refactor cmd/config to internal

cmd/config/internal/inpututil/inpututil.go

@@ -0,0 +1,42 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package inpututil
+
+import (
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+)
+
+type MapInputsEFn func(*yaml.RNode, yaml.ResourceMeta) error
+
+func MapInputsE(inputs []*yaml.RNode, fn MapInputsEFn) error {
+	for i := range inputs {
+		meta, err := inputs[i].GetMeta()
+		if err != nil {
+			return err
+		}
+		if err := fn(inputs[i], meta); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+type MapInputsFn func(*yaml.RNode, yaml.ResourceMeta) ([]*yaml.RNode, error)
+
+//  runs the function against each input Resource, providing the parsed metadata
+func MapInputs(inputs []*yaml.RNode, fn MapInputsFn) ([]*yaml.RNode, error) {
+	var outputs []*yaml.RNode
+	for i := range inputs {
+		meta, err := inputs[i].GetMeta()
+		if err != nil {
+			return nil, err
+		}
+		o, err := fn(inputs[i], meta)
+		if err != nil {
+			return nil, err
+		}
+		outputs = append(outputs, o...)
+	}
+	return outputs, nil
+}