Module future

Asynchronous values.

This module contains:

• The Future trait.

• The FutureExt 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 result, which constructs a future with an immediate defined value.

Structs

AndThen

Future for the and_then combinator, chaining a computation onto the end of another future which completes successfully.

CatchUnwind

Future for the catch_unwind combinator.

Empty

A future which is never resolved.

ErrInto

Future for the err_into combinator, changing the error type of a future.

Flatten

Future for the flatten combinator.

FlattenStream

Future for the flatten_stream combinator, flattening a future-of-a-stream to get just the result of the final stream as a stream.

Fuse

A future which “fuses” a future once it’s been resolved.

FutureOption

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

FutureResult

A future representing a value that is immediately ready.

Inspect

Do something with the item of a future, passing it on.

IntoStream

A type which converts a Future into a Stream containing a single element.

Join

Future for the join combinator, waiting for two futures to complete.

Join3

Future for the join3 combinator, waiting for three futures to complete.

Join4

Future for the join4 combinator, waiting for four futures to complete.

Join5

Future for the join5 combinator, waiting for five futures to complete.

JoinAll

A future which takes a list of futures and resolves with a vector of the completed values.

Lazy

A future which defers creation of the actual future until the future is polled.

LoopFn

A future implementing a tail-recursive loop.

Map

Future for the map combinator, changing the type of a future.

MapErr

Future for the map_err combinator, changing the error type of a future.

OrElse

Future for the or_else combinator, chaining a computation onto the end of a future which fails with an error.

PollFn

A future which adapts a function returning Poll.

Select

Future for the select combinator, waiting for one of two differently-typed futures to complete.

SelectAll

Future for the select_all combinator, waiting for one of any of a list of futures to complete.

SelectOk

Future for the select_ok combinator, waiting for one of any of a list of futures to successfully complete. Unlike select_all, this future ignores all but the last error, if there are any.

Shared

A future that is cloneable and can be polled in multiple threads. Use Future::shared() method to convert any future into a Shared future.

SharedError

A wrapped error of the original future that is cloneable and implements Deref for ease of use.

SharedItem

A wrapped item of the original future that is cloneable and implements Deref for ease of use.

Then

Future for the then combinator, chaining computations on the end of another future regardless of its outcome.

Enums

Either

The enum Either with variants Left and Right is a general purpose sum type with two cases.

Loop

An enum describing whether to break or continue a loop_fn loop.

Traits

Future

A future represents an asychronous computation that may fail.

FutureExt

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

IntoFuture

Types that can be converted into a future.

Functions

empty

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

err

Creates a new future that will immediately fail with the given error.

join_all

Creates a future which represents a collection of the results of the futures given.

lazy

Creates a new future which will eventually be the same as the one created by the closure provided.

loop_fn

Creates a new future implementing a tail-recursive loop.

ok

Creates a new future that will immediately resolve successfully to the given value.

poll_fn

Creates a new future wrapping around a function returning Poll.

result

Creates a new future that will immediate resolve with the given result.

select_all

Creates a new future which will select over a list of futures.

select_ok

Creates a new future which will select the first successful future over a list of futures.