Events.php

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<?php
/*
 You may not change or alter any portion of this comment or credits
 of supporting developers from this source code or any supporting source code
 which is considered copyrighted (c) material of the original comment or credit authors.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*/

namespace Xoops\Core;

class Events
{
    protected $preloadList = array();

    protected $eventListeners = array();

    protected $eventsEnabled = true;

    protected function __construct()
    {
    }

    public static function getInstance()
    {
        static $instance = false;

        if (!$instance) {
            $instance = new \Xoops\Core\Events();
        }

        return $instance;
    }

    public function initializeListeners()
    {
        $this->eventsEnabled = false;
        $this->setPreloads();
        $this->setEvents();
        $this->eventsEnabled = true;
    }

    protected function setPreloads()
    {
        $cache = \Xoops::getInstance()->cache();
        $key = 'system/modules/preloads';
        if (!$this->preloadList = $cache->read($key)) {
            // get active modules from the xoops instance
            $modules_list = \Xoops::getInstance()->getActiveModules();
            if (empty($modules_list)) {
                // this should only happen if an exception was thrown in setActiveModules()
                $modules_list = array ('system');
            }
            $this->preloadList =array();
            $i = 0;
            foreach ($modules_list as $module) {
                if (is_dir($dir = \XoopsBaseConfig::get('root-path') . "/modules/{$module}/preloads/")) {
                    $file_list = \XoopsLists::getFileListAsArray($dir);
                    foreach ($file_list as $file) {
                        if (preg_match('/(\.php)$/i', $file)) {
                            $file = substr($file, 0, -4);
                            $this->preloadList[$i]['module'] = $module;
                            $this->preloadList[$i]['file'] = $file;
                            ++$i;
                        }
                    }
                }
            }
            $cache->write($key, $this->preloadList);
        }
    }

    protected function setEvents()
    {
        foreach ($this->preloadList as $preload) {
            include_once \XoopsBaseConfig::get('root-path') . '/modules/' . $preload['module'] . '/preloads/' . $preload['file']. '.php';
            $class_name = ucfirst($preload['module'])
                . ($preload['file'] == 'preload' ? '' : ucfirst($preload['file']) )
                . 'Preload';
            if (!class_exists($class_name)) {
                continue;
            }
            $class_methods = get_class_methods($class_name);
            foreach ($class_methods as $method) {
                if (strpos($method, 'event') === 0) {
                    $eventName = strtolower(str_replace('event', '', $method));
                    $event = array($class_name, $method);
                    $this->eventListeners[$eventName][] = $event;
                }
            }
        }
    }

    public function triggerEvent($eventName, $args = array())
    {
        if ($this->eventsEnabled) {
            $eventName = $this->toInternalEventName($eventName);
            if (isset($this->eventListeners[$eventName])) {
                foreach ($this->eventListeners[$eventName] as $event) {
                    if (is_callable($event)) {
                        call_user_func($event, $args);
                    }
                }
            }
        }
    }

    protected function toInternalEventName($eventName)
    {
        return strtolower(str_replace('.', '', $eventName));
    }

    public function addListener($eventName, $callback)
    {
        $eventName = $this->toInternalEventName($eventName);
        $this->eventListeners[$eventName][]=$callback;
    }

    public function getEvents()
    {
        return $this->eventListeners;
    }

    public function hasListeners($eventName)
    {
        $eventName = $this->toInternalEventName($eventName);
        return array_key_exists($eventName, $this->eventListeners);
    }
}