Crate cb_fut

Make a call to callback function without callback function.

This crate provide 2 macros to turn a call to function that require a callback parameter for return values into a function call that return a Future of that values.

These macro introduce an indirection layer to glue callback to Future thus it has some additional overhead.

Limitation

• If the callback is not intended to return a value, don’t use these two macros.
• If the function also return value, the returned value will be silently dropped.
• If the function take multiple callbacks to return value on different circumstance, don’t use these two macros.

What’s new in version 0.2.0

• once_blocked - which let user return value to function.
• stream_blocked - which let user return value to Stream.
• By default, it will use Rust standard channel. Now it also support Crossbeam-channel. To use this feature, add features=[“crossbeam”] to your cargo.toml. For example:

[dependencies]
cb_fut = {version = "^0.2", features = ["crossbeam"]}

Macros

once

Turn a function call that take a single callback function and return nothing into a function call without callback that return a future value.

once_blocked

Turn a function call that take a single callback function to return a value then wait for callback to return another value to continue it execution into a function that return a Future which resolve to a struct that is Deref into a result and it will automatically return value to a function when it is dropped.

stream

Turn a function call that take a single callback and return nothing into a function call without callback but return an implementation of futures::Stream called CBStream.

stream_blocked

Turn a function call that take a single callback and return nothing into a function call without callback but return an implementation of futures::Stream called CBStreamBlocked.

Structs

AlreadyReturnError

It mean that the value already return once and caller attempt to return something again.

CBBlockResult

A structure that act as handle to retrieve result as well as return a value to function.

CBStream

A represent of callback function arguments which implement futures::Stream trait.

CBStreamBlocked

An object that represent callback function arguments. It implement futures::Stream trait and return value to the function by using CBBlockResult.

Functions

channel

Utility function intended to be used internally. It will return a channel regarding to feature gate. The default is to use standard channel.