1 /*
2    Copyright (c) 2014, 2021, Oracle and/or its affiliates.
3 
4    This program is free software; you can redistribute it and/or modify
5    it under the terms of the GNU General Public License, version 2.0,
6    as published by the Free Software Foundation.
7 
8    This program is also distributed with certain software (including
9    but not limited to OpenSSL) that is licensed under separate terms,
10    as designated in a particular file or component or in included license
11    documentation.  The authors of MySQL hereby grant you an additional
12    permission to link the program and your derivative works with the
13    separately licensed software that they have included with MySQL.
14 
15    This program is distributed in the hope that it will be useful,
16    but WITHOUT ANY WARRANTY; without even the implied warranty of
17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18    GNU General Public License, version 2.0, for more details.
19 
20    You should have received a copy of the GNU General Public License
21    along with this program; if not, write to the Free Software
22    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
23 */
24 
25 #ifndef SHOW_VARIABLE_QUERY_EXTRACTOR_INCLUDED
26 #define SHOW_VARIABLE_QUERY_EXTRACTOR_INCLUDED
27 
28 #include "i_callable.h"
29 #include "base/mysql_query_runner.h"
30 #include "mysql.h"
31 #include<string>
32 #include<vector>
33 
34 namespace Mysql{
35 namespace Tools{
36 namespace Base{
37 
38 /**
39   Extracts the value of server variable.
40  */
41 class Show_variable_query_extractor
42 {
43 public:
44   /**
45     Extract the value of server variable.
46 
47     @param[in] query_runner MySQL query runner to use.
48     @param[in] variable Name of variable to get value of.
49     @param[out] value reference to String to store variable value to.
50     @param[out] value reference to bool to store if variable was found.
51     @return nonzero if error was encountered.
52    */
53   static int64 get_variable_value(
54     Mysql_query_runner* query_runner, std::string variable,
55     std::string& value, bool& exists);
56 
57 private:
58   Show_variable_query_extractor();
59   /**
60     Result row callback to be used in query runner.
61    */
62   int64 extract_variable(const Mysql_query_runner::Row& result_row);
63 
64   /**
65   Temporary placeholder for extracted value.
66   */
67   std::string m_extracted_variable;
68 
69   /**
70   Temporary placeholder for value received flag.
71   */
72   bool m_exists;
73 };
74 
75 }
76 }
77 }
78 
79 #endif
80