Re: API for excess DOS file attributes??

[Oleksandr Gavenko]

29.09.2011 23:23, Eli Zaretskii пишет:
> > From: Oleksandr Gavenko<gavenkoa@gmail.com>
> > Date: Thu, 29 Sep 2011 22:59:09 +0300
> >
> > So I think that I can not excess to this data from Emacs
> > (native Windows build).
>
> Not from Lisp, no.
>
> > I try rewrite 'follow-cygwin-symlink' from:
> >
> >     http://www.emacswiki.org/emacs/setup-cygwin.el
> >
> > for more strict conformance of definition of symbolic link
> > in Cygwin (from 'cygwin-ug-net-nochunks.html'):
> >
> >     The file style symlinks are files containing a magic cookie
> >     followed by the path to which the link points. They are marked
> >     with the System DOS attribute so that only files with that
> >     attribute have to be read to determine whether or not the file is
> >     a symbolic link.
>
> What's in setup-cygwin.el is about as good as you can get in Lisp.  A
> better solution would be to add to file-symlink-p and
> make-symbolic-link the ability to recognize and create Cygwin-style
> symlink (and Windows 7 style symlink as well), but that requires
> changes on the C level.
OK.

I get next new definition of 'follow-cygwin-symlink', which work with
new (to Cygwin 1.7) style of links:

(when (eq windows-system 'w32)

  (defun follow-cygwin-symlink ()
    "Follow new-style (and also UCS-16) Cygwin symlinks."
    (save-excursion
      (goto-char 0)
      (when (looking-at "!<symlink>\xff\xfe")
        (find-alternate-file
         (substring
          (decode-coding-string
           (buffer-substring (match-end 0) (point-max))
           'utf-16-le)
          0 -1)                           ; -1 for stripping final \0.
         ))))
  (add-hook 'find-file-hooks 'follow-cygwin-symlink)

 )

I don't incorporate it back to emacswiki as don't understand some part
of old code.

Maintainer of this file is Drew Adams, but I don't know how contact
with him.