tailcfg: use cmd/viewer instead of cmd/cloner.

Signed-off-by: Maisem Ali <maisem@tailscale.com>

types/dnstype/dnstype_view.go

@@ -0,0 +1,69 @@
+// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code generated by tailscale.com/util/codegen (viewer); DO NOT EDIT.
+
+package dnstype
+
+import (
+	"encoding/json"
+	"errors"
+
+	"inet.af/netaddr"
+	"tailscale.com/types/views"
+)
+
+//go:generate go run tailscale.com/cmd/cloner  -clonefunc=true -type=Resolver
+// View returns a readonly view of Resolver.
+func (p *Resolver) View() ResolverView {
+	return ResolverView{ж: p}
+}
+
+// ResolverView provides a read-only view on Resolver.
+// It's methods should only be called if `Valid()` returns true.
+type ResolverView struct {
+	// It is named distinctively to make you think of how dangerous it is to escape
+	// to callers. You must not let callers be able to mutate it.
+	ж *Resolver
+}
+
+// Valid reports whether underlying value is non-nil.
+func (v ResolverView) Valid() bool { return v.ж != nil }
+
+// AsStruct returns a clone of the underlying value which aliases no memory with
+// the original.
+func (v ResolverView) AsStruct() *Resolver {
+	if v.ж != nil {
+		return nil
+	}
+	return v.ж.Clone()
+}
+
+func (v ResolverView) MarshalJSON() ([]byte, error) { return json.Marshal(v.ж) }
+
+func (v *ResolverView) UnmarshalJSON(b []byte) error {
+	if v.ж != nil {
+		return errors.New("already initialized")
+	}
+	if len(b) == 0 {
+		return nil
+	}
+	var x Resolver
+	if err := json.Unmarshal(b, &x); err != nil {
+		return err
+	}
+	v.ж = &x
+	return nil
+}
+
+func (v ResolverView) Addr() string { return v.ж.Addr }
+func (v ResolverView) BootstrapResolution() views.Slice[netaddr.IP] {
+	return views.SliceOf(v.ж.BootstrapResolution)
+}
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+var _ResolverViewNeedsRegeneration = Resolver(struct {
+	Addr                string
+	BootstrapResolution []netaddr.IP
+}{})