Struct Lazy

pub struct Lazy<T, F = fn() -> T> { /* private fields */ }

A cell which will be lazily initialized by the provided function the first time it is accessed.

This can be used as a safer alternative to static mut.

Implementations

impl<T, F> Lazy<T, F>

pub const fn new(initializer: F) -> Self

Returns a new Lazy cell, initialized with the provided initializer function.

pub fn get_if_present(&self) -> Option<&T>

Returns the value of the lazy cell, if it has already been initialized. Otherwise, returns None.

impl<T, F> Lazy<T, F>

where F: Fn() -> T,

pub fn get(&self) -> &T

Borrow the value, or initialize it if it has not yet been initialized.

pub fn get_mut(&mut self) -> &mut T

Borrow the value mutably, or initialize it if it has not yet been initialized.

pub fn init(&self)

Ensure that the cell has been initialized.

If the cell has yet to be initialized, this initializes it. If it is currently initializing, this spins until it has been fully initialized. Otherwise, this returns immediately.

Trait Implementations

impl<T, F> Debug for Lazy<T, F>

where T: Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T, F> Deref for Lazy<T, F>

where F: Fn() -> T,

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<T, F> DerefMut for Lazy<T, F>

where F: Fn() -> T,

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<T: Send, F: Send> Send for Lazy<T, F>

impl<T: Sync, F: Sync> Sync for Lazy<T, F>