int do_roundtrip()

in net/http/client.cpp [200:278]
71 lines of code
20 McCabe index (conditional complexity)

    int do_roundtrip(Operation* op, Timeout tmo) {
        op->status_code = -1;
        if (tmo.timeout() == 0)
            LOG_ERROR_RETURN(ETIMEDOUT, ROUNDTRIP_FAILED, "connection timedout");
        auto &req = op->req;
        ISocketStream* s;
        if (m_proxy && !m_proxy_url.empty())
            s = get_dialer().dial(m_proxy_url, tmo.timeout());
        else if (!op->uds_path.empty())
            s = get_dialer().dial(op->uds_path, tmo.timeout());
        else
            s = get_dialer().dial(req, tmo.timeout());
        if (!s) {
            if (errno == ECONNREFUSED || errno == ENOENT) {
                LOG_ERROR_RETURN(0, ROUNDTRIP_FAST_RETRY, "connection refused")
            }
            LOG_ERROR_RETURN(0, ROUNDTRIP_NEED_RETRY, "connection failed");
        }

        SocketStream_ptr sock(s);
        LOG_DEBUG("Sending request ` `", req.verb(), req.target());
        if (req.send_header(sock.get()) < 0) {
            sock->close();
            req.reset_status();
            LOG_ERROR_RETURN(0, ROUNDTRIP_NEED_RETRY, "send header failed, retry");
        }
        sock->timeout(tmo.timeout());
        if (op->body_buffer_size > 0) {
            // send body_buffer
            if (req.write(op->body_buffer, op->body_buffer_size) < 0) {
                sock->close();
                req.reset_status();
                LOG_ERROR_RETURN(0, ROUNDTRIP_NEED_RETRY, "send body buffer failed, retry");
            }
        } else if (op->body_stream) {
            // send body_stream
            if (req.write_stream(op->body_stream) < 0) {
                sock->close();
                req.reset_status();
                LOG_ERROR_RETURN(0, ROUNDTRIP_NEED_RETRY, "send body stream failed, retry");
            }
        } else {
            // call body_writer
            if (op->body_writer(&req) < 0) {
                sock->close();
                req.reset_status();
                LOG_ERROR_RETURN(0, ROUNDTRIP_NEED_RETRY, "failed to call body writer, retry");
            }
        }

        if (req.send() < 0) {
            sock->close();
            req.reset_status();
            LOG_ERROR_RETURN(0, ROUNDTRIP_NEED_RETRY, "failed to ensure send");
        }

        LOG_DEBUG("Request sent, wait for response ` `", req.verb(), req.target());
        auto space = req.get_remain_space();
        auto &resp = op->resp;

        if (space.second > kMinimalHeadersSize) {
            resp.reset(space.first, space.second, false, sock.release(), true, req.verb());
        } else {
            auto buf = malloc(kMinimalHeadersSize);
            resp.reset((char *)buf, kMinimalHeadersSize, true, sock.release(), true, req.verb());
        }
        if (op->resp.receive_header(tmo.timeout()) != 0) {
            req.reset_status();
            LOG_ERROR_RETURN(0, ROUNDTRIP_NEED_RETRY, "read response header failed");
        }

        op->status_code = resp.status_code();
        LOG_DEBUG("Got response ` ` code=` || content_length=`", req.verb(),
                  req.target(), resp.status_code(), resp.headers.content_length());
        if (m_cookie_jar) m_cookie_jar->get_cookies_from_headers(req.host(), &resp);
        if (resp.status_code() < 400 && resp.status_code() >= 300 && op->follow)
            return redirect(op);
        return ROUNDTRIP_SUCCESS;
    }