// Cyphesis Online RPG Server and AI Engine
// Copyright (C) 2000-2004 Alistair Riddoch
//
// 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 2 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

// $Id: af47cdf93fe400d269e7083cc5a73c8a921000a1 $

#ifndef SERVER_COMM_SOCKET_H
#define SERVER_COMM_SOCKET_H

class CommServer;

/// \brief Base class for all classes for handling socket communication.
/// \ingroup ServerSockets
class CommSocket {
  protected:
    explicit CommSocket(CommServer & svr);
  public:
    /// Reference to the object that manages all socket communication.
    CommServer & m_commServer;

    /// \brief Destructor.
    virtual ~CommSocket();

    /// \brief Get the socket file descriptor.
    ///
    /// Used to determine if this socket required attention using select().
    virtual int getFd() const = 0;

    /// \brief Determine whether this socket is open.
    /// @return true if the socket conneciton is open, false otherwise.
    virtual bool isOpen() const = 0;

    /// \brief Determine whether this socket has hung up.
    /// @return true if the socket conneciton has hung up, false otherwise.
    virtual bool eof() = 0;

    /// \brief Read data from the socket.
    ///
    /// Called when select has determined that this socket requires attention.
    /// This function should read data from the socket and do any initial
    /// processing required, but must not write to the socket. Writing to
    /// to the socket during this function could result in a timeout
    /// which could result in the server locking up. An processing of the
    /// incoming date which might result in a write to the socket must
    /// be performed in the dispatch() memeber function.
    /// @return true if some exceptional circumstance occured meaning this
    /// socket is no longer usable, false otherwise.
    virtual int read() = 0;

    /// \brief Post process data read from the socket.
    ///
    /// Called after read(), this function should perform post any processing
    /// or dispatch on data that has been read which might result in
    /// writing to the client. A typical example is an Atlas operation
    /// from the client which might have a reply. The Atlas decode is performed
    /// in read(), but the dispatch is delayed until dispatch(). It is
    /// important to use this function correctly, as allowing interaction with
    /// the socket during the read() call can cause the socket to change state
    /// while the data is still being read. This can a cause hangs or
    /// unpredictable behavior especially in the Atlas::Codec code.
    virtual void dispatch() = 0;

    /// \brief Disconnect cleanly
    ///
    /// Politely inform the far end that we are done. This is normally done
    /// by shutting down the TCP connection
    virtual void disconnect() = 0;

    /// \brief Flush the socket
    virtual int flush();
};

#endif // SERVER_COMM_SOCKET_H
