restructured session driver interfaces and added cookie session driver.

system/session/cookie.php

@@ -0,0 +1,54 @@
+<?php namespace System\Session;
+
+use System\Crypt;
+use System\Config;
+
+class Cookie implements Driver {
+
+	public function __construct()
+	{
+		if (Config::get('application.key') == '')
+		{
+			throw new \Exception("You must set an application key before using the Cookie session driver.");
+		}
+	}
+
+	/**
+	 * Load a session by ID.
+	 *
+	 * @param  string  $id
+	 * @return array
+	 */
+	public function load($id)
+	{
+		if (\System\Cookie::has('session_payload'))
+		{
+			return unserialize(Crypt::decrypt(\System\Cookie::get('session_payload')));
+		}
+	}
+
+	/**
+	 * Save a session.
+	 *
+	 * @param  array  $session
+	 * @return void
+	 */
+	public function save($session)
+	{
+		$c = \System\Config::get('session');
+
+		\System\Cookie::put('session_payload', Crypt::encrypt(serialize($session)), $c['lifetime'], $c['path'], $c['domain'], $c['https'], $c['http_only']);
+	}
+
+	/**
+	 * Delete a session by ID.
+	 *
+	 * @param  string  $id
+	 * @return void
+	 */
+	public function delete($id)
+	{
+		\System\Cookie::forget('session_payload');
+	}
+
+}