// Copyright (c) 2015-2021 MinIO, Inc.//// This file is part of MinIO Object Storage stack//// This program is free software: you can redistribute it and/or modify// it under the terms of the GNU Affero General Public License as published by// the Free Software Foundation, either version 3 of the License, or// (at your option) any later version.//// This program is distributed in the hope that it will be useful// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the// GNU Affero General Public License for more details.//// You should have received a copy of the GNU Affero General Public License// along with this program.  If not, see <http://www.gnu.org/licenses/>. package csv import (	"encoding/json"	"errors"	"fmt"	"io"	"strconv"	"strings" 	"github.com/bcicen/jstream"	csv "github.com/minio/csvparser"	"github.com/minio/minio/internal/s3select/sql") // Record - is a CSV record.type Record struct {	columnNames  []string	csvRecord    []string	nameIndexMap map[string]int64} // Get - gets the value for a column name. CSV fields do not have any// defined type (other than the default string). So this function// always returns fields using sql.FromBytes so that the type// specified/implied by the query can be used, or can be automatically// converted based on the query.func (r *Record) Get(name string) (*sql.Value, error) {	index, found := r.nameIndexMap[name]	if !found {		// Check if index.		if strings.HasPrefix(name, "_") {			idx, err := strconv.Atoi(strings.TrimPrefix(name, "_"))			if err != nil {				return nil, fmt.Errorf("column %v not found", name)			}			// The position count starts at 1.			idx--			if idx >= len(r.csvRecord) || idx < 0 {				// If field index > number of columns, return null				return sql.FromNull(), nil			}			return sql.FromBytes([]byte(r.csvRecord[idx])), nil		}		// TODO: Return Missing?		return nil, fmt.Errorf("column %v not found", name)	} 	if index >= int64(len(r.csvRecord)) {		// No value found for column 'name', hence return null		// value		return sql.FromNull(), nil	} 	return sql.FromBytes([]byte(r.csvRecord[index])), nil} // Set - sets the value for a column name.func (r *Record) Set(name string, value *sql.Value) (sql.Record, error) {	r.columnNames = append(r.columnNames, name)	r.csvRecord = append(r.csvRecord, value.CSVString())	return r, nil} // Reset data in record.func (r *Record) Reset() {	if len(r.columnNames) > 0 {		r.columnNames = r.columnNames[:0]	}	if len(r.csvRecord) > 0 {		r.csvRecord = r.csvRecord[:0]	}	for k := range r.nameIndexMap {		delete(r.nameIndexMap, k)	}} // Clone the record.func (r *Record) Clone(dst sql.Record) sql.Record {	other, ok := dst.(*Record)	if !ok {		other = &Record{}	}	if len(other.columnNames) > 0 {		other.columnNames = other.columnNames[:0]	}	if len(other.csvRecord) > 0 {		other.csvRecord = other.csvRecord[:0]	}	other.columnNames = append(other.columnNames, r.columnNames...)	other.csvRecord = append(other.csvRecord, r.csvRecord...)	return other} // WriteCSV - encodes to CSV data.func (r *Record) WriteCSV(writer io.Writer, opts sql.WriteCSVOpts) error {	w := csv.NewWriter(writer)	w.Comma = opts.FieldDelimiter	w.AlwaysQuote = opts.AlwaysQuote	w.Quote = opts.Quote	w.QuoteEscape = opts.QuoteEscape	if err := w.Write(r.csvRecord); err != nil {		return err	}	w.Flush()	return w.Error()} // WriteJSON - encodes to JSON data.func (r *Record) WriteJSON(writer io.Writer) error {	var kvs jstream.KVS = make([]jstream.KV, len(r.columnNames))	for i := 0; i < len(r.columnNames); i++ {		kvs[i] = jstream.KV{Key: r.columnNames[i], Value: r.csvRecord[i]}	}	return json.NewEncoder(writer).Encode(kvs)} // Raw - returns the underlying data with format info.func (r *Record) Raw() (sql.SelectObjectFormat, interface{}) {	return sql.SelectFmtCSV, r} // Replace - is not supported for CSVfunc (r *Record) Replace(_ interface{}) error {	return errors.New("Replace is not supported for CSV")} // NewRecord - creates new CSV record.func NewRecord() *Record {	return &Record{}}