make notification as separate package (#5294)

* Remove old notification files

* Add net package

* Add event package

* Modify minio to take new notification system

pkg/event/arn.go

@@ -0,0 +1,83 @@
+/*
+ * 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 event
+
+import (
+	"encoding/xml"
+	"strings"
+)
+
+// ARN - SQS resource name representation.
+type ARN struct {
+	TargetID
+	region string
+}
+
+// String - returns string representation.
+func (arn ARN) String() string {
+	if arn.TargetID.ID == "" && arn.TargetID.Name == "" && arn.region == "" {
+		return ""
+	}
+
+	return "arn:minio:sqs:" + arn.region + ":" + arn.TargetID.String()
+}
+
+// MarshalXML - encodes to XML data.
+func (arn ARN) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
+	return e.EncodeElement(arn.String(), start)
+}
+
+// UnmarshalXML - decodes XML data.
+func (arn *ARN) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
+	var s string
+	if err := d.DecodeElement(&s, &start); err != nil {
+		return err
+	}
+
+	parsedARN, err := parseARN(s)
+	if err != nil {
+		return err
+	}
+
+	*arn = *parsedARN
+	return nil
+}
+
+// parseARN - parses string to ARN.
+func parseARN(s string) (*ARN, error) {
+	// ARN must be in the format of arn:minio:sqs:<REGION>:<ID>:<TYPE>
+	if !strings.HasPrefix(s, "arn:minio:sqs:") {
+		return nil, &ErrInvalidARN{s}
+	}
+
+	tokens := strings.Split(s, ":")
+	if len(tokens) != 6 {
+		return nil, &ErrInvalidARN{s}
+	}
+
+	if tokens[4] == "" || tokens[5] == "" {
+		return nil, &ErrInvalidARN{s}
+	}
+
+	return &ARN{
+		region: tokens[3],
+		TargetID: TargetID{
+			ID:   tokens[4],
+			Name: tokens[5],
+		},
+	}, nil
+}