Handle block vote cache

runtime/src/state.rs

@@ -22,7 +22,7 @@ pub struct ActiveState {
 	pub recent_block_hashes: Vec<H256>,
 }
 
-#[derive(Encode, Decode)]
+#[derive(Encode, Decode, Default)]
 pub struct BlockVoteInfo {
 	pub voter_indices: Vec<usize>,
 	pub total_voter_deposits: u128,

runtime/src/validation.rs

 use primitives::H256;
 use runtime_support::storage::StorageMap;
 
-use state::{ActiveState, CrystallizedState};
+use state::{ActiveState, CrystallizedState, BlockVoteInfo};
 use attestation::AttestationRecord;
 use consts::CYCLE_LENGTH;
 
@@ -48,3 +48,28 @@ pub fn validate_attestation<JustifiedBlockHashes: StorageMap<u64, H256, Query=Op
 
 	attestation.verify_signatures(&parent_hashes, &pubkeys);
 }
+
+pub fn update_block_vote_cache<BlockVoteCache: StorageMap<H256, BlockVoteInfo, Query=Option<BlockVoteInfo>>>(
+	slot: u64,
+	crystallized_state: &CrystallizedState,
+	active_state: &ActiveState,
+	attestation: &AttestationRecord
+) {
+	let parent_hashes = active_state.signed_parent_block_hashes(slot, attestation);
+	let attestation_indices = crystallized_state.attestation_indices(attestation);
+
+	for parent_hash in parent_hashes {
+		if attestation.oblique_parent_hashes.contains(&parent_hash) {
+			continue;
+		}
+
+		let mut info = BlockVoteCache::get(&parent_hash).unwrap_or_default();
+		for (i, index) in attestation_indices.iter().enumerate() {
+			if attestation.attester_bitfield.has_voted(i) && !info.voter_indices.contains(index) {
+				info.voter_indices.push(*index);
+				info.total_voter_deposits += crystallized_state.validators[*index].balance;
+			}
+		}
+		BlockVoteCache::insert(parent_hash, info);
+	}
+}