ole/clipboard.c

/*
 *  OLE 2 clipboard support
 *
 *      Copyright 1999  Noel Borthwick <noel@macadamian.com>
 *
 * NOTES:
 *    This file contains the implementation for the OLE Clipboard and its
 *    internal interfaces. The OLE clipboard interacts with an IDataObject
 *    interface via the OleSetClipboard, OleGetClipboard and
 *    OleIsCurrentClipboard API's. An internal IDataObject delegates
 *    to a client supplied IDataObject or the WIN32 clipboard API depending
 *    on whether OleSetClipboard has been invoked.
 *    Here are some operating scenarios:
 *
 *    1. OleSetClipboard called: In this case the internal IDataObject
 *       delegates to the client supplied IDataObject. Additionally OLE takes
 *       ownership of the Windows clipboard and any HGLOCBAL IDataObject
 *       items are placed on the Windows clipboard. This allows non OLE aware
 *       applications to access these. A local WinProc fields WM_RENDERFORMAT
 *       and WM_RENDERALLFORMATS messages in this case.
 *
 *    2. OleGetClipboard called without previous OleSetClipboard. Here the internal
 *       IDataObject functionality wraps around the WIN32 clipboard API.
 *
 *    3. OleGetClipboard called after previous OleSetClipboard. Here the internal
 *       IDataObject delegates to the source IDataObjects functionality directly,
 *       thereby bypassing the Windows clipboard.
 *
 *    Implementation references : Inside OLE 2'nd  edition by Kraig Brockschmidt
 *
 * TODO:
 *    - Support for pasting between different processes. OLE clipboard support
 *      currently works only for in process copy and paste. Since we internally
 *      store a pointer to the source's IDataObject and delegate to that, this
 *      will fail if the IDataObject client belongs to a different process.
 *    - IDataObject::GetDataHere is not implemented
 *    - OleFlushClipboard needs to additionally handle TYMED_IStorage media
 *      by copying the storage into global memory. Subsequently the default
 *      data object exposed through OleGetClipboard must convert this TYMED_HGLOBAL
 *      back to TYMED_IStorage.
 *    - OLE1 compatibility formats to be synthesized from OLE2 formats and put on
 *      clipboard in OleSetClipboard.
 *
 */

#include <assert.h>
#include "winuser.h"
#include "winerror.h"
#include "ole2.h"
#include "class.h"
#include "debugtools.h"


#define HANDLE_ERROR(err) { hr = err; TRACE("(HRESULT=%lx)\n", (HRESULT)err); goto CLEANUP; }

/* For CoGetMalloc (MEMCTX_TASK is currently ignored) */
#ifndef MEMCTX_TASK
  #define MEMCTX_TASK -1
#endif

DEFAULT_DEBUG_CHANNEL(ole)

/****************************************************************************
 * OLEClipbrd
 * DO NOT add any members before the VTables declaration!
 */
struct OLEClipbrd
{
  /*
   * List all interface VTables here
   */
  ICOM_VTABLE(IDataObject)*  lpvtbl1;  /* IDataObject VTable */

  /*
   * The hidden OLE clipboard window. This window is used as the bridge between the 
   * the OLE and windows clipboard API. (Windows creates one such window per process)
   */
  HWND                       hWndClipboard;

  /*
   * Pointer to the source data object (via OleSetClipboard)
   */
  IDataObject*               pIDataObjectSrc;

  /*
   * The registered DataObject clipboard format
   */
  UINT                       cfDataObj;

  /*
   * The handle to our ourself
   */
  UINT                       hSelf;

  /*
   * Reference count of this object
   */
  ULONG                      ref;
};

typedef struct OLEClipbrd OLEClipbrd;


/****************************************************************************
*   IEnumFORMATETC implementation
*   DO NOT add any members before the VTables declaration!
*/
typedef struct 
{
  /* IEnumFORMATETC VTable */
  ICOM_VTABLE(IEnumFORMATETC)* lpvtbl;
  
  /* IEnumFORMATETC fields */
  UINT                         posFmt;    /* current enumerator position */
  UINT                         countFmt;  /* number of EnumFORMATETC's in array */
  LPFORMATETC                  pFmt;      /* array of EnumFORMATETC's */

  /*
   * Reference count of this object
   */
  DWORD                        ref;

  /*
   * IUnknown implementation of the parent data object.
   */
  IUnknown*                    pUnkDataObj;
  
} IEnumFORMATETCImpl;


/*
 * The one and only OLEClipbrd object which is created by OLEClipbrd_Initialize()
 */
static HGLOBAL hTheOleClipboard = 0;
static OLEClipbrd* theOleClipboard = NULL;


/*
 * Prototypes for the methods of the OLEClipboard class.
 */
extern void OLEClipbrd_Initialize();
extern void OLEClipbrd_UnInitialize();
static OLEClipbrd* OLEClipbrd_Construct();
static void OLEClipbrd_Destroy(OLEClipbrd* ptrToDestroy);
static HWND OLEClipbrd_CreateWindow();
static void OLEClipbrd_DestroyWindow(HWND hwnd);
LRESULT CALLBACK OLEClipbrd_WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);
static HRESULT OLEClipbrd_RenderFormat(LPFORMATETC pFormatetc);
static HGLOBAL OLEClipbrd_GlobalDupMem( HGLOBAL hGlobalSrc );

/*
 * Prototypes for the methods of the OLEClipboard class
 * that implement IDataObject methods.
 */
static HRESULT WINAPI OLEClipbrd_IDataObject_QueryInterface(
            IDataObject*     iface,
            REFIID           riid,
            void**           ppvObject);
static ULONG WINAPI OLEClipbrd_IDataObject_AddRef( 
            IDataObject*     iface);
static ULONG WINAPI OLEClipbrd_IDataObject_Release( 
            IDataObject*     iface);
static HRESULT WINAPI OLEClipbrd_IDataObject_GetData(
	    IDataObject*     iface,
	    LPFORMATETC      pformatetcIn, 
	    STGMEDIUM*       pmedium);
static HRESULT WINAPI OLEClipbrd_IDataObject_GetDataHere(
	    IDataObject*     iface, 
	    LPFORMATETC      pformatetc,
	    STGMEDIUM*       pmedium);
static HRESULT WINAPI OLEClipbrd_IDataObject_QueryGetData(
	    IDataObject*     iface,
	    LPFORMATETC      pformatetc);
static HRESULT WINAPI OLEClipbrd_IDataObject_GetCanonicalFormatEtc(
	    IDataObject*     iface, 
	    LPFORMATETC      pformatectIn, 
	    LPFORMATETC      pformatetcOut);
static HRESULT WINAPI OLEClipbrd_IDataObject_SetData(
	    IDataObject*     iface,
	    LPFORMATETC      pformatetc, 
	    STGMEDIUM*       pmedium, 
	    BOOL             fRelease);
static HRESULT WINAPI OLEClipbrd_IDataObject_EnumFormatEtc(
	    IDataObject*     iface,       
	    DWORD            dwDirection,
	    IEnumFORMATETC** ppenumFormatEtc);
static HRESULT WINAPI OLEClipbrd_IDataObject_DAdvise(
	    IDataObject*     iface, 
	    FORMATETC*       pformatetc, 
	    DWORD            advf, 
	    IAdviseSink*     pAdvSink, 
	    DWORD*           pdwConnection);
static HRESULT WINAPI OLEClipbrd_IDataObject_DUnadvise(
	    IDataObject*     iface,
	    DWORD            dwConnection);
static HRESULT WINAPI OLEClipbrd_IDataObject_EnumDAdvise(
	    IDataObject*     iface,
	    IEnumSTATDATA**  ppenumAdvise);

/*
 * Prototypes for the IEnumFORMATETC methods.
 */
static LPENUMFORMATETC OLEClipbrd_IEnumFORMATETC_Construct(UINT cfmt, const FORMATETC afmt[],
                                                           LPUNKNOWN pUnkDataObj);
static HRESULT WINAPI OLEClipbrd_IEnumFORMATETC_QueryInterface(LPENUMFORMATETC iface, REFIID riid,
                                                               LPVOID* ppvObj);
static ULONG WINAPI OLEClipbrd_IEnumFORMATETC_AddRef(LPENUMFORMATETC iface);
static ULONG WINAPI OLEClipbrd_IEnumFORMATETC_Release(LPENUMFORMATETC iface);
static HRESULT WINAPI OLEClipbrd_IEnumFORMATETC_Next(LPENUMFORMATETC iface, ULONG celt,
                                                     FORMATETC* rgelt, ULONG* pceltFethed);
static HRESULT WINAPI OLEClipbrd_IEnumFORMATETC_Skip(LPENUMFORMATETC iface, ULONG celt);
static HRESULT WINAPI OLEClipbrd_IEnumFORMATETC_Reset(LPENUMFORMATETC iface);
static HRESULT WINAPI OLEClipbrd_IEnumFORMATETC_Clone(LPENUMFORMATETC iface, LPENUMFORMATETC* ppenum);


/*
 * Virtual function table for the OLEClipbrd's exposed IDataObject interface
 */
static ICOM_VTABLE(IDataObject) OLEClipbrd_IDataObject_VTable =
{
  ICOM_MSVTABLE_COMPAT_DummyRTTIVALUE
  OLEClipbrd_IDataObject_QueryInterface,
  OLEClipbrd_IDataObject_AddRef,
  OLEClipbrd_IDataObject_Release,
  OLEClipbrd_IDataObject_GetData,
  OLEClipbrd_IDataObject_GetDataHere,
  OLEClipbrd_IDataObject_QueryGetData,
  OLEClipbrd_IDataObject_GetCanonicalFormatEtc,
  OLEClipbrd_IDataObject_SetData,
  OLEClipbrd_IDataObject_EnumFormatEtc,
  OLEClipbrd_IDataObject_DAdvise,
  OLEClipbrd_IDataObject_DUnadvise,
  OLEClipbrd_IDataObject_EnumDAdvise
};

/*
 * Virtual function table for IEnumFORMATETC interface
 */
static struct ICOM_VTABLE(IEnumFORMATETC) efvt =
{
  ICOM_MSVTABLE_COMPAT_DummyRTTIVALUE
  OLEClipbrd_IEnumFORMATETC_QueryInterface,
  OLEClipbrd_IEnumFORMATETC_AddRef,
  OLEClipbrd_IEnumFORMATETC_Release,
  OLEClipbrd_IEnumFORMATETC_Next,
  OLEClipbrd_IEnumFORMATETC_Skip,
  OLEClipbrd_IEnumFORMATETC_Reset,
  OLEClipbrd_IEnumFORMATETC_Clone
};

/*
 * Name of our registered OLE clipboard window class 
 */
CHAR OLEClipbrd_WNDCLASS[] = "CLIPBRDWNDCLASS";

/*
 *  If we need to store state info we can store it here.
 *  For now we dont need this functionality.
 *
typedef struct tagClipboardWindowInfo
{
} ClipboardWindowInfo;
 */

/*---------------------------------------------------------------------*
 *           Win32 OLE clipboard API 
 *---------------------------------------------------------------------*/

/***********************************************************************
 *           OleSetClipboard     [OLE32.127]
 *  Places a pointer to the specified data object onto the clipboard,
 *  making the data object accessible to the OleGetClipboard function.
 *
 * RETURNS:
 *
 *    S_OK                  IDataObject pointer placed on the clipboard
 *    CLIPBRD_E_CANT_OPEN   OpenClipboard failed 
 *    CLIPBRD_E_CANT_EMPTY  EmptyClipboard failed 
 *    CLIPBRD_E_CANT_CLOSE  CloseClipboard failed
 *    CLIPBRD_E_CANT_SET    SetClipboard failed
 */

HRESULT WINAPI OleSetClipboard(IDataObject* pDataObj)
{
  HRESULT hr = S_OK;
  IEnumFORMATETC* penumFormatetc = NULL;
  FORMATETC rgelt;
  BOOL bClipboardOpen = FALSE;
/*
  HGLOBAL hDataObject = 0;
  OLEClipbrd **ppDataObject;
*/
  
  TRACE("(%p)\n", pDataObj);
  
  /*
   * Make sure we have a clipboard object
   */
  OLEClipbrd_Initialize();

  /*
   * If the Ole clipboard window hasn't been created yet, create it now.
   */
  if ( !theOleClipboard->hWndClipboard )
    theOleClipboard->hWndClipboard = OLEClipbrd_CreateWindow();

  if ( !theOleClipboard->hWndClipboard ) /* sanity check */
    HANDLE_ERROR( E_FAIL );

  /*
   * Open the Windows clipboard, associating it with our hidden window
   */
  if ( !(bClipboardOpen = OpenClipboard(theOleClipboard->hWndClipboard)) )
    HANDLE_ERROR( CLIPBRD_E_CANT_OPEN );

  /*
   * Empty the current clipboard and make our window the clipboard owner
   * NOTE: This will trigger a WM_DESTROYCLIPBOARD message 
   */
  if ( !EmptyClipboard() )
    HANDLE_ERROR( CLIPBRD_E_CANT_EMPTY );

  /*
   * If we are already holding on to an IDataObject first release that.
   */
  if ( theOleClipboard->pIDataObjectSrc )
  {
    IDataObject_Release(theOleClipboard->pIDataObjectSrc);
    theOleClipboard->pIDataObjectSrc = NULL;
  }

  /*
   * AddRef the data object passed in and save its pointer.
   * A NULL value indicates that the clipboard should be emptied.
   */
  theOleClipboard->pIDataObjectSrc = pDataObj;
  if ( pDataObj )
  {
    IDataObject_AddRef(theOleClipboard->pIDataObjectSrc);
  }

  /*
   * Enumerate all HGLOBAL formats supported by the source and make 
   * those formats available using delayed rendering using SetClipboardData.
   * Only global memory based data items may be made available to non-OLE 
   * applications via the standard Windows clipboard API. Data based on other 
   * mediums(non TYMED_HGLOBAL) can only be accessed via the Ole Clipboard API.
   *
   * TODO: Do we need to additionally handle TYMED_IStorage media by copying
   * the storage into global memory?
   */
  if ( pDataObj )
  {
    if ( FAILED(hr = IDataObject_EnumFormatEtc( pDataObj,
                                                DATADIR_GET,
                                                &penumFormatetc )))
    {
      HANDLE_ERROR( hr );
    }
      
    while ( S_OK == IEnumFORMATETC_Next(penumFormatetc, 1, &rgelt, NULL) )
    {
      if ( rgelt.tymed == TYMED_HGLOBAL )
      {
        CHAR szFmtName[80];
        TRACE("(cfFormat=%d:%s)\n", rgelt.cfFormat,
              GetClipboardFormatNameA(rgelt.cfFormat, szFmtName, sizeof(szFmtName)-1)
                ? szFmtName : "");
  
        SetClipboardData( rgelt.cfFormat, (HANDLE)NULL);
      }
    }
    IEnumFORMATETC_Release(penumFormatetc);
  }

  /*
   * Windows additionally creates a new "DataObject" clipboard format
   * and stores in on the clipboard. We could possibly store a pointer 
   * to our internal IDataObject interface on the clipboard. I'm not
   * sure what the use of this is though.
   * Enable the code below for this functionality.
   */
/*
   theOleClipboard->cfDataObj = RegisterClipboardFormatA("DataObject");
   hDataObject = GlobalAlloc( GMEM_DDESHARE|GMEM_MOVEABLE|GMEM_ZEROINIT,
                             sizeof(OLEClipbrd *));
   if (hDataObject==0)
     HANDLE_ERROR( E_OUTOFMEMORY );
   
   ppDataObject = (OLEClipbrd**)GlobalLock(hDataObject);
   *ppDataObject = theOleClipboard;
   GlobalUnlock(hDataObject);

   if ( !SetClipboardData( theOleClipboard->cfDataObj, hDataObject ) )
     HANDLE_ERROR( CLIPBRD_E_CANT_SET );
*/
  
  hr = S_OK;

CLEANUP:

  /*
   * Close Windows clipboard (It remains associated with our window)
   */
  if ( bClipboardOpen && !CloseClipboard() )
    hr = CLIPBRD_E_CANT_CLOSE;

  /*
   * Release the source IDataObject if something failed
   */
  if ( FAILED(hr) )
  {
    if (theOleClipboard->pIDataObjectSrc)
    {
      IDataObject_Release(theOleClipboard->pIDataObjectSrc);
      theOleClipboard->pIDataObjectSrc = NULL;
    }
  }

  return hr;
}


/***********************************************************************
 * OleGetClipboard32 [OLE32.105]
 * Returns a pointer to our internal IDataObject which represents the conceptual 
 * state of the Windows clipboard. If the current clipboard already contains 
 * an IDataObject, our internal IDataObject will delegate to this object.
 */
HRESULT WINAPI OleGetClipboard(IDataObject** ppDataObj)
{
  HRESULT hr = S_OK;
  TRACE("()\n");
    
  /*
   * Make sure we have a clipboard object
   */
  OLEClipbrd_Initialize();

  if (!theOleClipboard)
    return E_OUTOFMEMORY;

  /* Return a reference counted IDataObject */
  hr = IDataObject_QueryInterface( (IDataObject*)&(theOleClipboard->lpvtbl1),
                                   &IID_IDataObject,  (void**)ppDataObj);
  return hr;
}

/***********************************************************************
 *           OleFlushClipboard   [OLE2.76]
 */

HRESULT WINAPI OleFlushClipboard16(void)

{
  return OleFlushClipboard();
}


/******************************************************************************
 *              OleFlushClipboard        [OLE32.103]
 *  Renders the data from the source IDataObject into the windows clipboard
 *
 *  TODO: OleFlushClipboard needs to additionally handle TYMED_IStorage media
 *  by copying the storage into global memory. Subsequently the default
 *  data object exposed through OleGetClipboard must convert this TYMED_HGLOBAL
 *  back to TYMED_IStorage.
 */
HRESULT WINAPI OleFlushClipboard()
{
  IEnumFORMATETC* penumFormatetc = NULL;
  FORMATETC rgelt;
  HRESULT hr = S_OK;
  BOOL bClipboardOpen = FALSE;
  
  TRACE("()\n");

  /*
   * Make sure we have a clipboard object
   */
  OLEClipbrd_Initialize();

  /*
   * Already flushed or no source DataObject? Nothing to do.
   */
  if (!theOleClipboard->pIDataObjectSrc)
    return S_OK;

  /*
   * Open the Windows clipboard
   */
  if ( !(bClipboardOpen = OpenClipboard(theOleClipboard->hWndClipboard)) )
    HANDLE_ERROR( CLIPBRD_E_CANT_OPEN );

  /*
   * Empty the current clipboard
   */
  if ( !EmptyClipboard() )
    HANDLE_ERROR( CLIPBRD_E_CANT_EMPTY );

  /*
   * Render all HGLOBAL formats supported by the source into
   * the windows clipboard.
   */
  if ( FAILED( hr = IDataObject_EnumFormatEtc( (IDataObject*)&(theOleClipboard->lpvtbl1),
                                               DATADIR_GET,
                                               &penumFormatetc) ))
  {
    HANDLE_ERROR( hr );
  }

  while ( S_OK == IEnumFORMATETC_Next(penumFormatetc, 1, &rgelt, NULL) )
  {
    if ( rgelt.tymed == TYMED_HGLOBAL )
    {
      CHAR szFmtName[80];
      TRACE("(cfFormat=%d:%s)\n", rgelt.cfFormat,
            GetClipboardFormatNameA(rgelt.cfFormat, szFmtName, sizeof(szFmtName)-1)
              ? szFmtName : "");

      /*
       * Render the clipboard data
       */
      if ( FAILED(OLEClipbrd_RenderFormat( &rgelt )) )
        continue;
    }
  }
  
  IEnumFORMATETC_Release(penumFormatetc);
  
  /*
   * Release the data object we are holding on to
   */
  if ( theOleClipboard->pIDataObjectSrc )
  {
    IDataObject_Release(theOleClipboard->pIDataObjectSrc);
    theOleClipboard->pIDataObjectSrc = NULL;
  }

CLEANUP:

  /*
   * Close Windows clipboard (It remains associated with our window)
   */
  if ( bClipboardOpen && !CloseClipboard() )
    hr = CLIPBRD_E_CANT_CLOSE;

  return hr;
}


/***********************************************************************
 *           OleIsCurrentClipboard32 [OLE32.110]
 */
HRESULT WINAPI OleIsCurrentClipboard (  IDataObject *pDataObject) 
{
  TRACE("()\n");
  /*
   * Make sure we have a clipboard object
   */
  OLEClipbrd_Initialize();

  if (!theOleClipboard)
    return E_OUTOFMEMORY;

  return (pDataObject == theOleClipboard->pIDataObjectSrc) ? S_OK : S_FALSE;
}


/*---------------------------------------------------------------------*
 *           Internal implementation methods for the OLE clipboard 
 *---------------------------------------------------------------------*/

/***********************************************************************
 * OLEClipbrd_Initialize()
 * Initializes the OLE clipboard. 
 */
void OLEClipbrd_Initialize()
{
  /*
   * Create the clipboard if necesary 
   */
  if ( !theOleClipboard )
  {
    TRACE("()\n");
    theOleClipboard = OLEClipbrd_Construct();
  }
}


/***********************************************************************
 * OLEClipbrd_UnInitialize()
 * Un-Initializes the OLE clipboard 
 */
void OLEClipbrd_UnInitialize()
{
  TRACE("()\n");
  /*
   * Destroy the clipboard if no one holds a reference to us.
   * Note that the clipboard was created with a reference count of 1.
   */
  if ( theOleClipboard && (theOleClipboard->ref <= 1) )
  {
    OLEClipbrd_Destroy( theOleClipboard );
  }
  else
  {
    WARN( "() : OLEClipbrd_UnInitialize called while client holds an IDataObject reference!\n");
  }
}


/*********************************************************
 * Construct the OLEClipbrd class.
 */
static OLEClipbrd* OLEClipbrd_Construct()
{
  OLEClipbrd* newObject = NULL;
  HGLOBAL hNewObject = 0;
  
  /*
   * Allocate space for the object. We use GlobalAlloc since we need
   * an HGLOBAL to expose our DataObject as a registered clipboard type.
   */
  hNewObject = GlobalAlloc( GMEM_DDESHARE|GMEM_MOVEABLE|GMEM_ZEROINIT,
                           sizeof(OLEClipbrd));
  if (hNewObject==0)
    return NULL;

  /*
   * Lock the handle for the entire lifetime of the clipboard.
   */
  newObject = GlobalLock(hNewObject);
  
  /*
   * Initialize the virtual function table.
   */
  newObject->lpvtbl1 = &OLEClipbrd_IDataObject_VTable;

  /*
   * Start with one reference count. The caller of this function 
   * must release the interface pointer when it is done.
   */
  newObject->ref = 1;

  newObject->hSelf = hNewObject;
  
  /*
   * The Ole clipboard is a singleton - save the global handle and pointer
   */
  theOleClipboard = newObject;
  hTheOleClipboard = hNewObject;

  return theOleClipboard;
}

static void OLEClipbrd_Destroy(OLEClipbrd* ptrToDestroy)
{
  TRACE("()\n");
    
  if ( !ptrToDestroy )
    return;

  /*
   * Destroy the Ole clipboard window 
   */
  if ( ptrToDestroy->hWndClipboard )
    OLEClipbrd_DestroyWindow(ptrToDestroy->hWndClipboard);

  /*
   * Free the actual OLE Clipboard structure.
   */
  TRACE("() - Destroying clipboard data object.\n");
  GlobalUnlock(ptrToDestroy->hSelf);
  GlobalFree(ptrToDestroy->hSelf);

  /*
   * The Ole clipboard is a singleton (ptrToDestroy == theOleClipboard)
   */
  theOleClipboard = NULL;
  hTheOleClipboard = 0;
}


/***********************************************************************
 * OLEClipbrd_CreateWindow()
 * Create the clipboard window 
 */
static HWND OLEClipbrd_CreateWindow()
{
  HWND hwnd = 0;
  WNDCLASSEXA wcex;
  ATOM atom;

  /* 
   * Register the clipboard window class if necessary 
   */

  if ( !( atom = GlobalFindAtomA(OLEClipbrd_WNDCLASS) ) ||
        !( CLASS_FindClassByAtom(atom, 0) ) )
  {
    ZeroMemory( &wcex, sizeof(WNDCLASSEXA));

    wcex.cbSize         = sizeof(WNDCLASSEXA);
    /* Windows creates this class with a style mask of 0
     * We dont bother doing this since the FindClassByAtom code
     * would have to be changed to deal with this idiosyncracy. */
    wcex.style          = CS_GLOBALCLASS;
    wcex.lpfnWndProc    = (WNDPROC)OLEClipbrd_WndProc;
    wcex.hInstance      = 0;
    wcex.lpszClassName  = OLEClipbrd_WNDCLASS;

    RegisterClassExA(&wcex);
  }

  /*
   * Create a hidden window to receive OLE clipboard messages 
   */

/*
 *  If we need to store state info we can store it here.
 *  For now we dont need this functionality.
 *   ClipboardWindowInfo clipboardInfo;
 *   ZeroMemory( &trackerInfo, sizeof(ClipboardWindowInfo));
 */

  hwnd = CreateWindowA(OLEClipbrd_WNDCLASS, 
				    "ClipboardWindow",
				    WS_POPUP | WS_CLIPSIBLINGS | WS_OVERLAPPED,
				    CW_USEDEFAULT, CW_USEDEFAULT,
				    CW_USEDEFAULT, CW_USEDEFAULT,
				    0,
				    0,
				    0,
				    0 /*(LPVOID)&clipboardInfo */);

  return hwnd;
}

/***********************************************************************
 * OLEClipbrd_DestroyWindow(HWND)
 * Destroy the clipboard window and unregister its class
 */
static void OLEClipbrd_DestroyWindow(HWND hwnd)
{
  /* 
   * Destroy clipboard window and unregister its WNDCLASS 
   */
  DestroyWindow(hwnd);
  UnregisterClassA( OLEClipbrd_WNDCLASS, 0 );
}

/***********************************************************************
 * OLEClipbrd_WndProc(HWND, unsigned, WORD, LONG)
 * Processes messages sent to the OLE clipboard window. 
 * Note that we will intercept messages in our WndProc only when data 
 * has been placed in the clipboard via OleSetClipboard(). 
 * i.e. Only when OLE owns the windows clipboard.
 */
LRESULT CALLBACK OLEClipbrd_WndProc
  (HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
  switch (message) 
  {
    /*
     * WM_RENDERFORMAT 
     * We receive this message to allow us to handle delayed rendering of
     * a specific clipboard format when an application requests data in 
     * that format by calling GetClipboardData.
     * (Recall that in OleSetClipboard, we used SetClipboardData to 
     * make all HGLOBAL formats supported by the source IDataObject
     * available using delayed rendering)
     * On receiving this mesage we must actually render the data in the 
     * specified format and place it on the clipboard by calling the 
     * SetClipboardData function. 
     */
    case WM_RENDERFORMAT:
    {
      FORMATETC rgelt;
        
      ZeroMemory( &rgelt, sizeof(FORMATETC));

      /*
       * Initialize FORMATETC to a Windows clipboard friendly format
       */
      rgelt.cfFormat = (UINT) wParam;
      rgelt.dwAspect = DVASPECT_CONTENT;
      rgelt.lindex = -1;
      rgelt.tymed = TYMED_HGLOBAL;

      TRACE("(): WM_RENDERFORMAT(cfFormat=%d)\n", rgelt.cfFormat);
      
      /*
       * Render the clipboard data.
       * (We must have a source data object or we wouldn't be in this WndProc)
       */
      OLEClipbrd_RenderFormat( &rgelt );

      break;
    }

    /*
     * WM_RENDERALLFORMATS
     * Sent before the clipboard owner window is destroyed.
     * We should receive this message only when OleUninitialize is called
     * while we have an IDataObject in the clipboard.
     * For the content of the clipboard to remain available to other
     * applications, we must render data in all the formats the source IDataObject
     * is capable of generating, and place the data on the clipboard by calling
     * SetClipboardData.
     */
    case WM_RENDERALLFORMATS:
    {
      IEnumFORMATETC* penumFormatetc = NULL;
      FORMATETC rgelt;
      
      TRACE("(): WM_RENDERALLFORMATS\n");
      
      /*
       * Render all HGLOBAL formats supported by the source into
       * the windows clipboard.
       */
      if ( FAILED( IDataObject_EnumFormatEtc( (IDataObject*)&(theOleClipboard->lpvtbl1),
                                 DATADIR_GET, &penumFormatetc) ) )
      {
        WARN("(): WM_RENDERALLFORMATS failed to retrieve EnumFormatEtc!\n");
        return 0;
      }
      
      while ( S_OK == IEnumFORMATETC_Next(penumFormatetc, 1, &rgelt, NULL) )
      {
        if ( rgelt.tymed == TYMED_HGLOBAL )
        {
          /*
           * Render the clipboard data. 
           */
          if ( FAILED(OLEClipbrd_RenderFormat( &rgelt )) )
            continue;
        
          TRACE("(): WM_RENDERALLFORMATS(cfFormat=%d)\n", rgelt.cfFormat);
        }
      }
      
      IEnumFORMATETC_Release(penumFormatetc);

      break;
    }

    /*
     * WM_DESTROYCLIPBOARD
     * This is sent by EmptyClipboard before the clipboard is emptied.
     * We should release any IDataObject we are holding onto when we receive
     * this message, since it indicates that the OLE clipboard should be empty
     * from this point on.
     */
    case WM_DESTROYCLIPBOARD:
    {
      TRACE("(): WM_DESTROYCLIPBOARD\n");
      /*
       * Release the data object we are holding on to
       */
      if ( theOleClipboard->pIDataObjectSrc )
      {
        IDataObject_Release(theOleClipboard->pIDataObjectSrc);
        theOleClipboard->pIDataObjectSrc = NULL;
      }
      break;
    }

/*
    case WM_ASKCBFORMATNAME:
    case WM_CHANGECBCHAIN:
    case WM_DRAWCLIPBOARD:
    case WM_SIZECLIPBOARD:
    case WM_HSCROLLCLIPBOARD:
    case WM_VSCROLLCLIPBOARD:
    case WM_PAINTCLIPBOARD:
*/
    default:
      return DefWindowProcA(hWnd, message, wParam, lParam);
  }

  return 0;
}


/***********************************************************************
 * OLEClipbrd_RenderFormat(LPFORMATETC)
 * Render the clipboard data. Note that this call will delegate to the
 * source data object.
 * Note: This function assumes it is passed an HGLOBAL format to render.
 */
static HRESULT OLEClipbrd_RenderFormat(LPFORMATETC pFormatetc)
{
  STGMEDIUM medium;
  HGLOBAL hDup;
  HRESULT hr = S_OK;
  
  if ( FAILED(hr = IDataObject_GetData((IDataObject*)&(theOleClipboard->lpvtbl1),
                                       pFormatetc, &medium)) )
  {
    WARN("() : IDataObject_GetData failed to render clipboard data! (%lx)\n", hr);
    return hr;
  }

  /*
   *  Put a copy of the rendered data back on the clipboard
   */
  
  if ( !(hDup = OLEClipbrd_GlobalDupMem(medium.u.hGlobal)) )
    HANDLE_ERROR( E_OUTOFMEMORY );
       
  if ( !SetClipboardData( pFormatetc->cfFormat, hDup ) )
  {
    GlobalFree(hDup);
    WARN("() : Failed to set rendered clipboard data into clipboard!\n");
  }

CLEANUP:
  
  ReleaseStgMedium(&medium);
  
  return hr;
}


/***********************************************************************
 * OLEClipbrd_GlobalDupMem( HGLOBAL )
 * Helper method to duplicate an HGLOBAL chunk of memory
 */
static HGLOBAL OLEClipbrd_GlobalDupMem( HGLOBAL hGlobalSrc )
{
    HGLOBAL hGlobalDest;
    PVOID pGlobalSrc, pGlobalDest;
    DWORD cBytes;
    
    if ( !hGlobalSrc )
      return 0;

    cBytes = GlobalSize(hGlobalSrc);
    if ( 0 == cBytes )
      return 0;
        
    hGlobalDest = GlobalAlloc( GMEM_DDESHARE|GMEM_MOVEABLE,
                               cBytes );
    if ( !hGlobalDest )
      return 0;
    
    pGlobalSrc = GlobalLock(hGlobalSrc);
    pGlobalDest = GlobalLock(hGlobalDest);
    if ( !pGlobalSrc || !pGlobalDest )
      return 0;

    memcpy(pGlobalDest, pGlobalSrc, cBytes);
        
    GlobalUnlock(hGlobalSrc);
    GlobalUnlock(hGlobalDest);

    return hGlobalDest;
}


/*---------------------------------------------------------------------*
 *  Implementation of the internal IDataObject interface exposed by 
 *  the OLE clipboard.
 *---------------------------------------------------------------------*/


/************************************************************************
 * OLEClipbrd_IDataObject_QueryInterface (IUnknown)
 *
 * See Windows documentation for more details on IUnknown methods.
 */
static HRESULT WINAPI OLEClipbrd_IDataObject_QueryInterface(
            IDataObject*     iface,
            REFIID           riid,
            void**           ppvObject)
{
  /* 
   * Declare "This" pointer 
   */
  ICOM_THIS(OLEClipbrd, iface);
  char    xriid[50];

  WINE_StringFromCLSID((LPCLSID)riid,xriid);
  TRACE("(%p)->(\n\tIID:\t%s,%p)\n",This,xriid,ppvObject);
  
  /*
   * Perform a sanity check on the parameters.
   */
  if ( (This==0) || (ppvObject==0) )
    return E_INVALIDARG;
  
  /*
   * Initialize the return parameter.
   */
  *ppvObject = 0;

  /*
   * Compare the riid with the interface IDs implemented by this object.
   */
  if (memcmp(&IID_IUnknown, riid, sizeof(IID_IUnknown)) == 0) 
  {
    *ppvObject = iface;
  }
  else if (memcmp(&IID_IDataObject, riid, sizeof(IID_IDataObject)) == 0) 
  {
    *ppvObject = (IDataObject*)&(This->lpvtbl1);
  }
  else  /* We only support IUnknown and IDataObject */
  {
    char clsid[50];

    WINE_StringFromCLSID((LPCLSID)riid,clsid);
    WARN( "() : asking for unsupported interface %s\n", clsid);

    return E_NOINTERFACE;
  }
  
  /*
   * Query Interface always increases the reference count by one when it is
   * successful. 
   */
  IUnknown_AddRef((IUnknown*)*ppvObject);

  return S_OK;
}

/************************************************************************
 * OLEClipbrd_IDataObject_AddRef (IUnknown)
 *
 * See Windows documentation for more details on IUnknown methods.
 */
static ULONG WINAPI OLEClipbrd_IDataObject_AddRef( 
            IDataObject*     iface)
{
  /* 
   * Declare "This" pointer 
   */
  ICOM_THIS(OLEClipbrd, iface);

  TRACE("(%p)->(count=%lu)\n",This, This->ref);
  
  This->ref++;

  return This->ref;
}

/************************************************************************
 * OLEClipbrd_IDataObject_Release (IUnknown)
 *
 * See Windows documentation for more details on IUnknown methods.
 */
static ULONG WINAPI OLEClipbrd_IDataObject_Release( 
            IDataObject*     iface)
{
  /* 
   * Declare "This" pointer 
   */
  ICOM_THIS(OLEClipbrd, iface);

  TRACE("(%p)->(count=%lu)\n",This, This->ref);
  
  /*
   * Decrease the reference count on this object.
   */
  This->ref--;

  /*
   * If the reference count goes down to 0, perform suicide.
   */
  if (This->ref==0)
  {
    OLEClipbrd_Destroy(This);
  }
  
  return This->ref;
}

 
/************************************************************************
 * OLEClipbrd_IDataObject_GetData (IDataObject)
 *
 * The OLE Clipboard's implementation of this method delegates to 
 * a data source if there is one or wraps around the windows clipboard
 *
 * See Windows documentation for more details on IDataObject methods.
 */
static HRESULT WINAPI OLEClipbrd_IDataObject_GetData(
	    IDataObject*     iface,
	    LPFORMATETC      pformatetcIn, 
	    STGMEDIUM*       pmedium)
{
  HANDLE      hData = 0;
  /*
   * Declare "This" pointer 
   */
  ICOM_THIS(OLEClipbrd, iface);

  if ( !pformatetcIn || !pformatetcIn || !pmedium )
    return E_INVALIDARG;

  TRACE("(%p, %p)\n", iface, pformatetcIn);

  /*
   * If we have a data source placed on the clipboard (via OleSetClipboard)
   * simply delegate to the source object's QueryGetData
   * NOTE: This code assumes that the IDataObject is in the same address space!
   * We will need to add marshalling support when Wine handles multiple processes.
   */
  if ( This->pIDataObjectSrc )
  {
    return IDataObject_GetData(This->pIDataObjectSrc, pformatetcIn, pmedium);
  }

  if ( pformatetcIn->lindex != -1 )
    return DV_E_LINDEX;
  if ( (pformatetcIn->tymed & TYMED_HGLOBAL) != TYMED_HGLOBAL )
    return DV_E_TYMED;
/*
   if ( pformatetcIn->dwAspect != DVASPECT_CONTENT )
     return DV_E_DVASPECT;
*/

  /* 
   * Otherwise, delegate to the Windows clipboard function GetClipboardData
   */
  hData = GetClipboardData(pformatetcIn->cfFormat);

  /* 
   * Return the clipboard data in the storage medium structure
   */
  pmedium->tymed = (hData == 0) ? TYMED_NULL : TYMED_HGLOBAL;
  pmedium->u.hGlobal = (HGLOBAL)hData;
  pmedium->pUnkForRelease = NULL;
  
  return (hData == 0) ? DV_E_FORMATETC : S_OK;
}

static HRESULT WINAPI OLEClipbrd_IDataObject_GetDataHere(
	    IDataObject*     iface, 
	    LPFORMATETC      pformatetc,
	    STGMEDIUM*       pmedium)
{
  FIXME(": Stub\n");
  return E_NOTIMPL;
}

/************************************************************************
 * OLEClipbrd_IDataObject_QueryGetData (IDataObject)
 *
 * The OLE Clipboard's implementation of this method delegates to 
 * a data source if there is one or wraps around the windows clipboard
 * function IsClipboardFormatAvailable() otherwise.
 *
 * See Windows documentation for more details on IDataObject methods.
 */
static HRESULT WINAPI OLEClipbrd_IDataObject_QueryGetData(
	    IDataObject*     iface,
	    LPFORMATETC      pformatetc)
{
  /* 
   * Declare "This" pointer 
   */
  ICOM_THIS(OLEClipbrd, iface);

  TRACE("(%p, %p)\n", iface, pformatetc);

  /*
   * If we have a data source placed on the clipboard (via OleSetClipboard)
   * simply delegate to the source object's QueryGetData
   */
  if ( This->pIDataObjectSrc )
  {
    return IDataObject_QueryGetData(This->pIDataObjectSrc, pformatetc);
  }

  if (!pformatetc)
    return E_INVALIDARG;
/*
   if ( pformatetc->dwAspect != DVASPECT_CONTENT )
     return DV_E_DVASPECT;
*/
  if ( pformatetc->lindex != -1 )
    return DV_E_LINDEX;

  /* TODO: Handle TYMED_IStorage media which were put on the clipboard
   * by copying the storage into global memory. We must convert this
   * TYMED_HGLOBAL back to TYMED_IStorage.
   */
  if ( pformatetc->tymed != TYMED_HGLOBAL )
    return DV_E_TYMED;
          
  /*
   * Delegate to the Windows clipboard function IsClipboardFormatAvailable
   */
  return (IsClipboardFormatAvailable(pformatetc->cfFormat)) ? S_OK : DV_E_FORMATETC;
}

/************************************************************************
 * OLEClipbrd_IDataObject_GetCanonicalFormatEtc (IDataObject)
 *
 * See Windows documentation for more details on IDataObject methods.
 */
static HRESULT WINAPI OLEClipbrd_IDataObject_GetCanonicalFormatEtc(
	    IDataObject*     iface, 
	    LPFORMATETC      pformatectIn, 
	    LPFORMATETC      pformatetcOut)
{
  TRACE("(%p, %p, %p)\n", iface, pformatectIn, pformatetcOut);

  if ( !pformatectIn || !pformatetcOut )
    return E_INVALIDARG;

  memcpy(pformatetcOut, pformatectIn, sizeof(FORMATETC));
  return DATA_S_SAMEFORMATETC;
}

/************************************************************************
 * OLEClipbrd_IDataObject_SetData (IDataObject)
 *
 * The OLE Clipboard's does not implement this method 
 *
 * See Windows documentation for more details on IDataObject methods.
 */
static HRESULT WINAPI OLEClipbrd_IDataObject_SetData(
	    IDataObject*     iface,
	    LPFORMATETC      pformatetc, 
	    STGMEDIUM*       pmedium, 
	    BOOL             fRelease)
{
  return E_NOTIMPL;
}

/************************************************************************
 * OLEClipbrd_IDataObject_EnumFormatEtc (IDataObject)
 *
 * See Windows documentation for more details on IDataObject methods.
 */
static HRESULT WINAPI OLEClipbrd_IDataObject_EnumFormatEtc(
	    IDataObject*     iface,
	    DWORD            dwDirection,
	    IEnumFORMATETC** ppenumFormatEtc)
{
  HRESULT hr = S_OK;
  FORMATETC *afmt = NULL;
  int cfmt, i;
  UINT format;
  BOOL bClipboardOpen;
  
  /* 
   * Declare "This" pointer 
   */
  ICOM_THIS(OLEClipbrd, iface);

  TRACE("(%p, %lx, %p)\n", iface, dwDirection, ppenumFormatEtc);

  /*
   * If we have a data source placed on the clipboard (via OleSetClipboard)
   * simply delegate to the source object's EnumFormatEtc
   */
  if ( This->pIDataObjectSrc )
  {
    return IDataObject_EnumFormatEtc(This->pIDataObjectSrc,
                                     dwDirection, ppenumFormatEtc);
  }

  /*
   * Otherwise we must provide our own enumerator which wraps around the
   * Windows clipboard function EnumClipboardFormats
   */
  if ( !ppenumFormatEtc )
    return E_INVALIDARG;

  if ( dwDirection != DATADIR_GET ) /* IDataObject_SetData not implemented */
    return E_NOTIMPL;

  /*
   * Store all current clipboard formats in an array of FORMATETC's,
   * and create an IEnumFORMATETC enumerator from this list.
   */
  cfmt = CountClipboardFormats();
  afmt = (FORMATETC *)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY,
                                sizeof(FORMATETC) * cfmt);
  /*
   * Open the Windows clipboard, associating it with our hidden window
   */
  if ( !(bClipboardOpen = OpenClipboard(This->hWndClipboard)) )
    HANDLE_ERROR( CLIPBRD_E_CANT_OPEN );

  /*
   * Store all current clipboard formats in an array of FORMATETC's
   * TODO: Handle TYMED_IStorage media which were put on the clipboard
   * by copying the storage into global memory. We must convert this
   * TYMED_HGLOBAL back to TYMED_IStorage.
   */
  for (i = 0, format = 0; i < cfmt; i++)
  {
    format = EnumClipboardFormats(format);
    if (!format)  /* Failed! */
    {
      ERR("EnumClipboardFormats failed to return format!\n");
      HANDLE_ERROR( E_FAIL );
    }
    
    /* Init the FORMATETC struct */
    afmt[i].cfFormat = format;
    afmt[i].ptd = NULL;
    afmt[i].dwAspect = DVASPECT_CONTENT;
    afmt[i].lindex = -1;
    afmt[i].tymed = TYMED_HGLOBAL;
  }

  /*
   * Create an EnumFORMATETC enumerator and return an
   * EnumFORMATETC after bumping up its ref count
   */
  *ppenumFormatEtc = OLEClipbrd_IEnumFORMATETC_Construct( cfmt, afmt, (LPUNKNOWN)iface);
  if (!(*ppenumFormatEtc))
    HANDLE_ERROR( E_OUTOFMEMORY );

  if (FAILED( hr = IEnumFORMATETC_AddRef(*ppenumFormatEtc)))
    HANDLE_ERROR( hr );
      
  hr = S_OK;
  
CLEANUP:
  /*
   * Free the array of FORMATETC's
   */
  if (afmt)
    HeapFree(GetProcessHeap(), 0, afmt);
  
  /*
   * Close Windows clipboard
   */
  if ( bClipboardOpen && !CloseClipboard() )
    hr = CLIPBRD_E_CANT_CLOSE;

  return hr;
}

/************************************************************************
 * OLEClipbrd_IDataObject_DAdvise (IDataObject)
 *
 * The OLE Clipboard's does not implement this method 
 *
 * See Windows documentation for more details on IDataObject methods.
 */
static HRESULT WINAPI OLEClipbrd_IDataObject_DAdvise(
	    IDataObject*     iface, 
	    FORMATETC*       pformatetc, 
	    DWORD            advf, 
	    IAdviseSink*     pAdvSink, 
	    DWORD*           pdwConnection)
{
  return E_NOTIMPL;
}

/************************************************************************
 * OLEClipbrd_IDataObject_DUnadvise (IDataObject)
 *
 * The OLE Clipboard's does not implement this method 
 *
 * See Windows documentation for more details on IDataObject methods.
 */
static HRESULT WINAPI OLEClipbrd_IDataObject_DUnadvise(
	    IDataObject*     iface,
	    DWORD            dwConnection)
{
  return E_NOTIMPL;
}

/************************************************************************
 * OLEClipbrd_IDataObject_EnumDAdvise (IDataObject)
 *
 * The OLE Clipboard does not implement this method
 *
 * See Windows documentation for more details on IDataObject methods.
 */
static HRESULT WINAPI OLEClipbrd_IDataObject_EnumDAdvise(
	    IDataObject*     iface,
	    IEnumSTATDATA**  ppenumAdvise)
{
  return E_NOTIMPL;
}


/*---------------------------------------------------------------------*
 *  Implementation of the internal IEnumFORMATETC interface returned by
 *  the OLE clipboard's IDataObject.
 *---------------------------------------------------------------------*/

/************************************************************************
 * OLEClipbrd_IEnumFORMATETC_Construct (UINT, const FORMATETC, LPUNKNOWN)
 *
 * Creates an IEnumFORMATETC enumerator from an array of FORMATETC
 * Structures. pUnkOuter is the outer unknown for reference counting only.
 * NOTE: this does not AddRef the interface.
 */

LPENUMFORMATETC OLEClipbrd_IEnumFORMATETC_Construct(UINT cfmt, const FORMATETC afmt[],
                                                    LPUNKNOWN pUnkDataObj)
{
  IEnumFORMATETCImpl* ef;
  DWORD size=cfmt * sizeof(FORMATETC);
  LPMALLOC pIMalloc;
  
  ef = (IEnumFORMATETCImpl*)HeapAlloc(GetProcessHeap(),
                                      HEAP_ZERO_MEMORY,
                                      sizeof(IEnumFORMATETCImpl));
  if (!ef)
    return NULL;
  
  ef->ref = 0;
  ef->lpvtbl = &efvt;
  ef->pUnkDataObj = pUnkDataObj;
  
  ef->posFmt = 0;
  ef->countFmt = cfmt;
  if (FAILED(CoGetMalloc(MEMCTX_TASK, &pIMalloc)))
    return NULL;
  ef->pFmt = (LPFORMATETC)IMalloc_Alloc(pIMalloc, size);
  IMalloc_Release(pIMalloc);
  
  if (ef->pFmt)
    memcpy(ef->pFmt, afmt, size);
  
  TRACE("(%p)->()\n",ef);
  return (LPENUMFORMATETC)ef;
}


/************************************************************************
 * OLEClipbrd_IEnumFORMATETC_QueryInterface (IUnknown)
 *
 * See Windows documentation for more details on IUnknown methods.
 */
static HRESULT WINAPI OLEClipbrd_IEnumFORMATETC_QueryInterface
  (LPENUMFORMATETC iface, REFIID riid, LPVOID* ppvObj)
{
  ICOM_THIS(IEnumFORMATETCImpl,iface);
  char    xriid[50];

  WINE_StringFromCLSID((LPCLSID)riid,xriid);
  TRACE("(%p)->(\n\tIID:\t%s,%p)\n",This,xriid,ppvObj);

  /*
   * Since enumerators are seperate objects from the parent data object
   * we only need to support the IUnknown and IEnumFORMATETC interfaces
   */
  
  *ppvObj = NULL;
  
  if(IsEqualIID(riid, &IID_IUnknown))
  {
    *ppvObj = This;
  }
  else if(IsEqualIID(riid, &IID_IEnumFORMATETC))
  {
    *ppvObj = (IDataObject*)This;
  }   
  
  if(*ppvObj)
  {
    IEnumFORMATETC_AddRef((IEnumFORMATETC*)*ppvObj);
    TRACE("-- Interface: (%p)->(%p)\n",ppvObj,*ppvObj);
    return S_OK;
  }
  
  TRACE("-- Interface: E_NOINTERFACE\n");
  return E_NOINTERFACE;
}

/************************************************************************
 * OLEClipbrd_IEnumFORMATETC_AddRef (IUnknown)
 *
 * Since enumerating formats only makes sense when our data object is around,
 * we insure that it stays as long as we stay by calling our parents IUnknown
 * for AddRef and Release. But since we are not controlled by the lifetime of
 * the outer object, we still keep our own reference count in order to
 * free ourselves.
 */
static ULONG WINAPI OLEClipbrd_IEnumFORMATETC_AddRef(LPENUMFORMATETC iface)
{
  ICOM_THIS(IEnumFORMATETCImpl,iface);
  TRACE("(%p)->(count=%lu)\n",This, This->ref);

  if (This->pUnkDataObj)
    IUnknown_AddRef(This->pUnkDataObj);
  
  return ++(This->ref);
}

/************************************************************************
 * OLEClipbrd_IEnumFORMATETC_Release (IUnknown)
 *
 * See Windows documentation for more details on IUnknown methods.
 */
static ULONG WINAPI OLEClipbrd_IEnumFORMATETC_Release(LPENUMFORMATETC iface)
{
  ICOM_THIS(IEnumFORMATETCImpl,iface);
  LPMALLOC pIMalloc;

  TRACE("(%p)->(count=%lu)\n",This, This->ref);

  if (This->pUnkDataObj)
    IUnknown_Release(This->pUnkDataObj);  /* Release parent data object */
  
  if (!--(This->ref)) 
  {
    TRACE("() - destroying IEnumFORMATETC(%p)\n",This);
    if (SUCCEEDED(CoGetMalloc(MEMCTX_TASK, &pIMalloc)))
    {
      IMalloc_Free(pIMalloc, This->pFmt);
      IMalloc_Release(pIMalloc);
    }
      
    HeapFree(GetProcessHeap(),0,This);
    return 0;
  }

  return This->ref;
}

/************************************************************************
 * OLEClipbrd_IEnumFORMATETC_Next (IEnumFORMATETC)
 *
 * Standard enumerator members for IEnumFORMATETC
 */
static HRESULT WINAPI OLEClipbrd_IEnumFORMATETC_Next
  (LPENUMFORMATETC iface, ULONG celt, FORMATETC *rgelt, ULONG *pceltFethed)
{
  ICOM_THIS(IEnumFORMATETCImpl,iface);
  UINT cfetch;
  HRESULT hres = S_FALSE;
  
  TRACE("(%p)->(pos=%u)\n", This, This->posFmt);
  
  if (This->posFmt < This->countFmt)
  {
    cfetch = This->countFmt - This->posFmt;
    if (cfetch >= celt)
    {
      cfetch = celt;
      hres = S_OK;
    }
    
    memcpy(rgelt, &This->pFmt[This->posFmt], cfetch * sizeof(FORMATETC));
    This->posFmt += cfetch;
  }
  else
  {
    cfetch = 0;
  }
  
  if (pceltFethed)
  {
    *pceltFethed = cfetch;
  }
  
  return hres;
}

/************************************************************************
 * OLEClipbrd_IEnumFORMATETC_Skip (IEnumFORMATETC)
 *
 * Standard enumerator members for IEnumFORMATETC
 */
static HRESULT WINAPI OLEClipbrd_IEnumFORMATETC_Skip(LPENUMFORMATETC iface, ULONG celt)
{
  ICOM_THIS(IEnumFORMATETCImpl,iface);
  TRACE("(%p)->(num=%lu)\n", This, celt);
  
  This->posFmt += celt;
  if (This->posFmt > This->countFmt)
  {
    This->posFmt = This->countFmt;
    return S_FALSE;
  }
  return S_OK;
}

/************************************************************************
 * OLEClipbrd_IEnumFORMATETC_Reset (IEnumFORMATETC)
 *
 * Standard enumerator members for IEnumFORMATETC
 */
static HRESULT WINAPI OLEClipbrd_IEnumFORMATETC_Reset(LPENUMFORMATETC iface)
{
  ICOM_THIS(IEnumFORMATETCImpl,iface);
  TRACE("(%p)->()\n", This);
  
  This->posFmt = 0;
  return S_OK;
}

/************************************************************************
 * OLEClipbrd_IEnumFORMATETC_Clone (IEnumFORMATETC)
 *
 * Standard enumerator members for IEnumFORMATETC
 */
static HRESULT WINAPI OLEClipbrd_IEnumFORMATETC_Clone
  (LPENUMFORMATETC iface, LPENUMFORMATETC* ppenum)
{
  ICOM_THIS(IEnumFORMATETCImpl,iface);
  HRESULT hr = S_OK;
  
  TRACE("(%p)->(ppenum=%p)\n", This, ppenum);

  if ( !ppenum )
    return E_INVALIDARG;

  *ppenum = OLEClipbrd_IEnumFORMATETC_Construct(This->countFmt,
                                                This->pFmt,
                                                This->pUnkDataObj);

  if (FAILED( hr = IEnumFORMATETC_AddRef(*ppenum)))
    return ( hr );
  
  return (*ppenum) ? S_OK : E_OUTOFMEMORY;
}