gecko-dev/dom/storage/StorageNotifierService.h

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_dom_StorageNotifierService_h
#define mozilla_dom_StorageNotifierService_h

class nsPIDOMWindowInner;

namespace mozilla {
namespace dom {

class StorageEvent;

/**
 * Enables the StorageNotifierService to check whether an observer is interested
 * in receiving events for the given principal before calling the method, an
 * optimization refactoring.
 *
 * Expected to only be implemented by nsGlobalWindowObserver or its succesor.
 */
class StorageNotificationObserver {
 public:
  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING

  virtual void ObserveStorageNotification(StorageEvent* aEvent,
                                          const char16_t* aStorageType,
                                          bool aPrivateBrowsing) = 0;

  virtual bool IsPrivateBrowsing() const = 0;

  virtual nsIPrincipal* GetEffectiveStoragePrincipal() const = 0;

  virtual nsIEventTarget* GetEventTarget() const = 0;
};

/**
 * A specialized version of the observer service that uses the custom
 * StorageNotificationObserver so that principal checks can happen in this class
 * rather than in the nsIObserver::observe method where they used to happen.
 *
 * The only expected consumers are nsGlobalWindowInner instances via their
 * nsGlobalWindowObserver helper that avoids being able to use the window as an
 * nsIObserver.
 */
class StorageNotifierService final {
 public:
  NS_INLINE_DECL_REFCOUNTING(StorageNotifierService)

  static StorageNotifierService* GetOrCreate();

  static void Broadcast(StorageEvent* aEvent, const char16_t* aStorageType,
                        bool aPrivateBrowsing, bool aImmediateDispatch);

  void Register(StorageNotificationObserver* aObserver);

  void Unregister(StorageNotificationObserver* aObserver);

 private:
  StorageNotifierService();
  ~StorageNotifierService();

  nsTObserverArray<RefPtr<StorageNotificationObserver>> mObservers;
};

}  // namespace dom
}  // namespace mozilla

#endif  // mozilla_dom_StorageNotifierService_h