toolkit/xre/nsUpdateSyncManager.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
   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 nsUpdateSyncManager_h__
   8 #define nsUpdateSyncManager_h__
   9
  10 #include "mozilla/AlreadyAddRefed.h"
  11 #include "nsIObserver.h"
  12 #include "nsIUpdateService.h"
  13 #include "MultiInstanceLock.h"
  14
  15 // The update sync manager is responsible for making sure that only one
  16 // instance of the application is running at the time we want to start updating
  17 // it. It does this by taking a multi-instance lock very early during the
  18 // application's startup process. Then, when app update tasks are ready to run,
  19 // the update service asks us whether anything else has also taken that lock,
  20 // which, if true, would mean another instance of the application is currently
  21 // running and performing update tasks should be avoided (the update service
  22 // also runs a timeout and eventually goes ahead with the update in order to
  23 // prevent an external program from effectively disabling updates).
  24 class nsUpdateSyncManager final : public nsIUpdateSyncManager,
  25                                   public nsIObserver {
  26  public:
  27   explicit nsUpdateSyncManager(nsIFile* anAppFile = nullptr);
  28
  29   NS_DECL_THREADSAFE_ISUPPORTS
  30   NS_DECL_NSIUPDATESYNCMANAGER
  31   NS_DECL_NSIOBSERVER
  32
  33   static already_AddRefed<nsUpdateSyncManager> GetSingleton();
  34
  35  private:
  36   ~nsUpdateSyncManager();
  37
  38   nsUpdateSyncManager(nsUpdateSyncManager&) = delete;
  39   nsUpdateSyncManager(nsUpdateSyncManager&&) = delete;
  40   nsUpdateSyncManager& operator=(nsUpdateSyncManager&) = delete;
  41   nsUpdateSyncManager& operator=(nsUpdateSyncManager&&) = delete;
  42
  43   nsresult OpenLock(nsIFile* anAppFile = nullptr);
  44   void ReleaseLock();
  45
  46   mozilla::MultiInstLockHandle mLock = MULTI_INSTANCE_LOCK_HANDLE_ERROR;
  47 };
  48
  49 #endif  // nsUpdateSyncManager_h__