CodeIgniter源码分析之Loader.php

CodeIgniter 2082℃

作者:Calix

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/**
* Loader Class
*
* Loader组件在CI里面也是一个很重要的组件,功能也比较明了。
* 如果已经阅读过Controller组件,会发现Controller组件的代码也只有十来行,但它却可以做很多事,一定程度上
* 要归功于Loader组件这个好助手或者好基友。
* 不过Loader组件的代码真的不少,主要以常用的几个方法以主线来探讨:model(),view(),library(),helper();
*/
class CI_Loader {

// All these are set automatically. Don't mess with them.
/**
* Nesting level of the output buffering mechanism
*/
protected $_ci_ob_level;
/**
* List of paths to load views from
*/
protected $_ci_view_paths = array();
/**
* List of paths to load libraries from
*/
protected $_ci_library_paths = array();
/**
* List of paths to load models from
*/
protected $_ci_model_paths = array();
/**
* List of paths to load helpers from
*/
protected $_ci_helper_paths = array();
/**
* List of loaded base classes
*/
protected $_base_classes = array(); // Set by the controller class
/**
* List of cached variables
*/
protected $_ci_cached_vars = array();
/**
* List of loaded classes
*/
protected $_ci_classes = array();
/**
* List of loaded files
*/
protected $_ci_loaded_files = array();
/**
* List of loaded models
*/
protected $_ci_models = array();
/**
* List of loaded helpers
*/
protected $_ci_helpers = array();
/**
* List of class name mappings
*/
protected $_ci_varmap = array('unit_test' => 'unit',
'user_agent' => 'agent');

/**
* Constructor
*/
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);

log_message('debug', "Loader Class Initialized");
}

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

/**
* Initialize the Loader
*/
public function initialize()
{
$this->_ci_classes = array();
$this->_ci_loaded_files = array();
$this->_ci_models = array();

//这个is_loaded方法就是在core/Common.php中定义的全局函数,在Loader组件还没有加载之前,由它来负责记录
//哪些核心类已经加载过,现在Loader组件要加载了,就把信息交给Loader组件,保存在Loader::$_base_classes中。
$this->_base_classes =& is_loaded();

//自动加载,加载项是你在config/autoload.php中设置的。
$this->_ci_autoloader();

return $this;
}

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

/**
* Is Loaded
*/
public function is_loaded($class)
{
if (isset($this->_ci_classes[$class]))
{
return $this->_ci_classes[$class];
}

return FALSE;
}

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

/**
* Class Loader
* $library为相应的类名,$params为实例化此类的时候可能要用到的参数,$object_name为给这个类的实例自义定一个名字。
*/
public function library($library = '', $params = NULL, $object_name = NULL)
{
//如果是通过数组加载多个,把它拆开再调用本方法,其实它可以递归调用多维数组,不过没有这个必要。
if (is_array($library))
{
foreach ($library as $class)
{
$this->library($class, $params);
}

return;
}

//接下来两个if都是关于合法性的判断。
if ($library == '' OR isset($this->_base_classes[$library]))
{
return FALSE;
}

if ( ! is_null($params) && ! is_array($params))
{
$params = NULL;
}

//真正把类加载进来的是下面这个方法。
$this->_ci_load_class($library, $params, $object_name);
}

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

/**
* Model Loader
*/
public function model($model, $name = '', $db_conn = FALSE)
{
//可以以数组形式同时加载多个$model
if (is_array($model))
{
foreach ($model as $babe)
{
$this->model($babe);
}
return;
}

if ($model == '')
{
return;
}

$path = '';

//判断是否包含目录信息
if (($last_slash = strrpos($model, '/')) !== FALSE)
{
$path = substr($model, 0, $last_slash + 1);

$model = substr($model, $last_slash + 1);
}

//如果没有给当前model定义名字,则以$model本身作为名字。
if ($name == '')
{
$name = $model;
}

//如果已经加载过此model,直接退出本函数。
if (in_array($name, $this->_ci_models, TRUE))
{
return;
}

$CI =& get_instance();
//如果加载的model名字与之前加载过的类有冲突,则报错。
if (isset($CI->$name))
{
show_error('The model name you are loading is the name of a resource that is already being used: '.$name);
}

//model文件必段是全小写。
$model = strtolower($model);

foreach ($this->_ci_model_paths as $mod_path)
{
if ( ! file_exists($mod_path.'models/'.$path.$model.'.php'))
{
continue;
}

//如果要求同时连接数据库。则调用Loader::database()方法加载数据库类。
if ($db_conn !== FALSE AND ! class_exists('CI_DB'))
{
if ($db_conn === TRUE)
{
$db_conn = '';
}

$CI->load->database($db_conn, FALSE, TRUE);
}

//加载父类model。
if ( ! class_exists('CI_Model'))
{
load_class('Model', 'core');
}

//引入当前model
require_once($mod_path.'models/'.$path.$model.'.php');

//把文件名的第一个字母大写作为类名,规定的命名规范。
$model = ucfirst($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;
}

show_error('Unable to locate the model you have specified: '.$model);
}

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

/**
* Database Loader
*/
public function database($params = '', $return = FALSE, $active_record = NULL)
{
$CI =& get_instance();
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);
}
$CI->db = '';

$CI->db =& DB($params, $active_record);
}

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

/**
* Load the Utilities Class
*/
public 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.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 Forge Class
*/
public function dbforge()
{
if ( ! class_exists('CI_DB'))
{
$this->database();
}

$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';

$CI->dbforge = new $class();
}

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

/**
* Load View
*
* Loader::view();方法可以和Loader::file()方法一并来阅读,实质上它们都是调用了Loader::_ci_load();方法。
*/
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));
}

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

/**
* Load File
*/
public function file($path, $return = FALSE)
{
return $this->_ci_load(array('_ci_path' => $path, '_ci_return' => $return));
}

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

/**
* Set Variables
*/
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;
}
}
}

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

/**
* Get Variable
*/
public function get_var($key)
{
return isset($this->_ci_cached_vars[$key]) ? $this->_ci_cached_vars[$key] : NULL;
}

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

/**
* Load Helper
*/
public function helper($helpers = array())
{
//Loader::_ci_prep_filename()方法只是处理文件名,以返回正确的数组而已。
//默认helper的文件名是以_helper为后缀,所以参数可以不用写_helper后缀,当然写也不会出错,因为
//Loader::_ci_prep_filename()会帮你处理掉。
foreach ($this->_ci_prep_filename($helpers, '_helper') as $helper)
{
//如果已经加载过此helper,则跳过。
if (isset($this->_ci_helpers[$helper]))
{
continue;
}

//helper的扩展。并非只有类可以扩展,函数也提供了扩展。注意这里是在APPPATH下。
$ext_helper = APPPATH.'helpers/'.config_item('subclass_prefix').$helper.'.php';
//如果存在对些helper的扩展。
if (file_exists($ext_helper))
{
//先引入CI自带的helper,再引入我们写的扩展。
$base_helper = BASEPATH.'helpers/'.$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;//继续下一个helper的引入。
}

//如果没有扩展的话,则分别从APPPATH和BASEPATH,即应用目录和系统目录下找到相应的helper。
//Loader::_ci_helper_paths默认是APPPATH和BASEPATH两个目录。如果你要再添加新的目录路径,可以
//通过Loader::add_package_path()方法设置(model,library等同理)
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;
}
}

if ( ! isset($this->_ci_helpers[$helper]))
{
show_error('Unable to load the requested file: helpers/'.$helper.'.php');
}
}
}

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

/**
* Load Helpers
*/
public function helpers($helpers = array())
{
$this->helper($helpers);
}

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

/**
* Loads a language file
*/
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);
}
}

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

/**
* Loads a config file
*/
//这里的config方法,实质是完完全全调用Config组件的load方法而已。
public function config($file = '', $use_sections = FALSE, $fail_gracefully = FALSE)
{
$CI =& get_instance();
$CI->config->load($file, $use_sections, $fail_gracefully);
}

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

/**
* Driver
*/
public function driver($library = '', $params = NULL, $object_name = NULL)
{
if ( ! class_exists('CI_Driver_Library'))
{
require BASEPATH.'libraries/Driver.php';
}

if ($library == '')
{
return FALSE;
}

if ( ! strpos($library, '/'))
{
$library = ucfirst($library).'/'.$library;
}

return $this->library($library, $params, $object_name);
}

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

/**
* Add Package Path
*/
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 =& $this->_ci_get_component('config');
array_unshift($config->_config_paths, $path);
}

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

/**
* Get Package Paths
*
*/
public function get_package_paths($include_base = FALSE)
{
return $include_base === TRUE ? $this->_ci_library_paths : $this->_ci_model_paths;
}

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

/**
* Remove Package Path
*/
public function remove_package_path($path = '', $remove_config_path = TRUE)
{
$config =& $this->_ci_get_component('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]);
}
}

$this->_ci_library_paths = array_unique(array_merge($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
*/
protected function _ci_load($_ci_data)
{
//这里相当于把数组里面的元素拆开成变量。
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;

//当Loader::_ci_load()方法是通过Loader::file()调用的时候,则会有$_ci_path的值,如果是
//如果Loader::view()调用的话,则有$_ci_view的值。
//如果$_ci_path不为空,则说明当前要加载普通文件。
if ($_ci_path != '')
{
//普通文件。这里只是获得文件名,以便找不到报错时候只报文件名而已。
$_ci_x = explode('/', $_ci_path);
$_ci_file = end($_ci_x);
}
else
{
//视图文件。
//下面两行操作也是为了让外部可以通过xxx.php或者直接xxx的方式进行传参而已。
$_ci_ext = pathinfo($_ci_view, PATHINFO_EXTENSION);
$_ci_file = ($_ci_ext == '') ? $_ci_view.'.php' : $_ci_view;

foreach ($this->_ci_view_paths as $view_file => $cascade)
{
//从Loader::$_ci_view_paths中遍历视图文件,如果找到则退出。
//(默认仅有APPPATH/view/下,当然也可以通过Loader::add_package()方法设置)
if (file_exists($view_file.$_ci_file))
{
$_ci_path = $view_file.$_ci_file;
$file_exists = TRUE;
break;
}

//如果没有找到,会根据这个$cascade判断允不允许继续往下一个路径寻找视图文件。
if ( ! $cascade)
{
break;
}
}
}

//如果找不到文件(普通或视图都一样),则报错。
if ( ! $file_exists && ! file_exists($_ci_path))
{
show_error('Unable to load the requested file: '.$_ci_file);
}

//下面这个也很关键,其实视图文件里面的代码都是在属于Loader组件的,什么意思?
//你可以随便写一个视图文件,然后在里面写上var_dump($this);可以发现,这个$this,是指Loader。
//为什么会这样子呢?再往下面十几行代码的地方就说明了这一点。
//这里是把CI所有的属性都开放给Loader组件用,这样在视图文件里面就可以通过$this->xxx的方式调用控制器
//所有的东西。

$_ci_CI =& get_instance();
foreach (get_object_vars($_ci_CI) as $_ci_key => $_ci_var)
{
if ( ! isset($this->$_ci_key))
{
$this->$_ci_key =& $_ci_CI->$_ci_key;
}
}

//在这里把在控制器里面通过$this->load->view("xxx",$data);中的$data解开,这就是为什么可以在视图文件
//中可以用$data里面的变量的原因。其实还可以通过Loader::vars()方法,设置这些变量,它们会首先保存在
//Loader::$_ci_cached_vars中
if (is_array($_ci_vars))
{
$this->_ci_cached_vars = array_merge($this->_ci_cached_vars, $_ci_vars);
}
extract($this->_ci_cached_vars);

//我们在控制器中调用$this->load->view()方法,实质视图并没有马上输出来,而是先将它放到缓冲区。
ob_start();

//就是这个地方,下面if中有一句eval(xxxx)以及else中有include;而里面的xxxx正是我们要加载的视图文件,
//所以这就是为什么在视图文件里,var_dump($this),会告诉你当前这个$this是Loader组件,因为视图的代码都是相当于
//嵌入这个地方。
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);
}

//经过上面的代码,我们的视图文件的内容已经放到了缓冲区了。

log_message('debug', 'File loaded: '.$_ci_path);

//一般情况下,$_ci_return都为FLASE,即不要求通过$this->load->view()返回输出内容,而是直接放到缓冲区静候处理;
//当然你也可以先拿出数据,在控制器里面处理一下,再输出,例如在控制器中
//$output=$this->load->view("x",$data,TRUE);,当为TRUE的时候,下面的代码就起作用了。
if ($_ci_return === TRUE)
{
$buffer = ob_get_contents();
@ob_end_clean();
return $buffer;
}

//下面这个很关键,因为有可能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
//从而导致多了一层缓冲。
//为了保证缓冲内容最后交给Output处理时,缓冲级别只比Loader组件加载时多1(这个1就是最父层的视图文件引起的)
//这里必须先flush掉当前层视图引起的这次缓冲,以保证Output正常工作。
if (ob_get_level() > $this->_ci_ob_level + 1)
{
ob_end_flush();
}
else
{
//如果不是多1,则说明当前引入的视图文件就是直接在控制器里面引入的那个,而不是由某个视图文件再引入的。

//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();
}
}

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

/**
* Load class
*/
protected function _ci_load_class($class, $params = NULL, $object_name = NULL)
{
//去掉后缀.php,是为了方便外部可以通过xxx.php也可以通过xxx.php来传入类名。同时去掉两端的/。
$class = str_replace('.php', '', trim($class, '/'));

//因为CI允许通过"dir1/dir2/classname"的格式来组织和加载类,所以还要判断类名中是否包括这些目录信息。
$subdir = '';
if (($last_slash = strrpos($class, '/')) !== FALSE)
{
//目录部分
$subdir = substr($class, 0, $last_slash + 1);

//类名部分
$class = substr($class, $last_slash + 1);
}

//CI允许类文件以大写字母开头或者全小写,下面的遍历,就是在遍历这两种情况。
foreach (array(ucfirst($class), strtolower($class)) as $class)
{
$subclass = APPPATH.'libraries/'.$subdir.config_item('subclass_prefix').$class.'.php';

//是否有我们开发人员自己写的扩展当前类的扩展?如果有的话,把它加载进来。
if (file_exists($subclass))
{
//先加载父类。
$baseclass = BASEPATH.'libraries/'.ucfirst($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);
}

if (in_array($subclass, $this->_ci_loaded_files))
{

if ( ! is_null($object_name))
{
$CI =& get_instance();
//我们加载的类最终都是加载给超级控制器的,如果超级控制器已经有的话,那么我们没必要加载。
//如果没有,则实例它并加载给控制器。,
if ( ! isset($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;
}

//加载类。
include_once($baseclass);
include_once($subclass);
//把已加载的类记录到Loader::_ci_loaded_files中。
$this->_ci_loaded_files[] = $subclass;

//调用Loader::_ci_init_class()方法进而实例化。
return $this->_ci_init_class($class, config_item('subclass_prefix'), $params, $object_name);
}

//如果是没有写扩展。方法和上面大致相同,最后都是通过调用Loader::_ci_init_class()方法进而实例化。

$is_duplicate = FALSE;
foreach ($this->_ci_library_paths as $path)
{
$filepath = $path.'libraries/'.$subdir.$class.'.php';
if ( ! file_exists($filepath))
{
continue;
}

if (in_array($filepath, $this->_ci_loaded_files))
{
if ( ! is_null($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

//其实正常的话,上面如果找到此类就找到,没找到就没有了。不过CI在会这里做最后的尝试。会不会是放到了一个同名的
//子目录下。
if ($subdir == '')
{
$path = strtolower($class).'/'.$class;
return $this->_ci_load_class($path, $params);
}

//没有找到就报错咯。
if ($is_duplicate == FALSE)
{
log_message('error', "Unable to load the requested class: ".$class);
show_error("Unable to load the requested class: ".$class);
}
}

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

//此方法是用于实例化已经把类文件include进来的类。
protected function _ci_init_class($class, $prefix = '', $config = FALSE, $object_name = NULL)
{
// Is there an associated config file for this class? Note: these should always be lowercase
if ($config === NULL)
{
// Fetch the config paths containing any package paths
$config_component = $this->_ci_get_component('config');

if (is_array($config_component->_config_paths))
{
// Break on the first found file, thus package files
// are not overridden by default paths
foreach ($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($class).'.php'))
{
include($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 ($prefix == '')
{
if (class_exists('CI_'.$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;
}

// 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;

// 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, and helpers to be loaded automatically.
*
*/
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;
}

// Autoload packages
if (isset($autoload['packages']))
{
foreach ($autoload['packages'] as $package_path)
{
$this->add_package_path($package_path);
}
}

// Load any custom config file
if (count($autoload['config']) > 0)
{
$CI =& get_instance();
foreach ($autoload['config'] as $key => $val)
{
$CI->config->load($val);
}
}

// Autoload helpers and languages
foreach (array('helper', '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']) AND isset($autoload['core']))
{
$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 all other libraries
foreach ($autoload['libraries'] as $item)
{
$this->library($item);
}
}

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

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

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

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

/**
* Get a reference to a specific library or model
*
*/
protected function &_ci_get_component($component)
{
$CI =& get_instance();
return $CI->$component;
}

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

/**
* Prep filename
*
* This function preps the name of various items to make loading them more reliable.
*
*/
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;
}
}
}

转载请注明:Calix » CodeIgniter源码分析之Loader.php

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