Merge commit 'e5bed7ac380b6adb54b60a2a72a2a8f07f50d6c1' as 'bridges'

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

@@ -0,0 +1,73 @@
+// Copyright 2019-2021 Parity Technologies (UK) Ltd.
+// This file is part of Parity Bridges Common.
+
+// Parity Bridges Common is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity Bridges Common is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// 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 finality_relay::SourceHeader as FinalitySourceHeader;
+use headers_relay::sync_types::SourceHeader;
+use num_traits::{CheckedSub, One};
+use relay_utils::HeaderId;
+use sp_runtime::traits::Header as HeaderT;
+
+/// Generic wrapper for `sp_runtime::traits::Header` based headers, that
+/// implements `headers_relay::sync_types::SourceHeader` and may be used in headers sync directly.
+#[derive(Clone, Debug, PartialEq)]
+pub struct SyncHeader<Header>(Header);
+
+impl<Header> SyncHeader<Header> {
+	/// Extracts wrapped header from self.
+	pub fn into_inner(self) -> Header {
+		self.0
+	}
+}
+
+impl<Header> std::ops::Deref for SyncHeader<Header> {
+	type Target = Header;
+
+	fn deref(&self) -> &Self::Target {
+		&self.0
+	}
+}
+
+impl<Header> From<Header> for SyncHeader<Header> {
+	fn from(header: Header) -> Self {
+		Self(header)
+	}
+}
+
+impl<Header: HeaderT> SourceHeader<Header::Hash, Header::Number> for SyncHeader<Header> {
+	fn id(&self) -> HeaderId<Header::Hash, Header::Number> {
+		relay_utils::HeaderId(*self.0.number(), self.hash())
+	}
+
+	fn parent_id(&self) -> HeaderId<Header::Hash, Header::Number> {
+		relay_utils::HeaderId(
+			self.number()
+				.checked_sub(&One::one())
+				.expect("should never be called for genesis header"),
+			*self.parent_hash(),
+		)
+	}
+}
+
+impl<Header: HeaderT> FinalitySourceHeader<Header::Number> for SyncHeader<Header> {
+	fn number(&self) -> Header::Number {
+		*self.0.number()
+	}
+
+	fn is_mandatory(&self) -> bool {
+		find_grandpa_authorities_scheduled_change(&self.0).is_some()
+	}
+}