yii2源码学习笔记(十二）

继续了解controller基类。

    <span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Runs a request specified in terms of a route.在路径中指定的请求。
     * The route can be either an ID of an action within this controller or a complete route consisting
     * of module IDs, controller ID and action ID. If the route starts with a slash '/', the parsing of
     * the route will start from the application; otherwise, it will start from the parent module of this controller.
     * 该路径可以是控制器内的一个动作的标识，或由模块标识、控制器标识和动作标识组成的一个完整路径。
     * 如果该路径从一个“/”开始，该路径的解析将从应用程序开始；否则，它将从该控制器的父模块开始。
     * @param string $route the route to be handled, e.g., 'view', 'comment/view', '/admin/comment/view'.
     * @param array $params the parameters to be passed to the action.
     * @return mixed the result of the action.
     * @see runAction()
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span> function run($route, $<span style="color: #0000ff;">params</span> =<span style="color: #000000;"> [])
    {
        $pos </span>= strpos($route, <span style="color: #800000;">'</span><span style="color: #800000;">/</span><span style="color: #800000;">'</span><span style="color: #000000;">);
        </span><span style="color: #0000ff;">if</span> ($pos === <span style="color: #0000ff;">false</span>) {<span style="color: #008000;">//</span><span style="color: #008000;">判断是否以“/”开始 是则解析从应用程序开始；否则，它将从该控制器的父模块开始。</span>
            <span style="color: #0000ff;">return</span> $<span style="color: #0000ff;">this</span>->runAction($route, $<span style="color: #0000ff;">params</span><span style="color: #000000;">);
        } elseif ($pos </span>> <span style="color: #800080;">0</span><span style="color: #000000;">) {
            </span><span style="color: #0000ff;">return</span> $<span style="color: #0000ff;">this</span>->module->runAction($route, $<span style="color: #0000ff;">params</span><span style="color: #000000;">);
        } </span><span style="color: #0000ff;">else</span><span style="color: #000000;"> {
            </span><span style="color: #0000ff;">return</span> Yii::$app->runAction(ltrim($route, <span style="color: #800000;">'</span><span style="color: #800000;">/</span><span style="color: #800000;">'</span>), $<span style="color: #0000ff;">params</span><span style="color: #000000;">);
        }
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Binds the parameters to the action.将参数绑定到动作标识。
     * This method is invoked by [[Action]] when it begins to run with the given parameters.
     * 运行给定的参数时，该方法被调用。
     * @param Action $action the action to be bound with parameters.参数约束的操作。
     * @param array $params the parameters to be bound to the action.要约束的参数。
     * @return array the valid parameters that the action can run with.可以运行的有效参数。
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span> function bindActionParams($action, $<span style="color: #0000ff;">params</span><span style="color: #000000;">)
    {
        </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> [];
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Creates an action based on the given action ID. 根据给定的操作标识创建一个action。
     * The method first checks if the action ID has been declared in [[actions()]]. If so,
     * it will use the configuration declared there to create the action object.
     * If not, it will look for a controller method whose name is in the format of `actionXyz`
     * where `Xyz` stands for the action ID. If found, an [[InlineAction]] representing that
     * method will be created and returned.
     * 该方法首先检查动作标识是否在 [[actions()]]设置，如果是将使用配置声明来创建操作对象。
     * 如果不是，它会寻找控制器方法`Xyz` 的 `actionXyz`作为动作标识，调用[[InlineAction]]方法创建对象
     * @param string $id the action ID. 
     * @return Action the newly created action instance. Null if the ID doesn't resolve into any action.
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span><span style="color: #000000;"> function createAction($id)
    {
        </span><span style="color: #0000ff;">if</span> ($id === <span style="color: #800000;">''</span><span style="color: #000000;">) {
             </span><span style="color: #008000;">//</span><span style="color: #008000;"> 如果action的id为空，就是用默认的action</span>
            $id = $<span style="color: #0000ff;">this</span>-><span style="color: #000000;">defaultAction;
        }

        $actionMap </span>= $<span style="color: #0000ff;">this</span>->actions();<span style="color: #008000;">//</span><span style="color: #008000;"> 获取actions方法中的定义的actionMap</span>
        <span style="color: #0000ff;">if</span><span style="color: #000000;"> (isset($actionMap[$id])) {
             </span><span style="color: #008000;">//</span><span style="color: #008000;"> 如果操作标识在actionMap中，就去创建这个action</span>
            <span style="color: #0000ff;">return</span> Yii::createObject($actionMap[$id], [$id, $<span style="color: #0000ff;">this</span><span style="color: #000000;">]);
        } elseif (preg_match(</span><span style="color: #800000;">'</span><span style="color: #800000;">/^[a-z0-9\\-_]+$/</span><span style="color: #800000;">'</span>, $id) && strpos($id, <span style="color: #800000;">'</span><span style="color: #800000;">--</span><span style="color: #800000;">'</span>) === <span style="color: #0000ff;">false</span> && trim($id, <span style="color: #800000;">'</span><span style="color: #800000;">-</span><span style="color: #800000;">'</span>) ===<span style="color: #000000;"> $id) {
             </span><span style="color: #008000;">//</span><span style="color: #008000;"> 如果id符合命名规范，而且两边不存在-
            </span><span style="color: #008000;">//</span><span style="color: #008000;"> 用于拼接controller类名类似的方法拼接action方法的名称</span>
            $methodName = <span style="color: #800000;">'</span><span style="color: #800000;">action</span><span style="color: #800000;">'</span> . str_replace(<span style="color: #800000;">'</span> <span style="color: #800000;">'</span>, <span style="color: #800000;">''</span>, ucwords(implode(<span style="color: #800000;">'</span> <span style="color: #800000;">'</span>, explode(<span style="color: #800000;">'</span><span style="color: #800000;">-</span><span style="color: #800000;">'</span><span style="color: #000000;">, $id))));
            </span><span style="color: #0000ff;">if</span> (method_exists($<span style="color: #0000ff;">this</span><span style="color: #000000;">, $methodName)) {
                </span><span style="color: #008000;">//</span><span style="color: #008000;"> 如果方法存在，就实例化</span>
                $method = <span style="color: #0000ff;">new</span> \ReflectionMethod($<span style="color: #0000ff;">this</span><span style="color: #000000;">, $methodName);
                </span><span style="color: #0000ff;">if</span> ($method->isPublic() && $method->getName() ===<span style="color: #000000;"> $methodName) {
                    </span><span style="color: #008000;">//</span><span style="color: #008000;"> 如果方法是public的，就new一个InlineAction返回</span>
                    <span style="color: #0000ff;">return</span> <span style="color: #0000ff;">new</span> InlineAction($id, $<span style="color: #0000ff;">this</span><span style="color: #000000;">, $methodName);
                }
            }
        }

        </span><span style="color: #0000ff;">return</span> <span style="color: #0000ff;">null</span><span style="color: #000000;">;
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * This method is invoked right before an action is executed.
     * 在执行操作之前调用此方法。
     * The method will trigger the [[EVENT_BEFORE_ACTION]] event. The return value of the method
     * will determine whether the action should continue to run.
     * 方法将触发 [[EVENT_BEFORE_ACTION]] 事件，返回值确定该操作是否执行
     * If you override this method, your code should look like the following:
     *
     * ```php
     * public function beforeAction($action)
     * {
     *     if (parent::beforeAction($action)) {
     *         // your custom code here
     *         return true;  // or false if needed
     *     } else {
     *         return false;
     *     }
     * }
     * ```
     *
     * @param Action $action the action to be executed. 执行的操作
     * @return boolean whether the action should continue to run.确定操作是否应该继续运行。
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span><span style="color: #000000;"> function beforeAction($action)
    {
        $</span><span style="color: #0000ff;">event</span> = <span style="color: #0000ff;">new</span><span style="color: #000000;"> ActionEvent($action);
        $</span><span style="color: #0000ff;">this</span>->trigger(self::EVENT_BEFORE_ACTION, $<span style="color: #0000ff;">event</span><span style="color: #000000;">);
        </span><span style="color: #0000ff;">return</span> $<span style="color: #0000ff;">event</span>-><span style="color: #000000;">isValid;
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * This method is invoked right after an action is executed.
     * 在执行操作之后调用此方法。
     * The method will trigger the [[EVENT_AFTER_ACTION]] event. The return value of the method
     * will be used as the action return value.
     *
     * If you override this method, your code should look like the following:
     *
     * ```php
     * public function afterAction($action, $result)
     * {
     *     $result = parent::afterAction($action, $result);
     *     // your custom code here
     *     return $result;
     * }
     * ```
     *
     * @param Action $action the action just executed. 刚刚执行的操作。
     * @param mixed $result the action return result. 操作返回值
     * @return mixed the processed action result. 处理结果。
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span><span style="color: #000000;"> function afterAction($action, $result)
    {
        $</span><span style="color: #0000ff;">event</span> = <span style="color: #0000ff;">new</span><span style="color: #000000;"> ActionEvent($action);
        $</span><span style="color: #0000ff;">event</span>->result =<span style="color: #000000;"> $result;
        $</span><span style="color: #0000ff;">this</span>->trigger(self::EVENT_AFTER_ACTION, $<span style="color: #0000ff;">event</span><span style="color: #000000;">);
        </span><span style="color: #0000ff;">return</span> $<span style="color: #0000ff;">event</span>-><span style="color: #000000;">result;
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Returns all ancestor modules of this controller. 获取当前控制器所有的父模块
     * The first module in the array is the outermost one (i.e., the application instance),
     * while the last is the innermost one.
     * 数组中的第一个模块是最外层的一个，最后一个模块是最内层的。
     * @return Module[] all ancestor modules that this controller is located within.当前控制器所有的父模块
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span><span style="color: #000000;"> function getModules()
    {
        </span><span style="color: #008000;">//</span><span style="color: #008000;"> 当前controller的module组成的数组</span>
        $modules = [$<span style="color: #0000ff;">this</span>-><span style="color: #000000;">module];
        $module </span>= $<span style="color: #0000ff;">this</span>-><span style="color: #000000;">module;
        </span><span style="color: #0000ff;">while</span> ($module->module !== <span style="color: #0000ff;">null</span><span style="color: #000000;">) {
             </span><span style="color: #008000;">//</span><span style="color: #008000;"> 将外面的module插入到modules数组的开头</span>
            array_unshift($modules, $module-><span style="color: #000000;">module);
            $module </span>= $module-><span style="color: #000000;">module;
        }
        </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> $modules;
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * @return string the controller ID that is prefixed with the module ID (if any).
     * 返回控制器id
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span><span style="color: #000000;"> function getUniqueId()
    {
        </span><span style="color: #008000;">//</span><span style="color: #008000;">如果当前所属模块为application，则就为当前id,否则要面要加上模块id</span>
        <span style="color: #0000ff;">return</span> $<span style="color: #0000ff;">this</span>->module instanceof Application ? $<span style="color: #0000ff;">this</span>->id : $<span style="color: #0000ff;">this</span>->module->getUniqueId() . <span style="color: #800000;">'</span><span style="color: #800000;">/</span><span style="color: #800000;">'</span> . $<span style="color: #0000ff;">this</span>-><span style="color: #000000;">id;
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Returns the route of the current request.    获取默认请求的路由信息
     * @return string the route (module ID, controller ID and action ID) of the current request. 
     * 当前请求的路由（模块标识、控制器标识和操作标识）
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span><span style="color: #000000;"> function getRoute()
    {
        </span><span style="color: #0000ff;">return</span> $<span style="color: #0000ff;">this</span>->action !== <span style="color: #0000ff;">null</span> ? $<span style="color: #0000ff;">this</span>->action->getUniqueId() : $<span style="color: #0000ff;">this</span>-><span style="color: #000000;">getUniqueId();
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Renders a view and applies layout if available.
     * 如果有布局渲染视图文件和布局文件
     * The view to be rendered can be specified in one of the following formats:
     *
     * - path alias (e.g. "@app/views/site/index");
     * - absolute path within application (e.g. "//site/index"): the view name starts with double slashes.
     *   The actual view file will be looked for under the [[Application::viewPath|view path]] of the application.
     * - absolute path within module (e.g. "/site/index"): the view name starts with a single slash.
     *   The actual view file will be looked for under the [[Module::viewPath|view path]] of [[module]].
     * - relative path (e.g. "index"): the actual view file will be looked for under [[viewPath]].
     *
     * To determine which layout should be applied, the following two steps are conducted:
     * 确定应用布局文件类型的步骤：
     * 1. In the first step, it determines the layout name and the context module:
     * 首先确定布局文件名和背景模块
     * - If [[layout]] is specified as a string, use it as the layout name and [[module]] as the context module;
     * - If [[layout]] is null, search through all ancestor modules of this controller and find the first
     *   module whose [[Module::layout|layout]] is not null. The layout and the corresponding module
     *   are used as the layout name and the context module, respectively. If such a module is not found
     *   or the corresponding layout is not a string, it will return false, meaning no applicable layout.
     *   如果布局文件是字符串，也就是设置布局文件，则直接调用。 如果没有设置布局文件，则查找所有的父模块的布局文件。
     * 2. In the second step, it determines the actual layout file according to the previously found layout name
     *    and context module. The layout name can be:
     *    应用下的布局文件，以“/”开头，这个会从应用程序的布局文件目录下面查找布局文件
     * - a path alias (e.g. "@app/views/layouts/main");
     * - an absolute path (e.g. "/main"): the layout name starts with a slash. The actual layout file will be
     *   looked for under the [[Application::layoutPath|layout path]] of the application;
     * - a relative path (e.g. "main"): the actual layout file will be looked for under the
     *   [[Module::layoutPath|layout path]] of the context module.
     *
     * If the layout name does not contain a file extension, it will use the default one `.php`.
     * 如果布局文件没有扩展名，则默认为.php
     * @param string $view the view name.
     * @param array $params the parameters (name-value pairs) that should be made available in the view.
     * These parameters will not be available in the layout.
     * @return string the rendering result.
     * @throws InvalidParamException if the view file or the layout file does not exist.
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span> function render($view, $<span style="color: #0000ff;">params</span> =<span style="color: #000000;"> [])
    {
        </span><span style="color: #008000;">//</span><span style="color: #008000;">由view对象渲染视图文件</span>
        $content = $<span style="color: #0000ff;">this</span>->getView()->render($view, $<span style="color: #0000ff;">params</span>, $<span style="color: #0000ff;">this</span><span style="color: #000000;">);
        </span><span style="color: #0000ff;">return</span> $<span style="color: #0000ff;">this</span>->renderContent($content);<span style="color: #008000;">//</span><span style="color: #008000;">渲染布局文件</span>
<span style="color: #000000;">    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Renders a static string by applying a layout.    配合render方法渲染布局文件
     * @param string $content the static string being rendered  被渲染的静态字符串
     * @return string the rendering result of the layout with the given static string as the `$content` variable.
     * If the layout is disabled, the string will be returned back.
     * 以给定的静态字符串作为“$content”变量布局的渲染结果。如果布局被禁用，将返回该字符串。
     * @since 2.0.1
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span><span style="color: #000000;"> function renderContent($content)
    {
        $layoutFile </span>= $<span style="color: #0000ff;">this</span>->findLayoutFile($<span style="color: #0000ff;">this</span>->getView()); <span style="color: #008000;">//</span><span style="color: #008000;">查找布局文件</span>
        <span style="color: #0000ff;">if</span> ($layoutFile !== <span style="color: #0000ff;">false</span>) {<span style="color: #008000;">//</span><span style="color: #008000;">由view对象渲染布局文件，并把上视图结果作为content变量传递到布局中，</span>
            <span style="color: #0000ff;">return</span> $<span style="color: #0000ff;">this</span>->getView()->renderFile($layoutFile, [<span style="color: #800000;">'</span><span style="color: #800000;">content</span><span style="color: #800000;">'</span> => $content], $<span style="color: #0000ff;">this</span><span style="color: #000000;">);
        } </span><span style="color: #0000ff;">else</span><span style="color: #000000;"> {
            </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> $content;
        }
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Renders a view without applying layout.渲染视图文件不应用布局
     * This method differs from [[render()]] in that it does not apply any layout.
     * 这种方法不同于[[render()]]，它不使用任何布局。
     * @param string $view the view name. Please refer to [[render()]] on how to specify a view name.
     * 视图名称。根据[[render()]]指定一个视图名称。
     * @param array $params the parameters (name-value pairs) that should be made available in the view.
     * 在视图中提供的参数(name-value pairs)
     * @return string the rendering result.渲染结果。
     * @throws InvalidParamException if the view file does not exist.如果视图文件不存在，抛出异常
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span> function renderPartial($view, $<span style="color: #0000ff;">params</span> =<span style="color: #000000;"> [])
    {
        </span><span style="color: #0000ff;">return</span> $<span style="color: #0000ff;">this</span>->getView()->render($view, $<span style="color: #0000ff;">params</span>, $<span style="color: #0000ff;">this</span><span style="color: #000000;">);
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Renders a view file. 渲染一个文件
     * @param string $file the view file to be rendered. This can be either a file path or a path alias.
     * 要呈现的视图文件。可以是一个文件路径或路径别名。
     * @param array $params the parameters (name-value pairs) that should be made available in the view.
     * 在视图中提供的参数(name-value pairs)
     * @return string the rendering result.渲染结果
     * @throws InvalidParamException if the view file does not exist.如果视图文件不存在，抛出异常
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span> function renderFile($file, $<span style="color: #0000ff;">params</span> =<span style="color: #000000;"> [])
    {
        </span><span style="color: #0000ff;">return</span> $<span style="color: #0000ff;">this</span>->getView()->renderFile($file, $<span style="color: #0000ff;">params</span>, $<span style="color: #0000ff;">this</span><span style="color: #000000;">);
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Returns the view object that can be used to render views or view files.
     * 返回渲染视图或视图文件的view对象。
     * The [[render()]], [[renderPartial()]] and [[renderFile()]] methods will use
     * this view object to implement the actual view rendering.
     * [[render()]], [[renderPartial()]] and [[renderFile()]] 方法将使用视图对象实现视图显示。
     * If not set, it will default to the "view" application component.如果未设置，则默认为“view”应用程序组件。
     * @return View|\yii\web\View the view object that can be used to render views or view files.
     * 渲染视图或视图文件的view对象。
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span><span style="color: #000000;"> function getView()
    {
        </span><span style="color: #0000ff;">if</span> ($<span style="color: #0000ff;">this</span>->_view === <span style="color: #0000ff;">null</span><span style="color: #000000;">) {
            $</span><span style="color: #0000ff;">this</span>->_view = Yii::$app-><span style="color: #000000;">getView();
        }
        </span><span style="color: #0000ff;">return</span> $<span style="color: #0000ff;">this</span>-><span style="color: #000000;">_view;
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Sets the view object to be used by this controller.
     * @param View|\yii\web\View $view the view object that can be used to render views or view files.
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span><span style="color: #000000;"> function setView($view)
    {
        $</span><span style="color: #0000ff;">this</span>->_view =<span style="color: #000000;"> $view;
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Returns the directory containing view files for this controller.返回该控制器包含视图文件的目录。
     * The default implementation returns the directory named as controller [[id]] under the [[module]]'s
     * [[viewPath]] directory.默认返回目录命名为控制器[[id]] 下的 [[module]]的[[viewPath]]目录。
     * @return string the directory containing the view files for this controller.
     * 包含此控制器的视图文件的目录。
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span><span style="color: #000000;"> function getViewPath()
    {
        </span><span style="color: #0000ff;">return</span> $<span style="color: #0000ff;">this</span>->module->getViewPath() . DIRECTORY_SEPARATOR . $<span style="color: #0000ff;">this</span>-><span style="color: #000000;">id;
    }

    </span><span style="color: #008000;">/*</span><span style="color: #008000;">*
     * Finds the applicable layout file.查找适用的布局文件。
     * @param View $view the view object to render the layout file.呈现布局文件视图对象。
     * @return string|boolean the layout file path, or false if layout is not needed.
     * Please refer to [[render()]] on how to specify this parameter.
     * 布局文件路径，或者不需要布局。参阅[[render()]]如何指定此参数。
     * @throws InvalidParamException if an invalid path alias is used to specify the layout.
     * 如果使用了无效的路径别名指定布局。抛出异常
     </span><span style="color: #008000;">*/</span>
    <span style="color: #0000ff;">public</span><span style="color: #000000;"> function findLayoutFile($view)
    {
        $module </span>= $<span style="color: #0000ff;">this</span>-><span style="color: #000000;">module;
        </span><span style="color: #0000ff;">if</span> (is_string($<span style="color: #0000ff;">this</span>-><span style="color: #000000;">layout)) {
             </span><span style="color: #008000;">//</span><span style="color: #008000;">如果当前控制器设置了布局文件，则直接使用所设置的布局文件</span>
            $layout = $<span style="color: #0000ff;">this</span>-><span style="color: #000000;">layout;
        } elseif ($</span><span style="color: #0000ff;">this</span>->layout === <span style="color: #0000ff;">null</span><span style="color: #000000;">) {
             </span><span style="color: #008000;">//</span><span style="color: #008000;">如果没有设置布局文件，查找所有的父模块的布局文件。</span>
            <span style="color: #0000ff;">while</span> ($module !== <span style="color: #0000ff;">null</span> && $module->layout === <span style="color: #0000ff;">null</span><span style="color: #000000;">) {
                $module </span>= $module-><span style="color: #000000;">module;
            }
            </span><span style="color: #0000ff;">if</span> ($module !== <span style="color: #0000ff;">null</span> && is_string($module-><span style="color: #000000;">layout)) {
                $layout </span>= $module-><span style="color: #000000;">layout;
            }
        }

        </span><span style="color: #0000ff;">if</span> (!<span style="color: #000000;">isset($layout)) {
            </span><span style="color: #0000ff;">return</span> <span style="color: #0000ff;">false</span>;<span style="color: #008000;">//</span><span style="color: #008000;">如果没有设置布局文件，返回false</span>
<span style="color: #000000;">        }

        </span><span style="color: #0000ff;">if</span> (strncmp($layout, <span style="color: #800000;">'</span><span style="color: #800000;">@</span><span style="color: #800000;">'</span>, <span style="color: #800080;">1</span>) === <span style="color: #800080;">0</span><span style="color: #000000;">) {
            $file </span>= Yii::getAlias($layout);<span style="color: #008000;">//</span><span style="color: #008000;">以“@”开头，会在别名路径中查找布局文件</span>
        } elseif (strncmp($layout, <span style="color: #800000;">'</span><span style="color: #800000;">/</span><span style="color: #800000;">'</span>, <span style="color: #800080;">1</span>) === <span style="color: #800080;">0</span>) {<span style="color: #008000;">//</span><span style="color: #008000;">以“/”开头，会从应用程序的布局文件目录下面查找布局文件</span>
            $file = Yii::$app->getLayoutPath() . DIRECTORY_SEPARATOR . substr($layout, <span style="color: #800080;">1</span><span style="color: #000000;">);
        } </span><span style="color: #0000ff;">else</span> {<span style="color: #008000;">//</span><span style="color: #008000;">从当前模块的布局文件目录下查找布局文件</span>
            $file = $module-><span style="color: #000000;">getLayoutPath() . DIRECTORY_SEPARATOR . $layout;
        }

        </span><span style="color: #0000ff;">if</span> (pathinfo($file, PATHINFO_EXTENSION) !== <span style="color: #800000;">''</span><span style="color: #000000;">) {
            </span><span style="color: #0000ff;">return</span> $file;<span style="color: #008000;">//</span><span style="color: #008000;">如果布局文件有文件扩展名，返回文件</span>
<span style="color: #000000;">        }
        $path </span>= $file . <span style="color: #800000;">'</span><span style="color: #800000;">.</span><span style="color: #800000;">'</span> . $view->defaultExtension;<span style="color: #008000;">//</span><span style="color: #008000;">拼接默认的文件扩展名。</span>
        <span style="color: #0000ff;">if</span> ($view->defaultExtension !== <span style="color: #800000;">'</span><span style="color: #800000;">php</span><span style="color: #800000;">'</span> && !<span style="color: #000000;">is_file($path)) {
            $path </span>= $file . <span style="color: #800000;">'</span><span style="color: #800000;">.php</span><span style="color: #800000;">'</span>;<span style="color: #008000;">//</span><span style="color: #008000;">如果文件不存在，并且，默认的文件扩展名也不是php，则加上.php作为扩展名。</span>
<span style="color: #000000;">        }

        </span><span style="color: #0000ff;">return</span><span style="color: #000000;"> $path;
    }</span>