Function getSingleImpl

pointer.go:484–542

(node any, decodedToken string, nameProvider NameProvider)

}

func getSingleImpl(node any, decodedToken string, nameProvider NameProvider) (any, reflect.Kind, error) {
	rValue := reflect.Indirect(reflect.ValueOf(node))
	kind := rValue.Kind()
	if isNil(node) {
		return nil, kind, fmt.Errorf("nil value has no field %q: %w", decodedToken, ErrPointer)
	}

	switch typed := node.(type) {
	case JSONPointable:
		r, err := typed.JSONLookup(decodedToken)
		if err != nil {
			return nil, kind, err
		}
		return r, kind, nil
	case *any: // case of a pointer to interface, that is not resolved by reflect.Indirect
		return getSingleImpl(*typed, decodedToken, nameProvider)
	}

	switch kind {
	case reflect.Struct:
		nm, ok := nameProvider.GetGoNameForType(rValue.Type(), decodedToken)
		if !ok {
			return nil, kind, fmt.Errorf("object has no field %q: %w", decodedToken, ErrPointer)
		}

		fld := rValue.FieldByName(nm)

		return fld.Interface(), kind, nil

	case reflect.Map:
		kv := reflect.ValueOf(decodedToken)
		mv := rValue.MapIndex(kv)

		if mv.IsValid() {
			return mv.Interface(), kind, nil
		}

		return nil, kind, errNoKey(decodedToken)

	case reflect.Slice:
		if decodedToken == dashToken {
			return nil, kind, errDashOnGet()
		}
		tokenIndex, err := strconv.Atoi(decodedToken)
		if err != nil {
			return nil, kind, errors.Join(err, ErrPointer)
		}
		sLength := rValue.Len()
		if tokenIndex < 0 || tokenIndex >= sLength {
			return nil, kind, errOutOfBounds(sLength, tokenIndex)
		}

		elem := rValue.Index(tokenIndex)
		return elem.Interface(), kind, nil

	default:
		return nil, kind, errInvalidReference(decodedToken)
	}