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unknown.cpp
Package: shell.rar　[view]
Upload User: xhy777
Upload Date: 2007-02-14
Package Size: 24088k
Code Size: 4k
Category:

Windows Kernel

Development Platform:

Visual C++

unknown.cpp：Code Content
  1. /*----------------------------------------------------------------------------
  2. / Title;
  3. /   unknown.cpp
  4. /
  5. / Authors;
  6. /   David De Vorchik (daviddv)
  7. /
  8. / Notes;
  9. /   Helper functions for handling IUnknown
  10. /----------------------------------------------------------------------------*/
  11. #include "pch.h"
  12. #include "cfdefs.h"
  13. #pragma hdrstop
  16. /*-----------------------------------------------------------------------------
  17. / CUnknown
  18. /   Helper functions to aid the implementation of IUnknown within objects,
  19. /   handles not only AddRef and Release, but also QueryInterface.
  20. /----------------------------------------------------------------------------*/
  22. LONG g_cRefCount = 0;          // global reference count
  24. CUnknown::CUnknown() :
  25.     m_cRefCount(1)
  26. {
  27.     InterlockedIncrement(&g_cRefCount);
  28. }
  30. CUnknown::~CUnknown()
  31. {
  32.     InterlockedDecrement(&g_cRefCount);
  33. }
  35. STDMETHODIMP CUnknown::HandleQueryInterface(REFIID riid, LPVOID* ppvObject, LPINTERFACES aInterfaces, int cif)
  36. {
  37.     HRESULT hr = S_OK;
  38.     int i;
  40.     TraceAssert(ppvObject);
  41.     TraceAssert(aInterfaces);
  42.     TraceAssert(cif);
  44.     if ( !ppvObject )
  45.         ExitGracefully(hr, E_INVALIDARG, "Bailing because ppvObject == NULL");
  47.     *ppvObject = NULL;                                              // no interface yet
  49.     for ( i = 0; i != cif; i++ )
  50.     {
  51.         if ( IsEqualIID(riid, *aInterfaces[i].piid) || IsEqualIID(riid, IID_IUnknown) )
  52.         {
  53.             *ppvObject = aInterfaces[i].pvObject;
  54.             goto exit_gracefully;
  55.         }
  56.     }
  58.     hr = E_NOINTERFACE;         // failed.
  60. exit_gracefully:
  62.     if ( SUCCEEDED(hr) )
  63.         ((LPUNKNOWN)*ppvObject)->AddRef();
  65.     return hr;
  66. }
  68. STDMETHODIMP_(ULONG) CUnknown::HandleAddRef()
  69. {
  70.     return InterlockedIncrement(&m_cRefCount);
  72. }
  74. STDMETHODIMP_(ULONG) CUnknown::HandleRelease()
  75. {
  76.     ULONG cRefCount; 
  78.     cRefCount = InterlockedDecrement(&m_cRefCount);
  79.         
  80.     if ( cRefCount )
  81.         return cRefCount;
  83.     delete this;    
  84.     return 0;
  85. }
  88. /*-----------------------------------------------------------------------------
  89. / Static class factory - from browseui
  90. /----------------------------------------------------------------------------*/
  92. STDMETHODIMP CClassFactory::QueryInterface(REFIID riid, void **ppvObj)
  93. {
  94.     if (IsEqualIID(riid, IID_IClassFactory) || IsEqualIID(riid, IID_IUnknown))
  95.     {
  96.         *ppvObj = (void *)GET_ICLASSFACTORY(this);
  97.         InterlockedIncrement(&g_cRefCount);
  98.         return NOERROR;
  99.     }
  101.     *ppvObj = NULL;
  102.     return E_NOINTERFACE;
  103. }
  105. STDMETHODIMP_(ULONG) CClassFactory::AddRef()
  106. {
  107.     InterlockedIncrement(&g_cRefCount);
  108.     return 2;
  109. }
  111. STDMETHODIMP_(ULONG) CClassFactory::Release()
  112. {
  113.     InterlockedDecrement(&g_cRefCount);
  114.     return 1;
  115. }
  117. STDMETHODIMP CClassFactory::CreateInstance(IUnknown *punkOuter, REFIID riid, void **ppv)
  118. {
  119.     *ppv = NULL;
  121.     if (punkOuter && !IsEqualIID(riid, IID_IUnknown))
  122.     {
  123.         // It is technically illegal to aggregate an object and request
  124.         // any interface other than IUnknown. Enforce this.
  125.         //
  126.         return CLASS_E_NOAGGREGATION;
  127.     }
  128.     else
  129.     {
  130.         LPOBJECTINFO pthisobj = (LPOBJECTINFO)this;
  132.         if ( punkOuter )
  133.             return CLASS_E_NOAGGREGATION;
  135.         IUnknown *punk;
  136.         HRESULT hres = pthisobj->pfnCreateInstance(punkOuter, &punk, pthisobj);
  137.         if (SUCCEEDED(hres))
  138.         {
  139.             hres = punk->QueryInterface(riid, ppv);
  140.             punk->Release();
  141.         }
  143.         return hres;
  144.     }
  145. }
  147. STDMETHODIMP CClassFactory::LockServer(BOOL fLock)
  148. {
  149.     if (fLock)
  150.         InterlockedIncrement(&g_cRefCount);
  151.     else
  152.         InterlockedDecrement(&g_cRefCount);
  154.     return S_OK;
  155. }