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 T
pub fn get_or_init<F>(&self, f: F) -> &'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>
pub fn get_or_try_init<F, E>(&self, f: F) -> 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
.
Trait Implementations§
impl<'a, T: Sync> Sync for OnceRef<'a, T>
Auto Trait Implementations§
impl<'a, T> !Freeze for OnceRef<'a, T>
impl<'a, T> !RefUnwindSafe for OnceRef<'a, T>
impl<'a, T> Send for OnceRef<'a, T>where
T: Sync,
impl<'a, T> Unpin for OnceRef<'a, T>
impl<'a, T> UnwindSafe for OnceRef<'a, T>where
T: RefUnwindSafe,
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more