futures_util::task

Struct LocalFutureObj

pub struct LocalFutureObj<'a, T> { /* private fields */ }

Expand description

A custom trait object for polling futures, roughly akin to Box<dyn Future<Output = T> + 'a>.

This custom trait object was introduced as currently it is not possible to take dyn Trait by value and Box<dyn Trait> is not available in no_std contexts.

Implementations§

impl<'a, T> LocalFutureObj<'a, T>

pub fn new<F>(f: F) -> LocalFutureObj<'a, T> ⓘ
where F: UnsafeFutureObj<'a, T> + 'a,

Create a LocalFutureObj from a custom trait object representation.

pub unsafe fn into_future_obj(self) -> FutureObj<'a, T> ⓘ

Converts the LocalFutureObj into a FutureObj.

§Safety

To make this operation safe one has to ensure that the UnsafeFutureObj instance from which this LocalFutureObj was created actually implements Send.

Trait Implementations§

impl<T> Debug for LocalFutureObj<'_, T>

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

Formats the value using the given formatter. Read more

impl<T> Drop for LocalFutureObj<'_, T>

fn drop(&mut self)

Executes the destructor for this type. Read more

impl<'a, F> From<Box<F>> for LocalFutureObj<'a, ()>
where F: Future<Output = ()> + 'a,

fn from(boxed: Box<F>) -> LocalFutureObj<'a, ()> ⓘ

Converts to this type from the input type.

impl<'a> From<Box<dyn Future<Output = ()> + 'a>> for LocalFutureObj<'a, ()>

fn from(boxed: Box<dyn Future<Output = ()> + 'a>) -> LocalFutureObj<'a, ()> ⓘ

Converts to this type from the input type.

impl<'a, T> From<FutureObj<'a, T>> for LocalFutureObj<'a, T>

fn from(f: FutureObj<'a, T>) -> LocalFutureObj<'a, T> ⓘ

Converts to this type from the input type.

impl<'a, F> From<Pin<Box<F>>> for LocalFutureObj<'a, ()>
where F: Future<Output = ()> + 'a,

fn from(boxed: Pin<Box<F>>) -> LocalFutureObj<'a, ()> ⓘ

Converts to this type from the input type.

impl<'a> From<Pin<Box<dyn Future<Output = ()> + 'a>>> for LocalFutureObj<'a, ()>

fn from(boxed: Pin<Box<dyn Future<Output = ()> + 'a>>) -> LocalFutureObj<'a, ()> ⓘ

Converts to this type from the input type.

impl<T> Future for LocalFutureObj<'_, T>

type Output = T

The type of value produced on completion.

fn poll(self: Pin<&mut LocalFutureObj<'_, T>>, cx: &mut Context<'_>) -> Poll<T>

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

impl<T> Unpin for LocalFutureObj<'_, T>

Auto Trait Implementations§

impl<'a, T> Freeze for LocalFutureObj<'a, T>

impl<'a, T> !RefUnwindSafe for LocalFutureObj<'a, T>

impl<'a, T> !Send for LocalFutureObj<'a, T>

impl<'a, T> !Sync for LocalFutureObj<'a, T>

impl<'a, T> !UnwindSafe for LocalFutureObj<'a, T>

Blanket Implementations§

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

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

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

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

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

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

Mutably borrows from an owned value. Read more

impl<T> From<T> for T

fn from(t: T) -> T

Returns the argument unchanged.

impl<T> FutureExt for T
where T: Future + ?Sized,

fn map<U, F>(self, f: F) -> Map<Self, F> ⓘ
where F: FnOnce(Self::Output) -> U, Self: Sized,

Map this future’s output to a different type, returning a new future of the resulting type. Read more

fn map_into<U>(self) -> MapInto<Self, U> ⓘ
where Self::Output: Into<U>, Self: Sized,

Map this future’s output to a different type, returning a new future of the resulting type. Read more

fn then<Fut, F>(self, f: F) -> Then<Self, Fut, F> ⓘ
where F: FnOnce(Self::Output) -> Fut, Fut: Future, Self: Sized,

Chain on a computation for when a future finished, passing the result of the future to the provided closure f. Read more

fn left_future<B>(self) -> Either<Self, B> ⓘ
where B: Future<Output = Self::Output>, Self: Sized,

Wrap this future in an Either future, making it the left-hand variant of that Either. Read more

fn right_future<A>(self) -> Either<A, Self> ⓘ
where A: Future<Output = Self::Output>, Self: Sized,

Wrap this future in an Either future, making it the right-hand variant of that Either. Read more

fn into_stream(self) -> IntoStream<Self>
where Self: Sized,

Convert this future into a single element stream. Read more

fn flatten(self) -> Flatten<Self> ⓘ
where Self::Output: Future, Self: Sized,

Flatten the execution of this future when the output of this future is itself another future. Read more

fn flatten_stream(self) -> FlattenStream<Self>
where Self::Output: Stream, Self: Sized,

Flatten the execution of this future when the successful result of this future is a stream. Read more

fn fuse(self) -> Fuse<Self> ⓘ
where Self: Sized,

Fuse a future such that poll will never again be called once it has completed. This method can be used to turn any Future into a FusedFuture. Read more

fn inspect<F>(self, f: F) -> Inspect<Self, F> ⓘ
where F: FnOnce(&Self::Output), Self: Sized,

Do something with the output of a future before passing it on. Read more

fn catch_unwind(self) -> CatchUnwind<Self> ⓘ
where Self: Sized + UnwindSafe,

Catches unwinding panics while polling the future. Read more

fn shared(self) -> Shared<Self> ⓘ
where Self: Sized, Self::Output: Clone,

Create a cloneable handle to this future where all handles will resolve to the same result. Read more

fn remote_handle(self) -> (Remote<Self>, RemoteHandle<Self::Output>)
where Self: Sized,

Available on crate feature channel only.

Turn this future into a future that yields () on completion and sends its output to another future on a separate task. Read more

fn boxed<'a>(self) -> BoxFuture<'a, Self::Output>
where Self: Sized + Send + 'a,

Wrap the future in a Box, pinning it. Read more

fn boxed_local<'a>(self) -> LocalBoxFuture<'a, Self::Output>
where Self: Sized + 'a,

Wrap the future in a Box, pinning it. Read more

fn unit_error(self) -> UnitError<Self> ⓘ
where Self: Sized,

Turns a Future<Output = T> into a TryFuture<Ok = T, Error = ()>.

fn never_error(self) -> NeverError<Self> ⓘ
where Self: Sized,

Turns a Future<Output = T> into a TryFuture<Ok = T, Error = Never>.

fn poll_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Self::Output>
where Self: Unpin,

A convenience for calling Future::poll on Unpin future types.

fn now_or_never(self) -> Option<Self::Output>
where Self: Sized,

Evaluates and consumes the future, returning the resulting output if the future is ready after the first call to Future::poll. Read more

impl<T, U> Into<U> for T
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<F> IntoFuture for F
where F: Future,

type Output = <F as Future>::Output

The output that the future will produce on completion.

type IntoFuture = F

Which kind of future are we turning this into?

fn into_future(self) -> <F as IntoFuture>::IntoFuture

Creates a future from a value. Read more

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

type Error = Infallible

The type returned in the event of a conversion error.

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.

impl<F, T, E> TryFuture for F
where F: Future<Output = Result<T, E>> + ?Sized,

type Ok = T

The type of successful values yielded by this future

type Error = E

The type of failures yielded by this future

fn try_poll( self: Pin<&mut F>, cx: &mut Context<'_>, ) -> Poll<<F as Future>::Output>

Poll this TryFuture as if it were a Future. Read more

impl<Fut> TryFutureExt for Fut
where Fut: TryFuture + ?Sized,

fn flatten_sink<Item>(self) -> FlattenSink<Self, Self::Ok>
where Self::Ok: Sink<Item, Error = Self::Error>, Self: Sized,

Available on crate feature sink only.

Flattens the execution of this future when the successful result of this future is a Sink. Read more

fn map_ok<T, F>(self, f: F) -> MapOk<Self, F> ⓘ
where F: FnOnce(Self::Ok) -> T, Self: Sized,

Maps this future’s success value to a different value. Read more

fn map_ok_or_else<T, E, F>(self, e: E, f: F) -> MapOkOrElse<Self, F, E> ⓘ
where F: FnOnce(Self::Ok) -> T, E: FnOnce(Self::Error) -> T, Self: Sized,

Maps this future’s success value to a different value, and permits for error handling resulting in the same type. Read more

fn map_err<E, F>(self, f: F) -> MapErr<Self, F> ⓘ
where F: FnOnce(Self::Error) -> E, Self: Sized,

Maps this future’s error value to a different value. Read more

fn err_into<E>(self) -> ErrInto<Self, E> ⓘ
where Self: Sized, Self::Error: Into<E>,

Maps this future’s Error to a new error type using the Into trait. Read more

fn ok_into<U>(self) -> OkInto<Self, U> ⓘ
where Self: Sized, Self::Ok: Into<U>,

Maps this future’s Ok to a new type using the Into trait.

fn and_then<Fut, F>(self, f: F) -> AndThen<Self, Fut, F> ⓘ
where F: FnOnce(Self::Ok) -> Fut, Fut: TryFuture<Error = Self::Error>, Self: Sized,

Executes another future after this one resolves successfully. The success value is passed to a closure to create this subsequent future. Read more

fn or_else<Fut, F>(self, f: F) -> OrElse<Self, Fut, F> ⓘ
where F: FnOnce(Self::Error) -> Fut, Fut: TryFuture<Ok = Self::Ok>, Self: Sized,

Executes another future if this one resolves to an error. The error value is passed to a closure to create this subsequent future. Read more

fn inspect_ok<F>(self, f: F) -> InspectOk<Self, F> ⓘ
where F: FnOnce(&Self::Ok), Self: Sized,

Do something with the success value of a future before passing it on. Read more

fn inspect_err<F>(self, f: F) -> InspectErr<Self, F> ⓘ
where F: FnOnce(&Self::Error), Self: Sized,

Do something with the error value of a future before passing it on. Read more

fn try_flatten(self) -> TryFlatten<Self, Self::Ok> ⓘ
where Self::Ok: TryFuture<Error = Self::Error>, Self: Sized,

Flatten the execution of this future when the successful result of this future is another future. Read more

fn try_flatten_stream(self) -> TryFlattenStream<Self>
where Self::Ok: TryStream<Error = Self::Error>, Self: Sized,

Flatten the execution of this future when the successful result of this future is a stream. Read more

fn unwrap_or_else<F>(self, f: F) -> UnwrapOrElse<Self, F> ⓘ
where Self: Sized, F: FnOnce(Self::Error) -> Self::Ok,

Unwraps this future’s output, producing a future with this future’s Ok type as its Output type. Read more

fn into_future(self) -> IntoFuture<Self> ⓘ
where Self: Sized,

Wraps a TryFuture into a type that implements Future. Read more

fn try_poll_unpin( &mut self, cx: &mut Context<'_>, ) -> Poll<Result<Self::Ok, Self::Error>>
where Self: Unpin,

A convenience method for calling TryFuture::try_poll on Unpin future types.

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

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

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

Performs the conversion.

Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 24 bytes