<?php
 
/*
Name: ObjectCache for WordPress
Description: Filesystem Backend for WP Object Cache.
Version: 0.1
URI: http://www.php-trivandrum.org
Author: Jiju Thomas Mathew

 
* Install this file to /wp-content/object-cache.php

Thanks to Ryan Boren for his original memcached code.
Thanks to Computer Guru of neosmart technologies, and his eAccelerator backend for the WP Object Cache, based on 
  which this no backend is worked out.
*/

	function wp_cache_add($key, $data, $flag = '', $expire = 0)
	{
		return wp_cache_set($key, $data, $flag, $expire);
	}

	function wp_cache_close()
	{
		return true;
	}

	function wp_cache_delete($id, $flag = '')
	{
		global $wp_object_cache;

		return $wp_object_cache->delete($id, $flag);
	}

	function wp_cache_flush()
	{
		global $wp_object_cache;

		return $wp_object_cache->flush();
	}

	function wp_cache_get($id, $flag = '')
	{
		global $wp_object_cache;

		return $wp_object_cache->get($id, $flag);
	}

	function wp_cache_init()
	{
		global $wp_object_cache;

		$wp_object_cache = new WP_Object_Cache();
	}

	function wp_cache_replace($key, $data, $flag = '', $expire = 0)
	{
		return wp_cache_set($key, $data, $flag, $expire);
	}

	function wp_cache_set($key, $data, $flag = '', $expire = 0)
	{
		global $wp_object_cache;

		return $wp_object_cache->set($key, $data, $flag, $expire);
	}

	class WP_Object_Cache {
		var $global_groups = array ('users', 'userlogins', 'usermeta');
		var $cache = array();

		function delete($id, $group = 'default')
		{
			$key = $this->key($id, $group);
	        	$result = @unlink($this->getkeystore($key));
			if ( $result )
					unset($this->cache[$key]);
			return $result;
		}

	function flush()
	{
		/* a bit too tricky.. will the overhead override the advantage ? */
		$fileglob = glob($this->getPrefix() . '.*');
		ob_start();
		if(is_array($fileglob))
			array_map('unlink', $fileglob);
		ob_get_clean();
		$this->cache = array();
		return true;
	}

	function get($id, $group = 'default')
	{
			$key = $this->key($id, $group);

			if ( isset($this->cache[$key]) )
				$value = $this->cache[$key];
			else
				$value = $this->fetch($key);

			$value = maybe_unserialize($value);

			if ( NULL === $value )
				$value = false;
			$this->cache[$key] = $value;
			return $value;
	}

	function set($id, $data, $group = 'default', $expire = 0)
	{
			$key = $this->key($id, $group);
			if ( is_resource($data) )
				return false;

			$data = maybe_serialize($data);

			$result = $this->store($key, $data, $expire);
			if ( $result )
				$this->cache[$key] = $data;

			return $result;
	}

	function key($key, $group)
	{
			global $blog_id;

			if ( empty($group) )
				$group = 'default';

			if (false !== array_search($group, $this->global_groups))
				$prefix = '';
			else
				$prefix = $blog_id . ':';

			return md5(ABSPATH . "$prefix$group:$key");
	}

	function stats()
	{
	}

	function fetch($key) {
	    $ksFile = $this->getkeystore($key);
	    clearstatcache();
	    if(!file_exists($ksFile)) return false;
	    $store = unserialize(file_get_contents($ksFile));
	    $mtime = filemtime($ksFile);
	    if(($mtime + $store['ttl']) > time())
			return $store['data'];
	    else
			return false;
    }

    function store($key,$data,$ttl) {
	    $store = array('ttl' => $ttl, 'data' => $data);
	    file_put_contents($this->getkeystore($key), serialize($store));
		return true;
    }

	function getkeystore($key){
	    return $this->getPrefix() . '.' . md5($key);
	}
	
	function getPrefix(){
		return dirname(__FILE__).'/cache/WP_Store-' . md5($_SERVER['HTTP_HOST']);
	}


		function WP_Object_Cache()
		{
			// Empty Constructor
		}
	}

?>