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47 lines
1.3 KiB
47 lines
1.3 KiB
<?php |
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/** |
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* ExpressionDependency class file. |
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* |
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* @link http://www.yiiframework.com/ |
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* @copyright Copyright © 2008-2012 Yii Software LLC |
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* @license http://www.yiiframework.com/license/ |
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*/ |
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namespace yii\caching; |
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/** |
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* ExpressionDependency represents a dependency based on the result of a PHP expression. |
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* |
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* ExpressionDependency will use `eval()` to evaluate the PHP expression. |
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* The dependency is reported as unchanged if and only if the result of the expression is |
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* the same as the one evaluated when storing the data to cache. |
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* |
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* @author Qiang Xue <qiang.xue@gmail.com> |
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* @since 2.0 |
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*/ |
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class ExpressionDependency extends Dependency |
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{ |
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/** |
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* @var string the PHP expression whose result is used to determine the dependency. |
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*/ |
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public $expression; |
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/** |
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* Constructor. |
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* @param string $expression the PHP expression whose result is used to determine the dependency. |
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*/ |
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public function __construct($expression = 'true') |
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{ |
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$this->expression = $expression; |
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} |
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/** |
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* Generates the data needed to determine if dependency has been changed. |
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* This method returns the result of the PHP expression. |
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* @return mixed the data needed to determine if dependency has been changed. |
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*/ |
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protected function generateDependencyData() |
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{ |
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return eval("return {$this->expression};"); |
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} |
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}
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