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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_EVENTS_EVENT_TARGETER_H_
#define UI_EVENTS_EVENT_TARGETER_H_
#include "base/memory/weak_ptr.h"
#include "ui/events/events_export.h"
namespace ui {
class Event;
class EventSink;
class EventTarget;
class EVENTS_EXPORT EventTargeter {
public:
EventTargeter();
EventTargeter(const EventTargeter&) = delete;
EventTargeter& operator=(const EventTargeter&) = delete;
virtual ~EventTargeter();
// Returns the target |event| should be dispatched to. If there is no such
// target, return NULL. If |event| is a located event, the location of |event|
// is in the coordinate space of |root|. Furthermore, the targeter can mutate
// the event (e.g., by changing the location of the event to be in the
// returned target's coordinate space) so that it can be dispatched to the
// target without any further modification.
virtual EventTarget* FindTargetForEvent(EventTarget* root, Event* event) = 0;
// Returns the next best target for |event| as compared to |previous_target|.
// |event| is in the local coordinate space of |previous_target|.
// Also mutates |event| so that it can be dispatched to the returned target
// (e.g., by changing |event|'s location to be in the returned target's
// coordinate space).
virtual EventTarget* FindNextBestTarget(EventTarget* previous_target,
Event* event) = 0;
// Returns new event sink if the `in_out_event` should be dispatched to a
// different sink. The event will be updated so that it can be dispatched to
// the new sink correctly. Returns `nullptr` if the event do not have to be
// redirected.
virtual EventSink* GetNewEventSinkForEvent(const EventTarget* current_root,
EventTarget* target,
Event* in_out_event);
private:
friend class EventProcessor;
base::WeakPtr<EventTargeter> GetWeakPtr() {
return weak_ptr_factory_.GetWeakPtr();
}
base::WeakPtrFactory<EventTargeter> weak_ptr_factory_{this};
};
} // namespace ui
#endif // UI_EVENTS_EVENT_TARGETER_H_
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