contracts: Add seal_rent_status

frame/contracts/src/benchmarking/mod.rs

@@ -535,6 +535,32 @@ benchmarks! {
 		let origin = RawOrigin::Signed(instance.caller.clone());
 	}: call(origin, instance.addr, 0u32.into(), Weight::max_value(), vec![])
 
+	seal_rent_status {
+		let r in 0 .. API_BENCHMARK_BATCHES;
+		let pages = code::max_pages::<T>();
+		let code = WasmModule::<T>::from(ModuleDefinition {
+			memory: Some(ImportedMemory::max::<T>()),
+			imported_functions: vec![ImportedFunction {
+				name: "seal_rent_status",
+				params: vec![ValueType::I32, ValueType::I32, ValueType::I32],
+				return_type: None,
+			}],
+			data_segments: vec![DataSegment {
+				offset: 0,
+				value: (pages * 64 * 1024 - 4).to_le_bytes().to_vec(),
+			}],
+			call_body: Some(body::repeated(r * API_BENCHMARK_BATCH_SIZE, &[
+				Instruction::I32Const(1),
+				Instruction::I32Const(4),
+				Instruction::I32Const(0),
+				Instruction::Call(0),
+			])),
+			.. Default::default()
+		});
+		let instance = Contract::<T>::new(code, vec![], Endow::Max)?;
+		let origin = RawOrigin::Signed(instance.caller.clone());
+	}: call(origin, instance.addr, 0u32.into(), Weight::max_value(), vec![])
+
 	seal_weight_to_fee {
 		let r in 0 .. API_BENCHMARK_BATCHES;
 		let pages = code::max_pages::<T>();

frame/contracts/src/exec.rs

@@ -17,7 +17,7 @@
 
 use crate::{
 	CodeHash, Event, Config, Pallet as Contracts,
-	BalanceOf, ContractInfo, gas::GasMeter, rent::Rent, storage::Storage,
+	BalanceOf, ContractInfo, gas::GasMeter, rent::{Rent, RentStatus}, storage::Storage,
 	Error, ContractInfoOf, Schedule, AliveContractInfo, AccountCounter,
 };
 use sp_core::crypto::UncheckedFrom;
@@ -313,6 +313,9 @@ pub trait Ext: sealing::Sealed {
 	/// Information needed for rent calculations.
 	fn rent_params(&self) -> &RentParams<Self::T>;
 
+	/// Information about the required deposit and resulting rent.
+	fn rent_status(&mut self, at_refcount: u32) -> RentStatus<Self::T>;
+
 	/// Get a mutable reference to the nested gas meter.
 	fn gas_meter(&mut self) -> &mut GasMeter<Self::T>;
 
@@ -1240,6 +1243,20 @@ where
 		&self.top_frame().rent_params
 	}
 
+	fn rent_status(&mut self, at_refcount: u32) -> RentStatus<Self::T> {
+		let frame = self.top_frame_mut();
+		let balance = T::Currency::free_balance(&frame.account_id);
+		let code_size = frame.rent_params.code_size;
+		let refcount = frame.rent_params.code_refcount;
+		<Rent<T, E>>::rent_status(
+			&balance,
+			&frame.contract_info(),
+			code_size,
+			refcount,
+			at_refcount,
+		)
+	}
+
 	fn gas_meter(&mut self) -> &mut GasMeter<Self::T> {
 		&mut self.top_frame_mut().nested_meter
 	}
@@ -2194,6 +2211,48 @@ mod tests {
 		});
 	}
 
+	#[test]
+	fn rent_status_works() {
+		let code_hash = MockLoader::insert(Call, |ctx, _| {
+			assert_eq!(ctx.ext.rent_status(0), RentStatus {
+				max_deposit: 80000,
+				current_deposit: 80000,
+				custom_refcount_deposit: None,
+				max_rent: 32,
+				current_rent: 32,
+				custom_refcount_rent: None,
+				_reserved: None,
+			});
+			assert_eq!(ctx.ext.rent_status(1), RentStatus {
+				max_deposit: 80000,
+				current_deposit: 80000,
+				custom_refcount_deposit: Some(80000),
+				max_rent: 32,
+				current_rent: 32,
+				custom_refcount_rent: Some(32),
+				_reserved: None,
+			});
+			exec_success()
+		});
+
+		ExtBuilder::default().build().execute_with(|| {
+			let subsistence = Contracts::<Test>::subsistence_threshold();
+			let schedule = <Test as Config>::Schedule::get();
+			let mut gas_meter = GasMeter::<Test>::new(GAS_LIMIT);
+			set_balance(&ALICE, subsistence * 10);
+			place_contract(&BOB, code_hash);
+			MockStack::run_call(
+				ALICE,
+				BOB,
+				&mut gas_meter,
+				&schedule,
+				0,
+				vec![],
+				None,
+			).unwrap();
+		});
+	}
+
 	#[test]
 	fn in_memory_changes_not_discarded() {
 		// Call stack: BOB -> CHARLIE (trap) -> BOB' (success)