class SizedQueue

This class represents queues of specified size capacity. The push operation may be blocked if the capacity is full.

See Queue for an example of how a SizedQueue works.

Public Class Methods

new(max) click to toggle source

Creates a fixed-length queue with a maximum size of max.

static VALUE
rb_szqueue_initialize(VALUE self, VALUE vmax)
{
    long max;

    max = NUM2LONG(vmax);
    if (max <= 0) {
        rb_raise(rb_eArgError, "queue size must be positive");
    }

    RSTRUCT_SET(self, QUEUE_QUE, ary_buf_new());
    RSTRUCT_SET(self, QUEUE_WAITERS, ary_buf_new());
    RSTRUCT_SET(self, SZQUEUE_WAITERS, ary_buf_new());
    RSTRUCT_SET(self, SZQUEUE_MAX, vmax);

    return self;
}

Public Instance Methods

<<(*args)

Alias for push.

Alias for: push

clear() click to toggle source

Removes all objects from the queue.

static VALUE
rb_szqueue_clear(VALUE self)
{
    rb_ary_clear(GET_QUEUE_QUE(self));
    wakeup_all_threads(GET_SZQUEUE_WAITERS(self));
    return self;
}

deq(*args)

Alias for pop.

Alias for: pop

enq(*args)

Alias for push.

Alias for: push

max() click to toggle source

Returns the maximum size of the queue.

static VALUE
rb_szqueue_max_get(VALUE self)
{
    return GET_SZQUEUE_MAX(self);
}

max=(number) click to toggle source

Sets the maximum size of the queue to the given number.

static VALUE
rb_szqueue_max_set(VALUE self, VALUE vmax)
{
    long max = NUM2LONG(vmax), diff = 0;
    VALUE t;

    if (max <= 0) {
        rb_raise(rb_eArgError, "queue size must be positive");
    }
    if ((unsigned long)max > GET_SZQUEUE_ULONGMAX(self)) {
        diff = max - GET_SZQUEUE_ULONGMAX(self);
    }
    RSTRUCT_SET(self, SZQUEUE_MAX, vmax);
    while (diff-- > 0 && !NIL_P(t = rb_ary_shift(GET_SZQUEUE_WAITERS(self)))) {
        rb_thread_wakeup_alive(t);
    }
    return vmax;
}

num_waiting() click to toggle source

Returns the number of threads waiting on the queue.

static VALUE
rb_szqueue_num_waiting(VALUE self)
{
    long len = queue_num_waiting(self);
    VALUE waiters = GET_SZQUEUE_WAITERS(self);
    len += RARRAY_LEN(waiters);
    return ULONG2NUM(len);
}

pop(non_block=false) click to toggle source

deq(non_block=false)

shift(non_block=false)

Retrieves data from the queue.

If the queue is empty, the calling thread is suspended until data is pushed onto the queue. If non_block is true, the thread isn't suspended, and an exception is raised.

static VALUE
rb_szqueue_pop(int argc, VALUE *argv, VALUE self)
{
    int should_block = queue_pop_should_block(argc, argv);
    return szqueue_do_pop(self, should_block);
}

Also aliased as: deq, shift

push(object, non_block=false) click to toggle source

enq(object, non_block=false)

<<(object)

Pushes object to the queue.

If there is no space left in the queue, waits until space becomes available, unless non_block is true. If non_block is true, the thread isn't suspended, and an exception is raised.

static VALUE
rb_szqueue_push(int argc, VALUE *argv, VALUE self)
{
    struct waiting_delete args;
    int should_block = szqueue_push_should_block(argc, argv);
    args.waiting = GET_SZQUEUE_WAITERS(self);
    args.th      = rb_thread_current();

    while (queue_length(self) >= GET_SZQUEUE_ULONGMAX(self)) {
        if (!should_block) {
            rb_raise(rb_eThreadError, "queue full");
        }
        rb_ary_push(args.waiting, args.th);
        rb_ensure((VALUE (*)())rb_thread_sleep_deadly, (VALUE)0, queue_delete_from_waiting, (VALUE)&args);
    }
    return queue_do_push(self, argv[0]);
}

Also aliased as: enq, <<

shift(*args)

Alias for pop.

Alias for: pop