read_line) method. |
12 | #[derive (Debug)] |
13 | #[must_use = "futures do nothing unless you `.await` or poll them" ] |
14 | pub struct ReadLine<'a, R: ?Sized> { |
15 | reader: &'a mut R, |
16 | buf: &'a mut String, |
17 | bytes: Vec<u8>, |
18 | read: usize, |
19 | } |
20 | |
21 | impl<R: ?Sized + Unpin> Unpin for ReadLine<'_, R> {} |
22 | |
23 | impl<'a, R: AsyncBufRead + ?Sized + Unpin> ReadLine<'a, R> { |
24 | pub(super) fn new(reader: &'a mut R, buf: &'a mut String) -> Self { |
25 | Self { reader, bytes: mem::take(dest:buf).into_bytes(), buf, read: 0 } |
26 | } |
27 | } |
28 | |
29 | pub(super) fn read_line_internal<R: AsyncBufRead + ?Sized>( |
30 | reader: Pin<&mut R>, |
31 | cx: &mut Context<'_>, |
32 | buf: &mut String, |
33 | bytes: &mut Vec<u8>, |
34 | read: &mut usize, |
35 | ) -> Poll<io::Result<usize>> { |
36 | let ret: Result = ready!(read_until_internal(reader, cx, b' \n' , bytes, read)); |
37 | if str::from_utf8(bytes).is_err() { |
38 | Poll::Ready(ret.and_then(|_| { |
39 | Err(io::Error::new(kind:io::ErrorKind::InvalidData, error:"stream did not contain valid UTF-8" )) |
40 | })) |
41 | } else { |
42 | debug_assert!(buf.is_empty()); |
43 | debug_assert_eq!(*read, 0); |
44 | // Safety: `bytes` is a valid UTF-8 because `str::from_utf8` returned `Ok`. |
45 | mem::swap(x:unsafe { buf.as_mut_vec() }, y:bytes); |
46 | Poll::Ready(ret) |
47 | } |
48 | } |
49 | |
50 | impl<R: AsyncBufRead + ?Sized + Unpin> Future for ReadLine<'_, R> { |
51 | type Output = io::Result<usize>; |
52 | |
53 | fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { |
54 | let Self { reader: &mut &mut R, buf: &mut &mut String, bytes: &mut Vec, read: &mut usize } = &mut *self; |
55 | read_line_internal(reader:Pin::new(pointer:reader), cx, buf, bytes, read) |
56 | } |
57 | } |
58 | |