Method executeImpl

src/Functions/formatRow.cpp:60–105

    ColumnNumbers getArgumentsThatAreAlwaysConstant() const override { return {0}; }

    ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t input_rows_count) const override
    {
        auto col_str = ColumnString::create();
        ColumnString::Chars & vec = col_str->getChars();
        WriteBufferFromVector<ColumnString::Chars> buffer(vec);
        ColumnString::Offsets & offsets = col_str->getOffsets();
        offsets.resize(input_rows_count);

        Block arg_columns;

        size_t arguments_size = arguments.size();
        for (size_t i = 1; i < arguments_size; ++i)
        {
            auto argument_column = arguments[i];
            argument_column.name = arguments_column_names[i];
            arg_columns.insert(std::move(argument_column));
        }

        materializeBlockInplace(arg_columns);
        auto out = FormatFactory::instance().getOutputFormat(format_name, buffer, arg_columns, context, format_settings);

        /// This function make sense only for row output formats.
        auto * row_output_format = dynamic_cast<IRowOutputFormat *>(out.get());
        if (!row_output_format)
            throw Exception(ErrorCodes::BAD_ARGUMENTS,
                            "Cannot turn rows into a {} format strings. {} function supports only row output formats",
                            format_name, getName());

        auto columns = arg_columns.getColumns();
        for (size_t i = 0; i != input_rows_count; ++i)
        {
            row_output_format->writePrefixIfNeeded();
            row_output_format->writeRow(columns, i);
            row_output_format->finalize();
            if (no_newline)
            {
                if (buffer.position() != buffer.buffer().begin() && buffer.position()[-1] == '\n')
                    --buffer.position();
            }

            offsets[i] = buffer.count();
            row_output_format->resetFormatter();
        }

        return col_str;
    }

private:
    const char * function_name;