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<?php
/**
* Matomo - free/libre analytics platform
*
* @link https://matomo.org
* @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
*
*/
namespace Piwik;
use Piwik\Container\StaticContainer;
/**
* This class allows code to post events from anywhere in Piwik and for
* plugins to associate callbacks to be executed when events are posted.
*/
class EventDispatcher
{
/**
* @return EventDispatcher
*/
public static function getInstance()
{
return StaticContainer::get('Piwik\EventDispatcher');
}
// implementation details for postEvent
const EVENT_CALLBACK_GROUP_FIRST = 0;
const EVENT_CALLBACK_GROUP_SECOND = 1;
const EVENT_CALLBACK_GROUP_THIRD = 2;
/**
* Array of observers (callbacks attached to events) that are not methods
* of plugin classes.
*
* @var array
*/
private $extraObservers = array();
/**
* Array storing information for all pending events. Each item in the array
* will be an array w/ two elements:
*
* array(
* 'Event.Name', // the event name
* array('event', 'parameters') // the parameters to pass to event observers
* )
*
* @var array
*/
private $pendingEvents = array();
/**
* Plugin\Manager instance used to get list of loaded plugins.
*
* @var \Piwik\Plugin\Manager
*/
private $pluginManager;
private $pluginHooks = array();
/**
* Constructor.
*/
public function __construct(Plugin\Manager $pluginManager, array $observers = array())
{
$this->pluginManager = $pluginManager;
foreach ($observers as $observerInfo) {
list($eventName, $callback) = $observerInfo;
$this->extraObservers[$eventName][] = $callback;
}
}
/**
* Triggers an event, executing all callbacks associated with it.
*
* @param string $eventName The name of the event, ie, API.getReportMetadata.
* @param array $params The parameters to pass to each callback when executing.
* @param bool $pending Whether this event should be posted again for plugins
* loaded after the event is fired.
* @param array|null $plugins The plugins to post events to. If null, the event
* is posted to all plugins. The elements of this array
* can be either the Plugin objects themselves
* or their string names.
*/
public function postEvent($eventName, $params, $pending = false, $plugins = null)
{
if ($pending) {
$this->pendingEvents[] = array($eventName, $params);
}
$manager = $this->pluginManager;
if (empty($plugins)) {
$plugins = $manager->getPluginsLoadedAndActivated();
}
$callbacks = array();
// collect all callbacks to execute
foreach ($plugins as $pluginName) {
if (!is_string($pluginName)) {
$pluginName = $pluginName->getPluginName();
}
if (!isset($this->pluginHooks[$pluginName])) {
$plugin = $manager->getLoadedPlugin($pluginName);
$this->pluginHooks[$pluginName] = $plugin->registerEvents();
}
$hooks = $this->pluginHooks[$pluginName];
if (isset($hooks[$eventName])) {
list($pluginFunction, $callbackGroup) = $this->getCallbackFunctionAndGroupNumber($hooks[$eventName]);
if (is_string($pluginFunction)) {
$plugin = $manager->getLoadedPlugin($pluginName);
$callbacks[$callbackGroup][] = array($plugin, $pluginFunction) ;
} else {
$callbacks[$callbackGroup][] = $pluginFunction;
}
}
}
if (isset($this->extraObservers[$eventName])) {
foreach ($this->extraObservers[$eventName] as $callbackInfo) {
list($callback, $callbackGroup) = $this->getCallbackFunctionAndGroupNumber($callbackInfo);
$callbacks[$callbackGroup][] = $callback;
}
}
// sort callbacks by their importance
ksort($callbacks);
// execute callbacks in order
foreach ($callbacks as $callbackGroup) {
foreach ($callbackGroup as $callback) {
call_user_func_array($callback, $params);
}
}
}
/**
* Associates a callback that is not a plugin class method with an event
* name.
*
* @param string $eventName
* @param array|callable $callback This can be a normal PHP callback or an array
* that looks like this:
* array(
* 'function' => $callback,
* 'before' => true
* )
* or this:
* array(
* 'function' => $callback,
* 'after' => true
* )
* If 'before' is set, the callback will be executed
* before normal & 'after' ones. If 'after' then it
* will be executed after normal ones.
*/
public function addObserver($eventName, $callback)
{
$this->extraObservers[$eventName][] = $callback;
}
/**
* Re-posts all pending events to the given plugin.
*
* @param Plugin $plugin
*/
public function postPendingEventsTo($plugin)
{
foreach ($this->pendingEvents as $eventInfo) {
[$eventName, $eventParams] = $eventInfo;
$this->postEvent($eventName, $eventParams, $pending = false, array($plugin));
}
}
/**
* @internal For testing purpose only
*/
public function clearCache()
{
$this->pluginHooks = [];
}
private function getCallbackFunctionAndGroupNumber($hookInfo)
{
if (is_array($hookInfo)
&& !empty($hookInfo['function'])
) {
$pluginFunction = $hookInfo['function'];
if (!empty($hookInfo['before'])) {
$callbackGroup = self::EVENT_CALLBACK_GROUP_FIRST;
} elseif (!empty($hookInfo['after'])) {
$callbackGroup = self::EVENT_CALLBACK_GROUP_THIRD;
} else {
$callbackGroup = self::EVENT_CALLBACK_GROUP_SECOND;
}
} else {
$pluginFunction = $hookInfo;
$callbackGroup = self::EVENT_CALLBACK_GROUP_SECOND;
}
return array($pluginFunction, $callbackGroup);
}
}
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