Rename 'kohana' to 'system' to conform to the Kohana filesystem layout. I'm comfortable with us not clearly drawing the distinction about the fact that it's Kohana.

system/libraries/drivers/Cache/Xcache.php

@@ -0,0 +1,119 @@
+<?php defined('SYSPATH') OR die('No direct access allowed.');
+/**
+ * Xcache Cache driver.
+ *
+ * $Id: Xcache.php 4046 2009-03-05 19:23:29Z Shadowhand $
+ *
+ * @package    Cache
+ * @author     Kohana Team
+ * @copyright  (c) 2007-2008 Kohana Team
+ * @license    http://kohanaphp.com/license.html
+ */
+class Cache_Xcache_Driver implements Cache_Driver {
+
+	public function __construct()
+	{
+		if ( ! extension_loaded('xcache'))
+			throw new Kohana_Exception('cache.extension_not_loaded', 'xcache');
+	}
+
+	public function get($id)
+	{
+		if (xcache_isset($id))
+			return xcache_get($id);
+
+		return NULL;
+	}
+
+	public function set($id, $data, array $tags = NULL, $lifetime)
+	{
+		if ( ! empty($tags))
+		{
+			Kohana::log('error', 'Cache: tags are unsupported by the Xcache driver');
+		}
+
+		return xcache_set($id, $data, $lifetime);
+	}
+
+	public function find($tag)
+	{
+		Kohana::log('error', 'Cache: tags are unsupported by the Xcache driver');
+		return FALSE;
+	}
+
+	public function delete($id, $tag = FALSE)
+	{
+		if ($tag !== FALSE)
+		{
+			Kohana::log('error', 'Cache: tags are unsupported by the Xcache driver');
+			return TRUE;
+		}
+		elseif ($id !== TRUE)
+		{
+			if (xcache_isset($id))
+				return xcache_unset($id);
+
+			return FALSE;
+		}
+		else
+		{
+			// Do the login
+			$this->auth();
+			$result = TRUE;
+			for ($i = 0, $max = xcache_count(XC_TYPE_VAR); $i < $max; $i++)
+			{
+				if (xcache_clear_cache(XC_TYPE_VAR, $i) !== NULL)
+				{
+					$result = FALSE;
+					break;
+				}
+			}
+
+			// Undo the login
+			$this->auth(TRUE);
+			return $result;
+		}
+
+		return TRUE;
+	}
+
+	public function delete_expired()
+	{
+		return TRUE;
+	}
+
+	private function auth($reverse = FALSE)
+	{
+		static $backup = array();
+
+		$keys = array('PHP_AUTH_USER', 'PHP_AUTH_PW');
+
+		foreach ($keys as $key)
+		{
+			if ($reverse)
+			{
+				if (isset($backup[$key]))
+				{
+					$_SERVER[$key] = $backup[$key];
+					unset($backup[$key]);
+				}
+				else
+				{
+					unset($_SERVER[$key]);
+				}
+			}
+			else
+			{
+				$value = getenv($key);
+
+				if ( ! empty($value))
+				{
+					$backup[$key] = $value;
+				}
+
+				$_SERVER[$key] = Kohana::config('cache_xcache.'.$key);
+			}
+		}
+	}
+
+} // End Cache Xcache Driver