1: <?php namespace Laravel\Session\Drivers; use Laravel\Config, Laravel\Str;
 2: 
 3: abstract class Driver {
 4: 
 5:     /**
 6:      * Load a session from storage by a given ID.
 7:      *
 8:      * If no session is found for the ID, null will be returned.
 9:      *
10:      * @param  string  $id
11:      * @return array
12:      */
13:     abstract public function load($id);
14: 
15:     /**
16:      * Save a given session to storage.
17:      *
18:      * @param  array  $session
19:      * @param  array  $config
20:      * @param  bool   $exists
21:      * @return void
22:      */
23:     abstract public function save($session, $config, $exists);
24: 
25:     /**
26:      * Delete a session from storage by a given ID.
27:      *
28:      * @param  string  $id
29:      * @return void
30:      */
31:     abstract public function delete($id);
32: 
33:     /**
34:      * Create a fresh session array with a unique ID.
35:      *
36:      * @return array
37:      */
38:     public function fresh()
39:     {
40:         // We will simply generate an empty session payload array, using an ID
41:         // that is not currently assigned to any existing session within the
42:         // application and return it to the driver.
43:         return array('id' => $this->id(), 'data' => array(
44:             ':new:' => array(),
45:             ':old:' => array(),
46:         ));
47:     }
48: 
49:     /**
50:      * Get a new session ID that isn't assigned to any current session.
51:      *
52:      * @return string
53:      */
54:     public function id()
55:     {
56:         $session = array();
57: 
58:         // If the driver is an instance of the Cookie driver, we are able to
59:         // just return any string since the Cookie driver has no real idea
60:         // of a server side persisted session with an ID.
61:         if ($this instanceof Cookie)
62:         {
63:             return Str::random(40);
64:         }
65: 
66:         // We'll continue generating random IDs until we find an ID that is
67:         // not currently assigned to a session. This is almost definitely
68:         // going to happen on the first iteration.
69:         do {
70: 
71:             $session = $this->load($id = Str::random(40));          
72: 
73:         } while ( ! is_null($session));
74: 
75:         return $id;
76:     }
77: 
78: }