Struct Reactive 

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

Available on crate feature std only.

A ReactiveRepr value with lock-free reads and a race-free typed change signal.

Reactive::get is a plain atomic load. Reactive::watch hands out a Changed whose Changed::changed awaits the next change and returns the new value. tokio’s watch handles the wakeup race, versioning, and multiple independent subscribers.

The value is held in the atomic (for lock-free reads) and carried on the watch (so changed() can return it without a separate read). set stores the atomic and then sends, which is a no-op when nobody is subscribed, so an idle value costs nothing beyond the atomic store.

Implementations

impl<T> Reactive<T>

where T: ReactiveRepr,

pub fn new(value: T) -> Reactive<T>

Available on crate features grpc and http only.

Create a new Reactive holding value.

pub fn get(&self) -> T

Available on crate features grpc and http only.

Read the current value (lock-free).

pub fn set(&self, value: T)

Available on crate features grpc and http only.

Store value and wake watchers.

pub fn watch(&self) -> Changed<T>

Available on crate features grpc and http only.

Subscribe to changes. Hold the returned Changed and loop Changed::changed to observe every change, its watch cursor is persistent, so no edge is missed (unlike re-subscribing per await).

Trait Implementations

impl<T> Debug for Reactive<T>

where T: Debug,

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

Formats the value using the given formatter.

impl<T> Default for Reactive<T>

where T: ReactiveRepr + Default,

fn default() -> Reactive<T>

Returns the “default value” for a type.