<?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;
        unlink( $file );
        return true;
    }
}
?>