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ash / drag_drop / scoped_drag_drop_observer.h [blame]
// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef ASH_DRAG_DROP_SCOPED_DRAG_DROP_OBSERVER_H_
#define ASH_DRAG_DROP_SCOPED_DRAG_DROP_OBSERVER_H_
#include "ash/shell_observer.h"
#include "base/functional/callback.h"
#include "base/scoped_observation.h"
#include "ui/aura/client/drag_drop_client_observer.h"
namespace ui {
class DropTargetEvent;
} // namespace ui
namespace aura::client {
class DragDropClient;
} // namespace aura::client
namespace ash {
class Shell;
// A class which observes an `aura::client::DragDropClient` for the scope of its
// existence. Drag events are passed to a callback supplied in the constructor.
class ASH_EXPORT ScopedDragDropObserver
: public aura::client::DragDropClientObserver,
public ShellObserver {
public:
enum class EventType { kDragUpdated, kDragCompleted, kDragCancelled };
// NOTE: `event` is `nullptr` for `event_type` == `EventType::kDragCancelled`.
using EventCallback =
base::RepeatingCallback<void(EventType event_type,
const ui::DropTargetEvent* event)>;
ScopedDragDropObserver(aura::client::DragDropClient* client,
EventCallback event_callback);
ScopedDragDropObserver(const ScopedDragDropObserver&) = delete;
ScopedDragDropObserver& operator=(const ScopedDragDropObserver&) = delete;
~ScopedDragDropObserver() override;
private:
// aura::client::DragDropClientObserver:
void OnDragUpdated(const ui::DropTargetEvent& event) override;
void OnDragCompleted(const ui::DropTargetEvent& event) override;
void OnDragCancelled() override;
// ShellObserver:
void OnShellDestroying() override;
EventCallback event_callback_;
base::ScopedObservation<aura::client::DragDropClient,
aura::client::DragDropClientObserver>
drag_drop_client_observer_{this};
base::ScopedObservation<Shell, ShellObserver> shell_observer_{this};
};
} // namespace ash
#endif // ASH_DRAG_DROP_SCOPED_DRAG_DROP_OBSERVER_H_