| // Copyright 2015 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef COMPONENTS_KEYED_SERVICE_CORE_KEYED_SERVICE_SHUTDOWN_NOTIFIER_H_ |
| #define COMPONENTS_KEYED_SERVICE_CORE_KEYED_SERVICE_SHUTDOWN_NOTIFIER_H_ |
| |
| #include <memory> |
| |
| #include "base/callback_list.h" |
| #include "base/macros.h" |
| #include "components/keyed_service/core/keyed_service.h" |
| |
| // This is a helper class for objects that depend on one or more keyed services, |
| // but which cannot be keyed services themselves, for example because they don't |
| // correspond 1:1 to a context, or because they have a different lifetime. |
| // |
| // To use this class, add a factory class and declare the dependencies there. |
| // This class (being a KeyedService itself) will be shut down before its |
| // dependencies and notify its observers. |
| class KEYED_SERVICE_EXPORT KeyedServiceShutdownNotifier : public KeyedService { |
| public: |
| using Subscription = base::CallbackList<void()>::Subscription; |
| |
| KeyedServiceShutdownNotifier(); |
| ~KeyedServiceShutdownNotifier() override; |
| |
| // Subscribe for a notification when the keyed services this object depends on |
| // (as defined by its factory) are shut down. The subscription object can be |
| // destroyed to unsubscribe. |
| std::unique_ptr<Subscription> Subscribe(const base::Closure& callback); |
| |
| private: |
| // KeyedService implementation: |
| void Shutdown() override; |
| |
| base::CallbackList<void()> callback_list_; |
| |
| DISALLOW_COPY_AND_ASSIGN(KeyedServiceShutdownNotifier); |
| }; |
| |
| #endif // COMPONENTS_KEYED_SERVICE_CORE_KEYED_SERVICE_SHUTDOWN_NOTIFIER_H_ |