tweaked cache and session namespacing.

system/session/file.php

@@ -0,0 +1,58 @@
+<?php namespace System\Session;
+
+class File implements Driver {
+
+	/**
+	 * Load a session by ID.
+	 *
+	 * @param  string  $id
+	 * @return array
+	 */
+	public function load($id)
+	{
+		if (file_exists($path = SESSION_PATH.$id))
+		{
+			return unserialize(file_get_contents($path));
+		}
+	}
+
+	/**
+	 * Save a session.
+	 *
+	 * @param  array  $session
+	 * @return void
+	 */
+	public function save($session)
+	{
+		file_put_contents(SESSION_PATH.$session['id'], serialize($session), LOCK_EX);
+	}
+
+	/**
+	 * Delete a session by ID.
+	 *
+	 * @param  string  $id
+	 * @return void
+	 */
+	public function delete($id)
+	{
+		@unlink(SESSION_PATH.$id);
+	}
+
+	/**
+	 * Delete all expired sessions.
+	 *
+	 * @param  int   $expiration
+	 * @return void
+	 */
+	public function sweep($expiration)
+	{
+		foreach (glob(SESSION_PATH.'*') as $file)
+		{
+			if (filetype($file) == 'file' and filemtime($file) < $expiration)
+			{
+				@unlink($file);
+			}			
+		}
+	}
+	
+}