namespace yii\base;

 /**
  * Behavior is the base class for all behavior classes.
  * 所有行为的基类
  * A behavior can be used to enhance the functionality of an existing component without modifying its code.
  * In particular, it can "inject" its own methods and properties into the component
  * and make them directly accessible via the component. It can also respond to the events triggered in the component
  * and thus intercept the normal code execution.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
 class Behavior extends Object
 {
     /**
      * @var 行为的依附对象
      */
     public $owner;

     /**
      * Declares event handlers for the [[owner]]'s events.
      * 表示这个行为将对类的何种事件进行何种反馈即可
      *
      * Child classes may override this method to declare what PHP callbacks should
      * be attached to the events of the [[owner]] component.
      *
      * The callbacks will be attached to the [[owner]]'s events when the behavior is
      * attached to the owner; and they will be detached from the events when
      * the behavior is detached from the component.
      *
      * The callbacks can be any of the following:
      * 事件handler可以是以下形式：
      *
      * - method in this behavior: `'handleClick'`, equivalent to `[$this, 'handleClick']`
      *  字符串，表示行为类的方法，和事件不同，事件总的字符串形式表示全局函数，这里表示当前行为类的方法
      * - object method: `[$object, 'handleClick']`
      *  一个对象或类的成员函数，以数组的形式
      * - static method: `['Page', 'handleClick']`
      * - anonymous function: `function ($event) { ... }`
      * 一个匿名函数
      *
      * The following is an example:
      *
      * ```php
      * [
      *     Model::EVENT_BEFORE_VALIDATE => 'myBeforeValidate',
      *     Model::EVENT_AFTER_VALIDATE => 'myAfterValidate',
      * ]
      * ```
      *
      * @return 行为所有要响应的事件.
      */
     public function events()
     {
         return [];
     }

     /**
      * Attaches the behavior object to the component.
      * 绑定行为到组件
      * The default implementation will set the [[owner]] property
      * and attach event handlers as declared in [[events]].
      * 该方法会默认设置[[owner]]属性，且添加事件处理程序绑定到组件
      * Make sure you call the parent implementation if you override this method.
      * @param Component $owner the component that this behavior is to be attached to.
      */
     public function attach($owner)
     {
         $this->owner = $owner;//设置行为的 $owner ，使得行为可以访问、操作所依附的对象
         foreach ($this->events() as $event => $handler) {//遍历行为中的 events() 返回的数组
             //将准备响应的事件，通过所依附类的 on() 绑定到类上
             $owner->on($event, is_string($handler) ? [$this, $handler] : $handler);//这里判断了事件是否是字符串的形式，如果是字符串，表示当前行为类的方法，用$this对象的形式添加
         }
     }

     /**
      * Detaches the behavior object from the component.
      * 解除行为的绑定
      * The default implementation will unset the [[owner]] property
      * 默认将 owner 属性设置为 null ，且解除绑定到类的处理程序
      * and detach event handlers declared in [[events]].
      *
      * Make sure you call the parent implementation if you override this method.
      */
     public function detach()
     {
         if ($this->owner) {
             foreach ($this->events() as $event => $handler) {//遍历行为中的 events() 返回的数组
                 //通过Component的 off() 将绑定到类上的事件hanlder解除下来
                 $this->owner->off($event, is_string($handler) ? [$this, $handler] : $handler);
             }
             $this->owner = null;//将 $owner 设置为 null ，表示这个行为没有依附到任何类上
         }
     }
 }

 namespace yii\base;

 use Yii;

 /**
  * Request represents a request that is handled by an [[Application]].
  *
  * @property boolean $isConsoleRequest The value indicating whether the current request is made via console.
  * @property string $scriptFile Entry script file path (processed w/ realpath()).
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
 abstract class Request extends Component
 {
     // 属性scriptFile，用于表示入口脚本
     private $_scriptFile;
     // 属性isConsoleRequest，用于表示是否是命令行应用
     private $_isConsoleRequest;

     /**
      * Resolves the current request into a route and the associated parameters.
      * 抽象函数，要求子类来实现 这个函数的功能主要是为了把Request解析成路由和相应的参数
      * @return array the first element is the route, and the second is the associated parameters.
      */
     abstract public function resolve();

     /**
      * Returns a value indicating whether the current request is made via command line
      * isConsoleRequest属性的getter函数   使用 PHP_SAPI 常量判断当前应用是否是命令行应用
      * @return boolean the value indicating whether the current request is made via console
      */
     public function getIsConsoleRequest()
     {
         // PHP_SAPI --判断解析php服务是由那种服务器软件，是采用那种协议
         return $this->_isConsoleRequest !== null ? $this->_isConsoleRequest : PHP_SAPI === 'cli';
     }

     /**
      * Sets the value indicating whether the current request is made via command line
      * isConsoleRequest属性的setter函数 用来设置是否是命令行应用
      * @param boolean $value the value indicating whether the current request is made via command line
      */
     public function setIsConsoleRequest($value)
     {
         $this->_isConsoleRequest = $value;
     }

     /**
      * Returns entry script file path.
      * scriptFile属性的getter函数     通过 $_SERVER['SCRIPT_FILENAME'] 来获取入口脚本名
      * @return string entry script file path (processed w/ realpath())
      * @throws InvalidConfigException if the entry script file path cannot be determined automatically.
      */
     public function getScriptFile()
     {
         if ($this->_scriptFile === null) {
             if (isset($_SERVER['SCRIPT_FILENAME'])) {
                 $this->setScriptFile($_SERVER['SCRIPT_FILENAME']);
             } else {
                 throw new InvalidConfigException('Unable to determine the entry script file path.');
             }
         }

         return $this->_scriptFile;
     }

     /**
      * Sets the entry script file path.
      * scriptFile属性的setter函数，用于设置入口脚本
      * The entry script file path can normally be determined based on the `SCRIPT_FILENAME` SERVER variable.
      * However, for some server configurations, this may not be correct or feasible.
      * This setter is provided so that the entry script file path can be manually specified.
      * @param string $value the entry script file path. This can be either a file path or a path alias.
      * @throws InvalidConfigException if the provided entry script file path is invalid.
      */
     public function setScriptFile($value)
     {
         $scriptFile = realpath(Yii::getAlias($value));
         if ($scriptFile !== false && is_file($scriptFile)) {
             $this->_scriptFile = $scriptFile;
         } else {
             throw new InvalidConfigException('Unable to determine the entry script file path.');
         }
     }
 }