Statemint Reserve Asset Transfer

polkadot-parachains/parachains-common/src/impls.rs

@@ -16,7 +16,9 @@
 //! Auxillary struct/enums for parachain runtimes.
 //! Taken from polkadot/runtime/common (at a21cd64) and adapted for parachains.
 
-use frame_support::traits::{Currency, Imbalance, OnUnbalanced};
+use frame_support::traits::{fungibles, Contains, Currency, Imbalance, OnUnbalanced};
+use sp_runtime::traits::Zero;
+use sp_std::marker::PhantomData;
 
 pub type NegativeImbalance<T> = <pallet_balances::Pallet<T> as Currency<
 	<T as frame_system::Config>::AccountId,
@@ -60,6 +62,18 @@ where
 	}
 }
 
+/// Allow checking in assets that have issuance > 0.
+pub struct NonZeroIssuance<AccountId, Assets>(PhantomData<(AccountId, Assets)>);
+impl<AccountId, Assets> Contains<<Assets as fungibles::Inspect<AccountId>>::AssetId>
+	for NonZeroIssuance<AccountId, Assets>
+where
+	Assets: fungibles::Inspect<AccountId>,
+{
+	fn contains(id: &<Assets as fungibles::Inspect<AccountId>>::AssetId) -> bool {
+		!Assets::total_issuance(*id).is_zero()
+	}
+}
+
 #[cfg(test)]
 mod tests {
 	use super::*;

polkadot-parachains/parachains-common/src/lib.rs

@@ -51,6 +51,9 @@ mod types {
 
 	// Aura consensus authority.
 	pub type AuraId = sp_consensus_aura::sr25519::AuthorityId;
+
+	// Id used for identifying assets.
+	pub type AssetId = u32;
 }
 
 /// Common constants of parachains.

polkadot-parachains/statemine/src/lib.rs

@@ -31,7 +31,7 @@ use sp_runtime::{
 	create_runtime_str, generic, impl_opaque_keys,
 	traits::{AccountIdLookup, BlakeTwo256, Block as BlockT},
 	transaction_validity::{TransactionSource, TransactionValidity},
-	ApplyExtrinsicResult,
+	ApplyExtrinsicResult, Perbill,
 };
 
 use sp_std::prelude::*;
@@ -56,11 +56,10 @@ use frame_system::{
 };
 pub use parachains_common as common;
 use parachains_common::{
-	impls::DealWithFees, opaque, AccountId, AuraId, Balance, BlockNumber, Hash, Header, Index,
-	Signature, AVERAGE_ON_INITIALIZE_RATIO, HOURS, MAXIMUM_BLOCK_WEIGHT, NORMAL_DISPATCH_RATIO,
-	SLOT_DURATION,
+	impls::{DealWithFees, NonZeroIssuance},
+	opaque, AccountId, AssetId, AuraId, Balance, BlockNumber, Hash, Header, Index, Signature,
+	AVERAGE_ON_INITIALIZE_RATIO, HOURS, MAXIMUM_BLOCK_WEIGHT, NORMAL_DISPATCH_RATIO, SLOT_DURATION,
 };
-use sp_runtime::Perbill;
 
 #[cfg(any(feature = "std", test))]
 pub use sp_runtime::BuildStorage;
@@ -71,13 +70,14 @@ use polkadot_parachain::primitives::Sibling;
 use polkadot_runtime_common::{BlockHashCount, RocksDbWeight, SlowAdjustingFeeUpdate};
 use xcm::latest::prelude::*;
 use xcm_builder::{
-	AccountId32Aliases, AllowTopLevelPaidExecutionFrom, AllowUnpaidExecutionFrom, CurrencyAdapter,
-	EnsureXcmOrigin, FixedWeightBounds, IsConcrete, LocationInverter, NativeAsset,
+	AccountId32Aliases, AllowTopLevelPaidExecutionFrom, AllowUnpaidExecutionFrom,
+	AsPrefixedGeneralIndex, ConvertedConcreteAssetId, CurrencyAdapter, EnsureXcmOrigin,
+	FixedWeightBounds, FungiblesAdapter, IsConcrete, LocationInverter, NativeAsset,
 	ParentAsSuperuser, ParentIsDefault, RelayChainAsNative, SiblingParachainAsNative,
 	SiblingParachainConvertsVia, SignedAccountId32AsNative, SignedToAccountId32,
 	SovereignSignedViaLocation, TakeWeightCredit, UsingComponents,
 };
-use xcm_executor::{Config, XcmExecutor};
+use xcm_executor::{traits::JustTry, Config, XcmExecutor};
 
 impl_opaque_keys! {
 	pub struct SessionKeys {
@@ -241,7 +241,7 @@ pub type AssetsForceOrigin = EnsureOneOf<
 impl pallet_assets::Config for Runtime {
 	type Event = Event;
 	type Balance = Balance;
-	type AssetId = u32;
+	type AssetId = AssetId;
 	type Currency = Balances;
 	type ForceOrigin = AssetsForceOrigin;
 	type AssetDeposit = AssetDeposit;
@@ -457,6 +457,8 @@ parameter_types! {
 	pub const RelayNetwork: NetworkId = NetworkId::Kusama;
 	pub RelayChainOrigin: Origin = cumulus_pallet_xcm::Origin::Relay.into();
 	pub Ancestry: MultiLocation = Parachain(ParachainInfo::parachain_id().into()).into();
+	pub const Local: MultiLocation = Here.into();
+	pub CheckingAccount: AccountId = PolkadotXcm::check_account();
 }
 
 /// Type for specifying how a `MultiLocation` can be converted into an `AccountId`. This is used
@@ -471,20 +473,44 @@ pub type LocationToAccountId = (
 	AccountId32Aliases<RelayNetwork, AccountId>,
 );
 
-/// Means for transacting assets on this chain.
-pub type LocalAssetTransactor = CurrencyAdapter<
+/// Means for transacting the native currency on this chain.
+pub type CurrencyTransactor = CurrencyAdapter<
 	// Use this currency:
 	Balances,
 	// Use this currency when it is a fungible asset matching the given location or name:
 	IsConcrete<KsmLocation>,
-	// Do a simple punn to convert an AccountId32 MultiLocation into a native chain account ID:
+	// Convert an XCM MultiLocation into a local account id:
 	LocationToAccountId,
 	// Our chain's account ID type (we can't get away without mentioning it explicitly):
 	AccountId,
-	// We don't track any teleports.
+	// We don't track any teleports of `Balances`.
 	(),
 >;
 
+/// Means for transacting assets besides the native currency on this chain.
+pub type FungiblesTransactor = FungiblesAdapter<
+	// Use this fungibles implementation:
+	Assets,
+	// Use this currency when it is a fungible asset matching the given location or name:
+	ConvertedConcreteAssetId<
+		AssetId,
+		Balance,
+		AsPrefixedGeneralIndex<Local, AssetId, JustTry>,
+		JustTry,
+	>,
+	// Convert an XCM MultiLocation into a local account id:
+	LocationToAccountId,
+	// Our chain's account ID type (we can't get away without mentioning it explicitly):
+	AccountId,
+	// We only want to allow teleports of known assets. We use non-zero issuance as an indication
+	// that this asset is known.
+	NonZeroIssuance<AccountId, Assets>,
+	// The account to use for tracking teleports.
+	CheckingAccount,
+>;
+/// Means for transacting assets on this chain.
+pub type AssetTransactors = (CurrencyTransactor, FungiblesTransactor);
+
 /// This is the type we use to convert an (incoming) XCM origin into a local `Origin` instance,
 /// ready for dispatching a transaction with Xcm's `Transact`. There is an `OriginKind` which can
 /// biases the kind of local `Origin` it will become.
@@ -534,7 +560,7 @@ impl Config for XcmConfig {
 	type Call = Call;
 	type XcmSender = XcmRouter;
 	// How to withdraw and deposit an asset.
-	type AssetTransactor = LocalAssetTransactor;
+	type AssetTransactor = AssetTransactors;
 	type OriginConverter = XcmOriginToTransactDispatchOrigin;
 	type IsReserve = NativeAsset;
 	type IsTeleporter = NativeAsset; // <- should be enough to allow teleportation of KSM

polkadot-parachains/statemint/src/lib.rs

@@ -31,7 +31,7 @@ use sp_runtime::{
 	create_runtime_str, generic, impl_opaque_keys,
 	traits::{AccountIdLookup, BlakeTwo256, Block as BlockT},
 	transaction_validity::{TransactionSource, TransactionValidity},
-	ApplyExtrinsicResult,
+	ApplyExtrinsicResult, Perbill,
 };
 
 use sp_std::prelude::*;
@@ -56,11 +56,10 @@ use frame_system::{
 };
 pub use parachains_common as common;
 use parachains_common::{
-	impls::DealWithFees, opaque, AccountId, AuraId, Balance, BlockNumber, Hash, Header, Index,
-	Signature, AVERAGE_ON_INITIALIZE_RATIO, HOURS, MAXIMUM_BLOCK_WEIGHT, NORMAL_DISPATCH_RATIO,
-	SLOT_DURATION,
+	impls::{DealWithFees, NonZeroIssuance},
+	opaque, AccountId, AssetId, AuraId, Balance, BlockNumber, Hash, Header, Index, Signature,
+	AVERAGE_ON_INITIALIZE_RATIO, HOURS, MAXIMUM_BLOCK_WEIGHT, NORMAL_DISPATCH_RATIO, SLOT_DURATION,
 };
-use sp_runtime::Perbill;
 
 #[cfg(any(feature = "std", test))]
 pub use sp_runtime::BuildStorage;
@@ -71,13 +70,14 @@ use polkadot_parachain::primitives::Sibling;
 use polkadot_runtime_common::{BlockHashCount, RocksDbWeight, SlowAdjustingFeeUpdate};
 use xcm::latest::prelude::*;
 use xcm_builder::{
-	AccountId32Aliases, AllowTopLevelPaidExecutionFrom, AllowUnpaidExecutionFrom, CurrencyAdapter,
-	EnsureXcmOrigin, FixedWeightBounds, IsConcrete, LocationInverter, NativeAsset,
+	AccountId32Aliases, AllowTopLevelPaidExecutionFrom, AllowUnpaidExecutionFrom,
+	AsPrefixedGeneralIndex, ConvertedConcreteAssetId, CurrencyAdapter, EnsureXcmOrigin,
+	FixedWeightBounds, FungiblesAdapter, IsConcrete, LocationInverter, NativeAsset,
 	ParentAsSuperuser, ParentIsDefault, RelayChainAsNative, SiblingParachainAsNative,
 	SiblingParachainConvertsVia, SignedAccountId32AsNative, SignedToAccountId32,
 	SovereignSignedViaLocation, TakeWeightCredit, UsingComponents,
 };
-use xcm_executor::{Config, XcmExecutor};
+use xcm_executor::{traits::JustTry, Config, XcmExecutor};
 
 impl_opaque_keys! {
 	pub struct SessionKeys {
@@ -236,7 +236,7 @@ pub type AssetsForceOrigin = EnsureOneOf<
 impl pallet_assets::Config for Runtime {
 	type Event = Event;
 	type Balance = Balance;
-	type AssetId = u32;
+	type AssetId = AssetId;
 	type Currency = Balances;
 	type ForceOrigin = AssetsForceOrigin;
 	type AssetDeposit = AssetDeposit;
@@ -422,6 +422,8 @@ parameter_types! {
 	pub const RelayNetwork: NetworkId = NetworkId::Polkadot;
 	pub RelayChainOrigin: Origin = cumulus_pallet_xcm::Origin::Relay.into();
 	pub Ancestry: MultiLocation = Parachain(ParachainInfo::parachain_id().into()).into();
+	pub const Local: MultiLocation = Here.into();
+	pub CheckingAccount: AccountId = PolkadotXcm::check_account();
 }
 
 /// Type for specifying how a `MultiLocation` can be converted into an `AccountId`. This is used
@@ -436,20 +438,44 @@ pub type LocationToAccountId = (
 	AccountId32Aliases<RelayNetwork, AccountId>,
 );
 
-/// Means for transacting assets on this chain.
-pub type LocalAssetTransactor = CurrencyAdapter<
+/// Means for transacting the native currency on this chain.
+pub type CurrencyTransactor = CurrencyAdapter<
 	// Use this currency:
 	Balances,
 	// Use this currency when it is a fungible asset matching the given location or name:
 	IsConcrete<DotLocation>,
-	// Do a simple punn to convert an AccountId32 MultiLocation into a native chain account ID:
+	// Convert an XCM MultiLocation into a local account id:
 	LocationToAccountId,
 	// Our chain's account ID type (we can't get away without mentioning it explicitly):
 	AccountId,
-	// We don't track any teleports.
+	// We don't track any teleports of `Balances`.
 	(),
 >;
 
+/// Means for transacting assets besides the native currency on this chain.
+pub type FungiblesTransactor = FungiblesAdapter<
+	// Use this fungibles implementation:
+	Assets,
+	// Use this currency when it is a fungible asset matching the given location or name:
+	ConvertedConcreteAssetId<
+		AssetId,
+		Balance,
+		AsPrefixedGeneralIndex<Local, AssetId, JustTry>,
+		JustTry,
+	>,
+	// Convert an XCM MultiLocation into a local account id:
+	LocationToAccountId,
+	// Our chain's account ID type (we can't get away without mentioning it explicitly):
+	AccountId,
+	// We only want to allow teleports of known assets. We use non-zero issuance as an indication
+	// that this asset is known.
+	NonZeroIssuance<AccountId, Assets>,
+	// The account to use for tracking teleports.
+	CheckingAccount,
+>;
+/// Means for transacting assets on this chain.
+pub type AssetTransactors = (CurrencyTransactor, FungiblesTransactor);
+
 /// This is the type we use to convert an (incoming) XCM origin into a local `Origin` instance,
 /// ready for dispatching a transaction with Xcm's `Transact`. There is an `OriginKind` which can
 /// biases the kind of local `Origin` it will become.
@@ -498,8 +524,7 @@ pub struct XcmConfig;
 impl Config for XcmConfig {
 	type Call = Call;
 	type XcmSender = XcmRouter;
-	// How to withdraw and deposit an asset.
-	type AssetTransactor = LocalAssetTransactor;
+	type AssetTransactor = AssetTransactors;
 	type OriginConverter = XcmOriginToTransactDispatchOrigin;
 	type IsReserve = NativeAsset;
 	type IsTeleporter = NativeAsset; // <- should be enough to allow teleportation of DOT