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// Copyright (c) 2010 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 BASE_BASE_DRAG_SOURCE_H_
#define BASE_BASE_DRAG_SOURCE_H_
#include <objidl.h>
#include "base/basictypes.h"
#include "base/ref_counted.h"
///////////////////////////////////////////////////////////////////////////////
//
// BaseDragSource
//
// 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 BaseDragSource : public IDropSource,
public base::RefCountedThreadSafe<BaseDragSource> {
public:
BaseDragSource();
virtual ~BaseDragSource() { }
// 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;
}
// IDropSource implementation:
HRESULT __stdcall QueryContinueDrag(BOOL escape_pressed, DWORD key_state);
HRESULT __stdcall GiveFeedback(DWORD effect);
// IUnknown implementation:
HRESULT __stdcall QueryInterface(const IID& iid, void** object);
ULONG __stdcall AddRef();
ULONG __stdcall Release();
protected:
virtual void OnDragSourceCancel() { }
virtual void OnDragSourceDrop() { }
virtual void OnDragSourceMove() { }
private:
// Set to true if we want to cancel the drag operation.
bool cancel_drag_;
DISALLOW_COPY_AND_ASSIGN(BaseDragSource);
};
#endif // BASE_BASE_DRAG_SOURCE_H_
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