pub struct OnceRef<'a, T> { /* private fields */ }
Expand description
A thread-safe cell which can be written to only once.
Implementations§
source§impl<'a, T> OnceRef<'a, T>
impl<'a, T> OnceRef<'a, T>
sourcepub fn set(&self, value: &'a T) -> Result<(), ()>
pub fn set(&self, value: &'a T) -> Result<(), ()>
Sets the contents of this cell to value
.
Returns Ok(())
if the cell was empty and Err(value)
if it was
full.
sourcepub fn get_or_init<F>(&self, f: F) -> &'a Twhere
F: FnOnce() -> &'a T,
pub fn get_or_init<F>(&self, f: F) -> &'a Twhere
F: FnOnce() -> &'a T,
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
.
sourcepub fn get_or_try_init<F, E>(&self, f: F) -> Result<&'a T, E>where
F: FnOnce() -> Result<&'a T, E>,
pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&'a T, E>where
F: FnOnce() -> Result<&'a T, E>,
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
.