windows-xp/Source/XPSP1/NT/enduser/stuff/hhctrl/unknown.cpp

// Copyright (C) 1996-1997 Microsoft Corporation. All rights reserved.

#include "header.h"
#include "Unknown.H"
#include <stddef.h>

//=--------------------------------------------------------------------------=
// CUnknownObject::CPrivateUnknownObject::m_pMainUnknown
//=--------------------------------------------------------------------------=
// this method is used when we're sitting in the private unknown object,
// and we need to get at the pointer for the main unknown.	basically, it's
// a little better to do this pointer arithmetic than have to store a pointer
// to the parent, etc.

inline CUnknownObject *CUnknownObject::CPrivateUnknownObject::m_pMainUnknown
(
	void
)
{
	return (CUnknownObject *)((LPBYTE)this - offsetof(CUnknownObject, m_UnkPrivate));
}

//=--------------------------------------------------------------------------=
// CUnknownObject::CPrivateUnknownObject::QueryInterface
//=--------------------------------------------------------------------------=
// this is the non-delegating internal QI routine.
//
// Parameters:
//	  REFIID		- [in]	interface they want
//	  void **		- [out] where they want to put the resulting object ptr.
//
// Output:
//	  HRESULT		- S_OK, E_NOINTERFACE

STDMETHODIMP CUnknownObject::CPrivateUnknownObject::QueryInterface(REFIID riid, void **ppvObjOut)
{
	CHECK_POINTER(ppvObjOut);

	// if they're asking for IUnknown, then we have to pass them ourselves.
	// otherwise defer to the inheriting object's InternalQueryInterface
	//
	if (DO_GUIDS_MATCH(riid, IID_IUnknown)) {
		m_cRef++;
		*ppvObjOut = (IUnknown *)this;
		return S_OK;
	} else
		return m_pMainUnknown()->InternalQueryInterface(riid, ppvObjOut);

	// dead code
}

//=--------------------------------------------------------------------------=
// CUnknownObject::CPrivateUnknownObject::AddRef
//=--------------------------------------------------------------------------=
// adds a tick to the current reference count.
//
// Output:
//	  ULONG 	   - the new reference count

ULONG CUnknownObject::CPrivateUnknownObject::AddRef(void)
{
	return ++m_cRef;
}

//=--------------------------------------------------------------------------=
// CUnknownObject::CPrivateUnknownObject::Release
//=--------------------------------------------------------------------------=
// removes a tick from the count, and delets the object if necessary
//
// Output:
//	  ULONG 		- remaining refs

ULONG CUnknownObject::CPrivateUnknownObject::Release (void)
{
	ULONG cRef = --m_cRef;

	if (!m_cRef)
		delete m_pMainUnknown();

	return cRef;
}


//=--------------------------------------------------------------------------=
// CUnknownObject::InternalQueryInterface
//=--------------------------------------------------------------------------=
// objects that are aggregated use this to support additional interfaces.
// they should call this method on their parent so that any of it's interfaces
// are queried.
//
// Parameters:
//	  REFIID		- [in]	interface they want
//	  void **		- [out] where they want to put the resulting object ptr.
//
// Output:
//	  HRESULT		- S_OK, E_NOINTERFACE

HRESULT CUnknownObject::InternalQueryInterface(REFIID riid, void **ppvObjOut)
{
	*ppvObjOut = NULL;

	return E_NOINTERFACE;
}