req_msg_source_impl.cc

/* -*- c++ -*- */
/*
 * Copyright 2013,2014,2019 Free Software Foundation, Inc.
 *
 * This file is part of GNU Radio.
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "req_msg_source_impl.h"
#include "tag_headers.h"
#include <gnuradio/io_signature.h>
#include <boost/thread/thread.hpp>
#include <chrono>
#include <memory>
#include <thread>

namespace gr {
namespace zeromq {

req_msg_source::sptr req_msg_source::make(char* address, int timeout, bool bind)
{
    return gnuradio::make_block_sptr<req_msg_source_impl>(address, timeout, bind);
}

req_msg_source_impl::req_msg_source_impl(char* address, int timeout, bool bind)
    : gr::block("req_msg_source",
                gr::io_signature::make(0, 0, 0),
                gr::io_signature::make(0, 0, 0)),
      d_timeout(timeout),
      d_context(1),
      d_socket(d_context, ZMQ_REQ),
      d_port(pmt::mp("out"))
{
    int major, minor, patch;
    zmq::version(&major, &minor, &patch);

    if (major < 3) {
        d_timeout = timeout * 1000;
    }

    int time = 0;
    d_socket.setsockopt(ZMQ_LINGER, &time, sizeof(time));

    if (bind) {
        d_socket.bind(address);
    } else {
        d_socket.connect(address);
    }

    message_port_register_out(d_port);
}

req_msg_source_impl::~req_msg_source_impl() {}

bool req_msg_source_impl::start()
{
    d_finished = false;
    d_thread = std::make_unique<boost::thread>([this] { readloop(); });
    return true;
}

bool req_msg_source_impl::stop()
{
    d_finished = true;
    d_thread->join();
    return true;
}

void req_msg_source_impl::readloop()
{
    using namespace std::chrono_literals;
    while (!d_finished) {
        // std::cout << "readloop\n";

        zmq::pollitem_t itemsout[] = {
            { static_cast<void*>(d_socket), 0, ZMQ_POLLOUT, 0 }
        };
        zmq::poll(&itemsout[0], 1, d_timeout);

        //  If we got a reply, process
        if (itemsout[0].revents & ZMQ_POLLOUT) {
            // Request data, FIXME non portable?
            int nmsg = 1;
            zmq::message_t request(sizeof(int));
            memcpy((void*)request.data(), &nmsg, sizeof(int));
#if USE_NEW_CPPZMQ_SEND_RECV
            d_socket.send(request, zmq::send_flags::none);
#else
            d_socket.send(request);
#endif
        }

        zmq::pollitem_t items[] = { { static_cast<void*>(d_socket), 0, ZMQ_POLLIN, 0 } };
        zmq::poll(&items[0], 1, d_timeout);

        //  If we got a reply, process
        if (items[0].revents & ZMQ_POLLIN) {
            // Receive data
            zmq::message_t msg;
#if USE_NEW_CPPZMQ_SEND_RECV
            const bool ok = bool(d_socket.recv(msg));
#else
            const bool ok = d_socket.recv(&msg);
#endif
            if (!ok) {
                // Should not happen, we've checked POLLIN.
                GR_LOG_ERROR(d_logger, "Failed to receive message.");
                std::this_thread::sleep_for(100us);
                continue;
            }

            std::string buf(static_cast<char*>(msg.data()), msg.size());
            std::stringbuf sb(buf);
            try {
                pmt::pmt_t m = pmt::deserialize(sb);
                message_port_pub(d_port, m);
            } catch (pmt::exception& e) {
                GR_LOG_ERROR(d_logger, std::string("Invalid PMT message: ") + e.what());
            }

        } else {
            std::this_thread::sleep_for(100us);
        }
    }
}

} /* namespace zeromq */
} /* namespace gr */