optimize code

staging/src/k8s.io/apiserver/pkg/storage/selection_predicate.go

@@ -17,9 +17,8 @@ limitations under the License.
 package storage
 
 import (
-	"strings"
+	"context"
 
-	"golang.org/x/net/context"
 	"k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apimachinery/pkg/fields"
 	"k8s.io/apimachinery/pkg/labels"
@@ -150,45 +149,15 @@ func (s *SelectionPredicate) Empty() bool {
 // of objects that return <value> for a given index, a pair (<index name>, <value>)
 // wil be returned.
 func (s *SelectionPredicate) MatcherIndex(ctx context.Context) []MatchValue {
-	re, _ := request.RequestInfoFrom(ctx)
-	if re == nil || !re.IsResourceRequest || re.Subresource != "" || !whitelistResource(re.Resource) {
-		return s.matcherIndex(nil)
-	}
-
-	var metaNamespaceSelector fields.Selector
-	// case1: list with namespace in url. i.e. /api/v1/namespaces/default/pods or /api/v1/namespaces/default/pods?fieldSelector=metadata.namespace=kube-system
-	if re.Namespace != "" {
-		if value, found := s.Field.RequiresExactMatch("metadata.namespace"); !found || value != re.Namespace {
-			metaNamespaceSelector = fields.OneTermEqualSelector("metadata.namespace", re.Namespace)
-		}
-	}
-	// case2: list all pods with namespace in query params. i.e. /api/v1/pods?fieldSelector=metadata.namespace=default
-	return s.matcherIndex(metaNamespaceSelector)
-}
-
-// whitelistResource only allows pod to pass that represents only listing pods will enable namespace indexer
-func whitelistResource(resource string) bool {
-	return strings.EqualFold(resource, "pods")
-}
-
-func (s *SelectionPredicate) matcherIndex(metaNamespaceSelector fields.Selector) []MatchValue {
 	var result []MatchValue
 	for _, field := range s.IndexFields {
-		var (
-			val   string
-			found bool
-		)
-		if metaNamespaceSelector != nil {
-			val, found = metaNamespaceSelector.RequiresExactMatch(field)
-			// skip if found metadata.namespace
-			if found {
-				result = append(result, MatchValue{IndexName: FieldIndex(field), Value: val})
-				continue
-			}
-		}
-
 		if value, ok := s.Field.RequiresExactMatch(field); ok {
 			result = append(result, MatchValue{IndexName: FieldIndex(field), Value: value})
+		} else if field == "metadata.namespace" {
+			// list pods in the namespace. i.e. /api/v1/namespaces/default/pods
+			if namespace, isNamespaceScope := isNamespaceScopedRequest(ctx); isNamespaceScope {
+				result = append(result, MatchValue{IndexName: FieldIndex(field), Value: namespace})
+			}
 		}
 	}
 	for _, label := range s.IndexLabels {
@@ -199,6 +168,14 @@ func (s *SelectionPredicate) matcherIndex(metaNamespaceSelector fields.Selector)
 	return result
 }
 
+func isNamespaceScopedRequest(ctx context.Context) (string, bool) {
+	re, _ := request.RequestInfoFrom(ctx)
+	if re == nil {
+		return "", false
+	}
+	return re.Namespace, re.Namespace != ""
+}
+
 // LabelIndex add prefix for label index.
 func LabelIndex(label string) string {
 	return "l:" + label