mariadb/sql/select_handler.h
Vicențiu Ciorbaru 08c852026d Apply clang-tidy to remove empty constructors / destructors
This patch is the result of running
run-clang-tidy -fix -header-filter=.* -checks='-*,modernize-use-equals-default' .

Code style changes have been done on top. The result of this change
leads to the following improvements:

1. Binary size reduction.
* For a -DBUILD_CONFIG=mysql_release build, the binary size is reduced by
  ~400kb.
* A raw -DCMAKE_BUILD_TYPE=Release reduces the binary size by ~1.4kb.

2. Compiler can better understand the intent of the code, thus it leads
   to more optimization possibilities. Additionally it enabled detecting
   unused variables that had an empty default constructor but not marked
   so explicitly.

   Particular change required following this patch in sql/opt_range.cc

   result_keys, an unused template class Bitmap now correctly issues
   unused variable warnings.

   Setting Bitmap template class constructor to default allows the compiler
   to identify that there are no side-effects when instantiating the class.
   Previously the compiler could not issue the warning as it assumed Bitmap
   class (being a template) would not be performing a NO-OP for its default
   constructor. This prevented the "unused variable warning".
2023-02-09 16:09:08 +02:00

72 lines
2 KiB
Objective-C

/*
Copyright (c) 2018, 2019 MariaDB
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 SELECT_HANDLER_INCLUDED
#define SELECT_HANDLER_INCLUDED
#include "mariadb.h"
#include "sql_priv.h"
/**
@class select_handler
This interface class is to be used for execution of select queries
by foreign engines
*/
class select_handler
{
public:
THD *thd;
handlerton *ht;
SELECT_LEX *select; // Select to be excuted
/*
Temporary table where all results should be stored in record[0]
The table has a field for every item from the select_lex::item_list.
The table is actually never filled. Only its record buffer is used.
*/
TABLE *table;
select_handler(THD *thd_arg, handlerton *ht_arg)
: thd(thd_arg), ht(ht_arg), table(0) {}
virtual ~select_handler() = default;
/*
Functions to scan the select result set.
All these returns 0 if ok, error code in case of error.
*/
/* Initialize the process of producing rows of result set */
virtual int init_scan() = 0;
/*
Put the next produced row of the result set in table->record[0]
and return 0. Return HA_ERR_END_OF_FILE if there are no more rows,
return other error number in case of fatal error.
*/
virtual int next_row() = 0;
/* Finish scanning */
virtual int end_scan() = 0;
/* Report errors */
virtual void print_error(int error, myf errflag);
};
#endif /* SELECT_HANDLER_INCLUDED */