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60 lines
2.2 KiB
60 lines
2.2 KiB
<?php |
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/** |
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* @link http://www.yiiframework.com/ |
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* @copyright Copyright (c) 2008 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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* A PHP expression can be any PHP code that has a value. To learn more about what an expression is, |
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* please refer to the [php manual](http://www.php.net/manual/en/language.expressions.php). |
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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 string representation of a PHP expression whose result is used to determine the dependency. |
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* A PHP expression can be any PHP code that evaluates to a value. To learn more about what an expression is, |
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* please refer to the [php manual](http://www.php.net/manual/en/language.expressions.php). |
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*/ |
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public $expression; |
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/** |
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* @var mixed custom parameters associated with this dependency. You may get the value |
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* of this property in [[expression]] using `$this->params`. |
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*/ |
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public $params; |
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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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* @param mixed $params the custom parameters associated with this dependency |
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* @param array $config name-value pairs that will be used to initialize the object properties |
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*/ |
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public function __construct($expression = 'true', $params = null, $config = array()) |
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{ |
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$this->expression = $expression; |
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$this->params = $params; |
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parent::__construct($config); |
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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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* @param Cache $cache the cache component that is currently evaluating this dependency |
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* @return mixed the data needed to determine if dependency has been changed. |
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*/ |
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protected function generateDependencyData($cache) |
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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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