Enum futures::future::MaybeDone

pub enum MaybeDone<Fut> where
    Fut: Future,  {
    Future(Fut),
    Done(<Fut as Future>::Output),
    Gone,
}

A future that may have completed.

This is created by the maybe_done() function.

Variants

Future(Fut)

A not-yet-completed future

Done(<Fut as Future>::Output)

The output of the completed future

Gone

The empty variant after the result of a MaybeDone has been taken using the take_output method.

Methods

impl<Fut> MaybeDone<Fut> where     Fut: Future,

pub fn output_mut(     self: Pin<&'a mut MaybeDone<Fut>> ) -> Option<&'a mut <Fut as Future>::Output>

Returns an Option containing a mutable reference to the output of the future. The output of this method will be Some if and only if the inner future has been completed and take_output has not yet been called.

pub fn take_output(     self: Pin<&mut MaybeDone<Fut>> ) -> Option<<Fut as Future>::Output>

Attempt to take the output of a MaybeDone without driving it towards completion.

Trait Implementations

impl<Fut> Unpin for MaybeDone<Fut> where     Fut: Unpin + Future,

impl<Fut> Debug for MaybeDone<Fut> where     Fut: Debug + Future,     <Fut as Future>::Output: Debug,

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

Formats the value using the given formatter.

impl<Fut> Future for MaybeDone<Fut> where     Fut: Future,

type Output = ()

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

The result of the Future.

fn poll(     self: Pin<&mut MaybeDone<Fut>>,     lw: &LocalWaker ) -> Poll<<MaybeDone<Fut> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

Attempt to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.

impl<Fut> FusedFuture for MaybeDone<Fut> where     Fut: Future,

fn is_terminated(&self) -> bool

Returns true if the underlying future should no longer be polled.