Your IP : 216.73.216.182
<?php
namespace YOOtheme;
class EventDispatcher
{
/**
* @var array
*/
protected $handlers = [];
/**
* @var array
*/
protected $listeners = [];
/**
* Constructor.
*
* @param array $handlers
*/
public function __construct(array $handlers = [])
{
$this->handlers = $handlers + [
'filter' => [$this, 'handleFilter'],
'default' => [$this, 'handleDefault'],
'middleware' => [$this, 'handleMiddleware'],
];
}
/**
* Dispatches an event with arguments.
*
* @param string $event
* @param array $arguments
*
* @return mixed
*/
public function dispatch($event, ...$arguments)
{
list($event, $type) = explode('|', $event, 2) + [1 => 'default'];
$handler = isset($this->handlers[$type])
? $this->handlers[$type]
: $this->handlers['default'];
return $handler($this->getListeners($event), $arguments);
}
/**
* Gets the event listeners.
*
* @param string $event
*
* @return array
*/
public function getListeners($event)
{
return !empty($this->listeners[$event]) ? array_merge(...$this->listeners[$event]) : [];
}
/**
* Adds an event listener.
*
* @param string $event
* @param callable $listener
* @param int $priority
*/
public function addListener($event, $listener, $priority = 0)
{
$exists = isset($this->listeners[$event][$priority]);
$this->listeners[$event][$priority][] = $listener;
if (!$exists) {
krsort($this->listeners[$event]);
}
}
/**
* Removes an event listener.
*
* @param string $event
* @param callable $listener
*
* @return bool
*/
public function removeListener($event, $listener = null)
{
if (($result = is_null($listener)) || !isset($this->listeners[$event])) {
$this->listeners[$event] = [];
}
foreach ($this->listeners[$event] as $priority => &$listeners) {
if (is_int($key = array_search($listener, $listeners, true))) {
array_splice($listeners, $key, 1);
return true;
}
}
return $result;
}
/**
* The default handler calls every listener ordered by the priority.
*
* @param array $listeners
* @param array $arguments
*
* @return mixed
*/
protected function handleDefault(array $listeners, array $arguments = [])
{
$result = null;
foreach ($listeners as $listener) {
$_result = $listener(...$arguments);
// stop event propagation?
if ($_result === false) {
break;
}
if (isset($_result)) {
$result = $_result;
}
}
return $result;
}
/**
* The filter handler calls every listener ordered by the priority. It passes the return value from each listener to the next listener.
*
* @param array $listeners
* @param array $arguments
*
* @return mixed
*/
protected function handleFilter(array $listeners, array $arguments = [])
{
if (!$arguments) {
throw new \InvalidArgumentException('Filter must have at least one argument');
}
foreach ($listeners as $listener) {
$arguments[0] = $listener(...$arguments);
}
return $arguments[0];
}
/**
* The middleware handler calls every listener with arguments and a next() function which is invoked to execute the "next" middleware function.
*
* @param array $listeners
* @param array $arguments
*
* @return mixed
*/
protected function handleMiddleware(array $listeners, array $arguments = [])
{
if (!$arguments) {
throw new \InvalidArgumentException('Middleware must have at least one argument');
}
if (!is_callable($arguments[0])) {
throw new \InvalidArgumentException(
'Middleware must have a callable as first argument'
);
}
$middleware = new Middleware(array_shift($arguments), $listeners);
return $middleware(...$arguments);
}
}