177 lines
6.4 KiB
Rust
177 lines
6.4 KiB
Rust
use {
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super::EpochAccountsHash,
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solana_sdk::clock::Slot,
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std::sync::{Condvar, Mutex},
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};
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/// Manage the epoch accounts hash
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///
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/// Handles setting when an EAH calculation is requested and when it completes. Also handles
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/// waiting for in-flight calculations to complete when the "stop" Bank must include it.
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#[derive(Debug)]
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pub struct Manager {
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/// Current state of the epoch accounts hash
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state: Mutex<State>,
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/// This condition variable is used to wait for an in-flight EAH calculation to complete
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cvar: Condvar,
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}
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impl Manager {
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#[must_use]
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fn _new(state: State) -> Self {
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Self {
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state: Mutex::new(state),
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cvar: Condvar::new(),
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}
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}
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/// Create a new epoch accounts hash manager, with the initial state set to Invalid
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#[must_use]
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pub fn new_invalid() -> Self {
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Self::_new(State::Invalid)
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}
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/// Create a new epoch accounts hash manager, with the initial state set to Valid
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#[must_use]
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pub fn new_valid(epoch_accounts_hash: EpochAccountsHash, slot: Slot) -> Self {
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Self::_new(State::Valid(epoch_accounts_hash, slot))
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}
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/// An epoch accounts hash calculation has been requested; update our state
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pub fn set_in_flight(&self, slot: Slot) {
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let mut state = self.state.lock().unwrap();
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if let State::InFlight(old_slot) = &*state {
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panic!("An epoch accounts hash calculation is already in-flight from slot {old_slot}!");
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}
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*state = State::InFlight(slot);
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}
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/// An epoch accounts hash calculation has completed; update our state
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pub fn set_valid(&self, epoch_accounts_hash: EpochAccountsHash, slot: Slot) {
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let mut state = self.state.lock().unwrap();
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if let State::Valid(old_epoch_accounts_hash, old_slot) = &*state {
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panic!(
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"The epoch accounts hash is already valid! \
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\nold slot: {old_slot}, epoch accounts hash: {old_epoch_accounts_hash:?} \
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\nnew slot: {slot}, epoch accounts hash: {epoch_accounts_hash:?}"
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);
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}
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*state = State::Valid(epoch_accounts_hash, slot);
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self.cvar.notify_all();
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}
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/// Get the epoch accounts hash
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///
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/// If an EAH calculation is in-flight, then this call will block until it completes.
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pub fn wait_get_epoch_accounts_hash(&self) -> EpochAccountsHash {
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let mut state = self.state.lock().unwrap();
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loop {
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match &*state {
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State::Valid(epoch_accounts_hash, _slot) => break *epoch_accounts_hash,
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State::InFlight(_slot) => state = self.cvar.wait(state).unwrap(),
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State::Invalid => panic!("The epoch accounts hash cannot be awaited when Invalid!"),
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}
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}
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}
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/// Get the epoch accounts hash
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///
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/// This fn does not block, and will only yield an EAH if the state is `Valid`
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pub fn try_get_epoch_accounts_hash(&self) -> Option<EpochAccountsHash> {
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let state = self.state.lock().unwrap();
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match &*state {
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State::Valid(epoch_accounts_hash, _slot) => Some(*epoch_accounts_hash),
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_ => None,
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}
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}
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}
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/// The EpochAccountsHash is calculated in the background via AccountsBackgroundService. This enum
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/// is used to track the state of that calculation, and queried when saving the EAH into a Bank or
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/// Snapshot.
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#[derive(Debug, Clone, Copy, PartialEq, Eq)]
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enum State {
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/// The initial state of the EAH. This can occur when loading from a snapshot that does not
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/// include an EAH, or when starting from genesis (before an EAH calculation is requested).
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Invalid,
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/// An EAH calculation has been requested (for `Slot`) and is in flight. The Bank that should
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/// save the EAH must wait until the calculation has completed.
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InFlight(Slot),
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/// The EAH calculation is complete (for `Slot`) and the EAH value is valid to read/use.
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Valid(EpochAccountsHash, Slot),
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}
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#[cfg(test)]
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mod tests {
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use {super::*, solana_sdk::hash::Hash, std::time::Duration};
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#[test]
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fn test_new_valid() {
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let epoch_accounts_hash = EpochAccountsHash::new(Hash::new_unique());
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let manager = Manager::new_valid(epoch_accounts_hash, 5678);
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assert_eq!(
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manager.try_get_epoch_accounts_hash(),
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Some(epoch_accounts_hash),
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);
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assert_eq!(manager.wait_get_epoch_accounts_hash(), epoch_accounts_hash);
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}
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#[test]
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fn test_new_invalid() {
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let manager = Manager::new_invalid();
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assert!(manager.try_get_epoch_accounts_hash().is_none());
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}
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#[test]
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fn test_try_get_epoch_accounts_hash() {
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let epoch_accounts_hash = EpochAccountsHash::new(Hash::new_unique());
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for (state, expected) in [
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(State::Invalid, None),
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(State::InFlight(123), None),
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(
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State::Valid(epoch_accounts_hash, 5678),
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Some(epoch_accounts_hash),
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),
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] {
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let manager = Manager::_new(state);
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let actual = manager.try_get_epoch_accounts_hash();
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assert_eq!(actual, expected);
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}
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}
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#[test]
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fn test_wait_epoch_accounts_hash() {
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// Test: State is Valid, no need to wait
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{
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let epoch_accounts_hash = EpochAccountsHash::new(Hash::new_unique());
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let manager = Manager::new_valid(epoch_accounts_hash, 5678);
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assert_eq!(manager.wait_get_epoch_accounts_hash(), epoch_accounts_hash);
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}
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// Test: State is InFlight, must wait
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{
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let epoch_accounts_hash = EpochAccountsHash::new(Hash::new_unique());
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let manager = Manager::new_invalid();
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manager.set_in_flight(123);
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std::thread::scope(|s| {
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s.spawn(|| {
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std::thread::sleep(Duration::from_secs(1));
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manager.set_valid(epoch_accounts_hash, 5678)
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});
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assert!(manager.try_get_epoch_accounts_hash().is_none());
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assert_eq!(manager.wait_get_epoch_accounts_hash(), epoch_accounts_hash);
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assert!(manager.try_get_epoch_accounts_hash().is_some());
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});
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}
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}
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#[test]
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#[should_panic]
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fn test_wait_epoch_accounts_hash_invalid() {
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// Test: State is Invalid, should panic
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let manager = Manager::new_invalid();
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let _epoch_accounts_hash = manager.wait_get_epoch_accounts_hash();
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}
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}
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