| // Copyright 2014 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 UI_EVENTS_PLATFORM_SCOPED_EVENT_DISPATCHER_H_ |
| #define UI_EVENTS_PLATFORM_SCOPED_EVENT_DISPATCHER_H_ |
| |
| #include "base/auto_reset.h" |
| #include "base/basictypes.h" |
| #include "ui/events/events_export.h" |
| |
| namespace ui { |
| |
| class PlatformEventDispatcher; |
| |
| // A temporary PlatformEventDispatcher can be installed on a |
| // PlatformEventSource that overrides all installed event dispatchers, and |
| // always gets a chance to dispatch the event first. The PlatformEventSource |
| // returns a ScopedEventDispatcher object in such cases. This |
| // ScopedEventDispatcher object can be used to dispatch the event to any |
| // previous overridden dispatcher. When this object is destroyed, it removes the |
| // override-dispatcher, and restores the previous override-dispatcher. |
| class EVENTS_EXPORT ScopedEventDispatcher { |
| public: |
| ScopedEventDispatcher(PlatformEventDispatcher** scoped_dispatcher, |
| PlatformEventDispatcher* new_dispatcher); |
| ~ScopedEventDispatcher(); |
| |
| operator PlatformEventDispatcher*() const { return original_; } |
| |
| private: |
| PlatformEventDispatcher* original_; |
| base::AutoReset<PlatformEventDispatcher*> restore_; |
| |
| DISALLOW_COPY_AND_ASSIGN(ScopedEventDispatcher); |
| }; |
| |
| } // namespace ui |
| |
| #endif // UI_EVENTS_PLATFORM_SCOPED_EVENT_DISPATCHER_H_ |