if len(c.Rules) == 0 {
		return errReplicationNoRule
	}

	// Validate all the rules in the replication config
	targetMap := make(map[string]struct{})
	priorityMap := make(map[string]struct{})
	var legacyArn bool
	for _, r := range c.Rules {
		if _, ok := targetMap[r.Destination.Bucket]; !ok {
			targetMap[r.Destination.Bucket] = struct{}{}
		}
		if err := r.Validate(bucket, sameTarget); err != nil {
			return err
		}

	defer list.RUnlock()

	keys := make([]ARN, 0, len(list.targets))
	for k := range list.targets {
		keys = append(keys, k.ToARN(region))
	}

	return keys
}

// TargetMap - returns available targets.
func (list *TargetList) TargetMap() map[TargetID]Target {
	list.RLock()
	defer list.RUnlock()

	ntargets := make(map[TargetID]Target, len(list.targets))
	maps.Copy(ntargets, list.targets)
	return ntargets
}

// GetARNList - returns available ARNs.
func (evnot *EventNotifier) GetARNList() []string {
	arns := []string{}
	if evnot == nil {
		return arns
	}
	region := globalSite.Region()
	for targetID := range evnot.targetList.TargetMap() {
		// httpclient target is part of ListenNotification
		// which doesn't need to be listed as part of the ARN list
		// This list is only meant for external targets, filter
		// this out pro-actively.

}

func (list *TargetList) get(id TargetID) (Target, bool) {
	list.RLock()
	defer list.RUnlock()

	target, ok := list.targets[id]
	return target, ok
}

// TargetMap - returns available targets.
func (list *TargetList) TargetMap() map[TargetID]Target {
	list.RLock()
	defer list.RUnlock()

	ntargets := make(map[TargetID]Target, len(list.targets))
	maps.Copy(ntargets, list.targets)
	return ntargets
}