forked from mirror/async-std
79 lines
2.3 KiB
Rust
79 lines
2.3 KiB
Rust
use std::mem;
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use std::pin::Pin;
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use std::str;
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use pin_project_lite::pin_project;
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use super::read_until_internal;
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use crate::io::{self, BufRead};
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use crate::stream::Stream;
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use crate::task::{Context, Poll};
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pin_project! {
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/// A stream of lines in a byte stream.
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///
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/// This stream is created by the [`lines`] method on types that implement [`BufRead`].
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///
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/// This type is an async version of [`std::io::Lines`].
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///
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/// [`lines`]: trait.BufRead.html#method.lines
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/// [`BufRead`]: trait.BufRead.html
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/// [`std::io::Lines`]: https://doc.rust-lang.org/std/io/struct.Lines.html
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#[derive(Debug)]
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pub struct Lines<R> {
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#[pin]
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pub(crate) reader: R,
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pub(crate) buf: String,
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pub(crate) bytes: Vec<u8>,
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pub(crate) read: usize,
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}
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}
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impl<R: BufRead> Stream for Lines<R> {
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type Item = io::Result<String>;
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fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
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let this = self.project();
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let n = futures_core::ready!(read_line_internal(
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this.reader,
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cx,
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this.buf,
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this.bytes,
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this.read
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))?;
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if n == 0 && this.buf.is_empty() {
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return Poll::Ready(None);
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}
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if this.buf.ends_with('\n') {
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this.buf.pop();
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if this.buf.ends_with('\r') {
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this.buf.pop();
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}
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}
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Poll::Ready(Some(Ok(mem::replace(this.buf, String::new()))))
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}
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}
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pub fn read_line_internal<R: BufRead + ?Sized>(
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reader: Pin<&mut R>,
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cx: &mut Context<'_>,
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buf: &mut String,
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bytes: &mut Vec<u8>,
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read: &mut usize,
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) -> Poll<io::Result<usize>> {
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let ret = futures_core::ready!(read_until_internal(reader, cx, b'\n', bytes, read));
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if str::from_utf8(&bytes).is_err() {
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Poll::Ready(ret.and_then(|_| {
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Err(io::Error::new(
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io::ErrorKind::InvalidData,
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"stream did not contain valid UTF-8",
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))
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}))
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} else {
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debug_assert!(buf.is_empty());
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debug_assert_eq!(*read, 0);
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// Safety: `bytes` is a valid UTF-8 because `str::from_utf8` returned `Ok`.
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mem::swap(unsafe { buf.as_mut_vec() }, bytes);
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Poll::Ready(ret)
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}
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}
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