Trait futures_util::sink::SinkExt [] [src]

pub trait SinkExt: Sink {
    fn with<U, Fut, F>(self, f: F) -> With<Self, U, Fut, F>
    where
        F: FnMut(U) -> Fut,
        Fut: IntoFuture<Item = Self::SinkItem>,
        Fut::Error: From<Self::SinkError>,
        Self: Sized
, { ... }
fn with_flat_map<U, St, F>(self, f: F) -> WithFlatMap<Self, U, St, F>
    where
        F: FnMut(U) -> St,
        St: Stream<Item = Self::SinkItem, Error = Self::SinkError>,
        Self: Sized
, { ... }
fn sink_map_err<E, F>(self, f: F) -> SinkMapErr<Self, F>
    where
        F: FnOnce(Self::SinkError) -> E,
        Self: Sized
, { ... }
fn sink_err_into<E>(self) -> SinkErrInto<Self, E>
    where
        Self: Sized,
        Self::SinkError: Into<E>
, { ... }
fn buffer(self, amt: usize) -> Buffer<Self>
    where
        Self: Sized
, { ... }
fn fanout<S>(self, other: S) -> Fanout<Self, S>
    where
        Self: Sized,
        Self::SinkItem: Clone,
        S: Sink<SinkItem = Self::SinkItem, SinkError = Self::SinkError>
, { ... }
fn send(self, item: Self::SinkItem) -> Send<Self>
    where
        Self: Sized
, { ... }
fn send_all<S>(self, stream: S) -> SendAll<Self, S>
    where
        S: Stream<Item = Self::SinkItem>,
        Self::SinkError: From<S::Error>,
        Self: Sized
, { ... } }

An extension trait for Sinks that provides a variety of convenient combinator functions.

Provided Methods

Composes a function in front of the sink.

This adapter produces a new sink that passes each value through the given function f before sending it to self.

To process each value, f produces a future, which is then polled to completion before passing its result down to the underlying sink. If the future produces an error, that error is returned by the new sink.

Note that this function consumes the given sink, returning a wrapped version, much like Iterator::map.

Composes a function in front of the sink.

This adapter produces a new sink that passes each value through the given function f before sending it to self.

To process each value, f produces a stream, of which each value is passed to the underlying sink. A new value will not be accepted until the stream has been drained

Note that this function consumes the given sink, returning a wrapped version, much like Iterator::flat_map.

Examples


Using this function with an iterator through use of the stream::iter_ok() function

use futures::prelude::*;
use futures::stream;
use futures_channel::mpsc;
use futures_executor::block_on;

let (tx, rx) = mpsc::channel::<i32>(5);

let tx = tx.with_flat_map(|x| {
    stream::iter_ok(vec![42; x].into_iter().map(|y| y))
});

block_on(tx.send(5)).unwrap();
assert_eq!(block_on(rx.collect()), Ok(vec![42, 42, 42, 42, 42]));

Transforms the error returned by the sink.

Map this sink's error to a different error type using the Into trait.

If wanting to map errors of a Sink + Stream, use .sink_err_into().err_into().

Adds a fixed-size buffer to the current sink.

The resulting sink will buffer up to amt items when the underlying sink is unwilling to accept additional items. Calling flush on the buffered sink will attempt to both empty the buffer and complete processing on the underlying sink.

Note that this function consumes the given sink, returning a wrapped version, much like Iterator::map.

This method is only available when the std feature of this library is activated, and it is activated by default.

Fanout items to multiple sinks.

This adapter clones each incoming item and forwards it to both this as well as the other sink at the same time.

A future that completes after the given item has been fully processed into the sink, including flushing.

Note that, because of the flushing requirement, it is usually better to batch together items to send via send_all, rather than flushing between each item.

On completion, the sink is returned.

A future that completes after the given stream has been fully processed into the sink, including flushing.

This future will drive the stream to keep producing items until it is exhausted, sending each item to the sink. It will complete once both the stream is exhausted, the sink has received all items, and the sink has been flushed. Note that the sink is not closed.

Doing sink.send_all(stream) is roughly equivalent to stream.forward(sink). The returned future will exhaust all items from stream and send them to self.

On completion, the pair (sink, source) is returned.

Implementors