Add utility package for dealing with common map types

hack/.linted_packages

@@ -196,3 +196,4 @@ test/integration/openshift
 test/soak/cauldron
 test/soak/serve_hostnames
 third_party/forked/golang/expansion
+pkg/util/maps

pkg/util/maps/doc.go

+/*
+Copyright 2016 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 maps has common methods for dealing with common map types.
+package maps

pkg/util/maps/string.go

+/*
+Copyright 2016 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 maps
+
+// CopySS makes a shallow copy of a map.
+func CopySS(m map[string]string) map[string]string {
+	if m == nil {
+		return nil
+	}
+	copy := make(map[string]string, len(m))
+	for k, v := range m {
+		copy[k] = v
+	}
+	return copy
+}