Finality loop: get block justification and authorities change by consensus engine ID (#1619)

* SignedBlock: get justification by consensus engine id

* Define ConsensusLogReader

Making the check for authority changes more generic

* cod review changes

bridges/relays/client-substrate/src/chain.rs

@@ -27,7 +27,7 @@ use sp_core::{storage::StorageKey, Pair};
 use sp_runtime::{
 	generic::SignedBlock,
 	traits::{Block as BlockT, Dispatchable, Member},
-	EncodedJustification,
+	ConsensusEngineId, EncodedJustification,
 };
 use std::{fmt::Debug, time::Duration};
 
@@ -147,7 +147,7 @@ pub trait BlockWithJustification<Header> {
 	/// Return encoded block extrinsics.
 	fn extrinsics(&self) -> Vec<EncodedExtrinsic>;
 	/// Return block justification, if known.
-	fn justification(&self) -> Option<&EncodedJustification>;
+	fn justification(&self, engine_id: ConsensusEngineId) -> Option<&EncodedJustification>;
 }
 
 /// Transaction before it is signed.
@@ -237,9 +237,7 @@ impl<Block: BlockT> BlockWithJustification<Block::Header> for SignedBlock<Block>
 		self.block.extrinsics().iter().map(Encode::encode).collect()
 	}
 
-	fn justification(&self) -> Option<&EncodedJustification> {
-		self.justifications
-			.as_ref()
-			.and_then(|j| j.get(sp_finality_grandpa::GRANDPA_ENGINE_ID))
+	fn justification(&self, engine_id: ConsensusEngineId) -> Option<&EncodedJustification> {
+		self.justifications.as_ref().and_then(|j| j.get(engine_id))
 	}
 }

bridges/relays/client-substrate/src/sync_header.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity Bridges Common.  If not, see <http://www.gnu.org/licenses/>.
 
-use bp_header_chain::find_grandpa_authorities_scheduled_change;
+use bp_header_chain::ConsensusLogReader;
 use finality_relay::SourceHeader as FinalitySourceHeader;
 use sp_runtime::traits::Header as HeaderT;
 
@@ -44,7 +44,9 @@ impl<Header> From<Header> for SyncHeader<Header> {
 	}
 }
 
-impl<Header: HeaderT> FinalitySourceHeader<Header::Hash, Header::Number> for SyncHeader<Header> {
+impl<Header: HeaderT, R: ConsensusLogReader> FinalitySourceHeader<Header::Hash, Header::Number, R>
+	for SyncHeader<Header>
+{
 	fn hash(&self) -> Header::Hash {
 		self.0.hash()
 	}
@@ -54,6 +56,6 @@ impl<Header: HeaderT> FinalitySourceHeader<Header::Hash, Header::Number> for Syn
 	}
 
 	fn is_mandatory(&self) -> bool {
-		find_grandpa_authorities_scheduled_change(&self.0).is_some()
+		R::schedules_authorities_change(self.digest())
 	}
 }