Adding upstream version 1:10.5.12.upstream/1%10.5.12upstream

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

1 files changed, 165 insertions, 0 deletions

diff --git a/sql/ha_sequence.h b/sql/ha_sequence.h
new file mode 100644
index 00000000..72e59a40
--- /dev/null
+++ b/sql/ha_sequence.h
@@ -0,0 +1,165 @@
+#ifndef HA_SEQUENCE_INCLUDED
+#define HA_SEQUENCE_INCLUDED
+/*
+   Copyright (c) 2017 Aliyun and/or its affiliates.
+   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
+*/
+
+#include "sql_sequence.h"
+#include "table.h"
+#include "handler.h"
+
+extern handlerton *sql_sequence_hton;
+
+/*
+  Sequence engine handler.
+
+  The sequence engine is a logic engine. It doesn't store any data.
+  All the sequence data stored into the base table which must support
+  non rollback writes (HA_CAN_TABLES_WITHOUT_ROLLBACK)
+
+  The sequence data (SEQUENCE class) is stored in TABLE_SHARE->sequence
+
+  TABLE RULES:
+      1. When table is created, one row is automaticlly inserted into
+         the table. The table will always have one and only one row.
+      2. Any inserts or updates to the table will be validated.
+      3. Inserts will overwrite the original row.
+      4. DELETE and TRUNCATE will not affect the table.
+         Instead a warning will be given.
+      5. Cache will be reset for any updates.
+
+  CACHE RULES:
+    SEQUENCE class is used to cache values that sequence defined.
+      1. If hit cache, we can query back the sequence nextval directly
+         instead of reading the underlying table.
+
+      2. When run out of values, the sequence engine will reserve new values
+         in update the base table.
+
+      3. The cache is invalidated if any update on based table.
+*/
+
+class ha_sequence :public handler
+{
+private:
+  handler *file;
+  SEQUENCE *sequence;                     /* From table_share->sequence */
+
+public:
+  /* Set when handler is write locked */
+  bool write_locked;
+
+  ha_sequence(handlerton *hton, TABLE_SHARE *share);
+  ~ha_sequence();
+
+  /* virtual function that are re-implemented for sequence */
+  int open(const char *name, int mode, uint test_if_locked);
+  int create(const char *name, TABLE *form,
+             HA_CREATE_INFO *create_info);
+  handler *clone(const char *name, MEM_ROOT *mem_root);
+  int write_row(const uchar *buf);
+  Table_flags table_flags() const;
+  /* One can't update or delete from sequence engine */
+  int update_row(const uchar *old_data, const uchar *new_data)
+  { return HA_ERR_WRONG_COMMAND; }
+  int delete_row(const uchar *buf)
+  { return HA_ERR_WRONG_COMMAND; }
+  /* One can't delete from sequence engine */
+  int truncate()
+  { return HA_ERR_WRONG_COMMAND; }
+  /* Can't use query cache */
+  uint8 table_cache_type()
+  { return HA_CACHE_TBL_NOCACHE; }
+  void print_error(int error, myf errflag);
+  int info(uint);
+  LEX_CSTRING *engine_name() { return hton_name(file->ht); }
+  int external_lock(THD *thd, int lock_type);
+  int extra(enum ha_extra_function operation);
+  /* For ALTER ONLINE TABLE */
+  bool check_if_incompatible_data(HA_CREATE_INFO *create_info,
+                                  uint table_changes);
+  void write_lock() { write_locked= 1;}
+  void unlock() { write_locked= 0; }
+  bool is_locked() { return write_locked; }
+
+  /* Functions that are directly mapped to the underlying handler */
+  int rnd_init(bool scan)
+  { return file->rnd_init(scan); }
+  /*
+    We need to have a lock here to protect engines like MyISAM from
+    simultaneous read and write. For sequence's this is not critical
+    as this function is used extremely seldom.
+  */
+  int rnd_next(uchar *buf)
+  {
+    int error;
+    table->s->sequence->read_lock(table);
+    error= file->rnd_next(buf);
+    table->s->sequence->read_unlock(table);
+    return error;
+  }
+  int rnd_end()
+  { return file->rnd_end(); }
+  int rnd_pos(uchar *buf, uchar *pos)
+  {
+    int error;
+    table->s->sequence->read_lock(table);
+    error= file->rnd_pos(buf, pos);
+    table->s->sequence->read_unlock(table);
+    return error;
+  }
+  void position(const uchar *record)
+  { return file->position(record); }
+  const char *table_type() const
+  { return file->table_type(); }
+  ulong index_flags(uint inx, uint part, bool all_parts) const
+  { return file->index_flags(inx, part, all_parts); }
+  THR_LOCK_DATA **store_lock(THD *thd, THR_LOCK_DATA **to,
+                             enum thr_lock_type lock_type)
+  { return file->store_lock(thd, to, lock_type); }
+  int close(void)
+  { return file->close(); }
+  const char **bas_ext() const
+  { return file->bas_ext(); }
+  int delete_table(const char*name)
+  { return file->delete_table(name); }
+  int rename_table(const char *from, const char *to)
+  { return file->rename_table(from, to); }
+  void unbind_psi()
+  { file->unbind_psi(); }
+  void rebind_psi()
+  { file->rebind_psi(); }
+
+  bool auto_repair(int error) const
+  { return file->auto_repair(error); }
+  int repair(THD* thd, HA_CHECK_OPT* check_opt)
+  { return file->repair(thd, check_opt); }
+  bool check_and_repair(THD *thd)
+  { return file->check_and_repair(thd); }
+  bool is_crashed() const
+  { return file->is_crashed(); }
+  void column_bitmaps_signal()
+  { return file->column_bitmaps_signal(); }
+
+  /* New methods */
+  void register_original_handler(handler *file_arg)
+  {
+    file= file_arg;
+    init();                                     /* Update cached_table_flags */
+  }
+};
+#endif