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vendor/k8s.io/apimachinery/pkg/api/safe/safe.go

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+/*
+Copyright 2024 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 safe
+
+// Field takes a pointer to any value (which may or may not be nil) and a
+// function that traverses to a target type R (a typical use case is to
+// dereference a field), and returns the result of the traversal, or the zero
+// value of the target type.
+//
+// This is roughly equivalent to:
+//
+//	value != nil ? fn(value) : zero-value
+//
+// ...in languages that support the ternary operator.
+func Field[V any, R any](value *V, fn func(*V) R) R {
+	if value == nil {
+		var zero R
+		return zero
+	}
+	o := fn(value)
+	return o
+}
+
+// Cast takes any value, attempts to cast it to T, and returns the T value if
+// the cast is successful, or else the zero value of T.
+func Cast[T any](value any) T {
+	result, _ := value.(T)
+	return result
+}
+
+// Value takes a pointer to any value (which may or may not be nil) and a
+// function that returns a pointer to the same type.  If the value is not nil,
+// it is returned, otherwise the result of the function is returned.
+//
+// This is roughly equivalent to:
+//
+//	value != nil ? value : fn()
+//
+// ...in languages that support the ternary operator.
+func Value[T any](value *T, fn func() *T) *T {
+	if value != nil {
+		return value
+	}
+	return fn()
+}