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48 lines
1.7 KiB
PHP
48 lines
1.7 KiB
PHP
<?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 $expression = 'true';
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/**
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* @var mixed custom parameters associated with this dependency. You may get the value
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* of this property in [[expression]] using `$this->params`.
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*/
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public $params;
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/**
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* 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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