From 3f619478f796eddbba6e39502fe941b285dd97b1 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 4 May 2024 20:00:34 +0200 Subject: Adding upstream version 1:10.11.6. Signed-off-by: Daniel Baumann --- sql/sql_limit.h | 101 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 sql/sql_limit.h (limited to 'sql/sql_limit.h') diff --git a/sql/sql_limit.h b/sql/sql_limit.h new file mode 100644 index 00000000..335aff9d --- /dev/null +++ b/sql/sql_limit.h @@ -0,0 +1,101 @@ +/* Copyright (c) 2019, 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 02110-1335 USA */ + + +#ifndef INCLUDES_MARIADB_SQL_LIMIT_H +#define INCLUDES_MARIADB_SQL_LIMIT_H +/** + LIMIT/OFFSET parameters for execution. +*/ + +class Select_limit_counters +{ + ha_rows select_limit_cnt, offset_limit_cnt; + bool with_ties; + + public: + Select_limit_counters(): + select_limit_cnt(0), offset_limit_cnt(0), with_ties(false) + {}; + Select_limit_counters(const Select_limit_counters &orig): + select_limit_cnt(orig.select_limit_cnt), + offset_limit_cnt(orig.offset_limit_cnt), + with_ties(orig.with_ties) + {}; + + void set_limit(ha_rows limit, ha_rows offset, bool with_ties_arg) + { + if (limit == 0) + offset= 0; + offset_limit_cnt= offset; + select_limit_cnt= limit; + with_ties= with_ties_arg; + /* + Guard against an overflow condition, where limit + offset exceede + ha_rows value range. This case covers unreasonably large parameter + values that do not have any practical use so assuming in this case + that the query does not have a limit is fine. + */ + if (select_limit_cnt + offset_limit_cnt >= select_limit_cnt) + select_limit_cnt+= offset_limit_cnt; + else + select_limit_cnt= HA_POS_ERROR; + } + + void set_single_row() + { + offset_limit_cnt= 0; + select_limit_cnt= 1; + with_ties= false; + } + + /* Send the first row, still honoring offset_limit_cnt */ + void send_first_row() + { + /* Guard against overflow */ + if ((select_limit_cnt= offset_limit_cnt +1 ) == 0) + select_limit_cnt= offset_limit_cnt; + // with_ties= false; Remove // on merge to 10.6 + } + + bool is_unlimited() const + { return select_limit_cnt == HA_POS_ERROR; } + /* + Set the limit to allow returning an unlimited number of rows. Useful + for cases when we want to continue execution indefinitely after the limit + is reached (for example for SQL_CALC_ROWS extension). + */ + void set_unlimited() + { select_limit_cnt= HA_POS_ERROR; } + + /* Reset the limit entirely. */ + void clear() + { select_limit_cnt= HA_POS_ERROR; offset_limit_cnt= 0; with_ties= false;} + + bool check_offset(ha_rows sent) const + { + return sent < offset_limit_cnt; + } + void remove_offset() { offset_limit_cnt= 0; } + + ha_rows get_select_limit() const + { return select_limit_cnt; } + ha_rows get_offset_limit() const + { return offset_limit_cnt; } + bool is_with_ties() const + { return with_ties; } +}; + +#endif // INCLUDES_MARIADB_SQL_LIMIT_H -- cgit v1.2.3