qep_row::mem_root_str Struct Reference

Helper class to keep string data in MEM_ROOT before passing to Item_string. More...

#include <opt_explain_format.h>

Public Member Functions
	mem_root_str ()
void	cleanup ()
bool	is_empty ()
bool	set (const char *str_arg)
bool	set (const String &s)
bool	set (const char *str_arg, size_t length_arg)
	Make a copy of the string in MEM_ROOT. More...
void	set (Lazy *x)
	Save expression for further evaluation. More...
void	set_const (const char *str_arg)
	Make a copy of string constant. More...
void	set_const (const char *str_arg, size_t length_arg)

Static Public Member Functions
static char *	strndup_root (MEM_ROOT *root, const char *str, size_t len)

Public Attributes
const char *	str
size_t	length
Lazy *	deferred
	encapsulated expression to evaluate it later (on demand) More...

Detailed Description

Helper class to keep string data in MEM_ROOT before passing to Item_string.

Since Item_string constructors doesn't copy input string parameter data in the most cases, those input strings must have the same lifetime as Item_string objects, i.e. lifetime of MEM_ROOT. This class allocates input parameters for Item_string objects in MEM_ROOT.

Note

Call to is_empty() is necessary before the access to "str" and "length" fields, since is_empty() may trigger an evaluation of an associated expression that updates these fields.

Constructor & Destructor Documentation

mem_root_str()

qep_row::mem_root_str::mem_root_str ( )

inline

Member Function Documentation

cleanup()

void qep_row::mem_root_str::cleanup ( )

inline

is_empty()

bool qep_row::mem_root_str::is_empty

(

)

set() [1/4]

bool qep_row::mem_root_str::set ( const char *  str_arg )

inline

set() [2/4]

bool qep_row::mem_root_str::set	(	const char *	str_arg,
		size_t	length_arg
	)

Make a copy of the string in MEM_ROOT.

Parameters

str_arg	string to copy
length_arg	input string length

Returns

false if success, true if error

set() [3/4]

bool qep_row::mem_root_str::set ( const String &  s )

inline

set() [4/4]

void qep_row::mem_root_str::set ( Lazy *  x )

inline

Save expression for further evaluation.

Parameters

x	Expression

set_const() [1/2]

void qep_row::mem_root_str::set_const ( const char *  str_arg )

inline

Make a copy of string constant.

Variant of set() usable when the str_arg argument lives longer than the mem_root_str instance.

set_const() [2/2]

void qep_row::mem_root_str::set_const ( const char *  str_arg, size_t  length_arg  )

inline

strndup_root()

static char * qep_row::mem_root_str::strndup_root ( MEM_ROOT *  root, const char *  str, size_t  len  )

inlinestatic

Member Data Documentation

deferred

Lazy* qep_row::mem_root_str::deferred

encapsulated expression to evaluate it later (on demand)

length

size_t qep_row::mem_root_str::length

str

const char* qep_row::mem_root_str::str

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The documentation for this struct was generated from the following files:

• sql/opt_explain_format.h
• sql/opt_explain_format.cc