Refactor s3select to support parquet. (#7023)

Also handle pretty formatted JSON documents.

pkg/s3select/json/args.go

@@ -0,0 +1,95 @@
+/*
+ * 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/xml"
+	"fmt"
+	"strings"
+)
+
+const (
+	document = "document"
+	lines    = "lines"
+
+	defaultRecordDelimiter = "\n"
+)
+
+// ReaderArgs - represents elements inside <InputSerialization><JSON/> in request XML.
+type ReaderArgs struct {
+	ContentType string `xml:"Type"`
+	unmarshaled bool
+}
+
+// IsEmpty - returns whether reader args is empty or not.
+func (args *ReaderArgs) IsEmpty() bool {
+	return !args.unmarshaled
+}
+
+// UnmarshalXML - decodes XML data.
+func (args *ReaderArgs) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
+	// Make subtype to avoid recursive UnmarshalXML().
+	type subReaderArgs ReaderArgs
+	parsedArgs := subReaderArgs{}
+	if err := d.DecodeElement(&parsedArgs, &start); err != nil {
+		return err
+	}
+
+	parsedArgs.ContentType = strings.ToLower(parsedArgs.ContentType)
+	switch parsedArgs.ContentType {
+	case document, lines:
+	default:
+		return errInvalidJSONType(fmt.Errorf("invalid ContentType '%v'", parsedArgs.ContentType))
+	}
+
+	*args = ReaderArgs(parsedArgs)
+	args.unmarshaled = true
+	return nil
+}
+
+// WriterArgs - represents elements inside <OutputSerialization><JSON/> in request XML.
+type WriterArgs struct {
+	RecordDelimiter string `xml:"RecordDelimiter"`
+	unmarshaled     bool
+}
+
+// IsEmpty - returns whether writer args is empty or not.
+func (args *WriterArgs) IsEmpty() bool {
+	return !args.unmarshaled
+}
+
+// UnmarshalXML - decodes XML data.
+func (args *WriterArgs) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
+	// Make subtype to avoid recursive UnmarshalXML().
+	type subWriterArgs WriterArgs
+	parsedArgs := subWriterArgs{}
+	if err := d.DecodeElement(&parsedArgs, &start); err != nil {
+		return err
+	}
+
+	switch len(parsedArgs.RecordDelimiter) {
+	case 0:
+		parsedArgs.RecordDelimiter = defaultRecordDelimiter
+	case 1, 2:
+	default:
+		return fmt.Errorf("invalid RecordDelimiter '%v'", parsedArgs.RecordDelimiter)
+	}
+
+	*args = WriterArgs(parsedArgs)
+	args.unmarshaled = true
+	return nil
+}