CI框架装载器Loader.php源码分析

/
  Loader Class
 
  用户加载views和files，常见的函数有model(),view(),library(),helper()
 
  Controller的好助手，$this->load =& load_class('Loader', 'core');，加载了loader，Controller就无比强大了
 /
class CI_Loader {
 protected $_ci_ob_level;
 protected $_ci_view_paths  = array();
 protected $_ci_library_paths = array();
 protected $_ci_model_paths  = array();
 protected $_ci_helper_paths  = array();
 protected $_base_classes  = array(); // Set by the controller class
 protected $_ci_cached_vars  = array();
 protected $_ci_classes   = array();
 protected $_ci_loaded_files  = array();
 
 protected $_ci_models   = array();
 protected $_ci_helpers   = array();
 protected $_ci_varmap   = array('unit_test' => 'unit',
           'user_agent' => 'agent');
 public function __construct()
 {      
                //获取缓冲嵌套级别
  $this->_ci_ob_level  = ob_get_level();
  //library路径
                $this->_ci_library_paths = array(APPPATH, BASEPATH);
                //helper路径
  $this->_ci_helper_paths = array(APPPATH, BASEPATH);
                //model路径
  $this->_ci_model_paths = array(APPPATH);
                //view路径
  $this->_ci_view_paths = array(APPPATH.'views/' => TRUE);
  log_message('debug', "Loader Class Initialized");
 }
 // --------------------------------------------------------------------
 /
  初始化Loader
 
  /
 public function initialize()
 {
  $this->_ci_classes = array();
  $this->_ci_loaded_files = array();
  $this->_ci_models = array();
                //将is_loaded（mon中记录加载核心类函数）加载的核心类交给_base_classes
  $this->_base_classes =& is_loaded();
                //加载autoload.php配置中文件
  $this->_ci_autoloader();
  return $this;
 }
 // --------------------------------------------------------------------
 /
  检测类是否加载
  /
 public function is_loaded($class)
 {
  if (isset($this->_ci_classes[$class]))
  {
   return $this->_ci_classes[$class];
  }
  return FALSE;
 }
 // --------------------------------------------------------------------
 /
  加载Class
  /
 public function library($library = '', $params = NULL, $object_name = NULL)
 {
  if (is_array($library))
  {
   foreach ($library as $class)
   {
    $this->library($class, $params);
   }
   return;
  }
                //如果$library为空或者已经加载。。。
  if ($library == '' OR isset($this->_base_classes[$library]))
  {
   return FALSE;
  }
  if ( ! is_null($params) && ! is_array($params))
  {
   $params = NULL;
  }
  $this->_ci_load_class($library, $params, $object_name);
 }
 // --------------------------------------------------------------------
 /
  加载和实例化model
  /
 public function model($model, $name = '', $db_conn = FALSE)
 {
                //CI支持数组加载多个model
  if (is_array($model))
  {
   foreach ($model as $babe)
   {
    $this->model($babe);
   }
   return;
  }
  if ($model == '')
  {
   return;
  }
  $path = '';
  // 是否存在子目录
  if (($last_slash = strrpos($model, '/')) !== FALSE)
  {
   // The path is in front of the last slash
   $path = substr($model, 0, $last_slash + 1);
   // And the model name behind it
   $model = substr($model, $last_slash + 1);
  }
  if ($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); //model文件名全小写
  foreach ($this->_ci_model_paths as $mod_path)
  {
   if ( ! file_exists($mod_path.'models/'.$path.$model.'.php'))
   {
    continue;
   }
   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('CI_Model'))
   {
    load_class('Model', 'core');
   }
   require_once($mod_path.'models/'.$path.$model.'.php');
   $model = ucfirst($model);
   $CI->$name = new $model();
                        //保存在Loader::_ci_models中，以后可以用它来判断某个model是否已经加载过。
   $this->_ci_models[] = $name;
   return;
  }
  // couldn't find the model
  show_error('Unable to locate the model you have specified: '.$model);
 }
 // --------------------------------------------------------------------
 /
  数据库Loader
  /
 public function database($params = '', $return = FALSE, $active_record = NULL)
 {
  // Grab the super object
  $CI =& get_instance();
  // 是否需要加载db
  if (class_exists('CI_DB') AND $return == FALSE AND $active_record == NULL AND isset($CI->db) AND is_object($CI->db))
  {
   return FALSE;
  }
  require_once(BASEPATH.'database/DB.php');
  if ($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);
 }
 // --------------------------------------------------------------------
 /
  加载数据库工具类
  /
 public function dbutil()
 {
  if ( ! class_exists('CI_DB'))
  {
   $this->database();
  }
  $CI =& get_instance();
  // for backwards patibility, load dbfe so we can extend dbutils off it
  // this use is deprecated and strongly discouraged
  $CI->load->dbfe();
  require_once(BASEPATH.'database/DB_utility.php');
  require_once(BASEPATH.'database/drivers/'.$CI->db->dbdriver.'/'.$CI->db->dbdriver.'_utility.php');
  $class = 'CI_DB_'.$CI->db->dbdriver.'_utility';
  $CI->dbutil = new $class();
 }
 // --------------------------------------------------------------------
 /
  Load the Database Fe Class
 
  @return string
  /
 public function dbfe()
 {
  if ( ! class_exists('CI_DB'))
  {
   $this->database();
  }
  $CI =& get_instance();
  require_once(BASEPATH.'database/DB_fe.php');
  require_once(BASEPATH.'database/drivers/'.$CI->db->dbdriver.'/'.$CI->db->dbdriver.'_fe.php');
  $class = 'CI_DB_'.$CI->db->dbdriver.'_fe';
  $CI->dbfe = new $class();
 }
 // --------------------------------------------------------------------
 /
  加载视图文件
  /
 public function view($view, $vars = array(), $return = FALSE)
 {
  return $this->_ci_load(array('_ci_view' => $view, '_ci_vars' => $this->_ci_object_to_array($vars), '_ci_return' => $return));
 }
 // --------------------------------------------------------------------
 /
  加载普通文件
  /
 public function file($path, $return = FALSE)
 {
  return $this->_ci_load(array('_ci_path' => $path, '_ci_return' => $return));
 }
 // --------------------------------------------------------------------
 /
  设置变量
 
  Once variables are set they bee available within
  the controller class and its "view" files.
 
  /
 public function vars($vars = array(), $val = '')
 {
  if ($val != '' AND is_string($vars))
  {
   $vars = array($vars => $val);
  }
  $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] = $val;
   }
  }
 }
 // --------------------------------------------------------------------
 /
  检查并获取变量
  /
 public function get_var($key)
 {
  return isset($this->_ci_cached_vars[$key]) ? $this->_ci_cached_vars[$key] : NULL;
 }
 // --------------------------------------------------------------------
 /
  加载helper
  /
 public function helper($helpers = array())
 {
  foreach ($this->_ci_prep_filename($helpers, '_helper') as $helper)
  {
   if (isset($this->_ci_helpers[$helper]))
   {
    continue;
   }
   $ext_helper = APPPATH.'helpers/'.config_item('subclass_prefix').$helper.'.php';
   // 如果是扩展helper的话
   if (file_exists($ext_helper))
   {
    $base_helper = BASEPATH.'helpers/'.$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: '.$helper);
    continue;
   }
   // 如果不是扩展helper，helper路径中加载helper
   foreach ($this->_ci_helper_paths as $path)
   {
    if (file_exists($path.'helpers/'.$helper.'.php'))
    {
     include_once($path.'helpers/'.$helper.'.php');
     $this->_ci_helpers[$helper] = TRUE;
     log_message('debug', 'Helper loaded: '.$helper);
     break;
    }
   }
   // 如果该helper还没加载成功的话，说明加载helper失败
   if ( ! isset($this->_ci_helpers[$helper]))
   {
    show_error('Unable to load the requested file: helpers/'.$helper.'.php');
   }
  }
 }
 // --------------------------------------------------------------------
 /
  可以看到helpers调用也是上面的helper,只是helpers的别名而已
  /
 public function helpers($helpers = array())
 {
  $this->helper($helpers);
 }
 // --------------------------------------------------------------------
 /
  加载language文件
  /
 public function language($file = array(), $lang = '')
 {
  $CI =& get_instance();
  if ( ! is_array($file))
  {
   $file = array($file);
  }
  foreach ($file as $langfile)
  {
   $CI->lang->load($langfile, $lang);
  }
 }
 // --------------------------------------------------------------------
 /
  加载配置文件
  /
 public function config($file = '', $use_sections = FALSE, $fail_gracefully = FALSE)
 {
  $CI =& get_instance();
  $CI->config->load($file, $use_sections, $fail_gracefully);
 }
 // --------------------------------------------------------------------
 /
  Driver
 
  加载 driver library
  /
 public function driver($library = '', $params = NULL, $object_name = NULL)
 {
  if ( ! class_exists('CI_Driver_Library'))
  {
   // we aren't instantiating an object here, that'll be done by the Library itself
   require BASEPATH.'libraries/Driver.php';
  }
  if ($library == '')
  {
   return FALSE;
  }
  // 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, '/'))
  {
   $library = ucfirst($library).'/'.$library;
  }
  return $this->library($library, $params, $object_name);
 }
 // --------------------------------------------------------------------
 /
  添加 Package 路径
 
  把package路径添加到库，模型，助手，配置路径
  /
 public function add_package_path($path, $view_cascade=TRUE)
 {
  $path = rtrim($path, '/').'/';
  array_unshift($this->_ci_library_paths, $path);
  array_unshift($this->_ci_model_paths, $path);
  array_unshift($this->_ci_helper_paths, $path);
  $this->_ci_view_paths = array($path.'views/' => $view_cascade) + $this->_ci_view_paths;
  $config =& $this->_ci_get_ponent('config');
  array_unshift($config->_config_paths, $path);
 }
 // --------------------------------------------------------------------
 /
  获取Package Paths，默认不包含BASEPATH
  /
 public function get_package_paths($include_base = FALSE)
 {
  return $include_base === TRUE ? $this->_ci_library_paths : $this->_ci_model_paths;
 }
 // --------------------------------------------------------------------
 /
  剔除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.
 
  /
 public function remove_package_path($path = '', $remove_config_path = TRUE)
 {
  $config =& $this->_ci_get_ponent('config');
  if ($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);
  }
  else
  {
   $path = rtrim($path, '/').'/';
   foreach (array('_ci_library_paths', '_ci_model_paths', '_ci_helper_paths') as $var)
   {
    if (($key = array_search($path, $this->{$var})) !== FALSE)
    {
     unset($this->{$var}[$key]);
    }
   }
   if (isset($this->_ci_view_paths[$path.'views/']))
   {
    unset($this->_ci_view_paths[$path.'views/']);
   }
   if (($key = array_search($path, $config->_config_paths)) !== FALSE)
   {
    unset($config->_config_paths[$key]);
   }
  }
  // 保证应用默认的路径依然存在
  $this->_ci_library_paths = array_unique(array_merge($this->_ci_library_paths, array(APPPATH, BASEPATH)));
  $this->_ci_helper_paths = array_unique(array_merge($this->_ci_helper_paths, array(APPPATH, BASEPATH)));
  $this->_ci_model_paths = array_unique(array_merge($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)));
 }
 // --------------------------------------------------------------------
 /
  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
 
  @param array
  @return void
  /
 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];
  }
  $file_exists = FALSE;
                //如果$_ci_path不为空，则说明当前要加载普通文件。Loader::file才会有path
  if ($_ci_path != '')
  {
   $_ci_x = explode('/', $_ci_path);
   $_ci_file = end($_ci_x);
  }
  else
  {
   $_ci_ext = pathinfo($_ci_view, PATHINFO_EXTENSION);
   $_ci_file = ($_ci_ext == '') ? $_ci_view.'.php' : $_ci_view;
   foreach ($this->_ci_view_paths as $view_file => $cascade)
   {
    if (file_exists($view_file.$_ci_file))
    {
     $_ci_path = $view_file.$_ci_file;
     $file_exists = TRUE;
     break;
    }
    if ( ! $cascade)
    {
     break;
    }
   }
  }
                //view文件不存在则会报错
  if ( ! $file_exists && ! file_exists($_ci_path))
  {
   show_error('Unable to load the requested file: '.$_ci_file);
  }
  // 把CI的所有属性都传递给loader，view中$this指的是loader
  $_ci_CI =& get_instance();
  foreach (get_object_vars($_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 $this->load_vars()
   function or via the second parameter of this function. We'll merge
   the two types and cache them so that views that are embedded within
   other views can have aess to these variables.
   /
  if (is_array($_ci_vars))
  {
   $this->_ci_cached_vars = array_merge($this->_ci_cached_vars, $_ci_vars);
  }
  extract($this->_ci_cached_vars);
  /
   将视图内容放到缓存区
  
   /
  ob_start();
  // 支持短标签
  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: '.$_ci_path);
  // 是否直接返回view数据
  if ($_ci_return === TRUE)
  {
   $buffer = ob_get_contents();
   @ob_end_clean();
   return $buffer;
  }
  //当前这个视图文件是被另一个视图文件通过$this->view()方法引入，即视图文件嵌入视图文件
  if (ob_get_level() > $this->_ci_ob_level + 1)
  {
   ob_end_flush();
  }
  else
  {       ////把缓冲区的内容交给Output组件并清空关闭缓冲区。
   $_ci_CI->output->append_output(ob_get_contents());
   @ob_end_clean();
  }
 }
 // --------------------------------------------------------------------
 /
  加载类
  /
 protected function _ci_load_class($class, $params = NULL, $object_name = NULL)
 {
  // 去掉.php和两端的/获取的$class就是类名或目录名+类名
  $class = str_replace('.php', '', trim($class, '/'));
  // CI允许dir/filename方式
  $subdir = '';
  if (($last_slash = strrpos($class, '/')) !== FALSE)
  {
   // 目录
   $subdir = substr($class, 0, $last_slash + 1);
   // 文件名
   $class = substr($class, $last_slash + 1);
  }
  // 允许加载的类名首字母大写或全小写
  foreach (array(ucfirst($class), strtolower($class)) as $class)
  {
   $subclass = APPPATH.'libraries/'.$subdir.config_item('subclass_prefix').$class.'.php';
   // 是否是扩展类
   if (file_exists($subclass))
   {
    $baseclass = BASEPATH.'libraries/'.ucfirst($class).'.php';
    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, $this->_ci_loaded_files))
    {
     // Before we deem this to be a duplicate request, let's see
     // if a custom object name is being supplied.  If so, we'll
     // return a new instance of the object
     if ( ! is_null($object_name))
     {
      $CI =& get_instance();
      if ( ! isset($CI->$object_name))
      {
       return $this->_ci_init_class($class, config_item('subclass_prefix'), $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;
                                //实例化类
    return $this->_ci_init_class($class, config_item('subclass_prefix'), $params, $object_name);
   }
   // 如果不是扩展，和上面类似
   $is_duplicate = FALSE;
   foreach ($this->_ci_library_paths as $path)
   {
    $filepath = $path.'libraries/'.$subdir.$class.'.php';
    // Does the file exist?  No?  Bummer...
    if ( ! file_exists($filepath))
    {
     continue;
    }
    // Safety:  Was the class already loaded by a previous call?
    if (in_array($filepath, $this->_ci_loaded_files))
    {
     // Before we deem this to be a duplicate request, let's see
     // if a custom object name is being supplied.  If so, we'll
     // return a new instance of the object
     if ( ! is_null($object_name))
     {
      $CI =& get_instance();
      if ( ! isset($CI->$object_name))
      {
       return $this->_ci_init_class($class, '', $params, $object_name);
      }
     }
     $is_duplicate = TRUE;
     log_message('debug', $class." class already loaded. Second attempt ignored.");
     return;
    }
    include_once($filepath);
    $this->_ci_loaded_files[] = $filepath;
    return $this->_ci_init_class($class, '', $params, $object_name);
   }
  } // END FOREACH
  // 如果还没有找到该class，的尝试是该class会不会在同名的子目录下
  if ($subdir == '')
  {
   $path = strtolower($class).'/'.$class;
   return $this->_ci_load_class($path, $params);
  }
  // 加载失败，报错
  if ($is_duplicate == FALSE)
  {
   log_message('error', "Unable to load the requested class: ".$class);
   show_error("Unable to load the requested class: ".$class);
  }
 }
 // --------------------------------------------------------------------
 /
  实例化已经加载的类
  /
 protected function _ci_init_class($class, $prefix = '', $config = FALSE, $object_name = NULL)
 {
  // 是否有类的配置信息
  if ($config === NULL)
  {
   // Fetch the config paths containing any package paths
   $config_ponent = $this->_ci_get_ponent('config');
   if (is_array($config_ponent->_config_paths))
   {
    // Break on the first found file, thus package files
    // are not overridden by default paths
    foreach ($config_ponent->_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($class).'.php'))
     {
      include($path .'config/'.ENVIRONMENT.'/'.strtolower($class).'.php');
      break;
     }
     elseif (defined('ENVIRONMENT') AND file_exists($path .'config/'.ENVIRONMENT.'/'.ucfirst(strtolower($class)).'.php'))
     {
      include($path .'config/'.ENVIRONMENT.'/'.ucfirst(strtolower($class)).'.php');
      break;
     }
     elseif (file_exists($path .'config/'.strtolower($class).'.php'))
     {
      include($path .'config/'.strtolower($class).'.php');
      break;
     }
     elseif (file_exists($path .'config/'.ucfirst(strtolower($class)).'.php'))
     {
      include($path .'config/'.ucfirst(strtolower($class)).'.php');
      break;
     }
    }
   }
  }
  if ($prefix == '')
  {       //system下library
   if (class_exists('CI_'.$class))
   {
    $name = 'CI_'.$class;
   }
   elseif (class_exists(config_item('subclass_prefix').$class))
   {       //扩展library
    $name = config_item('subclass_prefix').$class;
   }
   else
   {
    $name = $class;
   }
  }
  else
  {
   $name = $prefix.$class;
  }
  // Is the class name valid?
  if ( ! class_exists($name))
  {
   log_message('error', "Non-existent class: ".$name);
   show_error("Non-existent class: ".$class);
  }
  // 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))
  {
   $classvar = ( ! isset($this->_ci_varmap[$class])) ? $class : $this->_ci_varmap[$class];
  }
  else
  {
   $classvar = $object_name;
  }
  // Save the class name and object name
  $this->_ci_classes[$class] = $classvar;
  // 将初始化的类的实例给CI超级句柄
  $CI =& get_instance();
  if ($config !== NULL)
  {
   $CI->$classvar = new $name($config);
  }
  else
  {
   $CI->$classvar = new $name;
  }
 }
 // --------------------------------------------------------------------
 /
  自动加载器
        
         autoload.php配置的自动加载文件有
           | 1. Packages
            | 2. Libraries
            | 3. Helper files
            | 4. Custom config files
            | 5. Language files
            | 6. Models
  /
 private function _ci_autoloader()
 {
  if (defined('ENVIRONMENT') AND file_exists(APPPATH.'config/'.ENVIRONMENT.'/autoload.php'))
  {
   include(APPPATH.'config/'.ENVIRONMENT.'/autoload.php');
  }
  else
  {
   include(APPPATH.'config/autoload.php');
  }
  if ( ! isset($autoload))
  {
   return FALSE;
  }
  // 自动加载packages,也就是将package_path加入到library，model，helper，config
  if (isset($autoload['packages']))
  {
   foreach ($autoload['packages'] as $package_path)
   {
    $this->add_package_path($package_path);
   }
  }
  // 加载config文件
  if (count($autoload['config']) > 0)
  {
   $CI =& get_instance();
   foreach ($autoload['config'] as $key => $val)
   {
    $CI->config->load($val);
   }
  }
  // 加载helper和language
  foreach (array('helper', 'language') as $type)
  {
   if (isset($autoload[$type]) AND count($autoload[$type]) > 0)
   {
    $this->$type($autoload[$type]);
   }
  }
  // 这个好像是为了兼容以前版本的
  if ( ! isset($autoload['libraries']) AND isset($autoload['core']))
  {
   $autoload['libraries'] = $autoload['core'];
  }
  // 加载libraries
  if (isset($autoload['libraries']) AND count($autoload['libraries']) > 0)
  {
   // 加载db
   if (in_array('database', $autoload['libraries']))
   {
    $this->database();
    $autoload['libraries'] = array_diff($autoload['libraries'], array('database'));
   }
   // 加载所有其他libraries
   foreach ($autoload['libraries'] as $item)
   {
    $this->library($item);
   }
  }
  // Autoload models
  if (isset($autoload['model']))
  {
   $this->model($autoload['model']);
  }
 }
 // --------------------------------------------------------------------
 /
  返回由对象属性组成的关联数组
  /
 protected function _ci_object_to_array($object)
 {
  return (is_object($object)) ? get_object_vars($object) : $object;
 }
 // --------------------------------------------------------------------
 /
  获取CI某个组件的实例
  /
 protected function &_ci_get_ponent($ponent)
 {
  $CI =& get_instance();
  return $CI->$ponent;
 }
 // --------------------------------------------------------------------
 /
  处理文件名，这个函数主要是返回正确文件名
  /
 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;
  }
 }
}