diff options
author | Taiki Endo <te316e89@gmail.com> | 2019-07-15 15:23:42 +0900 |
---|---|---|
committer | Sean McArthur <sean@seanmonstar.com> | 2019-07-15 11:52:13 -0700 |
commit | ab040bb498c96623f413efdc9fc16c46f72f9c63 (patch) | |
tree | d9ec2e165ee4968502f0b85b279b441531cdfa25 /tokio/src/io | |
parent | 0cfa120ba8c93822d6a84f2e7392008d84622010 (diff) |
tokio: add AsyncBufReadExt::read_line
Diffstat (limited to 'tokio/src/io')
-rw-r--r-- | tokio/src/io/async_buf_read_ext.rs | 37 | ||||
-rw-r--r-- | tokio/src/io/mod.rs | 1 | ||||
-rw-r--r-- | tokio/src/io/read_line.rs | 70 |
3 files changed, 108 insertions, 0 deletions
diff --git a/tokio/src/io/async_buf_read_ext.rs b/tokio/src/io/async_buf_read_ext.rs index 8cbfec45..e8178074 100644 --- a/tokio/src/io/async_buf_read_ext.rs +++ b/tokio/src/io/async_buf_read_ext.rs @@ -1,3 +1,4 @@ +use crate::io::read_line::{read_line, ReadLine}; use crate::io::read_until::{read_until, ReadUntil}; use tokio_io::AsyncBufRead; @@ -29,6 +30,42 @@ pub trait AsyncBufReadExt: AsyncBufRead { { read_until(self, byte, buf) } + + /// Creates a future which will read all the bytes associated with this I/O + /// object into `buf` until a newline (the 0xA byte) or EOF is reached, + /// This method is the async equivalent to [`BufRead::read_line`](std::io::BufRead::read_line). + /// + /// This function will read bytes from the underlying stream until the + /// newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes + /// up to, and including, the delimiter (if found) will be appended to + /// `buf`. + /// + /// The returned future will resolve to the number of bytes read once the read + /// operation is completed. + /// + /// In the case of an error the buffer and the object will be discarded, with + /// the error yielded. + /// + /// # Errors + /// + /// This function has the same error semantics as [`read_until`] and will + /// also return an error if the read bytes are not valid UTF-8. If an I/O + /// error is encountered then `buf` may contain some bytes already read in + /// the event that all data read so far was valid UTF-8. + /// + /// [`read_until`]: AsyncBufReadExt::read_until + /// + /// # Examples + /// + /// ``` + /// unimplemented!(); + /// ``` + fn read_line<'a>(&'a mut self, buf: &'a mut String) -> ReadLine<'a, Self> + where + Self: Unpin, + { + read_line(self, buf) + } } impl<R: AsyncBufRead + ?Sized> AsyncBufReadExt for R {} diff --git a/tokio/src/io/mod.rs b/tokio/src/io/mod.rs index b185701a..bd1440ee 100644 --- a/tokio/src/io/mod.rs +++ b/tokio/src/io/mod.rs @@ -42,6 +42,7 @@ mod async_write_ext; mod copy; mod read; mod read_exact; +mod read_line; mod read_to_end; mod read_until; mod write; diff --git a/tokio/src/io/read_line.rs b/tokio/src/io/read_line.rs new file mode 100644 index 00000000..987830d9 --- /dev/null +++ b/tokio/src/io/read_line.rs @@ -0,0 +1,70 @@ +use super::read_until::read_until_internal; +use std::future::Future; +use std::io; +use std::mem; +use std::pin::Pin; +use std::str; +use std::task::{Context, Poll}; +use tokio_io::AsyncBufRead; + +/// Future for the [`read_line`](crate::io::AsyncBufReadExt::read_line) method. +#[derive(Debug)] +#[must_use = "futures do nothing unless you `.await` or poll them"] +pub struct ReadLine<'a, R: ?Sized + Unpin> { + reader: &'a mut R, + buf: &'a mut String, + bytes: Vec<u8>, + read: usize, +} + +impl<R: ?Sized + Unpin> Unpin for ReadLine<'_, R> {} + +pub(crate) fn read_line<'a, R>(reader: &'a mut R, buf: &'a mut String) -> ReadLine<'a, R> +where + R: AsyncBufRead + ?Sized + Unpin, +{ + ReadLine { + reader, + bytes: unsafe { mem::replace(buf.as_mut_vec(), Vec::new()) }, + buf, + read: 0, + } +} + +pub(super) fn read_line_internal<R: AsyncBufRead + ?Sized>( + reader: Pin<&mut R>, + cx: &mut Context<'_>, + buf: &mut String, + bytes: &mut Vec<u8>, + read: &mut usize, +) -> Poll<io::Result<usize>> { + let ret = ready!(read_until_internal(reader, cx, b'\n', bytes, read)); + 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()); + debug_assert_eq!(*read, 0); + // 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<R: AsyncBufRead + ?Sized + Unpin> Future for ReadLine<'_, R> { + type Output = io::Result<usize>; + + fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> { + let Self { + reader, + buf, + bytes, + read, + } = &mut *self; + read_line_internal(Pin::new(reader), cx, buf, bytes, read) + } +} |