beacon: compact_committees_root

beacon/src/config.rs

@@ -21,7 +21,7 @@ use serde::{Serialize, Deserialize};
 use crate::primitives::{H256, Uint, Signature, ValidatorId};
 
 /// BLS operations
-pub trait BLSVerification: Clone + 'static {
+pub trait BLSVerification: Default + Clone + 'static {
 	/// Verify BLS signature.
 	fn verify(pubkey: &ValidatorId, message: &H256, signature: &Signature, domain: u64) -> bool;
 	/// Aggregate BLS public keys.
@@ -33,7 +33,7 @@ pub trait BLSVerification: Clone + 'static {
 }
 
 /// Run bls without any verification.
-#[derive(Clone, PartialEq, Eq)]
+#[derive(Default, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "std", derive(Debug))]
 pub struct BLSNoVerification;
 
@@ -53,7 +53,7 @@ impl BLSVerification for BLSNoVerification {
 }
 
 /// Constants used in beacon block.
-pub trait Config: Clone + 'static {
+pub trait Config: Default + Clone + 'static {
 	/// Digest hash function.
 	type Digest: Digest<OutputSize=typenum::U32>;
 	type MaxValidatorsPerCommittee: Unsigned + core::fmt::Debug + Clone + Eq + PartialEq + Default;
@@ -212,7 +212,7 @@ pub trait Config: Clone + 'static {
 	}
 }
 
-#[derive(Clone, PartialEq, Eq)]
+#[derive(Default, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "std", derive(Debug))]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct MinimalConfig<BLS>(PhantomData<BLS>);
@@ -300,7 +300,7 @@ impl<BLS: BLSVerification> Config for MinimalConfig<BLS> {
 	}
 }
 
-#[derive(Clone, PartialEq, Eq)]
+#[derive(Default, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "std", derive(Debug))]
 #[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
 pub struct MainnetConfig<BLS>(PhantomData<BLS>);

beacon/src/executive/helpers/accessors.rs

 use crate::types::*;
 use crate::primitives::*;
 use crate::{BeaconState, Config, Error, utils};
+use vecarray::VecArray;
+use bm_le::tree_root;
 use core::cmp::{max, min};
 
 impl<C: Config> BeaconState<C> {
@@ -165,6 +167,25 @@ impl<C: Config> BeaconState<C> {
 		   offset / (committee_count / C::slots_per_epoch()))
 	}
 
+	pub fn compact_committees_root(&self, epoch: Uint) -> Result<H256, Error> {
+		let mut committees = VecArray::<CompactCommittee<C>, C::ShardCount>::default();
+		let start_shard = self.start_shard(epoch)?;
+
+		for committee_number in 0..self.committee_count(epoch) {
+			let shard = (start_shard + committee_number) % C::shard_count();
+			for index in self.crosslink_committee(epoch, shard)? {
+				let validator = &self.validators[index as usize];
+				committees[shard as usize].pubkeys.push(validator.pubkey.clone());
+				let compact_balance = validator.effective_balance / C::effective_balance_increment();
+				let compact_validator = (index << 16) +
+					(if validator.slashed { 1 } else { 0 } << 15) + compact_balance;
+				committees[shard as usize].compact_validators.append(compact_validator);
+			}
+		}
+
+		Ok(tree_root::<C::Digest, _>(&committees))
+	}
+
 	pub fn domain(&self, domain_type: Uint, message_epoch: Option<Uint>) -> Uint {
 		let epoch = message_epoch.unwrap_or(self.current_epoch());
 		let fork_version = if epoch < self.fork.epoch {