Move Resource functionality to its own package

Create a unified Builder object for working with files, selectors,
types, and items that makes it easier to get multi-object functionality.

Supports all of the behaviors previously in resource.go, but with
additional flexibility to allow multi-type retrieval and access, directories,
URLs, nested objects, and lists.

pkg/kubectl/resource/selector.go

@@ -0,0 +1,80 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+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 resource
+
+import (
+	"github.com/golang/glog"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/meta"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
+)
+
+// Selector is a Visitor for resources that match a label selector.
+type Selector struct {
+	Client    RESTClient
+	Mapping   *meta.RESTMapping
+	Namespace string
+	Selector  labels.Selector
+}
+
+// NewSelector creates a resource selector which hides details of getting items by their label selector.
+func NewSelector(client RESTClient, mapping *meta.RESTMapping, namespace string, selector labels.Selector) *Selector {
+	return &Selector{
+		Client:    client,
+		Mapping:   mapping,
+		Namespace: namespace,
+		Selector:  selector,
+	}
+}
+
+// Visit implements Visitor
+func (r *Selector) Visit(fn VisitorFunc) error {
+	list, err := NewHelper(r.Client, r.Mapping).List(r.Namespace, r.Selector)
+	if err != nil {
+		if errors.IsBadRequest(err) || errors.IsNotFound(err) {
+			if r.Selector.Empty() {
+				glog.V(2).Infof("Unable to list %q: %v", r.Mapping.Resource, err)
+			} else {
+				glog.V(2).Infof("Unable to find %q that match the selector %q: %v", r.Mapping.Resource, r.Selector, err)
+			}
+			return nil
+		}
+		return err
+	}
+	accessor := r.Mapping.MetadataAccessor
+	resourceVersion, _ := accessor.ResourceVersion(list)
+	info := &Info{
+		Client:    r.Client,
+		Mapping:   r.Mapping,
+		Namespace: r.Namespace,
+
+		Object:          list,
+		ResourceVersion: resourceVersion,
+	}
+	return fn(info)
+}
+
+func (r *Selector) Watch(resourceVersion string) (watch.Interface, error) {
+	return NewHelper(r.Client, r.Mapping).Watch(r.Namespace, resourceVersion, r.Selector, labels.Everything())
+}
+
+// ResourceMapping returns the mapping for this resource and implements ResourceMapping
+func (r *Selector) ResourceMapping() *meta.RESTMapping {
+	return r.Mapping
+}