ShutdownTracker.h (1407B)
1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ 2 /* This Source Code Form is subject to the terms of the Mozilla Public 3 * License, v. 2.0. If a copy of the MPL was not distributed with this 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 5 6 /** 7 * ShutdownTracker is an imagelib-global service that allows callers to check 8 * whether shutdown has started. 9 */ 10 11 #ifndef mozilla_image_ShutdownTracker_h 12 #define mozilla_image_ShutdownTracker_h 13 14 namespace mozilla { 15 namespace image { 16 17 /** 18 * ShutdownTracker is an imagelib-global service that allows callers to check 19 * whether shutdown has started. It exists to avoid the need for registering 20 * many 'xpcom-will-shutdown' notification observers on short-lived objects, 21 * which would have an unnecessary performance cost. 22 */ 23 struct ShutdownTracker { 24 /** 25 * Initialize static data. Called during imagelib module initialization. 26 */ 27 static void Initialize(); 28 29 /** 30 * Check whether shutdown has started. Callers can use this to check whether 31 * it's safe to access XPCOM services; if shutdown has started, such calls 32 * must be avoided. 33 * 34 * @return true if shutdown has already started. 35 */ 36 static bool ShutdownHasStarted(); 37 38 private: 39 virtual ~ShutdownTracker() = 0; // Forbid instantiation. 40 }; 41 42 } // namespace image 43 } // namespace mozilla 44 45 #endif // mozilla_image_ShutdownTracker_h