func marshalList()

in marshal.go [1590:1646]
51 lines of code
17 McCabe index (conditional complexity)

func marshalList(info TypeInfo, value interface{}) ([]byte, error) {
	listInfo, ok := info.(CollectionType)
	if !ok {
		return nil, marshalErrorf("marshal: can not marshal non collection type into list")
	}

	if value == nil {
		return nil, nil
	} else if _, ok := value.(unsetColumn); ok {
		return nil, nil
	}

	rv := reflect.ValueOf(value)
	t := rv.Type()
	k := t.Kind()
	if k == reflect.Slice && rv.IsNil() {
		return nil, nil
	}

	switch k {
	case reflect.Slice, reflect.Array:
		buf := &bytes.Buffer{}
		n := rv.Len()

		if err := writeCollectionSize(listInfo, n, buf); err != nil {
			return nil, err
		}

		for i := 0; i < n; i++ {
			item, err := Marshal(listInfo.Elem, rv.Index(i).Interface())
			if err != nil {
				return nil, err
			}
			itemLen := len(item)
			// Set the value to null for supported protocols
			if item == nil && listInfo.proto > protoVersion2 {
				itemLen = -1
			}
			if err := writeCollectionSize(listInfo, itemLen, buf); err != nil {
				return nil, err
			}
			buf.Write(item)
		}
		return buf.Bytes(), nil
	case reflect.Map:
		elem := t.Elem()
		if elem.Kind() == reflect.Struct && elem.NumField() == 0 {
			rkeys := rv.MapKeys()
			keys := make([]interface{}, len(rkeys))
			for i := 0; i < len(keys); i++ {
				keys[i] = rkeys[i].Interface()
			}
			return marshalList(listInfo, keys)
		}
	}
	return nil, marshalErrorf("can not marshal %T into %s. Accepted types: slice, array, map[]struct.", value, info)
}