/* makepath.c - glue PATH and DIR together into a full pathname. */

/* Copyright (C) 1987-2020 Free Software Foundation, Inc.

   This file is part of GNU Bash, the Bourne Again SHell.

   Bash 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.

   Bash 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 Bash.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <config.h>

#if defined (HAVE_UNISTD_H)
#  ifdef _MINIX
#    include <sys/types.h>
#  endif
#  include <unistd.h>
#endif

#include <bashansi.h>
#include "shell.h"

#include <tilde/tilde.h>

#ifndef NULL
#  define NULL 0
#endif

/* MAKE SURE THESE AGREE WITH ../../externs.h. */

#ifndef MP_DOTILDE
#  define MP_DOTILDE	0x01
#  define MP_DOCWD	0x02
#  define MP_RMDOT	0x04
#  define MP_IGNDOT	0x08
#endif

extern char *get_working_directory PARAMS((char *));

static char *nullpath = "";

/* Take PATH, an element from, e.g., $CDPATH, and DIR, a directory name,
   and paste them together into PATH/DIR.  Tilde expansion is performed on
   PATH if (flags & MP_DOTILDE) is non-zero.  If PATH is NULL or the empty
   string, it is converted to the current directory.  A full pathname is
   used if (flags & MP_DOCWD) is non-zero, otherwise `./' is used.  If
   (flags & MP_RMDOT) is non-zero, any `./' is removed from the beginning
   of DIR.  If (flags & MP_IGNDOT) is non-zero, a PATH that is "." or "./"
   is ignored. */

#define MAKEDOT() \
  do { \
    xpath = (char *)xmalloc (2); \
    xpath[0] = '.'; \
    xpath[1] = '\0'; \
    pathlen = 1; \
  } while (0)

char *
sh_makepath (path, dir, flags)
     const char *path, *dir;
     int flags;
{
  int dirlen, pathlen;
  char *ret, *xpath, *xdir, *r, *s;

  if (path == 0 || *path == '\0')
    {
      if (flags & MP_DOCWD)
	{
	  xpath = get_working_directory ("sh_makepath");
	  if (xpath == 0)
	    {
	      ret = get_string_value ("PWD");
	      if (ret)
		xpath = savestring (ret);
	    }
	  if (xpath == 0)
	    MAKEDOT();
	  else
	    pathlen = strlen (xpath);
	}
      else
	MAKEDOT();
    }
  else if ((flags & MP_IGNDOT) && path[0] == '.' && (path[1] == '\0' ||
						     (path[1] == '/' && path[2] == '\0')))
    {
      xpath = nullpath;
      pathlen = 0;
    }
  else
    {
      xpath = ((flags & MP_DOTILDE) && *path == '~') ? bash_tilde_expand (path, 0) : (char *)path;
      pathlen = strlen (xpath);
    }

  xdir = (char *)dir;
  dirlen = strlen (xdir);
  if ((flags & MP_RMDOT) && dir[0] == '.' && dir[1] == '/')
    {
      xdir += 2;
      dirlen -= 2;
    }

  r = ret = (char *)xmalloc (2 + dirlen + pathlen);
  s = xpath;
  while (*s)
    *r++ = *s++;
  if (s > xpath && s[-1] != '/')
    *r++ = '/';      
  s = xdir;
  while (*r++ = *s++)
    ;
  if (xpath != path && xpath != nullpath)
    free (xpath);
  return (ret);
}