117 lines
3.3 KiB
PHP
117 lines
3.3 KiB
PHP
<?php
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/**
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* CCacheDependency class file.
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*
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* @author Qiang Xue <qiang.xue@gmail.com>
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* @link http://www.yiiframework.com/
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* @copyright 2008-2013 Yii Software LLC
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* @license http://www.yiiframework.com/license/
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*/
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/**
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* CCacheDependency is the base class for cache dependency classes.
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*
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* CCacheDependency implements the {@link ICacheDependency} interface.
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* Child classes should override its {@link generateDependentData} for
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* actual dependency checking.
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*
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* @property boolean $hasChanged Whether the dependency has changed.
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* @property mixed $dependentData The data used to determine if dependency has been changed.
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* This data is available after {@link evaluateDependency} is called.
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*
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* @author Qiang Xue <qiang.xue@gmail.com>
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* @package system.caching.dependencies
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* @since 1.0
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*/
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class CCacheDependency extends CComponent implements ICacheDependency
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{
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/**
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* @var boolean Whether this dependency is reusable or not.
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* If set to true, dependent data for this cache dependency will only be generated once per request.
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* You can then use the same cache dependency for multiple separate cache calls on the same page
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* without the overhead of re-evaluating the dependency each time.
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* Defaults to false;
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* @since 1.1.11
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*/
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public $reuseDependentData=false;
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/**
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* @var array cached data for reusable dependencies.
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* @since 1.1.11
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*/
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private static $_reusableData=array();
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private $_hash;
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private $_data;
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/**
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* Evaluates the dependency by generating and saving the data related with dependency.
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* This method is invoked by cache before writing data into it.
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*/
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public function evaluateDependency()
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{
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if ($this->reuseDependentData)
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{
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$hash=$this->getHash();
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if(!isset(self::$_reusableData[$hash]['dependentData']))
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self::$_reusableData[$hash]['dependentData']=$this->generateDependentData();
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$this->_data=self::$_reusableData[$hash]['dependentData'];
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}
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else
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$this->_data=$this->generateDependentData();
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}
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/**
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* @return boolean whether the dependency has changed.
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*/
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public function getHasChanged()
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{
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if ($this->reuseDependentData)
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{
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$hash=$this->getHash();
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if(!isset(self::$_reusableData[$hash]['dependentData']))
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self::$_reusableData[$hash]['dependentData']=$this->generateDependentData();
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return self::$_reusableData[$hash]['dependentData']!=$this->_data;
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}
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else
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return $this->generateDependentData()!=$this->_data;
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}
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/**
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* @return mixed the data used to determine if dependency has been changed.
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* This data is available after {@link evaluateDependency} is called.
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*/
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public function getDependentData()
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{
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return $this->_data;
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}
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/**
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* Resets cached data for reusable dependencies.
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* @since 1.1.14
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*/
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public static function resetReusableData()
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{
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self::$_reusableData=array();
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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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* Derived classes should override this method to generate actual dependent data.
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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 generateDependentData()
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{
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return null;
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}
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/**
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* Generates a unique hash that identifies this cache dependency.
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* @return string the hash for this cache dependency
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*/
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private function getHash()
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{
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if($this->_hash===null)
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$this->_hash=sha1(serialize($this));
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return $this->_hash;
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}
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} |