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
|
/*
Copyright (c) 2009-2011 250bpm s.r.o.
Copyright (c) 2007-2011 iMatix Corporation
Copyright (c) 2011 VMware, Inc.
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 "fq.hpp"
#include "pipe.hpp"
#include "err.hpp"
#include "msg.hpp"
zmq::fq_t::fq_t () :
active (0),
current (0),
more (false)
{
}
zmq::fq_t::~fq_t ()
{
zmq_assert (pipes.empty ());
}
void zmq::fq_t::attach (pipe_t *pipe_)
{
pipes.push_back (pipe_);
pipes.swap (active, pipes.size () - 1);
active++;
}
void zmq::fq_t::terminated (pipe_t *pipe_)
{
// Remove the pipe from the list; adjust number of active pipes
// accordingly.
if (pipes.index (pipe_) < active) {
active--;
if (current == active)
current = 0;
}
pipes.erase (pipe_);
}
void zmq::fq_t::activated (pipe_t *pipe_)
{
// Move the pipe to the list of active pipes.
pipes.swap (pipes.index (pipe_), active);
active++;
}
int zmq::fq_t::recv (msg_t *msg_, int flags_)
{
return recvpipe (msg_, flags_, NULL);
}
int zmq::fq_t::recvpipe (msg_t *msg_, int flags_, pipe_t **pipe_)
{
// Deallocate old content of the message.
int rc = msg_->close ();
errno_assert (rc == 0);
// Round-robin over the pipes to get the next message.
for (pipes_t::size_type count = active; count != 0; count--) {
// Try to fetch new message. If we've already read part of the message
// subsequent part should be immediately available.
bool fetched = pipes [current]->read (msg_);
// Check the atomicity of the message. If we've already received the
// first part of the message we should get the remaining parts
// without blocking.
zmq_assert (!(more && !fetched));
// Note that when message is not fetched, current pipe is deactivated
// and replaced by another active pipe. Thus we don't have to increase
// the 'current' pointer.
if (fetched) {
if (pipe_)
*pipe_ = pipes [current];
more =
msg_->flags () & msg_t::more ? true : false;
if (!more) {
current++;
if (current >= active)
current = 0;
}
return 0;
}
else {
active--;
pipes.swap (current, active);
if (current == active)
current = 0;
}
}
// No message is available. Initialise the output parameter
// to be a 0-byte message.
rc = msg_->init ();
errno_assert (rc == 0);
errno = EAGAIN;
return -1;
}
bool zmq::fq_t::has_in ()
{
// There are subsequent parts of the partly-read message available.
if (more)
return true;
// Note that messing with current doesn't break the fairness of fair
// queueing algorithm. If there are no messages available current will
// get back to its original value. Otherwise it'll point to the first
// pipe holding messages, skipping only pipes with no messages available.
for (pipes_t::size_type count = active; count != 0; count--) {
if (pipes [current]->check_read ())
return true;
// Deactivate the pipe.
active--;
pipes.swap (current, active);
if (current == active)
current = 0;
}
return false;
}
|
