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EventManager.php
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EventManager.php
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<?php
/**
* Event Manager
*
* CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
* Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
*
* Licensed under The MIT License
* For full copyright and license information, please see the LICENSE.txt
* Redistributions of files must retain the above copyright notice.
*
* @copyright Copyright (c) Cake Software Foundation, Inc. (http://cakefoundation.org)
* @link http://cakephp.org CakePHP(tm) Project
* @since CakePHP(tm) v 2.1
* @license http://www.opensource.org/licenses/mit-license.php MIT License
*/
namespace Cake\Event;
use Cake\Error;
/**
* The event manager is responsible for keeping track of event listeners, passing the correct
* data to them, and firing them in the correct order, when associated events are triggered. You
* can create multiple instances of this object to manage local events or keep a single instance
* and pass it around to manage all events in your app.
*/
class EventManager {
/**
* The default priority queue value for new, attached listeners
*
* @var integer
*/
public static $defaultPriority = 10;
/**
* The globally available instance, used for dispatching events attached from any scope
*
* @var \Cake\Event\EventManager
*/
protected static $_generalManager = null;
/**
* List of listener callbacks associated to
*
* @var object $Listeners
*/
protected $_listeners = array();
/**
* Internal flag to distinguish a common manager from the singleton
*
* @var boolean
*/
protected $_isGlobal = false;
/**
* Returns the globally available instance of a Cake\Event\EventManager
* this is used for dispatching events attached from outside the scope
* other managers were created. Usually for creating hook systems or inter-class
* communication
*
* If called with the first parameter, it will be set as the globally available instance
*
* @param \Cake\Event\EventManager $manager
* @return \Cake\Event\EventManager the global event manager
*/
public static function instance($manager = null) {
if ($manager instanceof EventManager) {
static::$_generalManager = $manager;
}
if (empty(static::$_generalManager)) {
static::$_generalManager = new EventManager();
}
static::$_generalManager->_isGlobal = true;
return static::$_generalManager;
}
/**
* Adds a new listener to an event.
*
* @param callback|\Cake\Event\EventListener $callable PHP valid callback type or instance of Cake\Event\EventListener to be called
* when the event named with $eventKey is triggered. If a Cake\Event\EventListener instance is passed, then the `implementedEvents`
* method will be called on the object to register the declared events individually as methods to be managed by this class.
* It is possible to define multiple event handlers per event name.
*
* @param string $eventKey The event unique identifier name with which the callback will be associated. If $callable
* is an instance of Cake\Event\EventListener this argument will be ignored
*
* @param array $options used to set the `priority` flag to the listener. In the future more options may be added.
* Priorities are handled like queues, and multiple attachments added to the same priority queue will be treated in
* the order of insertion.
*
* @return void
* @throws \InvalidArgumentException When event key is missing or callable is not an
* instance of Cake\Event\EventListener.
*/
public function attach($callable, $eventKey = null, $options = array()) {
if (!$eventKey && !($callable instanceof EventListener)) {
throw new \InvalidArgumentException('The eventKey variable is required');
}
if ($callable instanceof EventListener) {
$this->_attachSubscriber($callable);
return;
}
$options = $options + array('priority' => static::$defaultPriority);
$this->_listeners[$eventKey][$options['priority']][] = array(
'callable' => $callable,
);
}
/**
* Auxiliary function to attach all implemented callbacks of a Cake\Event\EventListener class instance
* as individual methods on this manager
*
* @param \Cake\Event\EventListener $subscriber
* @return void
*/
protected function _attachSubscriber(EventListener $subscriber) {
foreach ((array)$subscriber->implementedEvents() as $eventKey => $function) {
$options = array();
$method = $function;
if (is_array($function) && isset($function['callable'])) {
list($method, $options) = $this->_extractCallable($function, $subscriber);
} elseif (is_array($function) && is_numeric(key($function))) {
foreach ($function as $f) {
list($method, $options) = $this->_extractCallable($f, $subscriber);
$this->attach($method, $eventKey, $options);
}
continue;
}
if (is_string($method)) {
$method = array($subscriber, $function);
}
$this->attach($method, $eventKey, $options);
}
}
/**
* Auxiliary function to extract and return a PHP callback type out of the callable definition
* from the return value of the `implementedEvents` method on a Cake\Event\EventListener
*
* @param array $function the array taken from a handler definition for an event
* @param \Cake\Event\EventListener $object The handler object
* @return callback
*/
protected function _extractCallable($function, $object) {
$method = $function['callable'];
$options = $function;
unset($options['callable']);
if (is_string($method)) {
$method = array($object, $method);
}
return array($method, $options);
}
/**
* Removes a listener from the active listeners.
*
* @param callback|\Cake\Event\EventListener $callable any valid PHP callback type or an instance of EventListener
* @param string $eventKey The event unique identifier name with which the callback has been associated
* @return void
*/
public function detach($callable, $eventKey = null) {
if ($callable instanceof EventListener) {
return $this->_detachSubscriber($callable, $eventKey);
}
if (empty($eventKey)) {
foreach (array_keys($this->_listeners) as $eventKey) {
$this->detach($callable, $eventKey);
}
return;
}
if (empty($this->_listeners[$eventKey])) {
return;
}
foreach ($this->_listeners[$eventKey] as $priority => $callables) {
foreach ($callables as $k => $callback) {
if ($callback['callable'] === $callable) {
unset($this->_listeners[$eventKey][$priority][$k]);
break;
}
}
}
}
/**
* Auxiliary function to help detach all listeners provided by an object implementing EventListener
*
* @param \Cake\Event\EventListener $subscriber the subscriber to be detached
* @param string $eventKey optional event key name to unsubscribe the listener from
* @return void
*/
protected function _detachSubscriber(EventListener $subscriber, $eventKey = null) {
$events = (array)$subscriber->implementedEvents();
if (!empty($eventKey) && empty($events[$eventKey])) {
return;
} elseif (!empty($eventKey)) {
$events = array($eventKey => $events[$eventKey]);
}
foreach ($events as $key => $function) {
if (is_array($function)) {
if (is_numeric(key($function))) {
foreach ($function as $handler) {
$handler = isset($handler['callable']) ? $handler['callable'] : $handler;
$this->detach(array($subscriber, $handler), $key);
}
continue;
}
$function = $function['callable'];
}
$this->detach(array($subscriber, $function), $key);
}
}
/**
* Dispatches a new event to all configured listeners
*
* @param string|\Cake\Event\Event $event the event key name or instance of Event
* @return void
*/
public function dispatch($event) {
if (is_string($event)) {
$event = new Event($event);
}
$listeners = $this->listeners($event->name());
if (empty($listeners)) {
return;
}
foreach ($listeners as $listener) {
if ($event->isStopped()) {
break;
}
$result = $this->_callListener($listener['callable'], $event);
if ($result === false) {
$event->stopPropagation();
}
if ($result !== null) {
$event->result = $result;
}
}
}
/**
* Calls a listener.
*
* Direct callback invocation is up to 30% faster than using call_user_func_array.
* Optimize the common cases to provide improved performance.
*
* @param callable $listener The listener to trigger.
* @param Event $event
* @return mixed The result of the $listener function.
*/
protected function _callListener(callable $listener, Event $event) {
$data = $event->data();
$length = count($data);
if ($length) {
$data = array_values($data);
}
switch ($length) {
case 0:
return $listener($event);
case 1:
return $listener($event, $data[0]);
case 2:
return $listener($event, $data[0], $data[1]);
case 3:
return $listener($event, $data[0], $data[1], $data[2]);
default:
array_unshift($data, $event);
return call_user_func_array($listener, $data);
}
}
/**
* Returns a list of all listeners for an eventKey in the order they should be called
*
* @param string $eventKey
* @return array
*/
public function listeners($eventKey) {
if (!$this->_isGlobal) {
$globalListeners = static::instance()->prioritisedListeners($eventKey);
} else {
$globalListeners = $this->prioritisedListeners($eventKey);
}
$listeners = array_merge($this->_listeners, self::instance()->_listeners);
if (empty($listeners[$eventKey]) && empty($globalListeners)) {
return [];
}
$listeners = $listeners[$eventKey];
foreach ($globalListeners as $priority => $priorityQ) {
if (!empty($listeners[$priority])) {
$listeners[$priority] = array_merge($priorityQ, $listeners[$priority]);
unset($globalListeners[$priority]);
}
}
$listeners = $listeners + $globalListeners;
ksort($listeners);
$result = array();
foreach ($listeners as $priorityQ) {
$result = array_merge($result, $priorityQ);
}
return $result;
}
/**
* Returns the listeners for the specified event key indexed by priority
*
* @param string $eventKey
* @return array
*/
public function prioritisedListeners($eventKey) {
if (empty($this->_listeners[$eventKey])) {
return array();
}
return $this->_listeners[$eventKey];
}
}