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RMI for C++

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6 Aug 2009CPOL8 min read 838.1K   4.6K   153  
User-friendly remote method invocation in C++.
//*****************************************************************************
// RCF - Remote Call Framework
// Copyright (c) 2005. All rights reserved.
// Developed by Jarl Lindrud.
// Contact: jlindrud@hotmail.com .
//*****************************************************************************

#include <RCF/Connection.hpp>

#include <RCF/ByteOrdering.hpp>
#include <RCF/MethodInvocation.hpp>
#include <RCF/Token.hpp>
#include <RCF/util/Platform/Platform.hpp>
#include <RCF/util/Platform/OS/SocketInit.hpp>

#include <sys/timeb.h>
#include <sys/types.h>

namespace RCF {

    //******************************************************
    // nonblocking socket routines

    // time in ms since ca 1970, modulo 65536 s (ca 18.2 hrs)
    int getCurrentTimeMs()
    {
        struct _timeb timebuffer;
        _ftime( &timebuffer );
        int timeS = static_cast<int>(timebuffer.time);
        int timeMs = timebuffer.millitm;
        return (timeS & 0xffff)*1000 + timeMs;
    }

    int timedConnect(int timeoutMs, int fd, sockaddr *addr, int size)
    {
        int startTimeMs = getCurrentTimeMs();
        int endTimeMs = startTimeMs + timeoutMs;
        int ret = Platform::OS::Socket::connect(fd, addr, size);
        if ((ret == -1 && 
            Platform::OS::Socket::GetLastError() == Platform::OS::Socket::ERR_EWOULDBLOCK)
            ||
            (ret == -1 &&
            Platform::OS::Socket::GetLastError() == Platform::OS::Socket::ERR_EINPROGRESS))
        {
            fd_set fdSet;
            FD_ZERO(&fdSet);
            FD_SET(fd, &fdSet);
            int timeoutMs = endTimeMs - getCurrentTimeMs();
            timeoutMs = (timeoutMs > 0) ? timeoutMs : 0;
            timeval timeout;
            timeout.tv_sec = timeoutMs/1000;
            timeout.tv_usec = 1000*(timeoutMs%1000);
            if (timeout.tv_usec < 0)
            {
                timeout.tv_usec = 0;
            }
            ret = Platform::OS::Socket::select(fd+1, NULL, &fdSet, NULL, &timeout);
            if (ret == 1)
            {
                return 0;
            }
            else if (ret == 0)
            {
                RCF_TRACE("timedConnect - timeout")(fd)(timeout.tv_sec)(timeout.tv_usec);
                return -1;
            }
            else
            {
                int err = Platform::OS::Socket::GetLastError();
                RCF_TRACE("timedConnect - error")(fd)(timeout.tv_sec)(timeout.tv_usec)(err)(Platform::OS::GetErrorString(err));
                return -1;
            }
        }
        else if (ret == 0)
        {
            return 0;
        }
        else
        {
            int err = Platform::OS::Socket::GetLastError();
            RCF_TRACE("timedConnect - error")(fd)(err)(Platform::OS::GetErrorString(err));
            return -1;
        }
        
    }

    int timedRecv(int timeoutMs, int fd, char *buffer, int length, int flags)
    {
        int startTimeMs = getCurrentTimeMs();
        int endTimeMs = startTimeMs + timeoutMs;
        int bytesRead = 0;
        int bytesRemaining = length;
        int ret = 0;
        int err = 0;
        
        while (true)
        {
            ret = Platform::OS::Socket::recv(fd, buffer, bytesRemaining, flags);
            err = Platform::OS::Socket::GetLastError();
            if (ret > 0)
            {
                buffer += ret;
                bytesRead += ret;
                bytesRemaining -= ret;
                RCF_ASSERT(bytesRead >= 0 && bytesRemaining >= 0)(bytesRead)(bytesRemaining)(ret);
                if (bytesRemaining > 0) 
                {
                    continue;
                }
                else if (bytesRemaining == 0)
                {
                    return bytesRead;
                }
            }
            else if (ret == 0)
            {
                return 0;
            }
            else if (
                ret == -1 && 
                err == Platform::OS::Socket::ERR_EWOULDBLOCK &&
                bytesRemaining > 0)
            {
                int timeoutMs = endTimeMs - getCurrentTimeMs();
                timeoutMs = (timeoutMs > 0) ? timeoutMs : 0;
                fd_set fdSet;
                FD_ZERO(&fdSet);
                FD_SET(fd, &fdSet);
                timeval timeout;
                timeout.tv_sec = timeoutMs/1000;
                timeout.tv_usec = 1000*(timeoutMs%1000);
                ret = Platform::OS::Socket::select(fd+1, &fdSet, NULL, NULL, &timeout);
                RCF_ASSERT(ret == -1 || ret == 0 || ret == 1)(ret);
                if (ret == 1)
                {
                    continue;
                }
                else if (ret == 0)
                {
                    RCF_TRACE("timedRecv - select() timeout")(fd)(timeout.tv_sec)(timeout.tv_usec);
                    return -2;
                }
                else if (ret == -1)
                {
                    err = Platform::OS::Socket::GetLastError();
                    RCF_TRACE("timedRecv - select() error")(fd)(timeout.tv_sec)(timeout.tv_usec)(ret)(err)(Platform::OS::GetErrorString(err));
                    return -1;
                }
            }
            else if (ret == -1)
            {
                err = Platform::OS::Socket::GetLastError();
                RCF_TRACE("timedRecv - select() error")(fd)(ret)(err)(Platform::OS::GetErrorString(err));
                return -1;
            }
        }
    }

    int timedSend(int timeoutMs, int fd, const char *buffer, int length, int flags)
    {
        // TODO
        int startTimeMs = getCurrentTimeMs();
        int endTimeMs = startTimeMs + timeoutMs;
        int bytesRead = 0;
        int bytesRemaining = length;
        int ret = 0;
        int err = 0;
        while (true)
        {
            ret = Platform::OS::Socket::send(fd, buffer, bytesRemaining, flags);
            err = Platform::OS::Socket::GetLastError();

            if (ret > 0)
            {
                buffer += ret;
                bytesRead += ret;
                bytesRemaining -= ret;
                RCF_ASSERT(bytesRead >= 0 && bytesRemaining >= 0)(bytesRead)(bytesRemaining)(ret);
                if (bytesRemaining > 0) 
                {
                    continue;
                }
                else if (bytesRemaining == 0)
                {
                    return bytesRead;
                }
            }
            else if (ret == 0)
            {
                RCF_ASSERT(0); // can this ever happen?
            }
            else if (
                ret == -1 && 
                err == Platform::OS::Socket::ERR_EWOULDBLOCK &&
                bytesRemaining > 0)
            {
                int timeoutMs = endTimeMs - getCurrentTimeMs();
                timeoutMs = (timeoutMs > 0) ? timeoutMs : 0;
                fd_set fdSet;
                FD_ZERO(&fdSet);
                FD_SET(fd, &fdSet);
                timeval timeout;
                timeout.tv_sec = timeoutMs/1000;
                timeout.tv_usec = 1000*(timeoutMs%1000);
                ret = Platform::OS::Socket::select(fd+1, NULL, &fdSet, NULL, &timeout);
                RCF_ASSERT(ret == -1 || ret == 0 || ret == 1)(ret);
                if (ret == 1)
                {
                    continue;
                }
                else if (ret == 0)
                {
                    RCF_TRACE("timedSend - select() timeout")(fd)(timeout.tv_sec)(timeout.tv_usec);
                    return -2;
                }
                else if (ret == -1)
                {
                    err = Platform::OS::Socket::GetLastError();
                    RCF_TRACE("timedSend - select() error")(fd)(timeout.tv_sec)(timeout.tv_usec)(ret)(err)(Platform::OS::GetErrorString(err));
                    return -1;
                }
            }
            else if (ret == -1)
            {
                err = Platform::OS::Socket::GetLastError();
                RCF_TRACE("timedSend - send() error")(fd)(ret)(err)(Platform::OS::GetErrorString(err));
                return -1;
            }
        }
    }

    
    //******************************************************
    // Socket

    Socket::Socket(const std::string &ip, int port) 
        : own(true), fd(-1), ip(ip), port(port)
    {}

    Socket::Socket(int fd) 
        : own(false), fd(fd), ip(), port()
    {}

    Socket::~Socket()
    {
        if (own && fd != -1)
        {
            close();
        }
    }

    int Socket::getFd()
    {
        if (fd == -1)
        {
            // establish a connection
            hostent *hostDesc = ::gethostbyname( ip.c_str() );
            std::string strIp = ::inet_ntoa( * (in_addr*) hostDesc->h_addr_list[0]);
            fd = static_cast<int>( ::socket(PF_INET, SOCK_STREAM, IPPROTO_TCP) );
            if (fd < 0)
            {
                RCF_THROW(RCF::ConnectionException, "unable to create socket")(fd);
            }
            Platform::OS::Socket::setblocking(fd, false);
            sockaddr_in serverAddr;
            memset(&serverAddr, 0, sizeof(serverAddr));
            serverAddr.sin_family = AF_INET;
            serverAddr.sin_addr.s_addr = ::inet_addr(strIp.c_str());
            //serverAddr.sin_port = ::htons(port); // the :: seems to screw up gcc (!?!)
            serverAddr.sin_port = htons(port); // the :: seems to screw up gcc (!?!)
            unsigned int timeoutMs = 1000;
            if (0 != timedConnect(timeoutMs, fd, (sockaddr*) &serverAddr, sizeof(serverAddr))) 
            {
                int err = Platform::OS::Socket::closesocket(fd);
                RCF_ASSERT( err == 0 );
                fd = -1;
                RCF_THROW(RCF::ConnectionException, "timed connection attempt failed")(strIp)(ip)(port);
            }
        }
        RCF_ASSERT(fd != -1);
        return fd;
    }

    void Socket::close()
    {
        int err = Platform::OS::Socket::closesocket(fd);
        if (err < 0)
        {
            int socket_err = Platform::OS::Socket::GetLastError();
            RCF_ASSERT(0)(fd)(err)(socket_err)(Platform::OS::GetErrorString(socket_err));
        }
        fd = -1;
        
    }
    
    bool Socket::isConnected()
    {
        if (fd == -1)
        {
            return false;
        }
        else
        {
            timeval tv = {0,0};
            fd_set readFds;
            FD_ZERO(&readFds);
            FD_SET(fd, &readFds);
            int ret = Platform::OS::Socket::select(fd+1, &readFds, NULL, NULL, &tv);
            if (ret == 1)
            {
                const int length = 1;
                char buffer[length];
                int ret = Platform::OS::Socket::recv(fd, buffer, length, MSG_PEEK);
                if (ret == 0)
                {
                    return false;
                }
                else if (ret == -1)
                {
                    ret = Platform::OS::Socket::GetLastError();
                    if (ret == Platform::OS::Socket::ERR_ECONNRESET || 
                        ret == Platform::OS::Socket::ERR_ECONNABORTED || 
                        ret == Platform::OS::Socket::ERR_ECONNREFUSED)
                    {
                        return false;
                    }
                }
            }
            return true;
        }
    }

    //******************************************************
    // Connection

    Connection::Connection(std::string ip, int port, unsigned int recvTimeoutMs, int protocol) :
        protocol(protocol),
        sock(ip, port),
        recvTimeoutMs(recvTimeoutMs)
    {
        RCF_TRACE("")(ip)(port);
    }

    Connection::Connection(int fd, unsigned int recvTimeoutMs, int protocol) :
        protocol(protocol),
        sock(fd),
        recvTimeoutMs(recvTimeoutMs)
    {
        RCF_TRACE("")(fd);
    }

    int Connection::recv(unsigned int timeoutMs, int fd, char *buffer, int length, int flags)
    {
        return timedRecv(timeoutMs, fd, buffer, length, flags);

        //Platform::OS::Socket::setblocking(fd, true);
        //int ret = ::recv(fd, buffer, length, flags);
        //Platform::OS::Socket::setblocking(fd, false);
        //return ret;
    }

    int Connection::receive()
    {
        RCF_TRACE("");

        int fd = sock.getFd();
        unsigned int length = 0;
        unsigned int timeout = recvTimeoutMs;
        int ret = recv(timeout, fd, (char *) &length, 4, 0);
        if (ret == 4)
        {
            Reorder<NetworkByteOrder, MachineByteOrder>()(&length, sizeof(length), 1);
            if (length > 1024*50) // 50K limit on message sizes, for now
            {
                RCF_THROW(RecvException, "too much data")(fd)(length);
            }
            std::vector<char> vec(length);
            ret = recv(timeout, fd, &vec[0], length, 0);
            if (ret == length)
            {
                std::string data(&vec[0], length);
                unbindInProtocol(); // TODO: necessary to do explicit unbind?
                ibuffer.str(data);
                ibuffer.clear();
                decodeProtocol();
                bindInProtocol();
                return ret;
            }
        }

        RCF_ASSERT( ret >= -2);
        if (ret == 0)
        {
            RCF_TRACE("Connection::receive - graceful close")(fd)(ret);
            return 0;
        }
        else if (ret == -1)
        {
            int socket_err = Platform::OS::Socket::GetLastError();
            RCF_TRACE("Connection::receive - error")(fd)(ret)(socket_err)(Platform::OS::GetErrorString(socket_err));
            return -1;
        }
        else if (ret == -2)
        {
            return -2; // time out
        }
        else //if (ret > 0)
        {
            RCF_TRACE("Connection::receive - not enough data")(fd)(ret);
            return -1;
        }
    }

    void Connection::close()
    {
        sock.close();
    }

    bool Connection::isConnected()
    {
        return sock.isConnected();
    }

    void Connection::prepareSend()
    {
        unbindOutProtocol(); // TODO: necesary to do explicit unbind?
        obuffer.str("");
        ibuffer.clear();
        encodeProtocol();
        bindOutProtocol();
    }

    int Connection::send()
    {
        RCF_TRACE("");

        int fd = sock.getFd();
        std::string packet = obuffer.str();
        int length = static_cast<int>(packet.length());
        Reorder<MachineByteOrder, NetworkByteOrder>()(&length, sizeof(length), 1);
        std::string data((char *) &length, 4);
        data.append(packet);

        unsigned int sendTimeoutMs = getRecvTimeoutMs() / 4;
        if (sendTimeoutMs < 0)
            sendTimeoutMs = 250;
        if (sendTimeoutMs > 5000)
            sendTimeoutMs = 5000;
        int err = timedSend(sendTimeoutMs, fd, data.c_str(), static_cast<int>(data.length()), 0);
        if (err != data.length())
        {
            int socket_err = Platform::OS::Socket::GetLastError();
            RCF_THROW(RCF::SendException, "timed send failure")(sendTimeoutMs)(fd)(err)(socket_err)(Platform::OS::GetErrorString(socket_err));
        }


        RCF_TRACE("")(data)(data.length())(fd);

        return static_cast<int>(data.length());
    }

    void Connection::encodeProtocol()
    {
        int protocol = getProtocol();
        if (protocol < 0 || protocol > 15)
        {
            RCF_THROW(RCF::SerializationException, "bad protocol number")(protocol);
        }
        char ch = static_cast<char>(protocol);
        obuffer << ch;
    }

    void Connection::decodeProtocol()
    {
        char ch = 0;
        ibuffer >> ch;
        int protocol = static_cast<int>(ch);
        if (protocol < 0 || protocol > 15)
        {
            RCF_THROW(RCF::SerializationException, "bad protocol number")(protocol);
        }
        setProtocol(protocol);
    }

    void Connection::bindInProtocol()
    {
        switch (protocol)
        {
        case 1: iprotocol1.bind(ibuffer); break;
        case 2: iprotocol2.bind(ibuffer); break;
        case 3: iprotocol3.bind(ibuffer); break;
        case 4: iprotocol4.bind(ibuffer); break;
        case 5: iprotocol5.bind(ibuffer); break;
        case 6: iprotocol6.bind(ibuffer); break;
        case 7: iprotocol7.bind(ibuffer); break;
        case 8: iprotocol8.bind(ibuffer); break;
        case 9: iprotocol9.bind(ibuffer); break;
        case 10: iprotocol10.bind(ibuffer); break;
        default: RCF_ASSERT(0);
        }
        getPointerContext().clear();
    }

    void Connection::unbindInProtocol()
    {
        switch (protocol)
        {
        case 1: iprotocol1.unbind(); break;
        case 2: iprotocol2.unbind(); break;
        case 3: iprotocol3.unbind(); break;
        case 4: iprotocol4.unbind(); break;
        case 5: iprotocol5.unbind(); break;
        case 6: iprotocol6.unbind(); break;
        case 7: iprotocol7.unbind(); break;
        case 8: iprotocol8.unbind(); break;
        case 9: iprotocol9.unbind(); break;
        case 10: iprotocol10.unbind(); break;
        default: RCF_ASSERT(0);
        }
    }

    void Connection::bindOutProtocol()
    {
        switch (protocol)
        {
        case 1: oprotocol1.bind(obuffer); break;
        case 2: oprotocol2.bind(obuffer); break;
        case 3: oprotocol3.bind(obuffer); break;
        case 4: oprotocol4.bind(obuffer); break;
        case 5: oprotocol5.bind(obuffer); break;
        case 6: oprotocol6.bind(obuffer); break;
        case 7: oprotocol7.bind(obuffer); break;
        case 8: oprotocol8.bind(obuffer); break;
        case 9: oprotocol9.bind(obuffer); break;
        case 10: oprotocol10.bind(obuffer); break;
        default: RCF_ASSERT(0);
        }
    }

    void Connection::unbindOutProtocol()
    {
        switch (protocol)
        {
        case 1: oprotocol1.unbind(); break;
        case 2: oprotocol2.unbind(); break;
        case 3: oprotocol3.unbind(); break;
        case 4: oprotocol4.unbind(); break;
        case 5: oprotocol5.unbind(); break;
        case 6: oprotocol6.unbind(); break;
        case 7: oprotocol7.unbind(); break;
        case 8: oprotocol8.unbind(); break;
        case 9: oprotocol9.unbind(); break;
        case 10: oprotocol10.unbind(); break;
        default: RCF_ASSERT(0);
        }
    }

}

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This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
Australia Australia
Software developer, from Sweden and now living in Canberra, Australia, working on distributed C++ applications. When he is not programming, Jarl enjoys skiing and playing table tennis. He derives immense satisfaction from referring to himself in third person.

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