/* 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 /* 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 /** sequence_definition is used when defining a sequence as part of create */ class sequence_definition :public Sql_alloc { public: sequence_definition(): min_value(1), max_value(LONGLONG_MAX-1), start(1), increment(1), cache(1000), round(0), restart(0), cycle(0), used_fields(0) {} longlong reserved_until; longlong min_value; longlong max_value; longlong start; longlong increment; longlong cache; ulonglong round; longlong restart; // alter sequence restart value bool cycle; uint used_fields; // Which fields where used in CREATE bool check_and_adjust(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); 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)); } 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); longlong increment_value(longlong value) { if (real_increment > 0) { if (value > max_value - real_increment || value + real_increment > max_value) value= max_value + 1; else value+= real_increment; } else { if (value + real_increment < min_value || value < min_value - real_increment) value= min_value - 1; else value+= real_increment; } return value; } bool all_values_used; seq_init initialized; private: 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]; }; class Create_field; extern bool prepare_sequence_fields(THD *thd, List<Create_field> *fields); 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 */