package moonpool

  1. Overview
  2. Docs

Module Moonpool.Bounded_queueSource

A blocking queue of finite size.

This queue, while still using locks underneath (like the regular blocking queue) should be enough for usage under reasonable contention.

The bounded size is helpful whenever some form of backpressure is desirable: if the queue is used to communicate between producer(s) and consumer(s), the consumer(s) can limit the rate at which producer(s) send new work down their way. Whenever the queue is full, means that producer(s) will have to wait before pushing new work.

  • since 0.4
Sourcetype 'a t

A bounded queue.

Sourceval create : max_size:int -> unit -> 'a t
Sourceval close : _ t -> unit

close q closes q. No new elements can be pushed into q, and after all the elements still in q currently are pop'd, pop will also raise Closed.

Sourceexception Closed
Sourceval push : 'a t -> 'a -> unit

push q x pushes x at the end of the queue. If q is full, this will block until there is room for x.

Sourceval try_push : force_lock:bool -> 'a t -> 'a -> bool

try_push q x attempts to push x into q, but abandons if it cannot acquire q or if q is full.

  • parameter force_lock

    if true, use Mutex.lock (which can block under contention); if false, use Mutex.try_lock, which might return false even if there's room in the queue.

Sourceval pop : 'a t -> 'a

pop q pops the first element off q. It blocks if q is empty, until some element becomes available.

  • raises Closed

    if q is empty and closed.

Sourceval try_pop : force_lock:bool -> 'a t -> 'a option

try_pop ~force_lock q tries to pop the first element, or returns None if no element is available or if it failed to acquire q.

  • parameter force_lock

    if true, use Mutex.lock (which can block under contention); if false, use Mutex.try_lock, which might return None even in presence of an element if there's contention.

  • raises Closed

    if q is empty and closed.

Sourceval size : _ t -> int

Number of elements currently in q

Sourceval max_size : _ t -> int

Maximum size of the queue. See create.

Sourceval transfer : 'a t -> 'a Queue.t -> unit

transfer bq q2 transfers all elements currently available in bq into local queue q2, and clears bq, atomically. It blocks if bq is empty.

See Bb_queue.transfer for more details.

  • raises Closed

    if bq is empty and closed.

Sourcetype 'a gen = unit -> 'a option
Sourcetype 'a iter = ('a -> unit) -> unit
Sourceval to_iter : 'a t -> 'a iter

to_iter q returns an iterator over all items in the queue. This might not terminate if q is never closed.

Sourceval to_gen : 'a t -> 'a gen

to_gen q returns a generator from the queue.

Sourceval to_seq : 'a t -> 'a Seq.t

to_gen q returns a (transient) sequence from the queue.