<?php
/**
* @package VikWP - Libraries
* @subpackage adapter.event
* @author E4J s.r.l.
* @copyright Copyright (C) 2023 E4J s.r.l. All Rights Reserved.
* @license http://www.gnu.org/licenses/gpl-2.0.html GNU/GPL
* @link https://vikwp.com
*/
// No direct access
defined('ABSPATH') or die('No script kiddies please!');
JLoader::import('adapter.event.event');
/**
* Class to handle dispatching of events.
*
* @since 10.1.11
*/
class JEventDispatcher
{
/**
* Stores the singleton instance of the dispatcher.
*
* @var JEventDispatcher
*/
protected static $instance = null;
/**
* A list of observed classes.
*
* @var string
*/
protected $observers = array();
/**
* Returns the global Event Dispatcher object, only creating it
* if it doesn't already exist.
*
* @return JEventDispatcher The EventDispatcher object.
*/
public static function getInstance()
{
if (self::$instance === null)
{
self::$instance = new static();
}
return self::$instance;
}
/**
* Triggers an event by dispatching arguments to all observers that handle
* the event and returning their return values.
*
* @param string $event The event to trigger.
* @param array $args An array of arguments.
*
* @return array An array of results from each called function.
*/
public function trigger($event, $args = array())
{
// make sure we are passing an array of arguments
$args = (array) $args;
// Push an empty value at the beginning of the list for being
// manipulated at every execution of the filter.
array_unshift($args, null);
/**
* Check whether the specified event uses the Joomla notation.
* In that case, rebuild the event to look more similar to
* WordPress hooks.
*
* @since 10.1.32
*/
if (preg_match("/^on[A-Z]/", $event))
{
$bc = $event;
// obtain WP hook version
$event = $this->getHook($event);
// check whether someone is using a deprecated hook
if (has_filter($bc))
{
// trigger warning to inform the user that a manual adjustment is needed
trigger_error(
sprintf('expected <b>%s</b> hook, <b>%s</b> given', $event, $bc),
E_USER_WARNING
);
/**
* Trigger the event for backward compatibility.
* Assign the returned value to the first argument,
* so that other plugins assigned to the correct
* hook will be able to manipulate it.
*
* @since 10.1.32
*
* @deprecated 10.2 Use the correct hook instead.
*/
$args[0] = apply_filters_ref_array($bc, $args);
}
}
/**
* Trigger the event.
* Use `apply_filters_ref_array` instead of `do_action_ref_array`
* to start supporting return values.
*
* @since 10.1.23
*/
$return = apply_filters_ref_array($event, $args);
if (is_null($return))
{
// return an empty list as none manipulated the return value
return array();
}
// push the returned value within a list for Joomla standards
return array($return);
}
/**
* Registers an event handler to the event dispatcher
*
* @param string $event Name of the event to register handler for.
* @param string $handler Name of the event handler.
*
* @return void
*
* @since 10.1.30
* @throws InvalidArgumentException
*/
public function register($event, $handler)
{
// are we dealing with a class or callback type handler?
if (is_callable($handler))
{
// function type event handler, let's attach it
$method = array('event' => $event, 'handler' => $handler);
$this->attach($method);
}
else if (class_exists($handler))
{
// class type event handler, let's instantiate and attach it
$this->attach(new $handler($this));
}
else
{
throw new InvalidArgumentException('Invalid event handler.');
}
}
/**
* Attach an observer object.
*
* @param mixed $observer An observer object to attach.
*
* @return void
*
* @since 10.1.29
*/
public function attach($observer)
{
if (is_array($observer))
{
if (!isset($observer['handler']) || !isset($observer['event']) || !is_callable($observer['handler']))
{
return;
}
// make sure we haven't already attached this array as an observer
foreach ($this->observers as $check)
{
if (is_array($check) && $check['event'] === $observer['event'] && $check['handler'] === $observer['handler'])
{
// callback already registered
return;
}
}
// obtain callback reflection and retrieve arguments
$reflection = new ReflectionFunction($observer['handler']);
$params = $reflection->getParameters();
// Register filter.
// Always increase parameters counter by one in order to
// accept the return value, which is never passed on Joomla.
add_filter($observer['event'], $observer['handler'], 10, count($params) + 1);
}
else
{
// make sure we haven't already attached this object as an observer
$class = get_class($observer);
foreach ($this->observers as $check)
{
if ($check instanceof $class)
{
// class already observed
return;
}
}
// obtain class reflection
$reflection = new ReflectionClass($observer);
// retrieve all methods
$methods = $reflection->getMethods();
// retrieve all JEvent methods
$default = get_class_methods('JEvent');
foreach ($methods as $method)
{
// make sure the method is not already used by the parent class,
// it is public and it is not static
if (!in_array($method->name, $default) && $method->isPublic() && !$method->isStatic())
{
// get method parameters
$params = $method->getParameters();
/**
* Refactor event name at runtime to support the
* WordPress hooks notation.
*
* @since 10.1.32
*/
$hook = $this->getHook($method->name);
// Register filter.
// Always increase parameters counter by one in order to
// accept the return value, which is never passed on Joomla.
add_filter($hook, array($observer, $method->name), 10, count($params) + 1);
}
}
}
// cache observer to avoid registering the same events more than once
$this->observers[] = $observer;
}
/**
* Checks whether the specified event uses the Joomla notation.
* In that case, rebuild the event to look more similar to
* WordPress hooks.
*
* @param string $event The event to check.
*
* @return string The modified event, if needed.
*
* @since 10.1.32
*/
protected function getHook($event)
{
// make sure it starts with "on"
if (preg_match("/^on[A-Z]/", $event))
{
// remove initial "on"
$event = preg_replace("/^on/", '', $event);
// recover option from request
$option = JFactory::getApplication()->input->get('option');
if ($option)
{
// clean "com_" from option
$option = preg_replace("/^com_/", '', $option);
// remove plugin name from event
$event = preg_replace("/{$option}/i", '', $event);
// always prepend plugin name at the beginning
$event = strtolower($option) . $event;
}
// place an underscore between each camelCase
$event = strtolower(preg_replace("/([a-z])([A-Z])/", '$1_$2', $event));
}
return $event;
}
}