1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef UI_BASE_DRAGDROP_DRAG_SOURCE_WIN_H_ 6 #define UI_BASE_DRAGDROP_DRAG_SOURCE_WIN_H_ 7 8 #include <objidl.h> 9 10 #include "base/basictypes.h" 11 #include "base/memory/ref_counted.h" 12 #include "ui/base/ui_base_export.h" 13 14 namespace ui { 15 16 // A base IDropSource implementation. Handles notifications sent by an active 17 // drag-drop operation as the user mouses over other drop targets on their 18 // system. This object tells Windows whether or not the drag should continue, 19 // and supplies the appropriate cursors. 20 class UI_BASE_EXPORT DragSourceWin 21 : public IDropSource, 22 public base::RefCountedThreadSafe<DragSourceWin> { 23 public: 24 DragSourceWin(); ~DragSourceWin()25 virtual ~DragSourceWin() {} 26 27 // Stop the drag operation at the next chance we get. This doesn't 28 // synchronously stop the drag (since Windows is controlling that), 29 // but lets us tell Windows to cancel the drag the next chance we get. CancelDrag()30 void CancelDrag() { 31 cancel_drag_ = true; 32 } 33 34 // IDropSource implementation: 35 HRESULT __stdcall QueryContinueDrag(BOOL escape_pressed, DWORD key_state); 36 HRESULT __stdcall GiveFeedback(DWORD effect); 37 38 // IUnknown implementation: 39 HRESULT __stdcall QueryInterface(const IID& iid, void** object); 40 ULONG __stdcall AddRef(); 41 ULONG __stdcall Release(); 42 43 protected: OnDragSourceCancel()44 virtual void OnDragSourceCancel() {} OnDragSourceDrop()45 virtual void OnDragSourceDrop() {} OnDragSourceMove()46 virtual void OnDragSourceMove() {} 47 48 private: 49 // Set to true if we want to cancel the drag operation. 50 bool cancel_drag_; 51 52 DISALLOW_COPY_AND_ASSIGN(DragSourceWin); 53 }; 54 55 } // namespace ui 56 57 #endif // UI_BASE_DRAGDROP_DRAG_SOURCE_WIN_H_ 58