tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
Log | Files | Refs | README | LICENSE

LSObserver.h (2133B)

      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_localstorage_LSObserver_h
      8 #define mozilla_dom_localstorage_LSObserver_h
      9 
     10 #include "mozilla/Assertions.h"
     11 #include "nsISupports.h"
     12 #include "nsString.h"
     13 
     14 namespace mozilla::dom {
     15 
     16 class LSObserverChild;
     17 
     18 /**
     19 * Effectively just a refcounted life-cycle management wrapper around
     20 * LSObserverChild which exists to receive "storage" event information from
     21 * other processes.  (Same-process events are handled within the process, see
     22 * `LSObject::OnChange`.)
     23 *
     24 * ## Lifecycle ##
     25 * - Created by LSObject::EnsureObserver via synchronous LSRequest idiom
     26 *   whenever the first window's origin adds a "storage" event.  Placed in the
     27 *   gLSObservers LSObserverHashtable for subsequent LSObject's via
     28 *   LSObserver::Get lookup.
     29 * - The LSObserverChild directly handles "Observe" messages, shunting them
     30 *   directly to Storage::NotifyChange which does all the legwork of notifying
     31 *   windows about "storage" events.
     32 * - Destroyed when refcount goes to zero due to all owning LSObjects being
     33 *   destroyed or having their `LSObject::DropObserver` methods invoked due to
     34 *   the last "storage" event listener being removed from the owning window.
     35 */
     36 class LSObserver final {
     37  friend class LSObject;
     38 
     39  LSObserverChild* mActor;
     40 
     41  const nsCString mOrigin;
     42 
     43 public:
     44  static LSObserver* Get(const nsACString& aOrigin);
     45 
     46  NS_INLINE_DECL_REFCOUNTING(LSObserver)
     47 
     48  void AssertIsOnOwningThread() const { NS_ASSERT_OWNINGTHREAD(LSObserver); }
     49 
     50  void SetActor(LSObserverChild* aActor);
     51 
     52  void ClearActor() {
     53    AssertIsOnOwningThread();
     54    MOZ_ASSERT(mActor);
     55 
     56    mActor = nullptr;
     57  }
     58 
     59 private:
     60  // Only created by LSObject.
     61  explicit LSObserver(const nsACString& aOrigin);
     62 
     63  ~LSObserver();
     64 };
     65 
     66 }  // namespace mozilla::dom
     67 
     68 #endif  // mozilla_dom_localstorage_LSObserver_h