A variant of enum where: More...

#include <sys_vars.h>

Inheritance diagram for Sys_var_multi_enum:

Classes
struct	ALIAS

Public Member Functions
	Sys_var_multi_enum (const char name_arg, const char comment, int flag_args, ptrdiff_t off, size_t size, CMD_LINE getopt, const ALIAS aliases_arg[], uint value_count_arg, uint def_val, uint command_line_no_value_arg, PolyLock lock=nullptr, enum binlog_status_enum binlog_status_arg=VARIABLE_NOT_IN_BINLOG, on_check_function on_check_func=nullptr, on_update_function on_update_func=nullptr, const char substitute=nullptr, int parse_flag=PARSE_NORMAL)
	Enumerated type system variable. More...

int	find_value (const char *text)
	Return the numeric value for a given alias string, or -1 if the string is not a valid alias. More...

const char *	fixup_command_line (const char *value_str)
	Because of limitations in the command-line parsing library, the value given on the command-line cannot be automatically copied to the global value. More...

bool	do_check (THD , set_var var) override

bool	check_update_type (Item_result type) override

bool	session_update (THD , set_var ) override

bool	global_update (THD , set_var ) override

void	session_save_default (THD , set_var ) override
	save the session default value of the variable in var More...

void	global_save_default (THD , set_var var) override
	save the global default value of the variable in var More...

void	saved_value_to_string (THD , set_var var, char *def_val) override
	This function converts value stored in save_result to string. More...

const uchar *	session_value_ptr (THD , THD , std::string_view) override
	A pointer to a value of the variable for SHOW. More...

const uchar *	global_value_ptr (THD *, std::string_view) override

Public Member Functions inherited from sys_var
	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, int parse_flag, sys_var persisted_alias=nullptr, bool is_persisted_deprecated=false)
	sys_var constructor More...

virtual	~sys_var ()=default

const char *	get_deprecation_substitute ()

virtual void	cleanup ()
	All the cleanup procedures should be performed here. More...

virtual sys_var_pluginvar *	cast_pluginvar ()
	downcast for sys_var_pluginvar. More...

bool	check (THD thd, set_var var)

const uchar *	value_ptr (THD running_thd, THD target_thd, enum_var_type type, std::string_view keycache_name)

const uchar *	value_ptr (THD *thd, enum_var_type type, std::string_view keycache_name)

virtual void	update_default (longlong new_def_value)

virtual longlong	get_default ()

virtual longlong	get_min_value ()

virtual ulonglong	get_max_value ()

virtual ulong	get_var_type ()
	Returns variable type. More...

virtual void	set_arg_source (get_opt_arg_source *)

virtual void	set_is_plugin (bool)

virtual enum_variable_source	get_source ()

virtual const char *	get_source_name ()

virtual void	set_source (enum_variable_source src)

virtual bool	set_source_name (const char *path)

virtual bool	set_user (const char *usr)

virtual const char *	get_user ()

virtual const char *	get_host ()

virtual bool	set_host (const char *hst)

virtual ulonglong	get_timestamp () const

virtual void	set_user_host (THD *thd)

my_option *	get_option ()

virtual void	set_timestamp ()

virtual void	set_timestamp (ulonglong ts)

virtual bool	is_non_persistent ()

bool	set_default (THD thd, set_var var)
	Update the system variable with the default value from either session or global scope. More...

bool	update (THD thd, set_var var)

SHOW_TYPE	show_type ()

int	scope () const

const CHARSET_INFO *	charset (THD *thd)

bool	is_readonly () const

bool	not_visible () const

bool	is_trilevel () const

bool	is_persist_readonly () const

bool	is_parse_early () const

bool	is_sensitive () const

bool	is_hint_updateable () const
	Check if the variable can be set using SET_VAR hint. More...

bool	is_struct ()
	the following is only true for keycache variables, that support the syntax @keycache_name.variable_name More...

bool	is_written_to_binlog (enum_var_type type)

bool	check_scope (enum_var_type query_type)
	Return true for success if: Global query and variable scope is GLOBAL or SESSION, or Session query and variable scope is SESSION or ONLY_SESSION. More...

bool	is_global_persist (enum_var_type type)

bool	is_settable_at_command_line ()
	Return true if settable at the command line. More...

bool	register_option (std::vector< my_option > *array, int parse_flags)

void	do_deprecated_warning (THD *thd)

Item *	copy_value (THD *thd)
	Create item from system variable value. More...

void	save_default (THD thd, set_var var)

bool	check_if_sensitive_in_context (THD *, bool suppress_errors=true) const

Private Attributes
const uint	value_count
	The number of allowed numeric values. More...

const ALIAS *	aliases
	Array of all textual aliases. More...

uint	alias_count
	The number of elements of aliases (computed in the constructor). More...

const char *	command_line_value
	Pointer to the value set by the command line (set by the command line parser, copied to the global value in fixup_command_line()). More...

uint	command_line_no_value

Additional Inherited Members
Public Types inherited from sys_var
enum	flag_enum { GLOBAL = 0x0001 , SESSION = 0x0002 , ONLY_SESSION = 0x0004 , SCOPE_MASK = 0x03FF , READONLY = 0x0400 , ALLOCATED = 0x0800 , INVISIBLE = 0x1000 , TRI_LEVEL = 0x2000 , NOTPERSIST = 0x4000 , HINT_UPDATEABLE = 0x8000 , PERSIST_AS_READ_ONLY = 0x10000 , SENSITIVE = 0x20000 }

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

Public Attributes inherited from sys_var
sys_var *	next

LEX_CSTRING	name

sys_var *	m_persisted_alias
	If the variable has an alias in the persisted variables file, this should point to it. More...

bool	m_is_persisted_deprecated
	If m_persist_alias is set, and the current variable is deprecated and m_persist_alias is the recommended substitute, then this flag should be set to true. More...

enum sys_var::binlog_status_enum	binlog_status

Static Public Attributes inherited from sys_var
static const int	PARSE_EARLY = 1

static const int	PARSE_NORMAL = 2

Protected Types inherited from sys_var
typedef bool(*	on_check_function) (sys_var self, THD thd, set_var *var)

typedef bool(*	pre_update_function) (sys_var self, THD thd, set_var *var)

typedef bool(*	on_update_function) (sys_var self, THD thd, enum_var_type type)

Protected Member Functions inherited from sys_var
uchar *	session_var_ptr (THD *thd)
	A pointer to a storage area of the variable, to the raw data. More...

uchar *	global_var_ptr ()

Protected Attributes inherited from sys_var
int	flags
	or'ed flag_enum values More...

int	m_parse_flag
	either PARSE_EARLY or PARSE_NORMAL. More...

const SHOW_TYPE	show_val_type
	what value_ptr() returns for sql_show.cc More...

my_option	option
	min, max, default values are stored here More...

PolyLock *	guard
	second lock that protects the variable More...

ptrdiff_t	offset
	offset to the value from global_system_variables More...

on_check_function	on_check

pre_update_function	pre_update
	Pointer to function to be invoked before updating system variable (but after calling on_check hook), while we do not hold any locks yet. More...

on_update_function	on_update

const char *const	deprecation_substitute

bool	is_os_charset
	true if the value is in character_set_filesystem More...

struct get_opt_arg_source	source

char	user [USERNAME_CHAR_LENGTH+1]

char	host [HOSTNAME_LENGTH+1]

ulonglong	timestamp

Detailed Description

A variant of enum where:

Each value may have multiple enum-like aliases.
Instances of the class can specify different default values for the cases:
- User specifies the command-line option without a value (i.e., –option, not –option=value).
- User does not specify a command-line option at all.

This exists mainly to allow extending a variable that once was boolean in a GA version, into an enumeration type. Booleans accept multiple aliases (0=off=false, 1=on=true), but Sys_var_enum does not, so we could not use Sys_var_enum without breaking backward compatibility. Moreover, booleans default to false if option is not given, and true if option is given without value.

This is incompatible with boolean in the following sense: 'SELECT @variable' returns 0 or 1 for a boolean, whereas this class (similar to enum) returns the textual form. (Note that both boolean, enum, and this class return the textual form in SHOW VARIABLES and SELECT * FROM information_schema.variables).

See enforce_gtid_consistency for an example of how this can be used.

Constructor & Destructor Documentation

◆ Sys_var_multi_enum()

Sys_var_multi_enum::Sys_var_multi_enum	(	const char *	name_arg,
		const char *	comment,
		int	flag_args,
		ptrdiff_t	off,
		size_t	size,
		CMD_LINE	getopt,
		const ALIAS	aliases_arg[],
		uint	value_count_arg,
		uint	def_val,
		uint	command_line_no_value_arg,
		PolyLock *	lock = `nullptr`,
		enum binlog_status_enum	binlog_status_arg = `VARIABLE_NOT_IN_BINLOG`,
		on_check_function	on_check_func = `nullptr`,
		on_update_function	on_update_func = `nullptr`,
		const char *	substitute = `nullptr`,
		int	parse_flag = `PARSE_NORMAL`
	)

inline

Enumerated type system variable.

Parameters

name_arg	See sys_var::sys_var()
comment	See sys_var::sys_var()
flag_args	See sys_var::sys_var()
off	See sys_var::sys_var()
size	See sys_var::sys_var()
getopt	See sys_var::sys_var()
aliases_arg	Array of ALIASes, indicating which textual values map to which number. Should be terminated with an ALIAS having member variable alias set to NULL. The first ‘value_count_arg’ elements must map to 0, 1, etc; these will be used when the value is displayed. Remaining elements may appear in arbitrary order.
value_count_arg	The number of allowed integer values.
def_val	The default value if no command line option is given. This must be a valid index into the aliases_arg array, but it does not have to be less than value_count. The corresponding alias will be used in mysqld –help to show the default value.
command_line_no_value_arg	The default value if a command line option is given without a value ('–command-line-option' without '=VALUE'). This must be less than value_count_arg.
lock	See sys_var::sys_var()
binlog_status_arg	See sys_var::sys_var()
on_check_func	See sys_var::sys_var()
on_update_func	See sys_var::sys_var()
substitute	See sys_var::sys_var()
parse_flag	See sys_var::sys_var()

Member Function Documentation

◆ check_update_type()

bool Sys_var_multi_enum::check_update_type ( Item_result type )

inlineoverridevirtual

Implements sys_var.

◆ do_check()

bool Sys_var_multi_enum::do_check	(	THD *	,
		set_var *	var
	)

inlineoverridevirtual

Implements sys_var.

◆ find_value()

int Sys_var_multi_enum::find_value ( const char * text )

inline

Return the numeric value for a given alias string, or -1 if the string is not a valid alias.

◆ fixup_command_line()

const char * Sys_var_multi_enum::fixup_command_line ( const char * value_str )

inline

Because of limitations in the command-line parsing library, the value given on the command-line cannot be automatically copied to the global value.

Instead, inheritants of this class should call this function from mysqld.cc:mysqld_get_one_option.

Parameters

value_str Pointer to the value specified on the command line (as in –option=VALUE).

Return values

NULL	Success.
non-NULL	Pointer to the invalid string that was used as argument.

◆ global_save_default()

void Sys_var_multi_enum::global_save_default	(	THD *	thd,
		set_var *	var
	)

inlineoverridevirtual

save the global default value of the variable in var

Implements sys_var.

◆ global_update()

bool Sys_var_multi_enum::global_update	(	THD *	,
		set_var *
	)

inlineoverridevirtual

Implements sys_var.

Reimplemented in Sys_var_enforce_gtid_consistency.

◆ global_value_ptr()

const uchar * Sys_var_multi_enum::global_value_ptr	(	THD *	,
		std::string_view
	)

inlineoverridevirtual

Reimplemented from sys_var.

◆ saved_value_to_string()

void Sys_var_multi_enum::saved_value_to_string	(	THD *	thd,
		set_var *	var,
		char *	def_val
	)

inlineoverridevirtual

This function converts value stored in save_result to string.

This function must be called after calling save_default() as save_default() will store default value to save_result.

Implements sys_var.

◆ session_save_default()

void Sys_var_multi_enum::session_save_default	(	THD *	thd,
		set_var *	var
	)

inlineoverridevirtual

save the session default value of the variable in var

Implements sys_var.

◆ session_update()

bool Sys_var_multi_enum::session_update	(	THD *	,
		set_var *
	)

inlineoverridevirtual

Implements sys_var.

◆ session_value_ptr()

const uchar * Sys_var_multi_enum::session_value_ptr	(	THD *	running_thd,
		THD *	target_thd,
		std::string_view	keycache_name
	)

inlineoverridevirtual

A pointer to a value of the variable for SHOW.

It must be of show_val_type type (bool for SHOW_BOOL, int for SHOW_INT, longlong for SHOW_LONGLONG, etc).

Reimplemented from sys_var.

Member Data Documentation

◆ alias_count

uint Sys_var_multi_enum::alias_count

private

The number of elements of aliases (computed in the constructor).

◆ aliases

const ALIAS* Sys_var_multi_enum::aliases

private

Array of all textual aliases.

◆ command_line_no_value

uint Sys_var_multi_enum::command_line_no_value

private

◆ command_line_value

const char* Sys_var_multi_enum::command_line_value

private

Pointer to the value set by the command line (set by the command line parser, copied to the global value in fixup_command_line()).

◆ value_count

const uint Sys_var_multi_enum::value_count

private

The number of allowed numeric values.

The documentation for this class was generated from the following file:

sql/sys_vars.h

Classes

Public Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Sys_var_multi_enum()

Member Function Documentation

◆ check_update_type()

◆ do_check()

◆ find_value()

◆ fixup_command_line()

◆ global_save_default()

◆ global_update()

◆ global_value_ptr()

◆ saved_value_to_string()

◆ session_save_default()

◆ session_update()

◆ session_value_ptr()

Member Data Documentation

◆ alias_count

◆ aliases

◆ command_line_no_value

◆ command_line_value

◆ value_count