root/events/phpframework/codeigniter/trunk/system/libraries/Loader.php @ 18585

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
 * CodeIgniter
 *
 * An open source application development framework for PHP 4.3.2 or newer
 *
 * @package        CodeIgniter
 * @author        ExpressionEngine Dev Team
 * @copyright    Copyright (c) 2006, EllisLab, Inc.
 * @license        http://codeigniter.com/user_guide/license.html
 * @link        http://codeigniter.com
 * @since        Version 1.0
 * @filesource
 */

// ------------------------------------------------------------------------

/**
 * Loader Class
 *
 * Loads views and files
 *
 * @package        CodeIgniter
 * @subpackage    Libraries
 * @author        ExpressionEngine Dev Team
 * @category    Loader
 * @link        http://codeigniter.com/user_guide/libraries/loader.html
 */
class CI_Loader {

    // All these are set automatically. Don't mess with them.
    var $_ci_ob_level;
    var $_ci_view_path        = '';
    var $_ci_is_php5        = FALSE;
    var $_ci_is_instance     = FALSE; // Whether we should use $this or $CI =& get_instance()
    var $_ci_cached_vars    = array();
    var $_ci_classes        = array();
    var $_ci_models            = array();
    var $_ci_helpers        = array();
    var $_ci_plugins        = array();
    var $_ci_scripts        = array();
    var $_ci_varmap            = array('unit_test' => 'unit', 'user_agent' => 'agent');
    

    /**
     * Constructor
     *
     * Sets the path to the view files and gets the initial output buffering level
     *
     * @access    public
     */
    function CI_Loader()
    {    
        $this->_ci_is_php5 = (floor(phpversion()) >= 5) ? TRUE : FALSE;
        $this->_ci_view_path = APPPATH.'views/';
        $this->_ci_ob_level  = ob_get_level();
                
        log_message('debug', "Loader Class Initialized");
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Class Loader
     *
     * This function lets users load and instantiate classes.
     * It is designed to be called from a user's app controllers.
     *
     * @access    public
     * @param    string    the name of the class
     * @param    mixed    the optional parameters
     * @return    void
     */    
    function library($library = '', $params = NULL)
    {        
        if ($library == '')
        {
            return FALSE;
        }

        if (is_array($library))
        {
            foreach ($library as $class)
            {
                $this->_ci_load_class($class, $params);
            }
        }
        else
        {
            $this->_ci_load_class($library, $params);
        }
        
        $this->_ci_assign_to_models();
    }

    // --------------------------------------------------------------------
    
    /**
     * Model Loader
     *
     * This function lets users load and instantiate models.
     *
     * @param    string    the name of the class
     * @param    string    name for the model
     * @param    bool    database connection
     * @return    void
     */    
    function model($model, $name = '', $db_conn = FALSE)
    {        
        if (is_array($model))
        {
            foreach($model as $babe)
            {
                $this->model($babe);    
            }
            return;
        }

        if ($model == '')
        {
            return;
        }
    
        // Is the model in a sub-folder? If so, parse out the filename and path.
        if (strpos($model, '/') === FALSE)
        {
            $path = '';
        }
        else
        {
            $x = explode('/', $model);
            $model = end($x);            
            unset($x[count($x)-1]);
            $path = implode('/', $x).'/';
        }
    
        if ($name == '')
        {
            $name = $model;
        }
        
        if (in_array($name, $this->_ci_models, TRUE))
        {
            return;
        }
        
        $CI =& get_instance();
        if (isset($CI->$name))
        {
            show_error('The model name you are loading is the name of a resource that is already being used: '.$name);
        }
    
        $model = strtolower($model);
        
        if ( ! file_exists(APPPATH.'models/'.$path.$model.EXT))
        {
            show_error('Unable to locate the model you have specified: '.$model);
        }
                
        if ($db_conn !== FALSE AND ! class_exists('CI_DB'))
        {
            if ($db_conn === TRUE)
                $db_conn = '';
        
            $CI->load->database($db_conn, FALSE, TRUE);
        }
    
        if ( ! class_exists('Model'))
        {
            load_class('Model', FALSE);
        }

        require_once(APPPATH.'models/'.$path.$model.EXT);

        $model = ucfirst($model);
                
        $CI->$name = new $model();
        $CI->$name->_assign_libraries();
        
        $this->_ci_models[] = $name;    
    }
        
    // --------------------------------------------------------------------
    
    /**
     * Database Loader
     *
     * @access    public
     * @param    string    the DB credentials
     * @param    bool    whether to return the DB object
     * @param    bool    whether to enable active record (this allows us to override the config setting)
     * @return    object
     */    
    function database($params = '', $return = FALSE, $active_record = FALSE)
    {
        // Grab the super object
        $CI =& get_instance();
        
        // Do we even need to load the database class?
        if (class_exists('CI_DB') AND $return == FALSE AND $active_record == FALSE AND isset($CI->db) AND is_object($CI->db))
        {
            return FALSE;
        }    
    
        require_once(BASEPATH.'database/DB'.EXT);

        if ($return === TRUE)
        {
            return DB($params, $active_record);
        }
        
        // Initialize the db variable.  Needed to prevent   
        // reference errors with some configurations
        $CI->db = '';
        
        // Load the DB class
        $CI->db =& DB($params, $active_record);    
        
        // Assign the DB object to any existing models
        $this->_ci_assign_to_models();
    }
    
    // --------------------------------------------------------------------

    /**
     * Load the Utilities Class
     *
     * @access    public
     * @return    string        
     */        
    function dbutil()
    {
        if ( ! class_exists('CI_DB'))
        {
            $this->database();
        }
        
        $CI =& get_instance();

        // for backwards compatibility, load dbforge so we can extend dbutils off it
        // this use is deprecated and strongly discouraged
        $CI->load->dbforge();
    
        require_once(BASEPATH.'database/DB_utility'.EXT);
        require_once(BASEPATH.'database/drivers/'.$CI->db->dbdriver.'/'.$CI->db->dbdriver.'_utility'.EXT);
        $class = 'CI_DB_'.$CI->db->dbdriver.'_utility';

        $CI->dbutil =& new $class();

        $CI->load->_ci_assign_to_models();
    }
    
    // --------------------------------------------------------------------

    /**
     * Load the Database Forge Class
     *
     * @access    public
     * @return    string        
     */        
    function dbforge()
    {
        if ( ! class_exists('CI_DB'))
        {
            $this->database();
        }
        
        $CI =& get_instance();
    
        require_once(BASEPATH.'database/DB_forge'.EXT);
        require_once(BASEPATH.'database/drivers/'.$CI->db->dbdriver.'/'.$CI->db->dbdriver.'_forge'.EXT);
        $class = 'CI_DB_'.$CI->db->dbdriver.'_forge';

        $CI->dbforge = new $class();
        
        $CI->load->_ci_assign_to_models();
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Load View
     *
     * This function is used to load a "view" file.  It has three parameters:
     *
     * 1. The name of the "view" file to be included.
     * 2. An associative array of data to be extracted for use in the view.
     * 3. TRUE/FALSE - whether to return the data or load it.  In
     * some cases it's advantageous to be able to return data so that
     * a developer can process it in some way.
     *
     * @access    public
     * @param    string
     * @param    array
     * @param    bool
     * @return    void
     */
    function view($view, $vars = array(), $return = FALSE)
    {
        return $this->_ci_load(array('_ci_view' => $view, '_ci_vars' => $this->_ci_object_to_array($vars), '_ci_return' => $return));
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Load File
     *
     * This is a generic file loader
     *
     * @access    public
     * @param    string
     * @param    bool
     * @return    string
     */
    function file($path, $return = FALSE)
    {
        return $this->_ci_load(array('_ci_path' => $path, '_ci_return' => $return));
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Set Variables
     *
     * Once variables are set they become available within
     * the controller class and its "view" files.
     *
     * @access    public
     * @param    array
     * @return    void
     */
    function vars($vars = array())
    {
        $vars = $this->_ci_object_to_array($vars);
    
        if (is_array($vars) AND count($vars) > 0)
        {
            foreach ($vars as $key => $val)
            {
                $this->_ci_cached_vars[$key] = $val;
            }
        }
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Load Helper
     *
     * This function loads the specified helper file.
     *
     * @access    public
     * @param    mixed
     * @return    void
     */
    function helper($helpers = array())
    {
        if ( ! is_array($helpers))
        {
            $helpers = array($helpers);
        }
    
        foreach ($helpers as $helper)
        {        
            $helper = strtolower(str_replace(EXT, '', str_replace('_helper', '', $helper)).'_helper');
        
            if (isset($this->_ci_helpers[$helper]))
            {
                continue;
            }
            
            $ext_helper = APPPATH.'helpers/'.config_item('subclass_prefix').$helper.EXT;

            // Is this a helper extension request?            
            if (file_exists($ext_helper))
            {
                $base_helper = BASEPATH.'helpers/'.$helper.EXT;
                
                if ( ! file_exists($base_helper))
                {
                    show_error('Unable to load the requested file: helpers/'.$helper.EXT);
                }
                
                include_once($ext_helper);
                include_once($base_helper);
            }
            elseif (file_exists(APPPATH.'helpers/'.$helper.EXT))
            { 
                include_once(APPPATH.'helpers/'.$helper.EXT);
            }
            else
            {        
                if (file_exists(BASEPATH.'helpers/'.$helper.EXT))
                {
                    include_once(BASEPATH.'helpers/'.$helper.EXT);
                }
                else
                {
                    show_error('Unable to load the requested file: helpers/'.$helper.EXT);
                }
            }

            $this->_ci_helpers[$helper] = TRUE;
            
        }
        
        log_message('debug', 'Helpers loaded: '.implode(', ', $helpers));
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Load Helpers
     *
     * This is simply an alias to the above function in case the
     * user has written the plural form of this function.
     *
     * @access    public
     * @param    array
     * @return    void
     */
    function helpers($helpers = array())
    {
        $this->helper($helpers);
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Load Plugin
     *
     * This function loads the specified plugin.
     *
     * @access    public
     * @param    array
     * @return    void
     */
    function plugin($plugins = array())
    {
        if ( ! is_array($plugins))
        {
            $plugins = array($plugins);
        }
    
        foreach ($plugins as $plugin)
        {    
            $plugin = strtolower(str_replace(EXT, '', str_replace('_pi', '', $plugin)).'_pi');        

            if (isset($this->_ci_plugins[$plugin]))
            {
                continue;
            }

            if (file_exists(APPPATH.'plugins/'.$plugin.EXT))
            {
                include_once(APPPATH.'plugins/'.$plugin.EXT);    
            }
            else
            {
                if (file_exists(BASEPATH.'plugins/'.$plugin.EXT))
                {
                    include_once(BASEPATH.'plugins/'.$plugin.EXT);    
                }
                else
                {
                    show_error('Unable to load the requested file: plugins/'.$plugin.EXT);
                }
            }
            
            $this->_ci_plugins[$plugin] = TRUE;
        }
        
        log_message('debug', 'Plugins loaded: '.implode(', ', $plugins));
    }

    // --------------------------------------------------------------------
    
    /**
     * Load Plugins
     *
     * This is simply an alias to the above function in case the
     * user has written the plural form of this function.
     *
     * @access    public
     * @param    array
     * @return    void
     */
    function plugins($plugins = array())
    {
        $this->plugin($plugins);
    }

    // --------------------------------------------------------------------
    
    /**
     * Load Script
     *
     * This function loads the specified include file from the
     * application/scripts/ folder.
     *
     * NOTE:  This feature has been deprecated but it will remain available
     * for legacy users.
     *
     * @access    public
     * @param    array
     * @return    void
     */
    function script($scripts = array())
    {
        if ( ! is_array($scripts))
        {
            $scripts = array($scripts);
        }
    
        foreach ($scripts as $script)
        {    
            $script = strtolower(str_replace(EXT, '', $script));

            if (isset($this->_ci_scripts[$script]))
            {
                continue;
            }
        
            if ( ! file_exists(APPPATH.'scripts/'.$script.EXT))
            {
                show_error('Unable to load the requested script: scripts/'.$script.EXT);
            }
            
            include_once(APPPATH.'scripts/'.$script.EXT);
        }
        
        log_message('debug', 'Scripts loaded: '.implode(', ', $scripts));
    }
        
    // --------------------------------------------------------------------
    
    /**
     * Loads a language file
     *
     * @access    public
     * @param    array
     * @param    string
     * @return    void
     */
    function language($file = array(), $lang = '')
    {
        $CI =& get_instance();

        if ( ! is_array($file))
        {
            $file = array($file);
        }

        foreach ($file as $langfile)
        {    
            $CI->lang->load($langfile, $lang);
        }
    }

    /**
     * Loads language files for scaffolding
     *
     * @access    public
     * @param    string
     * @return    arra
     */
    function scaffold_language($file = '', $lang = '', $return = FALSE)
    {
        $CI =& get_instance();
        return $CI->lang->load($file, $lang, $return);
    }
    
    // --------------------------------------------------------------------
    
    /**
     * Loads a config file
     *
     * @access    public
     * @param    string
     * @return    void
     */
    function config($file = '', $use_sections = FALSE, $fail_gracefully = FALSE)
    {            
        $CI =& get_instance();
        $CI->config->load($file, $use_sections, $fail_gracefully);
    }

    // --------------------------------------------------------------------
    
    /**
     * Scaffolding Loader
     *
     * This initializing function works a bit different than the
     * others. It doesn't load the class.  Instead, it simply
     * sets a flag indicating that scaffolding is allowed to be
     * used.  The actual scaffolding function below is
     * called by the front controller based on whether the
     * second segment of the URL matches the "secret" scaffolding
     * word stored in the application/config/routes.php
     *
     * @access    public
     * @param    string
     * @return    void
     */    
    function scaffolding($table = '')
    {        
        if ($table === FALSE)
        {
            show_error('You must include the name of the table you would like to access when you initialize scaffolding');
        }
        
        $CI =& get_instance();
        $CI->_ci_scaffolding = TRUE;
        $CI->_ci_scaff_table = $table;
    }

    // --------------------------------------------------------------------
        
    /**
     * Loader
     *
     * This function is used to load views and files.
     * Variables are prefixed with _ci_ to avoid symbol collision with
     * variables made available to view files
     *
     * @access    private
     * @param    array
     * @return    void
     */
    function _ci_load($_ci_data)
    {
        // Set the default data variables
        foreach (array('_ci_view', '_ci_vars', '_ci_path', '_ci_return') as $_ci_val)
        {
            $$_ci_val = ( ! isset($_ci_data[$_ci_val])) ? FALSE : $_ci_data[$_ci_val];
        }

        // Set the path to the requested file
        if ($_ci_path == '')
        {
            $_ci_ext = pathinfo($_ci_view, PATHINFO_EXTENSION);
            $_ci_file = ($_ci_ext == '') ? $_ci_view.EXT : $_ci_view;
            $_ci_path = $this->_ci_view_path.$_ci_file;
        }
        else
        {
            $_ci_x = explode('/', $_ci_path);
            $_ci_file = end($_ci_x);
        }
        
        if ( ! file_exists($_ci_path))
        {
            show_error('Unable to load the requested file: '.$_ci_file);
        }
    
        // This allows anything loaded using $this->load (views, files, etc.)
        // to become accessible from within the Controller and Model functions.
        // Only needed when running PHP 5
        
        if ($this->_ci_is_instance())
        {
            $_ci_CI =& get_instance();
            foreach (get_object_vars($_ci_CI) as $_ci_key => $_ci_var)
            {
                if ( ! isset($this->$_ci_key))
                {
                    $this->$_ci_key =& $_ci_CI->$_ci_key;
                }
            }
        }

        /*
         * Extract and cache variables
         *
         * You can either set variables using the dedicated $this->load_vars()
         * function or via the second parameter of this function. We'll merge
         * the two types and cache them so that views that are embedded within
         * other views can have access to these variables.
         */    
        if (is_array($_ci_vars))
        {
            $this->_ci_cached_vars = array_merge($this->_ci_cached_vars, $_ci_vars);
        }
        extract($this->_ci_cached_vars);
                
        /*
         * Buffer the output
         *
         * We buffer the output for two reasons:
         * 1. Speed. You get a significant speed boost.
         * 2. So that the final rendered template can be
         * post-processed by the output class.  Why do we
         * need post processing?  For one thing, in order to
         * show the elapsed page load time.  Unless we
         * can intercept the content right before it's sent to
         * the browser and then stop the timer it won't be accurate.
         */
        ob_start();
                
        // If the PHP installation does not support short tags we'll
        // do a little string replacement, changing the short tags
        // to standard PHP echo statements.
        
        if ((bool) @ini_get('short_open_tag') === FALSE AND config_item('rewrite_short_tags') == TRUE)
        {
            echo eval('?>'.preg_replace("/;*\s*\?>/", "; ?>", str_replace('<?=', '<?php echo ', file_get_contents($_ci_path))));
        }
        else
        {
            include($_ci_path); // include() vs include_once() allows for multiple views with the same name
        }
        
        log_message('debug', 'File loaded: '.$_ci_path);
        
        // Return the file data if requested
        if ($_ci_return === TRUE)
        {        
            $buffer = ob_get_contents();
            @ob_end_clean();
            return $buffer;
        }

        /*
         * Flush the buffer... or buff the flusher?
         *
         * In order to permit views to be nested within
         * other views, we need to flush the content back out whenever
         * we are beyond the first level of output buffering so that
         * it can be seen and included properly by the first included
         * template and any subsequent ones. Oy!
         *
         */    
        if (ob_get_level() > $this->_ci_ob_level + 1)
        {
            ob_end_flush();
        }
        else
        {
            // PHP 4 requires that we use a global
            global $OUT;
            $OUT->append_output(ob_get_contents());
            @ob_end_clean();
        }
    }

    // --------------------------------------------------------------------

    /**
     * Load class
     *
     * This function loads the requested class.
     *
     * @access    private
     * @param     string    the item that is being loaded
     * @param    mixed    any additional parameters
     * @return     void
     */
    function _ci_load_class($class, $params = NULL)
    {    
        // Get the class name
        $class = str_replace(EXT, '', $class);

        // We'll test for both lowercase and capitalized versions of the file name
        foreach (array(ucfirst($class), strtolower($class)) as $class)
        {
            $subclass = APPPATH.'libraries/'.config_item('subclass_prefix').$class.EXT;

            // Is this a class extension request?            
            if (file_exists($subclass))
            {
                $baseclass = BASEPATH.'libraries/'.ucfirst($class).EXT;
                
                if ( ! file_exists($baseclass))
                {
                    log_message('error', "Unable to load the requested class: ".$class);
                    show_error("Unable to load the requested class: ".$class);
                }

                // Safety:  Was the class already loaded by a previous call?
                if (in_array($subclass, $this->_ci_classes))
                {
                    $is_duplicate = TRUE;
                    log_message('debug', $class." class already loaded. Second attempt ignored.");
                    return;
                }
    
                include_once($baseclass);                
                include_once($subclass);
                $this->_ci_classes[] = $subclass;
    
                return $this->_ci_init_class($class, config_item('subclass_prefix'), $params);            
            }
        
            // Lets search for the requested library file and load it.
            $is_duplicate = FALSE;        
            for ($i = 1; $i < 3; $i++)
            {
                $path = ($i % 2) ? APPPATH : BASEPATH;    
                $filepath = $path.'libraries/'.$class.EXT;
                
                // Does the file exist?  No?  Bummer...
                if ( ! file_exists($filepath))
                {
                    continue;
                }
                
                // Safety:  Was the class already loaded by a previous call?
                if (in_array($filepath, $this->_ci_classes))
                {
                    $is_duplicate = TRUE;
                    log_message('debug', $class." class already loaded. Second attempt ignored.");
                    return;
                }
                
                include_once($filepath);
                $this->_ci_classes[] = $filepath;
                return $this->_ci_init_class($class, '', $params);
            }
        } // END FOREACH
        
        // If we got this far we were unable to find the requested class.
        // We do not issue errors if the load call failed due to a duplicate request
        if ($is_duplicate == FALSE)
        {
            log_message('error', "Unable to load the requested class: ".$class);
            show_error("Unable to load the requested class: ".$class);
        }
    }
    
    // --------------------------------------------------------------------

    /**
     * Instantiates a class
     *
     * @access    private
     * @param    string
     * @param    string
     * @return    null
     */
    function _ci_init_class($class, $prefix = '', $config = FALSE)
    {    
        $class = strtolower($class);
        
        // Is there an associated config file for this class?
        if ($config === NULL)
        {
            if (file_exists(APPPATH.'config/'.$class.EXT))
            {
                include_once(APPPATH.'config/'.$class.EXT);
            }
        }
        
        if ($prefix == '')
        {
            $name = (class_exists('CI_'.$class)) ? 'CI_'.$class : $class;
        }
        else
        {
            $name = $prefix.$class;
        }
        
        // Set the variable name we will assign the class to    
        $classvar = ( ! isset($this->_ci_varmap[$class])) ? $class : $this->_ci_varmap[$class];
                
        // Instantiate the class        
        $CI =& get_instance();
        if ($config !== NULL)
        {
            $CI->$classvar = new $name($config);
        }
        else
        {        
            $CI->$classvar = new $name;
        }    
    }     
    
    // --------------------------------------------------------------------
    
    /**
     * Autoloader
     *
     * The config/autoload.php file contains an array that permits sub-systems,
     * libraries, plugins, and helpers to be loaded automatically.
     *
     * @access    private
     * @param    array
     * @return    void
     */
    function _ci_autoloader()
    {    
        include_once(APPPATH.'config/autoload'.EXT);
        
        if ( ! isset($autoload))
        {
            return FALSE;
        }
        
        // Load any custom config file
        if (count($autoload['config']) > 0)
        {            
            $CI =& get_instance();
            foreach ($autoload['config'] as $key => $val)
            {
                $CI->config->load($val);
            }
        }        

        // Autoload plugins, helpers and languages
        foreach (array('helper', 'plugin', 'language') as $type)
        {            
            if (isset($autoload[$type]) AND count($autoload[$type]) > 0)
            {
                $this->$type($autoload[$type]);
            }        
        }



        // A little tweak to remain backward compatible
        // The $autoload['core'] item was deprecated
        if ( ! isset($autoload['libraries']))
        {
            $autoload['libraries'] = $autoload['core'];
        }
        
        // Load libraries
        if (isset($autoload['libraries']) AND count($autoload['libraries']) > 0)
        {
            // Load the database driver.
            if (in_array('database', $autoload['libraries']))
            {
                $this->database();
                $autoload['libraries'] = array_diff($autoload['libraries'], array('database'));
            }

            // Load scaffolding
            if (in_array('scaffolding', $autoload['libraries']))
            {
                $this->scaffolding();
                $autoload['libraries'] = array_diff($autoload['libraries'], array('scaffolding'));
            }
        
            // Load all other libraries
            foreach ($autoload['libraries'] as $item)
            {
                $this->library($item);
            }
        }        

        // Autoload models
        if (isset($autoload['model']))
        {
            $this->model($autoload['model']);
        }

    }
    
    // --------------------------------------------------------------------

    /**
     * Assign to Models
     *
     * Makes sure that anything loaded by the loader class (libraries, plugins, etc.)
     * will be available to models, if any exist.
     *
     * @access    private
     * @param    object
     * @return    array
     */
    function _ci_assign_to_models()
    {
        if (count($this->_ci_models) == 0)
        {
            return;
        }
    
        if ($this->_ci_is_instance())
        {
            $CI =& get_instance();
            foreach ($this->_ci_models as $model)
            {            
                $CI->$model->_assign_libraries();
            }
        }
        else
        {        
            foreach ($this->_ci_models as $model)
            {            
                $this->$model->_assign_libraries();
            }
        }
    }      

    // --------------------------------------------------------------------

    /**
     * Object to Array
     *
     * Takes an object as input and converts the class variables to array key/vals
     *
     * @access    private
     * @param    object
     * @return    array
     */
    function _ci_object_to_array($object)
    {
        return (is_object($object)) ? get_object_vars($object) : $object;
    }

    // --------------------------------------------------------------------

    /**
     * Determines whether we should use the CI instance or $this
     *
     * @access    private
     * @return    bool
     */
    function _ci_is_instance()
    {
        if ($this->_ci_is_php5 == TRUE)
        {
            return TRUE;
        }
    
        global $CI;
        return (is_object($CI)) ? TRUE : FALSE;
    }
    
}

/* End of file Loader.php */
/* Location: ./system/libraries/Loader.php */