const failable start()

in components/chat/chat-sendreceiver.cpp [56:111]

• 41 lines of code
• 5 McCabe index (conditional complexity)

const failable<value> start(const list<value>& params) {
    // Extract the relay reference and the XMPP JID and password
    const bool hasRelay = !isNull(cddr(params));
    const lvvlambda rel = hasRelay? (lvvlambda)car(params) : lvvlambda();
    const list<value> props = hasRelay? cdr(params) : params;
    const value jid = ((lvvlambda)car(props))(nilListValue);
    const value pass = ((lvvlambda)cadr(props))(nilListValue);

    // Create an XMPP client session
    XMPPClient xc(jid, pass, false);
    const failable<bool> r = connect(xc);
    if (!hasContent(r))
        return mkfailure<value>(r);

    // Listen and relay messages in a worker thread
    worker w(3);
    const lambda<const failable<bool>(const value&, const value&, XMPPClient&)> rl = [rel](const value& jid, const value& val, unused XMPPClient& xc) -> const failable<bool> {
        // A relay function that posts the XMPP messages it receives to a relay component reference.
        if (isNull(rel))
            return true;
        debug(jid, "chat::relay::jid");
        debug(val, "chat::relay::value");
        const value res = rel(mklist<value>("post", mklist<value>(jid), val));
        return true;
    };

    // Subscribe and listen to the XMPP session.
    const lambda<const failable<bool>()> subscribe = [rl, xc]() -> const failable<bool> {
        const gc_pool pool;
        debug("chat::subscribe::listen");
        const failable<bool> r = listen(rl, const_cast<XMPPClient&>(xc));
        debug("chat::subscribe::stopped");
        return r;
    };
    submit<failable<bool> >(w, subscribe);

    // Return the chat sender/receiver component lambda function
    const lvvlambda senderReceiver = [xc, w](const list<value>& params) -> const value {
        const tuscany::value func(car(params));
        if (func == "post")
            return post(cdr(params), const_cast<XMPPClient&>(xc));

        // Stop the chat sender/receiver component
        if (func != "stop")
            return mkfailure<value>();
        debug("chat::sendreceiver::stop");

        // Disconnect and shutdown the worker thread
        disconnect(const_cast<XMPPClient&>(xc));
        cancel(const_cast<worker&>(w));
        debug("chat::sendreceiver::stopped");

        return failable<value>(value(lvvlambda()));
    };
    return value(senderReceiver);
}