Struct ResettableOnceLock 

pub struct ResettableOnceLock<T> { /* private fields */ }

ResettableOnceLock provides thread-safe access to a value of type T via a specific state machine.

• Fresh values of the lock start in a “to be updated” state.
• When values are in “to be updated” then calls to get will return None.
• In the to be updated state, the first call to get_or_update will run update on the object stored in the lock and transition the lock to the “updated” state.
• Once in the updated state, calls to get will return a reference to the shared object, future calls to get_or_update will behave just like a call to get in this way.
• A call to reset will transition the lock back to the “to be updated” state. Crucially, this requires mutable access to the lock object, making the patterns expressable via this lock less expressive than a regular mutex.

Implementations

impl<T> ResettableOnceLock<T>

pub fn new(elt: T) -> ResettableOnceLock<T>

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

pub fn get_or_update(&self, update: impl FnOnce(&mut T)) -> &T

pub fn reset(&mut self)

Reset the state of the lock to gate further accesses to the underlying value on another call to get_or_update.

Trait Implementations

impl<T: Send> Send for ResettableOnceLock<T>

impl<T: Send> Sync for ResettableOnceLock<T>