chore: import upstream snapshot with attribution

internal/util/orderedmap/orderedmap.go

@@ -0,0 +1,62 @@
+// Copyright 2025 Google LLC
+//
+// 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 orderedmap
+
+import (
+	"bytes"
+	"encoding/json"
+)
+
+// Column represents a single column in a row.
+type Column struct {
+	Name  string
+	Value any
+}
+
+// Row represents a row of data with columns in a specific order.
+type Row struct {
+	Columns []Column
+}
+
+// Add adds a new column to the row.
+func (r *Row) Add(name string, value any) {
+	r.Columns = append(r.Columns, Column{Name: name, Value: value})
+}
+
+// MarshalJSON implements the json.Marshaler interface for the Row struct.
+// It marshals the row into a JSON object, preserving the order of the columns.
+func (r Row) MarshalJSON() ([]byte, error) {
+	var buf bytes.Buffer
+	buf.WriteString("{")
+	for i, col := range r.Columns {
+		if i > 0 {
+			buf.WriteString(",")
+		}
+		// Marshal the key
+		key, err := json.Marshal(col.Name)
+		if err != nil {
+			return nil, err
+		}
+		buf.Write(key)
+		buf.WriteString(":")
+		// Marshal the value
+		val, err := json.Marshal(col.Value)
+		if err != nil {
+			return nil, err
+		}
+		buf.Write(val)
+	}
+	buf.WriteString("}")
+	return buf.Bytes(), nil
+}