/* * 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; }