Adding upstream version 1:10.11.6.upstream/1%10.11.6

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 101 insertions, 0 deletions

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