Optimize NegotiateMediaTypeOptions

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/negotiation/negotiate.go

@@ -234,13 +234,6 @@ func acceptMediaTypeOptions(params map[string]string, accepts *runtime.Serialize
 	return options, true
 }
 
-type candidateMediaType struct {
-	accepted *runtime.SerializerInfo
-	clauses  goautoneg.Accept
-}
-
-type candidateMediaTypeSlice []candidateMediaType
-
 // NegotiateMediaTypeOptions returns the most appropriate content type given the accept header and
 // a list of alternatives along with the accepted media type parameters.
 func NegotiateMediaTypeOptions(header string, accepted []runtime.SerializerInfo, endpoint EndpointRestrictions) (MediaTypeOptions, bool) {
@@ -250,25 +243,21 @@ func NegotiateMediaTypeOptions(header string, accepted []runtime.SerializerInfo,
 		}, true
 	}
 
-	var candidates candidateMediaTypeSlice
 	clauses := goautoneg.ParseAccept(header)
-	for _, clause := range clauses {
+	for i := range clauses {
+		clause := &clauses[i]
 		for i := range accepted {
 			accepts := &accepted[i]
 			switch {
 			case clause.Type == accepts.MediaTypeType && clause.SubType == accepts.MediaTypeSubType,
 				clause.Type == accepts.MediaTypeType && clause.SubType == "*",
 				clause.Type == "*" && clause.SubType == "*":
-				candidates = append(candidates, candidateMediaType{accepted: accepts, clauses: clause})
+				if retVal, ret := acceptMediaTypeOptions(clause.Params, accepts, endpoint); ret {
+					return retVal, true
+				}
 			}
 		}
 	}
 
-	for _, v := range candidates {
-		if retVal, ret := acceptMediaTypeOptions(v.clauses.Params, v.accepted, endpoint); ret {
-			return retVal, true
-		}
-	}
-
 	return MediaTypeOptions{}, false
 }

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/negotiation/negotiate_test.go

@@ -280,3 +280,30 @@ func TestNegotiate(t *testing.T) {
 		}
 	}
 }
+
+func fakeSerializerInfoSlice() []runtime.SerializerInfo {
+	result := make([]runtime.SerializerInfo, 2)
+	result[0] = runtime.SerializerInfo{
+		MediaType:        "application/json",
+		MediaTypeType:    "application",
+		MediaTypeSubType: "json",
+	}
+	result[1] = runtime.SerializerInfo{
+		MediaType:        "application/vnd.kubernetes.protobuf",
+		MediaTypeType:    "application",
+		MediaTypeSubType: "vnd.kubernetes.protobuf",
+	}
+	return result
+}
+
+func BenchmarkNegotiateMediaTypeOptions(b *testing.B) {
+	accepted := fakeSerializerInfoSlice()
+	header := "application/vnd.kubernetes.protobuf,*/*"
+
+	for i := 0; i < b.N; i++ {
+		options, _ := NegotiateMediaTypeOptions(header, accepted, DefaultEndpointRestrictions)
+		if options.Accepted != accepted[1] {
+			b.Errorf("Unexpected result")
+		}
+	}
+}