Struct futures::future::OptionFuture

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#[must_use = "futures do nothing unless you `.await` or poll them"]pub struct OptionFuture<F>(_);

[−] Expand description

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

Created by the From implementation for Option.

Examples

use futures::future::OptionFuture;

let mut a: OptionFuture<_> = Some(async { 123 }).into();
assert_eq!(a.await, Some(123));

a = None.into();
assert_eq!(a.await, None);

Trait Implementations

impl<F> Clone for OptionFuture<F> where
    F: Clone, [+]

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fn clone(&self) -> OptionFuture<F>[−]

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)[−]

Performs copy-assignment from source.

impl<F> Debug for OptionFuture<F> where
    F: Debug, [+]

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fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>[−]

Formats the value using the given formatter.

impl<T> From<Option<T>> for OptionFuture<T>[+]

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fn from(option: Option<T>) -> OptionFuture<T>[−]

Performs the conversion.

impl<F> FusedFuture for OptionFuture<F> where
    F: FusedFuture, [+]

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fn is_terminated(&self) -> bool[−]

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

impl<F> Future for OptionFuture<F> where
    F: Future, [+]

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type Output = Option<<F as Future>::Output>

The type of value produced on completion.

fn poll(
    self: Pin<&mut OptionFuture<F>>,
    cx: &mut Context<'_>
) -> Poll<<OptionFuture<F> as Future>::Output>[−]

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

impl<'pin, F> Unpin for OptionFuture<F> where
    __OptionFuture<'pin, F>: Unpin, 

impl<F> UnsafeUnpin for OptionFuture<F>