ledger

Documentation

Overview

Package ledger implements a modified map with three unique characteristics: 1. every unique state of the map is given a unique hash 2. prior states of the map are retained for a fixed period of time 2. given a previous hash, we can retrieve a previous state from the map, if it is still retained.

Index

• type Ledger
  • func Make(retention time.Duration) Ledger

Types

type Ledger

type Ledger interface {
	// Put adds or overwrites a key in the Ledger
	Put(key, value string) (string, error)
	// Delete removes a key from the Ledger, which may still be read using GetPreviousValue
	Delete(key string) error
	// Get returns a the value of the key from the Ledger's current state
	Get(key string) (string, error)
	// RootHash is the hash of all keys and values currently in the Ledger
	RootHash() string
	// GetPreviousValue executes a get against a previous version of the ledger, using that version's root hash.
	GetPreviousValue(previousRootHash, key string) (result string, err error)
}

Ledger exposes a modified map with three unique characteristics: 1. every unique state of the map is given a unique hash 2. prior states of the map are retained for a fixed period of time 2. given a previous hash, we can retrieve a previous state from the map, if it is still retained.

func Make

func Make(retention time.Duration) Ledger

Make returns a Ledger which will retain previous nodes after they are deleted.