Struct once_cell::race::OnceBox[][src]

pub struct OnceBox<T> { /* fields omitted */ }

A thread-safe cell which can be written to only once.

Implementations

impl<T> OnceBox<T>[src]

pub const fn new() -> OnceBox<T>[src]

Creates a new empty cell.

pub fn get(&self) -> Option<&T>[src]

Gets a reference to the underlying value.

pub fn set(&self, value: Box<T>) -> Result<(), Box<T>>[src]

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>, 
[src]

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.

pub fn get_or_try_init<F, E>(&self, f: F) -> Result<&T, E> where
    F: FnOnce() -> Result<Box<T>, E>, 
[src]

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<T: Debug> Debug for OnceBox<T>[src]

impl<T> Default for OnceBox<T>[src]

impl<T> Drop for OnceBox<T>[src]

impl<T: Sync + Send> Sync for OnceBox<T>[src]

Auto Trait Implementations

impl<T> RefUnwindSafe for OnceBox<T> where
    T: RefUnwindSafe

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

impl<T> Unpin for OnceBox<T>

impl<T> UnwindSafe for OnceBox<T> where
    T: RefUnwindSafe + UnwindSafe

Blanket Implementations

impl<T> Any for T where
    T: 'static + ?Sized
[src]

impl<T> Borrow<T> for T where
    T: ?Sized
[src]

impl<T> BorrowMut<T> for T where
    T: ?Sized
[src]

impl<T> From<T> for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 
[src]

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 
[src]

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 
[src]

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.