FM / private

/usr/include/mysql/server/private

Name	Size	Mode	Actions
atomic/	-	0755	rm
data/	-	0755	rm
providers/	-	0755	rm
aligned.h	1136	0644	edit dl rm
aria_backup.h	1787	0644	edit dl rm
assume_aligned.h	2350	0644	edit dl rm
authors.h	10141	0644	edit dl rm
backup.h	1703	0644	edit dl rm
bounded_queue.h	6093	0644	edit dl rm
client_settings.h	1935	0644	edit dl rm
compat56.h	2280	0644	edit dl rm
config.h	14543	0644	edit dl rm
contributors.h	4878	0644	edit dl rm
create_options.h	4193	0644	edit dl rm
create_tmp_table.h	2808	0644	edit dl rm
cset_narrowing.h	3968	0644	edit dl rm
custom_conf.h	1082	0644	edit dl rm
datadict.h	1700	0644	edit dl rm
ddl_log.h	12807	0644	edit dl rm
debug.h	1234	0644	edit dl rm
debug_sync.h	2046	0644	edit dl rm
derived_handler.h	2379	0644	edit dl rm
derror.h	980	0644	edit dl rm
des_key_file.h	1236	0644	edit dl rm
discover.h	1570	0644	edit dl rm
dur_prop.h	1082	0644	edit dl rm
embedded_priv.h	1733	0644	edit dl rm
events.h	4704	0644	edit dl rm
event_data_objects.h	4187	0644	edit dl rm
event_db_repository.h	3648	0644	edit dl rm
event_parse_data.h	2899	0644	edit dl rm
event_queue.h	3438	0644	edit dl rm
event_scheduler.h	3290	0644	edit dl rm
field.h	222336	0644	edit dl rm
field_comp.h	1174	0644	edit dl rm
filesort.h	7283	0644	edit dl rm
filesort_utils.h	8195	0644	edit dl rm
ft_global.h	3113	0644	edit dl rm
gcalc_slicescan.h	17272	0644	edit dl rm
gcalc_tools.h	11900	0644	edit dl rm
grant.h	2758	0644	edit dl rm
group_by_handler.h	3534	0644	edit dl rm
gstream.h	2437	0644	edit dl rm
handler.h	199730	0644	edit dl rm
handle_connections_win.h	884	0644	edit dl rm
hash.h	4452	0644	edit dl rm
hash_filo.h	5688	0644	edit dl rm
ha_handler_stats.h	2335	0644	edit dl rm
ha_partition.h	64696	0644	edit dl rm
ha_sequence.h	6245	0644	edit dl rm
heap.h	9480	0644	edit dl rm
hostname.h	5419	0644	edit dl rm
ilist.h	7237	0644	edit dl rm
init.h	852	0644	edit dl rm
innodb_priv.h	1319	0644	edit dl rm
item.h	283188	0644	edit dl rm
item_cmpfunc.h	135071	0644	edit dl rm
item_create.h	11508	0644	edit dl rm
item_func.h	138638	0644	edit dl rm
item_geofunc.h	39612	0644	edit dl rm
item_jsonfunc.h	25264	0644	edit dl rm
item_row.h	5229	0644	edit dl rm
item_strfunc.h	74995	0644	edit dl rm
item_subselect.h	59028	0644	edit dl rm
item_sum.h	72695	0644	edit dl rm
item_timefunc.h	65896	0644	edit dl rm
item_vers.h	4413	0644	edit dl rm
item_windowfunc.h	34556	0644	edit dl rm
item_xmlfunc.h	4650	0644	edit dl rm
json_table.h	9667	0644	edit dl rm
key.h	2132	0644	edit dl rm
keycaches.h	1995	0644	edit dl rm
lex.h	29840	0644	edit dl rm
lex_charset.h	24313	0644	edit dl rm
lex_hash.h	143108	0644	edit dl rm
lex_ident.h	2122	0644	edit dl rm
lex_string.h	4077	0644	edit dl rm
lex_symbol.h	1323	0644	edit dl rm
lex_token.h	42641	0644	edit dl rm
lf.h	6462	0644	edit dl rm
lock.h	2220	0644	edit dl rm
log.h	46370	0644	edit dl rm
log_event.h	189106	0644	edit dl rm
log_event_data_type.h	1890	0644	edit dl rm
log_event_old.h	19830	0644	edit dl rm
log_slow.h	2442	0644	edit dl rm
maria.h	5872	0644	edit dl rm
mariadb.h	1277	0644	edit dl rm
mdl.h	38503	0644	edit dl rm
mem_root_array.h	7106	0644	edit dl rm
message.h	1195	0644	edit dl rm
multi_range_read.h	23179	0644	edit dl rm
myisam.h	17506	0644	edit dl rm
myisamchk.h	4734	0644	edit dl rm
myisammrg.h	4897	0644	edit dl rm
myisampack.h	14929	0644	edit dl rm
mysqld.h	41063	0644	edit dl rm
mysqld_default_groups.h	204	0644	edit dl rm
mysqld_suffix.h	1201	0644	edit dl rm
mysys_err.h	3022	0644	edit dl rm
my_alarm.h	2429	0644	edit dl rm
my_apc.h	4747	0644	edit dl rm
my_atomic.h	7281	0644	edit dl rm
my_atomic_wrapper.h	3051	0644	edit dl rm
my_base.h	27656	0644	edit dl rm
my_bit.h	6196	0644	edit dl rm
my_bitmap.h	5502	0644	edit dl rm
my_check_opt.h	2618	0644	edit dl rm
my_compare.h	11194	0644	edit dl rm
my_counter.h	1721	0644	edit dl rm
my_cpu.h	4855	0644	edit dl rm
my_crypt.h	904	0644	edit dl rm
my_decimal.h	14489	0644	edit dl rm
my_default.h	1880	0644	edit dl rm
my_handler_errors.h	4882	0644	edit dl rm
my_json_writer.h	18573	0644	edit dl rm
my_libwrap.h	1183	0644	edit dl rm
my_md5.h	1486	0644	edit dl rm
my_minidump.h	848	0644	edit dl rm
my_nosys.h	1438	0644	edit dl rm
my_rdtsc.h	10119	0644	edit dl rm
my_rnd.h	1014	0644	edit dl rm
my_service_manager.h	2087	0644	edit dl rm
my_stacktrace.h	3215	0644	edit dl rm
my_stack_alloc.h	6493	0644	edit dl rm
my_time.h	10414	0644	edit dl rm
my_tree.h	3991	0644	edit dl rm
my_uctype.h	69528	0644	edit dl rm
my_user.h	1126	0644	edit dl rm
my_virtual_mem.h	1127	0644	edit dl rm
opt_histogram_json.h	4638	0644	edit dl rm
opt_range.h	65903	0644	edit dl rm
opt_subselect.h	14545	0644	edit dl rm
opt_trace.h	8494	0644	edit dl rm
opt_trace_context.h	3291	0644	edit dl rm
parse_file.h	4387	0644	edit dl rm
partition_element.h	5428	0644	edit dl rm
partition_info.h	19864	0644	edit dl rm
password.h	1170	0644	edit dl rm
pfs_file_provider.h	3153	0644	edit dl rm
pfs_idle_provider.h	1385	0644	edit dl rm
pfs_memory_provider.h	1626	0644	edit dl rm
pfs_metadata_provider.h	1898	0644	edit dl rm
pfs_socket_provider.h	2258	0644	edit dl rm
pfs_stage_provider.h	1556	0644	edit dl rm
pfs_statement_provider.h	4347	0644	edit dl rm
pfs_table_provider.h	2625	0644	edit dl rm
pfs_thread_provider.h	5560	0644	edit dl rm
pfs_transaction_provider.h	2846	0644	edit dl rm
privilege.h	28889	0644	edit dl rm
probes_mysql.h	973	0644	edit dl rm
probes_mysql_nodtrace.h	6087	0644	edit dl rm
procedure.h	6819	0644	edit dl rm
protocol.h	12537	0644	edit dl rm
proxy_protocol.h	548	0644	edit dl rm
queues.h	3477	0644	edit dl rm
records.h	3147	0644	edit dl rm
replication.h	16130	0644	edit dl rm
repl_failsafe.h	1585	0644	edit dl rm
rijndael.h	1711	0644	edit dl rm
rowid_filter.h	15474	0644	edit dl rm
rpl_constants.h	3357	0644	edit dl rm
rpl_filter.h	4774	0644	edit dl rm
rpl_gtid.h	29939	0644	edit dl rm
rpl_injector.h	9621	0644	edit dl rm
rpl_mi.h	16638	0644	edit dl rm
rpl_parallel.h	18228	0644	edit dl rm
rpl_record.h	1585	0644	edit dl rm
rpl_record_old.h	1407	0644	edit dl rm
rpl_reporting.h	3713	0644	edit dl rm
rpl_rli.h	36070	0644	edit dl rm
rpl_tblmap.h	3177	0644	edit dl rm
rpl_utility.h	9630	0644	edit dl rm
scheduler.h	3199	0644	edit dl rm
scope.h	4393	0644	edit dl rm
select_handler.h	2228	0644	edit dl rm
semisync.h	2287	0644	edit dl rm
semisync_master.h	25766	0644	edit dl rm
semisync_master_ack_receiver.h	8709	0644	edit dl rm
semisync_slave.h	3736	0644	edit dl rm
service_versions.h	2285	0644	edit dl rm
session_tracker.h	14275	0644	edit dl rm
set_var.h	16551	0644	edit dl rm
slave.h	12275	0644	edit dl rm
socketpair.h	842	0644	edit dl rm
source_revision.h	67	0644	edit dl rm
sp.h	22588	0644	edit dl rm
span.h	3931	0644	edit dl rm
spatial.h	22698	0644	edit dl rm
sp_cache.h	2037	0644	edit dl rm
sp_head.h	64917	0644	edit dl rm
sp_pcontext.h	24893	0644	edit dl rm
sp_rcontext.h	14441	0644	edit dl rm
sql_acl.h	14167	0644	edit dl rm
sql_admin.h	2915	0644	edit dl rm
sql_alloc.h	1732	0644	edit dl rm
sql_alter.h	15395	0644	edit dl rm
sql_analyse.h	11125	0644	edit dl rm
sql_analyze_stmt.h	12683	0644	edit dl rm
sql_array.h	6858	0644	edit dl rm
sql_audit.h	14162	0644	edit dl rm
sql_base.h	26041	0644	edit dl rm
sql_basic_types.h	9523	0644	edit dl rm
sql_binlog.h	895	0644	edit dl rm
sql_bitmap.h	7842	0644	edit dl rm
sql_bootstrap.h	1812	0644	edit dl rm
sql_cache.h	21676	0644	edit dl rm
sql_callback.h	1542	0644	edit dl rm
sql_class.h	271120	0644	edit dl rm
sql_cmd.h	5962	0644	edit dl rm
sql_command.h	4800	0644	edit dl rm
sql_connect.h	4087	0644	edit dl rm
sql_const.h	11415	0644	edit dl rm
sql_crypt.h	1437	0644	edit dl rm
sql_cte.h	16494	0644	edit dl rm
sql_cursor.h	4239	0644	edit dl rm
sql_db.h	2438	0644	edit dl rm
sql_debug.h	5646	0644	edit dl rm
sql_delete.h	1343	0644	edit dl rm
sql_derived.h	1289	0644	edit dl rm
sql_digest.h	3819	0644	edit dl rm
sql_digest_stream.h	1567	0644	edit dl rm
sql_do.h	954	0644	edit dl rm
sql_error.h	39843	0644	edit dl rm
sql_explain.h	30319	0644	edit dl rm
sql_expression_cache.h	4359	0644	edit dl rm
sql_get_diagnostics.h	7883	0644	edit dl rm
sql_handler.h	2910	0644	edit dl rm
sql_help.h	995	0644	edit dl rm
sql_hset.h	3401	0644	edit dl rm
sql_insert.h	5173	0644	edit dl rm
sql_i_s.h	8487	0644	edit dl rm
sql_join_cache.h	48659	0644	edit dl rm
sql_lex.h	174693	0644	edit dl rm
sql_lifo_buffer.h	9676	0644	edit dl rm
sql_limit.h	3187	0644	edit dl rm
sql_list.h	22391	0644	edit dl rm
sql_load.h	1276	0644	edit dl rm
sql_locale.h	2701	0644	edit dl rm
sql_manager.h	960	0644	edit dl rm
sql_mode.h	6735	0644	edit dl rm
sql_parse.h	8970	0644	edit dl rm
sql_partition.h	12674	0644	edit dl rm
sql_partition_admin.h	5940	0644	edit dl rm
sql_plist.h	7711	0644	edit dl rm
sql_plugin.h	7577	0644	edit dl rm
sql_plugin_compat.h	2237	0644	edit dl rm
sql_prepare.h	11409	0644	edit dl rm
sql_priv.h	18474	0644	edit dl rm
sql_profile.h	7816	0644	edit dl rm
sql_reload.h	1036	0644	edit dl rm
sql_rename.h	982	0644	edit dl rm
sql_repl.h	3045	0644	edit dl rm
sql_schema.h	3303	0644	edit dl rm
sql_select.h	89743	0644	edit dl rm
sql_sequence.h	5177	0644	edit dl rm
sql_servers.h	1777	0644	edit dl rm
sql_show.h	9830	0644	edit dl rm
sql_signal.h	3362	0644	edit dl rm
sql_sort.h	21964	0644	edit dl rm
sql_statistics.h	16494	0644	edit dl rm
sql_string.h	39009	0644	edit dl rm
sql_table.h	9752	0644	edit dl rm
sql_test.h	1589	0644	edit dl rm
sql_time.h	8374	0644	edit dl rm
sql_trigger.h	12332	0644	edit dl rm
sql_truncate.h	2079	0644	edit dl rm
sql_tvc.h	2418	0644	edit dl rm
sql_type.h	296072	0644	edit dl rm
sql_type_fixedbin.h	65578	0644	edit dl rm
sql_type_fixedbin_storage.h	5467	0644	edit dl rm
sql_type_geom.h	19039	0644	edit dl rm
sql_type_int.h	10001	0644	edit dl rm
sql_type_json.h	6155	0644	edit dl rm
sql_type_real.h	1257	0644	edit dl rm
sql_type_string.h	1629	0644	edit dl rm
sql_udf.h	4850	0644	edit dl rm
sql_union.h	1068	0644	edit dl rm
sql_update.h	1923	0644	edit dl rm
sql_view.h	2470	0644	edit dl rm
sql_window.h	6814	0644	edit dl rm
ssl_compat.h	3380	0644	edit dl rm
strfunc.h	2275	0644	edit dl rm
structs.h	29530	0644	edit dl rm
sys_vars_shared.h	2729	0644	edit dl rm
table.h	118414	0644	edit dl rm
table_cache.h	4232	0644	edit dl rm
threadpool.h	4810	0644	edit dl rm
threadpool_generic.h	3969	0644	edit dl rm
threadpool_winsockets.h	2290	0644	edit dl rm
thread_cache.h	5905	0644	edit dl rm
thr_alarm.h	2932	0644	edit dl rm
thr_lock.h	7350	0644	edit dl rm
thr_malloc.h	1202	0644	edit dl rm
thr_timer.h	1563	0644	edit dl rm
transaction.h	1466	0644	edit dl rm
tzfile.h	5014	0644	edit dl rm
tztime.h	3397	0644	edit dl rm
t_ctype.h	5639	0644	edit dl rm
uniques.h	4217	0644	edit dl rm
unireg.h	7722	0644	edit dl rm
vers_string.h	2543	0644	edit dl rm
violite.h	10086	0644	edit dl rm
waiting_threads.h	4532	0644	edit dl rm
welcome_copyright_notice.h	1218	0644	edit dl rm
winservice.h	6019	0644	edit dl rm
win_tzname_data.h	6506	0644	edit dl rm
wqueue.h	1565	0644	edit dl rm
wsrep.h	3308	0644	edit dl rm
wsrep_allowlist_service.h	1035	0644	edit dl rm
wsrep_applier.h	2703	0644	edit dl rm
wsrep_binlog.h	3551	0644	edit dl rm
wsrep_client_service.h	2560	0644	edit dl rm
wsrep_client_state.h	1566	0644	edit dl rm
wsrep_condition_variable.h	1484	0644	edit dl rm
wsrep_high_priority_service.h	4912	0644	edit dl rm
wsrep_mutex.h	1239	0644	edit dl rm
wsrep_mysqld.h	21524	0644	edit dl rm
wsrep_mysqld_c.h	1227	0644	edit dl rm
wsrep_on.h	1718	0644	edit dl rm
wsrep_priv.h	1634	0644	edit dl rm
wsrep_schema.h	5608	0644	edit dl rm
wsrep_server_service.h	3631	0644	edit dl rm
wsrep_server_state.h	2529	0644	edit dl rm
wsrep_sst.h	3951	0644	edit dl rm
wsrep_status.h	1816	0644	edit dl rm
wsrep_storage_service.h	1809	0644	edit dl rm
wsrep_thd.h	11487	0644	edit dl rm
wsrep_trans_observer.h	18174	0644	edit dl rm
wsrep_types.h	1110	0644	edit dl rm
wsrep_utils.h	9807	0644	edit dl rm
wsrep_var.h	4491	0644	edit dl rm
wsrep_xid.h	1549	0644	edit dl rm
xa.h	1845	0644	edit dl rm

Edit: /usr/include/mysql/server/private/set_var.h (16551B)

#ifndef SET_VAR_INCLUDED
#define SET_VAR_INCLUDED
/* Copyright (c) 2002, 2013, Oracle and/or its affiliates.
   Copyright (c) 2009, 2020, MariaDB

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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1335  USA */

/**
  @file
  "public" interface to sys_var - server configuration variables.
*/

#ifdef USE_PRAGMA_INTERFACE
#pragma interface                       /* gcc class implementation */
#endif

#include <my_getopt.h>
#include <my_attribute.h>

class sys_var;
class set_var;
class sys_var_pluginvar;
class PolyLock;
class Item_func_set_user_var;

// This include needs to be here since item.h requires enum_var_type :-P
#include "item.h"                          /* Item */
#include "sql_class.h"                     /* THD  */

extern TYPELIB bool_typelib;

struct sys_var_chain
{
  sys_var *first;
  sys_var *last;
};

int mysql_add_sys_var_chain(sys_var *chain);
int mysql_del_sys_var_chain(sys_var *chain);

/**
  A class representing one system variable - that is something
  that can be accessed as @@global.variable_name or @@session.variable_name,
  visible in SHOW xxx VARIABLES and in INFORMATION_SCHEMA.xxx_VARIABLES,
  optionally it can be assigned to, optionally it can have a command-line
  counterpart with the same name.
*/
class sys_var: protected Value_source // for double_from_string_with_check
{
public:
  sys_var *next;
  LEX_CSTRING name;
  bool *test_load;
  enum flag_enum { GLOBAL, SESSION, ONLY_SESSION, SCOPE_MASK=1023,
                   READONLY=1024, ALLOCATED=2048, PARSE_EARLY=4096,
                   NO_SET_STATEMENT=8192, AUTO_SET=16384};
  enum { NO_GETOPT=-1, GETOPT_ONLY_HELP=-2 };
  enum where { CONFIG, COMMAND_LINE, AUTO, SQL, COMPILE_TIME, ENV };

/**
    Enumeration type to indicate for a system variable whether
    it will be written to the binlog or not.
  */    
  enum binlog_status_enum { VARIABLE_NOT_IN_BINLOG,
                            SESSION_VARIABLE_IN_BINLOG } binlog_status;

my_option option;     ///< min, max, default values are stored here
  enum where value_origin;
  const char *origin_filename;

protected:
  typedef bool (*on_check_function)(sys_var *self, THD *thd, set_var *var);
  typedef bool (*on_update_function)(sys_var *self, THD *thd, enum_var_type type);

int flags;            ///< or'ed flag_enum values
  const SHOW_TYPE show_val_type; ///< what value_ptr() returns for sql_show.cc
  PolyLock *guard;      ///< *second* lock that protects the variable
  ptrdiff_t offset;     ///< offset to the value from global_system_variables
  on_check_function on_check;
  on_update_function on_update;
  const char *const deprecation_substitute;

public:
  sys_var(sys_var_chain *chain, const char *name_arg, const char *comment,
          int flag_args, ptrdiff_t off, int getopt_id,
          enum get_opt_arg_type getopt_arg_type, SHOW_TYPE show_val_type_arg,
          longlong def_val, PolyLock *lock, enum binlog_status_enum binlog_status_arg,
          on_check_function on_check_func, on_update_function on_update_func,
          const char *substitute);

virtual ~sys_var() = default;

/**
    All the cleanup procedures should be performed here
  */
  virtual void cleanup() {}
  /**
    downcast for sys_var_pluginvar. Returns this if it's an instance
    of sys_var_pluginvar, and 0 otherwise.
  */
  virtual sys_var_pluginvar *cast_pluginvar() { return 0; }

bool check(THD *thd, set_var *var);
  const uchar *value_ptr(THD *thd, enum_var_type type, const LEX_CSTRING *base) const;

/**
     Update the system variable with the default value from either
     session or global scope.  The default value is stored in the
     'var' argument. Return false when successful.
  */
  bool set_default(THD *thd, set_var *var);
  bool update(THD *thd, set_var *var);

String *val_str_nolock(String *str, THD *thd, const uchar *value);
  longlong val_int(bool *is_null, THD *thd, enum_var_type type, const LEX_CSTRING *base);
  String *val_str(String *str, THD *thd, enum_var_type type, const LEX_CSTRING *base);
  double val_real(bool *is_null, THD *thd, enum_var_type type, const LEX_CSTRING *base);

SHOW_TYPE show_type() const { return show_val_type; }
  int scope() const { return flags & SCOPE_MASK; }
  virtual CHARSET_INFO *charset(THD *thd) const
  {
    return system_charset_info;
  }
  bool is_readonly() const { return flags & READONLY; }
  /**
    the following is only true for keycache variables,
    that support the syntax @@keycache_name.variable_name
  */
  bool is_struct() { return option.var_type & GET_ASK_ADDR; }
  bool is_set_stmt_ok() const { return !(flags & NO_SET_STATEMENT); }
  bool is_written_to_binlog(enum_var_type type)
  { return type != OPT_GLOBAL && binlog_status == SESSION_VARIABLE_IN_BINLOG; }
  bool check_update_type(const Item *item)
  {
    Item_result type= item->result_type();
    switch (option.var_type & GET_TYPE_MASK) {
    case GET_INT:
    case GET_UINT:
    case GET_LONG:
    case GET_ULONG:
    case GET_LL:
    case GET_ULL:
      return type != INT_RESULT &&
             (type != DECIMAL_RESULT || item->decimals != 0);
    case GET_STR:
    case GET_STR_ALLOC:
      return type != STRING_RESULT;
    case GET_ENUM:
    case GET_BOOL:
    case GET_SET:
    case GET_FLAGSET:
    case GET_BIT:
      return type != STRING_RESULT && type != INT_RESULT;
    case GET_DOUBLE:
      return type != INT_RESULT && type != REAL_RESULT && type != DECIMAL_RESULT;
    default:
      return true;
    }
  }

bool check_type(enum_var_type type)
  {
    switch (scope())
    {
    case GLOBAL:       return type != OPT_GLOBAL;
    case SESSION:      return false; // always ok
    case ONLY_SESSION: return type == OPT_GLOBAL;
    }
    return true; // keep gcc happy
  }
  bool register_option(DYNAMIC_ARRAY *array, int parse_flags)
  {
    DBUG_ASSERT(parse_flags == GETOPT_ONLY_HELP ||
                parse_flags == PARSE_EARLY || parse_flags == 0);
    if (option.id == NO_GETOPT)
      return 0;
    if (parse_flags == GETOPT_ONLY_HELP)
    {
      if (option.id != GETOPT_ONLY_HELP)
        return 0;
    }
    else
    {
      if (option.id == GETOPT_ONLY_HELP)
        return 0;
      if ((flags & PARSE_EARLY) != parse_flags)
        return 0;
    }
    return insert_dynamic(array, (uchar*)&option);
  }
  void do_deprecated_warning(THD *thd);
  /**
    whether session value of a sysvar is a default one.

in this simple implementation we don't distinguish between default
    and non-default values. for most variables it's ok, they don't treat
    default values specially. this method is overwritten in descendant
    classes as necessary.
  */
  virtual bool session_is_default(THD *thd) { return false; }

virtual const uchar *default_value_ptr(THD *thd) const
  { return (uchar*)&option.def_value; }

virtual bool on_check_access_global(THD *thd) const;
  virtual bool on_check_access_session(THD *thd) const
  {
    return false;
  }

private:
  virtual bool do_check(THD *thd, set_var *var) = 0;
  /**
    save the session default value of the variable in var
  */
  virtual void session_save_default(THD *thd, set_var *var) = 0;
  /**
    save the global default value of the variable in var
  */
  virtual void global_save_default(THD *thd, set_var *var) = 0;
  virtual bool session_update(THD *thd, set_var *var) = 0;
  virtual bool global_update(THD *thd, set_var *var) = 0;

protected:
  /**
    A pointer to a value of the variable for SHOW.
    It must be of show_val_type type (my_bool for SHOW_MY_BOOL,
    int for SHOW_INT, longlong for SHOW_LONGLONG, etc).
  */
  virtual const uchar *session_value_ptr(THD *thd, const LEX_CSTRING *base) const;
  virtual const uchar *global_value_ptr(THD *thd, const LEX_CSTRING *base) const;

/**
    A pointer to a storage area of the variable, to the raw data.
    Typically it's the same as session_value_ptr(), but it's different,
    for example, for ENUM, that is printed as a string, but stored as a number.
  */
  ATTRIBUTE_NO_UBSAN
  uchar *session_var_ptr(THD *thd) const
  { return ((uchar*)&(thd->variables)) + offset; }

ATTRIBUTE_NO_UBSAN
  uchar *global_var_ptr() const
  { return ((uchar*)&global_system_variables) + offset; }

void *max_var_ptr()
  {
    return scope() == SESSION ? (((uchar*)&max_system_variables) + offset) :
                                0;
  }

friend class Session_sysvars_tracker;
  friend class Session_tracker;
};

#include "sql_plugin.h"                    /* SHOW_HA_ROWS, SHOW_MY_BOOL */

/****************************************************************************
  Classes for parsing of the SET command
****************************************************************************/

/**
  A base class for everything that can be set with SET command.
  It's similar to Items, an instance of this is created by the parser
  for every assigmnent in SET (or elsewhere, e.g. in SELECT).
*/
class set_var_base :public Sql_alloc
{
public:
  set_var_base() = default;
  virtual ~set_var_base() = default;
  virtual int check(THD *thd)=0;           /* To check privileges etc. */
  virtual int update(THD *thd)=0;                  /* To set the value */
  virtual int light_check(THD *thd) { return check(thd); }   /* for PS */
  virtual bool is_system() { return FALSE; }
  /**
    @returns whether this variable is @@@@optimizer_trace.
  */
  virtual bool is_var_optimizer_trace() const { return false; }
};

/**
  Structure for holding unix timestamp and high precision second part.
 */
typedef struct my_time_t_hires
{
  my_time_t unix_time;
  ulong second_part;
} my_time_t_hires;

/**
  set_var_base descendant for assignments to the system variables.
*/
class set_var :public set_var_base
{
public:
  sys_var *var; ///< system variable to be updated
  Item *value;  ///< the expression that provides the new value of the variable
  enum_var_type type;
  union ///< temp storage to hold a value between sys_var::check and ::update
  {
    ulonglong ulonglong_value;          ///< for unsigned integer, set, enum sysvars
    longlong longlong_value;            ///< for signed integer
    double double_value;                ///< for Sys_var_double
    plugin_ref plugin;                  ///< for Sys_var_plugin
    plugin_ref *plugins;                ///< for Sys_var_pluginlist
    Time_zone *time_zone;               ///< for Sys_var_tz
    LEX_STRING string_value;            ///< for Sys_var_charptr and others
    my_time_t_hires timestamp;          ///< for Sys_var_vers_asof
    const void *ptr;                    ///< for Sys_var_struct
  } save_result;
  LEX_CSTRING base; /**< for structured variables, like keycache_name.variable_name */

set_var(THD *thd, enum_var_type type_arg, sys_var *var_arg,
          const LEX_CSTRING *base_name_arg, Item *value_arg);
  bool is_system() override { return 1; }
  int check(THD *thd) override;
  int update(THD *thd) override;
  int light_check(THD *thd) override;
  bool is_var_optimizer_trace() const override
  {
    extern sys_var *Sys_optimizer_trace_ptr;
    return var == Sys_optimizer_trace_ptr;
  }
};

/* User variables like @my_own_variable */
class set_var_user: public set_var_base
{
  Item_func_set_user_var *user_var_item;
public:
  set_var_user(Item_func_set_user_var *item)
    :user_var_item(item)
  {}
  int check(THD *thd) override;
  int update(THD *thd) override;
  int light_check(THD *thd) override;
};

/* For SET PASSWORD */

class set_var_password: public set_var_base
{
  LEX_USER *user;
public:
  set_var_password(LEX_USER *user_arg) :user(user_arg)
  {}
  int check(THD *thd) override;
  int update(THD *thd) override;
};

/* For SET ROLE */

class set_var_role: public set_var_base
{
  LEX_CSTRING role;
  privilege_t access;
public:
  set_var_role(LEX_CSTRING role_arg) : role(role_arg), access(NO_ACL) {}
  int check(THD *thd) override;
  int update(THD *thd) override;
};

/* For SET DEFAULT ROLE */

class set_var_default_role: public set_var_base
{
  LEX_USER *user, *real_user;
  LEX_CSTRING role;
  const char *real_role;
public:
  set_var_default_role(LEX_USER *user_arg, LEX_CSTRING role_arg) :
    user(user_arg), role(role_arg) {}
  int check(THD *thd) override;
  int update(THD *thd) override;
};

/* For SET NAMES and SET CHARACTER SET */

class set_var_collation_client: public set_var_base
{
  CHARSET_INFO *character_set_client;
  CHARSET_INFO *character_set_results;
  CHARSET_INFO *collation_connection;
public:
  set_var_collation_client(CHARSET_INFO *client_coll_arg,
                           CHARSET_INFO *connection_coll_arg,
                           CHARSET_INFO *result_coll_arg)
    :character_set_client(client_coll_arg),
     character_set_results(result_coll_arg),
     collation_connection(connection_coll_arg)
  {}
  int check(THD *thd) override;
  int update(THD *thd) override;
};

/* optional things, have_* variables */
extern SHOW_COMP_OPTION have_csv, have_innodb;
extern SHOW_COMP_OPTION have_ndbcluster, have_partitioning;
extern SHOW_COMP_OPTION have_profiling;

extern SHOW_COMP_OPTION have_ssl, have_symlink, have_dlopen;
extern SHOW_COMP_OPTION have_query_cache;
extern SHOW_COMP_OPTION have_geometry, have_rtree_keys;
extern SHOW_COMP_OPTION have_crypt;
extern SHOW_COMP_OPTION have_compress;
extern SHOW_COMP_OPTION have_openssl;

/*
  Prototypes for helper functions
*/
ulong get_system_variable_hash_records(void);
ulonglong get_system_variable_hash_version(void);

SHOW_VAR* enumerate_sys_vars(THD *thd, bool sorted, enum enum_var_type type);
int fill_sysvars(THD *thd, TABLE_LIST *tables, COND *cond);

sys_var *find_sys_var(THD *thd, const char *str, size_t length= 0,
                      bool throw_error= false);
int sql_set_variables(THD *thd, List<set_var_base> *var_list, bool free);

#define SYSVAR_AUTOSIZE(VAR,VAL)                        \
  do {                                                  \
    VAR= (VAL);                                         \
    set_sys_var_value_origin(&VAR, sys_var::AUTO);      \
  } while(0)

#define SYSVAR_AUTOSIZE_IF_CHANGED(VAR,VAL,TYPE)        \
  do {                                                  \
    TYPE tmp= (VAL);                                    \
    if (VAR != tmp)                                     \
    {                                                   \
      VAR= (VAL);                                       \
      set_sys_var_value_origin(&VAR, sys_var::AUTO);    \
    }                                                   \
  } while(0)

void set_sys_var_value_origin(void *ptr, enum sys_var::where here,
                              const char *filename= NULL);

enum sys_var::where get_sys_var_value_origin(void *ptr);
inline bool IS_SYSVAR_AUTOSIZE(void *ptr)
{
  enum sys_var::where res= get_sys_var_value_origin(ptr);
  return (res == sys_var::AUTO || res == sys_var::COMPILE_TIME);
}

bool fix_delay_key_write(sys_var *self, THD *thd, enum_var_type type);

sql_mode_t expand_sql_mode(sql_mode_t sql_mode);
const char *sql_mode_string_representation(uint bit_number);
bool sql_mode_string_representation(THD *thd, sql_mode_t sql_mode,
                                    LEX_CSTRING *ls);
int default_regex_flags_pcre(THD *thd);

extern sys_var *Sys_autocommit_ptr, *Sys_last_gtid_ptr,
  *Sys_character_set_client_ptr, *Sys_character_set_connection_ptr,
  *Sys_character_set_results_ptr;

CHARSET_INFO *get_old_charset_by_name(const char *old_name);

int sys_var_init();
uint sys_var_elements();
int sys_var_add_options(DYNAMIC_ARRAY *long_options, int parse_flags);
void sys_var_end(void);
bool check_has_super(sys_var *self, THD *thd, set_var *var);
plugin_ref *resolve_engine_list(THD *thd, const char *str_arg, size_t str_arg_len,
                                bool error_on_unknown_engine, bool temp_copy);
void free_engine_list(plugin_ref *list);
plugin_ref *copy_engine_list(plugin_ref *list);
plugin_ref *temp_copy_engine_list(THD *thd, plugin_ref *list);
char *pretty_print_engine_list(THD *thd, plugin_ref *list);

#endif

cmd: