Merge tag '3.1.5' into dev-ci3

Signed-off-by: Florian Pritz <bluewind@xinu.at>

1 files changed, 684 insertions, 521 deletions

diff --git a/system/core/Loader.php b/system/core/Loader.php
index b5b0634e6..5ed6adb48 100644
--- a/system/core/Loader.php
+++ b/system/core/Loader.php
@@ -1,30 +1,52 @@
-<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+<?php
 /**
  * CodeIgniter
  *
- * An open source application development framework for PHP 5.1.6 or newer
+ * An open source application development framework for PHP
  *
- * @package		CodeIgniter
- * @author		ExpressionEngine Dev Team
- * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc.
- * @license		http://codeigniter.com/user_guide/license.html
- * @link		http://codeigniter.com
- * @since		Version 1.0
+ * This content is released under the MIT License (MIT)
+ *
+ * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ *
+ * @package	CodeIgniter
+ * @author	EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)
+ * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
+ * @license	http://opensource.org/licenses/MIT	MIT License
+ * @link	https://codeigniter.com
+ * @since	Version 1.0.0
  * @filesource
  */
-
-// ------------------------------------------------------------------------
+defined('BASEPATH') OR exit('No direct script access allowed');
 
 /**
  * Loader Class
  *
- * Loads views and files
+ * Loads framework components.
  *
  * @package		CodeIgniter
  * @subpackage	Libraries
- * @author		ExpressionEngine Dev Team
  * @category	Loader
- * @link		http://codeigniter.com/user_guide/libraries/loader.html
+ * @author		EllisLab Dev Team
+ * @link		https://codeigniter.com/user_guide/libraries/loader.html
  */
 class CI_Loader {
 
@@ -32,126 +54,107 @@ class CI_Loader {
 	/**
 	 * Nesting level of the output buffering mechanism
 	 *
-	 * @var int
-	 * @access protected
+	 * @var	int
 	 */
 	protected $_ci_ob_level;
+
 	/**
 	 * List of paths to load views from
 	 *
-	 * @var array
-	 * @access protected
+	 * @var	array
 	 */
-	protected $_ci_view_paths		= array();
+	protected $_ci_view_paths =	array(VIEWPATH	=> TRUE);
+
 	/**
 	 * List of paths to load libraries from
 	 *
-	 * @var array
-	 * @access protected
+	 * @var	array
 	 */
-	protected $_ci_library_paths	= array();
+	protected $_ci_library_paths =	array(APPPATH, BASEPATH);
+
 	/**
 	 * List of paths to load models from
 	 *
-	 * @var array
-	 * @access protected
+	 * @var	array
 	 */
-	protected $_ci_model_paths		= array();
+	protected $_ci_model_paths =	array(APPPATH);
+
 	/**
 	 * List of paths to load helpers from
 	 *
-	 * @var array
-	 * @access protected
+	 * @var	array
 	 */
-	protected $_ci_helper_paths		= array();
-	/**
-	 * List of loaded base classes
-	 * Set by the controller class
-	 *
-	 * @var array
-	 * @access protected
-	 */
-	protected $_base_classes		= array(); // Set by the controller class
+	protected $_ci_helper_paths =	array(APPPATH, BASEPATH);
+
 	/**
 	 * List of cached variables
 	 *
-	 * @var array
-	 * @access protected
+	 * @var	array
 	 */
-	protected $_ci_cached_vars		= array();
+	protected $_ci_cached_vars =	array();
+
 	/**
 	 * List of loaded classes
 	 *
-	 * @var array
-	 * @access protected
+	 * @var	array
 	 */
-	protected $_ci_classes			= array();
-	/**
-	 * List of loaded files
-	 *
-	 * @var array
-	 * @access protected
-	 */
-	protected $_ci_loaded_files		= array();
+	protected $_ci_classes =	array();
+
 	/**
 	 * List of loaded models
 	 *
-	 * @var array
-	 * @access protected
+	 * @var	array
 	 */
-	protected $_ci_models			= array();
+	protected $_ci_models =	array();
+
 	/**
 	 * List of loaded helpers
 	 *
-	 * @var array
-	 * @access protected
+	 * @var	array
 	 */
-	protected $_ci_helpers			= array();
+	protected $_ci_helpers =	array();
+
 	/**
 	 * List of class name mappings
 	 *
-	 * @var array
-	 * @access protected
+	 * @var	array
 	 */
-	protected $_ci_varmap			= array('unit_test' => 'unit',
-											'user_agent' => 'agent');
+	protected $_ci_varmap =	array(
+		'unit_test' => 'unit',
+		'user_agent' => 'agent'
+	);
+
+	// --------------------------------------------------------------------
 
 	/**
-	 * Constructor
+	 * Class constructor
+	 *
+	 * Sets component load paths, gets the initial output buffering level.
 	 *
-	 * Sets the path to the view files and gets the initial output buffering level
+	 * @return	void
 	 */
 	public function __construct()
 	{
-		$this->_ci_ob_level  = ob_get_level();
-		$this->_ci_library_paths = array(APPPATH, BASEPATH);
-		$this->_ci_helper_paths = array(APPPATH, BASEPATH);
-		$this->_ci_model_paths = array(APPPATH);
-		$this->_ci_view_paths = array(APPPATH.'views/'	=> TRUE);
+		$this->_ci_ob_level = ob_get_level();
+		$this->_ci_classes =& is_loaded();
 
-		log_message('debug', "Loader Class Initialized");
+		log_message('info', 'Loader Class Initialized');
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Initialize the Loader
-	 *
-	 * This method is called once in CI_Controller.
+	 * Initializer
 	 *
-	 * @param 	array
-	 * @return 	object
+	 * @todo	Figure out a way to move this to the constructor
+	 *		without breaking *package_path*() methods.
+	 * @uses	CI_Loader::_ci_autoloader()
+	 * @used-by	CI_Controller::__construct()
+	 * @return	void
 	 */
 	public function initialize()
 	{
-		$this->_ci_classes = array();
-		$this->_ci_loaded_files = array();
-		$this->_ci_models = array();
-		$this->_base_classes =& is_loaded();
-
 		$this->_ci_autoloader();
-
-		return $this;
 	}
 
 	// --------------------------------------------------------------------
@@ -159,61 +162,61 @@ class CI_Loader {
 	/**
 	 * Is Loaded
 	 *
-	 * A utility function to test if a class is in the self::$_ci_classes array.
-	 * This function returns the object name if the class tested for is loaded,
-	 * and returns FALSE if it isn't.
+	 * A utility method to test if a class is in the self::$_ci_classes array.
 	 *
-	 * It is mainly used in the form_helper -> _get_validation_object()
+	 * @used-by	Mainly used by Form Helper function _get_validation_object().
 	 *
-	 * @param 	string	class being checked for
-	 * @return 	mixed	class object name on the CI SuperObject or FALSE
+	 * @param 	string		$class	Class name to check for
+	 * @return 	string|bool	Class object name if loaded or FALSE
 	 */
 	public function is_loaded($class)
 	{
-		if (isset($this->_ci_classes[$class]))
-		{
-			return $this->_ci_classes[$class];
-		}
-
-		return FALSE;
+		return array_search(ucfirst($class), $this->_ci_classes, TRUE);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Class Loader
+	 * Library Loader
 	 *
-	 * This function lets users load and instantiate classes.
-	 * It is designed to be called from a user's app controllers.
+	 * Loads and instantiates libraries.
+	 * Designed to be called from application controllers.
 	 *
-	 * @param	string	the name of the class
-	 * @param	mixed	the optional parameters
-	 * @param	string	an optional object name
-	 * @return	void
+	 * @param	string	$library	Library name
+	 * @param	array	$params		Optional parameters to pass to the library class constructor
+	 * @param	string	$object_name	An optional object name to assign to
+	 * @return	object
 	 */
-	public function library($library = '', $params = NULL, $object_name = NULL)
+	public function library($library, $params = NULL, $object_name = NULL)
 	{
-		if (is_array($library))
+		if (empty($library))
+		{
+			return $this;
+		}
+		elseif (is_array($library))
 		{
-			foreach ($library as $class)
+			foreach ($library as $key => $value)
 			{
-				$this->library($class, $params);
+				if (is_int($key))
+				{
+					$this->library($value, $params);
+				}
+				else
+				{
+					$this->library($key, $params, $value);
+				}
 			}
 
-			return;
-		}
-
-		if ($library == '' OR isset($this->_base_classes[$library]))
-		{
-			return FALSE;
+			return $this;
 		}
 
-		if ( ! is_null($params) && ! is_array($params))
+		if ($params !== NULL && ! is_array($params))
 		{
 			$params = NULL;
 		}
 
-		$this->_ci_load_class($library, $params, $object_name);
+		$this->_ci_load_library($library, $params, $object_name);
+		return $this;
 	}
 
 	// --------------------------------------------------------------------
@@ -221,27 +224,27 @@ class CI_Loader {
 	/**
 	 * Model Loader
 	 *
-	 * This function lets users load and instantiate models.
+	 * Loads and instantiates models.
 	 *
-	 * @param	string	the name of the class
-	 * @param	string	name for the model
-	 * @param	bool	database connection
-	 * @return	void
+	 * @param	string	$model		Model name
+	 * @param	string	$name		An optional object name to assign to
+	 * @param	bool	$db_conn	An optional database connection configuration to initialize
+	 * @return	object
 	 */
 	public function model($model, $name = '', $db_conn = FALSE)
 	{
-		if (is_array($model))
+		if (empty($model))
 		{
-			foreach ($model as $babe)
+			return $this;
+		}
+		elseif (is_array($model))
+		{
+			foreach ($model as $key => $value)
 			{
-				$this->model($babe);
+				is_int($key) ? $this->model($value, '', $db_conn) : $this->model($key, $value, $db_conn);
 			}
-			return;
-		}
 
-		if ($model == '')
-		{
-			return;
+			return $this;
 		}
 
 		$path = '';
@@ -250,64 +253,105 @@ class CI_Loader {
 		if (($last_slash = strrpos($model, '/')) !== FALSE)
 		{
 			// The path is in front of the last slash
-			$path = substr($model, 0, $last_slash + 1);
+			$path = substr($model, 0, ++$last_slash);
 
 			// And the model name behind it
-			$model = substr($model, $last_slash + 1);
+			$model = substr($model, $last_slash);
 		}
 
-		if ($name == '')
+		if (empty($name))
 		{
 			$name = $model;
 		}
 
 		if (in_array($name, $this->_ci_models, TRUE))
 		{
-			return;
+			return $this;
 		}
 
 		$CI =& get_instance();
 		if (isset($CI->$name))
 		{
-			show_error('The model name you are loading is the name of a resource that is already being used: '.$name);
+			throw new RuntimeException('The model name you are loading is the name of a resource that is already being used: '.$name);
 		}
 
-		$model = strtolower($model);
-
-		foreach ($this->_ci_model_paths as $mod_path)
+		if ($db_conn !== FALSE && ! class_exists('CI_DB', FALSE))
 		{
-			if ( ! file_exists($mod_path.'models/'.$path.$model.'.php'))
+			if ($db_conn === TRUE)
 			{
-				continue;
+				$db_conn = '';
 			}
 
-			if ($db_conn !== FALSE AND ! class_exists('CI_DB'))
+			$this->database($db_conn, FALSE, TRUE);
+		}
+
+		// Note: All of the code under this condition used to be just:
+		//
+		//       load_class('Model', 'core');
+		//
+		//       However, load_class() instantiates classes
+		//       to cache them for later use and that prevents
+		//       MY_Model from being an abstract class and is
+		//       sub-optimal otherwise anyway.
+		if ( ! class_exists('CI_Model', FALSE))
+		{
+			$app_path = APPPATH.'core'.DIRECTORY_SEPARATOR;
+			if (file_exists($app_path.'Model.php'))
 			{
-				if ($db_conn === TRUE)
+				require_once($app_path.'Model.php');
+				if ( ! class_exists('CI_Model', FALSE))
 				{
-					$db_conn = '';
+					throw new RuntimeException($app_path."Model.php exists, but doesn't declare class CI_Model");
 				}
-
-				$CI->load->database($db_conn, FALSE, TRUE);
+			}
+			elseif ( ! class_exists('CI_Model', FALSE))
+			{
+				require_once(BASEPATH.'core'.DIRECTORY_SEPARATOR.'Model.php');
 			}
 
-			if ( ! class_exists('CI_Model'))
+			$class = config_item('subclass_prefix').'Model';
+			if (file_exists($app_path.$class.'.php'))
 			{
-				load_class('Model', 'core');
+				require_once($app_path.$class.'.php');
+				if ( ! class_exists($class, FALSE))
+				{
+					throw new RuntimeException($app_path.$class.".php exists, but doesn't declare class ".$class);
+				}
 			}
+		}
 
-			require_once($mod_path.'models/'.$path.$model.'.php');
+		$model = ucfirst($model);
+		if ( ! class_exists($model, FALSE))
+		{
+			foreach ($this->_ci_model_paths as $mod_path)
+			{
+				if ( ! file_exists($mod_path.'models/'.$path.$model.'.php'))
+				{
+					continue;
+				}
 
-			$model = ucfirst($model);
+				require_once($mod_path.'models/'.$path.$model.'.php');
+				if ( ! class_exists($model, FALSE))
+				{
+					throw new RuntimeException($mod_path."models/".$path.$model.".php exists, but doesn't declare class ".$model);
+				}
 
-			$CI->$name = new $model();
+				break;
+			}
 
-			$this->_ci_models[] = $name;
-			return;
+			if ( ! class_exists($model, FALSE))
+			{
+				throw new RuntimeException('Unable to locate the model you have specified: '.$model);
+			}
+		}
+		elseif ( ! is_subclass_of($model, 'CI_Model'))
+		{
+			throw new RuntimeException("Class ".$model." already exists and doesn't extend CI_Model");
 		}
 
-		// couldn't find the model
-		show_error('Unable to locate the model you have specified: '.$model);
+		$this->_ci_models[] = $name;
+		$CI->$name = new $model();
+		return $this;
 	}
 
 	// --------------------------------------------------------------------
@@ -315,18 +359,21 @@ class CI_Loader {
 	/**
 	 * Database Loader
 	 *
-	 * @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
+	 * @param	mixed	$params		Database configuration options
+	 * @param	bool	$return 	Whether to return the database object
+	 * @param	bool	$query_builder	Whether to enable Query Builder
+	 *					(overrides the configuration setting)
+	 *
+	 * @return	object|bool	Database object if $return is set to TRUE,
+	 *					FALSE on failure, CI_Loader instance in any other case
 	 */
-	public function database($params = '', $return = FALSE, $active_record = NULL)
+	public function database($params = '', $return = FALSE, $query_builder = NULL)
 	{
 		// 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 $active_record == NULL AND isset($CI->db) AND is_object($CI->db))
+		if ($return === FALSE && $query_builder === NULL && isset($CI->db) && is_object($CI->db) && ! empty($CI->db->conn_id))
 		{
 			return FALSE;
 		}
@@ -335,42 +382,48 @@ class CI_Loader {
 
 		if ($return === TRUE)
 		{
-			return DB($params, $active_record);
+			return DB($params, $query_builder);
 		}
 
-		// Initialize the db variable.  Needed to prevent
+		// Initialize the db variable. Needed to prevent
 		// reference errors with some configurations
 		$CI->db = '';
 
 		// Load the DB class
-		$CI->db =& DB($params, $active_record);
+		$CI->db =& DB($params, $query_builder);
+		return $this;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Load the Utilities Class
+	 * Load the Database Utilities Class
 	 *
-	 * @return	string
+	 * @param	object	$db	Database object
+	 * @param	bool	$return	Whether to return the DB Utilities class object or not
+	 * @return	object
 	 */
-	public function dbutil()
+	public function dbutil($db = NULL, $return = FALSE)
 	{
-		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
-		$CI->load->dbforge();
+		if ( ! is_object($db) OR ! ($db instanceof CI_DB))
+		{
+			class_exists('CI_DB', FALSE) OR $this->database();
+			$db =& $CI->db;
+		}
 
 		require_once(BASEPATH.'database/DB_utility.php');
-		require_once(BASEPATH.'database/drivers/'.$CI->db->dbdriver.'/'.$CI->db->dbdriver.'_utility.php');
-		$class = 'CI_DB_'.$CI->db->dbdriver.'_utility';
+		require_once(BASEPATH.'database/drivers/'.$db->dbdriver.'/'.$db->dbdriver.'_utility.php');
+		$class = 'CI_DB_'.$db->dbdriver.'_utility';
 
-		$CI->dbutil = new $class();
+		if ($return === TRUE)
+		{
+			return new $class($db);
+		}
+
+		$CI->dbutil = new $class($db);
+		return $this;
 	}
 
 	// --------------------------------------------------------------------
@@ -378,57 +431,72 @@ class CI_Loader {
 	/**
 	 * Load the Database Forge Class
 	 *
-	 * @return	string
+	 * @param	object	$db	Database object
+	 * @param	bool	$return	Whether to return the DB Forge class object or not
+	 * @return	object
 	 */
-	public function dbforge()
+	public function dbforge($db = NULL, $return = FALSE)
 	{
-		if ( ! class_exists('CI_DB'))
+		$CI =& get_instance();
+		if ( ! is_object($db) OR ! ($db instanceof CI_DB))
 		{
-			$this->database();
+			class_exists('CI_DB', FALSE) OR $this->database();
+			$db =& $CI->db;
 		}
 
-		$CI =& get_instance();
-
 		require_once(BASEPATH.'database/DB_forge.php');
-		require_once(BASEPATH.'database/drivers/'.$CI->db->dbdriver.'/'.$CI->db->dbdriver.'_forge.php');
-		$class = 'CI_DB_'.$CI->db->dbdriver.'_forge';
+		require_once(BASEPATH.'database/drivers/'.$db->dbdriver.'/'.$db->dbdriver.'_forge.php');
 
-		$CI->dbforge = new $class();
+		if ( ! empty($db->subdriver))
+		{
+			$driver_path = BASEPATH.'database/drivers/'.$db->dbdriver.'/subdrivers/'.$db->dbdriver.'_'.$db->subdriver.'_forge.php';
+			if (file_exists($driver_path))
+			{
+				require_once($driver_path);
+				$class = 'CI_DB_'.$db->dbdriver.'_'.$db->subdriver.'_forge';
+			}
+		}
+		else
+		{
+			$class = 'CI_DB_'.$db->dbdriver.'_forge';
+		}
+
+		if ($return === TRUE)
+		{
+			return new $class($db);
+		}
+
+		$CI->dbforge = new $class($db);
+		return $this;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Load View
+	 * View Loader
 	 *
-	 * This function is used to load a "view" file.  It has three parameters:
+	 * Loads "view" files.
 	 *
-	 * 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.
-	 *
-	 * @param	string
-	 * @param	array
-	 * @param	bool
-	 * @return	void
+	 * @param	string	$view	View name
+	 * @param	array	$vars	An associative array of data
+	 *				to be extracted for use in the view
+	 * @param	bool	$return	Whether to return the view output
+	 *				or leave it to the Output class
+	 * @return	object|string
 	 */
 	public function view($view, $vars = array(), $return = FALSE)
 	{
-		return $this->_ci_load(array('_ci_view' => $view, '_ci_vars' => $this->_ci_object_to_array($vars), '_ci_return' => $return));
+		return $this->_ci_load(array('_ci_view' => $view, '_ci_vars' => $this->_ci_prepare_view_vars($vars), '_ci_return' => $return));
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Load File
-	 *
-	 * This is a generic file loader
+	 * Generic File Loader
 	 *
-	 * @param	string
-	 * @param	bool
-	 * @return	string
+	 * @param	string	$path	File path
+	 * @param	bool	$return	Whether to return the file output
+	 * @return	object|string
 	 */
 	public function file($path, $return = FALSE)
 	{
@@ -443,26 +511,39 @@ class CI_Loader {
 	 * Once variables are set they become available within
 	 * the controller class and its "view" files.
 	 *
-	 * @param	array
-	 * @param 	string
-	 * @return	void
+	 * @param	array|object|string	$vars
+	 *					An associative array or object containing values
+	 *					to be set, or a value's name if string
+	 * @param 	string	$val	Value to set, only used if $vars is a string
+	 * @return	object
 	 */
-	public function vars($vars = array(), $val = '')
+	public function vars($vars, $val = '')
 	{
-		if ($val != '' AND is_string($vars))
+		$vars = is_string($vars)
+			? array($vars => $val)
+			: $this->_ci_prepare_view_vars($vars);
+
+		foreach ($vars as $key => $val)
 		{
-			$vars = array($vars => $val);
+			$this->_ci_cached_vars[$key] = $val;
 		}
 
-		$vars = $this->_ci_object_to_array($vars);
+		return $this;
+	}
 
-		if (is_array($vars) AND count($vars) > 0)
-		{
-			foreach ($vars as $key => $val)
-			{
-				$this->_ci_cached_vars[$key] = $val;
-			}
-		}
+	// --------------------------------------------------------------------
+
+	/**
+	 * Clear Cached Variables
+	 *
+	 * Clears the cached variables.
+	 *
+	 * @return	CI_Loader
+	 */
+	public function clear_vars()
+	{
+		$this->_ci_cached_vars = array();
+		return $this;
 	}
 
 	// --------------------------------------------------------------------
@@ -472,8 +553,8 @@ class CI_Loader {
 	 *
 	 * Check if a variable is set and retrieve it.
 	 *
-	 * @param	array
-	 * @return	void
+	 * @param	string	$key	Variable name
+	 * @return	mixed	The variable or NULL if not found
 	 */
 	public function get_var($key)
 	{
@@ -483,43 +564,68 @@ class CI_Loader {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Load Helper
+	 * Get Variables
 	 *
-	 * This function loads the specified helper file.
+	 * Retrieves all loaded variables.
 	 *
-	 * @param	mixed
-	 * @return	void
+	 * @return	array
+	 */
+	public function get_vars()
+	{
+		return $this->_ci_cached_vars;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Helper Loader
+	 *
+	 * @param	string|string[]	$helpers	Helper name(s)
+	 * @return	object
 	 */
 	public function helper($helpers = array())
 	{
-		foreach ($this->_ci_prep_filename($helpers, '_helper') as $helper)
+		is_array($helpers) OR $helpers = array($helpers);
+		foreach ($helpers as &$helper)
 		{
+			$filename = basename($helper);
+			$filepath = ($filename === $helper) ? '' : substr($helper, 0, strlen($helper) - strlen($filename));
+			$filename = strtolower(preg_replace('#(_helper)?(\.php)?$#i', '', $filename)).'_helper';
+			$helper   = $filepath.$filename;
+
 			if (isset($this->_ci_helpers[$helper]))
 			{
 				continue;
 			}
 
-			$ext_helper = APPPATH.'helpers/'.config_item('subclass_prefix').$helper.'.php';
-
 			// Is this a helper extension request?
-			if (file_exists($ext_helper))
+			$ext_helper = config_item('subclass_prefix').$filename;
+			$ext_loaded = FALSE;
+			foreach ($this->_ci_helper_paths as $path)
 			{
-				$base_helper = BASEPATH.'helpers/'.$helper.'.php';
+				if (file_exists($path.'helpers/'.$ext_helper.'.php'))
+				{
+					include_once($path.'helpers/'.$ext_helper.'.php');
+					$ext_loaded = TRUE;
+				}
+			}
 
+			// If we have loaded extensions - check if the base one is here
+			if ($ext_loaded === TRUE)
+			{
+				$base_helper = BASEPATH.'helpers/'.$helper.'.php';
 				if ( ! file_exists($base_helper))
 				{
 					show_error('Unable to load the requested file: helpers/'.$helper.'.php');
 				}
 
-				include_once($ext_helper);
 				include_once($base_helper);
-
 				$this->_ci_helpers[$helper] = TRUE;
-				log_message('debug', 'Helper loaded: '.$helper);
+				log_message('info', 'Helper loaded: '.$helper);
 				continue;
 			}
 
-			// Try to load the helper
+			// No extensions found ... try loading regular helpers and/or overrides
 			foreach ($this->_ci_helper_paths as $path)
 			{
 				if (file_exists($path.'helpers/'.$helper.'.php'))
@@ -527,7 +633,7 @@ class CI_Loader {
 					include_once($path.'helpers/'.$helper.'.php');
 
 					$this->_ci_helpers[$helper] = TRUE;
-					log_message('debug', 'Helper loaded: '.$helper);
+					log_message('info', 'Helper loaded: '.$helper);
 					break;
 				}
 			}
@@ -538,6 +644,8 @@ class CI_Loader {
 				show_error('Unable to load the requested file: helpers/'.$helper.'.php');
 			}
 		}
+
+		return $this;
 	}
 
 	// --------------------------------------------------------------------
@@ -545,82 +653,96 @@ class CI_Loader {
 	/**
 	 * Load Helpers
 	 *
-	 * This is simply an alias to the above function in case the
-	 * user has written the plural form of this function.
+	 * An alias for the helper() method in case the developer has
+	 * written the plural form of it.
 	 *
-	 * @param	array
-	 * @return	void
+	 * @uses	CI_Loader::helper()
+	 * @param	string|string[]	$helpers	Helper name(s)
+	 * @return	object
 	 */
 	public function helpers($helpers = array())
 	{
-		$this->helper($helpers);
+		return $this->helper($helpers);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Loads a language file
+	 * Language Loader
 	 *
-	 * @param	array
-	 * @param	string
-	 * @return	void
+	 * Loads language files.
+	 *
+	 * @param	string|string[]	$files	List of language file names to load
+	 * @param	string		Language name
+	 * @return	object
 	 */
-	public function language($file = array(), $lang = '')
+	public function language($files, $lang = '')
 	{
-		$CI =& get_instance();
-
-		if ( ! is_array($file))
-		{
-			$file = array($file);
-		}
-
-		foreach ($file as $langfile)
-		{
-			$CI->lang->load($langfile, $lang);
-		}
+		get_instance()->lang->load($files, $lang);
+		return $this;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Loads a config file
+	 * Config Loader
 	 *
-	 * @param	string
-	 * @param	bool
-	 * @param 	bool
-	 * @return	void
+	 * Loads a config file (an alias for CI_Config::load()).
+	 *
+	 * @uses	CI_Config::load()
+	 * @param	string	$file			Configuration file name
+	 * @param	bool	$use_sections		Whether configuration values should be loaded into their own section
+	 * @param	bool	$fail_gracefully	Whether to just return FALSE or display an error message
+	 * @return	bool	TRUE if the file was loaded correctly or FALSE on failure
 	 */
-	public function config($file = '', $use_sections = FALSE, $fail_gracefully = FALSE)
+	public function config($file, $use_sections = FALSE, $fail_gracefully = FALSE)
 	{
-		$CI =& get_instance();
-		$CI->config->load($file, $use_sections, $fail_gracefully);
+		return get_instance()->config->load($file, $use_sections, $fail_gracefully);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Driver
+	 * Driver Loader
 	 *
-	 * Loads a driver library
+	 * Loads a driver library.
 	 *
-	 * @param	string	the name of the class
-	 * @param	mixed	the optional parameters
-	 * @param	string	an optional object name
-	 * @return	void
+	 * @param	string|string[]	$library	Driver name(s)
+	 * @param	array		$params		Optional parameters to pass to the driver
+	 * @param	string		$object_name	An optional object name to assign to
+	 *
+	 * @return	object|bool	Object or FALSE on failure if $library is a string
+	 *				and $object_name is set. CI_Loader instance otherwise.
 	 */
-	public function driver($library = '', $params = NULL, $object_name = NULL)
+	public function driver($library, $params = NULL, $object_name = NULL)
 	{
-		if ( ! class_exists('CI_Driver_Library'))
+		if (is_array($library))
 		{
-			// we aren't instantiating an object here, that'll be done by the Library itself
-			require BASEPATH.'libraries/Driver.php';
-		}
+			foreach ($library as $key => $value)
+			{
+				if (is_int($key))
+				{
+					$this->driver($value, $params);
+				}
+				else
+				{
+					$this->driver($key, $params, $value);
+				}
+			}
 
-		if ($library == '')
+			return $this;
+		}
+		elseif (empty($library))
 		{
 			return FALSE;
 		}
 
+		if ( ! class_exists('CI_Driver_Library', FALSE))
+		{
+			// We aren't instantiating an object here, just making the base class available
+			require BASEPATH.'libraries/Driver.php';
+		}
+
 		// We can save the loader some time since Drivers will *always* be in a subfolder,
 		// and typically identically named to the library
 		if ( ! strpos($library, '/'))
@@ -636,13 +758,19 @@ class CI_Loader {
 	/**
 	 * Add Package Path
 	 *
-	 * Prepends a parent path to the library, model, helper, and config path arrays
+	 * Prepends a parent path to the library, model, helper and config
+	 * path arrays.
 	 *
-	 * @param	string
-	 * @param 	boolean
-	 * @return	void
+	 * @see	CI_Loader::$_ci_library_paths
+	 * @see	CI_Loader::$_ci_model_paths
+	 * @see CI_Loader::$_ci_helper_paths
+	 * @see CI_Config::$_config_paths
+	 *
+	 * @param	string	$path		Path to add
+	 * @param 	bool	$view_cascade	(default: TRUE)
+	 * @return	object
 	 */
-	public function add_package_path($path, $view_cascade=TRUE)
+	public function add_package_path($path, $view_cascade = TRUE)
 	{
 		$path = rtrim($path, '/').'/';
 
@@ -654,7 +782,9 @@ class CI_Loader {
 
 		// Add config file path
 		$config =& $this->_ci_get_component('config');
-		array_unshift($config->_config_paths, $path);
+		$config->_config_paths[] = $path;
+
+		return $this;
 	}
 
 	// --------------------------------------------------------------------
@@ -662,14 +792,14 @@ class CI_Loader {
 	/**
 	 * Get Package Paths
 	 *
-	 * Return a list of all package paths, by default it will ignore BASEPATH.
+	 * Return a list of all package paths.
 	 *
-	 * @param	string
-	 * @return	void
+	 * @param	bool	$include_base	Whether to include BASEPATH (default: FALSE)
+	 * @return	array
 	 */
 	public function get_package_paths($include_base = FALSE)
 	{
-		return $include_base === TRUE ? $this->_ci_library_paths : $this->_ci_model_paths;
+		return ($include_base === TRUE) ? $this->_ci_library_paths : $this->_ci_model_paths;
 	}
 
 	// --------------------------------------------------------------------
@@ -677,24 +807,24 @@ class CI_Loader {
 	/**
 	 * Remove Package Path
 	 *
-	 * Remove a path from the library, model, and helper path arrays if it exists
-	 * If no path is provided, the most recently added path is removed.
+	 * Remove a path from the library, model, helper and/or config
+	 * path arrays if it exists. If no path is provided, the most recently
+	 * added path will be removed removed.
 	 *
-	 * @param	type
-	 * @param 	bool
-	 * @return	type
+	 * @param	string	$path	Path to remove
+	 * @return	object
 	 */
-	public function remove_package_path($path = '', $remove_config_path = TRUE)
+	public function remove_package_path($path = '')
 	{
 		$config =& $this->_ci_get_component('config');
 
-		if ($path == '')
+		if ($path === '')
 		{
-			$void = array_shift($this->_ci_library_paths);
-			$void = array_shift($this->_ci_model_paths);
-			$void = array_shift($this->_ci_helper_paths);
-			$void = array_shift($this->_ci_view_paths);
-			$void = array_shift($config->_config_paths);
+			array_shift($this->_ci_library_paths);
+			array_shift($this->_ci_model_paths);
+			array_shift($this->_ci_helper_paths);
+			array_shift($this->_ci_view_paths);
+			array_pop($config->_config_paths);
 		}
 		else
 		{
@@ -724,32 +854,37 @@ class CI_Loader {
 		$this->_ci_model_paths = array_unique(array_merge($this->_ci_model_paths, array(APPPATH)));
 		$this->_ci_view_paths = array_merge($this->_ci_view_paths, array(APPPATH.'views/' => TRUE));
 		$config->_config_paths = array_unique(array_merge($config->_config_paths, array(APPPATH)));
+
+		return $this;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Loader
+	 * Internal CI Data Loader
+	 *
+	 * Used to load views and files.
 	 *
-	 * 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
+	 * variables made available to view files.
 	 *
-	 * @param	array
-	 * @return	void
+	 * @used-by	CI_Loader::view()
+	 * @used-by	CI_Loader::file()
+	 * @param	array	$_ci_data	Data to load
+	 * @return	object
 	 */
 	protected function _ci_load($_ci_data)
 	{
 		// Set the default data variables
 		foreach (array('_ci_view', '_ci_vars', '_ci_path', '_ci_return') as $_ci_val)
 		{
-			$$_ci_val = ( ! isset($_ci_data[$_ci_val])) ? FALSE : $_ci_data[$_ci_val];
+			$$_ci_val = isset($_ci_data[$_ci_val]) ? $_ci_data[$_ci_val] : FALSE;
 		}
 
 		$file_exists = FALSE;
 
 		// Set the path to the requested file
-		if ($_ci_path != '')
+		if (is_string($_ci_path) && $_ci_path !== '')
 		{
 			$_ci_x = explode('/', $_ci_path);
 			$_ci_file = end($_ci_x);
@@ -757,13 +892,13 @@ class CI_Loader {
 		else
 		{
 			$_ci_ext = pathinfo($_ci_view, PATHINFO_EXTENSION);
-			$_ci_file = ($_ci_ext == '') ? $_ci_view.'.php' : $_ci_view;
+			$_ci_file = ($_ci_ext === '') ? $_ci_view.'.php' : $_ci_view;
 
-			foreach ($this->_ci_view_paths as $view_file => $cascade)
+			foreach ($this->_ci_view_paths as $_ci_view_file => $cascade)
 			{
-				if (file_exists($view_file.$_ci_file))
+				if (file_exists($_ci_view_file.$_ci_file))
 				{
-					$_ci_path = $view_file.$_ci_file;
+					$_ci_path = $_ci_view_file.$_ci_file;
 					$file_exists = TRUE;
 					break;
 				}
@@ -782,7 +917,6 @@ class CI_Loader {
 
 		// This allows anything loaded using $this->load (views, files, etc.)
 		// to become accessible from within the Controller and Model functions.
-
 		$_ci_CI =& get_instance();
 		foreach (get_object_vars($_ci_CI) as $_ci_key => $_ci_var)
 		{
@@ -795,15 +929,12 @@ class CI_Loader {
 		/*
 		 * Extract and cache variables
 		 *
-		 * You can either set variables using the dedicated $this->load_vars()
+		 * 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, $_ci_vars);
-		}
+		empty($_ci_vars) OR $this->_ci_cached_vars = array_merge($this->_ci_cached_vars, $_ci_vars);
 		extract($this->_ci_cached_vars);
 
 		/*
@@ -811,29 +942,27 @@ class CI_Loader {
 		 *
 		 * 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.
+		 * 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)
+		if ( ! is_php('5.4') && ! ini_get('short_open_tag') && config_item('rewrite_short_tags') === TRUE)
 		{
-			echo eval('?>'.preg_replace("/;*\s*\?>/", "; ?>", str_replace('<?=', '<?php echo ', file_get_contents($_ci_path))));
+			echo eval('?>'.preg_replace('/;*\s*\?>/', '; ?>', str_replace('<?=', '<?php echo ', file_get_contents($_ci_path))));
 		}
 		else
 		{
 			include($_ci_path); // include() vs include_once() allows for multiple views with the same name
 		}
 
-		log_message('debug', 'File loaded: '.$_ci_path);
+		log_message('info', 'File loaded: '.$_ci_path);
 
 		// Return the file data if requested
 		if ($_ci_return === TRUE)
@@ -851,7 +980,6 @@ class CI_Loader {
 		 * 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)
 		{
@@ -862,21 +990,24 @@ class CI_Loader {
 			$_ci_CI->output->append_output(ob_get_contents());
 			@ob_end_clean();
 		}
+
+		return $this;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Load class
+	 * Internal CI Library Loader
 	 *
-	 * This function loads the requested class.
+	 * @used-by	CI_Loader::library()
+	 * @uses	CI_Loader::_ci_init_library()
 	 *
-	 * @param	string	the item that is being loaded
-	 * @param	mixed	any additional parameters
-	 * @param	string	an optional object name
+	 * @param	string	$class		Class name to load
+	 * @param	mixed	$params		Optional parameters to pass to the class constructor
+	 * @param	string	$object_name	Optional object name to assign to
 	 * @return	void
 	 */
-	protected function _ci_load_class($class, $params = NULL, $object_name = NULL)
+	protected function _ci_load_library($class, $params = NULL, $object_name = NULL)
 	{
 		// Get the class name, and while we're at it trim any slashes.
 		// The directory path can be included as part of the class name,
@@ -885,128 +1016,184 @@ class CI_Loader {
 
 		// Was the path included with the class name?
 		// We look for a slash to determine this
-		$subdir = '';
 		if (($last_slash = strrpos($class, '/')) !== FALSE)
 		{
 			// Extract the path
-			$subdir = substr($class, 0, $last_slash + 1);
+			$subdir = substr($class, 0, ++$last_slash);
 
 			// Get the filename from the path
-			$class = substr($class, $last_slash + 1);
+			$class = substr($class, $last_slash);
+		}
+		else
+		{
+			$subdir = '';
 		}
 
-		// We'll test for both lowercase and capitalized versions of the file name
-		foreach (array(ucfirst($class), strtolower($class)) as $class)
+		$class = ucfirst($class);
+
+		// Is this a stock library? There are a few special conditions if so ...
+		if (file_exists(BASEPATH.'libraries/'.$subdir.$class.'.php'))
 		{
-			$subclass = APPPATH.'libraries/'.$subdir.config_item('subclass_prefix').$class.'.php';
+			return $this->_ci_load_stock_library($class, $subdir, $params, $object_name);
+		}
 
-			// Is this a class extension request?
-			if (file_exists($subclass))
+		// Let's search for the requested library file and load it.
+		foreach ($this->_ci_library_paths as $path)
+		{
+			// BASEPATH has already been checked for
+			if ($path === BASEPATH)
 			{
-				$baseclass = BASEPATH.'libraries/'.ucfirst($class).'.php';
+				continue;
+			}
 
-				if ( ! file_exists($baseclass))
-				{
-					log_message('error', "Unable to load the requested class: ".$class);
-					show_error("Unable to load the requested class: ".$class);
-				}
+			$filepath = $path.'libraries/'.$subdir.$class.'.php';
 
-				// Safety:  Was the class already loaded by a previous call?
-				if (in_array($subclass, $this->_ci_loaded_files))
+			// Safety: Was the class already loaded by a previous call?
+			if (class_exists($class, FALSE))
+			{
+				// Before we deem this to be a duplicate request, let's see
+				// if a custom object name is being supplied. If so, we'll
+				// return a new instance of the object
+				if ($object_name !== NULL)
 				{
-					// Before we deem this to be a duplicate request, let's see
-					// if a custom object name is being supplied.  If so, we'll
-					// return a new instance of the object
-					if ( ! is_null($object_name))
+					$CI =& get_instance();
+					if ( ! isset($CI->$object_name))
 					{
-						$CI =& get_instance();
-						if ( ! isset($CI->$object_name))
-						{
-							return $this->_ci_init_class($class, config_item('subclass_prefix'), $params, $object_name);
-						}
+						return $this->_ci_init_library($class, '', $params, $object_name);
 					}
-
-					$is_duplicate = TRUE;
-					log_message('debug', $class." class already loaded. Second attempt ignored.");
-					return;
 				}
 
-				include_once($baseclass);
-				include_once($subclass);
-				$this->_ci_loaded_files[] = $subclass;
-
-				return $this->_ci_init_class($class, config_item('subclass_prefix'), $params, $object_name);
+				log_message('debug', $class.' class already loaded. Second attempt ignored.');
+				return;
+			}
+			// Does the file exist? No? Bummer...
+			elseif ( ! file_exists($filepath))
+			{
+				continue;
 			}
 
-			// Lets search for the requested library file and load it.
-			$is_duplicate = FALSE;
-			foreach ($this->_ci_library_paths as $path)
+			include_once($filepath);
+			return $this->_ci_init_library($class, '', $params, $object_name);
+		}
+
+		// One last attempt. Maybe the library is in a subdirectory, but it wasn't specified?
+		if ($subdir === '')
+		{
+			return $this->_ci_load_library($class.'/'.$class, $params, $object_name);
+		}
+
+		// If we got this far we were unable to find the requested class.
+		log_message('error', 'Unable to load the requested class: '.$class);
+		show_error('Unable to load the requested class: '.$class);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Internal CI Stock Library Loader
+	 *
+	 * @used-by	CI_Loader::_ci_load_library()
+	 * @uses	CI_Loader::_ci_init_library()
+	 *
+	 * @param	string	$library_name	Library name to load
+	 * @param	string	$file_path	Path to the library filename, relative to libraries/
+	 * @param	mixed	$params		Optional parameters to pass to the class constructor
+	 * @param	string	$object_name	Optional object name to assign to
+	 * @return	void
+	 */
+	protected function _ci_load_stock_library($library_name, $file_path, $params, $object_name)
+	{
+		$prefix = 'CI_';
+
+		if (class_exists($prefix.$library_name, FALSE))
+		{
+			if (class_exists(config_item('subclass_prefix').$library_name, FALSE))
 			{
-				$filepath = $path.'libraries/'.$subdir.$class.'.php';
+				$prefix = config_item('subclass_prefix');
+			}
 
-				// Does the file exist?  No?  Bummer...
-				if ( ! file_exists($filepath))
+			// Before we deem this to be a duplicate request, let's see
+			// if a custom object name is being supplied. If so, we'll
+			// return a new instance of the object
+			if ($object_name !== NULL)
+			{
+				$CI =& get_instance();
+				if ( ! isset($CI->$object_name))
 				{
-					continue;
+					return $this->_ci_init_library($library_name, $prefix, $params, $object_name);
 				}
+			}
 
-				// Safety:  Was the class already loaded by a previous call?
-				if (in_array($filepath, $this->_ci_loaded_files))
-				{
-					// Before we deem this to be a duplicate request, let's see
-					// if a custom object name is being supplied.  If so, we'll
-					// return a new instance of the object
-					if ( ! is_null($object_name))
-					{
-						$CI =& get_instance();
-						if ( ! isset($CI->$object_name))
-						{
-							return $this->_ci_init_class($class, '', $params, $object_name);
-						}
-					}
+			log_message('debug', $library_name.' class already loaded. Second attempt ignored.');
+			return;
+		}
 
-					$is_duplicate = TRUE;
-					log_message('debug', $class." class already loaded. Second attempt ignored.");
-					return;
-				}
+		$paths = $this->_ci_library_paths;
+		array_pop($paths); // BASEPATH
+		array_pop($paths); // APPPATH (needs to be the first path checked)
+		array_unshift($paths, APPPATH);
 
-				include_once($filepath);
-				$this->_ci_loaded_files[] = $filepath;
-				return $this->_ci_init_class($class, '', $params, $object_name);
+		foreach ($paths as $path)
+		{
+			if (file_exists($path = $path.'libraries/'.$file_path.$library_name.'.php'))
+			{
+				// Override
+				include_once($path);
+				if (class_exists($prefix.$library_name, FALSE))
+				{
+					return $this->_ci_init_library($library_name, $prefix, $params, $object_name);
+				}
+				else
+				{
+					log_message('debug', $path.' exists, but does not declare '.$prefix.$library_name);
+				}
 			}
+		}
 
-		} // END FOREACH
+		include_once(BASEPATH.'libraries/'.$file_path.$library_name.'.php');
 
-		// One last attempt.  Maybe the library is in a subdirectory, but it wasn't specified?
-		if ($subdir == '')
+		// Check for extensions
+		$subclass = config_item('subclass_prefix').$library_name;
+		foreach ($paths as $path)
 		{
-			$path = strtolower($class).'/'.$class;
-			return $this->_ci_load_class($path, $params);
+			if (file_exists($path = $path.'libraries/'.$file_path.$subclass.'.php'))
+			{
+				include_once($path);
+				if (class_exists($subclass, FALSE))
+				{
+					$prefix = config_item('subclass_prefix');
+					break;
+				}
+				else
+				{
+					log_message('debug', $path.' exists, but does not declare '.$subclass);
+				}
+			}
 		}
 
-		// 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);
-		}
+		return $this->_ci_init_library($library_name, $prefix, $params, $object_name);
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Instantiates a class
+	 * Internal CI Library Instantiator
+	 *
+	 * @used-by	CI_Loader::_ci_load_stock_library()
+	 * @used-by	CI_Loader::_ci_load_library()
 	 *
-	 * @param	string
-	 * @param	string
-	 * @param	bool
-	 * @param	string	an optional object name
-	 * @return	null
+	 * @param	string		$class		Class name
+	 * @param	string		$prefix		Class name prefix
+	 * @param	array|null|bool	$config		Optional configuration to pass to the class constructor:
+	 *						FALSE to skip;
+	 *						NULL to search in config paths;
+	 *						array containing configuration data
+	 * @param	string		$object_name	Optional object name to assign to
+	 * @return	void
 	 */
-	protected function _ci_init_class($class, $prefix = '', $config = FALSE, $object_name = NULL)
+	protected function _ci_init_library($class, $prefix, $config = FALSE, $object_name = NULL)
 	{
-		// Is there an associated config file for this class?  Note: these should always be lowercase
+		// Is there an associated config file for this class? Note: these should always be lowercase
 		if ($config === NULL)
 		{
 			// Fetch the config paths containing any package paths
@@ -1014,117 +1201,111 @@ class CI_Loader {
 
 			if (is_array($config_component->_config_paths))
 			{
-				// Break on the first found file, thus package files
-				// are not overridden by default paths
+				$found = FALSE;
 				foreach ($config_component->_config_paths as $path)
 				{
 					// We test for both uppercase and lowercase, for servers that
-					// are case-sensitive with regard to file names. Check for environment
-					// first, global next
-					if (defined('ENVIRONMENT') AND file_exists($path .'config/'.ENVIRONMENT.'/'.strtolower($class).'.php'))
+					// are case-sensitive with regard to file names. Load global first,
+					// override with environment next
+					if (file_exists($path.'config/'.strtolower($class).'.php'))
 					{
-						include($path .'config/'.ENVIRONMENT.'/'.strtolower($class).'.php');
-						break;
+						include($path.'config/'.strtolower($class).'.php');
+						$found = TRUE;
 					}
-					elseif (defined('ENVIRONMENT') AND file_exists($path .'config/'.ENVIRONMENT.'/'.ucfirst(strtolower($class)).'.php'))
+					elseif (file_exists($path.'config/'.ucfirst(strtolower($class)).'.php'))
 					{
-						include($path .'config/'.ENVIRONMENT.'/'.ucfirst(strtolower($class)).'.php');
-						break;
+						include($path.'config/'.ucfirst(strtolower($class)).'.php');
+						$found = TRUE;
 					}
-					elseif (file_exists($path .'config/'.strtolower($class).'.php'))
+
+					if (file_exists($path.'config/'.ENVIRONMENT.'/'.strtolower($class).'.php'))
 					{
-						include($path .'config/'.strtolower($class).'.php');
-						break;
+						include($path.'config/'.ENVIRONMENT.'/'.strtolower($class).'.php');
+						$found = TRUE;
 					}
-					elseif (file_exists($path .'config/'.ucfirst(strtolower($class)).'.php'))
+					elseif (file_exists($path.'config/'.ENVIRONMENT.'/'.ucfirst(strtolower($class)).'.php'))
+					{
+						include($path.'config/'.ENVIRONMENT.'/'.ucfirst(strtolower($class)).'.php');
+						$found = TRUE;
+					}
+
+					// Break on the first found configuration, thus package
+					// files are not overridden by default paths
+					if ($found === TRUE)
 					{
-						include($path .'config/'.ucfirst(strtolower($class)).'.php');
 						break;
 					}
 				}
 			}
 		}
 
-		if ($prefix == '')
-		{
-			if (class_exists('CI_'.$class))
-			{
-				$name = 'CI_'.$class;
-			}
-			elseif (class_exists(config_item('subclass_prefix').$class))
-			{
-				$name = config_item('subclass_prefix').$class;
-			}
-			else
-			{
-				$name = $class;
-			}
-		}
-		else
-		{
-			$name = $prefix.$class;
-		}
+		$class_name = $prefix.$class;
 
 		// Is the class name valid?
-		if ( ! class_exists($name))
+		if ( ! class_exists($class_name, FALSE))
 		{
-			log_message('error', "Non-existent class: ".$name);
-			show_error("Non-existent class: ".$class);
+			log_message('error', 'Non-existent class: '.$class_name);
+			show_error('Non-existent class: '.$class_name);
 		}
 
 		// Set the variable name we will assign the class to
-		// Was a custom class name supplied?  If so we'll use it
-		$class = strtolower($class);
-
-		if (is_null($object_name))
+		// Was a custom class name supplied? If so we'll use it
+		if (empty($object_name))
 		{
-			$classvar = ( ! isset($this->_ci_varmap[$class])) ? $class : $this->_ci_varmap[$class];
+			$object_name = strtolower($class);
+			if (isset($this->_ci_varmap[$object_name]))
+			{
+				$object_name = $this->_ci_varmap[$object_name];
+			}
 		}
-		else
+
+		// Don't overwrite existing properties
+		$CI =& get_instance();
+		if (isset($CI->$object_name))
 		{
-			$classvar = $object_name;
+			if ($CI->$object_name instanceof $class_name)
+			{
+				log_message('debug', $class_name." has already been instantiated as '".$object_name."'. Second attempt aborted.");
+				return;
+			}
+
+			show_error("Resource '".$object_name."' already exists and is not a ".$class_name." instance.");
 		}
 
 		// Save the class name and object name
-		$this->_ci_classes[$class] = $classvar;
+		$this->_ci_classes[$object_name] = $class;
 
 		// Instantiate the class
-		$CI =& get_instance();
-		if ($config !== NULL)
-		{
-			$CI->$classvar = new $name($config);
-		}
-		else
-		{
-			$CI->$classvar = new $name;
-		}
+		$CI->$object_name = isset($config)
+			? new $class_name($config)
+			: new $class_name();
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Autoloader
+	 * CI Autoloader
 	 *
-	 * The config/autoload.php file contains an array that permits sub-systems,
-	 * libraries, and helpers to be loaded automatically.
+	 * Loads component listed in the config/autoload.php file.
 	 *
-	 * @param	array
+	 * @used-by	CI_Loader::initialize()
 	 * @return	void
 	 */
-	private function _ci_autoloader()
+	protected function _ci_autoloader()
 	{
-		if (defined('ENVIRONMENT') AND file_exists(APPPATH.'config/'.ENVIRONMENT.'/autoload.php'))
+		if (file_exists(APPPATH.'config/autoload.php'))
 		{
-			include(APPPATH.'config/'.ENVIRONMENT.'/autoload.php');
+			include(APPPATH.'config/autoload.php');
 		}
-		else
+
+		if (file_exists(APPPATH.'config/'.ENVIRONMENT.'/autoload.php'))
 		{
-			include(APPPATH.'config/autoload.php');
+			include(APPPATH.'config/'.ENVIRONMENT.'/autoload.php');
 		}
 
 		if ( ! isset($autoload))
 		{
-			return FALSE;
+			return;
 		}
 
 		// Autoload packages
@@ -1139,31 +1320,29 @@ class CI_Loader {
 		// Load any custom config file
 		if (count($autoload['config']) > 0)
 		{
-			$CI =& get_instance();
-			foreach ($autoload['config'] as $key => $val)
+			foreach ($autoload['config'] as $val)
 			{
-				$CI->config->load($val);
+				$this->config($val);
 			}
 		}
 
 		// Autoload helpers and languages
 		foreach (array('helper', 'language') as $type)
 		{
-			if (isset($autoload[$type]) AND count($autoload[$type]) > 0)
+			if (isset($autoload[$type]) && count($autoload[$type]) > 0)
 			{
 				$this->$type($autoload[$type]);
 			}
 		}
 
-		// A little tweak to remain backward compatible
-		// The $autoload['core'] item was deprecated
-		if ( ! isset($autoload['libraries']) AND isset($autoload['core']))
+		// Autoload drivers
+		if (isset($autoload['drivers']))
 		{
-			$autoload['libraries'] = $autoload['core'];
+			$this->driver($autoload['drivers']);
 		}
 
 		// Load libraries
-		if (isset($autoload['libraries']) AND count($autoload['libraries']) > 0)
+		if (isset($autoload['libraries']) && count($autoload['libraries']) > 0)
 		{
 			// Load the database driver.
 			if (in_array('database', $autoload['libraries']))
@@ -1173,10 +1352,7 @@ class CI_Loader {
 			}
 
 			// Load all other libraries
-			foreach ($autoload['libraries'] as $item)
-			{
-				$this->library($item);
-			}
+			$this->library($autoload['libraries']);
 		}
 
 		// Autoload models
@@ -1189,24 +1365,42 @@ class CI_Loader {
 	// --------------------------------------------------------------------
 
 	/**
-	 * Object to Array
+	 * Prepare variables for _ci_vars, to be later extract()-ed inside views
 	 *
-	 * Takes an object as input and converts the class variables to array key/vals
+	 * Converts objects to associative arrays and filters-out internal
+	 * variable names (i.e. keys prefixed with '_ci_').
 	 *
-	 * @param	object
+	 * @param	mixed	$vars
 	 * @return	array
 	 */
-	protected function _ci_object_to_array($object)
+	protected function _ci_prepare_view_vars($vars)
 	{
-		return (is_object($object)) ? get_object_vars($object) : $object;
+		if ( ! is_array($vars))
+		{
+			$vars = is_object($vars)
+				? get_object_vars($vars)
+				: array();
+		}
+
+		foreach (array_keys($vars) as $key)
+		{
+			if (strncmp($key, '_ci_', 4) === 0)
+			{
+				unset($vars[$key]);
+			}
+		}
+
+		return $vars;
 	}
 
 	// --------------------------------------------------------------------
 
 	/**
-	 * Get a reference to a specific library or model
+	 * CI Component getter
+	 *
+	 * Get a reference to a specific library or model.
 	 *
-	 * @param 	string
+	 * @param 	string	$component	Component name
 	 * @return	bool
 	 */
 	protected function &_ci_get_component($component)
@@ -1214,35 +1408,4 @@ class CI_Loader {
 		$CI =& get_instance();
 		return $CI->$component;
 	}
-
-	// --------------------------------------------------------------------
-
-	/**
-	 * Prep filename
-	 *
-	 * This function preps the name of various items to make loading them more reliable.
-	 *
-	 * @param	mixed
-	 * @param 	string
-	 * @return	array
-	 */
-	protected function _ci_prep_filename($filename, $extension)
-	{
-		if ( ! is_array($filename))
-		{
-			return array(strtolower(str_replace('.php', '', str_replace($extension, '', $filename)).$extension));
-		}
-		else
-		{
-			foreach ($filename as $key => $val)
-			{
-				$filename[$key] = strtolower(str_replace('.php', '', str_replace($extension, '', $val)).$extension);
-			}
-
-			return $filename;
-		}
-	}
 }
-
-/* End of file Loader.php */
-/* Location: ./system/core/Loader.php */
\ No newline at end of file