<?php
/**
 * Caching: cache driver file
 *
 * $Id$
 *
 * @author gERD Schaufelberger <gerd@php-tools.net>
 * @license PHP License
 * @package WB
 * @subpackage base
 */

/**
 * load base class
 */
WBClass::load( 'WBCache_Driver' );

/**
 * Caching: cache driver file
 *
 * Stores everything in filesystem
 *
 * @version 0.1.2
 * @package WB
 * @subpackage base
 */
class WBCache_Driver_File extends WBCache_Driver
{
    /**
     * Cache Folder
     * @var string
     */
    protected $_cacheDir;

    /**
     * Constructor
     *
     * Load index file
     */
    public function __construct()
    {
        $this->_cacheDir    =   WBParam::get( 'wb/dir/base' ) . '/var/cache/general';
        if (!is_dir($this->_cacheDir)) {
            mkdir($this->_cacheDir, 0777, true);
            chmod($this->_cacheDir, 0777);
        }

        $file   =   $this->_cacheDir . '/_index';
        if (file_exists($file)) {
            $this->_index   =   unserialize(file_get_contents($file));
        }
    }
    
    /**
     * Destruct
     *
     * Save index file
     */
    public function __destruct()
    {
        $file   =   $this->_cacheDir . '/_index';
        
        $chmod  =   true;
        if (file_exists($file)) {
            $chmod  =   false;
        }
        file_put_contents($file, serialize($this->_index));
        if ($chmod) {
            chmod($file, 0666);
        }
    }

    /**
     * Fetch Cached Data
     *
     * @param string $id cache id
     * @return mixed return data or null if not cached yet
     */
    public function get($id)
    {
        $file   =   $this->_cacheDir . '/' . $id;
        if (!file_exists($file)) {
            return null;
        }
        
        $cnt    =   file_get_contents($file);
        return unserialize($cnt);
    }

    /**
     * Store Data in Cache
     *
     * @param string $id cache id
     * @return mixed return data or null if not cached yet
     */
    public function set($id, $data)
    {
        $cnt    =   serialize($data);
        $file   =   $this->_cacheDir . '/' . $id;

        $chmod  =   true;
        if (file_exists($file)) {
            $chmod  =   false;
        }
        
        file_put_contents($file, $cnt);
        
        if ($chmod) {
            chmod($file, 0666);
        }
        return true;
    }

    /**
     * Flush Cached Data
     *
     * @param string $id cache id
     * @return bool true on success
     */
    public function flush($id)
    {
        $file   =   $this->_cacheDir . '/' . $id;
        if (!file_exists($file)) {
            return true;
        }
        unlink($file);
        return true;
    }
}