command_word_completion_function (hint_text, state)
     const char *hint_text;
     int state;
{
  static char *hint = (char *)NULL;
  static char *path = (char *)NULL;
  static char *val = (char *)NULL;
  static char *filename_hint = (char *)NULL;
  static char *fnhint = (char *)NULL;
  static char *dequoted_hint = (char *)NULL;
  static char *directory_part = (char *)NULL;
  static char **glob_matches = (char **)NULL;
  static int path_index, hint_len, istate, igncase;
  static int mapping_over, local_index, searching_path, hint_is_dir;
  static int old_glob_ignore_case, globpat;
  static SHELL_VAR **varlist = (SHELL_VAR **)NULL;
#if defined (ALIAS)
  static alias_t **alias_list = (alias_t **)NULL;
#endif /* ALIAS */
  char *temp, *cval;

  /* We have to map over the possibilities for command words.  If we have
     no state, then make one just for that purpose. */
  if (state == 0)
    {
      rl_filename_stat_hook = bash_command_name_stat_hook;

      if (dequoted_hint && dequoted_hint != hint)
	free (dequoted_hint);
      if (hint)
	free (hint);

      mapping_over = searching_path = 0;
      hint_is_dir = CMD_IS_DIR (hint_text);
      val = (char *)NULL;

      temp = rl_variable_value ("completion-ignore-case");
      igncase = RL_BOOLEAN_VARIABLE_VALUE (temp);

      if (glob_matches)
	{
	  free (glob_matches);
	  glob_matches = (char **)NULL;
	}

      globpat = completion_glob_pattern ((char *)hint_text);

      /* If this is an absolute program name, do not check it against
	 aliases, reserved words, functions or builtins.  We must check
	 whether or not it is unique, and, if so, whether that filename
	 is executable. */
      if (globpat || absolute_program (hint_text))
	{
	  /* Perform tilde expansion on what's passed, so we don't end up
	     passing filenames with tildes directly to stat().  The rest of
	     the shell doesn't do variable expansion on the word following
	     the tilde, so we don't do it here even if direxpand is set. */
	  if (*hint_text == '~')
	    {
	      hint = bash_tilde_expand (hint_text, 0);
	      directory_part = savestring (hint_text);
	      temp = strchr (directory_part, '/');
	      if (temp)
		*temp = 0;
	      else
		{
		  free (directory_part);
		  directory_part = (char *)NULL;
		}
	    }
	  else if (dircomplete_expand)
	    {
	      hint = savestring (hint_text);
	      bash_directory_completion_hook (&hint);
	    }
	  else
	    hint = savestring (hint_text);

	  dequoted_hint = hint;
	  /* If readline's completer found a quote character somewhere, but
	     didn't set the quote character, there must have been a quote
	     character embedded in the filename.  It can't be at the start of
	     the filename, so we need to dequote the filename before we look
	     in the file system for it. */
	  if (rl_completion_found_quote && rl_completion_quote_character == 0)
	    {
	      dequoted_hint = bash_dequote_filename (hint, 0);
	      free (hint);
	      hint = dequoted_hint;
	    }
	  hint_len = strlen (hint);

	  if (filename_hint)
	    free (filename_hint);

	  fnhint = filename_hint = savestring (hint);

	  istate = 0;

	  if (globpat)
	    {
	      mapping_over = 5;
	      goto globword;
	    }
	  else
	    {
	     if (dircomplete_expand && path_dot_or_dotdot (filename_hint))
		{
		  dircomplete_expand = 0;
		  set_directory_hook ();
		  dircomplete_expand = 1;
		}
	      mapping_over = 4;
	      goto inner;
	    }
	}

      dequoted_hint = hint = savestring (hint_text);
      hint_len = strlen (hint);

      if (rl_completion_found_quote && rl_completion_quote_character == 0)
	dequoted_hint = bash_dequote_filename (hint, 0);
      
      path = get_string_value ("PATH");
      path_index = dot_in_path = 0;

      /* Initialize the variables for each type of command word. */
      local_index = 0;

      if (varlist)
	free (varlist);

      varlist = all_visible_functions ();

#if defined (ALIAS)
      if (alias_list)
	free (alias_list);

      alias_list = all_aliases ();
#endif /* ALIAS */
    }

  /* mapping_over says what we are currently hacking.  Note that every case
     in this list must fall through when there are no more possibilities. */

  switch (mapping_over)
    {
    case 0:			/* Aliases come first. */
#if defined (ALIAS)
      while (alias_list && alias_list[local_index])
	{
	  register char *alias;

	  alias = alias_list[local_index++]->name;

	  if (igncase == 0 && (STREQN (alias, hint, hint_len)))
	    return (savestring (alias));
	  else if (igncase && strncasecmp (alias, hint, hint_len) == 0)
	    return (savestring (alias));
	}
#endif /* ALIAS */
      local_index = 0;
      mapping_over++;

    case 1:			/* Then shell reserved words. */
      {
	while (word_token_alist[local_index].word)
	  {
	    register char *reserved_word;

	    reserved_word = word_token_alist[local_index++].word;

	    if (STREQN (reserved_word, hint, hint_len))
	      return (savestring (reserved_word));
	  }
	local_index = 0;
	mapping_over++;
      }

    case 2:			/* Then function names. */
      while (varlist && varlist[local_index])
	{
	  register char *varname;

	  varname = varlist[local_index++]->name;

	  /* Honor completion-ignore-case for shell function names. */
	  if (igncase == 0 && (STREQN (varname, hint, hint_len)))
	    return (savestring (varname));
	  else if (igncase && strncasecmp (varname, hint, hint_len) == 0)
	    return (savestring (varname));
	}
      local_index = 0;
      mapping_over++;

    case 3:			/* Then shell builtins. */
      for (; local_index < num_shell_builtins; local_index++)
	{
	  /* Ignore it if it doesn't have a function pointer or if it
	     is not currently enabled. */
	  if (!shell_builtins[local_index].function ||
	      (shell_builtins[local_index].flags & BUILTIN_ENABLED) == 0)
	    continue;

	  if (STREQN (shell_builtins[local_index].name, hint, hint_len))
	    {
	      int i = local_index++;

	      return (savestring (shell_builtins[i].name));
	    }
	}
      local_index = 0;
      mapping_over++;
    }

globword:
  /* Limited support for completing command words with globbing chars.  Only
     a single match (multiple matches that end up reducing the number of
     characters in the common prefix are bad) will ever be returned on
     regular completion. */
  if (globpat)
    {
      if (state == 0)
	{
	  glob_ignore_case = igncase;
	  glob_matches = shell_glob_filename (hint);
	  glob_ignore_case = old_glob_ignore_case;

	  if (GLOB_FAILED (glob_matches) || glob_matches == 0)
	    {
	      glob_matches = (char **)NULL;
	      return ((char *)NULL);
	    }

	  local_index = 0;
		
	  if (glob_matches[1] && rl_completion_type == TAB)	/* multiple matches are bad */
	    return ((char *)NULL);
	}

      while (val = glob_matches[local_index++])
        {
	  if (executable_or_directory (val))
	    {
	      if (*hint_text == '~' && directory_part)
		{
		  temp = maybe_restore_tilde (val, directory_part);
		  free (val);
		  val = temp;
		}
	      return (val);
	    }
	  free (val);
        }

      glob_ignore_case = old_glob_ignore_case;
      return ((char *)NULL);
    }

  /* If the text passed is a directory in the current directory, return it
     as a possible match.  Executables in directories in the current
     directory can be specified using relative pathnames and successfully
     executed even when `.' is not in $PATH. */
  if (hint_is_dir)
    {
      hint_is_dir = 0;	/* only return the hint text once */
      return (savestring (hint_text));
    }
    
  /* Repeatedly call filename_completion_function while we have
     members of PATH left.  Question:  should we stat each file?
     Answer: we call executable_file () on each file. */
 outer:

  istate = (val != (char *)NULL);

  if (istate == 0)
    {
      char *current_path;

      /* Get the next directory from the path.  If there is none, then we
	 are all done. */
      if (path == 0 || path[path_index] == 0 ||
	  (current_path = extract_colon_unit (path, &path_index)) == 0)
	return ((char *)NULL);

      searching_path = 1;
      if (*current_path == 0)
	{
	  free (current_path);
	  current_path = savestring (".");
	}

      if (*current_path == '~')
	{
	  char *t;

	  t = bash_tilde_expand (current_path, 0);
	  free (current_path);
	  current_path = t;
	}

      if (current_path[0] == '.' && current_path[1] == '\0')
	dot_in_path = 1;

      if (fnhint && fnhint != filename_hint)
	free (fnhint);
      if (filename_hint)
	free (filename_hint);

      filename_hint = sh_makepath (current_path, hint, 0);
      /* Need a quoted version (though it doesn't matter much in most
	 cases) because rl_filename_completion_function dequotes the
	 filename it gets, assuming that it's been quoted as part of
	 the input line buffer. */
      if (strpbrk (filename_hint, "\"'\\"))
	fnhint = sh_backslash_quote (filename_hint, filename_bstab, 0);
      else
	fnhint = filename_hint;
      free (current_path);		/* XXX */
    }

 inner:
  val = rl_filename_completion_function (fnhint, istate);
  if (mapping_over == 4 && dircomplete_expand)
    set_directory_hook ();

  istate = 1;

  if (val == 0)
    {
      /* If the hint text is an absolute program, then don't bother
	 searching through PATH. */
      if (absolute_program (hint))
	return ((char *)NULL);

      goto outer;
    }
  else
    {
      int match, freetemp;

      if (absolute_program (hint))
	{
	  if (igncase == 0)
	    match = strncmp (val, hint, hint_len) == 0;
	  else
	    match = strncasecmp (val, hint, hint_len) == 0;

	  /* If we performed tilde expansion, restore the original
	     filename. */
	  if (*hint_text == '~')
	    temp = maybe_restore_tilde (val, directory_part);
	  else
	    temp = savestring (val);
	  freetemp = 1;
	}
      else
	{
	  temp = strrchr (val, '/');

	  if (temp)
	    {
	      temp++;
	      if (igncase == 0)
		freetemp = match = strncmp (temp, hint, hint_len) == 0;
	      else
		freetemp = match = strncasecmp (temp, hint, hint_len) == 0;
	      if (match)
		temp = savestring (temp);
	    }
	  else
	    freetemp = match = 0;
	}

      /* If we have found a match, and it is an executable file, return it.
	 We don't return directory names when searching $PATH, since the
	 bash execution code won't find executables in directories which
	 appear in directories in $PATH when they're specified using
	 relative pathnames.  */
#if 0
      /* If we're not searching $PATH and we have a relative pathname, we
	 need to re-canonicalize it before testing whether or not it's an
	 executable or a directory so the shell treats .. relative to $PWD
	 according to the physical/logical option.  The shell already
	 canonicalizes the directory name in order to tell readline where
	 to look, so not doing it here will be inconsistent. */
      /* XXX -- currently not used -- will introduce more inconsistency,
	 since shell does not canonicalize ../foo before passing it to
	 shell_execve().  */
      if (match && searching_path == 0 && *val == '.')
	{
	  char *t, *t1;

	  t = get_working_directory ("command-word-completion");
	  t1 = make_absolute (val, t);
	  free (t);
	  cval = sh_canonpath (t1, PATH_CHECKDOTDOT|PATH_CHECKEXISTS);
	}
      else
#endif
	cval = val;

      if (match && executable_completion ((searching_path ? val : cval), searching_path))
	{
	  if (cval != val)
	    free (cval);
	  free (val);
	  val = "";		/* So it won't be NULL. */
	  return (temp);
	}
      else
	{
	  if (freetemp)
	    free (temp);
	  if (cval != val)
	    free (cval);
	  free (val);
	  goto inner;
	}
    }
}