Function checkValidSrc

protocol/validation/validation.go:323–386

(vstate *validationState, vs *bc.ValueSource)

}

func checkValidSrc(vstate *validationState, vs *bc.ValueSource) error {
	if vs == nil {
		return errors.Wrap(errMissingField, "empty value source")
	}
	if vs.Ref == nil {
		return errors.Wrap(errMissingField, "missing ref on value source")
	}
	if vs.Value == nil || vs.Value.AssetId == nil {
		return errors.Wrap(errMissingField, "missing value on value source")
	}

	e, ok := vstate.tx.Entries[*vs.Ref]
	if !ok {
		return errors.Wrapf(bc.ErrMissingEntry, "entry for value source %x not found", vs.Ref.Bytes())
	}
	vstate2 := *vstate
	vstate2.entryID = *vs.Ref
	err := checkValid(&vstate2, e)
	if err != nil {
		return errors.Wrap(err, "checking value source")
	}

	var dest *bc.ValueDestination
	switch ref := e.(type) {
	case *bc.Issuance:
		if vs.Position != 0 {
			return errors.Wrapf(errPosition, "invalid position %d for issuance source", vs.Position)
		}
		dest = ref.WitnessDestination

	case *bc.Spend:
		if vs.Position != 0 {
			return errors.Wrapf(errPosition, "invalid position %d for spend source", vs.Position)
		}
		dest = ref.WitnessDestination

	case *bc.Mux:
		if vs.Position >= uint64(len(ref.WitnessDestinations)) {
			return errors.Wrapf(errPosition, "invalid position %d for %d-destination mux source", vs.Position, len(ref.WitnessDestinations))
		}
		dest = ref.WitnessDestinations[vs.Position]

	default:
		return errors.Wrapf(bc.ErrEntryType, "value source is %T, should be issuance, spend, or mux", e)
	}

	if dest.Ref == nil || *dest.Ref != vstate.entryID {
		return errors.Wrapf(errMismatchedReference, "value source for %x has disagreeing destination %x", vstate.entryID.Bytes(), dest.Ref.Bytes())
	}

	if dest.Position != vstate.sourcePos {
		return errors.Wrapf(errMismatchedPosition, "value source position %d disagrees with %d", dest.Position, vstate.sourcePos)
	}

	eq, err := dest.Value.Equal(vs.Value)
	if err != nil {
		return errors.Sub(errMissingField, err)
	}