Method readRow

src/Processors/Formats/Impl/JSONEachRowRowInputFormat.cpp:213–254

bool JSONEachRowRowInputFormat::readRow(MutableColumns & columns, RowReadExtension & ext)
{
    if (!allow_new_rows)
        return false;
    skipWhitespaceIfAny(*in);

    bool is_first_row = getRowNum() == 0;
    if (checkEndOfData(is_first_row))
        return false;

    size_t num_columns = columns.size();
    total_columns = num_columns;
    seen_columns_count = 0;

    read_columns.assign(num_columns, false);
    seen_columns.assign(num_columns, false);

    nested_prefix_length = 0;
    readRowStart(columns);
    readJSONObject(columns);

    const auto & header = getPort().getHeader();
    /// Fill non-visited columns with the default values.
    for (size_t i = 0; i < num_columns; ++i)
        if (!seen_columns[i])
        {
            const auto & type = header.getByPosition(i).type;
            if (format_settings.force_null_for_omitted_fields && !isNullableOrLowCardinalityNullable(type))
                throw Exception(ErrorCodes::TYPE_MISMATCH, "Cannot insert NULL value into a column `{}` of type '{}'", columnName(i), type->getName());
            type->insertDefaultInto(*columns[i]);
        }


    /// Return info about defaults set.
    /// If defaults_for_omitted_fields is set to 0, we should just leave already inserted defaults.
    if (format_settings.defaults_for_omitted_fields)
        ext.read_columns = read_columns;
    else
        ext.read_columns.assign(read_columns.size(), true);

    return true;
}

bool JSONEachRowRowInputFormat::checkEndOfData(bool is_first_row)
{