peake100/rogerRabbit-go

package internal

import streadway "github.com/streadway/amqp"

// Delivery captures the fields for a previously delivered message resident in
// a queue to be delivered by the server to a consumer from Channel.Consume or
// Channel.Get.
//
// --
//
// ROGER NOTE: As streadway/amqp.Delivery, but with additional data specifying the tag
// offset that was applied to this delivery to create a continuous, non-doubled
// delivery tags across disconnect.
type Delivery struct {
    // The original delivery from the underlying channel, embedded in our struct so it
    // can act as a drop-in replacement
    streadway.Delivery

    // TagOffset is the offset applied to our Delivery tag to create a continuous stream
    // of delivery tag values across disconnects.
    TagOffset uint64
}

// NewDelivery created a new Delivery object from an original source streadway.Delivery
// value plus our new Acknowledger.
func NewDelivery(
    orig streadway.Delivery,
    acknowledger streadway.Acknowledger,
) Delivery {
    // Swap out the acknowledger for our robust channel so ack, nack, and reject
    // methods call our robust channel rather than the underlying one.
    orig.Acknowledger = acknowledger

    // Embed the original delivery
    delivery := Delivery{
        Delivery:  orig,
        TagOffset: 0,
    }

    return delivery
}