vendor/k8s.io/apimachinery/pkg/api/meta/restmapper.go - voltha-go - Gitiles

 /*
 Copyright 2014 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.
 */

 // TODO: move everything in this file to pkg/api/rest
 package meta

 import (
 	"fmt"
 	"sort"
 	"strings"

 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 )

 // Implements RESTScope interface
 type restScope struct {
 	name RESTScopeName
 }

 func (r *restScope) Name() RESTScopeName {
 	return r.name
 }

 var RESTScopeNamespace = &restScope{
 	name: RESTScopeNameNamespace,
 }

 var RESTScopeRoot = &restScope{
 	name: RESTScopeNameRoot,
 }

 // DefaultRESTMapper exposes mappings between the types defined in a
 // runtime.Scheme. It assumes that all types defined the provided scheme
 // can be mapped with the provided MetadataAccessor and Codec interfaces.
 //
 // The resource name of a Kind is defined as the lowercase,
 // English-plural version of the Kind string.
 // When converting from resource to Kind, the singular version of the
 // resource name is also accepted for convenience.
 //
 // TODO: Only accept plural for some operations for increased control?
 // (`get pod bar` vs `get pods bar`)
 type DefaultRESTMapper struct {
 	defaultGroupVersions []schema.GroupVersion

 	resourceToKind       map[schema.GroupVersionResource]schema.GroupVersionKind
 	kindToPluralResource map[schema.GroupVersionKind]schema.GroupVersionResource
 	kindToScope          map[schema.GroupVersionKind]RESTScope
 	singularToPlural     map[schema.GroupVersionResource]schema.GroupVersionResource
 	pluralToSingular     map[schema.GroupVersionResource]schema.GroupVersionResource
 }

 func (m *DefaultRESTMapper) String() string {
 	return fmt.Sprintf("DefaultRESTMapper{kindToPluralResource=%v}", m.kindToPluralResource)
 }

 var _ RESTMapper = &DefaultRESTMapper{}

 // NewDefaultRESTMapper initializes a mapping between Kind and APIVersion
 // to a resource name and back based on the objects in a runtime.Scheme
 // and the Kubernetes API conventions. Takes a group name, a priority list of the versions
 // to search when an object has no default version (set empty to return an error),
 // and a function that retrieves the correct metadata for a given version.
 func NewDefaultRESTMapper(defaultGroupVersions []schema.GroupVersion) *DefaultRESTMapper {
 	resourceToKind := make(map[schema.GroupVersionResource]schema.GroupVersionKind)
 	kindToPluralResource := make(map[schema.GroupVersionKind]schema.GroupVersionResource)
 	kindToScope := make(map[schema.GroupVersionKind]RESTScope)
 	singularToPlural := make(map[schema.GroupVersionResource]schema.GroupVersionResource)
 	pluralToSingular := make(map[schema.GroupVersionResource]schema.GroupVersionResource)
 	// TODO: verify name mappings work correctly when versions differ

 	return &DefaultRESTMapper{
 		resourceToKind:       resourceToKind,
 		kindToPluralResource: kindToPluralResource,
 		kindToScope:          kindToScope,
 		defaultGroupVersions: defaultGroupVersions,
 		singularToPlural:     singularToPlural,
 		pluralToSingular:     pluralToSingular,
 	}
 }

 func (m *DefaultRESTMapper) Add(kind schema.GroupVersionKind, scope RESTScope) {
 	plural, singular := UnsafeGuessKindToResource(kind)
 	m.AddSpecific(kind, plural, singular, scope)
 }

 func (m *DefaultRESTMapper) AddSpecific(kind schema.GroupVersionKind, plural, singular schema.GroupVersionResource, scope RESTScope) {
 	m.singularToPlural[singular] = plural
 	m.pluralToSingular[plural] = singular

 	m.resourceToKind[singular] = kind
 	m.resourceToKind[plural] = kind

 	m.kindToPluralResource[kind] = plural
 	m.kindToScope[kind] = scope
 }

 // unpluralizedSuffixes is a list of resource suffixes that are the same plural and singular
 // This is only is only necessary because some bits of code are lazy and don't actually use the RESTMapper like they should.
 // TODO eliminate this so that different callers can correctly map to resources.  This probably means updating all
 // callers to use the RESTMapper they mean.
 var unpluralizedSuffixes = []string{
 	"endpoints",
 }

 // UnsafeGuessKindToResource converts Kind to a resource name.
 // Broken. This method only "sort of" works when used outside of this package.  It assumes that Kinds and Resources match
 // and they aren't guaranteed to do so.
 func UnsafeGuessKindToResource(kind schema.GroupVersionKind) ( /*plural*/ schema.GroupVersionResource /*singular*/, schema.GroupVersionResource) {
 	kindName := kind.Kind
 	if len(kindName) == 0 {
 		return schema.GroupVersionResource{}, schema.GroupVersionResource{}
 	}
 	singularName := strings.ToLower(kindName)
 	singular := kind.GroupVersion().WithResource(singularName)

 	for _, skip := range unpluralizedSuffixes {
 		if strings.HasSuffix(singularName, skip) {
 			return singular, singular
 		}
 	}

 	switch string(singularName[len(singularName)-1]) {
 	case "s":
 		return kind.GroupVersion().WithResource(singularName + "es"), singular
 	case "y":
 		return kind.GroupVersion().WithResource(strings.TrimSuffix(singularName, "y") + "ies"), singular
 	}

 	return kind.GroupVersion().WithResource(singularName + "s"), singular
 }

 // ResourceSingularizer implements RESTMapper
 // It converts a resource name from plural to singular (e.g., from pods to pod)
 func (m *DefaultRESTMapper) ResourceSingularizer(resourceType string) (string, error) {
 	partialResource := schema.GroupVersionResource{Resource: resourceType}
 	resources, err := m.ResourcesFor(partialResource)
 	if err != nil {
 		return resourceType, err
 	}

 	singular := schema.GroupVersionResource{}
 	for _, curr := range resources {
 		currSingular, ok := m.pluralToSingular[curr]
 		if !ok {
 			continue
 		}
 		if singular.Empty() {
 			singular = currSingular
 			continue
 		}

 		if currSingular.Resource != singular.Resource {
 			return resourceType, fmt.Errorf("multiple possible singular resources (%v) found for %v", resources, resourceType)
 		}
 	}

 	if singular.Empty() {
 		return resourceType, fmt.Errorf("no singular of resource %v has been defined", resourceType)
 	}

 	return singular.Resource, nil
 }

 // coerceResourceForMatching makes the resource lower case and converts internal versions to unspecified (legacy behavior)
 func coerceResourceForMatching(resource schema.GroupVersionResource) schema.GroupVersionResource {
 	resource.Resource = strings.ToLower(resource.Resource)
 	if resource.Version == runtime.APIVersionInternal {
 		resource.Version = ""
 	}

 	return resource
 }

 func (m *DefaultRESTMapper) ResourcesFor(input schema.GroupVersionResource) ([]schema.GroupVersionResource, error) {
 	resource := coerceResourceForMatching(input)

 	hasResource := len(resource.Resource) > 0
 	hasGroup := len(resource.Group) > 0
 	hasVersion := len(resource.Version) > 0

 	if !hasResource {
 		return nil, fmt.Errorf("a resource must be present, got: %v", resource)
 	}

 	ret := []schema.GroupVersionResource{}
 	switch {
 	case hasGroup && hasVersion:
 		// fully qualified.  Find the exact match
 		for plural, singular := range m.pluralToSingular {
 			if singular == resource {
 				ret = append(ret, plural)
 				break
 			}
 			if plural == resource {
 				ret = append(ret, plural)
 				break
 			}
 		}

 	case hasGroup:
 		// given a group, prefer an exact match.  If you don't find one, resort to a prefix match on group
 		foundExactMatch := false
 		requestedGroupResource := resource.GroupResource()
 		for plural, singular := range m.pluralToSingular {
 			if singular.GroupResource() == requestedGroupResource {
 				foundExactMatch = true
 				ret = append(ret, plural)
 			}
 			if plural.GroupResource() == requestedGroupResource {
 				foundExactMatch = true
 				ret = append(ret, plural)
 			}
 		}

 		// if you didn't find an exact match, match on group prefixing. This allows storageclass.storage to match
 		// storageclass.storage.k8s.io
 		if !foundExactMatch {
 			for plural, singular := range m.pluralToSingular {
 				if !strings.HasPrefix(plural.Group, requestedGroupResource.Group) {
 					continue
 				}
 				if singular.Resource == requestedGroupResource.Resource {
 					ret = append(ret, plural)
 				}
 				if plural.Resource == requestedGroupResource.Resource {
 					ret = append(ret, plural)
 				}
 			}

 		}

 	case hasVersion:
 		for plural, singular := range m.pluralToSingular {
 			if singular.Version == resource.Version && singular.Resource == resource.Resource {
 				ret = append(ret, plural)
 			}
 			if plural.Version == resource.Version && plural.Resource == resource.Resource {
 				ret = append(ret, plural)
 			}
 		}

 	default:
 		for plural, singular := range m.pluralToSingular {
 			if singular.Resource == resource.Resource {
 				ret = append(ret, plural)
 			}
 			if plural.Resource == resource.Resource {
 				ret = append(ret, plural)
 			}
 		}
 	}

 	if len(ret) == 0 {
 		return nil, &NoResourceMatchError{PartialResource: resource}
 	}

 	sort.Sort(resourceByPreferredGroupVersion{ret, m.defaultGroupVersions})
 	return ret, nil
 }

 func (m *DefaultRESTMapper) ResourceFor(resource schema.GroupVersionResource) (schema.GroupVersionResource, error) {
 	resources, err := m.ResourcesFor(resource)
 	if err != nil {
 		return schema.GroupVersionResource{}, err
 	}
 	if len(resources) == 1 {
 		return resources[0], nil
 	}

 	return schema.GroupVersionResource{}, &AmbiguousResourceError{PartialResource: resource, MatchingResources: resources}
 }

 func (m *DefaultRESTMapper) KindsFor(input schema.GroupVersionResource) ([]schema.GroupVersionKind, error) {
 	resource := coerceResourceForMatching(input)

 	hasResource := len(resource.Resource) > 0
 	hasGroup := len(resource.Group) > 0
 	hasVersion := len(resource.Version) > 0

 	if !hasResource {
 		return nil, fmt.Errorf("a resource must be present, got: %v", resource)
 	}

 	ret := []schema.GroupVersionKind{}
 	switch {
 	// fully qualified.  Find the exact match
 	case hasGroup && hasVersion:
 		kind, exists := m.resourceToKind[resource]
 		if exists {
 			ret = append(ret, kind)
 		}

 	case hasGroup:
 		foundExactMatch := false
 		requestedGroupResource := resource.GroupResource()
 		for currResource, currKind := range m.resourceToKind {
 			if currResource.GroupResource() == requestedGroupResource {
 				foundExactMatch = true
 				ret = append(ret, currKind)
 			}
 		}

 		// if you didn't find an exact match, match on group prefixing. This allows storageclass.storage to match
 		// storageclass.storage.k8s.io
 		if !foundExactMatch {
 			for currResource, currKind := range m.resourceToKind {
 				if !strings.HasPrefix(currResource.Group, requestedGroupResource.Group) {
 					continue
 				}
 				if currResource.Resource == requestedGroupResource.Resource {
 					ret = append(ret, currKind)
 				}
 			}

 		}

 	case hasVersion:
 		for currResource, currKind := range m.resourceToKind {
 			if currResource.Version == resource.Version && currResource.Resource == resource.Resource {
 				ret = append(ret, currKind)
 			}
 		}

 	default:
 		for currResource, currKind := range m.resourceToKind {
 			if currResource.Resource == resource.Resource {
 				ret = append(ret, currKind)
 			}
 		}
 	}

 	if len(ret) == 0 {
 		return nil, &NoResourceMatchError{PartialResource: input}
 	}

 	sort.Sort(kindByPreferredGroupVersion{ret, m.defaultGroupVersions})
 	return ret, nil
 }

 func (m *DefaultRESTMapper) KindFor(resource schema.GroupVersionResource) (schema.GroupVersionKind, error) {
 	kinds, err := m.KindsFor(resource)
 	if err != nil {
 		return schema.GroupVersionKind{}, err
 	}
 	if len(kinds) == 1 {
 		return kinds[0], nil
 	}

 	return schema.GroupVersionKind{}, &AmbiguousResourceError{PartialResource: resource, MatchingKinds: kinds}
 }

 type kindByPreferredGroupVersion struct {
 	list      []schema.GroupVersionKind
 	sortOrder []schema.GroupVersion
 }

 func (o kindByPreferredGroupVersion) Len() int      { return len(o.list) }
 func (o kindByPreferredGroupVersion) Swap(i, j int) { o.list[i], o.list[j] = o.list[j], o.list[i] }
 func (o kindByPreferredGroupVersion) Less(i, j int) bool {
 	lhs := o.list[i]
 	rhs := o.list[j]
 	if lhs == rhs {
 		return false
 	}

 	if lhs.GroupVersion() == rhs.GroupVersion() {
 		return lhs.Kind < rhs.Kind
 	}

 	// otherwise, the difference is in the GroupVersion, so we need to sort with respect to the preferred order
 	lhsIndex := -1
 	rhsIndex := -1

 	for i := range o.sortOrder {
 		if o.sortOrder[i] == lhs.GroupVersion() {
 			lhsIndex = i
 		}
 		if o.sortOrder[i] == rhs.GroupVersion() {
 			rhsIndex = i
 		}
 	}

 	if rhsIndex == -1 {
 		return true
 	}

 	return lhsIndex < rhsIndex
 }

 type resourceByPreferredGroupVersion struct {
 	list      []schema.GroupVersionResource
 	sortOrder []schema.GroupVersion
 }

 func (o resourceByPreferredGroupVersion) Len() int      { return len(o.list) }
 func (o resourceByPreferredGroupVersion) Swap(i, j int) { o.list[i], o.list[j] = o.list[j], o.list[i] }
 func (o resourceByPreferredGroupVersion) Less(i, j int) bool {
 	lhs := o.list[i]
 	rhs := o.list[j]
 	if lhs == rhs {
 		return false
 	}

 	if lhs.GroupVersion() == rhs.GroupVersion() {
 		return lhs.Resource < rhs.Resource
 	}

 	// otherwise, the difference is in the GroupVersion, so we need to sort with respect to the preferred order
 	lhsIndex := -1
 	rhsIndex := -1

 	for i := range o.sortOrder {
 		if o.sortOrder[i] == lhs.GroupVersion() {
 			lhsIndex = i
 		}
 		if o.sortOrder[i] == rhs.GroupVersion() {
 			rhsIndex = i
 		}
 	}

 	if rhsIndex == -1 {
 		return true
 	}

 	return lhsIndex < rhsIndex
 }

 // RESTMapping returns a struct representing the resource path and conversion interfaces a
 // RESTClient should use to operate on the provided group/kind in order of versions. If a version search
 // order is not provided, the search order provided to DefaultRESTMapper will be used to resolve which
 // version should be used to access the named group/kind.
 func (m *DefaultRESTMapper) RESTMapping(gk schema.GroupKind, versions ...string) (*RESTMapping, error) {
 	mappings, err := m.RESTMappings(gk, versions...)
 	if err != nil {
 		return nil, err
 	}
 	if len(mappings) == 0 {
 		return nil, &NoKindMatchError{GroupKind: gk, SearchedVersions: versions}
 	}
 	// since we rely on RESTMappings method
 	// take the first match and return to the caller
 	// as this was the existing behavior.
 	return mappings[0], nil
 }

 // RESTMappings returns the RESTMappings for the provided group kind. If a version search order
 // is not provided, the search order provided to DefaultRESTMapper will be used.
 func (m *DefaultRESTMapper) RESTMappings(gk schema.GroupKind, versions ...string) ([]*RESTMapping, error) {
 	mappings := make([]*RESTMapping, 0)
 	potentialGVK := make([]schema.GroupVersionKind, 0)
 	hadVersion := false

 	// Pick an appropriate version
 	for _, version := range versions {
 		if len(version) == 0 || version == runtime.APIVersionInternal {
 			continue
 		}
 		currGVK := gk.WithVersion(version)
 		hadVersion = true
 		if _, ok := m.kindToPluralResource[currGVK]; ok {
 			potentialGVK = append(potentialGVK, currGVK)
 			break
 		}
 	}
 	// Use the default preferred versions
 	if !hadVersion && len(potentialGVK) == 0 {
 		for _, gv := range m.defaultGroupVersions {
 			if gv.Group != gk.Group {
 				continue
 			}
 			potentialGVK = append(potentialGVK, gk.WithVersion(gv.Version))
 		}
 	}

 	if len(potentialGVK) == 0 {
 		return nil, &NoKindMatchError{GroupKind: gk, SearchedVersions: versions}
 	}

 	for _, gvk := range potentialGVK {
 		//Ensure we have a REST mapping
 		res, ok := m.kindToPluralResource[gvk]
 		if !ok {
 			continue
 		}

 		// Ensure we have a REST scope
 		scope, ok := m.kindToScope[gvk]
 		if !ok {
 			return nil, fmt.Errorf("the provided version %q and kind %q cannot be mapped to a supported scope", gvk.GroupVersion(), gvk.Kind)
 		}

 		mappings = append(mappings, &RESTMapping{
 			Resource:         res,
 			GroupVersionKind: gvk,
 			Scope:            scope,
 		})
 	}

 	if len(mappings) == 0 {
 		return nil, &NoResourceMatchError{PartialResource: schema.GroupVersionResource{Group: gk.Group, Resource: gk.Kind}}
 	}
 	return mappings, nil
 }
	/*
	Copyright 2014 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.
	*/

	// TODO: move everything in this file to pkg/api/rest
	package meta

	import (
	"fmt"
	"sort"
	"strings"

	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/schema"
	)

	// Implements RESTScope interface
	type restScope struct {
	name RESTScopeName
	}

	func (r *restScope) Name() RESTScopeName {
	return r.name
	}

	var RESTScopeNamespace = &restScope{
	name: RESTScopeNameNamespace,
	}

	var RESTScopeRoot = &restScope{
	name: RESTScopeNameRoot,
	}

	// DefaultRESTMapper exposes mappings between the types defined in a
	// runtime.Scheme. It assumes that all types defined the provided scheme
	// can be mapped with the provided MetadataAccessor and Codec interfaces.
	//
	// The resource name of a Kind is defined as the lowercase,
	// English-plural version of the Kind string.
	// When converting from resource to Kind, the singular version of the
	// resource name is also accepted for convenience.
	//
	// TODO: Only accept plural for some operations for increased control?
	// (`get pod bar` vs `get pods bar`)
	type DefaultRESTMapper struct {
	defaultGroupVersions []schema.GroupVersion

	resourceToKind map[schema.GroupVersionResource]schema.GroupVersionKind
	kindToPluralResource map[schema.GroupVersionKind]schema.GroupVersionResource
	kindToScope map[schema.GroupVersionKind]RESTScope
	singularToPlural map[schema.GroupVersionResource]schema.GroupVersionResource
	pluralToSingular map[schema.GroupVersionResource]schema.GroupVersionResource
	}

	func (m *DefaultRESTMapper) String() string {
	return fmt.Sprintf("DefaultRESTMapper{kindToPluralResource=%v}", m.kindToPluralResource)
	}

	var _ RESTMapper = &DefaultRESTMapper{}

	// NewDefaultRESTMapper initializes a mapping between Kind and APIVersion
	// to a resource name and back based on the objects in a runtime.Scheme
	// and the Kubernetes API conventions. Takes a group name, a priority list of the versions
	// to search when an object has no default version (set empty to return an error),
	// and a function that retrieves the correct metadata for a given version.
	func NewDefaultRESTMapper(defaultGroupVersions []schema.GroupVersion) *DefaultRESTMapper {
	resourceToKind := make(map[schema.GroupVersionResource]schema.GroupVersionKind)
	kindToPluralResource := make(map[schema.GroupVersionKind]schema.GroupVersionResource)
	kindToScope := make(map[schema.GroupVersionKind]RESTScope)
	singularToPlural := make(map[schema.GroupVersionResource]schema.GroupVersionResource)
	pluralToSingular := make(map[schema.GroupVersionResource]schema.GroupVersionResource)
	// TODO: verify name mappings work correctly when versions differ

	return &DefaultRESTMapper{
	resourceToKind: resourceToKind,
	kindToPluralResource: kindToPluralResource,
	kindToScope: kindToScope,
	defaultGroupVersions: defaultGroupVersions,
	singularToPlural: singularToPlural,
	pluralToSingular: pluralToSingular,
	}
	}

	func (m *DefaultRESTMapper) Add(kind schema.GroupVersionKind, scope RESTScope) {
	plural, singular := UnsafeGuessKindToResource(kind)
	m.AddSpecific(kind, plural, singular, scope)
	}

	func (m *DefaultRESTMapper) AddSpecific(kind schema.GroupVersionKind, plural, singular schema.GroupVersionResource, scope RESTScope) {
	m.singularToPlural[singular] = plural
	m.pluralToSingular[plural] = singular

	m.resourceToKind[singular] = kind
	m.resourceToKind[plural] = kind

	m.kindToPluralResource[kind] = plural
	m.kindToScope[kind] = scope
	}

	// unpluralizedSuffixes is a list of resource suffixes that are the same plural and singular
	// This is only is only necessary because some bits of code are lazy and don't actually use the RESTMapper like they should.
	// TODO eliminate this so that different callers can correctly map to resources. This probably means updating all
	// callers to use the RESTMapper they mean.
	var unpluralizedSuffixes = []string{
	"endpoints",
	}

	// UnsafeGuessKindToResource converts Kind to a resource name.
	// Broken. This method only "sort of" works when used outside of this package. It assumes that Kinds and Resources match
	// and they aren't guaranteed to do so.
	func UnsafeGuessKindToResource(kind schema.GroupVersionKind) ( /plural/ schema.GroupVersionResource /singular/, schema.GroupVersionResource) {
	kindName := kind.Kind
	if len(kindName) == 0 {
	return schema.GroupVersionResource{}, schema.GroupVersionResource{}
	}
	singularName := strings.ToLower(kindName)
	singular := kind.GroupVersion().WithResource(singularName)

	for _, skip := range unpluralizedSuffixes {
	if strings.HasSuffix(singularName, skip) {
	return singular, singular
	}
	}

	switch string(singularName[len(singularName)-1]) {
	case "s":
	return kind.GroupVersion().WithResource(singularName + "es"), singular
	case "y":
	return kind.GroupVersion().WithResource(strings.TrimSuffix(singularName, "y") + "ies"), singular
	}

	return kind.GroupVersion().WithResource(singularName + "s"), singular
	}

	// ResourceSingularizer implements RESTMapper
	// It converts a resource name from plural to singular (e.g., from pods to pod)
	func (m *DefaultRESTMapper) ResourceSingularizer(resourceType string) (string, error) {
	partialResource := schema.GroupVersionResource{Resource: resourceType}
	resources, err := m.ResourcesFor(partialResource)
	if err != nil {
	return resourceType, err
	}

	singular := schema.GroupVersionResource{}
	for _, curr := range resources {
	currSingular, ok := m.pluralToSingular[curr]
	if !ok {
	continue
	}
	if singular.Empty() {
	singular = currSingular
	continue
	}

	if currSingular.Resource != singular.Resource {
	return resourceType, fmt.Errorf("multiple possible singular resources (%v) found for %v", resources, resourceType)
	}
	}

	if singular.Empty() {
	return resourceType, fmt.Errorf("no singular of resource %v has been defined", resourceType)
	}

	return singular.Resource, nil
	}

	// coerceResourceForMatching makes the resource lower case and converts internal versions to unspecified (legacy behavior)
	func coerceResourceForMatching(resource schema.GroupVersionResource) schema.GroupVersionResource {
	resource.Resource = strings.ToLower(resource.Resource)
	if resource.Version == runtime.APIVersionInternal {
	resource.Version = ""
	}

	return resource
	}

	func (m *DefaultRESTMapper) ResourcesFor(input schema.GroupVersionResource) ([]schema.GroupVersionResource, error) {
	resource := coerceResourceForMatching(input)

	hasResource := len(resource.Resource) > 0
	hasGroup := len(resource.Group) > 0
	hasVersion := len(resource.Version) > 0

	if !hasResource {
	return nil, fmt.Errorf("a resource must be present, got: %v", resource)
	}

	ret := []schema.GroupVersionResource{}
	switch {
	case hasGroup && hasVersion:
	// fully qualified. Find the exact match
	for plural, singular := range m.pluralToSingular {
	if singular == resource {
	ret = append(ret, plural)
	break
	}
	if plural == resource {
	ret = append(ret, plural)
	break
	}
	}

	case hasGroup:
	// given a group, prefer an exact match. If you don't find one, resort to a prefix match on group
	foundExactMatch := false
	requestedGroupResource := resource.GroupResource()
	for plural, singular := range m.pluralToSingular {
	if singular.GroupResource() == requestedGroupResource {
	foundExactMatch = true
	ret = append(ret, plural)
	}
	if plural.GroupResource() == requestedGroupResource {
	foundExactMatch = true
	ret = append(ret, plural)
	}
	}

	// if you didn't find an exact match, match on group prefixing. This allows storageclass.storage to match
	// storageclass.storage.k8s.io
	if !foundExactMatch {
	for plural, singular := range m.pluralToSingular {
	if !strings.HasPrefix(plural.Group, requestedGroupResource.Group) {
	continue
	}
	if singular.Resource == requestedGroupResource.Resource {
	ret = append(ret, plural)
	}
	if plural.Resource == requestedGroupResource.Resource {
	ret = append(ret, plural)
	}
	}

	}

	case hasVersion:
	for plural, singular := range m.pluralToSingular {
	if singular.Version == resource.Version && singular.Resource == resource.Resource {
	ret = append(ret, plural)
	}
	if plural.Version == resource.Version && plural.Resource == resource.Resource {
	ret = append(ret, plural)
	}
	}

	default:
	for plural, singular := range m.pluralToSingular {
	if singular.Resource == resource.Resource {
	ret = append(ret, plural)
	}
	if plural.Resource == resource.Resource {
	ret = append(ret, plural)
	}
	}
	}

	if len(ret) == 0 {
	return nil, &NoResourceMatchError{PartialResource: resource}
	}

	sort.Sort(resourceByPreferredGroupVersion{ret, m.defaultGroupVersions})
	return ret, nil
	}

	func (m *DefaultRESTMapper) ResourceFor(resource schema.GroupVersionResource) (schema.GroupVersionResource, error) {
	resources, err := m.ResourcesFor(resource)
	if err != nil {
	return schema.GroupVersionResource{}, err
	}
	if len(resources) == 1 {
	return resources[0], nil
	}

	return schema.GroupVersionResource{}, &AmbiguousResourceError{PartialResource: resource, MatchingResources: resources}
	}

	func (m *DefaultRESTMapper) KindsFor(input schema.GroupVersionResource) ([]schema.GroupVersionKind, error) {
	resource := coerceResourceForMatching(input)

	hasResource := len(resource.Resource) > 0
	hasGroup := len(resource.Group) > 0
	hasVersion := len(resource.Version) > 0

	if !hasResource {
	return nil, fmt.Errorf("a resource must be present, got: %v", resource)
	}

	ret := []schema.GroupVersionKind{}
	switch {
	// fully qualified. Find the exact match
	case hasGroup && hasVersion:
	kind, exists := m.resourceToKind[resource]
	if exists {
	ret = append(ret, kind)
	}

	case hasGroup:
	foundExactMatch := false
	requestedGroupResource := resource.GroupResource()
	for currResource, currKind := range m.resourceToKind {
	if currResource.GroupResource() == requestedGroupResource {
	foundExactMatch = true
	ret = append(ret, currKind)
	}
	}

	// if you didn't find an exact match, match on group prefixing. This allows storageclass.storage to match
	// storageclass.storage.k8s.io
	if !foundExactMatch {
	for currResource, currKind := range m.resourceToKind {
	if !strings.HasPrefix(currResource.Group, requestedGroupResource.Group) {
	continue
	}
	if currResource.Resource == requestedGroupResource.Resource {
	ret = append(ret, currKind)
	}
	}

	}

	case hasVersion:
	for currResource, currKind := range m.resourceToKind {
	if currResource.Version == resource.Version && currResource.Resource == resource.Resource {
	ret = append(ret, currKind)
	}
	}

	default:
	for currResource, currKind := range m.resourceToKind {
	if currResource.Resource == resource.Resource {
	ret = append(ret, currKind)
	}
	}
	}

	if len(ret) == 0 {
	return nil, &NoResourceMatchError{PartialResource: input}
	}

	sort.Sort(kindByPreferredGroupVersion{ret, m.defaultGroupVersions})
	return ret, nil
	}

	func (m *DefaultRESTMapper) KindFor(resource schema.GroupVersionResource) (schema.GroupVersionKind, error) {
	kinds, err := m.KindsFor(resource)
	if err != nil {
	return schema.GroupVersionKind{}, err
	}
	if len(kinds) == 1 {
	return kinds[0], nil
	}

	return schema.GroupVersionKind{}, &AmbiguousResourceError{PartialResource: resource, MatchingKinds: kinds}
	}

	type kindByPreferredGroupVersion struct {
	list []schema.GroupVersionKind
	sortOrder []schema.GroupVersion
	}

	func (o kindByPreferredGroupVersion) Len() int { return len(o.list) }
	func (o kindByPreferredGroupVersion) Swap(i, j int) { o.list[i], o.list[j] = o.list[j], o.list[i] }
	func (o kindByPreferredGroupVersion) Less(i, j int) bool {
	lhs := o.list[i]
	rhs := o.list[j]
	if lhs == rhs {
	return false
	}

	if lhs.GroupVersion() == rhs.GroupVersion() {
	return lhs.Kind < rhs.Kind
	}

	// otherwise, the difference is in the GroupVersion, so we need to sort with respect to the preferred order
	lhsIndex := -1
	rhsIndex := -1

	for i := range o.sortOrder {
	if o.sortOrder[i] == lhs.GroupVersion() {
	lhsIndex = i
	}
	if o.sortOrder[i] == rhs.GroupVersion() {
	rhsIndex = i
	}
	}

	if rhsIndex == -1 {
	return true
	}

	return lhsIndex < rhsIndex
	}

	type resourceByPreferredGroupVersion struct {
	list []schema.GroupVersionResource
	sortOrder []schema.GroupVersion
	}

	func (o resourceByPreferredGroupVersion) Len() int { return len(o.list) }
	func (o resourceByPreferredGroupVersion) Swap(i, j int) { o.list[i], o.list[j] = o.list[j], o.list[i] }
	func (o resourceByPreferredGroupVersion) Less(i, j int) bool {
	lhs := o.list[i]
	rhs := o.list[j]
	if lhs == rhs {
	return false
	}

	if lhs.GroupVersion() == rhs.GroupVersion() {
	return lhs.Resource < rhs.Resource
	}

	// otherwise, the difference is in the GroupVersion, so we need to sort with respect to the preferred order
	lhsIndex := -1
	rhsIndex := -1

	for i := range o.sortOrder {
	if o.sortOrder[i] == lhs.GroupVersion() {
	lhsIndex = i
	}
	if o.sortOrder[i] == rhs.GroupVersion() {
	rhsIndex = i
	}
	}

	if rhsIndex == -1 {
	return true
	}

	return lhsIndex < rhsIndex
	}

	// RESTMapping returns a struct representing the resource path and conversion interfaces a
	// RESTClient should use to operate on the provided group/kind in order of versions. If a version search
	// order is not provided, the search order provided to DefaultRESTMapper will be used to resolve which
	// version should be used to access the named group/kind.
	func (m DefaultRESTMapper) RESTMapping(gk schema.GroupKind, versions ...string) (RESTMapping, error) {
	mappings, err := m.RESTMappings(gk, versions...)
	if err != nil {
	return nil, err
	}
	if len(mappings) == 0 {
	return nil, &NoKindMatchError{GroupKind: gk, SearchedVersions: versions}
	}
	// since we rely on RESTMappings method
	// take the first match and return to the caller
	// as this was the existing behavior.
	return mappings[0], nil
	}

	// RESTMappings returns the RESTMappings for the provided group kind. If a version search order
	// is not provided, the search order provided to DefaultRESTMapper will be used.
	func (m DefaultRESTMapper) RESTMappings(gk schema.GroupKind, versions ...string) ([]RESTMapping, error) {
	mappings := make([]*RESTMapping, 0)
	potentialGVK := make([]schema.GroupVersionKind, 0)
	hadVersion := false

	// Pick an appropriate version
	for _, version := range versions {
	if len(version) == 0 \|\| version == runtime.APIVersionInternal {
	continue
	}
	currGVK := gk.WithVersion(version)
	hadVersion = true
	if _, ok := m.kindToPluralResource[currGVK]; ok {
	potentialGVK = append(potentialGVK, currGVK)
	break
	}
	}
	// Use the default preferred versions
	if !hadVersion && len(potentialGVK) == 0 {
	for _, gv := range m.defaultGroupVersions {
	if gv.Group != gk.Group {
	continue
	}
	potentialGVK = append(potentialGVK, gk.WithVersion(gv.Version))
	}
	}

	if len(potentialGVK) == 0 {
	return nil, &NoKindMatchError{GroupKind: gk, SearchedVersions: versions}
	}

	for _, gvk := range potentialGVK {
	//Ensure we have a REST mapping
	res, ok := m.kindToPluralResource[gvk]
	if !ok {
	continue
	}

	// Ensure we have a REST scope
	scope, ok := m.kindToScope[gvk]
	if !ok {
	return nil, fmt.Errorf("the provided version %q and kind %q cannot be mapped to a supported scope", gvk.GroupVersion(), gvk.Kind)
	}

	mappings = append(mappings, &RESTMapping{
	Resource: res,
	GroupVersionKind: gvk,
	Scope: scope,
	})
	}

	if len(mappings) == 0 {
	return nil, &NoResourceMatchError{PartialResource: schema.GroupVersionResource{Group: gk.Group, Resource: gk.Kind}}
	}
	return mappings, nil
	}