Struct lazy_init::LazyTransform
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pub struct LazyTransform<T, U> where
T: Sync,
U: Sync, { /* fields omitted */ }
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.
Methods
impl<T, U> LazyTransform<T, U> where
T: Sync,
U: Sync,
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T: Sync,
U: Sync,
fn new(t: T) -> LazyTransform<T, U>
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Construct a new, untransformed LazyTransform<T, U>
with an argument of
type T.
fn get_or_create<F>(&self, f: F) -> &U where
F: FnOnce(T) -> U,
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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!
fn get(&self) -> Option<&U>
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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>
.
fn into_inner(self) -> Result<U, T>
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Unwrap the contained value, returning Ok(U)
if the LazyTransform<T, U>
has been
transformed or Err(T)
if it has not.
Trait Implementations
impl<T, U> Sync for LazyTransform<T, U> where
T: Sync,
U: Sync,
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T: Sync,
U: Sync,
impl<T, U> Default for LazyTransform<T, U> where
T: Sync + Default,
U: Sync,
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T: Sync + Default,
U: Sync,