blob: dc37c8ea90731506778e7a3b2f5cade600c4942d [file] [log] [blame]
// Copyright (c) 2011 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.
#include <objidl.h>
#include <wrl/implements.h>
#include "base/component_export.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
namespace ui {
class OSExchangeData;
// A base IDropSource implementation. Handles notifications sent by an active
// drag-drop operation as the user mouses over other drop targets on their
// system. This object tells Windows whether or not the drag should continue,
// and supplies the appropriate cursors.
class DragSourceWin
: public Microsoft::WRL::RuntimeClass<
IDropSource> {
// Factory method to avoid exporting the class and all it derives from.
UI_BASE) Microsoft::WRL::ComPtr<DragSourceWin> Create();
// Use Create() to construct these objects. Direct calls to the constructor
// are an error - it is only public because a WRL helper function creates the
// objects.
~DragSourceWin() override = default;
// Stop the drag operation at the next chance we get. This doesn't
// synchronously stop the drag (since Windows is controlling that),
// but lets us tell Windows to cancel the drag the next chance we get.
void CancelDrag() {
cancel_drag_ = true;
// This is used to tell if the drag drop actually started, for generating
// a BooleanSuccess histogram.
int num_query_continues() const { return num_query_continues_; }
// IDropSource implementation:
HRESULT __stdcall QueryContinueDrag(BOOL escape_pressed,
DWORD key_state) override;
HRESULT __stdcall GiveFeedback(DWORD effect) override;
// Used to set the active data object for the current drag operation. The
// caller must ensure that |data| is not destroyed before the nested drag loop
// terminates.
void set_data(const OSExchangeData* data) { data_ = data; }
virtual void OnDragSourceCancel() {}
virtual void OnDragSourceDrop();
virtual void OnDragSourceMove() {}
// Set to true if we want to cancel the drag operation.
bool cancel_drag_;
const OSExchangeData* data_;
// The number of times for this drag that Windows asked if the drag should
// continue. This is used in DesktopDragDropClientWin::StartDragAndDrop to
// detect if touch drag drop started successfully. See comment there for much
// more info.
int num_query_continues_ = 0;
} // namespace ui