66 lines
2.2 KiB
Rust
66 lines
2.2 KiB
Rust
//! The Epoch Accounts Hash (EAH) is a special hash of the whole accounts state that occurs once
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//! per epoch.
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//!
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//! This hash is special because all nodes in the cluster will calculate the accounts hash at a
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//! predetermined slot in the epoch and then save that result into a later Bank at a predetermined
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//! slot.
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//!
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//! This results in all nodes effectively voting on the accounts state (at least) once per epoch.
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use {
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crate::bank::Bank,
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serde::{Deserialize, Serialize},
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solana_sdk::{clock::Slot, hash::Hash},
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};
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/// The EpochAccountsHash holds the result after calculating the accounts hash once per epoch
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#[derive(Debug, Serialize, Deserialize, Hash, PartialEq, Eq, Clone, Copy)]
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pub struct EpochAccountsHash(Hash);
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impl AsRef<Hash> for EpochAccountsHash {
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fn as_ref(&self) -> &Hash {
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&self.0
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}
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}
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impl EpochAccountsHash {
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/// Make an EpochAccountsHash from a regular accounts hash
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#[must_use]
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pub fn new(accounts_hash: Hash) -> Self {
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Self(accounts_hash)
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}
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}
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/// Calculation of the EAH occurs once per epoch. All nodes in the cluster must agree on which
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/// slot the EAH is based on. This slot will be at an offset into the epoch, and referred to as
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/// the "start" slot for the EAH calculation.
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#[must_use]
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#[allow(dead_code)]
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pub fn calculation_offset_start(bank: &Bank) -> Slot {
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let slots_per_epoch = bank.epoch_schedule().slots_per_epoch;
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slots_per_epoch / 4
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}
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/// Calculation of the EAH occurs once per epoch. All nodes in the cluster must agree on which
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/// bank will hash the EAH into its `Bank::hash`. This slot will be at an offset into the epoch,
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/// and referred to as the "stop" slot for the EAH calculation. All nodes must complete the EAH
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/// calculation before this slot!
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#[must_use]
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pub fn calculation_offset_stop(bank: &Bank) -> Slot {
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let slots_per_epoch = bank.epoch_schedule().slots_per_epoch;
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slots_per_epoch / 4 * 3
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn test_calculation_offset_bounds() {
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let bank = Bank::default_for_tests();
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let start = calculation_offset_start(&bank);
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let stop = calculation_offset_stop(&bank);
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assert!(start < stop);
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}
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}
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