dom/storage/SessionStorageObserver.h

   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::dom {
  13
  14 class SessionStorageObserverChild;
  15
  16 /**
  17  * Effectively just a refcounted life-cycle management wrapper around
  18  * SessionStorageObserverChild which exists to receive chrome observer
  19  * notifications from the main process.
  20  *
  21  * ## Lifecycle ##
  22  * - Created by SessionStorageManager::SessionStorageManager.  Placed in the
  23  *   gSessionStorageObserver variable for subsequent SessionStorageManager's via
  24  *   SessionStorageObserver::Get lookup.
  25  * - The SessionStorageObserverChild directly handles "Observe" messages,
  26  *   shunting them directly to StorageObserver::Notify which distributes them to
  27  *   individual observer sinks.
  28  * - Destroyed when refcount goes to zero due to all owning
  29  *   SessionStorageManager being destroyed.
  30  */
  31 class SessionStorageObserver final {
  32   friend class SessionStorageManager;
  33
  34   SessionStorageObserverChild* mActor;
  35
  36  public:
  37   static SessionStorageObserver* Get();
  38
  39   NS_INLINE_DECL_REFCOUNTING(SessionStorageObserver)
  40
  41   void AssertIsOnOwningThread() const {
  42     NS_ASSERT_OWNINGTHREAD(SessionStorageObserver);
  43   }
  44
  45   void SetActor(SessionStorageObserverChild* aActor);
  46
  47   void ClearActor() {
  48     AssertIsOnOwningThread();
  49     MOZ_ASSERT(mActor);
  50
  51     mActor = nullptr;
  52   }
  53
  54  private:
  55   // Only created by SessionStorageManager.
  56   SessionStorageObserver();
  57
  58   ~SessionStorageObserver();
  59 };
  60
  61 }  // namespace mozilla::dom
  62
  63 #endif  // mozilla_dom_SessionStorageObserver_h