Split substrate-finality-grandpa

core/finality-grandpa/src/consensus_changes.rs

@@ -0,0 +1,69 @@
+// Copyright 2018-2019 Parity Technologies (UK) Ltd.
+// This file is part of Substrate.
+
+// Substrate 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.
+
+// Substrate 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 Substrate.  If not, see <http://www.gnu.org/licenses/>.
+
+use std::sync::Arc;
+
+/// Consensus-related data changes tracker.
+#[derive(Clone, Debug, Encode, Decode)]
+pub(crate) struct ConsensusChanges<H, N> {
+	pending_changes: Vec<(N, H)>,
+}
+
+impl<H: Copy + PartialEq, N: Copy + Ord> ConsensusChanges<H, N> {
+	/// Create empty consensus changes.
+	pub(crate) fn empty() -> Self {
+		ConsensusChanges { pending_changes: Vec::new(), }
+	}
+
+	/// Note unfinalized change of consensus-related data.
+	pub(crate) fn note_change(&mut self, at: (N, H)) {
+		let idx = self.pending_changes
+			.binary_search_by_key(&at.0, |change| change.0)
+			.unwrap_or_else(|i| i);
+		self.pending_changes.insert(idx, at);
+	}
+
+	/// Finalize all pending consensus changes that are finalized by given block.
+	/// Returns true if there any changes were finalized.
+	pub(crate) fn finalize<F: Fn(N) -> ::client::error::Result<Option<H>>>(
+		&mut self,
+		block: (N, H),
+		canonical_at_height: F,
+	) -> ::client::error::Result<(bool, bool)> {
+		let (split_idx, has_finalized_changes) = self.pending_changes.iter()
+			.enumerate()
+			.take_while(|(_, &(at_height, _))| at_height <= block.0)
+			.fold((None, Ok(false)), |(_, has_finalized_changes), (idx, ref at)|
+				(
+					Some(idx),
+					has_finalized_changes
+						.and_then(|has_finalized_changes| if has_finalized_changes {
+							Ok(has_finalized_changes)
+						} else {
+							canonical_at_height(at.0).map(|can_hash| Some(at.1) == can_hash)
+						}),
+				));
+
+		let altered_changes = split_idx.is_some();
+		if let Some(split_idx) = split_idx {
+			self.pending_changes = self.pending_changes.split_off(split_idx + 1);
+		}
+		has_finalized_changes.map(|has_finalized_changes| (altered_changes, has_finalized_changes))
+	}
+}
+
+/// Thread-safe consensus changes tracker reference.
+pub(crate) type SharedConsensusChanges<H, N> = Arc<parking_lot::Mutex<ConsensusChanges<H, N>>>;