1 files changed, 33 insertions, 0 deletions
diff --git a/mozglue/misc/GetKnownFolderPath.cpp b/mozglue/misc/GetKnownFolderPath.cpp
new file mode 100644
index 0000000000..676a1c8056
--- /dev/null
+++ b/mozglue/misc/GetKnownFolderPath.cpp
@@ -0,0 +1,33 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "GetKnownFolderPath.h"
+
+namespace mozilla {
+
+UniquePtr<wchar_t, LoadedCoTaskMemFreeDeleter> GetKnownFolderPath(
+    REFKNOWNFOLDERID folderId) {
+  static decltype(SHGetKnownFolderPath)* shGetKnownFolderPath = nullptr;
+  if (!shGetKnownFolderPath) {
+    // We could go out of our way to `FreeLibrary` on this, decrementing its
+    // ref count and potentially unloading it. However doing so would be either
+    // effectively a no-op, or counterproductive. Just let it get cleaned up
+    // when the process is terminated, because we're going to load it anyway
+    // elsewhere.
+    HMODULE shell32Dll = ::LoadLibraryW(L"shell32");
+    if (!shell32Dll) {
+      return nullptr;
+    }
+    shGetKnownFolderPath = reinterpret_cast<decltype(shGetKnownFolderPath)>(
+        ::GetProcAddress(shell32Dll, "SHGetKnownFolderPath"));
+    if (!shGetKnownFolderPath) {
+      return nullptr;
+    }
+  }
+  PWSTR path = nullptr;
+  shGetKnownFolderPath(folderId, 0, nullptr, &path);
+  return UniquePtr<wchar_t, LoadedCoTaskMemFreeDeleter>(path);
+}
+
+}  // namespace mozilla