Refactor s3select to support parquet. (#7023)

Also handle pretty formatted JSON documents.

pkg/s3select/json/record.go

@@ -0,0 +1,107 @@
+/*
+ * Minio Cloud Storage, (C) 2019 Minio, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package json
+
+import (
+	"bytes"
+	"encoding/csv"
+	"fmt"
+	"strings"
+
+	"github.com/minio/minio/pkg/s3select/sql"
+	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
+)
+
+// Record - is JSON record.
+type Record struct {
+	data []byte
+}
+
+// Get - gets the value for a column name.
+func (r *Record) Get(name string) (*sql.Value, error) {
+	result := gjson.GetBytes(r.data, name)
+	switch result.Type {
+	case gjson.False:
+		return sql.NewBool(false), nil
+	case gjson.Number:
+		return sql.NewFloat(result.Float()), nil
+	case gjson.String:
+		return sql.NewString(result.String()), nil
+	case gjson.True:
+		return sql.NewBool(true), nil
+	}
+
+	return nil, fmt.Errorf("unsupported gjson value %v; %v", result, result.Type)
+}
+
+// Set - sets the value for a column name.
+func (r *Record) Set(name string, value *sql.Value) (err error) {
+	var v interface{}
+	switch value.Type() {
+	case sql.Bool:
+		v = value.BoolValue()
+	case sql.Int:
+		v = value.IntValue()
+	case sql.Float:
+		v = value.FloatValue()
+	case sql.String:
+		v = value.StringValue()
+	default:
+		return fmt.Errorf("unsupported sql value %v and type %v", value, value.Type())
+	}
+
+	name = strings.Replace(name, "*", "__ALL__", -1)
+	r.data, err = sjson.SetBytes(r.data, name, v)
+	return err
+}
+
+// MarshalCSV - encodes to CSV data.
+func (r *Record) MarshalCSV(fieldDelimiter rune) ([]byte, error) {
+	var csvRecord []string
+	result := gjson.ParseBytes(r.data)
+	result.ForEach(func(key, value gjson.Result) bool {
+		csvRecord = append(csvRecord, value.String())
+		return true
+	})
+
+	buf := new(bytes.Buffer)
+	w := csv.NewWriter(buf)
+	w.Comma = fieldDelimiter
+	if err := w.Write(csvRecord); err != nil {
+		return nil, err
+	}
+	w.Flush()
+	if err := w.Error(); err != nil {
+		return nil, err
+	}
+
+	data := buf.Bytes()
+	return data[:len(data)-1], nil
+}
+
+// MarshalJSON - encodes to JSON data.
+func (r *Record) MarshalJSON() ([]byte, error) {
+	return r.data, nil
+}
+
+// NewRecord - creates new empty JSON record.
+func NewRecord() *Record {
+	return &Record{
+		data: []byte("{}"),
+	}
+}