Understanding The COM Single-Threaded Apartment Part 1

#include "ExeObj02.h"
#include <stdio.h>






CExeObj02::CExeObj02()
{
  ::CoCreateInstance
  (
    CLSID_ExeObj01,     //Class identifier (CLSID) of the object
    NULL, //Pointer to controlling IUnknown
    CLSCTX_LOCAL_SERVER,  //Context for running executable code
    IID_IExeObj01,         //Reference to the identifier of the interface
    (LPVOID*)&m_pIExeObj01         //Address of output variable that receives 
                           // the interface pointer requested in riid
  );
}





CExeObj02::~CExeObj02()
{
  if (m_pIExeObj01)
  {
    m_pIExeObj01 -> Release();
	m_pIExeObj01 = NULL;
  }
}





STDMETHODIMP CExeObj02::QueryInterface(REFIID riid, void** ppvObject)
{
  if (riid == IID_IUnknown || riid == IID_IExeObj02)
  {
	*ppvObject = (IExeObj02*)this;
	((CReferenceCountedObject*)this) -> AddRef();
	return S_OK;
  }
  
  return E_NOINTERFACE;
}





// IUnknown method.
STDMETHODIMP_(ULONG) CExeObj02::AddRef()
{
  return CReferenceCountedObject::AddRef();
}





// IUnknown method.
STDMETHODIMP_(ULONG) CExeObj02::Release()
{
  return CReferenceCountedObject::Release();
}





STDMETHODIMP CExeObj02::TestMethod1()
{
  TCHAR szMessage[256];

  sprintf (szMessage, "0x%X", GetCurrentThreadId());

  ::MessageBox(NULL, szMessage, "CExeObj02::TestMethod1()", MB_OK);

  return m_pIExeObj01 -> TestMethod1();
}





CExeObj02_Factory::CExeObj02_Factory()
{
}





CExeObj02_Factory::~CExeObj02_Factory()
{
}





// IUnknown method. Overridde QueryInterface() method.
STDMETHODIMP CExeObj02_Factory::QueryInterface(REFIID riid, void** ppvObject)
{
  if (riid == IID_IUnknown)
  {
    CReferenceCountedObject* pCReferenceCountedObject = (CReferenceCountedObject*)this;

	*ppvObject = (IUnknown*)pCReferenceCountedObject;
	((CReferenceCountedObject*)this) -> AddRef();
	return S_OK;
  }

  if (riid == IID_IClassFactory)
  {
    *ppvObject = (IClassFactory*)this;
	((CReferenceCountedObject*)this) -> AddRef();
	return S_OK;
  }

  *ppvObject = NULL;
  
  return E_NOINTERFACE;
}





// IUnknown method.
STDMETHODIMP_(ULONG) CExeObj02_Factory::AddRef()
{
  return CClassFactory::AddRef();
}





// IUnknown method.
STDMETHODIMP_(ULONG) CExeObj02_Factory::Release()
{
  return CClassFactory::Release();
}





// IClassFactory method.
STDMETHODIMP CExeObj02_Factory::CreateInstance
(
  IUnknown __RPC_FAR *pUnkOuter,
  REFIID riid,
  void __RPC_FAR *__RPC_FAR *ppvObject
)
{
  CExeObj02*	pCExeObj02 = NULL;

  // Initialise the receiver.
  *ppvObject = NULL;

  if (pUnkOuter != NULL)
  {
	return CLASS_E_NOAGGREGATION;
  }

  // Create an instance of the component.
  pCExeObj02 = new CExeObj02;

  if (pCExeObj02 == NULL)
  {
	return E_OUTOFMEMORY;
  }

  pCExeObj02 -> QueryInterface (riid, ppvObject);

  pCExeObj02 -> Release();

  return S_OK;
}





// IClassFactory method.
STDMETHODIMP CExeObj02_Factory::LockServer
(
  BOOL fLock
)
{
  return CClassFactory::LockServer(fLock);
}