/*
* Document-method: pop
* call_seq: pop(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_queue_pop(int argc, VALUE *argv, VALUE self)
{
Queue *queue;
int should_block;
VALUE result;
Data_Get_Struct(self, Queue, queue);
if (argc == 0) {
should_block = 1;
} else if (argc == 1) {
should_block = !RTEST(argv[0]);
} else {
rb_raise(rb_eArgError, "wrong number of arguments (%d for 1)", argc);
}
lock_mutex(&queue->mutex);
if (!queue->values.entries && !should_block) {
unlock_mutex(&queue->mutex);
rb_raise(private_eThreadError, "queue empty");
}
while (!queue->values.entries) {
wait_condvar(&queue->value_available, &queue->mutex);
}
result = shift_list(&queue->values);
if (queue->capacity && queue->values.size < queue->capacity) {
signal_condvar(&queue->space_available);
}
unlock_mutex(&queue->mutex);
return result;
}