1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
/*
Copyright (c) 2007-2011 iMatix Corporation
Copyright (c) 2007-2011 Other contributors as noted in the AUTHORS file
This file is part of 0MQ.
0MQ is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
0MQ 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "lb.hpp"
#include "pipe.hpp"
#include "err.hpp"
#include "msg.hpp"
zmq::lb_t::lb_t () :
active (0),
current (0),
more (false),
dropping (false)
{
}
zmq::lb_t::~lb_t ()
{
zmq_assert (pipes.empty ());
}
void zmq::lb_t::attach (pipe_t *pipe_)
{
pipes.push_back (pipe_);
pipes.swap (active, pipes.size () - 1);
active++;
}
void zmq::lb_t::terminated (pipe_t *pipe_)
{
pipes_t::size_type index = pipes.index (pipe_);
// If we are in the middle of multipart message and current pipe
// have disconnected, we have to drop the remainder of the message.
if (index == current && more)
dropping = true;
// Remove the pipe from the list; adjust number of active pipes
// accordingly.
if (index < active) {
active--;
if (current == active)
current = 0;
}
pipes.erase (pipe_);
}
void zmq::lb_t::activated (pipe_t *pipe_)
{
// Move the pipe to the list of active pipes.
pipes.swap (pipes.index (pipe_), active);
active++;
}
int zmq::lb_t::send (msg_t *msg_, int flags_)
{
// Drop the message if required. If we are at the end of the message
// switch back to non-dropping mode.
if (dropping) {
more = msg_->flags () & (msg_t::more | msg_t::label);
if (!more)
dropping = false;
int rc = msg_->close ();
errno_assert (rc == 0);
rc = msg_->init ();
zmq_assert (rc == 0);
return 0;
}
while (active > 0) {
if (pipes [current]->write (msg_)) {
more = msg_->flags () & (msg_t::more | msg_t::label);
break;
}
zmq_assert (!more);
active--;
if (current < active)
pipes.swap (current, active);
else
current = 0;
}
// If there are no pipes we cannot send the message.
if (active == 0) {
errno = EAGAIN;
return -1;
}
// If it's final part of the message we can fluch it downstream and
// continue round-robinning (load balance).
if (!more) {
pipes [current]->flush ();
current = (current + 1) % active;
}
// Detach the message from the data buffer.
int rc = msg_->init ();
errno_assert (rc == 0);
return 0;
}
bool zmq::lb_t::has_out ()
{
// If one part of the message was already written we can definitely
// write the rest of the message.
if (more)
return true;
while (active > 0) {
// Check whether zero-sized message can be written to the pipe.
msg_t msg;
int rc = msg.init ();
errno_assert (rc == 0);
if (pipes [current]->check_write (&msg)) {
rc = msg.close ();
errno_assert (rc == 0);
return true;
}
rc = msg.close ();
errno_assert (rc == 0);
// Deactivate the pipe.
active--;
pipes.swap (current, active);
if (current == active)
current = 0;
}
return false;
}
|
