OP#792 initial commit after fork

internal/s3select/csv/record.go

@@ -0,0 +1,148 @@
+// 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"
+
+	csv "github.com/minio/csvparser"
+	"github.com/minio/minio/internal/s3select/jstream"
+	"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 after, ok := strings.CutPrefix(name, "_"); ok {
+			idx, err := strconv.Atoi(after)
+			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]
+	}
+	clear(r.nameIndexMap)
+}
+
+// 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, 0, len(r.columnNames))
+	for i, cn := range r.columnNames {
+		if i < len(r.csvRecord) {
+			kvs = append(kvs, jstream.KV{Key: cn, Value: r.csvRecord[i]})
+		}
+	}
+	return json.NewEncoder(writer).Encode(kvs)
+}
+
+// Raw - returns the underlying data with format info.
+func (r *Record) Raw() (sql.SelectObjectFormat, any) {
+	return sql.SelectFmtCSV, r
+}
+
+// Replace - is not supported for CSV
+func (r *Record) Replace(_ any) error {
+	return errors.New("Replace is not supported for CSV")
+}
+
+// NewRecord - creates new CSV record.
+func NewRecord() *Record {
+	return &Record{}
+}