Unify Substrate Bridge Pallet with Finality Verifier (paritytech#783)

* Add relevant storage items from Substrate pallet

* Add function for importing finalized headers to storage

* Remove unused getter functions

* Add GenesisConfig to pallet

* Add initialization extrinsic

* Add operational extrinsic

* Get existing finality verifier tests compiling again

* Add tests for pallet initialization

* Add tests related to pallet's operational status

* Update tests which were using `pallet-substrate-bridge`

* Add tests related to header imports

* Use wrapper function when init-ing some tests

* Add prefix to tests related to rate limiter

* Fix failed compilation related to GenesisConfig

* Add some documentation

* Change some extrinsics to be Operational

* Add public interface to pallet

* Implement runtime APIs for finality-verifier pallet

* Justify use of `expect` when importing headers

* Reject headers with forced changes

* Add weight to initialize extrinsic

* Remove TODO which will be addressed later

* Move succesful import log to correct location

* Expand proof for when `best_finalized` is fetched

* Move check for newer finalized blocks earlier in pipeline

* Rename `ConflictingFork` error to be more generic

* Only compute finality_target's hash once

* Add missing documentation to Runtime APIs

* Add TODO about using `set_id` from `ScheduledChange` digest

bridges/bin/millau/runtime/src/lib.rs

@@ -559,6 +559,17 @@ impl_runtime_apis! {
 		}
 	}
 
+	impl bp_rialto::RialtoFinalityApi<Block> for Runtime {
+		fn best_finalized() -> (bp_rialto::BlockNumber, bp_rialto::Hash) {
+			let header = BridgeFinalityVerifier::best_finalized();
+			(header.number, header.hash())
+		}
+
+		fn is_known_header(hash: bp_rialto::Hash) -> bool {
+			BridgeFinalityVerifier::is_known_header(hash)
+		}
+	}
+
 	impl bp_rialto::ToRialtoOutboundLaneApi<Block, Balance, ToRialtoMessagePayload> for Runtime {
 		fn estimate_message_delivery_and_dispatch_fee(
 			_lane_id: bp_message_lane::LaneId,

bridges/bin/rialto/runtime/src/lib.rs

@@ -642,6 +642,17 @@ impl_runtime_apis! {
 		}
 	}
 
+	impl bp_millau::MillauFinalityApi<Block> for Runtime {
+		fn best_finalized() -> (bp_millau::BlockNumber, bp_millau::Hash) {
+			let header = BridgeFinalityVerifier::best_finalized();
+			(header.number, header.hash())
+		}
+
+		fn is_known_header(hash: bp_millau::Hash) -> bool {
+			BridgeFinalityVerifier::is_known_header(hash)
+		}
+	}
+
 	impl bp_currency_exchange::RialtoCurrencyExchangeApi<Block, exchange::EthereumTransactionInclusionProof> for Runtime {
 		fn filter_transaction_proof(proof: exchange::EthereumTransactionInclusionProof) -> bool {
 			BridgeRialtoCurrencyExchange::filter_transaction_proof(&proof)

bridges/modules/finality-verifier/Cargo.toml

@@ -21,6 +21,7 @@ bp-header-chain = { path = "../../primitives/header-chain", default-features = f
 
 frame-support = { git = "https://github.com/paritytech/substrate.git", branch = "master" , default-features = false }
 frame-system = { git = "https://github.com/paritytech/substrate.git", branch = "master" , default-features = false }
+sp-finality-grandpa = { git = "https://github.com/paritytech/substrate.git", branch = "master" , default-features = false }
 sp-runtime = { git = "https://github.com/paritytech/substrate.git", branch = "master" , default-features = false }
 sp-std = { git = "https://github.com/paritytech/substrate.git", branch = "master" , default-features = false }
 
@@ -40,6 +41,7 @@ std = [
 	"frame-support/std",
 	"frame-system/std",
 	"serde",
+	"sp-finality-grandpa/std",
 	"sp-runtime/std",
 	"sp-std/std",
 ]