ui/platform_window/wm/wm_drop_handler.h

// Copyright 2019 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_PLATFORM_WINDOW_WM_WM_DROP_HANDLER_H_
#define UI_PLATFORM_WINDOW_WM_WM_DROP_HANDLER_H_

#include <memory>

#include "base/component_export.h"

namespace gfx {
class PointF;
}

namespace ui {
class PlatformWindow;
class OSExchangeData;

class COMPONENT_EXPORT(WM) WmDropHandler {
 public:
  // Notifies that drag has entered the window.
  // |point| is in the coordinate space of the PlatformWindow.
  // |operation| contains bitmask of ui::DragDropTypes suggested by the source.
  // |modifiers| contains bitmask of ui::EventFlags that accompany the event.
  virtual void OnDragEnter(const gfx::PointF& point,
                           std::unique_ptr<OSExchangeData> data,
                           int operation,
                           int modifiers) = 0;

  // Notifies that drag location has changed.
  // |point| is in the coordinate space of the PlatformWindow.
  // |operation| contains bitmask of ui::DragDropTypes suggested by the source.
  // |modifiers| contains bitmask of ui::EventFlags that accompany the event.
  // Returns one of ui::DragDropTypes values selected by the client.
  virtual int OnDragMotion(const gfx::PointF& point,
                           int operation,
                           int modifiers) = 0;

  // Notifies that dragged data is dropped. When it doesn't deliver
  // the dragged data on OnDragEnter, it should put it to |data|. The location
  // of the drop is the location of the latest DragEnter/DragMotion. If
  // OSExchangeData is provided on OnDragEnter, the |data| should be same as it.
  // |modifiers| contains bitmask of ui::EventFlags that accompany the event.
  virtual void OnDragDrop(std::unique_ptr<OSExchangeData> data,
                          int modifiers) = 0;

  // Notifies that dragging is left. Must be called before
  // WmDragHandler::OnDragFinished when the drag session gets cancelled.
  virtual void OnDragLeave() = 0;

 protected:
  virtual ~WmDropHandler() = default;
};

COMPONENT_EXPORT(WM)
void SetWmDropHandler(PlatformWindow* platform_window,
                      WmDropHandler* drop_handler);
COMPONENT_EXPORT(WM)
WmDropHandler* GetWmDropHandler(const PlatformWindow& platform_window);

}  // namespace ui

#endif  // UI_PLATFORM_WINDOW_WM_WM_DROP_HANDLER_H_