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Document new BeaconState functions

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This commit is contained in:
Michael Sproul
2019-11-11 16:52:07 +11:00
parent 2651255a89
commit 2ed8eca0c1
4 changed files with 52 additions and 40 deletions
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2
eth2/state_processing/tests/tests.rs
View File

@@ -205,6 +205,4 @@ mod signatures_minimal {
spec,
);
}
// Cannot test transfers because their length is zero.
}

66
eth2/types/src/beacon_state.rs
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@@ -307,17 +307,21 @@ impl<T: EthSpec> BeaconState<T> {
self.current_epoch() + 1
}
// FIXME(sproul): comments
/// Compute the number of committees at `slot`.
///
/// Makes use of the committee cache and will fail if no cache exists for the slot's epoch.
///
/// Spec v0.9.1
pub fn get_committee_count_at_slot(&self, slot: Slot) -> Result<u64, Error> {
// TODO(sproul): factor into cache at slot method?
let epoch = slot.epoch(T::slots_per_epoch());
let relative_epoch = RelativeEpoch::from_epoch(self.current_epoch(), epoch)?;
let cache = self.cache(relative_epoch)?;
let cache = self.committee_cache_at_slot(slot)?;
Ok(cache.committees_per_slot() as u64)
}
/// Compute the number of committees in an entire epoch.
///
/// Spec v0.9.1
pub fn get_epoch_committee_count(&self, relative_epoch: RelativeEpoch) -> Result<u64, Error> {
let cache = self.cache(relative_epoch)?;
let cache = self.committee_cache(relative_epoch)?;
Ok(cache.epoch_committee_count() as u64)
}
@@ -330,7 +334,7 @@ impl<T: EthSpec> BeaconState<T> {
&self,
relative_epoch: RelativeEpoch,
) -> Result<&[usize], Error> {
let cache = self.cache(relative_epoch)?;
let cache = self.committee_cache(relative_epoch)?;
Ok(&cache.active_validator_indices())
}
@@ -350,13 +354,15 @@ impl<T: EthSpec> BeaconState<T> {
///
/// Returns an error if that epoch is not cached, or the cache is not initialized.
pub fn get_shuffling(&self, relative_epoch: RelativeEpoch) -> Result<&[usize], Error> {
let cache = self.cache(relative_epoch)?;
let cache = self.committee_cache(relative_epoch)?;
Ok(cache.shuffling())
}
/// Get the Beacon committee at the given slot and index.
///
/// Utilises the committee cache.
///
/// Spec v0.9.1
pub fn get_beacon_committee(
&self,
@@ -365,18 +371,20 @@ impl<T: EthSpec> BeaconState<T> {
) -> Result<BeaconCommittee, Error> {
let epoch = slot.epoch(T::slots_per_epoch());
let relative_epoch = RelativeEpoch::from_epoch(self.current_epoch(), epoch)?;
let cache = self.cache(relative_epoch)?;
let cache = self.committee_cache(relative_epoch)?;
cache
.get_beacon_committee(slot, index)
.ok_or(Error::NoCommittee { slot, index })
}
// TODO(sproul): optimise?
/// Get all of the Beacon committees at a given slot.
///
/// Utilises the committee cache.
///
/// Spec v0.9.1
pub fn get_beacon_committees_at_slot(&self, slot: Slot) -> Result<Vec<BeaconCommittee>, Error> {
let epoch = slot.epoch(T::slots_per_epoch());
let relative_epoch = RelativeEpoch::from_epoch(self.current_epoch(), epoch)?;
let cache = self.cache(relative_epoch)?;
let cache = self.committee_cache_at_slot(slot)?;
cache.get_beacon_committees_at_slot(slot)
}
@@ -697,7 +705,8 @@ impl<T: EthSpec> BeaconState<T> {
pub fn get_churn_limit(&self, spec: &ChainSpec) -> Result<u64, Error> {
Ok(std::cmp::max(
spec.min_per_epoch_churn_limit,
self.cache(RelativeEpoch::Current)?.active_validator_count() as u64
self.committee_cache(RelativeEpoch::Current)?
.active_validator_count() as u64
/ spec.churn_limit_quotient,
))
}
@@ -713,7 +722,7 @@ impl<T: EthSpec> BeaconState<T> {
validator_index: usize,
relative_epoch: RelativeEpoch,
) -> Result<Option<AttestationDuty>, Error> {
let cache = self.cache(relative_epoch)?;
let cache = self.committee_cache(relative_epoch)?;
Ok(cache.get_attestation_duties(validator_index))
}
@@ -760,7 +769,7 @@ impl<T: EthSpec> BeaconState<T> {
relative_epoch: RelativeEpoch,
spec: &ChainSpec,
) -> Result<(), Error> {
let i = Self::cache_index(relative_epoch);
let i = Self::committee_cache_index(relative_epoch);
if self.committee_caches[i]
.is_initialized_at(relative_epoch.into_epoch(self.current_epoch()))
@@ -779,7 +788,7 @@ impl<T: EthSpec> BeaconState<T> {
) -> Result<(), Error> {
let epoch = relative_epoch.into_epoch(self.current_epoch());
self.committee_caches[Self::cache_index(relative_epoch)] =
self.committee_caches[Self::committee_cache_index(relative_epoch)] =
CommitteeCache::initialized(&self, epoch, spec)?;
Ok(())
}
@@ -790,8 +799,8 @@ impl<T: EthSpec> BeaconState<T> {
///
/// Note: whilst this function will preserve already-built caches, it will not build any.
pub fn advance_caches(&mut self) {
let next = Self::cache_index(RelativeEpoch::Previous);
let current = Self::cache_index(RelativeEpoch::Current);
let next = Self::committee_cache_index(RelativeEpoch::Previous);
let current = Self::committee_cache_index(RelativeEpoch::Current);
let caches = &mut self.committee_caches[..];
caches.rotate_left(1);
@@ -799,7 +808,7 @@ impl<T: EthSpec> BeaconState<T> {
caches[current] = CommitteeCache::default();
}
fn cache_index(relative_epoch: RelativeEpoch) -> usize {
fn committee_cache_index(relative_epoch: RelativeEpoch) -> usize {
match relative_epoch {
RelativeEpoch::Previous => 0,
RelativeEpoch::Current => 1,
@@ -807,11 +816,19 @@ impl<T: EthSpec> BeaconState<T> {
}
}
/// Get the committee cache for some `slot`.
///
/// Return an error if the cache for the slot's epoch is not initialized.
fn committee_cache_at_slot(&self, slot: Slot) -> Result<&CommitteeCache, Error> {
let epoch = slot.epoch(T::slots_per_epoch());
let relative_epoch = RelativeEpoch::from_epoch(self.current_epoch(), epoch)?;
self.committee_cache(relative_epoch)
}
/// Returns the cache for some `RelativeEpoch`. Returns an error if the cache has not been
/// initialized.
// FIXME(sproul): rename to commitee_cache
fn cache(&self, relative_epoch: RelativeEpoch) -> Result<&CommitteeCache, Error> {
let cache = &self.committee_caches[Self::cache_index(relative_epoch)];
fn committee_cache(&self, relative_epoch: RelativeEpoch) -> Result<&CommitteeCache, Error> {
let cache = &self.committee_caches[Self::committee_cache_index(relative_epoch)];
if cache.is_initialized_at(relative_epoch.into_epoch(self.current_epoch())) {
Ok(cache)
@@ -822,7 +839,8 @@ impl<T: EthSpec> BeaconState<T> {
/// Drops the cache, leaving it in an uninitialized state.
fn drop_committee_cache(&mut self, relative_epoch: RelativeEpoch) {
self.committee_caches[Self::cache_index(relative_epoch)] = CommitteeCache::default();
self.committee_caches[Self::committee_cache_index(relative_epoch)] =
CommitteeCache::default();
}
/// Updates the pubkey cache, if required.

21
eth2/types/src/beacon_state/committee_cache.rs
View File

@@ -101,12 +101,18 @@ impl CommitteeCache {
&self.shuffling
}
/// Get the Beacon committee for the given `slot` and `index`.
///
/// Return `None` if the cache is uninitialized, or the `slot` or `index` is out of range.
pub fn get_beacon_committee(
&self,
slot: Slot,
index: CommitteeIndex,
) -> Option<BeaconCommittee> {
if self.initialized_epoch.is_none() || index >= self.committees_per_slot {
if self.initialized_epoch.is_none()
|| !self.is_initialized_at(slot.epoch(self.slots_per_epoch))
|| index >= self.committees_per_slot
{
return None;
}
@@ -121,6 +127,7 @@ impl CommitteeCache {
})
}
/// Get all the Beacon committees at a given `slot`.
pub fn get_beacon_committees_at_slot(&self, slot: Slot) -> Result<Vec<BeaconCommittee>, Error> {
if self.initialized_epoch.is_none() {
return Err(Error::CommitteeCacheUninitialized(None));
@@ -165,6 +172,7 @@ impl CommitteeCache {
})
}
/// Convert an index addressing the list of all epoch committees into a slot and per-slot index.
fn convert_to_slot_and_index(
&self,
global_committee_index: u64,
@@ -193,6 +201,7 @@ impl CommitteeCache {
self.committees_per_slot as usize * self.slots_per_epoch as usize
}
/// Returns the number of committees per slot for this cache's epoch.
pub fn committees_per_slot(&self) -> u64 {
self.committees_per_slot
}
@@ -251,13 +260,3 @@ pub fn get_active_validator_indices(validators: &[Validator], epoch: Epoch) -> V
active
}
/*
/// Returns the count of all `validators` indices where the validator is active at the given
/// `epoch`.
///
/// Spec v0.9.1
fn get_active_validator_count(validators: &[Validator], epoch: Epoch) -> usize {
validators.iter().filter(|v| v.is_active_at(epoch)).count()
}
*/

3
eth2/types/src/beacon_state/tests.rs
View File

@@ -44,7 +44,6 @@ fn test_beacon_proposer_index<T: EthSpec>() {
// 0th candidate should be chosen every time.
let state = build_state(T::slots_per_epoch() as usize);
for i in 0..T::slots_per_epoch() {
println!("i = {}", i);
test(&state, Slot::from(i), 0);
}
@@ -52,7 +51,6 @@ fn test_beacon_proposer_index<T: EthSpec>() {
// 0th candidate should be chosen every time.
let state = build_state(T::slots_per_epoch() as usize * 2);
for i in 0..T::slots_per_epoch() {
println!("i = {}", i);
test(&state, Slot::from(i), 0);
}
@@ -62,7 +60,6 @@ fn test_beacon_proposer_index<T: EthSpec>() {
state.validators[slot0_candidate0].effective_balance = 0;
test(&state, Slot::new(0), 1);
for i in 1..T::slots_per_epoch() {
println!("i = {}", i);
test(&state, Slot::from(i), 0);
}
}