ipn/prefs: add views

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

types/persist/persist.go

@@ -12,7 +12,7 @@ import (
 	"tailscale.com/types/structs"
 )
 
-//go:generate go run tailscale.com/cmd/cloner -type=Persist
+//go:generate go run tailscale.com/cmd/viewer -type=Persist
 
 // Persist is the JSON type stored on disk on nodes to remember their
 // settings between runs.

types/persist/persist_view.go

@@ -0,0 +1,80 @@
+// 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/cmd/viewer; DO NOT EDIT.
+
+package persist
+
+import (
+	"encoding/json"
+	"errors"
+
+	"tailscale.com/types/key"
+	"tailscale.com/types/structs"
+)
+
+//go:generate go run tailscale.com/cmd/cloner  -clonefunc=false -type=Persist
+
+// View returns a readonly view of Persist.
+func (p *Persist) View() PersistView {
+	return PersistView{ж: p}
+}
+
+// PersistView provides a read-only view over Persist.
+//
+// Its methods should only be called if `Valid()` returns true.
+type PersistView struct {
+	// ж is the underlying mutable value, named with a hard-to-type
+	// character that looks pointy like a pointer.
+	// 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 *Persist
+}
+
+// Valid reports whether underlying value is non-nil.
+func (v PersistView) Valid() bool { return v.ж != nil }
+
+// AsStruct returns a clone of the underlying value which aliases no memory with
+// the original.
+func (v PersistView) AsStruct() *Persist {
+	if v.ж == nil {
+		return nil
+	}
+	return v.ж.Clone()
+}
+
+func (v PersistView) MarshalJSON() ([]byte, error) { return json.Marshal(v.ж) }
+
+func (v *PersistView) UnmarshalJSON(b []byte) error {
+	if v.ж != nil {
+		return errors.New("already initialized")
+	}
+	if len(b) == 0 {
+		return nil
+	}
+	var x Persist
+	if err := json.Unmarshal(b, &x); err != nil {
+		return err
+	}
+	v.ж = &x
+	return nil
+}
+
+func (v PersistView) LegacyFrontendPrivateMachineKey() key.MachinePrivate {
+	return v.ж.LegacyFrontendPrivateMachineKey
+}
+func (v PersistView) PrivateNodeKey() key.NodePrivate    { return v.ж.PrivateNodeKey }
+func (v PersistView) OldPrivateNodeKey() key.NodePrivate { return v.ж.OldPrivateNodeKey }
+func (v PersistView) Provider() string                   { return v.ж.Provider }
+func (v PersistView) LoginName() string                  { return v.ж.LoginName }
+
+// A compilation failure here means this code must be regenerated, with the command at the top of this file.
+var _PersistViewNeedsRegeneration = Persist(struct {
+	_                               structs.Incomparable
+	LegacyFrontendPrivateMachineKey key.MachinePrivate
+	PrivateNodeKey                  key.NodePrivate
+	OldPrivateNodeKey               key.NodePrivate
+	Provider                        string
+	LoginName                       string
+}{})

types/views/views.go

@@ -201,6 +201,11 @@ func (v IPPrefixSlice) AsSlice() []netip.Prefix {
 	return v.ж.AsSlice()
 }
 
+// Filter returns a new slice, containing elements of v that match f.
+func (v IPPrefixSlice) Filter(f func(netip.Prefix) bool) []netip.Prefix {
+	return tsaddr.FilterPrefixesCopy(v.ж.ж, f)
+}
+
 // PrefixesContainsIP reports whether any IPPrefix contains IP.
 func (v IPPrefixSlice) ContainsIP(ip netip.Addr) bool {
 	return tsaddr.PrefixesContainsIP(v.ж.ж, ip)