mysql5/mysql-5.7.27/sql/opt_explain_json.h

51 lines
1.6 KiB
C++

/* Copyright (c) 2011, 2015, Oracle and/or its affiliates. All rights reserved.
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,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */
#ifndef OPT_EXPLAIN_FORMAT_JSON_INCLUDED
#define OPT_EXPLAIN_FORMAT_JSON_INCLUDED
#include "opt_explain_format.h"
namespace opt_explain_json_namespace
{
class context;
}
/**
Formatter class for EXPLAIN FORMAT=JSON output
*/
class Explain_format_JSON : public Explain_format
{
private:
opt_explain_json_namespace::context *current_context; ///< current tree node
Query_result *output;
public:
Explain_format_JSON() : current_context(NULL), output(NULL) {}
virtual bool is_hierarchical() const { return true; }
virtual bool send_headers(Query_result *result);
virtual bool begin_context(enum_parsing_context context,
SELECT_LEX_UNIT *subquery,
const Explain_format_flags *flags);
virtual bool end_context(enum_parsing_context context);
virtual bool flush_entry() { return false; }
virtual qep_row *entry();
};
#endif//OPT_EXPLAIN_FORMAT_JSON_INCLUDED