internal bool SendDelivery()

in src/AmqpLink.cs [893:979]
77 lines of code
16 McCabe index (conditional complexity)

        internal bool SendDelivery(Delivery delivery)
        {
            bool settled = delivery.Settled;
            bool more = true;
            while (more)
            {
                bool firstTransfer = delivery.BytesTransfered == 0;
                Transfer transfer = new Transfer();
                transfer.Handle = this.LocalHandle;
                transfer.More = more;
                transfer.Aborted = delivery.Aborted;
                transfer.Resume = delivery.Resume;
                if (firstTransfer)
                {
                    transfer.DeliveryId = uint.MaxValue;    // reserve the space first
                    transfer.DeliveryTag = delivery.DeliveryTag;
                    transfer.MessageFormat = delivery.MessageFormat ?? AmqpConstants.AmqpMessageFormat;
                    transfer.Batchable = delivery.Batchable;
                    transfer.State = delivery.State;
                    if (settled)
                    {
                        transfer.Settled = true;
                    }

                    if (delivery.TxnId.Array != null)
                    {
                        transfer.State = new TransactionalState() { TxnId = delivery.TxnId };
                    }
                }

                ByteBuffer payload = null;
                if (delivery.Resume && delivery.State.IsTerminal())
                {
                    more = false;
                    transfer.More = false;
                }
                else
                {
                    uint maxFrameSize = this.MaxFrameSize == uint.MaxValue ? AmqpConstants.DefaultMaxFrameSize : this.MaxFrameSize;
                    int overhead = Frame.HeaderSize + transfer.EncodeSize;
                    if (overhead > maxFrameSize)
                    {
                        throw new AmqpException(AmqpErrorCode.FrameSizeTooSmall, null);
                    }

                    int payloadSize = (int)maxFrameSize - overhead;
                    payload = delivery.GetPayload(payloadSize, out more);
                    transfer.More = more;

                    if (payload == null)
                    {
                        if (firstTransfer)
                        {
                            throw new AmqpException(AmqpErrorCode.NotAllowed, AmqpResources.AmqpEmptyMessageNotAllowed);
                        }

                        Fx.Assert(!more, "More flag is set but a null payload is returned.");
                        break;
                    }
                }

                if (!this.Session.TrySendTransfer(firstTransfer ? delivery : null, transfer, payload))
                {
                    payload?.Dispose();
                    more = true;
                    break;
                }

                if (payload != null)
                {
                    delivery.CompletePayload(payload.Length);
                }
            }

            if (!more)
            {
                AmqpTrace.Provider.AmqpSentMessage(this, delivery.DeliveryId.Value, delivery.BytesTransfered);

                if (delivery.Settled)
                {
                    delivery.State = AmqpConstants.AcceptedOutcome;
                    this.OnDisposeDeliveryInternal(delivery);
                }
            }

            return !more;
        }