[PATCH] D99212: [Support] Fix Windows 7 path handling

[Alexandre Ganea via Phabricator via llvm-commits]

aganea updated this revision to Diff 332972.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99212/new/

https://reviews.llvm.org/D99212

Files:
  llvm/lib/Support/Windows/Path.inc


Index: llvm/lib/Support/Windows/Path.inc
===================================================================
--- llvm/lib/Support/Windows/Path.inc
+++ llvm/lib/Support/Windows/Path.inc
@@ -402,8 +402,21 @@
 }
 
 static std::error_code setDeleteDisposition(HANDLE Handle, bool Delete) {
-  // First, check if the file is on a network (non-local) drive. If so, don't
-  // set DeleteFile to true, since it prevents opening the file for writes.
+  // Clear the FILE_DISPOSITION_INFO flag first, before checking if it's a
+  // network file. On Windows 7 the function realPathFromHandle() below fails
+  // if the FILE_DISPOSITION_INFO flag was already set by a prior call.
+  FILE_DISPOSITION_INFO Disposition;
+  Disposition.DeleteFile = false;
+  if (!SetFileInformationByHandle(Handle, FileDispositionInfo, &Disposition,
+                                  sizeof(Disposition)))
+    return mapWindowsError(::GetLastError());
+  if (!Delete)
+    return std::error_code();
+
+  // Check if the file is on a network (non-local) drive. If so, don't
+  // continue when DeleteFile is true, since it prevents opening the file for
+  // writes. Note -- this will leak temporary files on disk, but only when the
+  // target file is on a network drive.
   SmallVector<wchar_t, 128> FinalPath;
   if (std::error_code EC = realPathFromHandle(Handle, FinalPath))
     return EC;
@@ -415,9 +428,9 @@
   if (!IsLocal)
     return std::error_code();
 
-  // The file is on a local drive, set the DeleteFile to true.
-  FILE_DISPOSITION_INFO Disposition;
-  Disposition.DeleteFile = Delete;
+  // The file is on a local drive, we can safely set FILE_DISPOSITION_INFO's
+  // flag.
+  Disposition.DeleteFile = true;
   if (!SetFileInformationByHandle(Handle, FileDispositionInfo, &Disposition,
                                   sizeof(Disposition)))
     return mapWindowsError(::GetLastError());


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D99212.332972.patch
Type: text/x-patch
Size: 1883 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20210324/cbd7fa0f/attachment.bin>