Class: SizedQueue

Inherits:

Object

• Object
• SizedQueue

Defined in:

thread.c,
thread.c

Overview

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.

Instance Method Summary

• #clear ⇒ Object

  Removes all objects from the queue.

• #new(max) ⇒ Object constructor

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

• #max ⇒ Object

  Returns the maximum size of the queue.

• #max=(number) ⇒ Object

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

• #num_waiting ⇒ Object

  Returns the number of threads waiting on the queue.

• #pop ⇒ Object (also: #deq, #shift)

  Retrieves data from the queue.

• #push ⇒ Object (also: #enq, #<<)

  Pushes object to the queue.

Constructor Details

#new(max) ⇒ Object

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

# File 'thread.c', line 400

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;
}

Instance Method Details

#clear ⇒ Object

Removes all objects from the queue.

# File 'thread.c', line 521

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

#max ⇒ Object

Returns the maximum size of the queue.

# File 'thread.c', line 424

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

#max=(number) ⇒ Object

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

# File 'thread.c', line 437

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 ⇒ Object

Returns the number of threads waiting on the queue.

# File 'thread.c', line 535

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

#pop(non_block = false) ⇒ Object #deq(non_block = false) ⇒ Object #shift(non_block = false) ⇒ Object Also known as: deq, shift

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.

# File 'thread.c', line 508

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

#push(object) ⇒ Object #enq(object) ⇒ Object #<<(object) ⇒ Object Also known as: enq, <<

Pushes object to the queue.

If there is no space left in the queue, waits until space becomes available.

# File 'thread.c', line 468

static VALUE
rb_szqueue_push(VALUE self, VALUE obj)
{
    struct waiting_delete args;
    args.waiting = GET_SZQUEUE_WAITERS(self);
    args.th      = rb_thread_current();

    while (queue_length(self) >= GET_SZQUEUE_ULONGMAX(self)) {
	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, obj);
}