1 | use super::read_to_end::read_to_end_internal; |
2 | use futures_core::future::Future; |
3 | use futures_core::ready; |
4 | use futures_core::task::{Context, Poll}; |
5 | use futures_io::AsyncRead; |
6 | use std::pin::Pin; |
7 | use std::vec::Vec; |
8 | use std::{io, mem, str}; |
9 | |
10 | /// Future for the [`read_to_string`](super::AsyncReadExt::read_to_string) method. |
11 | #[derive (Debug)] |
12 | #[must_use = "futures do nothing unless you `.await` or poll them" ] |
13 | pub struct ReadToString<'a, R: ?Sized> { |
14 | reader: &'a mut R, |
15 | buf: &'a mut String, |
16 | bytes: Vec<u8>, |
17 | start_len: usize, |
18 | } |
19 | |
20 | impl<R: ?Sized + Unpin> Unpin for ReadToString<'_, R> {} |
21 | |
22 | impl<'a, R: AsyncRead + ?Sized + Unpin> ReadToString<'a, R> { |
23 | pub(super) fn new(reader: &'a mut R, buf: &'a mut String) -> Self { |
24 | let start_len: usize = buf.len(); |
25 | Self { reader, bytes: mem::take(dest:buf).into_bytes(), buf, start_len } |
26 | } |
27 | } |
28 | |
29 | fn read_to_string_internal<R: AsyncRead + ?Sized>( |
30 | reader: Pin<&mut R>, |
31 | cx: &mut Context<'_>, |
32 | buf: &mut String, |
33 | bytes: &mut Vec<u8>, |
34 | start_len: usize, |
35 | ) -> Poll<io::Result<usize>> { |
36 | let ret: Result = ready!(read_to_end_internal(reader, cx, bytes, start_len)); |
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 | // Safety: `bytes` is a valid UTF-8 because `str::from_utf8` returned `Ok`. |
44 | mem::swap(x:unsafe { buf.as_mut_vec() }, y:bytes); |
45 | Poll::Ready(ret) |
46 | } |
47 | } |
48 | |
49 | impl<A> Future for ReadToString<'_, A> |
50 | where |
51 | A: AsyncRead + ?Sized + Unpin, |
52 | { |
53 | type Output = io::Result<usize>; |
54 | |
55 | fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { |
56 | let Self { reader: &mut &mut A, buf: &mut &mut String, bytes: &mut Vec, start_len: &mut usize } = &mut *self; |
57 | read_to_string_internal(reader:Pin::new(pointer:reader), cx, buf, bytes, *start_len) |
58 | } |
59 | } |
60 | |