Added conversions to/from NamespacedName

Also renamed file to something more on-point.

staging/src/k8s.io/client-go/tools/cache/object-names.go

@@ -16,6 +16,10 @@ limitations under the License.
 
 package cache
 
+import (
+	"k8s.io/apimachinery/pkg/types"
+)
+
 // ObjectName is a reference to an object of some implicit kind
 type ObjectName struct {
 	Namespace string
@@ -34,6 +38,7 @@ func (objName ObjectName) Parts() (namespace, name string) {
 
 // String returns the standard string encoding,
 // which is designed to match the historical behavior of MetaNamespaceKeyFunc.
+// Note this behavior is different from the String method of types.NamespacedName.
 func (objName ObjectName) String() string {
 	if len(objName.Namespace) > 0 {
 		return objName.Namespace + "/" + objName.Name
@@ -48,3 +53,13 @@ func ParseObjectName(str string) (ObjectName, error) {
 	objName.Namespace, objName.Name, err = SplitMetaNamespaceKey(str)
 	return objName, err
 }
+
+// NamespacedNameAsObjectName rebrands the given NamespacedName as an ObjectName
+func NamespacedNameAsObjectName(nn types.NamespacedName) ObjectName {
+	return NewObjectName(nn.Namespace, nn.Name)
+}
+
+// AsNamespacedName rebrands as a NamespacedName
+func (objName ObjectName) AsNamespacedName() types.NamespacedName {
+	return types.NamespacedName{Namespace: objName.Namespace, Name: objName.Name}
+}

staging/src/k8s.io/client-go/tools/cache/object-names_test.go

@@ -0,0 +1,59 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+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 cache
+
+import (
+	"math/rand"
+	"strings"
+	"testing"
+)
+
+func TestObjectNames(t *testing.T) {
+	chars := "abcdefghi/"
+	for count := 1; count <= 100; count++ {
+		var encodedB strings.Builder
+		for index := 0; index < 10; index++ {
+			encodedB.WriteByte(chars[rand.Intn(len(chars))])
+		}
+		encodedS := encodedB.String()
+		parts := strings.Split(encodedS, "/")
+		on, err := ParseObjectName(encodedS)
+		expectError := len(parts) > 2
+		if expectError != (err != nil) {
+			t.Errorf("Wrong error; expected=%v, got=%v", expectError, err)
+		}
+		if expectError || err != nil {
+			continue
+		}
+		var expectedObjectName ObjectName
+		if len(parts) == 2 {
+			expectedObjectName = ObjectName{Namespace: parts[0], Name: parts[1]}
+		} else {
+			expectedObjectName = ObjectName{Name: encodedS}
+		}
+		if on != expectedObjectName {
+			t.Errorf("Parse failed, expected=%+v, got=%+v", expectedObjectName, on)
+		}
+		recoded := on.String()
+		if encodedS[0] == '/' {
+			recoded = "/" + recoded
+		}
+		if encodedS != recoded {
+			t.Errorf("Parse().String() was not identity, original=%q, final=%q", encodedS, recoded)
+		}
+	}
+}