serial.cpp

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/*
 * Copyright 2013,2014 Vladimir Ermakov.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <cassert>
#include <console_bridge/console.h>

#include <mavconn/thread_utils.h>
#include <mavconn/serial.h>

namespace mavconn {
using boost::system::error_code;
using boost::asio::io_service;
using boost::asio::serial_port_base;
using boost::asio::buffer;
typedef std::lock_guard<std::recursive_mutex> lock_guard;


MAVConnSerial::MAVConnSerial(uint8_t system_id, uint8_t component_id,
                std::string device, unsigned baudrate) :
        MAVConnInterface(system_id, component_id),
        tx_in_progress(false),
        io_service(),
        serial_dev(io_service)
{
        logInform("serial%d: device: %s @ %d bps", channel, device.c_str(), baudrate);

        try {
                serial_dev.open(device);

                // Sent baudrate, and 8N1 mode
                serial_dev.set_option(serial_port_base::baud_rate(baudrate));
                serial_dev.set_option(serial_port_base::character_size(8));
                serial_dev.set_option(serial_port_base::parity(serial_port_base::parity::none));
                serial_dev.set_option(serial_port_base::stop_bits(serial_port_base::stop_bits::one));
                serial_dev.set_option(serial_port_base::flow_control(serial_port_base::flow_control::none));
        }
        catch (boost::system::system_error &err) {
                throw DeviceError("serial", err);
        }

        // give some work to io_service before start
        io_service.post(boost::bind(&MAVConnSerial::do_read, this));

        // run io_service for async io
        std::thread t(boost::bind(&io_service::run, &this->io_service));
        mavutils::set_thread_name(t, "MAVConnSerial%d", channel);
        io_thread.swap(t);
}

MAVConnSerial::~MAVConnSerial() {
        close();
}

void MAVConnSerial::close() {
        lock_guard lock(mutex);
        if (!is_open())
                return;

        serial_dev.close();
        io_service.stop();

        // clear tx queue
        std::for_each(tx_q.begin(), tx_q.end(),
                        [](MsgBuffer *p) { delete p; });
        tx_q.clear();

        if (io_thread.joinable())
                io_thread.join();

        /* emit */ port_closed();
}

void MAVConnSerial::send_bytes(const uint8_t *bytes, size_t length)
{
        if (!is_open()) {
                logError("serial%d:send: channel closed!", channel);
                return;
        }

        MsgBuffer *buf = new MsgBuffer(bytes, length);
        {
                lock_guard lock(mutex);
                tx_q.push_back(buf);
        }
        io_service.post(boost::bind(&MAVConnSerial::do_write, this, true));
}

void MAVConnSerial::send_message(const mavlink_message_t *message, uint8_t sysid, uint8_t compid)
{
        assert(message != nullptr);

        if (!is_open()) {
                logError("serial%d:send: channel closed!", channel);
                return;
        }

        logDebug("serial%d:send: Message-Id: %d [%d bytes]", channel, message->msgid, message->len);

        MsgBuffer *buf = new_msgbuffer(message, sysid, compid);
        {
                lock_guard lock(mutex);
                tx_q.push_back(buf);
        }
        io_service.post(boost::bind(&MAVConnSerial::do_write, this, true));
}

void MAVConnSerial::do_read(void)
{
        serial_dev.async_read_some(
                        buffer(rx_buf, sizeof(rx_buf)),
                        boost::bind(&MAVConnSerial::async_read_end,
                                this,
                                boost::asio::placeholders::error,
                                boost::asio::placeholders::bytes_transferred));
}

void MAVConnSerial::async_read_end(error_code error, size_t bytes_transferred)
{
        mavlink_message_t message;
        mavlink_status_t status;

        if (error) {
                logError("serial%d:receive: %s", channel, error.message().c_str());
                close();
                return;
        }

        for (ssize_t i = 0; i < bytes_transferred; i++) {
                if (mavlink_parse_char(channel, rx_buf[i], &message, &status)) {
                        logDebug("serial%d:recv: Message-Id: %d [%d bytes] Sys-Id: %d Comp-Id: %d",
                                        channel, message.msgid, message.len, message.sysid, message.compid);

                        /* emit */ message_received(&message, message.sysid, message.compid);
                }
        }

        do_read();
}

void MAVConnSerial::do_write(bool check_tx_state)
{
        if (check_tx_state && tx_in_progress)
                return;

        lock_guard lock(mutex);
        if (tx_q.empty())
                return;

        tx_in_progress = true;
        MsgBuffer *buf = tx_q.front();
        serial_dev.async_write_some(
                        buffer(buf->dpos(), buf->nbytes()),
                        boost::bind(&MAVConnSerial::async_write_end,
                                this,
                                boost::asio::placeholders::error,
                                boost::asio::placeholders::bytes_transferred));
}

void MAVConnSerial::async_write_end(error_code error, size_t bytes_transferred)
{
        if (error) {
                logError("serial%d:write: %s", channel, error.message().c_str());
                close();
                return;
        }

        lock_guard lock(mutex);
        if (tx_q.empty()) {
                tx_in_progress = false;
                return;
        }

        MsgBuffer *buf = tx_q.front();
        buf->pos += bytes_transferred;
        if (buf->nbytes() == 0) {
                tx_q.pop_front();
                delete buf;
        }

        if (!tx_q.empty())
                do_write(false);
        else
                tx_in_progress = false;
}

}; // namespace mavconn