struct SocketDesc : public std::enable_shared_from_this<SocketDesc>
{
        curl_socket_t                   mCurlSocket;
        boost::asio::ip::tcp::socket *  mBoostSocket;
        int*                            mFDP;
};

void Ntwk_CurlMulti::EventCB(const boost::system::error_code & error, std::size_t bytes, std::weak_ptr<SocketDesc> inWeakSocket, int action)
{
    auto sharedSocket = inWeakSocket.lock();
    if (!sharedSocket)
    {
        printf("%s event_cb: socket already closed", __FUNCTION__);
        return;
    }

    /* make sure the event matches what are wanted */
    if(*sharedSocket->mFDP == action || *sharedSocket->mFDP == CURL_POLL_INOUT) {
        CURLMcode rc;
        if(error)
            action = CURL_CSELECT_ERR;
        auto curlSocket = sharedSocket->mCurlSocket;
        sharedSocket.reset();
        rc = curl_multi_socket_action(mMulti, curlSocket, action, &mStillRunning);
        
        if (!CheckCurlError("event_cb: curl_multi_socket_action", rc))
            return;
        
        this->CheckMultiInfo();
        
        if(mStillRunning <= 0) {
            printf("%s last transfer done, kill timeout", __FUNCTION__);
            mTimer->cancel();
        }
        
        sharedSocket = inWeakSocket.lock();
        if (!sharedSocket)
        {
            printf("%s event_cb: socket closed after curl_multi_socket_action", __FUNCTION__);
            return;
        }
        
        /* keep on watching.
         * the socket may have been closed and/or fdp may have been changed
         * in curl_multi_socket_action(), so check them both */
        if(!error &&
           (*sharedSocket->mFDP == action || *sharedSocket->mFDP == CURL_POLL_INOUT) && mStillRunning) {
            boost::asio::ip::tcp::socket *tcp_socket = sharedSocket->mBoostSocket;
            if(action == CURL_POLL_IN)
                tcp_socket->async_read_some(boost::asio::null_buffers(), boost::bind(&Ntwk_CurlMulti::EventCB, this, _1, _2, inWeakSocket, CURL_POLL_IN));
            else if(action == CURL_POLL_OUT)
                tcp_socket->async_write_some(boost::asio::null_buffers(), boost::bind(&Ntwk_CurlMulti::EventCB, this, _1, _2, inWeakSocket, CURL_POLL_OUT));
        }
    }
}