Struct FutureAny 

pub struct FutureAny { /* private fields */ }

Represents a type-erased component model future.

This type is similar to ResourceAny where it’s a static guarantee that it represents a component model future, but it does not contain any information about the underlying type that is associated with this future. This is intended to be used in “dynamically typed” situations where embedders may not know ahead of time the type of a future being used by component that is loaded.

Closing futures

A FutureAny represents a resource that is owned by a Store. Proper disposal of a future requires invoking the FutureAny::close method to ensure that this handle does not leak. If FutureAny::close is not called then memory will not be leaked once the owning Store is dropped, but the resource handle will be leaked until the Store is dropped.

Note that special care should be taken when handling FutureAny in async functions. In this scenario an async host function can be cancelled (dropped) at any time and if a FutureAny it holds isn’t closed then the future will be leaked within the store until the store is dropped.

Cloning

Cloning a FutureAny does not duplicate the underlying future: all clones refer to the same read end, whose ownership can only be transferred once. After one clone has been lowered into a guest, piped, or closed, attempting any of those with another clone returns an error.

Implementations

impl FutureAny

pub fn try_into_future_reader<T>(self) -> Result<FutureReader<T>, Error>

where T: ComponentType + 'static,

Attempts to convert this FutureAny to a FutureReader<T> with a statically known type.

Errors

This function will return an error if T does not match the type of value on this future.

pub fn try_from_future_reader<T>( store: impl AsContextMut, reader: FutureReader<T>, ) -> Result<FutureAny, Error>

where T: ComponentType + 'static,

Attempts to convert reader to a FutureAny, erasing its statically known type.

Errors

This function will return an error if reader does not belong to store.

pub fn close(&mut self, store: impl AsContextMut) -> Result<(), Error>

Close this FutureAny.

This will close this future and cause any write that happens later to returned DROPPED.

Errors

Returns an error if this future has already been closed or otherwise transferred (e.g. lowered into a guest), or if it does not belong to store.

Trait Implementations

impl Clone for FutureAny

fn clone(&self) -> FutureAny

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl ComponentType for FutureAny

impl Debug for FutureAny

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

Formats the value using the given formatter.

impl From<FutureAny> for Val

fn from(i: FutureAny) -> Val

Converts to this type from the input type.

impl Lift for FutureAny

impl Lower for FutureAny

impl PartialEq for FutureAny

fn eq(&self, other: &FutureAny) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for FutureAny