1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4  * License, v. 2.0. If a copy of the MPL was not distributed with this
5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6 
7 #ifndef mozilla_dom_SessionStorageObserver_h
8 #define mozilla_dom_SessionStorageObserver_h
9 
10 #include "nsISupportsImpl.h"
11 
12 namespace mozilla {
13 namespace dom {
14 
15 class SessionStorageObserverChild;
16 
17 /**
18  * Effectively just a refcounted life-cycle management wrapper around
19  * SessionStorageObserverChild which exists to receive chrome observer
20  * notifications from the main process.
21  *
22  * ## Lifecycle ##
23  * - Created by SessionStorageManager::SessionStorageManager.  Placed in the
24  *   gSessionStorageObserver variable for subsequent SessionStorageManager's via
25  *   SessionStorageObserver::Get lookup.
26  * - The SessionStorageObserverChild directly handles "Observe" messages,
27  *   shunting them directly to StorageObserver::Notify which distributes them to
28  *   individual observer sinks.
29  * - Destroyed when refcount goes to zero due to all owning
30  *   SessionStorageManager being destroyed.
31  */
32 class SessionStorageObserver final {
33   friend class SessionStorageManager;
34 
35   SessionStorageObserverChild* mActor;
36 
37  public:
38   static SessionStorageObserver* Get();
39 
NS_INLINE_DECL_REFCOUNTING(SessionStorageObserver)40   NS_INLINE_DECL_REFCOUNTING(SessionStorageObserver)
41 
42   void AssertIsOnOwningThread() const {
43     NS_ASSERT_OWNINGTHREAD(SessionStorageObserver);
44   }
45 
46   void SetActor(SessionStorageObserverChild* aActor);
47 
ClearActor()48   void ClearActor() {
49     AssertIsOnOwningThread();
50     MOZ_ASSERT(mActor);
51 
52     mActor = nullptr;
53   }
54 
55  private:
56   // Only created by SessionStorageManager.
57   SessionStorageObserver();
58 
59   ~SessionStorageObserver();
60 };
61 
62 }  // namespace dom
63 }  // namespace mozilla
64 
65 #endif  // mozilla_dom_SessionStorageObserver_h
66