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Filename : item_vers.h
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#ifndef ITEM_VERS_INCLUDED
#define ITEM_VERS_INCLUDED
/* 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 Street, Fifth Floor, Boston, MA  02110-1301, USA */


/* System Versioning items */

#ifdef USE_PRAGMA_INTERFACE
#pragma interface			/* gcc class implementation */
#endif

class Item_func_history: public Item_bool_func
{
public:
  /*
     @param    a  Item_field for row_end system field
  */
  Item_func_history(THD *thd, Item *a): Item_bool_func(thd, a)
  {
    DBUG_ASSERT(a->type() == Item::FIELD_ITEM);
  }

  bool val_bool() override;
  bool fix_length_and_dec() override
  {
    set_maybe_null();
    null_value= 0;
    decimals= 0;
    max_length= 1;
    return FALSE;
  }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN("is_history") };
    return name;
  }
  void print(String *str, enum_query_type query_type) override;
  Item *do_get_copy(THD *thd) const override
  { return get_item_copy<Item_func_history>(thd, this); }
};

class Item_func_trt_ts: public Item_datetimefunc
{
  TR_table::field_id_t trt_field;
public:
  Item_func_trt_ts(THD *thd, Item* a, TR_table::field_id_t _trt_field);
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING begin_name=  {STRING_WITH_LEN("trt_begin_ts") };
    static LEX_CSTRING commit_name= {STRING_WITH_LEN("trt_commit_ts") };
    return (trt_field == TR_table::FLD_BEGIN_TS) ? begin_name : commit_name;
  }
  bool get_date(THD *thd, MYSQL_TIME *res, date_mode_t fuzzydate) override;
  Item *do_get_copy(THD *thd) const override
  { return get_item_copy<Item_func_trt_ts>(thd, this); }
  bool fix_length_and_dec() override
  { fix_attributes_datetime(decimals); return FALSE; }
};

class Item_func_trt_id : public Item_longlong_func
{
  TR_table::field_id_t trt_field;
  bool backwards;

  longlong get_by_trx_id(ulonglong trx_id);
  longlong get_by_commit_ts(MYSQL_TIME &commit_ts, bool backwards);

public:
  Item_func_trt_id(THD *thd, Item* a, TR_table::field_id_t _trt_field, bool _backwards= false);
  Item_func_trt_id(THD *thd, Item* a, Item* b, TR_table::field_id_t _trt_field);

  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING trx_name= {STRING_WITH_LEN("trt_trx_id") };
    static LEX_CSTRING commit_name= {STRING_WITH_LEN("trt_commit_id") };
    static LEX_CSTRING iso_name= {STRING_WITH_LEN("trt_iso_level") };

    switch (trt_field) {
    case TR_table::FLD_TRX_ID:
      return trx_name;
    case TR_table::FLD_COMMIT_ID:
      return commit_name;
    case TR_table::FLD_ISO_LEVEL:
      return iso_name;
    default:
      DBUG_ASSERT(0);
    }
    return NULL_clex_str;
  }

  bool fix_length_and_dec() override
  {
    bool res= Item_int_func::fix_length_and_dec();
    max_length= 20;
    return res;
  }

  longlong val_int() override;
  Item *do_get_copy(THD *thd) const override
  { return get_item_copy<Item_func_trt_id>(thd, this); }
};

class Item_func_trt_trx_sees : public Item_bool_func
{
protected:
  bool accept_eq;

public:
  Item_func_trt_trx_sees(THD *thd, Item* a, Item* b);
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN("trt_trx_sees") };
    return name;
  }
  bool val_bool() override;
  Item *do_get_copy(THD *thd) const override
  { return get_item_copy<Item_func_trt_trx_sees>(thd, this); }
};

class Item_func_trt_trx_sees_eq :
  public Item_func_trt_trx_sees
{
public:
  Item_func_trt_trx_sees_eq(THD *thd, Item* a, Item* b) :
    Item_func_trt_trx_sees(thd, a, b)
  {
    accept_eq= true;
  }
  LEX_CSTRING func_name_cstring() const override
  {
    static LEX_CSTRING name= {STRING_WITH_LEN("trt_trx_sees_eq") };
    return name;
  }
};

#endif /* ITEM_VERS_INCLUDED */