学习yii2.0框架阅读代码(十)

vendor/yiisoft/yii2/base/Module.

<?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 yii\di\ServiceLocator;

/**
 * 模块和应用程序类的基类.
 *
 * 一个模块代表一个子应用程序包含MVC元素本身
 * models, views, controllers, etc.
 *
 * A module may consist of [[modules|sub-modules]].
 *
 * [[components|Components]] may be registered with the module so that they are globally
 * accessible within the module.
 *
 * @property array $aliases List of path aliases to be defined. The array keys are alias names (must start
 * with ‘@‘) and the array values are the corresponding paths or aliases. See [[setAliases()]] for an example.
 * This property is write-only.
 * @property string $basePath The root directory of the module.
 * @property string $controllerPath The directory that contains the controller classes. This property is
 * read-only.
 * @property string $layoutPath The root directory of layout files. Defaults to "[[viewPath]]/layouts".
 * @property array $modules The modules (indexed by their IDs).
 * @property string $uniqueId The unique ID of the module. This property is read-only.
 * @property string $viewPath The root directory of view files. Defaults to "[[basePath]]/views".
 *
 * @author Qiang Xue <[email protected]>
 * @since 2.0
 */
class Module extends ServiceLocator
{
    /**
     * @event 在执行ActionEvent方法时触发事件
     * 你可以设置[[ActionEvent:isValid]]是错误的取消操作执行。.
     */
    const EVENT_BEFORE_ACTION = ‘beforeAction‘;

    const EVENT_AFTER_ACTION = ‘afterAction‘;

    /**
     * @var array custom module parameters (name => value).
     */
    public $params = [];
    /**
     * @var 控制器ID
     */
    public $id;
    /**
     * @var 所属模块
     */
    public $module;
    /**
     * @var string|boolean the layout that should be applied for views within this module. This refers to a view name
     * relative to [[layoutPath]]. If this is not set, it means the layout value of the [[module|parent module]]
     * will be taken. If this is false, layout will be disabled within this module.
     */
    public $layout;
    /**
     *  @var 数组从控制器ID映射到控制器配置
     * 每一个名称-值对将指定一个控制器的配置.
     * 一个控制器配置可以是一个字符串或一个数组
     * 如果是前者,字符串应该是控制器的完全限定类名.
     * 如果是后者,数组元素必须包含一个“类”
     * the controller‘s fully qualified class name, and the rest of the name-value pairs
     * 例子,
     *
     * ~~~
     * [
     *   ‘account‘ => ‘app\controllers\UserController‘,
     *   ‘article‘ => [
     *      ‘class‘ => ‘app\controllers\PostController‘,
     *      ‘pageTitle‘ => ‘something new‘,
     *   ],
     * ]
     * ~~~
     */
    public $controllerMap = [];
    /**
     * @var string the namespace that controller classes are in.
     * This namespace will be used to load controller classes by prepending it to the controller
     * class name.
     *
     * If not set, it will use the `controllers` sub-namespace under the namespace of this module.
     * For example, if the namespace of this module is "foo\bar", then the default
     * controller namespace would be "foo\bar\controllers".
     *
     * See also the [guide section on autoloading](guide:concept-autoloading) to learn more about
     * defining namespaces and how classes are loaded.
     */
    public $controllerNamespace;
    /**
     * @var string the default route of this module. Defaults to ‘default‘.
     * The route may consist of child module ID, controller ID, and/or action ID.
     * For example, `help`, `post/create`, `admin/post/create`.
     * If action ID is not given, it will take the default value as specified in
     * [[Controller::defaultAction]].
     */
    public $defaultRoute = ‘default‘;

    /**
     * @var 字符串模块的根目录.
     */
    private $_basePath;
    /**
     * @var 字符串模块的根目录
     */
    private $_viewPath;
    /**
     * @var 字符串模块的根目录.
     */
    private $_layoutPath;
    /**
     * @var 这个模块所属的子模块
     */
    private $_modules = [];

    /**
     * 定义一个构造函数.
     * @param string $id the ID of this module
     * @param Module $parent the parent module (if any)
     * @param array $config name-value pairs that will be used to initialize the object properties
     */
    public function __construct($id, $parent = null, $config = [])
    {
        $this->id = $id;
        $this->module = $parent;
        parent::__construct($config);
    }

    /**
     * 返回当前请求的这个模块类的实例
     * If the module class is not currently requested, null will be returned.
     * This method is provided so that you access the module instance from anywhere within the module.
     * @return static|null the currently requested instance of this module class, or null if the module class is not requested.
     */
    public static function getInstance()
    {
        $class = get_called_class();
        return isset(Yii::$app->loadedModules[$class]) ? Yii::$app->loadedModules[$class] : null;
    }

    /**
     * Sets the currently requested instance of this module class.
     * @param Module|null $instance the currently requested instance of this module class.
     * If it is null, the instance of the calling class will be removed, if any.
     */
    public static function setInstance($instance)
    {
        // get_called_class和get_class获取的值都是带namespace的
        if ($instance === null) {
            // 如果实例不存在，就将其从$app的loadedModules移出掉
            unset(Yii::$app->loadedModules[get_called_class()]);
        } else {
            // 如果实例存在，就将其加入到$app的loadedModules里
            Yii::$app->loadedModules[get_class($instance)] = $instance;
        }
    }

    /**
     * 初始化模块.
     *
     * 调用此方法后,模块与属性值创建并初始化
     * 在配置。的默认实现将初始化[[controllerNamespace]]
     * if it is not set.
     *
     * If you override this method, please make sure you call the parent implementation.
     */

    public function init()
    {
        //取出控制器的命名空间，也可以理解为路径
        if ($this->controllerNamespace === null) {
            $class = get_class($this);
            if (($pos = strrpos($class, ‘\\‘)) !== false) {
                $this->controllerNamespace = substr($class, 0, $pos) . ‘\\controllers‘;
            }
        }
    }

php