Refactor WeightToFee to include ProofSize (#215)

* Removed FixedRateOfFungibles

* fmt

* added comments

* fmt

* removed unused imports

* fmt

* removed allow unpaid execution from rockmine following PR #211

* Include new traders from PR #221

* minor fixes

* minor fixes

* fmt

Cargo.toml

@@ -99,6 +99,7 @@ sc-transaction-pool-api = { git = "https://github.com/paritytech/substrate", bra
 # Substrate Runtime
 sp-runtime = { git = "https://github.com/paritytech/substrate", branch = "polkadot-v0.9.40", default-features = false }
 sp-inherents = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.40" }
+sp-arithmetic = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.40" }
 sp-std = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.40" }
 sp-version = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "polkadot-v0.9.40" }
 

runtime/stout/src/xcm_config.rs

@@ -15,7 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use crate::{constants::fee::default_fee_per_second, AllPalletsWithSystem};
+use crate::AllPalletsWithSystem;
 
 use super::{
 	AccountId, Assets, Balance, Balances, ParachainInfo, ParachainSystem, PolkadotXcm, Runtime,
@@ -45,9 +45,9 @@ use xcm::latest::{prelude::*, Fungibility::Fungible, MultiAsset, MultiLocation};
 use xcm_builder::{
 	AccountId32Aliases, AllowKnownQueryResponses, AllowSubscriptionsFrom,
 	AllowTopLevelPaidExecutionFrom, AllowUnpaidExecutionFrom, AsPrefixedGeneralIndex,
-	ConvertedConcreteId, CurrencyAdapter, EnsureXcmOrigin, FixedRateOfFungible, FixedWeightBounds,
-	FungiblesAdapter, IsConcrete, MintLocation, NativeAsset, NoChecking, ParentAsSuperuser,
-	ParentIsPreset, RelayChainAsNative, SiblingParachainAsNative, SiblingParachainConvertsVia,
+	ConvertedConcreteId, CurrencyAdapter, EnsureXcmOrigin, FixedWeightBounds, FungiblesAdapter,
+	IsConcrete, MintLocation, NativeAsset, NoChecking, ParentAsSuperuser, ParentIsPreset,
+	RelayChainAsNative, SiblingParachainAsNative, SiblingParachainConvertsVia,
 	SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation, TakeWeightCredit,
 	UsingComponents,
 };
@@ -194,11 +194,6 @@ parameter_types! {
 	// Statemine's Assets pallet index
 	pub StatemineAssetsPalletLocation: MultiLocation =
 		MultiLocation::new(1, X2(Parachain(1000), PalletInstance(50)));
-	pub XUsdPerSecond: (AssetId, u128, u128) = (
-		MultiLocation::new(1, X3(Parachain(1000), PalletInstance(50), GeneralIndex(1))).into(),
-		default_fee_per_second() * 10,
-		0
-	);
 }
 
 //- From PR https://github.com/paritytech/cumulus/pull/936
@@ -240,10 +235,8 @@ impl xcm_executor::Config for XcmConfig {
 	type IsTeleporter = (); // Teleporting is disabled.
 	type Barrier = Barrier;
 	type Weigher = FixedWeightBounds<UnitWeightCost, RuntimeCall, MaxInstructions>;
-	type Trader = (
-		FixedRateOfFungible<XUsdPerSecond, ()>,
-		UsingComponents<WeightToFee, SelfReserve, AccountId, Balances, DealWithFees<Runtime>>,
-	);
+	type Trader =
+		UsingComponents<WeightToFee, SelfReserve, AccountId, Balances, DealWithFees<Runtime>>;
 	type ResponseHandler = PolkadotXcm;
 	type AssetTrap = PolkadotXcm;
 	type AssetClaims = PolkadotXcm;

runtime/trappist/Cargo.toml

@@ -24,6 +24,7 @@ smallvec = { workspace = true }
 # Substrate Dependencies
 ## Substrate Primitive Dependencies
 sp-api = { workspace = true }
+sp-arithmetic = { workspace = true }
 sp-block-builder = { workspace = true }
 sp-consensus-aura = { workspace = true }
 sp-core = { workspace = true }

runtime/trappist/src/constants.rs

@@ -37,20 +37,21 @@ pub mod currency {
 pub mod fee {
 	use frame_support::weights::{
 		constants::{ExtrinsicBaseWeight, WEIGHT_REF_TIME_PER_SECOND},
-		WeightToFeeCoefficient, WeightToFeeCoefficients, WeightToFeePolynomial,
+		Weight, WeightToFeeCoefficient, WeightToFeeCoefficients, WeightToFeePolynomial,
 	};
 	use polkadot_core_primitives::Balance;
 	use smallvec::smallvec;
+
 	pub use sp_runtime::Perbill;
+	use sp_runtime::SaturatedConversion;
+
+	use crate::impls::WeightCoefficientCalc;
 
 	use super::currency::CENTS;
 
 	/// The block saturation level. Fees will be updates based on this value.
 	pub const TARGET_BLOCK_FULLNESS: Perbill = Perbill::from_percent(25);
 
-	//TODO: Update WeightToFee functionality to match cummulus implementation (Should be done in a
-	// separated issue)
-
 	/// Handles converting a weight scalar to a fee value, based on the scale and granularity of the
 	/// node's balance type.
 	///
@@ -61,13 +62,43 @@ pub mod fee {
 	/// Yet, it can be used for any other sort of change to weight-fee. Some examples being:
 	///   - Setting it to `0` will essentially disable the weight fee.
 	///   - Setting it to `1` will cause the literal `#[weight = x]` values to be charged.
+	///
+	/// TODO: Once the runtime is upgraded to polkadot v0.9.42 or above refactor this using
+	/// the FeePolynomial struct that already includes the methods to make this calculations
+	/// and remove the custom WeightCoefficientCalc inside ./trappist/src/impls.rs
 	pub struct WeightToFee;
-	impl WeightToFeePolynomial for WeightToFee {
+	impl frame_support::weights::WeightToFee for WeightToFee {
+		type Balance = Balance;
+
+		fn weight_to_fee(weight: &Weight) -> Self::Balance {
+			let ref_time = Balance::saturated_from(weight.ref_time());
+			let proof_size = Balance::saturated_from(weight.proof_size());
+
+			let ref_polynomial = RefTimeToFee::polynomial();
+			let proof_polynomial = ProofSizeToFee::polynomial();
+
+			// Get fee amount from ref_time based on the RefTime polynomial
+			let ref_fee: Balance =
+				ref_polynomial.iter().fold(0, |acc, term| term.saturating_eval(acc, ref_time));
+
+			// Get fee amount from proof_size based on the ProofSize polynomial
+			let proof_fee: Balance = proof_polynomial
+				.iter()
+				.fold(0, |acc, term| term.saturating_eval(acc, proof_size));
+
+			// Take the maximum instead of the sum to charge by the more scarce resource.
+			ref_fee.max(proof_fee)
+		}
+	}
+
+	/// Maps the Ref time component of `Weight` to a fee.
+	pub struct RefTimeToFee;
+	impl WeightToFeePolynomial for RefTimeToFee {
 		type Balance = Balance;
 		fn polynomial() -> WeightToFeeCoefficients<Self::Balance> {
 			// in Kusama, extrinsic base weight (smallest non-zero weight) is mapped to 1/10 CENT:
 			// in Statemine, we map to 1/10 of that, or 1/100 CENT
-			let p = super::currency::CENTS;
+			let p = CENTS;
 			let q = 100 * Balance::from(ExtrinsicBaseWeight::get().ref_time());
 			smallvec![WeightToFeeCoefficient {
 				degree: 1,
@@ -78,6 +109,24 @@ pub mod fee {
 		}
 	}
 
+	/// Maps the proof size component of `Weight` to a fee.
+	pub struct ProofSizeToFee;
+	impl WeightToFeePolynomial for ProofSizeToFee {
+		type Balance = Balance;
+		fn polynomial() -> WeightToFeeCoefficients<Self::Balance> {
+			// Map 10kb proof to 1 CENT.
+			let p = CENTS;
+			let q = 10_000;
+
+			smallvec![WeightToFeeCoefficient {
+				degree: 1,
+				negative: false,
+				coeff_frac: Perbill::from_rational(p % q, q),
+				coeff_integer: p / q,
+			}]
+		}
+	}
+
 	pub fn base_tx_fee() -> Balance {
 		CENTS / 10
 	}

runtime/trappist/src/impls.rs

@@ -22,10 +22,11 @@ use super::*;
 use cumulus_primitives_core::{relay_chain::BlockNumber as RelayBlockNumber, DmpMessageHandler};
 use frame_support::{
 	traits::{Contains, Currency, Imbalance, OnUnbalanced},
-	weights::Weight,
+	weights::{Weight, WeightToFeeCoefficient},
 };
 pub use log;
-use sp_runtime::DispatchResult;
+use sp_arithmetic::traits::{BaseArithmetic, Unsigned};
+use sp_runtime::{DispatchResult, SaturatedConversion};
 
 use sp_std::marker::PhantomData;
 
@@ -112,6 +113,34 @@ impl xcm_primitives::PauseXcmExecution for XcmExecutionManager {
 		XcmpQueue::resume_xcm_execution(RuntimeOrigin::root())
 	}
 }
+
+pub trait WeightCoefficientCalc<Balance> {
+	fn saturating_eval(&self, result: Balance, x: Balance) -> Balance;
+}
+
+impl<Balance> WeightCoefficientCalc<Balance> for WeightToFeeCoefficient<Balance>
+where
+	Balance: BaseArithmetic + From<u32> + Copy + Unsigned + SaturatedConversion,
+{
+	fn saturating_eval(&self, mut result: Balance, x: Balance) -> Balance {
+		let power = x.saturating_pow(self.degree.into());
+
+		let frac = self.coeff_frac * power; // Overflow safe since coeff_frac is strictly less than 1.
+		let integer = self.coeff_integer.saturating_mul(power);
+		// Do not add them together here to avoid an underflow.
+
+		if self.negative {
+			result = result.saturating_sub(frac);
+			result = result.saturating_sub(integer);
+		} else {
+			result = result.saturating_add(frac);
+			result = result.saturating_add(integer);
+		}
+
+		result
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;

runtime/trappist/src/xcm_config.rs

@@ -16,13 +16,15 @@
 // limitations under the License.
 
 use crate::{
-	constants::fee::default_fee_per_second, impls::ToAuthor, weights::TrappistDropAssetsWeigher,
+	constants::fee::{default_fee_per_second, WeightToFee},
+	impls::ToAuthor,
+	weights::TrappistDropAssetsWeigher,
 	AllPalletsWithSystem,
 };
 
 use super::{
 	AccountId, AssetRegistry, Assets, Balance, Balances, ParachainInfo, ParachainSystem,
-	PolkadotXcm, Runtime, RuntimeCall, RuntimeEvent, RuntimeOrigin, WeightToFee, XcmpQueue,
+	PolkadotXcm, Runtime, RuntimeCall, RuntimeEvent, RuntimeOrigin, XcmpQueue,
 };
 use frame_support::{
 	match_types, parameter_types,
@@ -47,12 +49,11 @@ use xcm::latest::{prelude::*, Fungibility::Fungible, MultiAsset, MultiLocation};
 
 use xcm_builder::{
 	AccountId32Aliases, AllowKnownQueryResponses, AllowSubscriptionsFrom,
-	AllowTopLevelPaidExecutionFrom, AllowUnpaidExecutionFrom, AsPrefixedGeneralIndex,
-	ConvertedConcreteId, CurrencyAdapter, EnsureXcmOrigin, FixedRateOfFungible, FixedWeightBounds,
-	FungiblesAdapter, IsConcrete, MintLocation, NativeAsset, NoChecking, ParentAsSuperuser,
-	ParentIsPreset, RelayChainAsNative, SiblingParachainAsNative, SiblingParachainConvertsVia,
-	SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation, TakeWeightCredit,
-	UsingComponents, WeightInfoBounds,
+	AllowTopLevelPaidExecutionFrom, AllowUnpaidExecutionFrom, CurrencyAdapter, EnsureXcmOrigin,
+	FixedRateOfFungible, FungiblesAdapter, IsConcrete, MintLocation, NativeAsset, NoChecking,
+	ParentAsSuperuser, ParentIsPreset, RelayChainAsNative, SiblingParachainAsNative,
+	SiblingParachainConvertsVia, SignedAccountId32AsNative, SignedToAccountId32,
+	SovereignSignedViaLocation, TakeWeightCredit, UsingComponents, WeightInfoBounds,
 };
 use xcm_executor::XcmExecutor;
 
@@ -208,7 +209,6 @@ pub type Barrier = DenyThenTry<
 		AllowTopLevelPaidExecutionFrom<Everything>,
 		// Parent and its exec plurality get free execution
 		AllowUnpaidExecutionFrom<ParentOrParentsExecutivePlurality>,
-		AllowUnpaidExecutionFrom<Rockmine>,
 		// Expected responses are OK.
 		AllowKnownQueryResponses<PolkadotXcm>,
 		// Subscriptions for version tracking are OK.
@@ -222,11 +222,13 @@ parameter_types! {
 	// Rockmine's Assets pallet index
 	pub RockmineAssetsPalletLocation: MultiLocation =
 		MultiLocation::new(1, X2(Parachain(1000), PalletInstance(50)));
-	pub XUsdPerSecond: (xcm::v3::AssetId, u128, u128) = (
-		MultiLocation::new(1, X3(Parachain(1000), PalletInstance(50), GeneralIndex(1))).into(),
+	pub RUsdPerSecond: (xcm::v3::AssetId, u128, u128) = (
+		MultiLocation::new(1, X3(Parachain(1000), PalletInstance(50), GeneralIndex(1984))).into(),
 		default_fee_per_second() * 10,
-		0
+		0u128
 	);
+	/// Roc = 7 RUSD
+	pub RocPerSecond: (xcm::v3::AssetId, u128,u128) = (MultiLocation::parent().into(), default_fee_per_second() * 70, 0u128);
 }
 
 //- From PR https://github.com/paritytech/cumulus/pull/936
@@ -253,7 +255,14 @@ impl<T: Get<MultiLocation>> ContainsPair<MultiAsset, MultiLocation> for ReserveA
 	}
 }
 
-//--
+pub type Traders = (
+	// RUSD
+	FixedRateOfFungible<RUsdPerSecond, ()>,
+	// Roc
+	FixedRateOfFungible<RocPerSecond, ()>,
+	// Everything else
+	UsingComponents<WeightToFee, SelfReserve, AccountId, Balances, ToAuthor<Runtime>>,
+);
 
 pub type Reserves = (NativeAsset, ReserveAssetsFrom<RockmineLocation>);
 
@@ -271,11 +280,7 @@ impl xcm_executor::Config for XcmConfig {
 		RuntimeCall,
 		MaxInstructions,
 	>;
-	//TODO: Modify current config of Trader removing XUsdPerSecond Implementation
-	type Trader = (
-		FixedRateOfFungible<XUsdPerSecond, ()>,
-		UsingComponents<WeightToFee, SelfReserve, AccountId, Balances, ToAuthor<Runtime>>,
-	);
+	type Trader = Traders;
 	type ResponseHandler = PolkadotXcm;
 	type AssetTrap = TrappistDropAssets<
 		AssetIdForTrustBackedAssets,