Struct tokio::io::Lines

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pub struct Lines<R> { /* private fields */ }
Expand description

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§

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impl<R> Lines<R>
where R: AsyncBufRead + Unpin,

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pub async fn next_line(&mut self) -> Result<Option<String>>

Returns the next line in the stream.

Cancel safety

This method is cancellation 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())
}
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pub fn get_mut(&mut self) -> &mut R

Obtains a mutable reference to the underlying reader.

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pub fn get_ref(&mut self) -> &R

Obtains a reference to the underlying reader.

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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.

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impl<R> Lines<R>
where R: AsyncBufRead,

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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::Pending if 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§

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impl<R: Debug> Debug for Lines<R>

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fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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impl<'__pin, R> Unpin for Lines<R>
where __Origin<'__pin, R>: Unpin,

Auto Trait Implementations§

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impl<R> RefUnwindSafe for Lines<R>
where R: RefUnwindSafe,

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impl<R> Send for Lines<R>
where R: Send,

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impl<R> Sync for Lines<R>
where R: Sync,

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impl<R> UnwindSafe for Lines<R>
where R: UnwindSafe,

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.