early stages of a php libevent project (inspired by reactphp/react)

EventLoop.php

<?php

include('EventTrait.php');

class EventLoop
{
    use EventTrait;

    private $base;
    private $events;
    private $deleted;

    public function __construct(){   
        $this->base = event_base_new();
        $this->deleted = new SplQueue();
        $this->iteratorMode = SplDoublyLinkedList::IT_MODE_FIFO | SplDoublyLinkedList::IT_MODE_DELETE;
        $this->deleted->setIteratorMode($this->iteratorMode);
    }

    public function setTimeout(callable $callback, $seconds){
        $this->setTimer($callback, $seconds);
    }

    public function setInterval(callable $callback, $seconds){
        $this->setTimer($callback, $seconds, true);
    }

    protected function setTimer($callback,$seconds,$persist = false){
        $event = $this->createEvent();   
        $event->callback = $callback;
        $event->seconds = $seconds;
        $event->persist = $persist;

        $cb = function() use ($event) {
            call_user_func($event->callback);
            if($event->persist){
                $this->dispatchEvent($event);
            }
            else{
                event_del($event->resource);
                $this->deleted->enqueue($event->hash);
            }
        };

        event_timer_set($event->resource, $cb);
        event_base_set($event->resource, $this->base);
        $this->dispatchEvent($event);
    }

    protected function dispatchEvent($event){
        $seconds = isset($event->seconds) ? abs($event->seconds) * 1000000 : -1;
        event_add($event->resource,$seconds);
    }

    protected function createEvent(){

        if(count($this->deleted) > 0){
            $deleted = $this->deleted->dequeue();
            event_free($this->events[$deleted]->resource);
            unset($this->events[$deleted]);
        }

        $hash = spl_object_hash($event = new stdClass());

        $event->resource = event_new();
        $event->hash = $hash;

        $this->events[$hash] = $event;
        return $event;
    }

    public function run(){
        event_base_loop($this->base);
    }

    public function stop(){
        event_base_loopexit($this->base);
    }

}

EventTrait.php

<?php

trait EventTrait
{
    private $observers;
    private $once;
    private $iteratorMode;

    public function __construct(){   
        $this->once = array();   
    }

    public function on($eventName, $callback) {
        $this->observers[$eventName][] = function($arguments) use ($callback) {
            return function() use($callback,$arguments){
                call_user_func($callback,$arguments);
            };
        };
    }

    public function emit($eventName,$arguments = array()){
        if(!empty($this->observers[$eventName])){
            foreach($this->observers[$eventName] as $func){
                $this->setTimeout($func($arguments),0);
            }
        }
        while(count($this->once[$eventName]) > 0){
            $func = $this->once[$eventName]->dequeue();
            $this->setTimeout($func($arguments),0);
        }
    }

    public function once($eventName, $callback) {
        if(empty($this->once[$eventName])){
            $this->once[$eventName] = new SplQueue();
            $this->once[$eventName]->setIteratorMode($this->iteratorMode);
        }
        $cb = function($arguments) use($callback) {
            return function() use($callback,$arguments){
                call_user_func($callback,$arguments);
            };
        };
        $this->once[$eventName]->enqueue($cb);
    }

    public function removeListener(){

    }

    public function removeAllListeners($eventName){
        if ($eventName !== null) {
            unset($this->listeners[$eventName]);
        } else {
            $this->listeners = array();  
        }
    }

    public function listeners($eventName){
        return $this->observers[$eventName] ?: array();
    }

}

example.php

<?php

include('EventLoop.php');

$app = new EventLoop();

$closure = function($value) use($app) {
        $app->setInterval(function(){},0.01);
        return function() use($value){
                echo $value.PHP_EOL;
        };
};

$app->setTimeout($closure('timeout'),1);
$app->setInterval($closure('interval'),0.5);
$app->setInterval(function() use ($app) {
        echo 'MEMORY: '.memory_get_usage(true).PHP_EOL;
},2);

$app->run();

example2.php

<?php

include('EventLoop.php');

$app = new EventLoop();

$app->on('blah',function($args){
    print_r($args);
    echo 'blah'.PHP_EOL;
});

$app->once('blah',function($args){
    print_r($args);
    echo 'blah'.PHP_EOL;
});

$app->emit('blah',array('blah','blah2'));
$app->emit('blah',array('blah22','blah33'));

$app->run();