Req/res optimization for statement distribution

node/network/protocol/src/lib.rs

@@ -291,7 +291,7 @@ pub mod v1 {
 	use parity_scale_codec::{Encode, Decode};
 	use std::convert::TryFrom;
 
-	use polkadot_primitives::v1::{CandidateHash, CandidateIndex, CollatorId, CollatorSignature, Hash, Id as ParaId, SignedAvailabilityBitfield, ValidatorIndex, ValidatorSignature};
+	use polkadot_primitives::v1::{CandidateHash, CandidateIndex, CollatorId, CollatorSignature, CompactStatement, Hash, Id as ParaId, SignedAvailabilityBitfield, ValidatorIndex, ValidatorSignature};
 	use polkadot_node_primitives::{
 		approval::{IndirectAssignmentCert, IndirectSignedApprovalVote},
 		SignedFullStatement,
@@ -345,6 +345,33 @@ pub mod v1 {
 				Self::LargeStatement(metadata) => metadata.clone(),
 			}
 		}
+
+		/// Get fingerprint describing the contained statement uniquely.
+		pub fn get_fingerprint(&self) -> (CompactStatement, ValidatorIndex) {
+			match self {
+				Self::Statement(_, statement) =>
+					(statement.payload().to_compact(), statement.validator_index()),
+				Self::LargeStatement(meta) =>
+					(CompactStatement::Seconded(meta.candidate_hash), meta.signed_by),
+			}
+		}
+
+		/// Get contained relay parent.
+		pub fn get_relay_parent(&self) -> Hash {
+			match self {
+				Self::Statement(r, _) => *r,
+				Self::LargeStatement(meta) => meta.relay_parent,
+			}
+		}
+
+		/// Whether or not this message contains a large statement.
+		pub fn is_large_statement(&self) -> bool {
+			if let Self::LargeStatement(_) = self {
+				true
+			} else {
+				false
+			}
+		}
 	}
 
 	/// Network messages used by the approval distribution subsystem.