iadvsink.cpp

DCOM 上位机和嵌入式系统通信

/*
 * IADVSINK.CPP
 *
 * Implementation of the IAdviseSink interface for the Data User*/

#include "stdafx.h"
#include "CLIENT.h"
#include "iadvsink.h"
#include "iopcdatacallback_imp.h"
#include "iopcshutdown_imp.h"
#include "opc_user.h"

/////////////////////////////////////////////////////////////////////
//
//  Constructor / Destructor
 
CImpIAdviseSink::CImpIAdviseSink( CClientOPCGroup* pParent )
{
  m_dwRef=0;
  m_dwDataChange = 0;
  m_pGroup=pParent;
  return;
}

CImpIAdviseSink::~CImpIAdviseSink(void)
{
  m_pGroup->m_pSink = NULL;
  return;
}

/*
 * CImpIAdviseSink::QueryInterface
 * CImpIAdviseSink::AddRef
 * CImpIAdviseSink::Release
 *
 * Purpose:
 *  IUnknown members for CImpIAdviseSink object.
 */

STDMETHODIMP CImpIAdviseSink::QueryInterface(REFIID riid, LPVOID FAR *ppv)
{
  *ppv=NULL;

  //Any interface on this object is the object pointer.
  if (IsEqualIID(riid, IID_IUnknown) || IsEqualIID(riid, IID_IAdviseSink))
      *ppv=(LPVOID)this;

  if (NULL!=*ppv)
  {
    ((LPUNKNOWN)*ppv)->AddRef();
    return S_OK;
  }

  return E_NOINTERFACE;
}


STDMETHODIMP_(ULONG) CImpIAdviseSink::AddRef(void)
{
  return ++m_dwRef;
}


STDMETHODIMP_(ULONG) CImpIAdviseSink::Release(void)
{
ULONG   cRefT;

  cRefT = --m_dwRef;

  if(0  ==  cRefT)
    delete this;

  return cRefT;
}

/*
 * IAdviseSink::OnDataChange
 *
 * Purpose:
 *  Notifes the advise sink that data changed in a data object.  On
 *  this message you may request a new data rendering and update your
 *  displays as necessary.  Any data sent to this function is owned
 *  by the caller, not by this advise sink!
 *
 *  All Advise Sink methods should be considered asynchronous and therefore
 *  we should attempt no synchronous calls from within them to an EXE
 *  object.  If we do, we'll get RPC_E_CALLREJECTED as shown below.
 *
 * Parameters:
 *  pFE             LPFORMATETC describing format that changed
 *  pSTM            LPSTGMEDIUM providing the medium in which the data
 *                  is provided.
 *
 * Return Value:
 *  None
 */
STDMETHODIMP_(void) CImpIAdviseSink::OnDataChange(LPFORMATETC pFE, LPSTGMEDIUM pSTM)
{
  m_dwDataChange ++;
  if( !(DVASPECT_CONTENT & pFE->dwAspect))
    return;

  if( pSTM==NULL ||pSTM->hGlobal == NULL)
    return;
  if( m_pGroup->m_pIDataObject == NULL) return;

  // for Hot links the data comes with the OnDataChange
  m_pGroup->GetDataFromStorageMedium( pFE, pSTM ) ;

  ReleaseStgMedium(pSTM);
  return;
}