Substrate relay stub (#376)

* substrate-relay: initial commit

* MillauHeaderApi and RialtoHeaderApi

* post-merge fixes + TODOs + compilation

bridges/relays/millau-client/Cargo.toml

@@ -6,5 +6,16 @@ edition = "2018"
 license = "GPL-3.0-or-later WITH Classpath-exception-2.0"
 
 [dependencies]
+codec = { package = "parity-scale-codec", version = "1.3.4" }
+headers-relay = { path = "../headers-relay" }
+relay-substrate-client = { path = "../substrate-client" }
+relay-utils = { path = "../utils" }
+
+# Supported Chains
+
 millau-runtime = { path = "../../bin/millau-runtime" }
-substrate-client = { path = "../substrate-client" }
+
+# Substrate Dependencies
+
+frame-system = { version = "2.0.0", tag = 'v2.0.0', git = "https://github.com/paritytech/substrate.git" }
+sp-runtime = { version = "2.0.0", tag = 'v2.0.0', git = "https://github.com/paritytech/substrate.git" }

bridges/relays/millau-client/src/lib.rs

@@ -18,6 +18,12 @@
 
 use relay_substrate_client::Chain;
 
+use headers_relay::sync_types::SourceHeader;
+use sp_runtime::traits::Header as HeaderT;
+
+/// Millau header id.
+pub type HeaderId = relay_utils::HeaderId<millau_runtime::Hash, millau_runtime::BlockNumber>;
+
 /// Millau chain definition.
 #[derive(Debug, Clone, Copy)]
 pub struct Millau;
@@ -29,5 +35,33 @@ impl Chain for Millau {
 	type AccountId = millau_runtime::AccountId;
 	type Index = millau_runtime::Index;
 	type SignedBlock = millau_runtime::SignedBlock;
-	type Call = rialto_runtime::Call;
+	type Call = millau_runtime::Call;
+}
+
+/// Millau header type used in headers sync.
+#[derive(Clone, Debug, PartialEq)]
+pub struct SyncHeader(millau_runtime::Header);
+
+impl std::ops::Deref for SyncHeader {
+	type Target = millau_runtime::Header;
+
+	fn deref(&self) -> &Self::Target {
+		&self.0
+	}
+}
+
+impl From<millau_runtime::Header> for SyncHeader {
+	fn from(header: millau_runtime::Header) -> Self {
+		Self(header)
+	}
+}
+
+impl SourceHeader<millau_runtime::Hash, millau_runtime::BlockNumber> for SyncHeader {
+	fn id(&self) -> HeaderId {
+		relay_utils::HeaderId(*self.number(), self.hash())
+	}
+
+	fn parent_id(&self) -> HeaderId {
+		relay_utils::HeaderId(*self.number(), *self.parent_hash())
+	}
 }