1 #ifndef CONNECTION_HANDLER_INCLUDED
2 #define CONNECTION_HANDLER_INCLUDED
3 
4 /* Copyright (c) 2007, 2021, Oracle and/or its affiliates.
5 
6    This program is free software; you can redistribute it and/or modify
7    it under the terms of the GNU General Public License, version 2.0,
8    as published by the Free Software Foundation.
9 
10    This program is also distributed with certain software (including
11    but not limited to OpenSSL) that is licensed under separate terms,
12    as designated in a particular file or component or in included license
13    documentation.  The authors of MySQL hereby grant you an additional
14    permission to link the program and your derivative works with the
15    separately licensed software that they have included with MySQL.
16 
17    This program is distributed in the hope that it will be useful,
18    but WITHOUT ANY WARRANTY; without even the implied warranty of
19    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
20    GNU General Public License, version 2.0, for more details.
21 
22    You should have received a copy of the GNU General Public License
23    along with this program; if not, write to the Free Software Foundation,
24    51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */
25 
26 #include "my_global.h"     // uint
27 
28 class THD;
29 class Channel_info;
30 class Connection_handler_manager;
31 
32 
33 /**
34   This abstract base class represents how connections are processed,
35   most importantly how they map to OS threads.
36 */
37 class Connection_handler
38 {
39 protected:
40   friend class Connection_handler_manager;
41 
Connection_handler()42   Connection_handler() {}
~Connection_handler()43   virtual ~Connection_handler() {}
44 
45   /**
46     Add a connection.
47 
48     @param channel_info     Pointer to the Channel_info object.
49 
50     @note If this function is successful (returns false), the ownership of
51     channel_info is transferred. Otherwise the caller is responsible for
52     its destruction.
53 
54     @return true if processing of the new connection failed, false otherwise.
55   */
56   virtual bool add_connection(Channel_info* channel_info) = 0;
57 
58   /**
59     @return Maximum number of threads that can be created
60             by this connection handler.
61   */
62   virtual uint get_max_threads() const = 0;
63 };
64 
65 #endif // CONNECTION_HANDLER_INCLUDED
66