CClientTCPSocket.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */
#pragma once

#include <mrpt/utils/core_defs.h>
#include <cstdint>
#include <mrpt/utils/CStream.h>
#include <string>

namespace mrpt
{
namespace utils
{
class CMessage;
}
/** Serial and networking devices and utilities */
namespace comms
{
class CServerTCPSocket;

/** A TCP socket that can be connected to a TCP server, implementing MRPT's
 * CStream interface for passing objects as well as generic read/write methods.
  *  Unless otherwise noticed, operations are blocking.
  *
  *  Note that for convenience, DNS lookup is performed with a timeout
 * (default=3000ms), which can be changed by the static member
 * CClientTCPSocket::DNS_LOOKUP_TIMEOUT_MS
  * \ingroup mrpt_comms_grp
  */
class CClientTCPSocket : public mrpt::utils::CStream
{
        friend class CServerTCPSocket;

   public:
        /** See description of CClientTCPSocket */
        static unsigned int DNS_LOOKUP_TIMEOUT_MS;

   protected:
#ifdef MRPT_OS_WINDOWS
/** The handle for the connected TCP socket, or INVALID_SOCKET
  */
#if MRPT_WORD_SIZE == 64
        uint64_t m_hSock;
#else
        uint32_t m_hSock;
#endif
#else

        /** The handle for the connected TCP socket, or -1 */
        int m_hSock;
#endif
        /** The IP address of the remote part of the connection. */
        std::string m_remotePartIP;
        /** The TCP port of the remote part of the connection. */
        unsigned short m_remotePartPort;

        /** Introduces a virtual method responsible for reading from the stream
         * (This method BLOCKS)
          * This method is implemented as a call to "readAsync" with infinite
         * timeouts.
          * \sa readAsync */
        size_t Read(void* Buffer, size_t Count) override;

        /** Introduces a virtual method responsible for writing to the stream.
          *  Write attempts to write up to Count bytes to Buffer, and returns the
         * number of bytes actually written.
          *  This method is implemented as a call to "writeAsync" with infinite
         * timeouts.
          * \sa writeAsync */
        size_t Write(const void* Buffer, size_t Count) override;

        /** Returns a description of the last Sockets error */
        std::string getLastErrorStr();

   public:
        /** Default constructor \sa connect  */
        CClientTCPSocket();

        /** Destructor */
        ~CClientTCPSocket();

        /** Establishes a connection with a remote part.
          * \param remotePartAddress This string can be a host name, like "server"
         * or "www.mydomain.org", or an IP address "11.22.33.44".
          * \param remotePartTCPPort The port on the remote machine to connect to.
          * \param timeout_ms  The timeout to wait for the connection (0: NO
         * TIMEOUT)
          * \exception This method raises an exception if an error is found with a
         * textual description of the error.
          */
        void connect(
                const std::string& remotePartAddress, unsigned short remotePartTCPPort,
                unsigned int timeout_ms = 0);

        /** Returns true if this objects represents a successfully connected socket
         */
        bool isConnected();

        /** Closes the connection */
        void close();

        /** Writes a string to the socket.
          * \exception std::exception On communication errors
          */
        void sendString(const std::string& str);

        /** This virtual method has no effect in this implementation over a TCP
         * socket, and its use raises an exception */
        uint64_t Seek(
                uint64_t Offset, CStream::TSeekOrigin Origin = sFromBeginning) override
        {
                MRPT_START
                MRPT_UNUSED_PARAM(Offset);
                MRPT_UNUSED_PARAM(Origin);
                THROW_EXCEPTION("This method has no effect in this class!");
                MRPT_END
        }

        /** This virtual method has no effect in this implementation over a TCP
         * socket, and its use raises an exception */
        uint64_t getTotalBytesCount() override
        {
                MRPT_START
                THROW_EXCEPTION("This method has no effect in this class!");
                MRPT_END
        }

        /** This virtual method has no effect in this implementation over a TCP
         * socket, and its use raises an exception */
        uint64_t getPosition() override
        {
                MRPT_START
                THROW_EXCEPTION("This method has no effect in this class!");
                MRPT_END
        }

        /** A method for reading from the socket with an optional timeout.
          * \param Buffer The destination of data.
          * \param Cound The number of bytes to read.
          * \param timeoutStart_ms The maximum timeout (in milliseconds) to wait for
         * the starting of data from the other side.
          * \param timeoutBetween_ms The maximum timeout (in milliseconds) to wait
         * for a chunk of data after a previous one.
          *  Set timeout's to -1 to block until the desired number of bytes are
         * read, or an error happens.
          *  \return The number of actually read bytes.
          */
        size_t readAsync(
                void* Buffer, const size_t Count, const int timeoutStart_ms = -1,
                const int timeoutBetween_ms = -1);

        /** A method for writing to the socket with optional timeouts.
          *  The method supports writing block by block as the socket allows us to
         * write more data.
          * \param Buffer The data.
          * \param Cound The number of bytes to write.
          * \param timeout_ms The maximum timeout (in milliseconds) to wait for the
         * socket to be available for writing (for each block).
          *  Set timeout's to -1 to block until the desired number of bytes are
         * written, or an error happens.
          *  \return The number of actually written bytes.
          */
        size_t writeAsync(
                const void* Buffer, const size_t Count, const int timeout_ms = -1);

        /** Send a message through the TCP stream.
          * \param outMsg The message to be shown.
          * \param timeout_ms The maximum timeout (in milliseconds) to wait for the
         * socket in each write operation.
          * \return Returns false on any error, or true if everything goes fine.
          */
        bool sendMessage(
                const mrpt::utils::CMessage& outMsg, const int timeout_ms = -1);

        /** Waits for an incoming message through the TCP stream.
          * \param inMsg The received message is placed here.
          * \param timeoutStart_ms The maximum timeout (in milliseconds) to wait for
         * the starting of data from the other side.
          * \param timeoutBetween_ms The maximum timeout (in milliseconds) to wait
         * for a chunk of data after a previous one.
          * \return Returns false on any error (or timeout), or true if everything
         * goes fine.
          */
        bool receiveMessage(
                mrpt::utils::CMessage& inMsg, const unsigned int timeoutStart_ms = 100,
                const unsigned int timeoutBetween_ms = 1000);

        /** Return the number of bytes already in the receive queue (they can be
         * read without waiting) */
        size_t getReadPendingBytes();

        /** Set the TCP no delay option of the protocol (Nagle algorithm).
          * \param newValue New value (0 enable Nagle algorithm, 1 disable).
          * \return Return a number lower than 0 if any error occurred.
          */
        int setTCPNoDelay(const int& newValue);

        /** Return the value of the TCPNoDelay option. */
        int getTCPNoDelay();

        /** Set the size of the SO send buffer. This buffer is used to store data,
         * and is sended when is full.
          * \param newValue New size of the SO send buffer.
          * \return Return a number lower than 0 if any error occurred.
          */
        int setSOSendBufffer(const int& newValue);

        /** Return the current size of the SO send buffer. */
        int getSOSendBufffer();

};  // End of class def.

}  // End of namespace
}  // end of namespace