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/Apc.php

@@ -0,0 +1,64 @@
+<?php defined('SYSPATH') OR die('No direct access allowed.');
+/**
+ * APC-based Cache driver.
+ *
+ * $Id: Apc.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_Apc_Driver implements Cache_Driver {
+
+	public function __construct()
+	{
+		if ( ! extension_loaded('apc'))
+			throw new Kohana_Exception('cache.extension_not_loaded', 'apc');
+	}
+
+	public function get($id)
+	{
+		return (($return = apc_fetch($id)) === FALSE) ? NULL : $return;
+	}
+
+	public function set($id, $data, array $tags = NULL, $lifetime)
+	{
+		if ( ! empty($tags))
+		{
+			Kohana::log('error', 'Cache: tags are unsupported by the APC driver');
+		}
+
+		return apc_store($id, $data, $lifetime);
+	}
+
+	public function find($tag)
+	{
+		Kohana::log('error', 'Cache: tags are unsupported by the APC driver');
+
+		return array();
+	}
+
+	public function delete($id, $tag = FALSE)
+	{
+		if ($tag === TRUE)
+		{
+			Kohana::log('error', 'Cache: tags are unsupported by the APC driver');
+			return FALSE;
+		}
+		elseif ($id === TRUE)
+		{
+			return apc_clear_cache('user');
+		}
+		else
+		{
+			return apc_delete($id);
+		}
+	}
+
+	public function delete_expired()
+	{
+		return TRUE;
+	}
+
+} // End Cache APC Driver