[merge][#297831] use open/fchdir to save and restore cwd

[Martin Pool]

On Fri, Nov 21, 2008 at 2:23 AM, John Arbash Meinel
<john at arbash-meinel.com> wrote:
> +            while entry != NULL:
> +                # Unlike most libc functions, readdir needs errno set to 0
> +                # beforehand so that eof can be distinguished from
> errors.  See
> +                # <https://bugs.launchpad.net/bzr/+bug/279381>
> +                while True:
> +                    errno = 0;
> +                    entry = readdir(the_dir)
> +
>
> ^- We don't need the semicolon at the end of "errno = 0"  (I realize you
> probably didn't put it there.)

Fixed.

> +        if -1 != orig_dir_fd:
> +            if -1 == fchdir(orig_dir_fd):
> +                raise OSError(errno, strerror(errno))
> +            if -1 == close(orig_dir_fd):
> +                raise OSError(errno, strerror(errno))
> +
>
> ^- Do we want to raise before we close the orig_dir_fd?

Yes.

> BB:approve
>
> (I have confirmed that it works on cygwin at least.)
>
> I'm a tiny bit concerned about the implications on cygwin, in that we
> are holding open a file handle, but I'm not very concerned.

Because of a limited number of file handles, or ...?

I would not be surprised if fchdir can't be done locally and needs to
be emulated in some way in cygwin.  Can we use the _walkdirs_win32
from inside cygwin?

Anyhow, I've sent it to pqm.

-- 
Martin <http://launchpad.net/~mbp/>