From ed84cbeb3e57f7f45a1ed5ccb85d44e781f766a7 Mon Sep 17 00:00:00 2001
From: firewave <firewave@users.noreply.github.com>
Date: Sat, 29 Nov 2025 16:18:16 +0100
Subject: [PATCH] fixed #583 - fall back to `GetFileInformationByHandle()` when
 `GetFileInformationByHandleEx()` fails in
 `simplecpp::FileDataCache::getFileId()`

Co-authored-by: willenbr24 <willenbr24@users.noreply.github.com>
---
 simplecpp.cpp | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/simplecpp.cpp b/simplecpp.cpp
index ef891eb1..9ce846d9 100644
--- a/simplecpp.cpp
+++ b/simplecpp.cpp
@@ -3126,7 +3126,21 @@ bool simplecpp::FileDataCache::getFileId(const std::string &path, FileID &id)
     if (hFile == INVALID_HANDLE_VALUE)
         return false;
 
-    const BOOL ret = GetFileInformationByHandleEx(hFile, FileIdInfo, &id.fileIdInfo, sizeof(id.fileIdInfo));
+    BOOL ret = GetFileInformationByHandleEx(hFile, FileIdInfo, &id.fileIdInfo, sizeof(id.fileIdInfo));
+    if (!ret) {
+        const DWORD err = GetLastError();
+        if (err == ERROR_INVALID_PARAMETER || // encountered when using a non-NTFS filesystem e.g. exFAT
+            err == ERROR_NOT_SUPPORTED) // encountered on Windows Server Core (used as a Docker container)
+        {
+            BY_HANDLE_FILE_INFORMATION fileInfo;
+            ret = GetFileInformationByHandle(hFile, &fileInfo);
+            if (ret) {
+                id.fileIdInfo.VolumeSerialNumber = static_cast<std::uint64_t>(fileInfo.dwVolumeSerialNumber);
+                id.fileIdInfo.FileId.IdentifierHi = static_cast<std::uint64_t>(fileInfo.nFileIndexHigh);
+                id.fileIdInfo.FileId.IdentifierLo = static_cast<std::uint64_t>(fileInfo.nFileIndexLow);
+            }
+        }
+    }
 
     CloseHandle(hFile);