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minio/pkg/s3select/json/record.go

167 lines
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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 (
"encoding/csv"
"encoding/json"
"errors"
"fmt"
"io"
"strings"
"github.com/bcicen/jstream"
"github.com/minio/minio/pkg/s3select/sql"
)
// RawJSON is a byte-slice that contains valid JSON
type RawJSON []byte
// MarshalJSON instance for []byte that assumes that byte-slice is
// already serialized JSON
func (b RawJSON) MarshalJSON() ([]byte, error) {
return b, nil
}
// Record - is JSON record.
type Record struct {
// Used in Set(), Marshal*()
KVS jstream.KVS
SelectFormat sql.SelectObjectFormat
}
// Get - gets the value for a column name.
func (r *Record) Get(name string) (*sql.Value, error) {
// Get is implemented directly in the sql package.
return nil, errors.New("not implemented here")
}
// Reset the record.
func (r *Record) Reset() {
if len(r.KVS) > 0 {
r.KVS = r.KVS[:0]
}
}
// Clone the record and if possible use the destination provided.
func (r *Record) Clone(dst sql.Record) sql.Record {
other, ok := dst.(*Record)
if !ok {
other = &Record{}
}
if len(other.KVS) > 0 {
other.KVS = other.KVS[:0]
}
other.KVS = append(other.KVS, r.KVS...)
return other
}
// Set - sets the value for a column name.
func (r *Record) Set(name string, value *sql.Value) error {
var v interface{}
if b, ok := value.ToBool(); ok {
v = b
} else if f, ok := value.ToFloat(); ok {
v = f
} else if i, ok := value.ToInt(); ok {
v = i
} else if t, ok := value.ToTimestamp(); ok {
v = sql.FormatSQLTimestamp(t)
} else if s, ok := value.ToString(); ok {
v = s
} else if value.IsNull() {
v = nil
} else if b, ok := value.ToBytes(); ok {
// This can either be raw json or a CSV value.
// Only treat objects and arrays as JSON.
if len(b) > 0 && (b[0] == '{' || b[0] == '[') {
v = RawJSON(b)
} else {
v = string(b)
}
} else if arr, ok := value.ToArray(); ok {
v = arr
} else {
return fmt.Errorf("unsupported sql value %v and type %v", value, value.GetTypeString())
}
name = strings.Replace(name, "*", "__ALL__", -1)
r.KVS = append(r.KVS, jstream.KV{Key: name, Value: v})
return nil
}
// WriteCSV - encodes to CSV data.
func (r *Record) WriteCSV(writer io.Writer, fieldDelimiter rune) error {
var csvRecord []string
for _, kv := range r.KVS {
var columnValue string
switch val := kv.Value.(type) {
case bool, float64, int64, string:
columnValue = fmt.Sprintf("%v", val)
case nil:
columnValue = ""
case RawJSON:
columnValue = string([]byte(val))
case []interface{}:
b, err := json.Marshal(val)
if err != nil {
return err
}
columnValue = string(b)
default:
return fmt.Errorf("Cannot marshal unhandled type: %T", kv.Value)
}
csvRecord = append(csvRecord, columnValue)
}
w := csv.NewWriter(writer)
w.Comma = fieldDelimiter
if err := w.Write(csvRecord); err != nil {
return err
}
w.Flush()
if err := w.Error(); err != nil {
return err
}
return nil
}
// Raw - returns the underlying representation.
func (r *Record) Raw() (sql.SelectObjectFormat, interface{}) {
return r.SelectFormat, r.KVS
}
// WriteJSON - encodes to JSON data.
func (r *Record) WriteJSON(writer io.Writer) error {
return json.NewEncoder(writer).Encode(r.KVS)
}
// Replace the underlying buffer of json data.
func (r *Record) Replace(k jstream.KVS) error {
r.KVS = k
return nil
}
// NewRecord - creates new empty JSON record.
func NewRecord(f sql.SelectObjectFormat) *Record {
return &Record{
KVS: jstream.KVS{},
SelectFormat: f,
}
}