sdk/samples/all in on code/Visual Studio 2010/CppShellExtThumbnailHandler/ClassFactory.cpp

   1 /****************************** Module Header ******************************\
   2 Module Name:  ClassFactory.cpp
   3 Project:      CppShellExtThumbnailHandler
   4 Copyright (c) Microsoft Corporation.
   5
   6 The file implements the class factory for the RecipeThumbnailProvider COM class.
   7
   8 This source is subject to the Microsoft Public License.
   9 See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.
  10 All other rights reserved.
  11
  12 THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
  13 EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
  14 WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
  15 \***************************************************************************/
  16
  17 #include "ClassFactory.h"
  18 #include "RecipeThumbnailProvider.h"
  19 #include <new>
  20
  21
  22 extern long g_cDllRef;
  23
  24
  25 ClassFactory::ClassFactory() : m_cRef(1)
  26 {
  27     InterlockedIncrement(&g_cDllRef);
  28 }
  29
  30 ClassFactory::~ClassFactory()
  31 {
  32     InterlockedDecrement(&g_cDllRef);
  33 }
  34
  35
  36 //
  37 // IUnknown
  38 //
  39
  40 IFACEMETHODIMP ClassFactory::QueryInterface(REFIID riid, void **ppv)
  41 {
  42     HRESULT hr = S_OK;
  43
  44     if (IsEqualIID(IID_IUnknown, riid) ||
  45         IsEqualIID(IID_IClassFactory, riid))
  46     {
  47         *ppv = static_cast<IUnknown *>(this);
  48         AddRef();
  49     }
  50     else
  51     {
  52         hr = E_NOINTERFACE;
  53         *ppv = NULL;
  54     }
  55
  56     return hr;
  57 }
  58
  59 IFACEMETHODIMP_(ULONG) ClassFactory::AddRef()
  60 {
  61     return InterlockedIncrement(&m_cRef);
  62 }
  63
  64 IFACEMETHODIMP_(ULONG) ClassFactory::Release()
  65 {
  66     ULONG cRef = InterlockedDecrement(&m_cRef);
  67     if (0 == cRef)
  68     {
  69         delete this;
  70     }
  71     return cRef;
  72 }
  73
  74
  75 //
  76 // IClassFactory
  77 //
  78
  79 IFACEMETHODIMP ClassFactory::CreateInstance(IUnknown *pUnkOuter, REFIID riid, void **ppv)
  80 {
  81     HRESULT hr = CLASS_E_NOAGGREGATION;
  82
  83     // pUnkOuter is used for aggregation. We do not support it in the sample.
  84     if (pUnkOuter == NULL)
  85     {
  86         hr = E_OUTOFMEMORY;
  87
  88         // Create the COM component.
  89         RecipeThumbnailProvider *pExt = new (std::nothrow) RecipeThumbnailProvider();
  90         if (pExt)
  91         {
  92             // Query the specified interface.
  93             hr = pExt->QueryInterface(riid, ppv);
  94             pExt->Release();
  95         }
  96     }
  97
  98     return hr;
  99 }
 100
 101 IFACEMETHODIMP ClassFactory::LockServer(BOOL fLock)
 102 {
 103     if (fLock)
 104     {
 105         InterlockedIncrement(&g_cDllRef);
 106     }
 107     else
 108     {
 109         InterlockedDecrement(&g_cDllRef);
 110     }
 111     return S_OK;
 112 }