$this->load->view()
$this->load->model()
$this->load->database()
$this->load->helper()
$this->load->config()
$this->load->add_package_path()
/** * Loader Class * * 用户加载views和files,常见的函数有model(),view(),library(),helper() * * Controller的好助手,$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(common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 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 * * @return string */ 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 $class(); } // -------------------------------------------------------------------- /** * 加载视图文件 */ public function view($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' => $return)); } // -------------------------------------------------------------------- /** * 设置变量 * * Once variables are set they become available within * the controller class and its "view" files. * */ public function vars($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 =& $this->_ci_get_component('config'); array_unshift($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 =& $this->_ci_get_component('config'); if ($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]); } } // 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 $this->load_vars() * function or via the second parameter of this function. We'll merge * the two types and cache them so that views that are embedded within * other views can have access to these variables. */ if (is_array($_ci_vars)) { $this->_ci_cached_vars = array_merge($this->_ci_cached_vars, $_ci_vars); } extract($this->_ci_cached_vars); /* * 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, $object_name); } } // END FOREACH // 如果还没有找到该class,最后的尝试是该class会不会在同名的子目录下 if ($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_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 == '') { //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) : $object; } // -------------------------------------------------------------------- /** * 获取CI某个组件的实例 */ protected function &_ci_get_component($component) { $CI =& get_instance(); return $CI->$component; } // -------------------------------------------------------------------- /** * 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; } } }