|
|
|
<?php
|
|
|
|
/**
|
|
|
|
* ExpressionDependency class file.
|
|
|
|
*
|
|
|
|
* @link http://www.yiiframework.com/
|
|
|
|
* @copyright Copyright © 2008-2012 Yii Software LLC
|
|
|
|
* @license http://www.yiiframework.com/license/
|
|
|
|
*/
|
|
|
|
|
|
|
|
namespace yii\caching;
|
|
|
|
|
|
|
|
/**
|
|
|
|
* ExpressionDependency represents a dependency based on the result of a PHP expression.
|
|
|
|
*
|
|
|
|
* ExpressionDependency performs dependency checking based on the
|
|
|
|
* result of a PHP {@link expression}.
|
|
|
|
* The dependency is reported as unchanged if and only if the result is
|
|
|
|
* the same as the one evaluated when storing the data to cache.
|
|
|
|
*
|
|
|
|
* @author Qiang Xue <qiang.xue@gmail.com>
|
|
|
|
* @since 2.0
|
|
|
|
*/
|
|
|
|
class ExpressionDependency extends Dependency
|
|
|
|
{
|
|
|
|
/**
|
|
|
|
* @var string the PHP expression whose result is used to determine the dependency.
|
|
|
|
* The expression can also be a valid PHP callback,
|
|
|
|
* including class method name (array(ClassName/Object, MethodName)),
|
|
|
|
* or anonymous function (PHP 5.3.0+). The function/method will be passed with a
|
|
|
|
* parameter which is the dependency object itself.
|
|
|
|
*/
|
|
|
|
public $expression;
|
|
|
|
|
|
|
|
/**
|
|
|
|
* Constructor.
|
|
|
|
* @param string $expression the PHP expression whose result is used to determine the dependency.
|
|
|
|
*/
|
|
|
|
public function __construct($expression = 'true')
|
|
|
|
{
|
|
|
|
$this->expression = $expression;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* Generates the data needed to determine if dependency has been changed.
|
|
|
|
* This method returns the result of the PHP expression.
|
|
|
|
* @return mixed the data needed to determine if dependency has been changed.
|
|
|
|
*/
|
|
|
|
protected function generateDependencyData()
|
|
|
|
{
|
|
|
|
return $this->evaluateExpression($this->expression);
|
|
|
|
}
|
|
|
|
}
|