<?php
/**
* File Storage engine for cache
*
*
* PHP 5
*
* CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
* Copyright 2005-2010, Cake Software Foundation, Inc. (http://cakefoundation.org)
*
* Licensed under The MIT License
* Redistributions of files must retain the above copyright notice.
*
* @copyright Copyright 2005-2010, Cake Software Foundation, Inc. (http://cakefoundation.org)
* @link http://cakephp.org CakePHP(tm) Project
* @package cake.libs.cache
* @since CakePHP(tm) v 1.2.0.4933
* @license MIT License (http://www.opensource.org/licenses/mit-license.php)
*/
/**
* File Storage engine for cache
*
* @todo use the File and Folder classes (if it's not a too big performance hit)
* @package cake.libs.cache
*/
class FileEngine extends CacheEngine {
/**
* Instance of SplFileObject class
*
* @var _File
* @access protected
*/
protected $_File = null;
/**
* Settings
*
* - path = absolute path to cache directory, default => CACHE
* - prefix = string prefix for filename, default => cake_
* - lock = enable file locking on write, default => false
* - serialize = serialize the data, default => true
*
* @var array
* @see CacheEngine::__defaults
* @access public
*/
public $settings = array();
/**
* True unless FileEngine::__active(); fails
*
* @var boolean
* @access protected
*/
protected $_init = true;
/**
* Initialize the Cache Engine
*
* Called automatically by the cache frontend
* To reinitialize the settings call Cache::engine('EngineName', [optional] settings = array());
*
* @param array $setting array of setting for the engine
* @return boolean True if the engine has been successfully initialized, false if not
*/
public function init($settings = array()) {
parent::init(array_merge(
array(
'engine' => 'File', 'path' => CACHE, 'prefix'=> 'cake_', 'lock'=> false,
'serialize'=> true, 'isWindows' => false
),
$settings
));
if (DS === '\\') {
$this->settings['isWindows'] = true;
}
if (substr($this->settings['path'], -1) !== DS) {
$this->settings['path'] .= DS;
}
return $this->_active();
}
/**
* Garbage collection. Permanently remove all expired and deleted data
*
* @return boolean True if garbage collection was succesful, false on failure
*/
public function gc() {
return $this->clear(true);
}
/**
* Write data for key into cache
*
* @param string $key Identifier for the data
* @param mixed $data Data to be cached
* @param mixed $duration How long to cache the data, in seconds
* @return boolean True if the data was succesfully cached, false on failure
*/
public function write($key, $data, $duration) {
if ($data === '' || !$this->_init) {
return false;
}
if ($this->_setKey($key, true) === false) {
return false;
}
$lineBreak = "\n";
if ($this->settings['isWindows']) {
$lineBreak = "\r\n";
}
if (!empty($this->settings['serialize'])) {
if ($this->settings['isWindows']) {
$data = str_replace('\\', '\\\\\\\\', serialize($data));
} else {
$data = serialize($data);
}
}
if ($this->settings['lock']) {
$this->_File->flock(LOCK_EX);
}
$expires = time() + $duration;
$contents = $expires . $lineBreak . $data . $lineBreak;
$success = $this->_File->ftruncate(0) && $this->_File->fwrite($contents);
if ($this->settings['lock']) {
$this->_File->flock(LOCK_UN);
}
$this->_File = null;
return $success;
}
/**
* Read a key from the cache
*
* @param string $key Identifier for the data
* @return mixed The cached data, or false if the data doesn't exist, has expired, or if there was an error fetching it
*/
public function read($key) {
if (!$this->_init || $this->_setKey($key) === false) {
return false;
}
if ($this->settings['lock']) {
$this->_File->flock(LOCK_SH);
}
$this->_File->rewind();
$time = time();
$cachetime = intval($this->_File->current());
if ($cachetime !== false && ($cachetime < $time || ($time + $this->settings['duration']) < $cachetime)) {
return false;
}
$data = '';
$this->_File->next();
while ($this->_File->valid()) {
$data .= $this->_File->current();
$this->_File->next();
}
if ($this->settings['lock']) {
$this->_File->flock(LOCK_UN);
}
$data = trim($data);
if ($data !== '' && !empty($this->settings['serialize'])) {
if ($this->settings['isWindows']) {
$data = str_replace('\\\\\\\\', '\\', $data);
}
$data = unserialize((string)$data);
}
return $data;
}
/**
* Delete a key from the cache
*
* @param string $key Identifier for the data
* @return boolean True if the value was successfully deleted, false if it didn't exist or couldn't be removed
*/
public function delete($key) {
if ($this->_setKey($key) === false || !$this->_init) {
return false;
}
$path = $this->_File->getRealPath();
$this->_File = null;
return unlink($path);
}
/**
* Delete all values from the cache
*
* @param boolean $check Optional - only delete expired cache items
* @return boolean True if the cache was succesfully cleared, false otherwise
*/
public function clear($check) {
if (!$this->_init) {
return false;
}
$dir = dir($this->settings['path']);
if ($check) {
$now = time();
$threshold = $now - $this->settings['duration'];
}
$prefixLength = strlen($this->settings['prefix']);
while (($entry = $dir->read()) !== false) {
if (substr($entry, 0, $prefixLength) !== $this->settings['prefix']) {
continue;
}
if ($this->_setKey($entry) === false) {
continue;
}
if ($check) {
$mtime = $this->_File->getMTime();
if ($mtime > $threshold) {
continue;
}
$expires = (int)$this->_File->current();
if ($expires > $now) {
continue;
}
}
$path = $this->_File->getRealPath();
$this->_File = null;
unlink($path);
}
$dir->close();
return true;
}
/**
* Not implemented
*
* @return void
* @throws CacheException
*/
public function decrement($key, $offset = 1) {
throw new CacheException(__('Files cannot be atomically decremented.'));
}
/**
* Not implemented
*
* @return void
* @throws CacheException
*/
public function increment($key, $offset = 1) {
throw new CacheException(__('Files cannot be atomically incremented.'));
}
/**
* Sets the current cache key this class is managing
*
* @param string $key The key
* @param boolean $createKey Whether the key should be created if it doesn't exists, or not
* @return boolean true if the cache key could be set, false otherwise
* @access protected
*/
protected function _setKey($key, $createKey = false) {
$path = new SplFileInfo($this->settings['path'] . $key);
if (!$createKey && !$path->isFile()) {
return false;
}
$old = umask(0);
if (empty($this->_File) || $this->_File->getBaseName() !== $key) {
$this->_File = $path->openFile('a+');
}
umask($old);
return true;
}
/**
* Determine is cache directory is writable
*
* @return boolean
* @access protected
*/
protected function _active() {
$dir = new SplFileInfo($this->settings['path']);
if ($this->_init && !($dir->isDir() && $dir->isWritable())) {
$this->_init = false;
trigger_error(__('%s is not writable', $this->settings['path']), E_USER_WARNING);
return false;
}
return true;
}
}