tailscale/util/checkchange/checkchange.go
Brad Fitzpatrick f270c3158a net/dns, ipn/ipnlocal: fix regressions from change moving away from deephash
I got sidetracked apparently and never finished writing this Clone
code in 316afe7d02babc (#17448). (It really should use views instead.)

And then I missed one of the users of "routerChanged" that was broken up
into "routerChanged" vs "dnsChanged".

This broke integration tests elsewhere.

Fixes #17506

Change-Id: I533bf0fcf3da9ac6eb4a6cdef03b8df2c1fb4c8e
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
2025-10-08 17:58:32 -07:00

26 lines
704 B
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// Package checkchange defines a utility for determining whether a value
// has changed since the last time it was checked.
package checkchange
// EqualCloner is an interface for types that can be compared for equality
// and can be cloned.
type EqualCloner[T any] interface {
Equal(T) bool
Clone() T
}
// Update sets *old to a clone of new if they are not equal, returning whether
// they were different.
//
// It only modifies *old if they are different. old must be non-nil.
func Update[T EqualCloner[T]](old *T, new T) (changed bool) {
if (*old).Equal(new) {
return false
}
*old = new.Clone()
return true
}