summaryrefslogtreecommitdiff
path: root/src/xsub.cpp
blob: debcac807ee3c593b535b5f8d6b4beebd18fcaad (plain)
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
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
/*
    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 <string.h>

#include "xsub.hpp"
#include "err.hpp"

zmq::xsub_t::xsub_t (class ctx_t *parent_, uint32_t tid_) :
    socket_base_t (parent_, tid_),
    has_message (false),
    more (false)
{
    options.type = ZMQ_XSUB;
    int rc = message.init ();
    errno_assert (rc == 0);
}

zmq::xsub_t::~xsub_t ()
{
    int rc = message.close ();
    errno_assert (rc == 0);
}

void zmq::xsub_t::xattach_pipe (pipe_t *pipe_)
{
    zmq_assert (pipe_);
    fq.attach (pipe_);
    dist.attach (pipe_);

    //  Send all the cached subscriptions to the new upstream peer.
    subscriptions.apply (send_subscription, pipe_);
    pipe_->flush ();
}

void zmq::xsub_t::xread_activated (pipe_t *pipe_)
{
    fq.activated (pipe_);
}

void zmq::xsub_t::xwrite_activated (pipe_t *pipe_)
{
    dist.activated (pipe_);
}

void zmq::xsub_t::xterminated (pipe_t *pipe_)
{
    fq.terminated (pipe_);
    dist.terminated (pipe_);
}

void zmq::xsub_t::xhiccuped (pipe_t *pipe_)
{
    //  Send all the cached subscriptions to the hiccuped pipe.
    subscriptions.apply (send_subscription, pipe_);
    pipe_->flush ();
}

int zmq::xsub_t::xsend (msg_t *msg_, int flags_)
{
    size_t size = msg_->size ();
    unsigned char *data = (unsigned char*) msg_->data ();

    // Malformed subscriptions.
    if (size < 1 || (*data != 0 && *data != 1)) {
        errno = EINVAL;
        return -1;
    }

    // Process the subscription.
    if (*data == 1) {
        if (subscriptions.add (data + 1, size - 1))
            return dist.send_to_all (msg_, flags_);
        else
            return 0;
    }
    else if (*data == 0) {
        if (subscriptions.rm (data + 1, size - 1))
            return dist.send_to_all (msg_, flags_);
        else
            return 0;
    }

    zmq_assert (false);
    return -1;
}

bool zmq::xsub_t::xhas_out ()
{
    //  Subscription can be added/removed anytime.
    return true;
}

int zmq::xsub_t::xrecv (msg_t *msg_, int flags_)
{
    //  If there's already a message prepared by a previous call to zmq_poll,
    //  return it straight ahead.
    if (has_message) {
        int rc = msg_->move (message);
        errno_assert (rc == 0);
        has_message = false;
        more = msg_->flags () & msg_t::more ? true : false;
        return 0;
    }

    //  TODO: This can result in infinite loop in the case of continuous
    //  stream of non-matching messages which breaks the non-blocking recv
    //  semantics.
    while (true) {

        //  Get a message using fair queueing algorithm.
        int rc = fq.recv (msg_, flags_);

        //  If there's no message available, return immediately.
        //  The same when error occurs.
        if (rc != 0)
            return -1;

        //  Check whether the message matches at least one subscription.
        //  Non-initial parts of the message are passed 
        if (more || !options.filter || match (msg_)) {
            more = msg_->flags () & msg_t::more ? true : false;
            return 0;
        }

        //  Message doesn't match. Pop any remaining parts of the message
        //  from the pipe.
        while (msg_->flags () & msg_t::more) {
            rc = fq.recv (msg_, ZMQ_DONTWAIT);
            zmq_assert (rc == 0);
        }
    }
}

bool zmq::xsub_t::xhas_in ()
{
    //  There are subsequent parts of the partly-read message available.
    if (more)
        return true;

    //  If there's already a message prepared by a previous call to zmq_poll,
    //  return straight ahead.
    if (has_message)
        return true;

    //  TODO: This can result in infinite loop in the case of continuous
    //  stream of non-matching messages.
    while (true) {

        //  Get a message using fair queueing algorithm.
        int rc = fq.recv (&message, ZMQ_DONTWAIT);

        //  If there's no message available, return immediately.
        //  The same when error occurs.
        if (rc != 0) {
            zmq_assert (errno == EAGAIN);
            return false;
        }

        //  Check whether the message matches at least one subscription.
        if (!options.filter || match (&message)) {
            has_message = true;
            return true;
        }

        //  Message doesn't match. Pop any remaining parts of the message
        //  from the pipe.
        while (message.flags () & msg_t::more) {
            rc = fq.recv (&message, ZMQ_DONTWAIT);
            zmq_assert (rc == 0);
        }
    }
}

bool zmq::xsub_t::match (msg_t *msg_)
{
    return subscriptions.check ((unsigned char*) msg_->data (), msg_->size ());
}

void zmq::xsub_t::send_subscription (unsigned char *data_, size_t size_,
    void *arg_)
{
    pipe_t *pipe = (pipe_t*) arg_;

    //  Create the subsctription message.
    msg_t msg;
    int rc = msg.init_size (size_ + 1);
    zmq_assert (rc == 0);
    unsigned char *data = (unsigned char*) msg.data ();
    data [0] = 1;
    memcpy (data + 1, data_, size_);

    //  Send it to the pipe.
    bool sent = pipe->write (&msg);
    zmq_assert (sent);
}

zmq::xsub_session_t::xsub_session_t (io_thread_t *io_thread_, bool connect_,
      socket_base_t *socket_, const options_t &options_,
      const char *protocol_, const char *address_) :
    session_base_t (io_thread_, connect_, socket_, options_, protocol_,
        address_)
{
}

zmq::xsub_session_t::~xsub_session_t ()
{
}