deephash

Documentation

Overview

Package deephash hashes a Go value recursively, in a predictable order, without looping. The hash is only valid within the lifetime of a program. Users should not store the hash on disk or send it over the network. The hash is sufficiently strong and unique such that Hash(&x) == Hash(&y) is an appropriate replacement for x == y.

The definition of equality is identical to reflect.DeepEqual except:

• Floating-point values are compared based on the raw bits, which means that NaNs (with the same bit pattern) are treated as equal.
• time.Time are compared based on whether they are the same instant in time and also in the same zone offset. Monotonic measurements and zone names are ignored as part of the hash.
• netip.Addr are compared based on a shallow comparison of the struct.

WARNING: This package, like most of the tailscale.com Go module, should be considered Tailscale-internal; we make no API promises.

Index

• func HasherForType[T any]() func(*T) Sum
• func Update[T any](last *Sum, v *T) (changed bool)
• type Sum
  • func Hash[T any](v *T) Sum
  • func (s Sum) AppendTo(b []byte) []byte
  • func (s Sum) String() string

Functions

func HasherForType

func HasherForType[T any]() func(*T) Sum

HasherForType returns a hash that is specialized for the provided type.

func Update

func Update[T any](last *Sum, v *T) (changed bool)

Update sets last to the hash of v and reports whether its value changed.

Types

type Sum

type Sum struct {
	// contains filtered or unexported fields
}

Sum is an opaque checksum type that is comparable.

func Hash

func Hash[T any](v *T) Sum

Hash returns the hash of v.

func (Sum) AppendTo

func (s Sum) AppendTo(b []byte) []byte

AppendTo appends the string encoding of this sum (as returned by the String method) to the provided byte slice and returns the extended buffer.

func (Sum) String

func (s Sum) String() string