Struct async_unsync::semaphore::Semaphore

pub struct Semaphore { /* private fields */ }

An unsynchronized (!Sync), simple semaphore for asynchronous permit acquisition.

Implementations

impl Semaphore

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

Creates a new semaphore with the initial number of permits.

pub fn close(&self) -> usize

Closes the semaphore and returns the number of notified pending waiters.

This prevents the semaphore from issuing new permits and notifies all pending waiters.

pub fn is_closed(&self) -> bool

Returns true if the semaphore has been closed

pub fn waiters(&self) -> usize

Returns the number of currently registered Futures waiting for a Permit.

pub fn available_permits(&self) -> usize

Returns the current number of available permits.

pub fn outstanding_permits(&self) -> usize

Returns the current number of handed out permits.

pub fn add_permits(&self, n: usize)

Adds n new permits to the semaphore.

pub fn remove_permits(&self, n: usize)

Permanently reduces the number of available permits by n.

pub fn return_permits(&self, n: usize)

Returns n previously “forgotten” permits back to the semaphore.

This method complements Permit::forget and has no other uses.

pub fn try_acquire(&self) -> Result<Permit<'_>, TryAcquireError>

Acquires a single Permit or returns an error, if there are no available permits.

Errors

Fails, if the semaphore has been closed or has no available permits.

pub fn try_acquire_many(&self, n: usize) -> Result<Permit<'_>, TryAcquireError>

Acquires n Permits or returns an error, if there are not enough available permits.

Errors

Fails, if the semaphore has been closed or has not enough available permits.

pub fn acquire(&self) -> Acquire<'_>

Acquires a single Permit, potentially blocking until one becomes available.

Errors

Awaiting the Future fails, if the semaphore has been closed.

pub fn acquire_many(&self, n: usize) -> Acquire<'_>

Acquires n Permits, potentially blocking until they become available.

Errors

Awaiting the Future fails, if the semaphore has been closed.

Trait Implementations

impl Debug for Semaphore

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

Formats the value using the given formatter.