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// Copyright 2015 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_SCOPED_TARGET_HANDLER_H_
#define UI_EVENTS_SCOPED_TARGET_HANDLER_H_
#include <string_view>
#include "base/memory/raw_ptr.h"
#include "base/memory/weak_ptr.h"
#include "ui/events/event_handler.h"
#include "ui/events/events_export.h"
namespace ui {
class EventTarget;
// An EventHandler that replaces an EventTarget's target handler with itself to
// pass events first to the original handler and second to an additional new
// EventHandler. The new handler gets called after the original handler even
// if it calls SetHandled() on the event but not if StopPropagation() is called
// on the event.
class EVENTS_EXPORT ScopedTargetHandler : public EventHandler {
public:
ScopedTargetHandler(EventTarget* target, EventHandler* new_handler);
ScopedTargetHandler(const ScopedTargetHandler&) = delete;
ScopedTargetHandler& operator=(const ScopedTargetHandler&) = delete;
~ScopedTargetHandler() override;
// EventHandler:
void OnEvent(Event* event) override;
std::string_view GetLogContext() const override;
private:
// An EventTarget that has its target handler replaced with |this| for a life
// time of |this|.
raw_ptr<EventTarget> target_;
// An EventHandler that gets restored on |view_| when |this| is destroyed.
raw_ptr<EventHandler> original_handler_;
// A new handler that gets events in addition to the |original_handler_|.
raw_ptr<EventHandler> new_handler_;
// Used to detect if handling an event has caused |this| to be deleted. Must
// be last.
base::WeakPtrFactory<ScopedTargetHandler> weak_factory_{this};
};
} // namespace ui
#endif // UI_EVENTS_SCOPED_TARGET_HANDLER_H_
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