Module future

Asynchronous values.

This module contains:

• The Future trait.
• The FutureExt and TryFutureExt trait, which provides adapters for chaining and composing futures.
• Top-level future combinators like lazy which creates a future from a closure that defines its return value, and ready, which constructs a future with an immediate defined value.

Re-exports

pub use core::future::Future;

Structs

AlwaysReady

Future for the always_ready function.

AndThen

Future for the and_then method.

ErrInto

Future for the err_into method.

Flatten

Future for the flatten method.

FlattenSink

Sink for the flatten_sink method.

FlattenStream

Stream for the flatten_stream method.

Fuse

Future for the fuse method.

FutureObj

A custom trait object for polling futures, roughly akin to Box<dyn Future<Output = T> + Send + 'a>.

Inspect

Future for the inspect method.

InspectErr

Future for the inspect_err method.

InspectOk

Future for the inspect_ok method.

IntoFuture

Future for the into_future method.

IntoStream

Stream for the into_stream method.

Join

Future for the join function.

Join3

Future for the join3 function.

Join4

Future for the join4 function.

Join5

Future for the join5 function.

Lazy

Future for the lazy function.

LocalFutureObj

A custom trait object for polling futures, roughly akin to Box<dyn Future<Output = T> + 'a>.

Map

Future for the map method.

MapErr

Future for the map_err method.

MapInto

Future for the map_into combinator.

MapOk

Future for the map_ok method.

MapOkOrElse

Future for the map_ok_or_else method.

NeverError

Future for the never_error combinator.

OkInto

Future for the ok_into method.

OptionFuture

A future representing a value which may or may not be present.

OrElse

Future for the or_else method.

Pending

Future for the pending() function.

PollFn

Future for the poll_fn function.

PollImmediate

Future for the poll_immediate function.

Ready

Future for the ready function.

Select

Future for the select() function.

Then

Future for the then method.

TryFlatten

Future for the try_flatten method.

TryFlattenStream

Future for the try_flatten_stream method.

TryJoin

Future for the try_join function.

TryJoin3

Future for the try_join3 function.

TryJoin4

Future for the try_join4 function.

TryJoin5

Future for the try_join5 function.

TrySelect

Future for the try_select() function.

UnitError

Future for the unit_error combinator.

UnwrapOrElse

Future for the unwrap_or_else method.

Enums

Either

Combines two different futures, streams, or sinks having the same associated types into a single type.

MaybeDone

A future that may have completed.

TryMaybeDone

A future that may have completed with an error.

Traits

FusedFuture

A future which tracks whether or not the underlying future should no longer be polled.

FutureExt

An extension trait for Futures that provides a variety of convenient adapters.

TryFuture

A convenience for futures that return Result values that includes a variety of adapters tailored to such futures.

TryFutureExt

Adapters specific to Result-returning futures

UnsafeFutureObj

A custom implementation of a future trait object for FutureObj, providing a vtable with drop support.

Functions

always_ready

Creates a future that is always immediately ready with a value.

err

Create a future that is immediately ready with an error value.

join

Joins the result of two futures, waiting for them both to complete.

join3

Same as join, but with more futures.

join4

Same as join, but with more futures.

join5

Same as join, but with more futures.

lazy

Creates a new future that allows delayed execution of a closure.

maybe_done

Wraps a future into a MaybeDone

ok

Create a future that is immediately ready with a success value.

pending

Creates a future which never resolves, representing a computation that never finishes.

poll_fn

Creates a new future wrapping around a function returning Poll.

poll_immediate

Creates a future that is immediately ready with an Option of a value. Specifically this means that poll always returns Poll::Ready.

ready

Creates a future that is immediately ready with a value.

select

Waits for either one of two differently-typed futures to complete.

try_join

Joins the result of two futures, waiting for them both to complete or for one to produce an error.

try_join3

Same as try_join, but with more futures.

try_join4

Same as try_join, but with more futures.

try_join5

Same as try_join, but with more futures.

try_maybe_done

Wraps a future into a TryMaybeDone

try_select

Waits for either one of two differently-typed futures to complete.