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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       * Gets the listener priority for a specific event.
  80       *
  81       * Returns null if the event or the listener does not exist.
  82       *
  83       * @param string   $eventName The name of the event
  84       * @param callable $listener  The listener
  85       *
  86       * @return int|null The event listener priority
  87       */
  88      public function getListenerPriority($eventName, $listener)
  89      {
  90          if (!isset($this->listeners[$eventName])) {
  91              return;
  92          }
  93  
  94          foreach ($this->listeners[$eventName] as $priority => $listeners) {
  95              if (false !== \in_array($listener, $listeners, true)) {
  96                  return $priority;
  97              }
  98          }
  99      }
 100  
 101      /**
 102       * {@inheritdoc}
 103       */
 104      public function hasListeners($eventName = null)
 105      {
 106          return (bool) $this->getListeners($eventName);
 107      }
 108  
 109      /**
 110       * {@inheritdoc}
 111       */
 112      public function addListener($eventName, $listener, $priority = 0)
 113      {
 114          $this->listeners[$eventName][$priority][] = $listener;
 115          unset($this->sorted[$eventName]);
 116      }
 117  
 118      /**
 119       * {@inheritdoc}
 120       */
 121      public function removeListener($eventName, $listener)
 122      {
 123          if (!isset($this->listeners[$eventName])) {
 124              return;
 125          }
 126  
 127          foreach ($this->listeners[$eventName] as $priority => $listeners) {
 128              if (false !== ($key = array_search($listener, $listeners, true))) {
 129                  unset($this->listeners[$eventName][$priority][$key], $this->sorted[$eventName]);
 130              }
 131          }
 132      }
 133  
 134      /**
 135       * {@inheritdoc}
 136       */
 137      public function addSubscriber(EventSubscriberInterface $subscriber)
 138      {
 139          foreach ($subscriber->getSubscribedEvents() as $eventName => $params) {
 140              if (\is_string($params)) {
 141                  $this->addListener($eventName, array($subscriber, $params));
 142              } elseif (\is_string($params[0])) {
 143                  $this->addListener($eventName, array($subscriber, $params[0]), isset($params[1]) ? $params[1] : 0);
 144              } else {
 145                  foreach ($params as $listener) {
 146                      $this->addListener($eventName, array($subscriber, $listener[0]), isset($listener[1]) ? $listener[1] : 0);
 147                  }
 148              }
 149          }
 150      }
 151  
 152      /**
 153       * {@inheritdoc}
 154       */
 155      public function removeSubscriber(EventSubscriberInterface $subscriber)
 156      {
 157          foreach ($subscriber->getSubscribedEvents() as $eventName => $params) {
 158              if (\is_array($params) && \is_array($params[0])) {
 159                  foreach ($params as $listener) {
 160                      $this->removeListener($eventName, array($subscriber, $listener[0]));
 161                  }
 162              } else {
 163                  $this->removeListener($eventName, array($subscriber, \is_string($params) ? $params : $params[0]));
 164              }
 165          }
 166      }
 167  
 168      /**
 169       * Triggers the listeners of an event.
 170       *
 171       * This method can be overridden to add functionality that is executed
 172       * for each listener.
 173       *
 174       * @param callable[] $listeners The event listeners
 175       * @param string     $eventName The name of the event to dispatch
 176       * @param Event      $event     The event object to pass to the event handlers/listeners
 177       */
 178      protected function doDispatch($listeners, $eventName, Event $event)
 179      {
 180          foreach ($listeners as $listener) {
 181              if ($event->isPropagationStopped()) {
 182                  break;
 183              }
 184              \call_user_func($listener, $event, $eventName, $this);
 185          }
 186      }
 187  
 188      /**
 189       * Sorts the internal list of listeners for the given event by priority.
 190       *
 191       * @param string $eventName The name of the event
 192       */
 193      private function sortListeners($eventName)
 194      {
 195          krsort($this->listeners[$eventName]);
 196          $this->sorted[$eventName] = \call_user_func_array('array_merge', $this->listeners[$eventName]);
 197      }
 198  }