Struct Lazy 

pub struct Lazy<V, F> { /* private fields */ }

A lazy-initialized view.

The view is only initialized when polled for a grant.

Implementations

impl<V, F> Lazy<V, F>

pub fn new(init: F) -> Self

Create a new lazy view.

pub fn into_inner(self) -> Option<V>

Return the inner type, if it has been initialized.

impl<V> Lazy<V, Box<dyn FnOnce() -> V>>

pub fn new_boxed(init: impl FnOnce() -> V + 'static) -> Self

Available on crate features std only.

Create a new lazy view with a boxed initialization function.

Trait Implementations

impl<V: Clone, F: Clone> Clone for Lazy<V, F>

fn clone(&self) -> Lazy<V, F>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<V: Debug, F: Debug> Debug for Lazy<V, F>

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

Formats the value using the given formatter.

impl<V: Hash, F: Hash> Hash for Lazy<V, F>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<V, F> View for Lazy<V, F>

where V: View, F: FnOnce() -> V,

type Item = <V as View>::Item

The streamed type.

type Error = <V as View>::Error

The error produced by poll_grant.

fn view(&self) -> &[Self::Item]

Obtain the current view of the stream.

fn poll_grant( self: Pin<&mut Self>, cx: &mut Context<'_>, count: usize, ) -> Poll<Result<(), Self::Error>>

Attempt to obtain a view of at least count elements.

fn release(&mut self, count: usize)

Attempt to advance past the first count elements in the current view.

fn grant(&mut self, count: usize) -> Grant<'_, Self>

Create a future that obtains a view of at least count elements.

fn blocking_grant(&mut self, count: usize) -> Result<(), Self::Error>

Obtains a view of at least count elements, blocking the current thread.

fn map_error<E, F>(self, f: F) -> MapError<Self, E, F>

where F: Fn(Self::Error) -> E,

Maps this view to a new view producing error E.

impl<V, F> ViewMut for Lazy<V, F>

where V: ViewMut, F: FnOnce() -> V,

fn view_mut(&mut self) -> &mut [Self::Item]

Obtain the current mutable view of the stream.

impl<V: Copy, F: Copy> Copy for Lazy<V, F>

impl<'pin, V, F> Unpin for Lazy<V, F>

where PinnedFieldsOf<__Lazy<'pin, V, F>>: Unpin,