CerealPort.cpp

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* Author: Gonçalo Cabrita on 01/10/2010
*********************************************************************/
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <termios.h>
#include <math.h>
#include <poll.h>
#include <signal.h>
#include <fcntl.h>
#include <iostream>
#include <fstream>
#include <stdexcept>

#include "cereal_port/CerealPort.h"

#define CEREAL_EXCEPT(except, msg, ...) \
{ \
    char buf[1000]; \
    snprintf(buf, 1000, msg " (in cereal::CerealPort::%s)" , ##__VA_ARGS__, __FUNCTION__); \
    throw except(buf); \
}

cereal::CerealPort::CerealPort() : fd_(-1)
{
        stream_thread_ = NULL;
}

cereal::CerealPort::~CerealPort()
{
        if(portOpen()) close();
}

void cereal::CerealPort::open(const char * port_name, int baud_rate)
{
        if(portOpen()) close();
  
        // Make IO non blocking. This way there are no race conditions that
        // cause blocking when a badly behaving process does a read at the same
        // time as us. Will need to switch to blocking for writes or errors
        // occur just after a replug event.
        fd_ = ::open(port_name, O_RDWR | O_NONBLOCK | O_NOCTTY);

        if(fd_ == -1)
        {
                const char *extra_msg = "";
                switch(errno)
                {
                        case EACCES:
                        extra_msg = "You probably don't have premission to open the port for reading and writing.";
                        break;

                        case ENOENT:
                        extra_msg = "The requested port does not exist. Is the hokuyo connected? Was the port name misspelled?";
                        break;
                }
                CEREAL_EXCEPT(cereal::Exception, "Failed to open port: %s. %s (errno = %d). %s", port_name, strerror(errno), errno, extra_msg);
        }
        
        try
        {       
                struct flock fl;
                fl.l_type = F_WRLCK;
                fl.l_whence = SEEK_SET;
                fl.l_start = 0;
                fl.l_len = 0;
                fl.l_pid = getpid();

                if(fcntl(fd_, F_SETLK, &fl) != 0)
                        CEREAL_EXCEPT(cereal::Exception, "Device %s is already locked. Try 'lsof | grep %s' to find other processes that currently have the port open.", port_name, port_name);

                // Settings for USB?
                struct termios newtio;
                tcgetattr(fd_, &newtio);
                memset (&newtio.c_cc, 0, sizeof (newtio.c_cc));
                newtio.c_cflag = CS8 | CLOCAL | CREAD;
                newtio.c_iflag = IGNPAR;
                newtio.c_oflag = 0;
                newtio.c_lflag = 0;
                cfsetspeed(&newtio, baud_rate);
                baud_ = baud_rate;

                // Activate new settings
                tcflush(fd_, TCIFLUSH);
                if(tcsetattr(fd_, TCSANOW, &newtio) < 0)
                        CEREAL_EXCEPT(cereal::Exception, "Unable to set serial port attributes. The port you specified (%s) may not be a serial port.", port_name); 
                usleep (200000);
        }
        catch(cereal::Exception& e)
        {
                // These exceptions mean something failed on open and we should close
                if(fd_ != -1) ::close(fd_);
                fd_ = -1;
                throw e;
        }
}

void cereal::CerealPort::close()
{
        int retval = 0;
        
        retval = ::close(fd_);

        fd_ = -1;

        if(retval != 0)
                CEREAL_EXCEPT(cereal::Exception, "Failed to close port properly -- error = %d: %s\n", errno, strerror(errno));
}

int cereal::CerealPort::write(const char * data, int length)
{
        int len = length==-1 ? strlen(data) : length;

        // IO is currently non-blocking. This is what we want for the more cerealon read case.
        int origflags = fcntl(fd_, F_GETFL, 0);
        fcntl(fd_, F_SETFL, origflags & ~O_NONBLOCK); // TODO: @todo can we make this all work in non-blocking?
        int retval = ::write(fd_, data, len);
        fcntl(fd_, F_SETFL, origflags | O_NONBLOCK);

        if(retval == len) return retval;
        else CEREAL_EXCEPT(cereal::Exception, "write failed");
}

int cereal::CerealPort::read(char * buffer, int max_length, int timeout)
{
        int ret;

        struct pollfd ufd[1];
        int retval;
        ufd[0].fd = fd_;
        ufd[0].events = POLLIN;

        if(timeout == 0) timeout = -1; // For compatibility with former behavior, 0 means no timeout. For poll, negative means no timeout.

        if((retval = poll(ufd, 1, timeout)) < 0) CEREAL_EXCEPT(cereal::Exception, "poll failed -- error = %d: %s", errno, strerror(errno));

        if(retval == 0) CEREAL_EXCEPT(cereal::TimeoutException, "timeout reached");
                
        if(ufd[0].revents & POLLERR) CEREAL_EXCEPT(cereal::Exception, "error on socket, possibly unplugged");
                
    ret = ::read(fd_, buffer, max_length);
                
        if(ret == -1 && errno != EAGAIN && errno != EWOULDBLOCK) CEREAL_EXCEPT(cereal::Exception, "read failed");
        
        return ret;
}

int cereal::CerealPort::readBytes(char * buffer, int length, int timeout)
{
        int ret;
        int current = 0;

        struct pollfd ufd[1];
        int retval;
        ufd[0].fd = fd_;
        ufd[0].events = POLLIN;

        if(timeout == 0) timeout = -1; // For compatibility with former behavior, 0 means no timeout. For poll, negative means no timeout.

        while(current < length)
        {
                if((retval = poll(ufd, 1, timeout)) < 0) CEREAL_EXCEPT(cereal::Exception, "poll failed -- error = %d: %s", errno, strerror(errno));

                if(retval == 0) CEREAL_EXCEPT(cereal::TimeoutException, "timeout reached");
                
                if(ufd[0].revents & POLLERR) CEREAL_EXCEPT(cereal::Exception, "error on socket, possibly unplugged");
                
        ret = ::read(fd_, &buffer[current], length-current);
                
                if(ret == -1 && errno != EAGAIN && errno != EWOULDBLOCK) CEREAL_EXCEPT(cereal::Exception, "read failed");

                current += ret;
        }
        return current;
}

int cereal::CerealPort::readLine(char * buffer, int length, int timeout)
{
        int ret;
        int current = 0;

        struct pollfd ufd[1];
        int retval;
        ufd[0].fd = fd_;
        ufd[0].events = POLLIN;

        if(timeout == 0) timeout = -1; // For compatibility with former behavior, 0 means no timeout. For poll, negative means no timeout.

        while(current < length-1)
        {
                if(current > 0)
                        if(buffer[current-1] == '\n')
                                return current;

                if((retval = poll(ufd, 1, timeout)) < 0) CEREAL_EXCEPT(cereal::Exception, "poll failed -- error = %d: %s", errno, strerror(errno));

                if(retval == 0) CEREAL_EXCEPT(cereal::TimeoutException, "timeout reached");
                
                if(ufd[0].revents & POLLERR) CEREAL_EXCEPT(cereal::Exception, "error on socket, possibly unplugged");
                
        ret = ::read(fd_, &buffer[current], length-current);
                
                if(ret == -1 && errno != EAGAIN && errno != EWOULDBLOCK) CEREAL_EXCEPT(cereal::Exception, "read failed");

                current += ret;
        }
        CEREAL_EXCEPT(cereal::Exception, "buffer filled without end of line being found");
}

bool cereal::CerealPort::readLine(std::string * buffer, int timeout)
{
        int ret;

        struct pollfd ufd[1];
        int retval;
        ufd[0].fd = fd_;
        ufd[0].events = POLLIN;

        if(timeout == 0) timeout = -1; // For compatibility with former behavior, 0 means no timeout. For poll, negative means no timeout.

        buffer->clear();
        while(buffer->size() < buffer->max_size()/2)
        {
                // Look for the end char
                ret = buffer->find_first_of('\n');
                if(ret > 0)
                {
                        // If it is there clear everything after it and return
                        buffer->erase(ret+1, buffer->size()-ret-1);
                        return true;
                }

                if((retval = poll(ufd, 1, timeout)) < 0) CEREAL_EXCEPT(cereal::Exception, "poll failed -- error = %d: %s", errno, strerror(errno));

                if(retval == 0) CEREAL_EXCEPT(cereal::TimeoutException, "timeout reached");
                
                if(ufd[0].revents & POLLERR) CEREAL_EXCEPT(cereal::Exception, "error on socket, possibly unplugged");
                
        char temp_buffer[128];
        ret = ::read(fd_, temp_buffer, 128);
                
                if(ret == -1 && errno != EAGAIN && errno != EWOULDBLOCK) CEREAL_EXCEPT(cereal::Exception, "read failed");

                // Append the new data to the buffer
        try{ buffer->append(temp_buffer, ret); }
        catch(std::length_error& le)
        {
            CEREAL_EXCEPT(cereal::Exception, "buffer filled without reaching end of data stream");
        }
        }
        CEREAL_EXCEPT(cereal::Exception, "buffer filled without end of line being found");
}

bool cereal::CerealPort::readBetween(std::string * buffer, char start, char end, int timeout)
{
        int ret;

        struct pollfd ufd[1];
        static std::string erased;
        int retval;
        ufd[0].fd = fd_;
        ufd[0].events = POLLIN;

        if(timeout == 0) timeout = -1; // For compatibility with former behavior, 0 means no timeout. For poll, negative means no timeout.

        // Clear the buffer before we start
        buffer->clear();
        while(buffer->size() < buffer->max_size()/2)
        {
                if((retval = poll(ufd, 1, timeout)) < 0) CEREAL_EXCEPT(cereal::Exception, "poll failed -- error = %d: %s", errno, strerror(errno));
                
                if(retval == 0) CEREAL_EXCEPT(cereal::TimeoutException, "timeout reached");
                
                if(ufd[0].revents & POLLERR) CEREAL_EXCEPT(cereal::Exception, "error on socket, possibly unplugged");

                // Append erased characters in last iteration
                if(!erased.empty())
                {
                        try
                        { 
                                buffer->append(erased);
                                erased.clear();
                        }
                catch(std::length_error& le)
                {
                    CEREAL_EXCEPT(cereal::Exception, "failed to append erased to buffer");
                }
            }
                
                char temp_buffer[3];
                ret = ::read(fd_, temp_buffer, 3);
        
                if(ret == -1 && errno != EAGAIN && errno != EWOULDBLOCK) CEREAL_EXCEPT(cereal::Exception, "read failed");
        
                // Append the new data to the buffer
                try{ buffer->append(temp_buffer, ret); }
        catch(std::length_error& le)
        {
            CEREAL_EXCEPT(cereal::Exception, "buffer filled without reaching end of data stream");
        }
        
        // Look for the start char
        ret = buffer->find_first_of(start);
        // If it is not on the buffer, clear it
        if(ret == -1) buffer->clear();
        // If it is there, but not on the first position clear everything behind it
        else if(ret > 0) buffer->erase(0, ret);
                
                // Look for the end char
                ret = buffer->find_first_of(end);
                if(ret > 0)
                {
                        // If it is there clear everything after it and return
                        erased = buffer->substr(ret+1, buffer->size()-ret-1);
                        //std::cout << "sobra |" << erased << "|\n";
                        buffer->erase(ret+1, buffer->size()-ret-1);
                        return true;
                }
        }
        CEREAL_EXCEPT(cereal::Exception, "buffer filled without reaching end of data stream");
}

int cereal::CerealPort::flush()
{
          int retval = tcflush(fd_, TCIOFLUSH);
          if(retval != 0) CEREAL_EXCEPT(cereal::Exception, "tcflush failed");
          
          return retval;
}

bool cereal::CerealPort::startReadStream(boost::function<void(char*, int)> f)
{
        if(stream_thread_ != NULL) return false;

        stream_stopped_ = false;
        stream_paused_ = false;
        
        readCallback = f;
        
        stream_thread_ = new boost::thread(boost::bind(&cereal::CerealPort::readThread, this));
        return true;
}

void cereal::CerealPort::readThread()
{
        char data[MAX_LENGTH];
        int ret;

        struct pollfd ufd[1];
        ufd[0].fd = fd_;
        ufd[0].events = POLLIN;
        
        while(!stream_stopped_)
        {
                if(!stream_paused_)
                {
                        if(poll(ufd, 1, 10) > 0)
                        {
                                if(!(ufd[0].revents & POLLERR))
                                {
                                        ret = ::read(fd_, data, MAX_LENGTH);
                                        if(ret>0)
                                        {
                                                readCallback(data, ret);
                                        }
                                }
                        }
                }
        }
}

bool cereal::CerealPort::startReadLineStream(boost::function<void(std::string*)> f)
{
        if(stream_thread_ != NULL) return false;

        stream_stopped_ = false;
        stream_paused_ = false;
        
        readLineCallback = f;
        
        stream_thread_ = new boost::thread(boost::bind(&cereal::CerealPort::readLineThread, this));
        return true;
}

void cereal::CerealPort::readLineThread()
{
        std::string data;
        bool error = false;

        while(!stream_stopped_)
        {
                if(!stream_paused_)
                {
                        error = false;
                        try{ readLine(&data, 100); }
                        catch(cereal::Exception& e)
                        { 
                                error = true;
                        }
                        
                        if(!error && data.size()>0) readLineCallback(&data);
                }
        }
}

bool cereal::CerealPort::startReadBetweenStream(boost::function<void(std::string*)> f, char start, char end)
{
        if(stream_thread_ != NULL) return false;

        stream_stopped_ = false;
        stream_paused_ = false;
        
        readBetweenCallback = f;
        
        stream_thread_ = new boost::thread(boost::bind(&cereal::CerealPort::readBetweenThread, this, start, end));
        return true;
}

void cereal::CerealPort::readBetweenThread(char start, char end)
{
        std::string data;
        bool error = false;

        while(!stream_stopped_)
        {
                if(!stream_paused_)
                {
                        error = false;
                        try{ readBetween(&data, start, end, 100); }
                        catch(cereal::Exception& e)
                        { 
                                error = true;
                        }
                        
                        if(!error && data.size()>0) readBetweenCallback(&data);
                }
        }
}

void cereal::CerealPort::stopStream()
{
        stream_stopped_ = true;
        stream_thread_->join();
        
        delete stream_thread_;
        stream_thread_ = NULL;
}

void cereal::CerealPort::pauseStream()
{
        stream_paused_ = true;
}

void cereal::CerealPort::resumeStream()
{
        stream_paused_ = false;
}

// EOF