feat: initialize Kurdistan SDK - independent fork of Polkadot SDK

pezkuwi/node/network/statement-distribution/src/v2/groups.rs

@@ -0,0 +1,74 @@
+// Copyright (C) Parity Technologies (UK) Ltd.
+// This file is part of Pezkuwi.
+
+// Pezkuwi 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.
+
+// Pezkuwi 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 Pezkuwi.  If not, see <http://www.gnu.org/licenses/>.
+
+//! A utility for tracking groups and their members within a session.
+
+use pezkuwi_primitives::{effective_minimum_backing_votes, GroupIndex, IndexedVec, ValidatorIndex};
+
+use std::collections::HashMap;
+
+/// Validator groups within a session, plus some helpful indexing for
+/// looking up groups by validator indices or authority discovery ID.
+#[derive(Debug, Clone)]
+pub struct Groups {
+	groups: IndexedVec<GroupIndex, Vec<ValidatorIndex>>,
+	by_validator_index: HashMap<ValidatorIndex, GroupIndex>,
+	backing_threshold: u32,
+}
+
+impl Groups {
+	/// Create a new [`Groups`] tracker with the groups and discovery keys
+	/// from the session.
+	pub fn new(
+		groups: IndexedVec<GroupIndex, Vec<ValidatorIndex>>,
+		backing_threshold: u32,
+	) -> Self {
+		let mut by_validator_index = HashMap::new();
+
+		for (i, group) in groups.iter().enumerate() {
+			let index = GroupIndex(i as _);
+			for v in group {
+				by_validator_index.insert(*v, index);
+			}
+		}
+
+		Groups { groups, by_validator_index, backing_threshold }
+	}
+
+	/// Access all the underlying groups.
+	pub fn all(&self) -> &IndexedVec<GroupIndex, Vec<ValidatorIndex>> {
+		&self.groups
+	}
+
+	/// Get the underlying group validators by group index.
+	pub fn get(&self, group_index: GroupIndex) -> Option<&[ValidatorIndex]> {
+		self.groups.get(group_index).map(|x| &x[..])
+	}
+
+	/// Get the backing group size and backing threshold.
+	pub fn get_size_and_backing_threshold(
+		&self,
+		group_index: GroupIndex,
+	) -> Option<(usize, usize)> {
+		self.get(group_index)
+			.map(|g| (g.len(), effective_minimum_backing_votes(g.len(), self.backing_threshold)))
+	}
+
+	/// Get the group index for a validator by index.
+	pub fn by_validator_index(&self, validator_index: ValidatorIndex) -> Option<GroupIndex> {
+		self.by_validator_index.get(&validator_index).map(|x| *x)
+	}
+}