/* server-help.h - Helper functions for writing Assuan servers.

 *  Copyright (C) 2003, 2009, 2010 g10 Code GmbH

 *

 * This file is part of GnuPG.

 *

 * This file is free software; you can redistribute it and/or modify

 * it under the terms of either

 *

 *   - the GNU Lesser General Public License as published by the Free

 *     Software Foundation; either version 3 of the License, or (at

 *     your option) any later version.

 *

 * or

 *

 *   - the GNU General Public License as published by the Free

 *     Software Foundation; either version 2 of the License, or (at

 *     your option) any later version.

 *

 * or both in parallel, as here.

 *

 * This file 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 <https://www.gnu.org/licenses/>.

 */

#include <config.h>

#include <string.h>

#include "util.h"

#include "server-help.h"

static GPGRT_INLINE gpg_error_t

my_error (int e)

{

  return gpg_err_make (default_errsource, (e));

}

static GPGRT_INLINE gpg_error_t

my_error_from_syserror (void)

{

  return gpg_err_make (default_errsource, gpg_err_code_from_syserror ());

}

/* Skip over options in LINE.

   Blanks after the options are also removed.  Options are indicated

   by two leading dashes followed by a string consisting of non-space

   characters.  The special option "--" indicates an explicit end of

   options; all what follows will not be considered an option.  The

   first no-option string also indicates the end of option parsing. */

char *

skip_options (const char *line)

{

  while (spacep (line))

    line++;

  while (*line == '-' && line[1] == '-')

    {

      while (*line && !spacep (line))

        line++;

      while (spacep (line))

        line++;

    }

  return (char*) line;

}

/* Check whether the option NAME appears in LINE.  */

int

has_option (const char *line, const char *name)

{

  const char *s;

  int n = strlen (name);

  s = strstr (line, name);

  if (s && s >= skip_options (line))

    return 0;

  return (s && (s == line || spacep (s-1)) && (!s[n] || spacep (s+n)));

}

/* Same as has_option but only considers options at the begin of the

   line.  This is useful for commands which allow arbitrary strings on

   the line.  */

int

has_leading_option (const char *line, const char *name)

{

  const char *s;

  int n;

  if (name[0] != '-' || name[1] != '-' || !name[2] || spacep (name+2))

    return 0;

  n = strlen (name);

  while ( *line == '-' && line[1] == '-' )

    {

      s = line;

      while (*line && !spacep (line))

        line++;

      if (n == (line - s) && !strncmp (s, name, n))

        return 1;

      while (spacep (line))

        line++;

    }

  return 0;

}

/* Same as has_option but does only test for the name of the option

   and ignores an argument, i.e. with NAME being "--hash" it would

   return a pointer for "--hash" as well as for "--hash=foo".  If

   there is no such option NULL is returned.  The pointer returned

   points right behind the option name, this may be an equal sign, Nul

   or a space.  */

const char *

has_option_name (const char *line, const char *name)

{

  const char *s;

  int n = strlen (name);

  s = strstr (line, name);

  return (s && (s == line || spacep (s-1))

          && (!s[n] || spacep (s+n) || s[n] == '=')) ? (s+n) : NULL;

}

/* Parse an option with the format "--NAME=VALUE" which must occur in

 * LINE before a double-dash.  LINE is written to but not modified by

 * this function.  If the option is found and has a value the value is

 * stored as a malloced string at R_VALUE.  If the option was not

 * found or an error occurred NULL is stored there.  Note that

 * currently the value must be a string without any space; we may

 * eventually update this function to allow for a quoted value.  */

gpg_error_t

get_option_value (char *line, const char *name, char **r_value)

{

  char *p, *pend;

  int c;

  *r_value = NULL;

  p = (char*)has_option_name (line, name);

  if (!p || p >= skip_options (line))

    return 0;

  if (*p != '=' || !p[1] || spacep (p+1))

    return my_error (GPG_ERR_INV_ARG);

  p++;

  for (pend = p; *pend && !spacep (pend); pend++)

    ;

  c = *pend;

  *pend = 0;

  *r_value = xtrystrdup (p);

  *pend = c;

  if (!p)

    return my_error_from_syserror ();

  return 0;

}

/* Return a pointer to the argument of the option with NAME.  If such

   an option is not given, NULL is returned. */

char *

option_value (const char *line, const char *name)

{

  char *s;

  int n = strlen (name);

  s = strstr (line, name);

  if (s && s >= skip_options (line))

    return NULL;

  if (s && (s == line || spacep (s-1))

      && s[n] && (spacep (s+n) || s[n] == '='))

    {

      s += n + 1;

      s += strspn (s, " ");

      if (*s && !spacep(s))

        return s;

    }

  return NULL;

}