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/* Copyright (c) 2017, MariaDB corporation
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 St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef SQL_SEQUENCE_INCLUDED
#define SQL_SEQUENCE_INCLUDED
#define seq_field_used_min_value 1
#define seq_field_used_max_value 2
#define seq_field_used_start 4
#define seq_field_used_increment 8
#define seq_field_used_cache 16
#define seq_field_used_cycle 32
#define seq_field_used_restart 64
#define seq_field_used_restart_value 128
#define seq_field_used_as 256
#define seq_field_specified_min_value 512
#define seq_field_specified_max_value 1024
/* Field position in sequence table for some fields we refer to directly */
#define NEXT_FIELD_NO 0
#define MIN_VALUE_FIELD_NO 1
#define ROUND_FIELD_NO 7
#include "mysql_com.h"
#include "sql_type_int.h"
class Create_field;
class Type_handler;
struct Sequence_field_definition
{
const char *field_name;
uint length;
const Type_handler *type_handler;
LEX_CSTRING comment;
ulong flags;
};
struct Sequence_row_definition
{
Sequence_field_definition fields[9];
};
/**
sequence_definition is used when defining a sequence as part of create
*/
class sequence_definition :public Sql_alloc
{
public:
sequence_definition():
min_value_from_parser(1, false),
max_value_from_parser(LONGLONG_MAX-1, false), start_from_parser(1, false),
increment(1), cache(1000), round(0), restart_from_parser(0, false),
cycle(0), used_fields(0),
/*
We use value type and is_unsigned instead of a handler because
Type_handler is incomplete, which we cannot initialise here with
&type_handler_slonglong.
*/
value_type(MYSQL_TYPE_LONGLONG), is_unsigned(false)
{}
longlong reserved_until;
longlong min_value;
longlong max_value;
longlong start;
Longlong_hybrid min_value_from_parser;
Longlong_hybrid max_value_from_parser;
Longlong_hybrid start_from_parser;
longlong increment;
longlong cache;
ulonglong round;
longlong restart; // alter sequence restart value
Longlong_hybrid restart_from_parser;
bool cycle;
uint used_fields; // Which fields where used in CREATE
enum_field_types value_type; // value type of the sequence
bool is_unsigned;
Type_handler const *value_type_handler();
/* max value for the value type, e.g. 32767 for smallint. */
longlong value_type_max();
/* min value for the value type, e.g. -32768 for smallint. */
longlong value_type_min();
bool check_and_adjust(THD *thd, bool set_reserved_until);
void store_fields(TABLE *table);
void read_fields(TABLE *table);
int write_initial_sequence(TABLE *table);
int write(TABLE *table, bool all_fields);
/* This must be called after sequence data has been updated */
void adjust_values(longlong next_value);
longlong truncate_value(const Longlong_hybrid& original);
inline void print_dbug()
{
DBUG_PRINT("sequence", ("reserved: %lld start: %lld increment: %lld min_value: %lld max_value: %lld cache: %lld round: %lld",
reserved_until, start, increment, min_value,
max_value, cache, round));
}
static bool is_allowed_value_type(enum_field_types type);
bool prepare_sequence_fields(List<Create_field> *fields, bool alter);
protected:
/*
The following values are the values from sequence_definition
merged with global auto_increment_offset and auto_increment_increment
*/
longlong real_increment;
longlong next_free_value;
};
/**
SEQUENCE is in charge of managing the sequence values.
It's also responsible to generate new values and updating the sequence
table (engine=SQL_SEQUENCE) trough it's specialized handler interface.
If increment is 0 then the sequence will be be using
auto_increment_increment and auto_increment_offset variables, just like
AUTO_INCREMENT is using.
*/
class SEQUENCE :public sequence_definition
{
public:
enum seq_init { SEQ_UNINTIALIZED, SEQ_IN_PREPARE, SEQ_IN_ALTER,
SEQ_READY_TO_USE };
SEQUENCE();
~SEQUENCE();
int read_initial_values(TABLE *table);
int read_stored_values(TABLE *table);
void write_lock(TABLE *table);
void write_unlock(TABLE *table);
void read_lock(TABLE *table);
void read_unlock(TABLE *table);
void copy(sequence_definition *seq)
{
sequence_definition::operator= (*seq);
adjust_values(reserved_until);
all_values_used= 0;
}
longlong next_value(TABLE *table, bool second_round, int *error);
int set_value(TABLE *table, longlong next_value, ulonglong round_arg,
bool is_used);
bool all_values_used;
seq_init initialized;
private:
/**
Check that a value is within a relevant bound
If increasing sequence, check that the value is lower than an
upper bound, otherwise check that the value is higher than a lower
bound.
@param in value The value to check
@param in upper The upper bound
@param in lower The lower bound
@param in increasing Which bound to check
@retval true The value is within the bound.
false The value is out of the bound.
*/
bool within_bound(const longlong value, const longlong upper,
const longlong lower, bool increasing)
{
return
(is_unsigned && increasing && (ulonglong) value < (ulonglong) upper) ||
(is_unsigned && !increasing && (ulonglong) value > (ulonglong) lower) ||
(!is_unsigned && increasing && value < upper) ||
(!is_unsigned && !increasing && value > lower);
}
/**
Increment a value, subject to truncation
Truncating to the nearer value between max_value + 1 and min_value
- 1
@param in value The original value
@param in increment The increment to add to the value
@return The value after increment and possible truncation
*/
longlong increment_value(longlong value, const longlong increment)
{
if (is_unsigned)
{
if (increment > 0)
{
if (/* in case value + increment overflows */
(ulonglong) value >
(ulonglong) max_value - (ulonglong) increment ||
/* in case max_value - increment underflows */
(ulonglong) value + (ulonglong) increment >
(ulonglong) max_value ||
/* in case both overflow and underflow happens (very
rarely, if not impossible) */
(ulonglong) value > (ulonglong) max_value)
/* Cast to ulonglong then back, in case max_value ==
LONGLONG_MAX as a ulonglong */
value= (longlong) ((ulonglong) max_value + 1);
else
value = (longlong) ((ulonglong) value + (ulonglong) increment);
}
else
{
if ((ulonglong) value - (ulonglong) (-increment) <
(ulonglong) min_value ||
(ulonglong) value <
(ulonglong) min_value + (ulonglong) (-increment) ||
(ulonglong) value < (ulonglong) min_value)
/* Cast to ulonglong then back, in case min_value ==
LONGLONG_MAX + 1 as a ulonglong */
value= (longlong) ((ulonglong) min_value - 1);
else
value = (longlong) ((ulonglong) value - (ulonglong) (-increment));
}
} else
if (increment > 0)
{
if (value >
(longlong) ((ulonglong) max_value - (ulonglong) increment) ||
(longlong) ((ulonglong) value + (ulonglong) increment) >
max_value ||
value > max_value)
value= max_value + 1;
else
value+= increment;
}
else
{
if ((longlong) ((ulonglong) value + (ulonglong) increment) <
min_value ||
value <
(longlong) ((ulonglong) min_value - (ulonglong) increment) ||
value < min_value)
value= min_value - 1;
else
value+= increment;
}
return value;
}
mysql_rwlock_t mutex;
};
/**
Class to cache last value of NEXT VALUE from the sequence
*/
class SEQUENCE_LAST_VALUE
{
public:
SEQUENCE_LAST_VALUE(uchar *key_arg, uint length_arg)
:key(key_arg), length(length_arg)
{}
~SEQUENCE_LAST_VALUE()
{ my_free((void*) key); }
/* Returns 1 if table hasn't been dropped or re-created */
bool check_version(TABLE *table);
void set_version(TABLE *table);
const uchar *key;
uint length;
bool null_value;
longlong value;
uchar table_version[MY_UUID_SIZE];
};
extern bool check_sequence_fields(LEX *lex, List<Create_field> *fields,
const LEX_CSTRING db,
const LEX_CSTRING table_name);
extern bool sequence_insert(THD *thd, LEX *lex, TABLE_LIST *table_list);
#endif /* SQL_SEQUENCE_INCLUDED */