Struct Counter 

pub struct Counter(/* private fields */);

A shared count with an asynchronous capacity notification.

Clones use the same count and capacity, but each clone registers its own waiting task.

Implementations

impl Counter

pub fn new(capacity: usize) -> Self

Creates a counter with the specified capacity.

pub fn get(&self) -> CounterGuard

Acquires one count and returns a guard that releases it on drop.

This does not wait for capacity; call available first when exceeding the configured capacity is not acceptable.

pub fn set_capacity(&self, cap: usize)

Changes the capacity and wakes waiting tasks.

pub fn is_available(&self) -> bool

Returns true if another count can be acquired without exceeding the capacity.

pub async fn available(&self)

Waits until the counter has free capacity.

Returns immediately if there is capacity available. Otherwise, registers the current task for wakeup and waits until a slot is freed.

pub async fn unavailable(&self)

Waits until the counter reaches its capacity (i.e., becomes unavailable).

pub fn total(&self) -> usize

Returns the number of currently held guards.

pub fn bind(&self, ctx: &BindCtx<'_>)

Subscribes ctx to capacity changes.

Services whose readiness depends on this counter must call this in Service::bind, otherwise their cached readiness is not invalidated when the counter fills or frees a slot.

Trait Implementations

impl Clone for Counter

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Counter

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

Formats the value using the given formatter.

impl Drop for Counter

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.