Struct LazyTransform

pub struct LazyTransform<T, U> { /* private fields */ }

LazyTransform<T, U> is a synchronized holder type, that holds a value of type T until it is lazily converted into a value of type U.

Implementations

impl<T, U> LazyTransform<T, U>

pub fn new(t: T) -> LazyTransform<T, U>

Construct a new, untransformed LazyTransform<T, U> with an argument of type T.

pub fn into_inner(self) -> Result<U, T>

Unwrap the contained value, returning Ok(U) if the LazyTransform<T, U> has been transformed or Err(T) if it has not.

impl<T, U> LazyTransform<T, U>

pub fn get_or_create<F>(&self, f: F) -> &U

where F: FnOnce(T) -> U,

Get a reference to the transformed value, invoking f to transform it if the LazyTransform<T, U> has yet to be transformed. It is guaranteed that if multiple calls to get_or_create race, only one will invoke its closure, and every call will receive a reference to the newly transformed value.

The closure can only ever be called once, so think carefully about what transformation you want to apply!

pub fn get(&self) -> Option<&U>

Get a reference to the transformed value, returning Some(&U) if the LazyTransform<T, U> has been transformed or None if it has not. It is guaranteed that if a reference is returned it is to the transformed value inside the the LazyTransform<T>.

Trait Implementations

impl<T, U> Clone for LazyTransform<T, U>

where T: Clone, U: Clone,

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T, U> Default for LazyTransform<T, U>

where T: Default,

fn default() -> Self

Returns the “default value” for a type.

impl<T, U> Sync for LazyTransform<T, U>

where T: Send, U: Send + Sync,