Struct FuturesUnordered

#[must_use = "streams do nothing unless polled"]
pub struct FuturesUnordered<Fut> { /* private fields */ }

A set of futures which may complete in any order.

See FuturesOrdered for a version of this type that preserves a FIFO order.

This structure is optimized to manage a large number of futures. Futures managed by FuturesUnordered will only be polled when they generate wake-up notifications. This reduces the required amount of work needed to poll large numbers of futures.

FuturesUnordered can be filled by collecting an iterator of futures into a FuturesUnordered, or by pushing futures onto an existing FuturesUnordered. When new futures are added, poll_next must be called in order to begin receiving wake-ups for new futures.

Note that you can create a ready-made FuturesUnordered via the collect method, or you can start with an empty set with the FuturesUnordered::new constructor.

This type is only available when the std or alloc feature of this library is activated, and it is activated by default.

Implementations

impl<Fut> FuturesUnordered<Fut>

fn new() -> Self

Constructs a new, empty FuturesUnordered.

The returned FuturesUnordered does not contain any futures. In this state, FuturesUnordered::poll_next will return Poll::Ready(None).

fn len(&self) -> usize

Returns the number of futures contained in the set.

This represents the total number of in-flight futures.

fn is_empty(&self) -> bool

Returns true if the set contains no futures.

fn push(&self, future: Fut)

Push a future into the set.

This method adds the given future to the set. This method will not call poll on the submitted future. The caller must ensure that FuturesUnordered::poll_next is called in order to receive wake-up notifications for the given future.

fn iter(&self) -> Iter<'_, Fut>
where
    Fut: Unpin,

Returns an iterator that allows inspecting each future in the set.

fn iter_pin_ref(self: Pin<&Self>) -> IterPinRef<'_, Fut>

Returns an iterator that allows inspecting each future in the set.

fn iter_mut(&mut self) -> IterMut<'_, Fut>
where
    Fut: Unpin,

Returns an iterator that allows modifying each future in the set.

fn iter_pin_mut(self: Pin<&mut Self>) -> IterPinMut<'_, Fut>

Returns an iterator that allows modifying each future in the set.

impl<Fut> FuturesUnordered<Fut>

fn clear(&mut self)

Clears the set, removing all futures.

Trait Implementations

impl LocalSpawn for FuturesUnordered<LocalFutureObj<'_, ()>>

fn spawn_local_obj(&self, future_obj: LocalFutureObj<'static, ()>) -> Result<(), SpawnError>

impl Spawn for FuturesUnordered<FutureObj<'_, ()>>

fn spawn_obj(&self, future_obj: FutureObj<'static, ()>) -> Result<(), SpawnError>

impl<Fut> Debug for FuturesUnordered<Fut>

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

impl<Fut> Default for FuturesUnordered<Fut>

fn default() -> Self

impl<Fut> Drop for FuturesUnordered<Fut>

fn drop(&mut self)

impl<Fut> Extend<Fut> for FuturesUnordered<Fut>

fn extend<I>(&mut self, iter: I)
where
    I: IntoIterator<Item = Fut>,

impl<Fut> FromIterator<Fut> for FuturesUnordered<Fut>

fn from_iter<I>(iter: I) -> Self
where
    I: IntoIterator<Item = Fut>,

impl<Fut> Unpin for FuturesUnordered<Fut>

impl<Fut: Future> FusedStream for FuturesUnordered<Fut>

fn is_terminated(&self) -> bool

impl<Fut: Future> Stream for FuturesUnordered<Fut>

type Item = <Fut as Future>::Output;
fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>>
fn size_hint(&self) -> (usize, Option<usize>)

impl<Fut: Send + Sync> Sync for FuturesUnordered<Fut>

impl<Fut: Send> Send for FuturesUnordered<Fut>

impl<Fut: Unpin> IntoIterator for FuturesUnordered<Fut>

type Item = Fut;
type IntoIter = IntoIter<Fut>;
fn into_iter(self) -> Self::IntoIter

Auto Trait Implementations

impl<Fut> !Freeze for FuturesUnordered<Fut>

impl<Fut> !RefUnwindSafe for FuturesUnordered<Fut>

impl<Fut> !UnwindSafe for FuturesUnordered<Fut>

impl<Fut> UnsafeUnpin for FuturesUnordered<Fut> where Arc<ReadyToRunQueue<Fut>>: UnsafeUnpin, Atomic<*mut Task<Fut>>: UnsafeUnpin,

Blanket Implementations

impl<S> TryStreamExt for FuturesUnordered<Fut> where S: TryStream + ?Sized,

impl<S, T, E> TryStream for FuturesUnordered<Fut> where S: Stream<Item = Result<T, E>> + ?Sized,

type Ok = T;
type Error = E;
fn try_poll_next(self: Pin<&mut S>, cx: &mut Context<'_>) -> Poll<Option<Result<<S as TryStream>::Ok, <S as TryStream>::Error>>>

impl<Sp> LocalSpawnExt for FuturesUnordered<Fut> where Sp: LocalSpawn + ?Sized,

impl<Sp> SpawnExt for FuturesUnordered<Fut> where Sp: Spawn + ?Sized,

impl<T> Any for FuturesUnordered<Fut> where T: 'static + ?Sized,

fn type_id(&self) -> TypeId

impl<T> Borrow<T> for FuturesUnordered<Fut> where T: ?Sized,

fn borrow(&self) -> &T

impl<T> BorrowMut<T> for FuturesUnordered<Fut> where T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

impl<T> From<T> for FuturesUnordered<Fut>

fn from(t: T) -> T

Returns the argument unchanged.

impl<T> StreamExt for FuturesUnordered<Fut> where T: Stream + ?Sized,

impl<T, U> Into<U> for FuturesUnordered<Fut> where U: From<T>,

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of [From]<T> for U chooses to do.

impl<T, U> TryFrom<U> for FuturesUnordered<Fut> where U: Into<T>,

type Error = never;
fn try_from(value: U) -> Result<T, never>

impl<T, U> TryInto<U> for FuturesUnordered<Fut> where U: TryFrom<T>,

type Error = <U as TryFrom<T>>::Error;
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>