KOALA.CPP

/* 
 * KOALA.CPP 
 * Koala Object Independent of DLL/EXE Servers, Chapter 5 
 * 
 * Implementation of the CKoala object that works in either 
 * an EXE or DLL as it only implements IUnknown. 
 * 
 * Copyright (c)1993-1995 Microsoft Corporation, All Rights Reserved 
 * 
 * Kraig Brockschmidt, Microsoft 
 * Internet  :  kraigb@microsoft.com 
 * Compuserve:  >INTERNET:kraigb@microsoft.com 
 */ 
 
 
#include "koala.h" 
 
 
/* 
 * CKoala::CKoala 
 * CKoala::~CKoala 
 * 
 * Parameters (Constructor): 
 *  pUnkOuter       LPUNKNOWN of a controlling unknown. 
 *  pfnDestroy      PFNDESTROYED to call when an object 
 *                  is destroyed. 
 */ 
 
CKoala::CKoala(LPUNKNOWN pUnkOuter, PFNDESTROYED pfnDestroy) 
    { 
    m_cRef=0; 
    m_pUnkOuter=pUnkOuter; 
    m_pfnDestroy=pfnDestroy; 
    return; 
    } 
 
CKoala::~CKoala(void) 
    { 
    return; 
    } 
 
 
 
/* 
 * CKoala::Init 
 * 
 * Purpose: 
 *  Performs any intiailization of a CKoala that's prone to failure 
 *  that we also use internally before exposing the object outside. 
 * 
 * Parameters: 
 *  None 
 * 
 * Return Value: 
 *  BOOL            TRUE if the function is successful, 
 *                  FALSE otherwise. 
 */ 
 
BOOL CKoala::Init(void) 
    { 
    //Nothing to do. 
    return TRUE; 
    } 
 
 
 
 
/* 
 * CKoala::QueryInterface 
 * CKoala::AddRef 
 * CKoala::Release 
 * 
 * Purpose: 
 *  IUnknown members for CKoala object. 
 */ 
 
STDMETHODIMP CKoala::QueryInterface(REFIID riid, PPVOID ppv) 
    { 
    *ppv=NULL; 
 
    /* 
     * The only calls for IUnknown are either in a nonaggregated 
     * case or when created in an aggregation, so in either case 
     * always return our IUnknown for IID_IUnknown. 
     */ 
    if (IID_IUnknown==riid) 
        *ppv=this; 
 
    if (NULL!=*ppv) 
        { 
        ((LPUNKNOWN)*ppv)->AddRef(); 
        return NOERROR; 
        } 
 
    return ResultFromScode(E_NOINTERFACE); 
    } 
 
 
STDMETHODIMP_(ULONG) CKoala::AddRef(void) 
    { 
    return ++m_cRef; 
    } 
 
 
STDMETHODIMP_(ULONG) CKoala::Release(void) 
    { 
    if (0L!=--m_cRef) 
        return m_cRef; 
 
    /* 
     * Tell the housing that an object is going away so it can 
     * shut down if appropriate. 
     */ 
    if (NULL!=m_pfnDestroy) 
        (*m_pfnDestroy)(); 
 
    delete this; 
    return 0; 
    }