// -*- C++ -*-
/* Copyright (C) 1989, 1990, 1991, 1992 Free Software Foundation, Inc.
     Written by James Clark (jjc@jclark.com)

This file is part of groff.

groff 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 2, or (at your option) any later
version.

groff 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 groff; see the file COPYING.  If not, write to the Free Software
Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */

#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>

#include "posix.h"
#include "lib.h"
#include "errarg.h"
#include "error.h"

extern "C" {
  // Sun's stdlib.h fails to declare this.
  char *mktemp(char *);
  int mkstemp(char *);
}

// If this is set, create temporary files there
#define GROFF_TMPDIR_ENVVAR "GROFF_TMPDIR"
// otherwise if this is set, create temporary files there
#define TMPDIR_ENVVAR "TMPDIR"
#ifdef __MSDOS__
// otherwise create temporary files here.
// (cannot assume there is "/tmp" on every drive on MSDOS)
#define DEFAULT_TMPDIR "c:"
// Use this as the prefix for temporary filenames.
#define TMPFILE_PREFIX  "gf"
#else
// otherwise create temporary files here.
#define DEFAULT_TMPDIR "/tmp"
// Use this as the prefix for temporary filenames.
#define TMPFILE_PREFIX  "groff"
#endif

// Open a temporary file with fatal error on failure.

FILE *xtmpfile()
{
  const char *dir = getenv(GROFF_TMPDIR_ENVVAR);
  if (!dir) {
    dir = getenv(TMPDIR_ENVVAR);
    if (!dir)
      dir = DEFAULT_TMPDIR;
  }
  
  const char *p = strrchr(dir, '/');
  int needs_slash = (!p || p[1]);
#ifdef __MSDOS__
  if (needs_slash)
    {
      const char *bslash = strrchr(dir, '\\');
      if (!p || bslash > p)
	p = bslash;
      if (p && !p[1])
	needs_slash = 0;
    }
#endif
  char *templ = new char[strlen(dir) + needs_slash
			    + sizeof(TMPFILE_PREFIX) - 1 + 6 + 1];
  strcpy(templ, dir);
  if (needs_slash)
    strcat(templ, "/");
  strcat(templ, TMPFILE_PREFIX);
  strcat(templ, "XXXXXX");

#ifdef HAVE_MKSTEMP
  errno = 0;
  int fd = mkstemp(templ);
  if (fd < 0)
    fatal("cannot create temporary file: %1", strerror(errno));
  errno = 0;
  FILE *fp = fdopen(fd, "wb+");	// users of `xtmpfile' seem to need binary I/O
  if (!fp)
    fatal("fdopen: %1", strerror(errno));
#else /* not HAVE_MKSTEMP */
  if (!mktemp(templ) || !templ[0])
    fatal("cannot create file name for temporary file");
  errno = 0;
  FILE *fp = fopen(templ, "wb+");
  if (!fp)
    fatal("cannot open `%1': %2", templ, strerror(errno));
#endif /* not HAVE_MKSTEMP */
  if (unlink(templ) < 0)
    error("cannot unlink `%1': %2", templ, strerror(errno));
  a_delete templ;
  return fp;
}

#if 0
// If you're not running Unix, the following will do:
FILE *xtmpfile()
{
  FILE *fp = tmpfile();
  if (!fp)
    fatal("couldn't create temporary file");
  return fp;
}
#endif
