/* xfts.c -- a wrapper for fts_open

   Copyright (C) 2003, 2005-2007, 2009 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* Written by Jim Meyering.  */

#include <config.h>

#include <stdbool.h>
#include <stdlib.h>

#include "error.h"

#include "gettext.h"
#define _(msgid) gettext (msgid)

#include "quote.h"
#include "xalloc.h"
#include "xfts.h"

/* Fail with a proper diagnostic if fts_open fails.  */

FTS *
xfts_open (char * const *argv, int options,
           int (*compar) (const FTSENT **, const FTSENT **))
{
  FTS *fts = fts_open (argv, options | FTS_CWDFD, compar);
  if (fts == NULL)
    {
      /* This can fail in three ways: out of memory, invalid bit_flags,
         and one or more of the FILES is an empty string.  We could try
         to decipher that errno==EINVAL means invalid bit_flags and
         errno==ENOENT means there's an empty string, but that seems wrong.
         Ideally, fts_open would return a proper error indicator.  For now,
         we'll presume that the bit_flags are valid and just check for
         empty strings.  */
      bool invalid_arg = false;
      for (; *argv; ++argv)
        {
          if (**argv == '\0')
            invalid_arg = true;
        }
      if (invalid_arg)
        error (EXIT_FAILURE, 0, _("invalid argument: %s"), quote (""));
      else
        xalloc_die ();
    }

  return fts;
}

/* When fts_read returns FTS_DC to indicate a directory cycle,
   it may or may not indicate a real problem.  When a program like
   chgrp performs a recursive traversal that requires traversing
   symbolic links, it is *not* a problem.  However, when invoked
   with "-P -R", it deserves a warning.  The fts_options member
   records the options that control this aspect of fts's behavior,
   so test that.  */
bool
cycle_warning_required (FTS const *fts, FTSENT const *ent)
{
#define ISSET(Fts,Opt) ((Fts)->fts_options & (Opt))
  /* When dereferencing no symlinks, or when dereferencing only
     those listed on the command line and we're not processing
     a command-line argument, then a cycle is a serious problem. */
  return ((ISSET (fts, FTS_PHYSICAL) && !ISSET (fts, FTS_COMFOLLOW))
          || (ISSET (fts, FTS_PHYSICAL) && ISSET (fts, FTS_COMFOLLOW)
              && ent->fts_level != FTS_ROOTLEVEL));
}