Crate themelio_stf

themelio-stf: themelio’s core state transition function

This crate contains the data structures and core algorithms that comprise Themelio’s core state transition function. Any piece of software needing to validate Themelio transactions or answer questions like “what happens to the Themelio state if transactions A, B, and C happen” can use this minimal-dependency crate.

The State type

The most important type in the crate is State, and the closely associated type SealedState. The yellow paper talks about them further, but in short:

• State represents an mutable Themelio world-state and it’s not directly serializable. It includes all the information needed to validate new transactions and blocks, such as a SMT of all outstanding coins, Melmint parameters, etc. It has methods taking Transactions etc that advance the state, as well as others to produce serializable blocks, headers, etc.
• SealedState represents a sealed state. This roughly corresponds to the notion of “the blockchain state at a given height”. Blocks represent transitions from one SealedState to another.

Note

This crate is the most consensus-critical part of Themelio, and essentially defines the entire on-chain logic of the Themelio blockchain.

Versions incompatible with the latest Themelio state are thus all yanked.

Modules

melvm

stats

tip_heights

Structs

CoinMapping

A mapping that contains the coins, exposing a safeish API for the rest of the crate.

ConfirmedState

ConfirmedState represents a fully confirmed state with a consensus proof.

GenesisConfig

Configuration of a genesis state. Serializable via serde.

LegacyMelPowHash

Legacy MelPoW hasher

SealedState

SealedState represents an immutable state at a finalized block height. It cannot be constructed except through sealing a State or restoring from persistent storage.

SmtMapping

SmtMapping is a type-safe, constant-time cloneable, imperative-style interface to a sparse Merkle tree.

State

World state of the Themelio blockchain

Tip910MelPowHash

New (TIP-910) MelPoW hasher

Enums

StateError

A error that happens while applying a transaction to a state

Functions

calculate_reward

Reward calculator. Returns the value in real DOSC.

dosc_inflator

DOSC inflation ratio.

dosc_to_erg

DOSC inflation calculator.

preseal_melmint

Presealing function that is called before a state is sealed to apply melmint actions.

Type Definitions

PoolMapping

A pool

StakeMapping

A stake mapping