CoCarClassFactory

// -----------------CoCarClassFactory.h
#ifndef _COCARCLASSFACTORY_H
#define _COCARCLASSFACTORY_H

#include <Windows.h>
class CoCarClassFactory :
	public IClassFactory
{
public:
	CoCarClassFactory();
	virtual ~CoCarClassFactory();

	// IUnknown
	STDMETHODIMP QueryInterface(REFIID riid, void** ppv);
	STDMETHODIMP_(ULONG) AddRef();
	STDMETHODIMP_(ULONG) Release();

	// IClassFactory
	STDMETHODIMP LockServer(bool fLock);
	STDMETHODIMP CreateInstance(LPUNKNOWN pUnkOuter,
		REFIID riid, void** ppv);
private:
	ULONG m_refCount;
};

#endif


// ------------------CoCarClassFactory.cpp
#include "CoCarClassFactory.h"
#include "CoCar.h"

extern ULONG g_LockCount;
extern ULONG g_objCount;

// Constructor
CoCarClassFactory::CoCarClassFactory()
{
	m_refCount = 0;
	g_objCount++;
}
// Destructor
CoCarClassFactory::~CoCarClassFactory()
{
	g_objCount--;
}

// The class factory's IUnknown implementation.
STDMETHODIMP_(ULONG) CoCarClassFactory::AddRef()
{
	return ++m_refCount;
}
STDMETHODIMP_(ULONG) CoCarClassFactory::Release()
{
	if (--m_refCount == 0)
	{
		delete this;
		return 0;
	}
	return m_refCount;
}
STDMETHODIMP CoCarClassFactory::QueryInterface(REFIID riid, void** ppv)
{
	// Which aspect of me do they want?
	if (riid == IID_IUnknown)
	{
		*ppv = (IUnknown*)this;
	}
	else if (riid == IID_IClassFactory)
	{
		*ppv = (IClassFactory*)this;
	}
	else
	{
		*ppv = NULL;
		return E_NOINTERFACE;
	}
	((IUnknown*)(*ppv))->AddRef();
	return S_OK;
}

// The class factory's IClassFactory implementation
STDMETHODIMP CoCarClassFactory::CreateInstance(LPUNKNOWN pUnkOuter,
		REFIID riid, void** ppv)
{
	if (pUnkOuter != NULL)
		return CLASS_E_NOAGGREGATION;

	CoCar* pCarObj = NULL;
	HRESULT hr;

	pCarObj = new CoCar;
	hr = pCarObj->QueryInterface(riid, ppv);
	if (FAILED(hr))
		delete pCarObj;
	return hr;
}
STDMETHODIMP CoCarClassFactory::LockServer(bool fLock)
{
	if (fLock)
		++g_LockCount;
	else
		--g_LockCount;
	return S_OK;
}