minio/pkg/s3select/json/record.go

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/*
* 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("{}"),
}
}