yii2源码学习笔记(十九),yii2源码学习笔记_PHP教程
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2022-06-13 09:41:18
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yii2源码学习笔记(十九),yii2源码学习笔记
view剩余代码
1 /** 2 * @return string|boolean the view file currently being rendered. False if no view file is being rendered. 3 * 当前正在渲染的视图文件 4 */ 5 public function getViewFile() 6 { 7 return end($this->_viewFiles); 8 } 9 10 /** 11 * This method is invoked right before [[renderFile()]] renders a view file. 12 * The default implementation will trigger the [[EVENT_BEFORE_RENDER]] event. 13 * 前置事件,执行[renderFile()]时被调用,默认触发[[EVENT_BEFORE_RENDER]]事件 14 * If you override this method, make sure you call the parent implementation first. 15 * @param string $viewFile the view file to be rendered. 要渲染的视图文件。 16 * @param array $params the parameter array passed to the [[render()]] method. 17 * 参数数组传递到[render()]方法。 18 * @return boolean whether to continue rendering the view file. 是否继续渲染视图文件。 19 */ 20 public function beforeRender($viewFile, $params) 21 { 22 $event = new ViewEvent([//实例化ViewEvent 23 'viewFile' => $viewFile, 24 'params' => $params, 25 ]); 26 $this->trigger(self::EVENT_BEFORE_RENDER, $event);//触发[EVENT_BEFORE_RENDER]事件 27 28 return $event->isValid;//判断是否继续渲染文件 29 } 30 31 /** 32 * This method is invoked right after [[renderFile()]] renders a view file. 33 * The default implementation will trigger the [[EVENT_AFTER_RENDER]] event. 34 * 后置事件,在执行[renderFile()]方法后被调用,默认触发[[EVENT_AFTER_RENDER]]事件 35 * If you override this method, make sure you call the parent implementation first. 36 * @param string $viewFile the view file being rendered.要渲染的视图文件。 37 * @param array $params the parameter array passed to the [[render()]] method. 38 * 参数数组传递到[render()]方法。 39 * @param string $output the rendering result of the view file. Updates to this parameter 40 * will be passed back and returned by [[renderFile()]]. 41 * 返回视图渲染的结果 42 */ 43 public function afterRender($viewFile, $params, &$output) 44 { 45 if ($this->hasEventHandlers(self::EVENT_AFTER_RENDER)) {//判断[EVENT_AFTER_RENDER]事件是否存在 46 $event = new ViewEvent([ 47 'viewFile' => $viewFile, 48 'params' => $params, 49 'output' => $output, 50 ]); 51 //触发[EVENT_AFTER_RENDER]事件 52 $this->trigger(self::EVENT_AFTER_RENDER, $event); 53 $output = $event->output;//返回结果 54 } 55 } 56 57 /** 58 * Renders a view file as a PHP script. 59 * 返回一个视图文件当作PHP脚本 60 * This method treats the view file as a PHP script and includes the file. 61 * It extracts the given parameters and makes them available in the view file. 62 * The method captures the output of the included view file and returns it as a string. 63 * 将传入的参数转换为变量,包含并执行view文件,返回执行结果 64 * This method should mainly be called by view renderer or [[renderFile()]]. 65 * 66 * @param string $_file_ the view file. 视图文件 67 * @param array $_params_ the parameters (name-value pairs) that will be extracted and made available in the view file. 68 * @return string the rendering result 执行结果 69 */ 70 public function renderPhpFile($_file_, $_params_ = []) 71 { 72 ob_start(); //打开输出缓冲 73 ob_implicit_flush(false); //关闭缓冲区 74 extract($_params_, EXTR_OVERWRITE);// 将一个数组转换为变量使用 75 require($_file_); 76 77 return ob_get_clean();//得到缓冲区的内容并清除当前输出缓冲 78 } 79 80 /** 81 * Renders dynamic content returned by the given PHP statements. 渲染动态内容 82 * This method is mainly used together with content caching (fragment caching and page caching) 83 * 用来聚合缓存的内容 84 * when some portions of the content (called *dynamic content*) should not be cached. 85 * The dynamic content must be returned by some PHP statements. 86 * 渲染某些被PHP语句返回的动态内容 87 * @param string $statements the PHP statements for generating the dynamic content.生成动态内容的PHP语句。 88 * @return string the placeholder of the dynamic content, or the dynamic content if there is no 89 * active content cache currently. 动态内容占位符 如果当前没有有效的内容缓存,调用evaluateDynamicContent输出 90 */ 91 public function renderDynamic($statements) 92 { 93 if (!empty($this->cacheStack)) {//动态内容的列表不为空 94 $n = count($this->dynamicPlaceholders);//统计动态内容条数 95 $placeholder = "";//生成占位符 96 $this->addDynamicPlaceholder($placeholder, $statements);//添加动态内容占位符 97 98 return $placeholder; 99 } else {//没有有效缓存 执行传入的PHP语句,返回执行结果 100 return $this->evaluateDynamicContent($statements); 101 } 102 } 103 104 /** 105 * Adds a placeholder for dynamic content. 添加一个动态内容占位符 106 * This method is internally used. 内部使用 107 * @param string $placeholder the placeholder name 占位符名称 108 * @param string $statements the PHP statements for generating the dynamic content 109 * 生成动态内容的PHP语句 110 */ 111 public function addDynamicPlaceholder($placeholder, $statements) 112 { 113 foreach ($this->cacheStack as $cache) { 114 $cache->dynamicPlaceholders[$placeholder] = $statements;//添加动态内容占位符 115 } 116 $this->dynamicPlaceholders[$placeholder] = $statements;//给当前视图添加动态内容占位符 117 } 118 119 /** 120 * Evaluates the given PHP statements. 给定的PHP语句的值 121 * This method is mainly used internally to implement dynamic content feature.内部使用实现动态内容功能 122 * @param string $statements the PHP statements to be evaluated. PHP语句进行计算 123 * @return mixed the return value of the PHP statements. PHP语句的值 124 */ 125 public function evaluateDynamicContent($statements) 126 { 127 return eval($statements); 128 } 129 130 /** 131 * Begins recording a block. 132 * This method is a shortcut to beginning [[Block]] 133 * 数据块开始的标记,该方法是开始[Block]的快捷方式 134 * 数据块可以在一个地方指定视图内容在另一个地方显示,通常和布局一起使用 135 * @param string $id the block ID. 数据块标识 136 * @param boolean $renderInPlace whether to render the block content in place. 是否渲染块内容。 137 * Defaults to false, meaning the captured block will not be displayed. 138 * @return Block the Block widget instance 数据块部件实例 139 */ 140 public function beginBlock($id, $renderInPlace = false) 141 { 142 return Block::begin([ 143 'id' => $id,//数据块唯一标识 144 'renderInPlace' => $renderInPlace,//是否显示标识 145 'view' => $this, 146 ]); 147 } 148 149 /** 150 * Ends recording a block. 数据块结束标识 151 */ 152 public function endBlock() 153 { 154 Block::end(); 155 } 156 157 /** 158 * Begins the rendering of content that is to be decorated by the specified view. 159 * This method can be used to implement nested layout. For example, a layout can be embedded 160 * in another layout file specified as '@app/views/layouts/base.php' like the following: 161 * 开始指定的view渲染内容,用来实现嵌套布局,传入的第一个参数为布局文件的路径 162 * ~~~ 163 * beginContent('@app/views/layouts/base.php'); ?> 164 * ...layout content here... 165 * endContent(); ?> 166 * ~~~ 167 * 168 * @param string $viewFile the view file that will be used to decorate the content enclosed by this widget. 169 * This can be specified as either the view file path or path alias.布局文件的路径或路径别名。 170 * @param array $params the variables (name => value) to be extracted and made available in the decorative view. 171 * 可以在视图中运用的参数 172 * @return ContentDecorator the ContentDecorator widget instance 部件实例 173 * @see ContentDecorator 174 */ 175 public function beginContent($viewFile, $params = []) 176 { 177 return ContentDecorator::begin([ 178 'viewFile' => $viewFile, 179 'params' => $params, 180 'view' => $this, 181 ]); 182 } 183 184 /** 185 * Ends the rendering of content.结束渲染内容 186 */ 187 public function endContent() 188 { 189 ContentDecorator::end(); 190 } 191 192 /** 193 * Begins fragment caching. 开始片段缓存 194 * This method will display cached content if it is available. 195 * If not, it will start caching and would expect an [[endCache()]] 196 * call to end the cache and save the content into cache. 197 * 展示可用的缓存内容,否则将开始缓存内容直到出现[endCache()]方法 198 * A typical usage of fragment caching is as follows, 199 * 200 * ~~~ 201 * if ($this->beginCache($id)) { 202 * // ...generate content here 203 * $this->endCache(); 204 * } 205 * ~~~ 206 * 207 * @param string $id a unique ID identifying the fragment to be cached.缓存片段的唯一标识 208 * @param array $properties initial property values for [[FragmentCache]]初始属性[FragmentCache] 209 * @return boolean whether you should generate the content for caching. 是否生成缓存的内容。 210 * False if the cached version is available. 211 */ 212 public function beginCache($id, $properties = []) 213 { 214 $properties['id'] = $id; //片段标识 215 $properties['view'] = $this; //调用初始化属性 216 /* @var $cache FragmentCache */ 217 $cache = FragmentCache::begin($properties); 218 if ($cache->getCachedContent() !== false) { 219 $this->endCache();//从缓存中读取到了缓存的内容,则渲染内容并返回 false,不再进行缓存 220 221 return false; 222 } else { 223 return true; 224 } 225 } 226 227 /** 228 * Ends fragment caching. 结束片段缓存 229 */ 230 public function endCache() 231 { 232 FragmentCache::end(); 233 } 234 235 /** 236 * Marks the beginning of a page.页面开始标记 237 */ 238 public function beginPage() 239 { 240 ob_start(); //打开输出缓冲 241 ob_implicit_flush(false);//关闭缓冲区 242 243 $this->trigger(self::EVENT_BEGIN_PAGE); 244 } 245 246 /** 247 * Marks the ending of a page. 页面结束标记 248 */ 249 public function endPage() 250 { 251 $this->trigger(self::EVENT_END_PAGE); 252 ob_end_flush();//关闭输出缓冲区 253 }