243 lines
7.7 KiB
PHP
243 lines
7.7 KiB
PHP
<?php
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/**
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* CFileCache 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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* CFileCache provides a file-based caching mechanism.
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*
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* For each data value being cached, CFileCache will use store it in a separate file
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* under {@link cachePath} which defaults to 'protected/runtime/cache'.
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* CFileCache will perform garbage collection automatically to remove expired cache files.
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*
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* See {@link CCache} manual for common cache operations that are supported by CFileCache.
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*
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* @property integer $gCProbability The probability (parts per million) that garbage collection (GC) should be performed
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* when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance.
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*
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* @author Qiang Xue <qiang.xue@gmail.com>
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* @package system.caching
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*/
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class CFileCache extends CCache
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{
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/**
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* @var string the directory to store cache files. Defaults to null, meaning
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* using 'protected/runtime/cache' as the directory.
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*/
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public $cachePath;
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/**
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* @var string cache file suffix. Defaults to '.bin'.
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*/
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public $cacheFileSuffix='.bin';
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/**
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* @var integer the level of sub-directories to store cache files. Defaults to 0,
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* meaning no sub-directories. If the system has huge number of cache files (e.g. 10K+),
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* you may want to set this value to be 1 or 2 so that the file system is not over burdened.
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* The value of this property should not exceed 16 (less than 3 is recommended).
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*/
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public $directoryLevel=0;
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/**
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* @var boolean whether cache entry expiration time should be embedded into a physical file.
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* Defaults to false meaning that the file modification time will be used to store expire value.
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* True value means that first ten bytes of the file would be reserved and used to store expiration time.
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* On some systems PHP is not allowed to change file modification time to be in future even with 777
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* permissions, so this property could be useful in this case.
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* @since 1.1.14
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*/
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public $embedExpiry=false;
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private $_gcProbability=100;
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private $_gced=false;
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/**
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* Initializes this application component.
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* This method is required by the {@link IApplicationComponent} interface.
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*/
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public function init()
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{
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parent::init();
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if($this->cachePath===null)
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$this->cachePath=Yii::app()->getRuntimePath().DIRECTORY_SEPARATOR.'cache';
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if(!is_dir($this->cachePath))
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mkdir($this->cachePath,0777,true);
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}
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/**
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* @return integer the probability (parts per million) that garbage collection (GC) should be performed
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* when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance.
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*/
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public function getGCProbability()
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{
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return $this->_gcProbability;
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}
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/**
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* @param integer $value the probability (parts per million) that garbage collection (GC) should be performed
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* when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance.
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* This number should be between 0 and 1000000. A value 0 meaning no GC will be performed at all.
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*/
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public function setGCProbability($value)
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{
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$value=(int)$value;
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if($value<0)
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$value=0;
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if($value>1000000)
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$value=1000000;
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$this->_gcProbability=$value;
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}
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/**
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* Deletes all values from cache.
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* This is the implementation of the method declared in the parent class.
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* @return boolean whether the flush operation was successful.
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* @since 1.1.5
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*/
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protected function flushValues()
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{
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$this->gc(false);
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return true;
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}
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/**
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* Retrieves a value from cache with a specified key.
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* This is the implementation of the method declared in the parent class.
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* @param string $key a unique key identifying the cached value
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* @return string|boolean the value stored in cache, false if the value is not in the cache or expired.
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*/
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protected function getValue($key)
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{
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$cacheFile=$this->getCacheFile($key);
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if(($time=$this->filemtime($cacheFile))>time())
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return @file_get_contents($cacheFile,false,null,$this->embedExpiry ? 10 : -1);
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elseif($time>0)
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@unlink($cacheFile);
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return false;
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}
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/**
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* Stores a value identified by a key in cache.
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* This is the implementation of the method declared in the parent class.
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*
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* @param string $key the key identifying the value to be cached
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* @param string $value the value to be cached
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* @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
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* @return boolean true if the value is successfully stored into cache, false otherwise
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*/
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protected function setValue($key,$value,$expire)
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{
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if(!$this->_gced && mt_rand(0,1000000)<$this->_gcProbability)
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{
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$this->gc();
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$this->_gced=true;
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}
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if($expire<=0)
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$expire=31536000; // 1 year
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$expire+=time();
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$cacheFile=$this->getCacheFile($key);
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if($this->directoryLevel>0)
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@mkdir(dirname($cacheFile),0777,true);
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if(@file_put_contents($cacheFile,$this->embedExpiry ? $expire.$value : $value,LOCK_EX)!==false)
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{
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@chmod($cacheFile,0777);
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return $this->embedExpiry ? true : @touch($cacheFile,$expire);
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}
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else
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return false;
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}
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/**
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* Stores a value identified by a key into cache if the cache does not contain this key.
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* This is the implementation of the method declared in the parent class.
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*
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* @param string $key the key identifying the value to be cached
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* @param string $value the value to be cached
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* @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
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* @return boolean true if the value is successfully stored into cache, false otherwise
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*/
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protected function addValue($key,$value,$expire)
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{
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$cacheFile=$this->getCacheFile($key);
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if($this->filemtime($cacheFile)>time())
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return false;
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return $this->setValue($key,$value,$expire);
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}
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/**
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* Deletes a value with the specified key from cache
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* This is the implementation of the method declared in the parent class.
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* @param string $key the key of the value to be deleted
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* @return boolean if no error happens during deletion
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*/
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protected function deleteValue($key)
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{
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$cacheFile=$this->getCacheFile($key);
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return @unlink($cacheFile);
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}
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/**
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* Returns the cache file path given the cache key.
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* @param string $key cache key
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* @return string the cache file path
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*/
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protected function getCacheFile($key)
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{
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if($this->directoryLevel>0)
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{
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$base=$this->cachePath;
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for($i=0;$i<$this->directoryLevel;++$i)
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{
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if(($prefix=substr($key,$i+$i,2))!==false)
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$base.=DIRECTORY_SEPARATOR.$prefix;
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}
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return $base.DIRECTORY_SEPARATOR.$key.$this->cacheFileSuffix;
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}
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else
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return $this->cachePath.DIRECTORY_SEPARATOR.$key.$this->cacheFileSuffix;
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}
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/**
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* Removes expired cache files.
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* @param boolean $expiredOnly whether only expired cache files should be removed.
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* If false, all cache files under {@link cachePath} will be removed.
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* @param string $path the path to clean with. If null, it will be {@link cachePath}.
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*/
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public function gc($expiredOnly=true,$path=null)
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{
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if($path===null)
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$path=$this->cachePath;
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if(($handle=opendir($path))===false)
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return;
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while(($file=readdir($handle))!==false)
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{
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if($file[0]==='.')
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continue;
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$fullPath=$path.DIRECTORY_SEPARATOR.$file;
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if(is_dir($fullPath))
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$this->gc($expiredOnly,$fullPath);
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elseif($expiredOnly && $this->filemtime($fullPath)<time() || !$expiredOnly)
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@unlink($fullPath);
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}
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closedir($handle);
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}
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/**
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* Returns cache file modification time. {@link $embedExpiry} aware.
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* @param string $path to the file, modification time to be retrieved from.
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* @return integer file modification time.
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*/
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private function filemtime($path)
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{
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if($this->embedExpiry)
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return (int)@file_get_contents($path,false,null,0,10);
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else
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return @filemtime($path);
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}
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}
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