file.php

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<?php
/* SVN FILE: $Id: file.php 8195 2009-06-16 20:14:50Z gwoo $ */
/**
 * File Storage engine for cache
 *
 *
 * PHP versions 4 and 5
 *
 * CakePHP(tm) :  Rapid Development Framework (http://www.cakephp.org)
 * Copyright 2005-2008, Cake Software Foundation, Inc. (http://www.cakefoundation.org)
 *
 * Licensed under The MIT License
 * Redistributions of files must retain the above copyright notice.
 *
 * @filesource
 * @copyright     Copyright 2005-2008, Cake Software Foundation, Inc. (http://www.cakefoundation.org)
 * @link          http://www.cakefoundation.org/projects/info/cakephp CakePHP(tm) Project
 * @package       cake
 * @subpackage    cake.cake.libs.cache
 * @since         CakePHP(tm) v 1.2.0.4933
 * @version       $Revision: 8195 $
 * @modifiedby    $LastChangedBy: gwoo $
 * @lastmodified  $Date: 2009-06-16 16:14:50 -0400 (Tue, 16 Jun 2009) $
 * @license       http://www.opensource.org/licenses/mit-license.php The MIT License
 */
/**
 * File Storage engine for cache
 *
 * @todo use the File and Folder classes (if it's not a too big performance hit)
 * @package       cake
 * @subpackage    cake.cake.libs.cache
 */
class FileEngine extends CacheEngine {
/**
 * Instance of File class
 *
 * @var File
 * @access private
 */
    var $__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
 */
    var $settings = array();
/**
 * Set to true if FileEngine::init(); and FileEngine::__active(); do not fail.
 *
 * @var boolean
 * @access private
 */
    var $__active = false;
/**
 * True unless FileEngine::__active(); fails
 *
 * @var boolean
 * @access private
 */
    var $__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 $setting array of setting for the engine
 * @return boolean True if the engine has been successfully initialized, false if not
 * @access public
 */
    function init($settings = array()) {
        parent::init(array_merge(
            array(
                'engine' => 'File', 'path' => CACHE, 'prefix'=> 'cake_', 'lock'=> false,
                'serialize'=> true, 'isWindows' => false
            ),
            $settings
        ));
        if (!isset($this->__File)) {
            if (!class_exists('File')) {
                require LIBS . 'file.php';
            }
            $this->__File =& new File($this->settings['path'] . DS . 'cake');
        }

        if (DIRECTORY_SEPARATOR === '\\') {
            $this->settings['isWindows'] = true;
        }

        $this->settings['path'] = $this->__File->Folder->cd($this->settings['path']);
        if (empty($this->settings['path'])) {
            return false;
        }
        return $this->__active();
    }
/**
 * Garbage collection. Permanently remove all expired and deleted data
 *
 * @return boolean True if garbage collection was succesful, false on failure
 * @access 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 $duration How long to cache the data, in seconds
 * @return boolean True if the data was succesfully cached, false on failure
 * @access public
 */
    function write($key, &$data, $duration) {
        if ($data === '' || !$this->__init) {
            return false;
        }

        if ($this->__setKey($key) === 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->lock = true;
        }
        $expires = time() + $duration;
        $contents = $expires . $lineBreak . $data . $lineBreak;
        $success = $this->__File->write($contents);
        $this->__File->close();
        return $success;
    }
/**
 * Read a key from the cache
 *
 * @param string $key Identifier for the data
 * @return mixed The cached data, or false if the data doesn't exist, has expired, or if there was an error fetching it
 * @access public
 */
    function read($key) {
        if ($this->__setKey($key) === false || !$this->__init || !$this->__File->exists()) {
            return false;
        }
        if ($this->settings['lock']) {
            $this->__File->lock = true;
        }
        $time = time();
        $cachetime = intval($this->__File->read(11));

        if ($cachetime !== false && ($cachetime < $time || ($time + $this->settings['duration']) < $cachetime)) {
            $this->__File->close();
            return false;
        }
        $data = $this->__File->read(true);

        if ($data !== '' && !empty($this->settings['serialize'])) {
            if ($this->settings['isWindows']) {
                $data = str_replace('\\\\\\\\', '\\', $data);
            }
            $data = unserialize((string)$data);
        }
        $this->__File->close();
        return $data;
    }
/**
 * Delete a key from the cache
 *
 * @param string $key Identifier for the data
 * @return boolean True if the value was successfully deleted, false if it didn't exist or couldn't be removed
 * @access public
 */
    function delete($key) {
        if ($this->__setKey($key) === false || !$this->__init) {
            return false;
        }
        return $this->__File->delete();
    }
/**
 * Delete all values from the cache
 *
 * @param boolean $check Optional - only delete expired cache items
 * @return boolean True if the cache was succesfully cleared, false otherwise
 * @access public
 */
    function clear($check) {
        if (!$this->__init) {
            return false;
        }
        $dir = dir($this->settings['path']);
        if ($check) {
            $now = time();
            $threshold = $now - $this->settings['duration'];
        }
        while (($entry = $dir->read()) !== false) {
            if ($this->__setKey($entry) === false) {
                continue;
            }
            if ($check) {
                $mtime = $this->__File->lastChange();

                if ($mtime === false || $mtime > $threshold) {
                    continue;
                }

                $expires = $this->__File->read(11);
                $this->__File->close();

                if ($expires > $now) {
                    continue;
                }
            }
            $this->__File->delete();
        }
        $dir->close();
        return true;
    }
/**
 * Get absolute file for a given key
 *
 * @param string $key The key
 * @return mixed Absolute cache file for the given key or false if erroneous
 * @access private
 */
    function __setKey($key) {
        $this->__File->Folder->cd($this->settings['path']);
        if ($key !== $this->__File->name) {
            $this->__File->name = $key;
            $this->__File->path = null;
        }
        if (!$this->__File->Folder->inPath($this->__File->pwd(), true)) {
            return false;
        }
    }
/**
 * Determine is cache directory is writable
 *
 * @return boolean
 * @access private
 */
    function __active() {
        if (!$this->__active && $this->__init && !is_writable($this->settings['path'])) {
            $this->__init = false;
            trigger_error(sprintf(__('%s is not writable', true), $this->settings['path']), E_USER_WARNING);
        } else {
            $this->__active = true;
        }
        return true;
    }
}
?>

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