1  // dllmain.cpp : Defines the entry point for the DLL application.
 2  #include "pch.h"
 3  #include "ClassFactory.h"
 4  
 5  HINSTANCE g_hInst = NULL;
 6  long g_cDllRef = 0;
 7  
 8  // {FCDD4EED-41AA-492F-8A84-31A1546226E0}
 9  static const GUID CLSID_SvgPreviewHandler = { 0xfcdd4eed, 0x41aa, 0x492f, { 0x8a, 0x84, 0x31, 0xa1, 0x54, 0x62, 0x26, 0xe0 } };
10  
11  BOOL APIENTRY DllMain(HMODULE hModule,
12                        DWORD ul_reason_for_call,
13                        LPVOID lpReserved)
14  {
15      switch (ul_reason_for_call)
16      {
17      case DLL_PROCESS_ATTACH:
18          g_hInst = hModule;
19          DisableThreadLibraryCalls(hModule);
20          break;
21      case DLL_THREAD_ATTACH:
22      case DLL_THREAD_DETACH:
23      case DLL_PROCESS_DETACH:
24          break;
25      }
26      return TRUE;
27  }
28  
29  //
30  //   FUNCTION: DllGetClassObject
31  //
32  //   PURPOSE: Create the class factory and query to the specific interface.
33  //
34  //   PARAMETERS:
35  //   * rclsid - The CLSID that will associate the correct data and code.
36  //   * riid - A reference to the identifier of the interface that the caller
37  //     is to use to communicate with the class object.
38  //   * ppv - The address of a pointer variable that receives the interface
39  //     pointer requested in riid. Upon successful return, *ppv contains the
40  //     requested interface pointer. If an error occurs, the interface pointer
41  //     is NULL.
42  //
43  STDAPI DllGetClassObject(REFCLSID rclsid, REFIID riid, void** ppv)
44  {
45      HRESULT hr = CLASS_E_CLASSNOTAVAILABLE;
46  
47      if (IsEqualCLSID(CLSID_SvgPreviewHandler, rclsid))
48      {
49          hr = E_OUTOFMEMORY;
50  
51          ClassFactory* pClassFactory = new ClassFactory();
52          if (pClassFactory)
53          {
54              hr = pClassFactory->QueryInterface(riid, ppv);
55              pClassFactory->Release();
56          }
57      }
58  
59      return hr;
60  }
61  
62  //
63  //   FUNCTION: DllCanUnloadNow
64  //
65  //   PURPOSE: Check if we can unload the component from the memory.
66  //
67  //   NOTE: The component can be unloaded from the memory when its reference
68  //   count is zero (i.e. nobody is still using the component).
69  //
70  STDAPI DllCanUnloadNow(void)
71  {
72      return g_cDllRef > 0 ? S_FALSE : S_OK;
73  }