Split rename_handle out of rename on windows

[• rafael]

Summary

I want to use rename_handle in TempFile.

[rnk]

lgtm

[• rafael]

r318725

lib/Support/Windows/Path.inc

if (!SetFileInformationByHandle(FromHandle, FileRenameInfo, &RenameInfo,
     if (Error == ERROR_SUCCESS)
       Error = ERROR_CALL_NOT_IMPLEMENTED; // Wine doesn't always set error code.
     return mapWindowsError(Error);
   }
 
   return std::error_code();
 }
 
+static std::error_code rename_handle(HANDLE Handle, const Twine &To);
+
 std::error_code rename(const Twine &From, const Twine &To) {
   // Convert to utf-16.
   SmallVector<wchar_t, 128> WideFrom;
-  SmallVector<wchar_t, 128> WideTo;
   if (std::error_code EC = widenPath(From, WideFrom))
     return EC;
-  if (std::error_code EC = widenPath(To, WideTo))
-    return EC;
 
   ScopedFileHandle FromHandle;
   // Retry this a few times to defeat badly behaved file system scanners.
   for (unsigned Retry = 0; Retry != 200; ++Retry) {
     if (Retry != 0)
       ::Sleep(10);
     FromHandle =
         ::CreateFileW(WideFrom.begin(), GENERIC_READ | DELETE,
                       FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
                       NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
     if (FromHandle)
       break;
   }
   if (!FromHandle)
     return mapWindowsError(GetLastError());
 
+  return rename_handle(FromHandle, To);
+}
+
+static std::error_code rename_handle(HANDLE FromHandle, const Twine &To) {
+  SmallVector<wchar_t, 128> WideTo;
+  if (std::error_code EC = widenPath(To, WideTo))
+    return EC;
+
   // We normally expect this loop to succeed after a few iterations. If it
   // requires more than 200 tries, it's more likely that the failures are due to
   // a true error, so stop trying.
   for (unsigned Retry = 0; Retry != 200; ++Retry) {
     auto EC = rename_internal(FromHandle, To, true);
 
     if (EC ==
         std::error_code(ERROR_CALL_NOT_IMPLEMENTED, std::system_category())) {
       // Wine doesn't support SetFileInformationByHandle in rename_internal.
       // Fall back to MoveFileEx.
+      SmallVector<wchar_t, MAX_PATH> WideFrom;
+      if (std::error_code EC2 = realPathFromHandle(FromHandle, WideFrom))
+        return EC2;
       if (::MoveFileExW(WideFrom.begin(), WideTo.begin(),
                         MOVEFILE_REPLACE_EXISTING))
         return std::error_code();
       return mapWindowsError(GetLastError());
     }
 
     if (!EC || EC != errc::permission_denied)
       return EC;