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   1  <?php
   2  
   3  /*
   4   * This file is part of the Symfony package.
   5   *
   6   * (c) Fabien Potencier <fabien@symfony.com>
   7   *
   8   * For the full copyright and license information, please view the LICENSE
   9   * file that was distributed with this source code.
  10   */
  11  
  12  namespace Symfony\Component\EventDispatcher;
  13  
  14  /**
  15   * The EventDispatcherInterface is the central point of Symfony's event listener system.
  16   *
  17   * Listeners are registered on the manager and events are dispatched through the
  18   * manager.
  19   *
  20   * @author Guilherme Blanco <guilhermeblanco@hotmail.com>
  21   * @author Jonathan Wage <jonwage@gmail.com>
  22   * @author Roman Borschel <roman@code-factory.org>
  23   * @author Bernhard Schussek <bschussek@gmail.com>
  24   * @author Fabien Potencier <fabien@symfony.com>
  25   * @author Jordi Boggiano <j.boggiano@seld.be>
  26   * @author Jordan Alliot <jordan.alliot@gmail.com>
  27   */
  28  class EventDispatcher implements EventDispatcherInterface
  29  {
  30      private $listeners = array();
  31      private $sorted = array();
  32  
  33      /**
  34       * {@inheritdoc}
  35       */
  36      public function dispatch($eventName, Event $event = null)
  37      {
  38          if (null === $event) {
  39              $event = new Event();
  40          }
  41  
  42          $event->setDispatcher($this);
  43          $event->setName($eventName);
  44  
  45          if ($listeners = $this->getListeners($eventName)) {
  46              $this->doDispatch($listeners, $eventName, $event);
  47          }
  48  
  49          return $event;
  50      }
  51  
  52      /**
  53       * {@inheritdoc}
  54       */
  55      public function getListeners($eventName = null)
  56      {
  57          if (null !== $eventName) {
  58              if (!isset($this->listeners[$eventName])) {
  59                  return array();
  60              }
  61  
  62              if (!isset($this->sorted[$eventName])) {
  63                  $this->sortListeners($eventName);
  64              }
  65  
  66              return $this->sorted[$eventName];
  67          }
  68  
  69          foreach ($this->listeners as $eventName => $eventListeners) {
  70              if (!isset($this->sorted[$eventName])) {
  71                  $this->sortListeners($eventName);
  72              }
  73          }
  74  
  75          return array_filter($this->sorted);
  76      }
  77  
  78      /**
  79       * {@inheritdoc}
  80       */
  81      public function hasListeners($eventName = null)
  82      {
  83          return (bool) count($this->getListeners($eventName));
  84      }
  85  
  86      /**
  87       * {@inheritdoc}
  88       */
  89      public function addListener($eventName, $listener, $priority = 0)
  90      {
  91          $this->listeners[$eventName][$priority][] = $listener;
  92          unset($this->sorted[$eventName]);
  93      }
  94  
  95      /**
  96       * {@inheritdoc}
  97       */
  98      public function removeListener($eventName, $listener)
  99      {
 100          if (!isset($this->listeners[$eventName])) {
 101              return;
 102          }
 103  
 104          foreach ($this->listeners[$eventName] as $priority => $listeners) {
 105              if (false !== ($key = array_search($listener, $listeners, true))) {
 106                  unset($this->listeners[$eventName][$priority][$key], $this->sorted[$eventName]);
 107              }
 108          }
 109      }
 110  
 111      /**
 112       * {@inheritdoc}
 113       */
 114      public function addSubscriber(EventSubscriberInterface $subscriber)
 115      {
 116          foreach ($subscriber->getSubscribedEvents() as $eventName => $params) {
 117              if (is_string($params)) {
 118                  $this->addListener($eventName, array($subscriber, $params));
 119              } elseif (is_string($params[0])) {
 120                  $this->addListener($eventName, array($subscriber, $params[0]), isset($params[1]) ? $params[1] : 0);
 121              } else {
 122                  foreach ($params as $listener) {
 123                      $this->addListener($eventName, array($subscriber, $listener[0]), isset($listener[1]) ? $listener[1] : 0);
 124                  }
 125              }
 126          }
 127      }
 128  
 129      /**
 130       * {@inheritdoc}
 131       */
 132      public function removeSubscriber(EventSubscriberInterface $subscriber)
 133      {
 134          foreach ($subscriber->getSubscribedEvents() as $eventName => $params) {
 135              if (is_array($params) && is_array($params[0])) {
 136                  foreach ($params as $listener) {
 137                      $this->removeListener($eventName, array($subscriber, $listener[0]));
 138                  }
 139              } else {
 140                  $this->removeListener($eventName, array($subscriber, is_string($params) ? $params : $params[0]));
 141              }
 142          }
 143      }
 144  
 145      /**
 146       * Triggers the listeners of an event.
 147       *
 148       * This method can be overridden to add functionality that is executed
 149       * for each listener.
 150       *
 151       * @param array[callback] $listeners The event listeners.
 152       * @param string          $eventName The name of the event to dispatch.
 153       * @param Event           $event     The event object to pass to the event handlers/listeners.
 154       */
 155      protected function doDispatch($listeners, $eventName, Event $event)
 156      {
 157          foreach ($listeners as $listener) {
 158              if ($event->isPropagationStopped()) {
 159                  break;
 160              }
 161              call_user_func($listener, $event);
 162          }
 163      }
 164  
 165      /**
 166       * Sorts the internal list of listeners for the given event by priority.
 167       *
 168       * @param string $eventName The name of the event.
 169       */
 170      private function sortListeners($eventName)
 171      {
 172          $this->sorted[$eventName] = array();
 173  
 174          krsort($this->listeners[$eventName]);
 175          $this->sorted[$eventName] = call_user_func_array('array_merge', $this->listeners[$eventName]);
 176      }
 177  }