yii2源码学习笔记(十七），yii2源码学习笔记_PHP教程
时间：2021-07-01 10:21:17
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yii2源码学习笔记(十七），yii2源码学习笔记
Theme 类，应用的主题，通过替换路径实现主题的应用，方法为获取根路径和根链接：yii2\base\Theme.php
1 php
2 /**
3 * @link http://www.yiiframework.com/
4 * @copyright Copyright (c) 2008 Yii Software LLC
5 * @license http://www.yiiframework.com/license/
6 */
7
8 namespace yii\base;
9
10 use Yii;
11 use yii\helpers\FileHelper;
12
13 /**
14 * Theme represents an application theme.
15 * Theme 类，应用的主题
16 * When [[View]] renders a view file, it will check the [[View::theme|active theme]]
17 * to see if there is a themed version of the view file exists. If so, the themed version will be rendered instead.
18 * 视图对象[[View]]渲染视图文件的时候，会检查视图的主题是否存在，如果存在则渲染主题取代默认样式
19 * A theme is a directory consisting of view files which are meant to replace their non-themed counterparts.
20 *
21 * Theme uses [[pathMap]] to achieve the view file replacement:
22 *
23 * 1. It first looks for a key in [[pathMap]] that is a substring of the given view file path;
24 * 首先查找关键字，关键字是一个给定的视图路径的字符串
25 * 2. If such a key exists, the corresponding value will be used to replace the corresponding part
26 * in the view file path;关键字存在，则用对应值替换给定的视图文件路径中对应的部分
27 * 3. It will then check if the updated view file exists or not. If so, that file will be used
28 * to replace the original view file.检查替换后的路径对应的文件是否存在，存在就替换原文件
29 * 4. If Step 2 or 3 fails, the original view file will be used.
30 * 2和3失败的话，返回原来的路径
31 * For example, if [[pathMap]] is `['@app/views' => '@app/themes/basic']`,
32 * then the themed version for a view file `@app/views/site/index.php` will be
33 * `@app/themes/basic/site/index.php`.
34 *
35 * It is possible to map a single path to multiple paths. For example,
36 *
37 * ~~~
38 * 'pathMap' => [
39 * '@app/views' => [
40 * '@app/themes/christmas',
41 * '@app/themes/basic',
42 * ],
43 * ]
44 * ~~~
45 *
46 * In this case, the themed version could be either `@app/themes/christmas/site/index.php` or
47 * `@app/themes/basic/site/index.php`. The former has precedence over the latter if both files exist.
48 *
49 * To use a theme, you should configure the [[View::theme|theme]] property of the "view" application
50 * component like the following:
51 *
52 * ~~~
53 * 'view' => [
54 * 'theme' => [
55 * 'basePath' => '@app/themes/basic',
56 * 'baseUrl' => '@web/themes/basic',
57 * ],
58 * ],
59 * ~~~
60 *
61 * The above configuration specifies a theme located under the "themes/basic" directory of the Web folder
62 * that contains the entry script of the application. If your theme is designed to handle modules,
63 * you may configure the [[pathMap]] property like described above.
64 *
65 * @property string $basePath The root path of this theme. All resources of this theme are located under this
66 * directory.
67 * @property string $baseUrl The base URL (without ending slash) for this theme. All resources of this theme
68 * are considered to be under this base URL. This property is read-only.
69 *
70 * @author Qiang Xue
71 * @since 2.0
72 */
73 class Theme extends Component
74 {
75 /**
76 * @var array the mapping between view directories and their corresponding themed versions.
77 * This property is used by [[applyTo()]] when a view is trying to apply the theme.
78 * Path aliases can be used when specifying directories.
79 * 路径映射属性 设置替换映射关系
80 * If this property is empty or not set, a mapping [[Application::basePath]] to [[basePath]] will be used.
81 */
82 public $pathMap;
83
84 private $_baseUrl;//设置要访问资源的url
85
86 /**
87 * @return string the base URL (without ending slash) for this theme. All resources of this theme are considered
88 * to be under this base URL. 返回当前主题的基础链接，其他资源都在链接里
89 */
90 public function getBaseUrl()
91 {
92 return $this->_baseUrl;
93 }
94
95 /**
96 * @param $url string the base URL or path alias for this theme. All resources of this theme are considered
97 * to be under this base URL. 设置基础链接
98 */
99 public function setBaseUrl($url)
100 {
101 $this->_baseUrl = rtrim(Yii::getAlias($url), '/');
102 }
103
104 private $_basePath;//根路径
105
106 /**
107 * @return string the root path of this theme. All resources of this theme are located under this directory.
108 * 得到当前主题的根路径
109 * @see pathMap
110 */
111 public function getBasePath()
112 {
113 return $this->_basePath;
114 }
115
116 /**
117 * @param string $path the root path or path alias of this theme. All resources of this theme are located
118 * under this directory. 设置当前主题根路径
119 * @see pathMap
120 */
121 public function setBasePath($path)
122 {
123 $this->_basePath = Yii::getAlias($path);
124 }
125
126 /**
127 * Converts a file to a themed file if possible. 将一个文件替换主题文件
128 * If there is no corresponding themed file, the original file will be returned.
129 * 没有相应的主题文件，返回原文件。
130 * @param string $path the file to be themed
131 * @return string the themed file, or the original file if the themed version is not available.
132 * @throws InvalidConfigException if [[basePath]] is not set
133 */
134 public function applyTo($path)
135 {
136 $pathMap = $this->pathMap; //取得路径映射
137 if (empty($pathMap)) {//没有设置值 抛出异常
138 if (($basePath = $this->getBasePath()) === null) {
139 throw new InvalidConfigException('The "basePath" property must be set.');
140 }
141 //设置值为[模块根路径=>主题根路径]的形式
142 $pathMap = [Yii::$app->getBasePath() => [$basePath]];
143 }
144
145 $path = FileHelper::normalizePath($path);//对路径中的"/"."\"进行统一
146
147 foreach ($pathMap as $from => $tos) {
148 //映射数组中的来源
149 $from = FileHelper::normalizePath(Yii::getAlias($from)) . DIRECTORY_SEPARATOR;
150 if (strpos($path, $from) === 0) {//如果在$path中有可替换的旧值
151 $n = strlen($from);
152 foreach ((array) $tos as $to) {
153 $to = FileHelper::normalizePath(Yii::getAlias($to)) . DIRECTORY_SEPARATOR;
154 $file = $to . substr($path, $n);//把$path中的$from替换为$to
155 if (is_file($file)) {
156 return $file; //是文件直接返回
157 }
158 }
159 }
160 }
161
162 return $path;
163 }
164
165 /**
166 * Converts a relative URL into an absolute URL using [[baseUrl]].
167 * 将一个相对URL转换为绝对URL
168 * @param string $url the relative URL to be converted.要转换的相对URL
169 * @return string the absolute URL 替换后的绝对URL
170 * @throws InvalidConfigException if [[baseUrl]] is not set
171 */
172 public function getUrl($url)
173 {
174 if (($baseUrl = $this->getBaseUrl()) !== null) {//URL存在，进行转换
175 return $baseUrl . '/' . ltrim($url, '/');
176 } else {//不存在抛出异常
177 throw new InvalidConfigException('The "baseUrl" property must be set.');
178 }
179 }
180
181 /**
182 * Converts a relative file path into an absolute one using [[basePath]].
183 * 通过相对路径生成绝对路径
184 * @param string $path the relative file path to be converted. 要转换的相对文件路径。
185 * @return string the absolute file path 转换后的绝对路径
186 * @throws InvalidConfigException if [[baseUrl]] is not set
187 */
188 public function getPath($path)
189 {
190 if (($basePath = $this->getBasePath()) !== null) {
191 //返回拼接的路径
192 return $basePath . DIRECTORY_SEPARATOR . ltrim($path, '/\\');
193 } else {
194 throw new InvalidConfigException('The "basePath" property must be set.');
195 }
196 }
197 }
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