mozglue/misc/GetKnownFolderPath.cpp

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include "GetKnownFolderPath.h"
   6
   7 namespace mozilla {
   8
   9 UniquePtr<wchar_t, LoadedCoTaskMemFreeDeleter> GetKnownFolderPath(
  10     REFKNOWNFOLDERID folderId) {
  11   static decltype(SHGetKnownFolderPath)* shGetKnownFolderPath = nullptr;
  12   if (!shGetKnownFolderPath) {
  13     // We could go out of our way to `FreeLibrary` on this, decrementing its
  14     // ref count and potentially unloading it. However doing so would be either
  15     // effectively a no-op, or counterproductive. Just let it get cleaned up
  16     // when the process is terminated, because we're going to load it anyway
  17     // elsewhere.
  18     HMODULE shell32Dll = ::LoadLibraryW(L"shell32");
  19     if (!shell32Dll) {
  20       return nullptr;
  21     }
  22     shGetKnownFolderPath = reinterpret_cast<decltype(shGetKnownFolderPath)>(
  23         ::GetProcAddress(shell32Dll, "SHGetKnownFolderPath"));
  24     if (!shGetKnownFolderPath) {
  25       return nullptr;
  26     }
  27   }
  28   PWSTR path = nullptr;
  29   shGetKnownFolderPath(folderId, 0, nullptr, &path);
  30   return UniquePtr<wchar_t, LoadedCoTaskMemFreeDeleter>(path);
  31 }
  32
  33 }  // namespace mozilla