//
// NonDelegatingQueryInterface
//
// This function is overwritten to expose IMediaPosition and IMediaSelection
// Note that only one output stream can be allowed to expose this to avoid
// conflicts, the other pins will just return E_NOINTERFACE and therefore
// appear as non seekable streams. We have a LONG value that if exchanged to
// produce a TRUE means that we have the honor. If it exchanges to FALSE then
// someone is already in. If we do get it and error occurs then we reset it
// to TRUE so someone else can get it.
//
STDMETHODIMP
CTeeOutputPin::NonDelegatingQueryInterface(REFIID riid, void **ppv)
{
CheckPointer(ppv,E_POINTER);
ASSERT(ppv);
*ppv = NULL;
HRESULT hr = NOERROR;
// See what interface the caller is interested in.
if(riid == IID_IMediaPosition || riid == IID_IMediaSeeking)
{
if(m_pPosition)
{
if(m_bHoldsSeek == FALSE)
return E_NOINTERFACE;
return m_pPosition->QueryInterface(riid, ppv);
}
}
else
{
return CBaseOutputPin::NonDelegatingQueryInterface(riid, ppv);
}
CAutoLock lock_it(m_pLock);
ASSERT(m_pPosition == NULL);
IUnknown *pMediaPosition = NULL;
// Try to create a seeking implementation
if(InterlockedExchange(&m_pTee->m_lCanSeek, FALSE) == FALSE)
return E_NOINTERFACE;
// Create implementation of this dynamically as sometimes we may never
// try and seek. The helper object implements IMediaPosition and also
// the IMediaSelection control interface and simply takes the calls
// normally from the downstream filter and passes them upstream
hr = CreatePosPassThru(GetOwner(),
FALSE,
(IPin *)&m_pTee->m_Input,
&pMediaPosition);
if(pMediaPosition == NULL)
{
InterlockedExchange(&m_pTee->m_lCanSeek, TRUE);
return E_OUTOFMEMORY;
}
if(FAILED(hr))
{
InterlockedExchange(&m_pTee->m_lCanSeek, TRUE);
pMediaPosition->Release();
return hr;
}
m_pPosition = pMediaPosition;
m_bHoldsSeek = TRUE;
return NonDelegatingQueryInterface(riid, ppv);
} // NonDelegatingQueryInterface
HRESULT VMRSurfaceAllocator::QueryInterface( REFIID iid, PVOID *pvInterface )
{
return NonDelegatingQueryInterface( iid, pvInterface );
}
