SessionListener.h

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/*
* Copyright Onix Solutions Limited [OnixS]. All rights reserved.
*
* This software owned by Onix Solutions Limited [OnixS] and is protected by copyright law
* and international copyright treaties.
*
* Access to and use of the software is governed by the terms of the applicable OnixS Software
* Services Agreement (the Agreement) and Customer end user license agreements granting
* a non-assignable, non-transferable and non-exclusive license to use the software
* for it's own data processing purposes under the terms defined in the Agreement.
*
* Except as otherwise granted within the terms of the Agreement, copying or reproduction of any part
* of this source code or associated reference material to any other location for further reproduction
* or redistribution, and any amendments to this copyright notice, are expressly prohibited.
*
* Any reproduction or redistribution for sale or hiring of the Software not in accordance with
* the terms of the Agreement is a violation of copyright law.
*/

#pragma once

#include <OnixS/CME/ConflatedTCP/ABI.h>
#include <OnixS/CME/ConflatedTCP/Messaging.h>
#include <OnixS/CME/ConflatedTCP/SessionStateId.h>

#include <string>

namespace OnixS {
namespace CME {
namespace ConflatedTCP {

ONIXS_CONFLATEDTCP_API_DECL(class, Session);

/**
 * Session Warning Reason.
 */
struct SessionWarningReason
{
    enum Enum
    {
        /// General session-related warning.
        GeneralWarning,

        /// Incoming message sequence gap is detected.
        SequenceGapIsDetected,

        /// Received the <a href="https://www.cmegroup.com/confluence/display/EPICSANDBOX/Sequence">Sequence</a> message with
        /// the `Lapsed` value of the `KeepAliveIntervalLapsed` field.
        SequenceWithKeepAliveLapsed,

        /// Unexpected SBE Schema version is received from CME.
        UnexpectedSbeSchemaVersion,

        /// The value of the `PreviousUUID` field in the received
        /// <a href="https://www.cmegroup.com/confluence/display/EPICSANDBOX/Establishment+Acknowledgment">Establishment Acknowledgment</a>
        /// message does not match to the local value.
        UnexpectedPreviousUuid,

        /// Received an unsupported message type.
        UnsupportedMessageType
    };
};

/**
 * Session Error Reason.
 */
struct SessionErrorReason
{
    enum Enum
    {
        /// A general session-related error.
        GeneralError,

        /// First message received is not the <i>NegotiationResponse</i> or <i>EstablishmentAck</i> message.
        UnexpectedMessageType,

        /// The <i>Negotiation Reject</i> message is received in reply to the <i>Negotiation</i> message.
        NegotiationReject,

        /// The <i>Establishment Reject</i> message is received in reply to the <i>Establish</i> message.
        EstablishmentReject,

        /// The <i>Retransmit Reject</i> message is received in reply to the <i>Retransmit Request</i> message.
        RetransmitReject,

        /// The <i>Terminate</i> message is received in reply to the <i>Establish</i> message.
        TerminateInReplyOnEstablish,

        /// The incoming message has a sequence number less than expected and the <i>PossDupFlag</i> is not
        /// set, it indicates a serious error.
        /// The incoming message has a sequence number less than expected and the <i>PossDupFlag</i> is not set, it
        /// indicates a serious error. It is strongly recommended that the session be terminated and manual intervention
        /// be initiated.
        MsgSeqNumTooLow,

        /// Connection cannot be restored.
        CannotRestoreConnection,

        /// Connection cannot be established.
        CannotEstablishConnection,

        /// Exception during processing of an incoming message.
        ExceptionDuringProcessingOfIncomingMessage,

        /// Received an invalid incoming message.
        DecodingError,

        /// Exception was thrown from user's event handler.
        ExceptionInEventHandler,

        /// A response has not been received during the specified timeout.
        ResponseTimeoutException,

        /// When two times the `KeepAliveInterval` has expired and no keep alive
        /// message is received then the session is terminated ungracefully and will need to be re-established.
        KeepAliveIntervalLapsed,

        /// Telecommunication link error is detected.
        LinkErrorIsDetected,

        /// After sending the initial Negotiate or Establish message the telecommunication link error is detected.
        LinkErrorIsDetectedDuringSessionEstablishment,

        /// Received an unexpected `NextSeqNo` value.
        UnexpectedNextSeqNo,

        /// The program is finishing its execution.
        ProgramIsFinishing,

        /// The Exchange sent the initial Terminate message.
        ExchangeInitiatedTerminateMessage
    };
};

/// Session's Listener.
class ONIXS_CONFLATEDTCP_EXPORTED SessionListener
{
public:
    virtual void onNegotiationReject(const Messaging::NegotiationReject201 & /*msg*/, Session * /*sn*/) {}
    virtual void onNegotiationResponse(const Messaging::NegotiationResponse202& /*msg*/, Session* /*sn*/) {}
    virtual void onTerminate(const Messaging::Terminate203& /*msg*/, Session* /*sn*/) {}
    virtual void onRequestAck(const Messaging::RequestAck206& /*msg*/, Session* /*sn*/) {}
    virtual void onRequestReject(const Messaging::RequestReject207& /*msg*/, Session* /*sn*/) {}

    /// Called when the application-level message is sent to the counterparty.
    virtual void onOutboundApplicationMsg(const Messaging::SbeMessage& /*msg*/, Session* /*sn*/) {}

    /// Called when the session-level message is sent to the counterparty.
    virtual void onOutboundSessionMsg(const Messaging::SbeMessage& /*msg*/, Session * /*sn*/) {}

    /// Called as soon as bytes are received from the wire.
    virtual void onReceivedBytes(const char * /*bytes*/, size_t /*size*/, Session * /*sn*/) {}

    /// Called when the SBE message is about to be sent to the wire.
    virtual void onMessageSending(char * /*bytes*/, size_t /*size*/, Session * /*sn*/) {}

    /// Called when the session changes its state.
    virtual void onStateChange(SessionStateId::Enum /*newState*/, SessionStateId::Enum /*prevState*/, Session * /*sn*/) {}

    /// Called when an error condition is detected.
    virtual void onError(SessionErrorReason::Enum /*reason*/, const std::string & /*description*/, Session * /*sn*/) {}

    /// Called when a warning condition is detected.
    virtual void onWarning(SessionWarningReason::Enum /*reason*/, const std::string & /*description*/, Session * /*sn*/) {}

    protected:
    virtual ~SessionListener() = 0;
};

}
}
}