text: /*
  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.
  */
  
  package meta
  
  import (
  	"fmt"
  
  	"k8s.io/apimachinery/pkg/runtime/schema"
  	utilerrors "k8s.io/apimachinery/pkg/util/errors"
  )
  
  // FirstHitRESTMapper is a wrapper for multiple RESTMappers which returns the
  // first successful result for the singular requests
  type FirstHitRESTMapper struct {
  	MultiRESTMapper
  }
  
  func (m FirstHitRESTMapper) String() string {
  	return fmt.Sprintf("FirstHitRESTMapper{\n\t%v\n}", m.MultiRESTMapper)
  }
  
  func (m FirstHitRESTMapper) ResourceFor(resource schema.GroupVersionResource) (schema.GroupVersionResource, error) {
  	errors := []error{}
  	for _, t := range m.MultiRESTMapper {
  		ret, err := t.ResourceFor(resource)
  		if err == nil {
  			return ret, nil
  		}
  		errors = append(errors, err)
  	}
  
  	return schema.GroupVersionResource{}, collapseAggregateErrors(errors)
  }
  
  func (m FirstHitRESTMapper) KindFor(resource schema.GroupVersionResource) (schema.GroupVersionKind, error) {
  	errors := []error{}
  	for _, t := range m.MultiRESTMapper {
  		ret, err := t.KindFor(resource)
  		if err == nil {
  			return ret, nil
  		}
  		errors = append(errors, err)
  	}
  
  	return schema.GroupVersionKind{}, collapseAggregateErrors(errors)
  }
  
  // RESTMapping provides the REST mapping for the resource based on the
  // kind and version. This implementation supports multiple REST schemas and
  // return the first match.
  func (m FirstHitRESTMapper) RESTMapping(gk schema.GroupKind, versions ...string) (*RESTMapping, error) {
  	errors := []error{}
  	for _, t := range m.MultiRESTMapper {
  		ret, err := t.RESTMapping(gk, versions...)
  		if err == nil {
  			return ret, nil
  		}
  		errors = append(errors, err)
  	}
  
  	return nil, collapseAggregateErrors(errors)
  }
  
  // collapseAggregateErrors returns the minimal errors.  it handles empty as nil, handles one item in a list
  // by returning the item, and collapses all NoMatchErrors to a single one (since they should all be the same)
  func collapseAggregateErrors(errors []error) error {
  	if len(errors) == 0 {
  		return nil
  	}
  	if len(errors) == 1 {
  		return errors[0]
  	}
  
  	allNoMatchErrors := true
  	for _, err := range errors {
  		allNoMatchErrors = allNoMatchErrors && IsNoMatchError(err)
  	}
  	if allNoMatchErrors {
  		return errors[0]
  	}
  
  	return utilerrors.NewAggregate(errors)
  }
  