chore: import upstream snapshot with attribution

store/postgres/metadata.go

@@ -0,0 +1,61 @@
+// Copyright 2020 Asim Aslam
+//
+// 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
+//
+//     https://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.
+//
+// Original source: github.com/micro/go-plugins/v3/store/cockroach/metadata.go
+
+package postgres
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"errors"
+)
+
+// https://github.com/upper/db/blob/master/postgresql/custom_types.go#L43
+type Metadata map[string]interface{}
+
+// Scan satisfies the sql.Scanner interface.
+func (m *Metadata) Scan(src interface{}) error {
+	source, ok := src.([]byte)
+	if !ok {
+		return errors.New("type assertion .([]byte) failed")
+	}
+
+	var i interface{}
+	err := json.Unmarshal(source, &i)
+	if err != nil {
+		return err
+	}
+
+	*m, ok = i.(map[string]interface{})
+	if !ok {
+		return errors.New("type assertion .(map[string]interface{}) failed")
+	}
+
+	return nil
+}
+
+// Value satisfies the driver.Valuer interface.
+func (m Metadata) Value() (driver.Value, error) {
+	j, err := json.Marshal(m)
+	return j, err
+}
+
+func toMetadata(m *Metadata) map[string]interface{} {
+	md := make(map[string]interface{})
+	for k, v := range *m {
+		md[k] = v
+	}
+	return md
+}