HRESULT FindInterfaceAnywhere(
IGraphBuilder *pGraph,
REFGUID iid,
void **ppUnk)
{
if (!pGraph || !ppUnk) return E_POINTER;
HRESULT hr = E_FAIL;
IEnumFilters *pEnum = 0;
if (FAILED(pGraph->EnumFilters(&pEnum)))
{
return E_FAIL;
}
// Loop through every filter in the graph.
IBaseFilter *pF = 0;
while (S_OK == pEnum->Next(1, &pF, 0))
{
hr = pF->QueryInterface(iid, ppUnk);
if (FAILED(hr))
{
// The filter does not expose the interface, but maybe
// one of its pins does.
hr = FindPinInterface(pF, iid, ppUnk);
}
pF->Release();
if (SUCCEEDED(hr))
{
break;
}
}
pEnum->Release();
return hr;
}
//查找FilterGraph上某一个接口，不管在Filter还是Pin上，找到即返回
BOOL FindInterface(IGraphBuilder* pGraphBuilder, REFGUID iid, void** ppUnk)
{
if(!pGraphBuilder || !ppUnk)
return FALSE;
HRESULT hr = E_FAIL;
IEnumFilters* pEnumFilter = NULL;
if(FAILED(pGraphBuilder->QueryInterface(&pEnumFilter)))
return FALSE;
BOOL bRet = FALSE;
IBaseFilter* pFilter = NULL;
while(S_OK == pEnumFilter->Next(1,&pFilter,NULL))
{
hr = pFilter->QueryInterface(iid,ppUnk);
if(SUCCEEDED(hr))
{
bRet = TRUE;
pFilter->Release();
break;
}
else
{
bRet = FindPinInterface(pFilter,iid,ppUnk);
if(bRet)
{
pFilter->Release();
break;
}
}
pFilter->Release();
}
pEnumFilter->Release();
return FALSE;
}
