build source

vendor/k8s.io/apimachinery/pkg/api/validate/subfield.go

@@ -0,0 +1,53 @@
+/*
+Copyright 2025 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 validate
+
+import (
+	"context"
+
+	"k8s.io/apimachinery/pkg/api/operation"
+	"k8s.io/apimachinery/pkg/util/validation/field"
+)
+
+// GetFieldFunc is a function that extracts a field from a type and returns a
+// nilable value.
+type GetFieldFunc[Tstruct any, Tfield any] func(*Tstruct) Tfield
+
+// Subfield validates a subfield of a struct against a validator function. If
+// the value of the subfield is the same as the previous value, as per the
+// equiv function, then no validation is performed.
+//
+// The fldPath passed to the validator includes the subfield name.
+func Subfield[Tstruct any, Tfield any](
+	ctx context.Context, op operation.Operation, fldPath *field.Path,
+	newStruct, oldStruct *Tstruct,
+	fldName string, getField GetFieldFunc[Tstruct, Tfield],
+	equiv MatchFunc[Tfield],
+	validator ValidateFunc[Tfield],
+) field.ErrorList {
+	var errs field.ErrorList
+	newVal := getField(newStruct)
+	var oldVal Tfield
+	if oldStruct != nil {
+		oldVal = getField(oldStruct)
+	}
+	if op.Type == operation.Update && oldStruct != nil && equiv(newVal, oldVal) {
+		return nil
+	}
+	errs = append(errs, validator(ctx, op, fldPath.Child(fldName), newVal, oldVal)...)
+	return errs
+}