SQL select query for CSV/JSON (#6648)

select * , select column names have been implemented for CSV.
select * is implemented for JSON.

pkg/s3select/format/select.go

@@ -0,0 +1,63 @@
+/*
+ * Minio Cloud Storage, (C) 2018 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 format
+
+import "encoding/xml"
+
+// Select Interface helper methods, implementing features needed for
+// https://docs.aws.amazon.com/AmazonS3/latest/API/RESTObjectSELECTContent.html
+type Select interface {
+	Type() Type
+	Read() (map[string]interface{}, error)
+	Header() []string
+	HasHeader() bool
+	OutputFieldDelimiter() string
+	UpdateBytesProcessed(record map[string]interface{})
+	Expression() string
+	UpdateBytesReturned(int64)
+	CreateStatXML() (string, error)
+	CreateProgressXML() (string, error)
+	ColNameErrs(columnNames []string) error
+	Progress() bool
+}
+
+// Progress represents a struct that represents the format for XML of the
+// progress messages
+type Progress struct {
+	XMLName        xml.Name `xml:"Progress" json:"-"`
+	BytesScanned   int64    `xml:"BytesScanned"`
+	BytesProcessed int64    `xml:"BytesProcessed"`
+	BytesReturned  int64    `xml:"BytesReturned"`
+}
+
+// Stats represents a struct that represents the format for XML of the stat
+// messages
+type Stats struct {
+	XMLName        xml.Name `xml:"Stats" json:"-"`
+	BytesScanned   int64    `xml:"BytesScanned"`
+	BytesProcessed int64    `xml:"BytesProcessed"`
+	BytesReturned  int64    `xml:"BytesReturned"`
+}
+
+// Type different types of support data format types.
+type Type string
+
+// Different data format types.
+const (
+	JSON Type = "json"
+	CSV  Type = "csv"
+)