Struct TransactionCertifier

pub struct TransactionCertifier { /* private fields */ }

TransactionCertifier has the following purposes:

1. Certifies transactions and sends them to execute on the fastpath.
2. Keeps track of own votes on transactions, and allows the votes to be retrieved later in core after acceptance of the blocks containing the transactions.
3. Aggregates reject votes on transactions, and allows the aggregated votes to be retrieved during post-commit finalization.

A transaction is certified if a quorum of authorities in the causal history of a proposed block vote to accept the transaction. Accept votes are implicit in blocks: if a transaction is in the causal history of a block and the block does not vote to reject it, the block is considered to vote to accept the transaction. Transaction finalization are eventually resolved post commit, by checking if there is a certification of the transaction in the causal history of the leader. So only accept votes are only considered if they are in the causal history of own proposed blocks.

A transaction is rejected if a quorum of authorities vote to reject it. When this happens, it is guaranteed that no validator can observe a certification of the transaction, with <= f malicious stake.

A block is certified if every transaction in the block is either certified or rejected. TransactionCertifier outputs certified blocks.

The invariant between TransactionCertifier and post-commit finalization is that if a quorum of authorities certified a transaction for fastpath and executed it, then the transaction must also be finalized post consensus commit. The reverse is not true though, because fastpath execution is only a latency optimization, and not required for correctness.

Implementations

impl TransactionCertifier

pub fn new( context: Arc<Context>, dag_state: Arc<RwLock<DagState>>, certified_blocks_sender: UnboundedSender<CertifiedBlocksOutput>, ) -> Self

pub fn add_voted_blocks( &self, voted_blocks: Vec<(VerifiedBlock, Vec<TransactionIndex>)>, )

Stores own reject votes on input blocks, and aggregates reject votes from the input blocks. Newly certified blocks are sent to the fastpath output channel.

Trait Implementations

impl Clone for TransactionCertifier

fn clone(&self) -> TransactionCertifier

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.