/* Copyright (c) 2005, 2021, Oracle and/or its affiliates.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   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, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA */

// First include (the generated) my_config.h, to get correct platform defines.
#include "my_config.h"
#include <stdlib.h>
#include <ctype.h>
#include <mysql/plugin_ftparser.h>
#include <m_ctype.h>


static long number_of_calls= 0; /* for SHOW STATUS, see below */

/*
  Simple full-text parser plugin that acts as a replacement for the
  built-in full-text parser:
  - All non-whitespace characters are significant and are interpreted as
   "word characters."
  - Whitespace characters are space, tab, CR, LF.
  - There is no minimum word length.  Non-whitespace sequences of one
    character or longer are words.
  - Stopwords are used in non-boolean mode, not used in boolean mode.
*/

/*
  simple_parser interface functions:

  Plugin declaration functions:
  - simple_parser_plugin_init()
  - simple_parser_plugin_deinit()

  Parser descriptor functions:
  - simple_parser_parse()
  - simple_parser_init()
  - simple_parser_deinit()
*/


/*
  Initialize the parser plugin at server start or plugin installation.

  SYNOPSIS
    simple_parser_plugin_init()

  DESCRIPTION
    Does nothing.

  RETURN VALUE
    0                    success
    1                    failure (cannot happen)
*/

static int simple_parser_plugin_init(void *arg MY_ATTRIBUTE((unused)))
{
  return(0);
}


/*
  Terminate the parser plugin at server shutdown or plugin deinstallation.

  SYNOPSIS
    simple_parser_plugin_deinit()
    Does nothing.

  RETURN VALUE
    0                    success
    1                    failure (cannot happen)

*/

static int simple_parser_plugin_deinit(void *arg MY_ATTRIBUTE((unused)))
{
  return(0);
}


/*
  Initialize the parser on the first use in the query

  SYNOPSIS
    simple_parser_init()

  DESCRIPTION
    Does nothing.

  RETURN VALUE
    0                    success
    1                    failure (cannot happen)
*/

static int simple_parser_init(MYSQL_FTPARSER_PARAM *param
                              MY_ATTRIBUTE((unused)))
{
  return(0);
}


/*
  Terminate the parser at the end of the query

  SYNOPSIS
    simple_parser_deinit()

  DESCRIPTION
    Does nothing.

  RETURN VALUE
    0                    success
    1                    failure (cannot happen)
*/

static int simple_parser_deinit(MYSQL_FTPARSER_PARAM *param
                                MY_ATTRIBUTE((unused)))
{
  return(0);
}


/*
  Pass a word back to the server.

  SYNOPSIS
    add_word()
      param              parsing context of the plugin
      word               a word
      len                word length

  DESCRIPTION
    Fill in boolean metadata for the word (if parsing in boolean mode)
    and pass the word to the server.  The server adds the word to
    a full-text index when parsing for indexing, or adds the word to
    the list of search terms when parsing a search string.
*/

static void add_word(MYSQL_FTPARSER_PARAM *param, char *word, size_t len)
{
  MYSQL_FTPARSER_BOOLEAN_INFO bool_info=
    { FT_TOKEN_WORD, 0, 0, 0, 0, (word - param->doc), ' ', 0 };

  param->mysql_add_word(param, word, len, &bool_info);
}

/*
  Parse a document or a search query.

  SYNOPSIS
    simple_parser_parse()
      param              parsing context

  DESCRIPTION
    This is the main plugin function which is called to parse
    a document or a search query. The call mode is set in
    param->mode.  This function simply splits the text into words
    and passes every word to the MySQL full-text indexing engine.

  RETURN VALUE
    0                    success
    1                    failure (cannot happen)
*/

static int simple_parser_parse(MYSQL_FTPARSER_PARAM *param)
{
  char *end, *start, *docend= param->doc + param->length;

  number_of_calls++;

  for (end= start= param->doc;; end++)
  {
    if (end == docend)
    {
      if (end > start)
        add_word(param, start, end - start);
      break;
    }
    else if (my_isspace(param->cs, *end))
    {
      if (end > start)
        add_word(param, start, end - start);
      start= end + 1;
    }
  }
  return(0);
}


/*
  Plugin type-specific descriptor
*/

static struct st_mysql_ftparser simple_parser_descriptor=
{
  MYSQL_FTPARSER_INTERFACE_VERSION, /* interface version      */
  simple_parser_parse,              /* parsing function       */
  simple_parser_init,               /* parser init function   */
  simple_parser_deinit              /* parser deinit function */
};

/*
  Plugin status variables for SHOW STATUS
*/

static struct st_mysql_show_var simple_status[]=
{
  {"static",     (char *)"just a static text",     SHOW_CHAR, SHOW_SCOPE_GLOBAL},
  {"called",     (char *)&number_of_calls, SHOW_LONG, SHOW_SCOPE_GLOBAL},
  {0,0,0, SHOW_SCOPE_GLOBAL}
};

/*
  Plugin system variables.
*/

static long     sysvar_one_value;
static char     *sysvar_two_value;

static MYSQL_SYSVAR_LONG(simple_sysvar_one, sysvar_one_value,
  PLUGIN_VAR_RQCMDARG,
  "Simple fulltext parser example system variable number one. Give a number.",
  NULL, NULL, 77L, 7L, 777L, 0);

static MYSQL_SYSVAR_STR(simple_sysvar_two, sysvar_two_value,
  PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_MEMALLOC,
  "Simple fulltext parser example system variable number two. Give a string.",
  NULL, NULL, "simple sysvar two default");

static MYSQL_THDVAR_LONG(simple_thdvar_one,
  PLUGIN_VAR_RQCMDARG,
  "Simple fulltext parser example thread variable number one. Give a number.",
  NULL, NULL, 88L, 8L, 888L, 0);

static MYSQL_THDVAR_STR(simple_thdvar_two,
  PLUGIN_VAR_RQCMDARG | PLUGIN_VAR_MEMALLOC,
  "Simple fulltext parser example thread variable number two. Give a string.",
  NULL, NULL, "simple thdvar two default");

static struct st_mysql_sys_var* simple_system_variables[]= {
  MYSQL_SYSVAR(simple_sysvar_one),
  MYSQL_SYSVAR(simple_sysvar_two),
  MYSQL_SYSVAR(simple_thdvar_one),
  MYSQL_SYSVAR(simple_thdvar_two),
  NULL
};

/*
  Plugin library descriptor
*/

mysql_declare_plugin(ftexample)
{
  MYSQL_FTPARSER_PLUGIN,      /* type                            */
  &simple_parser_descriptor,  /* descriptor                      */
  "simple_parser",            /* name                            */
  "Oracle Corp",              /* author                          */
  "Simple Full-Text Parser",  /* description                     */
  PLUGIN_LICENSE_GPL,
  simple_parser_plugin_init,  /* init function (when loaded)     */
  simple_parser_plugin_deinit,/* deinit function (when unloaded) */
  0x0001,                     /* version                         */
  simple_status,              /* status variables                */
  simple_system_variables,    /* system variables                */
  NULL,
  0,
}
mysql_declare_plugin_end;

