1// Copyright 2014 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#ifndef UI_EVENTS_PLATFORM_PLATFORM_EVENT_DISPATCHER_H_ 6#define UI_EVENTS_PLATFORM_PLATFORM_EVENT_DISPATCHER_H_ 7 8#include "base/basictypes.h" 9#include "ui/events/events_export.h" 10#include "ui/events/platform/platform_event_types.h" 11 12namespace ui { 13 14// See documentation for |PlatformEventDispatcher::DispatchEvent()| for 15// explanation of the meaning of the flags. 16enum PostDispatchAction { 17 POST_DISPATCH_NONE = 0x0, 18 POST_DISPATCH_PERFORM_DEFAULT = 0x1, 19 POST_DISPATCH_STOP_PROPAGATION = 0x2, 20}; 21 22// PlatformEventDispatcher receives events from a PlatformEventSource and 23// dispatches them. 24class EVENTS_EXPORT PlatformEventDispatcher { 25 public: 26 // Returns whether this dispatcher wants to dispatch |event|. 27 virtual bool CanDispatchEvent(const PlatformEvent& event) = 0; 28 29 // Dispatches |event|. If this is not the default dispatcher, then the 30 // dispatcher can request that the default dispatcher gets a chance to 31 // dispatch the event by setting POST_DISPATCH_PERFORM_DEFAULT to the return 32 // value. If the dispatcher has processed the event, and no other dispatcher 33 // should be allowed to dispatch the event, then the dispatcher should set 34 // POST_DISPATCH_STOP_PROPAGATION flag on the return value. 35 virtual uint32_t DispatchEvent(const PlatformEvent& event) = 0; 36 37 protected: 38 virtual ~PlatformEventDispatcher() {} 39}; 40 41} // namespace ui 42 43#endif // UI_EVENTS_PLATFORM_PLATFORM_EVENT_DISPATCHER_H_ 44