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nsNativeDragTarget.h
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00001 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
00002 /* ***** BEGIN LICENSE BLOCK *****
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00011  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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00014  *
00015  * The Original Code is Mozilla Communicator client code.
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00017  * The Initial Developer of the Original Code is
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00037 #ifndef _nsNativeDragTarget_h_
00038 #define _nsNativeDragTarget_h_
00039 
00040 #include "nsGUIEvent.h"
00041 #include "nsCOMPtr.h"
00042 #include "nsIDragSession.h"
00043 #include <ole2.h>
00044 
00045 class nsIDragService;
00046 class nsIWidget;
00047 
00048 struct IDataObject;
00049 
00050 /*
00051  * nsNativeDragTarget implements the IDropTarget interface and gets most of its
00052  * behavior from the associated adapter (m_dragDrop).
00053  */
00054 
00055 class nsNativeDragTarget : public IDropTarget
00056 {
00057 public:
00058   nsNativeDragTarget(nsIWidget * aWnd);
00059   ~nsNativeDragTarget();
00060 
00061   // IUnknown members - see iunknown.h for documentation
00062   STDMETHODIMP QueryInterface(REFIID, void**);
00063   STDMETHODIMP_(ULONG) AddRef();
00064   STDMETHODIMP_(ULONG) Release();
00065 
00066   // IDataTarget members
00067 
00068   // Set pEffect based on whether this object can support a drop based on
00069   // the data available from pSource, the key and mouse states specified
00070   // in grfKeyState, and the coordinates specified by point. This is
00071   // called by OLE when a drag enters this object's window (as registered
00072   // by Initialize).
00073   STDMETHODIMP DragEnter(LPDATAOBJECT pSource, DWORD grfKeyState,
00074                          POINTL point, DWORD* pEffect);
00075 
00076   // Similar to DragEnter except it is called frequently while the drag
00077   // is over this object's window.
00078   STDMETHODIMP DragOver(DWORD grfKeyState, POINTL point, DWORD* pEffect);
00079 
00080   // Release the drag-drop source and put internal state back to the point
00081   // before the call to DragEnter. This is called when the drag leaves
00082   // without a drop occurring.
00083   STDMETHODIMP DragLeave();
00084 
00085   // If point is within our region of interest and pSource's data supports
00086   // one of our formats, get the data and set pEffect according to
00087   // grfKeyState (DROPEFFECT_MOVE if the control key was not pressed,
00088   // DROPEFFECT_COPY if the control key was pressed). Otherwise return
00089   // E_FAIL.
00090   STDMETHODIMP Drop(LPDATAOBJECT pSource, DWORD grfKeyState,
00091                     POINTL point, DWORD* pEffect);
00092 
00093 protected:
00094 
00095   void GetGeckoDragAction(LPDATAOBJECT pData, DWORD grfKeyState,
00096                           LPDWORD pdwEffect, PRUint32 * aGeckoAction);
00097   void ProcessDrag(LPDATAOBJECT pData, PRUint32 aEventType, DWORD grfKeyState,
00098                    POINTL pt, DWORD* pdwEffect);
00099   void DispatchDragDropEvent(PRUint32 aType, POINTL pt);
00100 
00101   // Native Stuff
00102   ULONG            m_cRef;      // reference count
00103   HWND             mHWnd;
00104   PRBool           mCanMove;
00105 
00106   // Gecko Stuff
00107   nsIWidget      * mWindow;
00108   nsIDragService * mDragService;
00109 };
00110 
00111 #endif // _nsNativeDragTarget_h_
00112 
00113