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<?php
/**
* @link http://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/
namespace yii\caching;
use Yii;
/**
* FileCache implements a cache component using files.
*
* For each data value being cached, FileCache will store it in a separate file.
* The cache files are placed under [[cachePath]]. FileCache will perform garbage collection
* automatically to remove expired cache files.
*
* Please refer to [[Cache]] for common cache operations that are supported by FileCache.
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
class FileCache extends Cache
{
/**
* @var string the directory to store cache files. You may use path alias here.
* If not set, it will use the "cache" subdirectory under the application runtime path.
*/
public $cachePath = '@app/runtime/cache';
/**
* @var string cache file suffix. Defaults to '.bin'.
*/
public $cacheFileSuffix = '.bin';
/**
* @var integer the level of sub-directories to store cache files. Defaults to 1.
* If the system has huge number of cache files (e.g. one million), you may use a bigger value
* (usually no bigger than 3). Using sub-directories is mainly to ensure the file system
* is not over burdened with a single directory having too many files.
*/
public $directoryLevel = 1;
/**
* @var integer the probability (parts per million) that garbage collection (GC) should be performed
* when storing a piece of data in the cache. Defaults to 10, meaning 0.001% chance.
* This number should be between 0 and 1000000. A value 0 means no GC will be performed at all.
**/
public $gcProbability = 10;
/**
* Initializes this component by ensuring the existence of the cache path.
*/
public function init()
{
parent::init();
$this->cachePath = Yii::getAlias($this->cachePath);
if (!is_dir($this->cachePath)) {
mkdir($this->cachePath, 0777, true);
}
}
/**
* Retrieves a value from cache with a specified key.
* This is the implementation of the method declared in the parent class.
* @param string $key a unique key identifying the cached value
* @return string|boolean the value stored in cache, false if the value is not in the cache or expired.
*/
protected function getValue($key)
{
$cacheFile = $this->getCacheFile($key);
if (($time = @filemtime($cacheFile)) > time()) {
return @file_get_contents($cacheFile);
} else {
return false;
}
}
/**
* Stores a value identified by a key in cache.
* This is the implementation of the method declared in the parent class.
*
* @param string $key the key identifying the value to be cached
* @param string $value the value to be cached
* @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
* @return boolean true if the value is successfully stored into cache, false otherwise
*/
protected function setValue($key, $value, $expire)
{
if ($expire <= 0) {
$expire = 31536000; // 1 year
}
$expire += time();
$cacheFile = $this->getCacheFile($key);
if ($this->directoryLevel > 0) {
@mkdir(dirname($cacheFile), 0777, true);
}
if (@file_put_contents($cacheFile, $value, LOCK_EX) !== false) {
@chmod($cacheFile, 0777);
return @touch($cacheFile, $expire);
} else {
return false;
}
}
/**
* Stores a value identified by a key into cache if the cache does not contain this key.
* This is the implementation of the method declared in the parent class.
*
* @param string $key the key identifying the value to be cached
* @param string $value the value to be cached
* @param integer $expire the number of seconds in which the cached value will expire. 0 means never expire.
* @return boolean true if the value is successfully stored into cache, false otherwise
*/
protected function addValue($key, $value, $expire)
{
$cacheFile = $this->getCacheFile($key);
if (@filemtime($cacheFile) > time()) {
return false;
}
return $this->setValue($key, $value, $expire);
}
/**
* Deletes a value with the specified key from cache
* This is the implementation of the method declared in the parent class.
* @param string $key the key of the value to be deleted
* @return boolean if no error happens during deletion
*/
protected function deleteValue($key)
{
$cacheFile = $this->getCacheFile($key);
return @unlink($cacheFile);
}
/**
* Returns the cache file path given the cache key.
* @param string $key cache key
* @return string the cache file path
*/
protected function getCacheFile($key)
{
if ($this->directoryLevel > 0) {
$base = $this->cachePath;
for ($i = 0; $i < $this->directoryLevel; ++$i) {
if (($prefix = substr($key, $i + $i, 2)) !== false) {
$base .= DIRECTORY_SEPARATOR . $prefix;
}
}
return $base . DIRECTORY_SEPARATOR . $key . $this->cacheFileSuffix;
} else {
return $this->cachePath . DIRECTORY_SEPARATOR . $key . $this->cacheFileSuffix;
}
}
/**
* Deletes all values from cache.
* This is the implementation of the method declared in the parent class.
* @return boolean whether the flush operation was successful.
*/
protected function flushValues()
{
$this->gc(true, false);
return true;
}
/**
* Removes expired cache files.
* @param boolean $force whether to enforce the garbage collection regardless of [[gcProbability]].
* Defaults to false, meaning the actual deletion happens with the probability as specified by [[gcProbability]].
* @param boolean $expiredOnly whether to removed expired cache files only.
* If true, all cache files under [[cachePath]] will be removed.
*/
public function gc($force = false, $expiredOnly = true)
{
if ($force || mt_rand(0, 1000000) < $this->gcProbability) {
$this->gcRecursive($this->cachePath, $expiredOnly);
}
}
/**
* Recursively removing expired cache files under a directory.
* This method is mainly used by [[gc()]].
* @param string $path the directory under which expired cache files are removed.
* @param boolean $expiredOnly whether to only remove expired cache files. If false, all files
* under `$path` will be removed.
*/
protected function gcRecursive($path, $expiredOnly)
{
if (($handle = opendir($path)) !== false) {
while (($file = readdir($handle)) !== false) {
if ($file[0] === '.') {
continue;
}
$fullPath = $path . DIRECTORY_SEPARATOR . $file;
if (is_dir($fullPath)) {
$this->gcRecursive($fullPath, $expiredOnly);
if (!$expiredOnly) {
@rmdir($fullPath);
}
} elseif (!$expiredOnly || $expiredOnly && @filemtime($fullPath) < time()) {
@unlink($fullPath);
}
}
closedir($handle);
}
}
}