Cleanup and improvements for ControlledValidatorIndices (#8896)

Improvements for `ControlledValidatorIndices` from
#8837:
      - remove unneeded dependency
- more readable implementations for `get` and
`find_controlled_validator_indices`

Author: tdimitrov

Cargo.lock

@@ -104,7 +104,9 @@ impl<'a> CandidateEnvironment<'a> {
 			d
 		};
 
-		let controlled_indices = controlled_indices.get(session_index, &session.validators).clone();
+		let controlled_indices = controlled_indices
+			.get(session_index, &session.validators)
+			.map_or(HashSet::new(), |index| HashSet::from([index]));
 
 		Some(Self { session_index, session, executor_params, controlled_indices, disabled_indices })
 	}

polkadot/node/core/dispute-coordinator/src/import.rs

@@ -32,7 +32,6 @@ polkadot-node-subsystem-types = { workspace = true, default-features = true }
 polkadot-overseer = { workspace = true, default-features = true }
 polkadot-primitives = { workspace = true, default-features = true }
 
-sc-keystore = { workspace = true, default-features = true }
 sp-application-crypto = { workspace = true, default-features = true }
 sp-core = { workspace = true, default-features = true }
 sp-keystore = { workspace = true, default-features = true }

polkadot/node/subsystem-util/Cargo.toml

@@ -16,24 +16,21 @@
 
 //! `ControlledValidatorIndices` implementation.
 
-use polkadot_primitives::{IndexedVec, SessionIndex, ValidatorId, ValidatorIndex, ValidatorPair};
-use sc_keystore::LocalKeystore;
+use polkadot_primitives::{IndexedVec, SessionIndex, ValidatorId, ValidatorIndex};
 use schnellru::{ByLength, LruMap};
-use sp_application_crypto::{AppCrypto, ByteArray};
-use sp_keystore::Keystore;
-use std::{collections::HashSet, sync::Arc};
+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, HashSet<ValidatorIndex>>,
-	keystore: Arc<LocalKeystore>,
+	controlled_validator_indices: LruMap<SessionIndex, Option<ValidatorIndex>>,
+	keystore: KeystorePtr,
 }
 
 impl ControlledValidatorIndices {
 	/// Create a new instance of `ControlledValidatorIndices`.
-	pub fn new(keystore: Arc<LocalKeystore>, cache_size: u32) -> Self {
+	pub fn new(keystore: KeystorePtr, cache_size: u32) -> Self {
 		let controlled_validator_indices = LruMap::new(ByLength::new(cache_size));
 		Self { controlled_validator_indices, keystore }
 	}
@@ -44,34 +41,13 @@ impl ControlledValidatorIndices {
 		&mut self,
 		session: SessionIndex,
 		session_validators: &IndexedVec<ValidatorIndex, ValidatorId>,
-	) -> &HashSet<ValidatorIndex> {
-		if self.controlled_validator_indices.get(&session).is_none() {
-			let indices =
-				Self::find_controlled_validator_indices(&self.keystore, session_validators);
-			self.controlled_validator_indices.insert(session, indices.clone());
-		}
-
+	) -> Option<ValidatorIndex> {
 		self.controlled_validator_indices
-			.get(&session)
+			.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")
 	}
-
-	/// Find indices controlled by this validator.
-	///
-	/// That is all `ValidatorIndex`es we have private keys for. Usually this will only be one.
-	fn find_controlled_validator_indices(
-		keystore: &LocalKeystore,
-		validators: &IndexedVec<ValidatorIndex, ValidatorId>,
-	) -> HashSet<ValidatorIndex> {
-		let mut controlled = HashSet::new();
-		for (index, validator) in validators.iter().enumerate() {
-			if !Keystore::has_keys(keystore, &[(validator.to_raw_vec(), ValidatorPair::ID)]) {
-				continue
-			}
-
-			controlled.insert(ValidatorIndex(index as _));
-		}
-
-		controlled
-	}
 }

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

@@ -0,0 +1,13 @@
+title: Improvements for `ControlledValidatorIndices`
+doc:
+  - audience: Node Dev
+    description: |
+      Improvements for `ControlledValidatorIndices`:
+      - remove unneeded dependency
+      - more readable implementations for `get` and `find_controlled_validator_indices`
+
+crates:
+- name: polkadot-node-subsystem-util
+  bump: patch
+- name: polkadot-node-core-dispute-coordinator
+  bump: patch