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.
• Types which implement interface { AppendTo([]byte) []byte } use the AppendTo method to produce a textual representation of the value. Thus, two values are equal if AppendTo produces the same bytes.

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(last *Sum, v ...any) (changed bool)
• type Sum
  • func Hash(v any) (s Sum)
  • func (s Sum) String() string

Functions

func HasherForType

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

HasherForType is like Hash, but it returns a Hash func that's specialized for the provided reflect type, avoiding a map lookup per value.

func Update

func Update(last *Sum, v ...any) (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(v any) (s Sum)

Hash returns the hash of v.

func (Sum) String

func (s Sum) String() string