testing for a remote file to include file on a Windows mapped drive

[Drew Adams]

I have some code that needs to avoid some particular processing when the
current input might name a remote file. I don't want the code to try to
contact anything remote in this case.

In Windows, you can map a remote directory to a virtual drive. So, for
instance, "h:foo" or "h:/foo" might represent a remote file. But the same
name would represent a local file if drive `h' is local, not mapped.

How can I test in Emacs, for Windows, whether a drive is local or mapped, in
order to determine whether "h:foo" might be local or remote?

AFAICT, the various ways Emacs uses to test file-name syntax to determine
remoteness do not take Windows drive mapping into account. I don't know if
that's a problem for Emacs in general (why wouldn't it be?), but it is a
problem for my use case.

I've looked at these. None does what I need.

. file-remote-p
. ffap-file-remote-p
. dired-sort-menu-remote-p
  "\\`/\\([^@:/address@hidden)?\\([^:/]+\\):"
. ange-ftp-name-format
  "\\`/\\(\\([^/:]*\\)@\\)?\\([^@/:]*[^@/:.]\\):\\(.*\\)"
. remote (ange-ftp) filenames (see make-auto-save-file-name)
  "^/address@hidden:"
. ffap-ftp-regexp
  "\\`/[^/:]+:"

Suggestions?