/*
 Copyright (c) 2005, 2014, Oracle and/or its affiliates. All rights reserved.

 This program 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; version 2 of the License.

 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 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,
 51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */

#include "sql_priv.h" // SHOW_MY_BOOL
#include "unireg.h"
#include "my_global.h" // REQUIRED by m_string.h
#include "sql_class.h" // set_var.h: THD
#include "sys_vars_shared.h"
#include "sql_locale.h"
#include "sql_plugin.h"
#include "sql_parse.h" // check_table_access
#include "sql_base.h" // close_mysql_tables
#include "key.h" // key_copy
#include "sql_show.h" // remove_status_vars, add_status_vars
#include "strfunc.h" // find_set
#include "sql_acl.h" // *_ACL
#include "records.h" // init_read_record, end_read_record
#include <my_pthread.h>
#include <my_getopt.h>
#include <mysql/plugin_auth.h>
#include <mysql/plugin_validate_password.h>
#include "my_default.h"

#include <algorithm>

using std::min;
using std::max;

#define REPORT_TO_LOG 1
#define REPORT_TO_USER 2

/*
 hidden part of opaque value passed to variable check functions.
 Used to provide a object-like structure to non C++ consumers.
*/
struct st_item_value_holder : public st_mysql_value
{
 Item *item;
};


/*
 stored in bookmark_hash, this structure is never removed from the
 hash and is used to mark a single offset for a thd local variable
 even if plugins have been uninstalled and reinstalled, repeatedly.
 This structure is allocated from plugin_mem_root.

 The key format is as follows:
 1 byte - variable type code
 name_len bytes - variable name
 '0円' - end of key
*/
struct st_bookmark
{
 uint name_len;
 int offset;
 uint version;
 char key[1];
};


/*
 skeleton of a plugin variable - portion of structure common to all.
*/
struct st_mysql_sys_var
{
 MYSQL_PLUGIN_VAR_HEADER;
};


/****************************************************************************
 System Variables support
****************************************************************************/


sys_var *find_sys_var(THD *thd, const char *str, uint length)
{
 sys_var *var;
 DBUG_ENTER("find_sys_var");

 const my_bool *hidden= getopt_constraint_get_hidden_value(str, 0, FALSE);
 if (hidden && *hidden)
 {
 var= NULL;
 goto exit;
 }

 mysql_rwlock_rdlock(&LOCK_system_variables_hash);
 var= intern_find_sys_var(str, length);
 mysql_rwlock_unlock(&LOCK_system_variables_hash);

exit:
 if (!var)
 my_error(ER_UNKNOWN_SYSTEM_VARIABLE, MYF(0), (char*) str);
 DBUG_RETURN(var);
}


void plugin_thdvar_init(THD *thd, bool enable_plugins)
{
 DBUG_ENTER("plugin_thdvar_init");
 
 thd->variables= global_system_variables;
 
 DBUG_VOID_RETURN;
}