Single-pass epoch processing (#4483)

consensus/state_processing/src/all_caches.rs

@@ -0,0 +1,55 @@
+use crate::common::update_progressive_balances_cache::initialize_progressive_balances_cache;
+use crate::epoch_cache::initialize_epoch_cache;
+use types::{BeaconState, ChainSpec, EpochCacheError, EthSpec, Hash256, RelativeEpoch};
+
+/// Mixin trait for the beacon state that provides operations on *all* caches.
+///
+/// The reason this trait exists here away from `BeaconState` itself is that some caches are
+/// computed by functions in `state_processing`.
+pub trait AllCaches {
+    /// Build all caches.
+    ///
+    /// Note that this excludes milhouse's intrinsic tree-hash cache. That needs to be managed
+    /// separately.
+    fn build_all_caches(&mut self, spec: &ChainSpec) -> Result<(), EpochCacheError>;
+
+    /// Return true if all caches are built.
+    ///
+    /// Note that this excludes milhouse's intrinsic tree-hash cache. That needs to be managed
+    /// separately.
+    fn all_caches_built(&self) -> bool;
+}
+
+impl<E: EthSpec> AllCaches for BeaconState<E> {
+    fn build_all_caches(&mut self, spec: &ChainSpec) -> Result<(), EpochCacheError> {
+        self.build_caches(spec)?;
+        initialize_epoch_cache(self, spec)?;
+        initialize_progressive_balances_cache(self, None, spec)?;
+        Ok(())
+    }
+
+    fn all_caches_built(&self) -> bool {
+        let current_epoch = self.current_epoch();
+        let epoch_cache_decision_block_root =
+            if let Ok(root) = self.proposer_shuffling_decision_root(Hash256::zero()) {
+                root
+            } else {
+                return false;
+            };
+        self.get_total_active_balance_at_epoch(current_epoch)
+            .is_ok()
+            && self.committee_cache_is_initialized(RelativeEpoch::Previous)
+            && self.committee_cache_is_initialized(RelativeEpoch::Current)
+            && self.committee_cache_is_initialized(RelativeEpoch::Next)
+            && self
+                .progressive_balances_cache()
+                .is_initialized_at(current_epoch)
+            && self.pubkey_cache().len() == self.validators().len()
+            && self.exit_cache().check_initialized().is_ok()
+            && self.slashings_cache_is_initialized()
+            && self
+                .epoch_cache()
+                .check_validity::<E>(current_epoch, epoch_cache_decision_block_root)
+                .is_ok()
+    }
+}