Struct FutureReader

pub struct FutureReader<T> { /* private fields */ }
Expand description

Represents the readable end of a Component Model future.

Note that FutureReader instances must be disposed of using either read or close; otherwise the in-store representation will leak and the writer end will hang indefinitely. Consider using GuardedFutureReader to ensure that disposal happens automatically.

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impl<T> FutureReader<T>

pub async fn read(self, accessor: impl AsAccessor) -> Option<T>
where T: Lift + Send + 'static,

Read the value from this future.

The returned Future will yield Err if the guest has trapped before it could produce a result.

The [Accessor] provided can be acquired from Instance::run_concurrent or from within a host function for example.

§Panics

Panics if the store that the [Accessor] is derived from does not own this future.

pub async fn watch_writer(&mut self, accessor: impl AsAccessor)

Wait for the write end of this future to be dropped.

The [Accessor] provided can be acquired from Instance::run_concurrent or from within a host function for example.

§Panics

Panics if the store that the [Accessor] is derived from does not own this future.

pub fn into_val(self) -> Val

Convert this FutureReader into a Val.

pub fn from_val( store: impl AsContextMut, instance: Instance, value: &Val, ) -> Result<FutureReader<T>, Error>
where <impl AsContextMut as AsContext>::Data: Send,

Attempt to convert the specified Val to a FutureReader.

pub fn close(&mut self, store: impl AsContextMut)

Close this FutureReader, writing the default value.

§Panics

Panics if the store that the [Accessor] is derived from does not own this future. Usage of this future after calling close will also cause a panic.

pub fn close_with(&mut self, accessor: impl AsAccessor)

Convenience method around Self::close.

pub fn guard<A>(self, accessor: A) -> GuardedFutureReader<T, A>
where A: AsAccessor,

Returns a GuardedFutureReader which will auto-close this future on drop and clean it up from the store.

Note that the accessor provided must own this future and is additionally transferred to the GuardedFutureReader return value.

Trait Implementations§

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impl<T> Debug for FutureReader<T>

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

Formats the value using the given formatter. Read more
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impl<T, A> From<GuardedFutureReader<T, A>> for FutureReader<T>
where A: AsAccessor,

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fn from(guard: GuardedFutureReader<T, A>) -> FutureReader<T>

Converts to this type from the input type.
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impl<T> ComponentType for FutureReader<T>
where T: Send + Sync,

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impl<T> Lift for FutureReader<T>
where T: Send + Sync,

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impl<T> Lower for FutureReader<T>
where T: Send + Sync,

Auto Trait Implementations§

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impl<T> Freeze for FutureReader<T>

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impl<T> RefUnwindSafe for FutureReader<T>
where T: RefUnwindSafe,

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impl<T> Send for FutureReader<T>
where T: Send,

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impl<T> Sync for FutureReader<T>
where T: Sync,

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impl<T> Unpin for FutureReader<T>
where T: Unpin,

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impl<T> UnwindSafe for FutureReader<T>
where T: UnwindSafe,

Blanket Implementations§

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

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

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

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impl<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T> Pointable for T

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const ALIGN: usize

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> Pointee for T

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type Pointer = u32

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fn debug( pointer: <T as Pointee>::Pointer, f: &mut Formatter<'_>, ) -> Result<(), Error>

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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more