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/*
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 <string.h>
#include "../include/zmq.h"
#include "xsub.hpp"
#include "err.hpp"
zmq::xsub_t::xsub_t (class ctx_t *parent_, uint32_t tid_) :
socket_base_t (parent_, tid_),
fq (this),
has_message (false),
more (false)
{
options.type = ZMQ_XSUB;
options.requires_in = true;
options.requires_out = false;
zmq_msg_init (&message);
}
zmq::xsub_t::~xsub_t ()
{
zmq_msg_close (&message);
}
void zmq::xsub_t::xattach_pipes (class reader_t *inpipe_,
class writer_t *outpipe_, const blob_t &peer_identity_)
{
zmq_assert (inpipe_ && !outpipe_);
fq.attach (inpipe_);
}
void zmq::xsub_t::process_term (int linger_)
{
fq.terminate ();
socket_base_t::process_term (linger_);
}
int zmq::xsub_t::xsend (zmq_msg_t *msg_, int options_)
{
size_t size = zmq_msg_size (msg_);
unsigned char *data = (unsigned char*) zmq_msg_data (msg_);
// Malformed subscriptions are dropped silently.
if (size >= 1) {
// Process a subscription.
if (*data == 1)
subscriptions.add (data + 1, size - 1);
// Process an unsubscription. Invalid unsubscription is ignored.
if (*data == 0)
subscriptions.rm (data + 1, size - 1);
}
int rc = zmq_msg_close (msg_);
zmq_assert (rc == 0);
rc = zmq_msg_init (msg_);
zmq_assert (rc == 0);
return 0;
}
bool zmq::xsub_t::xhas_out ()
{
// Subscription can be added/removed anytime.
return true;
}
int zmq::xsub_t::xrecv (zmq_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) {
zmq_msg_move (msg_, &message);
has_message = false;
more = msg_->flags & ZMQ_MSG_MORE;
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 || match (msg_)) {
more = msg_->flags & ZMQ_MSG_MORE;
return 0;
}
// Message doesn't match. Pop any remaining parts of the message
// from the pipe.
while (msg_->flags & ZMQ_MSG_MORE) {
rc = fq.recv (msg_, ZMQ_NOBLOCK);
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_NOBLOCK);
// 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 (match (&message)) {
has_message = true;
return true;
}
// Message doesn't match. Pop any remaining parts of the message
// from the pipe.
while (message.flags & ZMQ_MSG_MORE) {
rc = fq.recv (&message, ZMQ_NOBLOCK);
zmq_assert (rc == 0);
}
}
}
bool zmq::xsub_t::match (zmq_msg_t *msg_)
{
return subscriptions.check ((unsigned char*) zmq_msg_data (msg_),
zmq_msg_size (msg_));
}
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