Struct futures_util::stream::Filter

#[must_use = "streams do nothing unless polled"]
pub struct Filter<St, Fut, F> where
    St: Stream,
    F: FnMut(&St::Item) -> Fut,
    Fut: Future<Output = bool>,  { /* fields omitted */ }

A stream combinator used to filter the results of a stream and only yield some values.

This structure is produced by the Stream::filter method.

Methods

impl<St, Fut, F> Filter<St, Fut, F> where     St: Stream,     F: FnMut(&St::Item) -> Fut,     Fut: Future<Output = bool>,

Important traits for &'a mut W

impl<'a, W> Write for &'a mut W where
    W: Write + ?Sized, impl<'a, R> Read for &'a mut R where
    R: Read + ?Sized, impl<'a, I> Iterator for &'a mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

pub fn get_ref(&self) -> &St

Acquires a reference to the underlying stream that this combinator is pulling from.

Important traits for &'a mut W

impl<'a, W> Write for &'a mut W where
    W: Write + ?Sized, impl<'a, R> Read for &'a mut R where
    R: Read + ?Sized, impl<'a, I> Iterator for &'a mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

pub fn get_mut(&mut self) -> &mut St

Acquires a mutable reference to the underlying stream that this combinator is pulling from.

Note that care must be taken to avoid tampering with the state of the stream which may otherwise confuse this combinator.

pub fn into_inner(self) -> St

Consumes this combinator, returning the underlying stream.

Note that this may discard intermediate state of this combinator, so care should be taken to avoid losing resources when this is called.

Trait Implementations

impl<St: Debug, Fut: Debug, F: Debug> Debug for Filter<St, Fut, F> where     St: Stream,     F: FnMut(&St::Item) -> Fut,     Fut: Future<Output = bool>,     St::Item: Debug,

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

Formats the value using the given formatter.

impl<St, Fut, F> Unpin for Filter<St, Fut, F> where     St: Stream + Unpin,     F: FnMut(&St::Item) -> Fut,     Fut: Future<Output = bool> + Unpin,

impl<St, Fut, F> Stream for Filter<St, Fut, F> where     St: Stream,     F: FnMut(&St::Item) -> Fut,     Fut: Future<Output = bool>,

type Item = St::Item

Values yielded by the stream.

fn poll_next(self: PinMut<Self>, cx: &mut Context) -> Poll<Option<St::Item>>

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted.