Added checks if TypeLib is registered on system or for current user. If TyleLib is not already registered, then we assume that we can silence error 0x8002801c (TYPE_E_REGISTRYACCESS).

Author: end2endzone

src/shellextension/TypeLibHelper.cpp

@@ -4,7 +4,49 @@
 #include <strsafe.h> // for StringCchPrintf()
 
 using namespace ATL;
-extern HRESULT GetHKCRRegistryKeyAndValue(PCWSTR pszSubKey, PCWSTR pszValueName, PWSTR pszData, DWORD cbData);	// from Reg.cpp
+
+//
+//   FUNCTION: GetHKEYRegistryKeyAndValue
+//
+//   PURPOSE: The function opens the given HKEY (HKCR, HKCU, etc) registry key and gets the data for the 
+//   specified registry value name.
+//
+//   PARAMETERS:
+//   * hRootKey - One of the reserved root key handles. For example:
+//     HKEY_CLASSES_ROOT, HKEY_CURRENT_USER, HKEY_LOCAL_MACHINE, HKEY_USERS or 
+//   * pszSubKey - specifies the registry key under HKCR. If the key does not 
+//     exist, the function returns an error.
+//   * pszValueName - specifies the registry value to be retrieved. If 
+//     pszValueName is NULL, the function will get the default value.
+//   * pszData - a pointer to a buffer that receives the value's string data.
+//   * cbData - specifies the size of the buffer in bytes.
+//
+//   RETURN VALUE:
+//   If the function succeeds, it returns S_OK. Otherwise, it returns an 
+//   HRESULT error code. For example, if the specified registry key does not 
+//   exist or the data for the specified value name was not set, the function 
+//   returns COR_E_FILENOTFOUND (0x80070002).
+// 
+HRESULT GetHKEYRegistryKeyAndValue(HKEY hRootKey, PCWSTR pszSubKey, PCWSTR pszValueName, PWSTR pszData, DWORD cbData)
+{
+  HRESULT hr;
+  HKEY hKey = NULL;
+
+  // Try to open the specified registry key. 
+  hr = HRESULT_FROM_WIN32(RegOpenKeyEx(hRootKey, pszSubKey, 0,
+                          KEY_READ, &hKey));
+
+  if (SUCCEEDED(hr))
+  {
+    // Get the data for the specified value name.
+    hr = HRESULT_FROM_WIN32(RegQueryValueEx(hKey, pszValueName, NULL,
+                            NULL, reinterpret_cast<LPBYTE>(pszData), &cbData));
+
+    RegCloseKey(hKey);
+  }
+
+  return hr;
+}
 
 HRESULT GetTypeLibGuid(_In_ HINSTANCE hInstTypeLib, _In_opt_z_ LPCOLESTR lpszIndex, GUID& guid)
 {
@@ -53,7 +95,7 @@ HRESULT IsTypeLibRegisteredOnSystem(const GUID& guid, PCWSTR szVersion)
   return hr;
 }
 
-HRESULT IsTypeLibRegisteredOnSystem(_In_ LPTLIBATTR pTLibAttr)
+HRESULT IsTypeLibRegisteredUnderKey(HKEY hRootKey, _In_ const LPTLIBATTR pTLibAttr)
 {
   if (NULL == pTLibAttr)
     return E_INVALIDARG;
@@ -84,15 +126,15 @@ HRESULT IsTypeLibRegisteredOnSystem(_In_ LPTLIBATTR pTLibAttr)
     return HRESULT_FROM_WIN32(ERROR_INVALID_FLAGS);
   };
 
-  // Check for the "HKCR\TypeLib\{guid}\{version}" key.
+  // Check for the "HKEY_CLASSES_ROOT\TypeLib\{guid}\{version}" key.
   wchar_t szSubkey[MAX_PATH];
   hr = StringCchPrintf(szSubkey, ARRAYSIZE(szSubkey), L"TypeLib\\%s\\%s", szGUID, szVersion);
   if (FAILED(hr))
     return hr;
 
   // Get the TypeLib name
   wchar_t szTypeLibName[MAX_PATH];
-  hr = GetHKCRRegistryKeyAndValue(szSubkey, nullptr, szTypeLibName, sizeof(szTypeLibName));
+  hr = GetHKEYRegistryKeyAndValue(hRootKey, szSubkey, nullptr, szTypeLibName, sizeof(szTypeLibName));
   if (FAILED(hr))
   {
     if (hr == HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND))
@@ -104,14 +146,14 @@ HRESULT IsTypeLibRegisteredOnSystem(_In_ LPTLIBATTR pTLibAttr)
   if (szTypeLibName[0] == L'\0')
     return S_FALSE;
 
-  // Check for the "HKCR\TypeLib\{guid}\{version}\0\{syskind}" key.
+  // Check for the "HKEY_CLASSES_ROOT\TypeLib\{guid}\{version}\0\{syskind}" key.
   hr = StringCchPrintf(szSubkey, ARRAYSIZE(szSubkey), L"TypeLib\\%s\\%s\\0\\%s", szGUID, szVersion, szSysKind);
   if (FAILED(hr))
     return hr;
 
   // Get the TypeLib dll path
   wchar_t szDllPath[MAX_PATH];
-  hr = GetHKCRRegistryKeyAndValue(szSubkey, nullptr, szDllPath, sizeof(szDllPath));
+  hr = GetHKEYRegistryKeyAndValue(hRootKey, szSubkey, nullptr, szDllPath, sizeof(szDllPath));
   if (FAILED(hr))
   {
     if (hr == HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND))
@@ -138,4 +180,16 @@ HRESULT IsTypeLibRegisteredOnSystem(_In_ LPTLIBATTR pTLibAttr)
   //	return S_FALSE;
 
   return S_OK;
-}
+}
+
+HRESULT IsTypeLibRegisteredOnSystem(_In_ const LPTLIBATTR pTLibAttr)
+{
+  HRESULT hr = IsTypeLibRegisteredUnderKey(HKEY_CLASSES_ROOT, pTLibAttr);
+  return hr;
+}
+
+HRESULT IsTypeLibRegisteredForCurrentUser(_In_ const LPTLIBATTR pTLibAttr)
+{
+  HRESULT hr = IsTypeLibRegisteredUnderKey(HKEY_CURRENT_USER, pTLibAttr);
+  return hr;
+}

src/shellextension/TypeLibHelper.h

@@ -47,4 +47,18 @@ HRESULT IsTypeLibRegisteredOnSystem(const GUID& guid, PCWSTR szVersion);
 /// </remarks>
 /// <param name="pTLibAttr">A pointer to the typelib's attributes.</param>
 /// <returns>Returns S_OK if the typelib is registered on system. Returns S_FALSE if the typelib is not registered on system. Returns an HRESULT matching an error code otherwise.</returns>
-HRESULT IsTypeLibRegisteredOnSystem(_In_ LPTLIBATTR pTLibAttr);
+HRESULT IsTypeLibRegisteredOnSystem(_In_ const LPTLIBATTR pTLibAttr);
+
+/// <summary>
+/// Check if the given typelib is registered for the current user.
+/// </summary>
+/// <remarks>
+/// The following registry keys and values are present for a registered typelib:
+///   [HKEY_CURRENT_USER\TypeLib\{guid}\{version}]
+///   @ = "MyClassNameLib"
+///   [HKEY_CURRENT_USER\TypeLib\{guid}\{version}\0\win64]
+///   @ = "Z:\\path\\to\\current\\file.dll"
+/// </remarks>
+/// <param name="pTLibAttr">A pointer to the typelib's attributes.</param>
+/// <returns>Returns S_OK if the typelib is registered on system. Returns S_FALSE if the typelib is not registered on system. Returns an HRESULT matching an error code otherwise.</returns>
+HRESULT IsTypeLibRegisteredForCurrentUser(_In_ const LPTLIBATTR pTLibAttr);

src/shellextension/dllmain.cpp

@@ -143,24 +143,36 @@ STDAPI DllUnregisterServer(void)
     // See issue #148 for details.
     // Is this failure because the TypeLib is not registered?
 
+    HRESULT hr2 = S_OK;
+
     // Get typelib attributes
     TLIBATTR sTLibAttr;
     ZeroMemory(&sTLibAttr, sizeof(TLIBATTR));
-    if (FAILED(GetTypeLibAttribute(_AtlComModule.m_hInstTypeLib, 0, &sTLibAttr)))
+    hr2 = GetTypeLibAttribute(_AtlComModule.m_hInstTypeLib, 0, &sTLibAttr);
+    if (FAILED(hr2))
       return hr; // return original error
 
-    // Silence the original error only if the TypeLib is not registered on system.
-    HRESULT hr2 = IsTypeLibRegisteredOnSystem(&sTLibAttr);
-    if (SUCCEEDED(hr2) && hr2 == S_FALSE)
-    {
-      // We could assume the error is because the typelib is not registered.
-      // To be certain, we should register the typelib and retry the unregistration:
-      //    _AtlModule.DllRegisterServer(); // don't care about the actual result
-      //    hr = _AtlModule.DllUnregisterServer();
-      // but that could mess up the system if another software is listening for new typelib registrations events.
-      // So we just overrides the original result.
-      return S_OK;
-    }
+    // Check if typelib is registered on system.
+    hr2 = IsTypeLibRegisteredOnSystem(&sTLibAttr);
+    if (FAILED(hr2))
+      return hr; // We don't know if typelib is registered or not. Return original error.
+    if (hr2 == S_OK)
+      return hr; // Yes, the typelib is registered, hr is a legit error. 
+
+    // Check if typelib is registered for current user.
+    hr2 = IsTypeLibRegisteredForCurrentUser(&sTLibAttr);
+    if (FAILED(hr2))
+      return hr; // We don't know if typelib is registered or not. Return original error.
+    if (hr2 == S_OK)
+      return hr; // Yes, the typelib is registered, hr is a legit error. 
+
+    // At this point, assume error 0x8002801c (TYPE_E_REGISTRYACCESS) is because the typelib is not registered.
+    // To be certain, we should register the typelib and retry the unregistration:
+    //    _AtlModule.DllRegisterServer(); // don't care about the actual result
+    //    hr = _AtlModule.DllUnregisterServer();
+    // but that could mess up the system if another software is listening for new typelib registrations events.
+    // So we just silence the original error.
+    return S_OK;
   }
 
   if (SUCCEEDED(hr))