Add Staking precompile delegation amount getter

precompiles/parachain-staking/StakingInterface.sol

@@ -43,6 +43,26 @@ interface ParachainStaking {
     /// @return The total points awarded to all collators in the round
     function points(uint256 round) external view returns (uint256);
 
+    /// @dev The amount delegated in support of the candidate by the delegator
+    /// @custom:selector a73e51bc
+    /// @param delegator Who made this delegation
+    /// @param candidate The candidate for which the delegation is in support of
+    /// @return The amount of the delegation in support of the candidate by the delegator
+    function delegationAmount(address delegator, address candidate)
+        external
+        view
+        returns (uint256);
+
+    /// @dev Whether the delegation is in the top delegations
+    /// @custom:selector 91cc8657
+    /// @param delegator Who made this delegation
+    /// @param candidate The candidate for which the delegation is in support of
+    /// @return If delegation is in top delegations (is counted)
+    function isInTopDelegations(address delegator, address candidate)
+        external
+        view
+        returns (bool);
+
     /// @dev Get the minimum delegation amount
     /// @custom:selector 02985992
     /// @return The minimum delegation amount

precompiles/parachain-staking/src/lib.rs

@@ -196,7 +196,63 @@ where
 		Ok(selected_candidates)
 	}
 
+	#[precompile::public("delegationAmount(address,address)")]
+	#[precompile::view]
+	fn delegation_amount(
+		handle: &mut impl PrecompileHandle,
+		delegator: Address,
+		candidate: Address,
+	) -> EvmResult<U256> {
+		// Fetch info.
+		handle.record_cost(RuntimeHelper::<Runtime>::db_read_gas_cost())?;
+		let (candidate, delegator) = (
+			Runtime::AddressMapping::into_account_id(candidate.0),
+			Runtime::AddressMapping::into_account_id(delegator.0),
+		);
+		let amount = pallet_parachain_staking::Pallet::<Runtime>::delegator_state(&delegator)
+			.and_then(|state| {
+				state
+					.delegations
+					.0
+					.into_iter()
+					.find(|b| b.owner == candidate)
+			})
+			.map_or(
+				U256::zero(),
+				|pallet_parachain_staking::Bond { amount, .. }| amount.into(),
+			);
+
+		Ok(amount)
+	}
+
 	// Role Verifiers
+	#[precompile::public("isInTopDelegations(address,address)")]
+	#[precompile::view]
+	fn is_in_top_delegations(
+		handle: &mut impl PrecompileHandle,
+		delegator: Address,
+		candidate: Address,
+	) -> EvmResult<bool> {
+		let (candidate, delegator) = (
+			Runtime::AddressMapping::into_account_id(candidate.0),
+			Runtime::AddressMapping::into_account_id(delegator.0),
+		);
+
+		// Fetch info.
+		handle.record_cost(RuntimeHelper::<Runtime>::db_read_gas_cost())?;
+		let is_in_top_delegations = pallet_parachain_staking::Pallet::<Runtime>::top_delegations(
+			&candidate,
+		)
+		.map_or(false, |delegations| {
+			delegations
+				.delegations
+				.into_iter()
+				.any(|b| b.owner == delegator)
+		});
+
+		Ok(is_in_top_delegations)
+	}
+
 	#[precompile::public("isDelegator(address)")]
 	#[precompile::public("is_delegator(address)")]
 	#[precompile::view]

precompiles/parachain-staking/src/mock.rs

@@ -155,7 +155,7 @@ parameter_types! {
 	pub const DelegationBondLessDelay: u32 = 2;
 	pub const RewardPaymentDelay: u32 = 2;
 	pub const MinSelectedCandidates: u32 = 5;
-	pub const MaxTopDelegationsPerCandidate: u32 = 4;
+	pub const MaxTopDelegationsPerCandidate: u32 = 2;
 	pub const MaxBottomDelegationsPerCandidate: u32 = 4;
 	pub const MaxDelegationsPerDelegator: u32 = 4;
 	pub const MinCollatorStk: u128 = 10;

precompiles/parachain-staking/src/tests.rs

@@ -49,6 +49,8 @@ fn selectors() {
 	assert!(PCall::is_delegator_selectors().contains(&0xfd8ab482));
 	assert!(PCall::is_candidate_selectors().contains(&0xd51b9e93));
 	assert!(PCall::is_selected_candidate_selectors().contains(&0x740d7d2a));
+	assert!(PCall::delegation_amount_selectors().contains(&0xa73e51bc));
+	assert!(PCall::is_in_top_delegations_selectors().contains(&0x91cc8657));
 	assert!(PCall::points_selectors().contains(&0x9799b4e7));
 	assert!(PCall::min_delegation_selectors().contains(&0x02985992));
 	assert!(PCall::candidate_count_selectors().contains(&0xa9a981a3));
@@ -89,6 +91,8 @@ fn modifiers() {
 		tester.test_view_modifier(PCall::is_candidate_selectors());
 		tester.test_view_modifier(PCall::is_selected_candidate_selectors());
 		tester.test_view_modifier(PCall::points_selectors());
+		tester.test_view_modifier(PCall::delegation_amount_selectors());
+		tester.test_view_modifier(PCall::is_in_top_delegations_selectors());
 		tester.test_view_modifier(PCall::min_delegation_selectors());
 		tester.test_view_modifier(PCall::candidate_count_selectors());
 		tester.test_view_modifier(PCall::round_selectors());
@@ -183,6 +187,126 @@ fn points_non_zero() {
 		});
 }
 
+#[test]
+fn delegation_amount_zero() {
+	ExtBuilder::default()
+		.with_balances(vec![(Alice.into(), 1_000)])
+		.build()
+		.execute_with(|| {
+			precompiles()
+				.prepare_test(
+					Alice,
+					Precompile1,
+					PCall::delegation_amount {
+						delegator: Address(Alice.into()),
+						candidate: Address(Alice.into()),
+					},
+				)
+				.expect_cost(0) // TODO: Test db read/write costs
+				.expect_no_logs()
+				.execute_returns_encoded(0u32);
+		});
+}
+
+#[test]
+fn delegation_amount_nonzero() {
+	ExtBuilder::default()
+		.with_balances(vec![(Alice.into(), 1_000), (Bob.into(), 1_000)])
+		.with_candidates(vec![(Alice.into(), 1_000)])
+		.with_delegations(vec![(Bob.into(), Alice.into(), 1_000)])
+		.build()
+		.execute_with(|| {
+			precompiles()
+				.prepare_test(
+					Alice,
+					Precompile1,
+					PCall::delegation_amount {
+						delegator: Address(Bob.into()),
+						candidate: Address(Alice.into()),
+					},
+				)
+				.expect_cost(0) // TODO: Test db read/write costs
+				.expect_no_logs()
+				.execute_returns_encoded(1000u32);
+		});
+}
+
+#[test]
+fn is_not_in_top_delegations_when_delegation_dne() {
+	ExtBuilder::default()
+		.with_balances(vec![(Alice.into(), 1_000)])
+		.build()
+		.execute_with(|| {
+			precompiles()
+				.prepare_test(
+					Alice,
+					Precompile1,
+					PCall::delegation_amount {
+						delegator: Address(Alice.into()),
+						candidate: Address(Alice.into()),
+					},
+				)
+				.expect_cost(0) // TODO: Test db read/write costs
+				.expect_no_logs()
+				.execute_returns_encoded(false);
+		});
+}
+
+#[test]
+fn is_not_in_top_delegations_because_not_in_top() {
+	ExtBuilder::default()
+		.with_balances(vec![
+			(Alice.into(), 1_000),
+			(Bob.into(), 500),
+			(Charlie.into(), 501),
+			(David.into(), 502),
+		])
+		.with_candidates(vec![(Alice.into(), 1_000)])
+		.with_delegations(vec![
+			(Bob.into(), Alice.into(), 500),
+			(Charlie.into(), Alice.into(), 501),
+			(David.into(), Alice.into(), 502),
+		])
+		.build()
+		.execute_with(|| {
+			precompiles()
+				.prepare_test(
+					Alice,
+					Precompile1,
+					PCall::is_in_top_delegations {
+						delegator: Address(Bob.into()),
+						candidate: Address(Alice.into()),
+					},
+				)
+				.expect_cost(0) // TODO: Test db read/write costs
+				.expect_no_logs()
+				.execute_returns_encoded(false);
+		});
+}
+
+#[test]
+fn is_in_top_delegations() {
+	ExtBuilder::default()
+		.with_balances(vec![(Alice.into(), 1_000), (Bob.into(), 500)])
+		.with_candidates(vec![(Alice.into(), 1_000)])
+		.with_delegations(vec![(Bob.into(), Alice.into(), 500)])
+		.build()
+		.execute_with(|| {
+			precompiles()
+				.prepare_test(
+					Alice,
+					Precompile1,
+					PCall::is_in_top_delegations {
+						delegator: Address(Bob.into()),
+						candidate: Address(Alice.into()),
+					},
+				)
+				.expect_cost(0) // TODO: Test db read/write costs
+				.expect_no_logs()
+				.execute_returns_encoded(true);
+		});
+}
+
 #[test]
 fn round_works() {
 	ExtBuilder::default().build().execute_with(|| {