feat: initialize Kurdistan SDK - independent fork of Polkadot SDK

pezkuwi/node/subsystem-util/src/controlled_validator_indices.rs

@@ -0,0 +1,53 @@
+// 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/>.
+
+//! `ControlledValidatorIndices` implementation.
+
+use pezkuwi_primitives::{IndexedVec, SessionIndex, ValidatorId, ValidatorIndex};
+use schnellru::{ByLength, LruMap};
+use sp_keystore::KeystorePtr;
+
+/// Keeps track of the validator indices controlled by the local validator in a given session. For
+/// better performance, the values for each session are cached.
+pub struct ControlledValidatorIndices {
+	/// The indices of the controlled validators, cached by session.
+	controlled_validator_indices: LruMap<SessionIndex, Option<ValidatorIndex>>,
+	keystore: KeystorePtr,
+}
+
+impl ControlledValidatorIndices {
+	/// Create a new instance of `ControlledValidatorIndices`.
+	pub fn new(keystore: KeystorePtr, cache_size: u32) -> Self {
+		let controlled_validator_indices = LruMap::new(ByLength::new(cache_size));
+		Self { controlled_validator_indices, keystore }
+	}
+
+	/// Get the controlled validator indices for a given session. If the indices are not known they
+	/// will be fetched from `session_validators` and cached.
+	pub fn get(
+		&mut self,
+		session: SessionIndex,
+		session_validators: &IndexedVec<ValidatorIndex, ValidatorId>,
+	) -> Option<ValidatorIndex> {
+		self.controlled_validator_indices
+			.get_or_insert(session, || {
+				crate::signing_key_and_index(session_validators.iter(), &self.keystore)
+					.map(|(_, index)| index)
+			})
+			.copied()
+			.expect("We just inserted the controlled indices; qed")
+	}
+}