Struct OnceBox

pub(crate) struct OnceBox<T> {
    ptr: Atomic<*mut T>,
}

Fields

ptr: Atomic<*mut T>

Implementations

impl<T> OnceBox<T>

pub const fn new() -> Self

pub unsafe fn get_unchecked(&self) -> Pin<&T>

Gets access to the value, assuming it is already initialized and this initialization has been observed by the current thread.

Since all modifications to the pointer have already been observed, the pointer load in this function can be performed with relaxed ordering, potentially allowing the optimizer to turn code like this:

once_box.get_or_init(|| Box::pin(42));
unsafe { once_box.get_unchecked() }

into

once_box.get_or_init(|| Box::pin(42))

Safety

This causes undefined behavior if the assumption above is violated.

pub fn get_or_init(&self, f: impl FnOnce() -> Pin<Box<T>>) -> Pin<&T>

pub fn take(&mut self) -> Option<Pin<Box<T>>>

fn initialize(&self, f: impl FnOnce() -> Pin<Box<T>>) -> Pin<&T>

Trait Implementations

impl<T> Drop for OnceBox<T>

fn drop(&mut self)

Executes the destructor for this type.

impl<T: Send> Send for OnceBox<T>

impl<T: Send + Sync> Sync for OnceBox<T>