func createOrderedCodeKey()

in cassandra-bigtable-migration-tools/cassandra-bigtable-proxy/translator/utils.go [2099:2158]
46 lines of code
11 McCabe index (conditional complexity)

func createOrderedCodeKey(primaryKeys []schemaMapping.Column, values map[string]interface{}, encodeIntValuesWithBigEndian bool) ([]byte, error) {
	fixedValues, err := convertAllValuesToRowKeyType(primaryKeys, values)
	if err != nil {
		return nil, err
	}

	var result []byte
	var trailingEmptyFields []byte
	for i, pmk := range primaryKeys {
		if i != pmk.PkPrecedence-1 {
			return nil, fmt.Errorf("wrong order for primary keys")
		}
		value, exists := fixedValues[pmk.ColumnName]
		if !exists {
			return nil, fmt.Errorf("missing primary key `%s`", pmk.ColumnName)
		}

		var orderEncodedField []byte
		var err error
		switch v := value.(type) {
		case int64:
			orderEncodedField, err = encodeInt64Key(v, encodeIntValuesWithBigEndian)
			if err != nil {
				return nil, err
			}
		case string:
			orderEncodedField, err = Append(nil, v)
			if err != nil {
				return nil, err
			}
			// the ordered code library always appends a delimiter to strings, but we have custom delimiter logic so remove it
			orderEncodedField = orderEncodedField[:len(orderEncodedField)-2]
		default:
			return nil, fmt.Errorf("unsupported row key type %T", value)
		}

		// Omit trailing empty fields from the encoding. We achieve this by holding
		// them back in a separate buffer until we hit a non-empty field.
		if len(orderEncodedField) == 0 {
			trailingEmptyFields = append(trailingEmptyFields, kOrderedCodeEmptyField...)
			trailingEmptyFields = append(trailingEmptyFields, kOrderedCodeDelimiter...)
			continue
		}

		if len(result) != 0 {
			result = append(result, kOrderedCodeDelimiter...)
		}

		// Since this field is non-empty, any empty fields we held back are not
		// trailing and should not be omitted. Add them in before appending the
		// latest field. Note that they will correctly end with a delimiter.
		result = append(result, trailingEmptyFields...)
		trailingEmptyFields = nil

		// Finally, append the non-empty field
		result = append(result, orderEncodedField...)
	}

	return result, nil
}