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

[Eli Zaretskii]

> From: Michael Albinus <address@hidden>
> Date: Mon, 21 Apr 2008 09:46:48 +0200
> Cc: 'Emacs-Devel' <address@hidden>,
>       'Michael Albinus' <address@hidden>,
>       'Stefan Monnier' <address@hidden>,
>       'Jason Rumney' <address@hidden>
> 
> I believe, we are speaking about 2 different functions:
> 
> * file-remote-p returns t, if a file is not directly accessible by
>   underlying operating system's means. Such files always need some
>   special file name handler functions in Emacs for proper
>   handling. Such (absolute) file names cannot be used literally
>   outside functions, which support file name handlers.
> 
> * file-mounted-p (as working name) returns t, if a file looks like an
>   ordinary file from the operating system's point of view, but its
>   physical location is on another machine. Examples are nfs, smbfs or
>   sshfs mounts under GNU/Linux, or network shares under W32. This
>   property cannot be detected by file name handler functions. The
>   implementation shall be in the C core.
> 
> These functions are exclusive: file-remote-p and file-mounted-p shall
> not return t for the same filename. Since one function uses the
> filename only for checking the result, and the other function uses
> operating system properties, I don't believe it makes sense to merge
> them into one function.

110% agreement.  And, given several good arguments posted by Andreas,
it sounds like the best implementation for determining whether
accessing a file is likely to be slow would be a simple alist, set by
the user, since only the user knows which filesystems on her machine
cause slowdown.  I don't see how Emacs can determine that by itself
without actually accessing the file.