Struct diem_sdk::crypto::_once_cell::race::OnceBox [−]
pub struct OnceBox<T> { /* fields omitted */ }
Expand description
A thread-safe cell which can be written to only once.
Implementations
impl<T> OnceBox<T>
impl<T> OnceBox<T>
Sets the contents of this cell to value
.
Returns Ok(())
if the cell was empty and Err(value)
if it was
full.
pub fn get_or_init<F>(&self, f: F) -> &T where
F: FnOnce() -> Box<T, Global>,
pub fn get_or_init<F>(&self, f: F) -> &T where
F: FnOnce() -> Box<T, Global>,
Gets the contents of the cell, initializing it with f
if the cell was
empty.
If several threads concurrently run get_or_init
, more than one f
can
be called. However, all threads will return the same value, produced by
some f
.
Gets the contents of the cell, initializing it with f
if
the cell was empty. If the cell was empty and f
failed, an
error is returned.
If several threads concurrently run get_or_init
, more than one f
can
be called. However, all threads will return the same value, produced by
some f
.
Trait Implementations
Auto Trait Implementations
impl<T> RefUnwindSafe for OnceBox<T> where
T: RefUnwindSafe,
impl<T> UnwindSafe for OnceBox<T> where
T: UnwindSafe + RefUnwindSafe,
Blanket Implementations
Mutably borrows from an owned value. Read more
Instruments this type with the provided Span
, returning an
Instrumented
wrapper. Read more
pub fn vzip(self) -> V
Attaches the provided Subscriber
to this type, returning a
WithDispatch
wrapper. Read more
Attaches the current default Subscriber
to this type, returning a
WithDispatch
wrapper. Read more