| use super::read_to_end::read_to_end_internal; |
| use futures_core::future::Future; |
| use futures_core::ready; |
| use futures_core::task::{Context, Poll}; |
| use futures_io::AsyncRead; |
| use std::pin::Pin; |
| use std::vec::Vec; |
| use std::{io, mem, str}; |
| |
| /// Future for the [`read_to_string`](super::AsyncReadExt::read_to_string) method. |
| #[derive(Debug)] |
| #[must_use = "futures do nothing unless you `.await` or poll them"] |
| pub struct ReadToString<'a, R: ?Sized> { |
| reader: &'a mut R, |
| buf: &'a mut String, |
| bytes: Vec<u8>, |
| start_len: usize, |
| } |
| |
| impl<R: ?Sized + Unpin> Unpin for ReadToString<'_, R> {} |
| |
| impl<'a, R: AsyncRead + ?Sized + Unpin> ReadToString<'a, R> { |
| pub(super) fn new(reader: &'a mut R, buf: &'a mut String) -> Self { |
| let start_len = buf.len(); |
| Self { reader, bytes: mem::take(buf).into_bytes(), buf, start_len } |
| } |
| } |
| |
| fn read_to_string_internal<R: AsyncRead + ?Sized>( |
| reader: Pin<&mut R>, |
| cx: &mut Context<'_>, |
| buf: &mut String, |
| bytes: &mut Vec<u8>, |
| start_len: usize, |
| ) -> Poll<io::Result<usize>> { |
| let ret = ready!(read_to_end_internal(reader, cx, bytes, start_len)); |
| if str::from_utf8(bytes).is_err() { |
| Poll::Ready(ret.and_then(|_| { |
| Err(io::Error::new(io::ErrorKind::InvalidData, "stream did not contain valid UTF-8")) |
| })) |
| } else { |
| debug_assert!(buf.is_empty()); |
| // Safety: `bytes` is a valid UTF-8 because `str::from_utf8` returned `Ok`. |
| mem::swap(unsafe { buf.as_mut_vec() }, bytes); |
| Poll::Ready(ret) |
| } |
| } |
| |
| impl<A> Future for ReadToString<'_, A> |
| where |
| A: AsyncRead + ?Sized + Unpin, |
| { |
| type Output = io::Result<usize>; |
| |
| fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { |
| let Self { reader, buf, bytes, start_len } = &mut *self; |
| read_to_string_internal(Pin::new(reader), cx, buf, bytes, *start_len) |
| } |
| } |