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265 lines
7.4 KiB
C++
265 lines
7.4 KiB
C++
//------------------------------------------------------------------------------
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// File: ComBase.cpp
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//
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// Desc: DirectShow base classes - implements class hierarchy for creating
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// COM objects.
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//
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// Copyright (c) 1992-2001 Microsoft Corporation. All rights reserved.
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//------------------------------------------------------------------------------
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#include <streams.h>
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#pragma warning( disable : 4514 ) // Disable warnings re unused inline functions
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/* Define the static member variable */
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LONG CBaseObject::m_cObjects = 0;
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/* Constructor */
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CBaseObject::CBaseObject(__in_opt LPCTSTR pName)
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{
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/* Increment the number of active objects */
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InterlockedIncrement(&m_cObjects);
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#ifdef DEBUG
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#ifdef UNICODE
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m_dwCookie = DbgRegisterObjectCreation(0, pName);
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#else
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m_dwCookie = DbgRegisterObjectCreation(pName, 0);
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#endif
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#endif
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}
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#ifdef UNICODE
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CBaseObject::CBaseObject(const char *pName)
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{
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/* Increment the number of active objects */
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InterlockedIncrement(&m_cObjects);
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#ifdef DEBUG
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m_dwCookie = DbgRegisterObjectCreation(pName, 0);
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#endif
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}
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#endif
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HINSTANCE hlibOLEAut32;
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/* Destructor */
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CBaseObject::~CBaseObject()
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{
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/* Decrement the number of objects active */
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if (InterlockedDecrement(&m_cObjects) == 0) {
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if (hlibOLEAut32) {
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FreeLibrary(hlibOLEAut32);
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hlibOLEAut32 = 0;
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}
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};
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#ifdef DEBUG
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DbgRegisterObjectDestruction(m_dwCookie);
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#endif
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}
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static const TCHAR szOle32Aut[] = TEXT("OleAut32.dll");
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HINSTANCE LoadOLEAut32()
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{
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if (hlibOLEAut32 == 0) {
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hlibOLEAut32 = LoadLibrary(szOle32Aut);
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}
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return hlibOLEAut32;
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}
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/* Constructor */
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// We know we use "this" in the initialization list, we also know we don't modify *phr.
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#pragma warning( disable : 4355 4100 )
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CUnknown::CUnknown(__in_opt LPCTSTR pName, __in_opt LPUNKNOWN pUnk)
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: CBaseObject(pName)
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/* Start the object with a reference count of zero - when the */
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/* object is queried for it's first interface this may be */
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/* incremented depending on whether or not this object is */
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/* currently being aggregated upon */
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, m_cRef(0)
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/* Set our pointer to our IUnknown interface. */
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/* If we have an outer, use its, otherwise use ours. */
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/* This pointer effectivly points to the owner of */
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/* this object and can be accessed by the GetOwner() method. */
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, m_pUnknown( pUnk != 0 ? pUnk : reinterpret_cast<LPUNKNOWN>( static_cast<PNDUNKNOWN>(this) ) )
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/* Why the double cast? Well, the inner cast is a type-safe cast */
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/* to pointer to a type from which we inherit. The second is */
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/* type-unsafe but works because INonDelegatingUnknown "behaves */
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/* like" IUnknown. (Only the names on the methods change.) */
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{
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// Everything we need to do has been done in the initializer list
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}
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// This does the same as above except it has a useless HRESULT argument
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// use the previous constructor, this is just left for compatibility...
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CUnknown::CUnknown(__in_opt LPCTSTR pName, __in_opt LPUNKNOWN pUnk, __inout_opt HRESULT *phr) :
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CBaseObject(pName),
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m_cRef(0),
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m_pUnknown( pUnk != 0 ? pUnk : reinterpret_cast<LPUNKNOWN>( static_cast<PNDUNKNOWN>(this) ) )
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{
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}
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#ifdef UNICODE
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CUnknown::CUnknown(__in_opt LPCSTR pName, __in_opt LPUNKNOWN pUnk)
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: CBaseObject(pName), m_cRef(0),
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m_pUnknown( pUnk != 0 ? pUnk : reinterpret_cast<LPUNKNOWN>( static_cast<PNDUNKNOWN>(this) ) )
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{ }
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CUnknown::CUnknown(__in_opt LPCSTR pName, __in_opt LPUNKNOWN pUnk, __inout_opt HRESULT *phr) :
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CBaseObject(pName), m_cRef(0),
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m_pUnknown( pUnk != 0 ? pUnk : reinterpret_cast<LPUNKNOWN>( static_cast<PNDUNKNOWN>(this) ) )
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{ }
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#endif
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#pragma warning( default : 4355 4100 )
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/* QueryInterface */
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STDMETHODIMP CUnknown::NonDelegatingQueryInterface(REFIID riid, __deref_out void ** ppv)
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{
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CheckPointer(ppv,E_POINTER);
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ValidateReadWritePtr(ppv,sizeof(PVOID));
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/* We know only about IUnknown */
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if (riid == IID_IUnknown) {
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GetInterface((LPUNKNOWN) (PNDUNKNOWN) this, ppv);
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return NOERROR;
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} else {
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*ppv = NULL;
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return E_NOINTERFACE;
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}
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}
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/* We have to ensure that we DON'T use a max macro, since these will typically */
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/* lead to one of the parameters being evaluated twice. Since we are worried */
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/* about concurrency, we can't afford to access the m_cRef twice since we can't */
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/* afford to run the risk that its value having changed between accesses. */
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template<class T> inline static T ourmax( const T & a, const T & b )
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{
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return a > b ? a : b;
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}
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/* AddRef */
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STDMETHODIMP_(ULONG) CUnknown::NonDelegatingAddRef()
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{
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LONG lRef = InterlockedIncrement( &m_cRef );
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ASSERT(lRef > 0);
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DbgLog((LOG_MEMORY,3,TEXT(" Obj %d ref++ = %d"),
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m_dwCookie, m_cRef));
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return ourmax(ULONG(m_cRef), 1ul);
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}
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/* Release */
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STDMETHODIMP_(ULONG) CUnknown::NonDelegatingRelease()
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{
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/* If the reference count drops to zero delete ourselves */
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LONG lRef = InterlockedDecrement( &m_cRef );
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ASSERT(lRef >= 0);
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DbgLog((LOG_MEMORY,3,TEXT(" Object %d ref-- = %d"),
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m_dwCookie, m_cRef));
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if (lRef == 0) {
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// COM rules say we must protect against re-entrancy.
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// If we are an aggregator and we hold our own interfaces
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// on the aggregatee, the QI for these interfaces will
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// addref ourselves. So after doing the QI we must release
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// a ref count on ourselves. Then, before releasing the
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// private interface, we must addref ourselves. When we do
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// this from the destructor here it will result in the ref
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// count going to 1 and then back to 0 causing us to
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// re-enter the destructor. Hence we add an extra refcount here
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// once we know we will delete the object.
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// for an example aggregator see filgraph\distrib.cpp.
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m_cRef++;
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delete this;
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return ULONG(0);
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} else {
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// Don't touch m_cRef again even in this leg as the object
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// may have just been released on another thread too
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return ourmax(ULONG(lRef), 1ul);
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}
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}
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/* Return an interface pointer to a requesting client
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performing a thread safe AddRef as necessary */
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STDAPI GetInterface(LPUNKNOWN pUnk, __out void **ppv)
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{
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CheckPointer(ppv, E_POINTER);
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*ppv = pUnk;
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pUnk->AddRef();
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return NOERROR;
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}
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/* Compares two interfaces and returns TRUE if they are on the same object */
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BOOL WINAPI IsEqualObject(IUnknown *pFirst, IUnknown *pSecond)
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{
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/* Different objects can't have the same interface pointer for
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any interface
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*/
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if (pFirst == pSecond) {
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return TRUE;
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}
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/* OK - do it the hard way - check if they have the same
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IUnknown pointers - a single object can only have one of these
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*/
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LPUNKNOWN pUnknown1; // Retrieve the IUnknown interface
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LPUNKNOWN pUnknown2; // Retrieve the other IUnknown interface
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HRESULT hr; // General OLE return code
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ASSERT(pFirst);
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ASSERT(pSecond);
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/* See if the IUnknown pointers match */
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hr = pFirst->QueryInterface(IID_IUnknown,(void **) &pUnknown1);
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if (FAILED(hr)) {
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return FALSE;
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}
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ASSERT(pUnknown1);
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/* Release the extra interface we hold */
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pUnknown1->Release();
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hr = pSecond->QueryInterface(IID_IUnknown,(void **) &pUnknown2);
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if (FAILED(hr)) {
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return FALSE;
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}
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ASSERT(pUnknown2);
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/* Release the extra interface we hold */
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pUnknown2->Release();
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return (pUnknown1 == pUnknown2);
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}
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