Struct Lines
pub struct Lines<R> { /* private fields */ }
io-util only.Reads lines from an AsyncBufRead.
A Lines can be turned into a Stream with LinesStream.
This type is usually created using the lines method.
Implementations
impl<R> Lines<R>where R: AsyncBufRead + Unpin,
pub async fn next_line(&mut self) -> Result<Option<String>>
Returns the next line in the stream.
Cancel safety
This method is cancel safe.
Examples
use tokio::io::AsyncBufReadExt;
let mut lines = my_buf_read.lines();
while let Some(line) = lines.next_line().await? {
println!("length = {}", line.len())
}pub fn into_inner(self) -> R
Unwraps this Lines<R>, returning the underlying reader.
Note that any leftover data in the internal buffer is lost. Therefore, a following read from the underlying reader may lead to data loss.
impl<R> Lines<R>where R: AsyncBufRead,
pub fn poll_next_line( self: Pin<&mut Self>, cx: &mut Context<'_>, ) -> Poll<Result<Option<String>>>
Polls for the next line in the stream.
This method returns:
-
Poll::Pendingif the next line is not yet available. -
Poll::Ready(Ok(Some(line)))if the next line is available. -
Poll::Ready(Ok(None))if there are no more lines in this stream. -
Poll::Ready(Err(err))if an IO error occurred while reading the next line.
When the method returns Poll::Pending, the Waker in the provided Context is scheduled to receive a wakeup when more bytes become available on the underlying IO resource. Note that on multiple calls to poll_next_line, only the Waker from the Context passed to the most recent call is scheduled to receive a wakeup.
Trait Implementations
impl<'__pin, R> Unpin for Lines<R>where PinnedFieldsOf<__Origin<'__pin, R>>: Unpin,
Auto Trait Implementations
impl<R> Freeze for Lines<R>where R: Freeze,
impl<R> RefUnwindSafe for Lines<R>where R: RefUnwindSafe,
impl<R> Send for Lines<R>where R: Send,
impl<R> Sync for Lines<R>where R: Sync,
impl<R> UnsafeUnpin for Lines<R>where R: UnsafeUnpin,
impl<R> UnwindSafe for Lines<R>where R: UnwindSafe,
Blanket Implementations
impl<T> BorrowMut<T> for Twhere T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
impl<T> Instrument for T
fn instrument(self, span: Span) -> Instrumented<Self> ⓘ
fn in_current_span(self) -> Instrumented<Self> ⓘ
impl<T> WithSubscriber for T
fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self> ⓘ
fn with_current_subscriber(self) -> WithDispatch<Self> ⓘ
MIT License
Copyright © Tokio Contributors
https://docs.rs/tokio/1.53.1/tokio/io/struct.Lines.html