pezkuwi-subxt/parachains/common/src/xcm_config.rs

use crate::impls::AccountIdOf;
use core::{marker::PhantomData, ops::ControlFlow};
use frame_support::{
	log,
	traits::{
		fungibles::Inspect, tokens::ConversionToAssetBalance, ContainsPair, ProcessMessageError,
	},
	weights::Weight,
};
use sp_runtime::traits::Get;
use xcm::latest::prelude::*;
use xcm_builder::{CreateMatcher, MatchXcm};
use xcm_executor::traits::ShouldExecute;

//TODO: move DenyThenTry to polkadot's xcm module.
/// Deny executing the XCM if it matches any of the Deny filter regardless of anything else.
/// If it passes the Deny, and matches one of the Allow cases then it is let through.
pub struct DenyThenTry<Deny, Allow>(PhantomData<Deny>, PhantomData<Allow>)
where
	Deny: ShouldExecute,
	Allow: ShouldExecute;

impl<Deny, Allow> ShouldExecute for DenyThenTry<Deny, Allow>
where
	Deny: ShouldExecute,
	Allow: ShouldExecute,
{
	fn should_execute<RuntimeCall>(
		origin: &MultiLocation,
		message: &mut [Instruction<RuntimeCall>],
		max_weight: Weight,
		weight_credit: &mut Weight,
	) -> Result<(), ProcessMessageError> {
		Deny::should_execute(origin, message, max_weight, weight_credit)?;
		Allow::should_execute(origin, message, max_weight, weight_credit)
	}
}

// See issue <https://github.com/paritytech/polkadot/issues/5233>
pub struct DenyReserveTransferToRelayChain;
impl ShouldExecute for DenyReserveTransferToRelayChain {
	fn should_execute<RuntimeCall>(
		origin: &MultiLocation,
		message: &mut [Instruction<RuntimeCall>],
		_max_weight: Weight,
		_weight_credit: &mut Weight,
	) -> Result<(), ProcessMessageError> {
		message.matcher().match_next_inst_while(
			|_| true,
			|inst| match inst {
				InitiateReserveWithdraw {
					reserve: MultiLocation { parents: 1, interior: Here },
					..
				} |
				DepositReserveAsset {
					dest: MultiLocation { parents: 1, interior: Here }, ..
				} |
				TransferReserveAsset {
					dest: MultiLocation { parents: 1, interior: Here }, ..
				} => {
					Err(ProcessMessageError::Unsupported) // Deny
				},

				// An unexpected reserve transfer has arrived from the Relay Chain. Generally,
				// `IsReserve` should not allow this, but we just log it here.
				ReserveAssetDeposited { .. }
					if matches!(origin, MultiLocation { parents: 1, interior: Here }) =>
				{
					log::warn!(
						target: "xcm::barrier",
						"Unexpected ReserveAssetDeposited from the Relay Chain",
					);
					Ok(ControlFlow::Continue(()))
				},

				_ => Ok(ControlFlow::Continue(())),
			},
		)?;

		// Permit everything else
		Ok(())
	}
}

/// A `ChargeFeeInFungibles` implementation that converts the output of
/// a given WeightToFee implementation an amount charged in
/// a particular assetId from pallet-assets
pub struct AssetFeeAsExistentialDepositMultiplier<
	Runtime,
	WeightToFee,
	BalanceConverter,
	AssetInstance: 'static,
>(PhantomData<(Runtime, WeightToFee, BalanceConverter, AssetInstance)>);
impl<CurrencyBalance, Runtime, WeightToFee, BalanceConverter, AssetInstance>
	cumulus_primitives_utility::ChargeWeightInFungibles<
		AccountIdOf<Runtime>,
		pallet_assets::Pallet<Runtime, AssetInstance>,
	> for AssetFeeAsExistentialDepositMultiplier<Runtime, WeightToFee, BalanceConverter, AssetInstance>
where
	Runtime: pallet_assets::Config<AssetInstance>,
	WeightToFee: frame_support::weights::WeightToFee<Balance = CurrencyBalance>,
	BalanceConverter: ConversionToAssetBalance<
		CurrencyBalance,
		<Runtime as pallet_assets::Config<AssetInstance>>::AssetId,
		<Runtime as pallet_assets::Config<AssetInstance>>::Balance,
	>,
	AccountIdOf<Runtime>:
		From<polkadot_primitives::AccountId> + Into<polkadot_primitives::AccountId>,
{
	fn charge_weight_in_fungibles(
		asset_id: <pallet_assets::Pallet<Runtime, AssetInstance> as Inspect<
			AccountIdOf<Runtime>,
		>>::AssetId,
		weight: Weight,
	) -> Result<
		<pallet_assets::Pallet<Runtime, AssetInstance> as Inspect<AccountIdOf<Runtime>>>::Balance,
		XcmError,
	> {
		let amount = WeightToFee::weight_to_fee(&weight);
		// If the amount gotten is not at least the ED, then make it be the ED of the asset
		// This is to avoid burning assets and decreasing the supply
		let asset_amount = BalanceConverter::to_asset_balance(amount, asset_id)
			.map_err(|_| XcmError::TooExpensive)?;
		Ok(asset_amount)
	}
}

/// Accepts an asset if it is a native asset from a particular `MultiLocation`.
pub struct ConcreteNativeAssetFrom<Location>(PhantomData<Location>);
impl<Location: Get<MultiLocation>> ContainsPair<MultiAsset, MultiLocation>
	for ConcreteNativeAssetFrom<Location>
{
	fn contains(asset: &MultiAsset, origin: &MultiLocation) -> bool {
		log::trace!(target: "xcm::filter_asset_location",
			"ConcreteNativeAsset asset: {:?}, origin: {:?}, location: {:?}",
			asset, origin, Location::get());
		matches!(asset.id, Concrete(ref id) if id == origin && origin == &Location::get())
	}
}