sorbetcms/classes/plugin.class.php

<?php
if (!defined('entry') || !entry) {
    die('Not a valid page');
}
/* ===========================

  gelato CMS - A PHP based tumblelog CMS
  development version
  http://www.gelatocms.com/

  gelato CMS is a free software licensed under the GPL 2.0
  Copyright (C) 2007 by Pedro Santana <pecesama at gmail dot com>

  =========================== */
?>
<?php
    class plugin
    {
        public $actions = array();
        public $exists = array();
    
        public function call($name)
        {
            if (!$this->exists($name)) {
                return false;
            }
            
            $index = 0;
            
            foreach ($GLOBALS['plugins::$instances'] as $plugin) {
                if (array_key_exists($index, $this->actions[$name])) {
                    $action = $this->actions[$name][$index][1];
                    if (is_callable(array($plugin, $action))) {
                        $plugin->$action();
                        $index++;
                    }
                }
            }
        }
        
        public function exists($name)
        {
            if (isset($this->exists[$name])) {
                return $this->exists[$name];
            }
            
            foreach ($GLOBALS['plugins::$instances'] as $plugin) {
                if (array_key_exists($name, $this->actions)) {
                    if (is_callable(array($plugin, $this->actions[$name][0][1]))) {
                        return $this->exists[$name] = true;
                    }
                }
            }

            return $this->exists[$name] = false;
        }
        
        //I really hate you PHP4's OOP implementation
        public function &instance()
        {
            static $instance;
            if (!isset($instance)) {
                $instance = new plugin();
            }
            return $instance;
        }
    }
?>