Struct PrioritySemaphore 

pub struct PrioritySemaphore { /* private fields */ }

A runtime-independent, priority-aware asynchronous semaphore.

Acquiring an immediately available permit is lock-free. Under contention, returned permits are reserved directly for the highest-priority waiter, so a newly arriving task cannot steal a wake-up.

Implementations

impl PrioritySemaphore

pub const MAX_PERMITS: usize = PERMIT_MASK

Largest supported initial permit count.

pub const fn new(permits: usize) -> Self

Creates a semaphore with permits concurrent permits.

Panics

Panics when permits is larger than PrioritySemaphore::MAX_PERMITS.

pub fn acquire(self: &Arc<Self>, priority: Priority) -> AcquireFuture

Acquires one permit at priority.

The returned future is cancellation-safe. If it is cancelled after a permit has already been assigned, that permit is immediately passed to the next waiter or returned to the semaphore.

pub fn try_acquire( self: &Arc<Self>, _priority: Priority, ) -> Result<Permit, TryAcquireError>

Attempts to acquire one immediately available permit.

This method never bypasses already queued waiters. priority is accepted for API symmetry, but only affects queued acquisitions.

pub fn close(&self)

Closes the semaphore and wakes every queued waiter.

Closing is idempotent. Permits acquired before the close remain valid, while all subsequent acquisition attempts fail.

pub fn available_permits(&self) -> usize

Returns the number of permits that can be acquired immediately.

pub fn queued(&self) -> usize

Returns the number of futures currently waiting in the priority queue.

pub fn is_closed(&self) -> bool

Returns true after PrioritySemaphore::close has been called.

Trait Implementations

impl Debug for PrioritySemaphore

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

Formats the value using the given formatter.