1/*
2 Copyright (c) 2007-2016 Contributors as noted in the AUTHORS file
3
4 This file is part of libzmq, the ZeroMQ core engine in C++.
5
6 libzmq is free software; you can redistribute it and/or modify it under
7 the terms of the GNU Lesser General Public License (LGPL) as published
8 by the Free Software Foundation; either version 3 of the License, or
9 (at your option) any later version.
10
11 As a special exception, the Contributors give you permission to link
12 this library with independent modules to produce an executable,
13 regardless of the license terms of these independent modules, and to
14 copy and distribute the resulting executable under terms of your choice,
15 provided that you also meet, for each linked independent module, the
16 terms and conditions of the license of that module. An independent
17 module is a module which is not derived from or based on this library.
18 If you modify this library, you must extend this exception to your
19 version of the library.
20
21 libzmq is distributed in the hope that it will be useful, but WITHOUT
22 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
23 FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
24 License for more details.
25
26 You should have received a copy of the GNU Lesser General Public License
27 along with this program. If not, see <http://www.gnu.org/licenses/>.
28*/
29
30#ifndef __ZMQ_LB_HPP_INCLUDED__
31#define __ZMQ_LB_HPP_INCLUDED__
32
33#include "array.hpp"
34
35namespace zmq
36{
37class msg_t;
38class pipe_t;
39
40// This class manages a set of outbound pipes. On send it load balances
41// messages fairly among the pipes.
42
43class lb_t
44{
45 public:
46 lb_t ();
47 ~lb_t ();
48
49 void attach (pipe_t *pipe_);
50 void activated (pipe_t *pipe_);
51 void pipe_terminated (pipe_t *pipe_);
52
53 int send (msg_t *msg_);
54
55 // Sends a message and stores the pipe that was used in pipe_.
56 // It is possible for this function to return success but keep pipe_
57 // unset if the rest of a multipart message to a terminated pipe is
58 // being dropped. For the first frame, this will never happen.
59 int sendpipe (msg_t *msg_, pipe_t **pipe_);
60
61 bool has_out ();
62
63 private:
64 // List of outbound pipes.
65 typedef array_t<pipe_t, 2> pipes_t;
66 pipes_t _pipes;
67
68 // Number of active pipes. All the active pipes are located at the
69 // beginning of the pipes array.
70 pipes_t::size_type _active;
71
72 // Points to the last pipe that the most recent message was sent to.
73 pipes_t::size_type _current;
74
75 // True if last we are in the middle of a multipart message.
76 bool _more;
77
78 // True if we are dropping current message.
79 bool _dropping;
80
81 ZMQ_NON_COPYABLE_NOR_MOVABLE (lb_t)
82};
83}
84
85#endif
86