yii2源码学习笔记(六）

Behvaior类，Behavior类是所有事件类的基类：

目录yii2\base\Behavior.php

 <?php
 /**
  * @link http://www.yiiframework.com/
  * @copyright Copyright (c) 2008 Yii Software LLC
  * @license http://www.yiiframework.com/license/
  */

 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.
  * 用来增强现有组件的功能而不修改它的代码。它可以添加自己的方法和属性组件
  * 使他们可以直接通过组件访问。还可以响应组件触发的事件，拦截正常的代码执行。
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  * 继承父类Object
  */
 class Behavior extends Object
 {
     /**
      * @var Component the owner of this behavior 要附加行为对象的组件。
      */
     public $owner;

     /**
      * Declares event handlers for the [[owner]]'s events.
      * 声明[[owner]]的事件处理程序
      * Child classes may override this method to declare what PHP callbacks should
      * be attached to the events of the [[owner]] component.
      * 子类可以重写此方法 php回调应连接 [[owner]]组件。
      * 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.
      * 当行为被连接到owner时回调将附在[[owner]]的事件中，当行为从组件中分离时，它们将被分离
      * The callbacks can be any of the followings:
      *
      * - method in this behavior: `'handleClick'`, equivalent to `[$this, 'handleClick']`
      * - object method: `[$object, 'handleClick']`
      * - static method: `['Page', 'handleClick']`
      * - anonymous function: `function ($event) { ... }`
      *
      * The following is an example:
      *
      * ~~~
      * [
      *     Model::EVENT_BEFORE_VALIDATE => 'myBeforeValidate',
      *     Model::EVENT_AFTER_VALIDATE => 'myAfterValidate',
      * ]
      * ~~~
      *
      * @return array events (array keys) and the corresponding event handler methods (array values).
      * 事件和相应的事件处理方法
      */
     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]].
      * 默认设置[[owner]]属性并将事件处理程序绑定到组件
      * Make sure you call the parent implementation if you override this method. 如果重写方法，确保调用父类去实现
      * @param Component $owner the component that this behavior is to be attached to. 行为绑定到$owner组件
      */
     public function attach($owner)
     {
        $this->owner = $owner;//设置 $owner ，使得所依附的对象可以访问、操作
         foreach ($this->events() as $event => $handler) {
             //将准备响应的事件，通过所依附类的 on()方法 绑定到类上
             $owner->on($event, is_string($handler) ? [$this, $handler] : $handler);
         }
     }

     /**
      * Detaches the behavior object from the component. 解除绑定的行为
      * The default implementation will unset the [[owner]] property 默认取消 owner的属性
      * and detach event handlers declared in [[events]].    将events中的事件程序解除绑定
      * Make sure you call the parent implementation if you override this method.如果重写方法，确保调用父类去实现
      */
     public function detach()
     {
         if ($this->owner) {
             foreach ($this->events() as $event => $handler) {//遍历行为中 events() 返回的数组
                 //通过Component的 off() 将绑定到类上的事件解除
                 $this->owner->off($event, is_string($handler) ? [$this, $handler] : $handler);
             }
             $this->owner = null;//将 $owner 设置为 null ，表示这个解除绑定
         }
     }
 }

接下来看一下model类，它是所有模型的基类

目录yii2\base\Model.php

 <?php
 /**
  * @link http://www.yiiframework.com/
  * @copyright Copyright (c) 2008 Yii Software LLC
  * @license http://www.yiiframework.com/license/
  */

 namespace yii\base;

 use Yii;
 use ArrayAccess;
 use ArrayObject;
 use ArrayIterator;
 use ReflectionClass;
 use IteratorAggregate;
 use yii\helpers\Inflector;
 use yii\validators\RequiredValidator;
 use yii\validators\Validator;

 /**
  * Model is the base class for data models.
  *
  * IteratorAggregate（聚合式迭代器）接口 — 创建外部迭代器的接口, 需实现 getIterator 方法。
  * IteratorAggregate::getIterator — 获取一个外部迭代器， foreach 会调用该方法。
  *
  * ArrayAccess（数组式访问）接口 — 提供像访问数组一样访问对象的能力的接口， 需实现如下方法：
  * ArrayAccess::offsetExists — 检查一个偏移位置是否存在
  * ArrayAccess::offsetGet — 获取一个偏移位置的值
  * ArrayAccess::offsetSet — 设置一个偏移位置的值
  * ArrayAccess::offsetUnset — 复位一个偏移位置的值
  * 在 Model 中用于实现将 $model[$field] 替换为 $model->$field
  *
  * Model implements the following commonly used features:
  *
  * - attribute declaration: by default, every public class member is considered as
  *   a model attribute
  * - attribute labels: each attribute may be associated with a label for display purpose
  * - massive attribute assignment
  * - scenario-based validation
  *
  * Model also raises the following events when performing data validation:
  *
  * - [[EVENT_BEFORE_VALIDATE]]: an event raised at the beginning of [[validate()]]
  * - [[EVENT_AFTER_VALIDATE]]: an event raised at the end of [[validate()]]
  *
  * You may directly use Model to store model data, or extend it with customization.
  *
  * @property \yii\validators\Validator[] $activeValidators The validators applicable to the current
  * [[scenario]]. This property is read-only.
  * @property array $attributes Attribute values (name => value).
  * @property array $errors An array of errors for all attributes. Empty array is returned if no error. The
  * result is a two-dimensional array. See [[getErrors()]] for detailed description. This property is read-only.
  * @property array $firstErrors The first errors. The array keys are the attribute names, and the array values
  * are the corresponding error messages. An empty array will be returned if there is no error. This property is
  * read-only.
  * @property ArrayIterator $iterator An iterator for traversing the items in the list. This property is
  * read-only.
  * @property string $scenario The scenario that this model is in. Defaults to [[SCENARIO_DEFAULT]].
  * @property ArrayObject|\yii\validators\Validator[] $validators All the validators declared in the model.
  * This property is read-only.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
 class Model extends Component implements IteratorAggregate, ArrayAccess, Arrayable
 {
     use ArrayableTrait;

     /**
      * The name of the default scenario.
      * 默认场景的名称
      */
     const SCENARIO_DEFAULT = 'default';
     /**
      * @event ModelEvent an event raised at the beginning of [[validate()]]. You may set
      * [[ModelEvent::isValid]] to be false to stop the validation.
      */
     const EVENT_BEFORE_VALIDATE = 'beforeValidate';
     /**
      * @event Event an event raised at the end of [[validate()]]
      */
     const EVENT_AFTER_VALIDATE = 'afterValidate';

     /**
      * @var array validation errors (attribute name => array of errors)
      * 验证的错误信息
      */
     private $_errors;
     /**
      * @var ArrayObject list of validators
      */
     private $_validators;
     /**
      * @var string current scenario
      * 当前的场景，默认是default
      */
     private $_scenario = self::SCENARIO_DEFAULT;

     /**
      * Returns the validation rules for attributes.
      *
      * 返回属性的验证规则
      *
      * Validation rules are used by [[validate()]] to check if attribute values are valid.
      * Child classes may override this method to declare different validation rules.
      *
      * Each rule is an array with the following structure:
      *
      * ~~~
      * [
      *     ['attribute1', 'attribute2'],
      *     'validator type',
      *     'on' => ['scenario1', 'scenario2'],
      *     ...other parameters...
      * ]
      * ~~~
      *
      * where
      *
      *  - attribute list: required, specifies the attributes array to be validated, for single attribute you can pass string;
      *  - validator type: required, specifies the validator to be used. It can be a built-in validator name,
      *    a method name of the model class, an anonymous function, or a validator class name.
      *  - on: optional, specifies the [[scenario|scenarios]] array when the validation
      *    rule can be applied. If this option is not set, the rule will apply to all scenarios.
      *  - additional name-value pairs can be specified to initialize the corresponding validator properties.
      *    Please refer to individual validator class API for possible properties.
      *
      * A validator can be either an object of a class extending [[Validator]], or a model class method
      * (called *inline validator*) that has the following signature:
      *
      * ~~~
      * // $params refers to validation parameters given in the rule
      * function validatorName($attribute, $params)
      * ~~~
      *
      * In the above `$attribute` refers to currently validated attribute name while `$params` contains an array of
      * validator configuration options such as `max` in case of `string` validator. Currently validate attribute value
      * can be accessed as `$this->[$attribute]`.
      *
      * Yii also provides a set of [[Validator::builtInValidators|built-in validators]].
      * They each has an alias name which can be used when specifying a validation rule.
      *
      * Below are some examples:
      *
      * ~~~
      * [
      *     // built-in "required" validator
      *     [['username', 'password'], 'required'],
      *     // built-in "string" validator customized with "min" and "max" properties
      *     ['username', 'string', 'min' => 3, 'max' => 12],
      *     // built-in "compare" validator that is used in "register" scenario only
      *     ['password', 'compare', 'compareAttribute' => 'password2', 'on' => 'register'],
      *     // an inline validator defined via the "authenticate()" method in the model class
      *     ['password', 'authenticate', 'on' => 'login'],
      *     // a validator of class "DateRangeValidator"
      *     ['dateRange', 'DateRangeValidator'],
      * ];
      * ~~~
      *
      * Note, in order to inherit rules defined in the parent class, a child class needs to
      * merge the parent rules with child rules using functions such as `array_merge()`.
      *
      * @return array validation rules
      * @see scenarios()
      */
     public function rules()
     {
         return [];
     }

     /**
      * Returns a list of scenarios and the corresponding active attributes.
      * An active attribute is one that is subject to validation in the current scenario.
      * 返回场景及与之对应的 active 属性的列表
      * The returned array should be in the following format:
      *
      * ~~~
      * [
      *     'scenario1' => ['attribute11', 'attribute12', ...],
      *     'scenario2' => ['attribute21', 'attribute22', ...],
      *     ...
      * ]
      * ~~~
      *
      * By default, an active attribute is considered safe and can be massively assigned.
      * If an attribute should NOT be massively assigned (thus considered unsafe),
      * please prefix the attribute with an exclamation character (e.g. '!rank').
      *
      * The default implementation of this method will return all scenarios found in the [[rules()]]
      * declaration. A special scenario named [[SCENARIO_DEFAULT]] will contain all attributes
      * found in the [[rules()]]. Each scenario will be associated with the attributes that
      * are being validated by the validation rules that apply to the scenario.
      *
      * @return array a list of scenarios and the corresponding active attributes.
      */
     public function scenarios()
     {
         // 默认有 default 的场景
         $scenarios = [self::SCENARIO_DEFAULT => []];
         foreach ($this->getValidators() as $validator) {
             // 循环 validator，取出所有提到的场景，包括 on 和 except
             foreach ($validator->on as $scenario) {
                 $scenarios[$scenario] = [];
             }
             foreach ($validator->except as $scenario) {
                 $scenarios[$scenario] = [];
             }
         }
         // 取出所有场景的名称
         $names = array_keys($scenarios);

         foreach ($this->getValidators() as $validator) {
             if (empty($validator->on) && empty($validator->except)) {
                 // 如果 validator 即没有定义 on，也没有定义 except，就放到所有的场景中
                 foreach ($names as $name) {
                     // 循环 $validator 的所有属性
                     foreach ($validator->attributes as $attribute) {
                         $scenarios[$name][$attribute] = true;
                     }
                 }
             } elseif (empty($validator->on)) {
                 // 如果没有定义 on
                 foreach ($names as $name) {
                     if (!in_array($name, $validator->except, true)) {
                         // 而且场景不在 except 中， 就将这个属性加入到相应的场景中
                         foreach ($validator->attributes as $attribute) {
                             $scenarios[$name][$attribute] = true;
                         }
                     }
                 }
             } else {
                 // 如果定义了 on
                 foreach ($validator->on as $name) {
                     // 就将这个属性加入到 on 定义的场景中
                     foreach ($validator->attributes as $attribute) {
                         $scenarios[$name][$attribute] = true;
                     }
                 }
             }
         }

         /**
          * 将 $scenarios 从
          *
          * ~~~
          * [
          *     'default' => [],
          *     'scenario1' => ['attribute11' => true, 'attribute12' => true, ...],
          *     'scenario2' => ['attribute21' => true, 'attribute22' => true, ...],
          *     'scenario3' => [],
          *     ...
          * ]
          * ~~~
          * 转化为
          * ~~~
          * [
          *     'default' => [],
          *     'scenario1' => ['attribute11', 'attribute12', ...],
          *     'scenario2' => ['attribute21', 'attribute22', ...],
          *     ...
          * ]
          * ~~~
          */
         foreach ($scenarios as $scenario => $attributes) {
             // 去除掉没有属性值的场景
             if (empty($attributes) && $scenario !== self::SCENARIO_DEFAULT) {
                 unset($scenarios[$scenario]);
             } else {
                 // 取出场景中的属性名称
                 $scenarios[$scenario] = array_keys($attributes);
             }
         }

         return $scenarios;
     }

未完待续