image/src/ShutdownTracker.h
author Glenn Randers-Pehrson <glennrp+bmo@gmail.com>
Tue, 31 Mar 2015 10:57:00 -0700
changeset 238046 4c13220915e1ec96fc3ed1444ff77a8f45fd0764
parent 206759 f7e8bda1300c0a6a2bf849e56e736023701d7ff7
child 243824 2ef80cf97822b7b4e475da1536b282971029c97a
permissions -rw-r--r--
Bug 1102048 (Part 38, ShutdownTracker) - Make image/src files comply with the Mozilla Coding Style Guide. r=seth

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */

/**
 * ShutdownTracker is an imagelib-global service that allows callers to check
 * whether shutdown has started.
 */

#ifndef mozilla_image_src_ShutdownTracker_h
#define mozilla_image_src_ShutdownTracker_h

namespace mozilla {
namespace image {

/**
 * ShutdownTracker is an imagelib-global service that allows callers to check
 * whether shutdown has started. It exists to avoid the need for registering
 * many 'xpcom-shutdown' notification observers on short-lived objects, which
 * would have an unnecessary performance cost.
 */
struct ShutdownTracker
{
  /**
   * Initialize static data. Called during imagelib module initialization.
   */
  static void Initialize();

  /**
   * Check whether shutdown has started. Callers can use this to check whether
   * it's safe to access XPCOM services; if shutdown has started, such calls
   * must be avoided.
   *
   * @return true if shutdown has already started.
   */
  static bool ShutdownHasStarted();

private:
  virtual ~ShutdownTracker() = 0;  // Forbid instantiation.
};

} // namespace image
} // namespace mozilla

#endif // mozilla_image_src_ShutdownTracker_h