diff --git a/polkadot/xcm/xcm-builder/src/currency_adapter.rs b/polkadot/xcm/xcm-builder/src/currency_adapter.rs
index 86a2f54901558cdc4fc356696df8a00c5533c2f7..dfdfd4c6964a482ecb8a87fcd536cd4231d32b8f 100644
--- a/polkadot/xcm/xcm-builder/src/currency_adapter.rs
+++ b/polkadot/xcm/xcm-builder/src/currency_adapter.rs
@@ -17,8 +17,8 @@
//! Adapters to work with `frame_support::traits::Currency` through XCM.
use frame_support::traits::{ExistenceRequirement::AllowDeath, Get, WithdrawReasons};
-use sp_runtime::traits::{CheckedSub, SaturatedConversion};
-use sp_std::{convert::TryInto, marker::PhantomData, result};
+use sp_runtime::traits::CheckedSub;
+use sp_std::{marker::PhantomData, result};
use xcm::latest::{Error as XcmError, MultiAsset, MultiLocation, Result};
use xcm_executor::{
traits::{Convert, MatchesFungible, TransactAsset},
@@ -31,8 +31,6 @@ enum Error {
AssetNotFound,
/// `MultiLocation` to `AccountId` conversion failed.
AccountIdConversionFailed,
- /// `u128` amount to currency `Balance` conversion failed.
- AmountToBalanceConversionFailed,
}
impl From<Error> for XcmError {
@@ -41,8 +39,6 @@ impl From<Error> for XcmError {
match e {
Error::AssetNotFound => XcmError::AssetNotFound,
Error::AccountIdConversionFailed => FailedToTransactAsset("AccountIdConversionFailed"),
- Error::AmountToBalanceConversionFailed =>
- FailedToTransactAsset("AmountToBalanceConversionFailed"),
}
}
}
@@ -149,27 +145,37 @@ impl<
fn deposit_asset(what: &MultiAsset, who: &MultiLocation) -> Result {
log::trace!(target: "xcm::currency_adapter", "deposit_asset what: {:?}, who: {:?}", what, who);
// Check we handle this asset.
- let amount: u128 =
- Matcher::matches_fungible(&what).ok_or(Error::AssetNotFound)?.saturated_into();
+ let amount = Matcher::matches_fungible(&what).ok_or(Error::AssetNotFound)?;
let who =
AccountIdConverter::convert_ref(who).map_err(|()| Error::AccountIdConversionFailed)?;
- let balance_amount =
- amount.try_into().map_err(|_| Error::AmountToBalanceConversionFailed)?;
- let _imbalance = Currency::deposit_creating(&who, balance_amount);
+ let _imbalance = Currency::deposit_creating(&who, amount);
Ok(())
}
fn withdraw_asset(what: &MultiAsset, who: &MultiLocation) -> result::Result<Assets, XcmError> {
log::trace!(target: "xcm::currency_adapter", "withdraw_asset what: {:?}, who: {:?}", what, who);
// Check we handle this asset.
- let amount: u128 =
- Matcher::matches_fungible(what).ok_or(Error::AssetNotFound)?.saturated_into();
+ let amount = Matcher::matches_fungible(what).ok_or(Error::AssetNotFound)?;
let who =
AccountIdConverter::convert_ref(who).map_err(|()| Error::AccountIdConversionFailed)?;
- let balance_amount =
- amount.try_into().map_err(|_| Error::AmountToBalanceConversionFailed)?;
- Currency::withdraw(&who, balance_amount, WithdrawReasons::TRANSFER, AllowDeath)
+ Currency::withdraw(&who, amount, WithdrawReasons::TRANSFER, AllowDeath)
.map_err(|e| XcmError::FailedToTransactAsset(e.into()))?;
Ok(what.clone().into())
}
+
+ fn internal_transfer_asset(
+ asset: &MultiAsset,
+ from: &MultiLocation,
+ to: &MultiLocation,
+ ) -> result::Result<Assets, XcmError> {
+ log::trace!(target: "xcm::currency_adapter", "internal_transfer_asset asset: {:?}, from: {:?}, to: {:?}", asset, from, to);
+ let amount = Matcher::matches_fungible(asset).ok_or(Error::AssetNotFound)?;
+ let from =
+ AccountIdConverter::convert_ref(from).map_err(|()| Error::AccountIdConversionFailed)?;
+ let to =
+ AccountIdConverter::convert_ref(to).map_err(|()| Error::AccountIdConversionFailed)?;
+ Currency::transfer(&from, &to, amount, AllowDeath)
+ .map_err(|e| XcmError::FailedToTransactAsset(e.into()))?;
+ Ok(asset.clone().into())
+ }
}
diff --git a/polkadot/xcm/xcm-builder/src/fungibles_adapter.rs b/polkadot/xcm/xcm-builder/src/fungibles_adapter.rs
index 082e3b6955dfe1ab18b3fe04af48940d6db4ea1a..d06f92d97db9aa968b75bb3c395efa516352a7a8 100644
--- a/polkadot/xcm/xcm-builder/src/fungibles_adapter.rs
+++ b/polkadot/xcm/xcm-builder/src/fungibles_adapter.rs
@@ -118,14 +118,14 @@ impl<
AccountId: Clone, // can't get away without it since Currency is generic over it.
> TransactAsset for FungiblesTransferAdapter<Assets, Matcher, AccountIdConverter, AccountId>
{
- fn transfer_asset(
+ fn internal_transfer_asset(
what: &MultiAsset,
from: &MultiLocation,
to: &MultiLocation,
) -> result::Result<xcm_executor::Assets, XcmError> {
log::trace!(
target: "xcm::fungibles_adapter",
- "transfer_asset what: {:?}, from: {:?}, to: {:?}",
+ "internal_transfer_asset what: {:?}, from: {:?}, to: {:?}",
what, from, to
);
// Check we handle this asset.
@@ -325,12 +325,12 @@ impl<
>::withdraw_asset(what, who)
}
- fn transfer_asset(
+ fn internal_transfer_asset(
what: &MultiAsset,
from: &MultiLocation,
to: &MultiLocation,
) -> result::Result<xcm_executor::Assets, XcmError> {
- FungiblesTransferAdapter::<Assets, Matcher, AccountIdConverter, AccountId>::transfer_asset(
+ FungiblesTransferAdapter::<Assets, Matcher, AccountIdConverter, AccountId>::internal_transfer_asset(
what, from, to,
)
}
diff --git a/polkadot/xcm/xcm-builder/tests/mock/mod.rs b/polkadot/xcm/xcm-builder/tests/mock/mod.rs
index f11b628f65bc2f8203bf7026eb290eb282e92c7b..9599efcd7f29f3b420297400b2bc95f995b678f0 100644
--- a/polkadot/xcm/xcm-builder/tests/mock/mod.rs
+++ b/polkadot/xcm/xcm-builder/tests/mock/mod.rs
@@ -123,7 +123,7 @@ parameter_types! {
pub type SovereignAccountOf =
(ChildParachainConvertsVia<ParaId, AccountId>, AccountId32Aliases<KusamaNetwork, AccountId>);
-pub type LocalAssetTransactor = XcmCurrencyAdapter<
+pub type LocalCurrencyAdapter = XcmCurrencyAdapter<
Balances,
IsConcrete<KsmLocation>,
SovereignAccountOf,
@@ -131,6 +131,8 @@ pub type LocalAssetTransactor = XcmCurrencyAdapter<
CheckAccount,
>;
+pub type LocalAssetTransactor = (LocalCurrencyAdapter,);
+
type LocalOriginConverter = (
SovereignSignedViaLocation<SovereignAccountOf, Origin>,
ChildParachainAsNative<origin::Origin, Origin>,
diff --git a/polkadot/xcm/xcm-builder/tests/scenarios.rs b/polkadot/xcm/xcm-builder/tests/scenarios.rs
index 077a6590d57643e109cc1a7dc82af0b03adb7176..0bc6cfc8ce7da523889237b52248955315243410 100644
--- a/polkadot/xcm/xcm-builder/tests/scenarios.rs
+++ b/polkadot/xcm/xcm-builder/tests/scenarios.rs
@@ -17,7 +17,8 @@
mod mock;
use mock::{
- kusama_like_with_balances, AccountId, Balance, Balances, BaseXcmWeight, XcmConfig, CENTS,
+ kusama_like_with_balances, AccountId, Balance, Balances, BaseXcmWeight, System, XcmConfig,
+ CENTS,
};
use polkadot_parachain::primitives::Id as ParaId;
use sp_runtime::traits::AccountIdConversion;
@@ -66,6 +67,36 @@ fn withdraw_and_deposit_works() {
});
}
+/// Scenario:
+/// Alice simply wants to transfer funds to Bob's account via XCM.
+///
+/// Asserts that the balances are updated correctly and the correct events are fired.
+#[test]
+fn transfer_asset_works() {
+ let bob = AccountId::new([1u8; 32]);
+ let balances = vec![(ALICE, INITIAL_BALANCE), (bob.clone(), INITIAL_BALANCE)];
+ kusama_like_with_balances(balances).execute_with(|| {
+ let amount = REGISTER_AMOUNT;
+ let weight = BaseXcmWeight::get();
+ // Use `execute_xcm_in_credit` here to pass through the barrier
+ let r = XcmExecutor::<XcmConfig>::execute_xcm_in_credit(
+ AccountId32 { network: NetworkId::Any, id: ALICE.into() },
+ Xcm(vec![TransferAsset {
+ assets: (Here, amount).into(),
+ beneficiary: AccountId32 { network: NetworkId::Any, id: bob.clone().into() }.into(),
+ }]),
+ weight,
+ weight,
+ );
+ System::assert_last_event(
+ pallet_balances::Event::Transfer { from: ALICE, to: bob.clone(), amount }.into(),
+ );
+ assert_eq!(r, Outcome::Complete(weight));
+ assert_eq!(Balances::free_balance(ALICE), INITIAL_BALANCE - amount);
+ assert_eq!(Balances::free_balance(bob), INITIAL_BALANCE + amount);
+ });
+}
+
/// Scenario:
/// A parachain wants to be notified that a transfer worked correctly.
/// It includes a `QueryHolding` order after the deposit to get notified on success.
diff --git a/polkadot/xcm/xcm-executor/src/lib.rs b/polkadot/xcm/xcm-executor/src/lib.rs
index f57e72f2ac7d4bdb709da805b02cb567803b8289..a68f2db71b6c7e970715bad0906a0455087bc9a7 100644
--- a/polkadot/xcm/xcm-executor/src/lib.rs
+++ b/polkadot/xcm/xcm-executor/src/lib.rs
@@ -297,7 +297,7 @@ impl<Config: config::Config> XcmExecutor<Config> {
// Take `assets` from the origin account (on-chain) and place into dest account.
let origin = self.origin.as_ref().ok_or(XcmError::BadOrigin)?;
for asset in assets.inner() {
- Config::AssetTransactor::beam_asset(&asset, origin, &beneficiary)?;
+ Config::AssetTransactor::transfer_asset(&asset, origin, &beneficiary)?;
}
Ok(())
},
@@ -305,7 +305,7 @@ impl<Config: config::Config> XcmExecutor<Config> {
let origin = self.origin.as_ref().ok_or(XcmError::BadOrigin)?;
// Take `assets` from the origin account (on-chain) and place into dest account.
for asset in assets.inner() {
- Config::AssetTransactor::beam_asset(asset, origin, &dest)?;
+ Config::AssetTransactor::transfer_asset(asset, origin, &dest)?;
}
let ancestry = Config::LocationInverter::ancestry();
assets.reanchor(&dest, &ancestry).map_err(|()| XcmError::MultiLocationFull)?;
diff --git a/polkadot/xcm/xcm-executor/src/traits/transact_asset.rs b/polkadot/xcm/xcm-executor/src/traits/transact_asset.rs
index 78e2180ed7a4b2cac1a79a46356db8f5dde4fdae..5b8c37bb59a0a9961f5cacda760f09059f202769 100644
--- a/polkadot/xcm/xcm-executor/src/traits/transact_asset.rs
+++ b/polkadot/xcm/xcm-executor/src/traits/transact_asset.rs
@@ -78,7 +78,13 @@ pub trait TransactAsset {
/// Move an `asset` `from` one location in `to` another location.
///
/// Returns `XcmError::FailedToTransactAsset` if transfer failed.
- fn transfer_asset(
+ ///
+ /// ## Notes
+ /// This function is meant to only be implemented by the type implementing `TransactAsset`, and
+ /// not be called directly. Most common API usages will instead call `transfer_asset`, which in
+ /// turn has a default implementation that calls `internal_transfer_asset`. As such, **please
+ /// do not call this method directly unless you know what you're doing**.
+ fn internal_transfer_asset(
_asset: &MultiAsset,
_from: &MultiLocation,
_to: &MultiLocation,
@@ -88,13 +94,14 @@ pub trait TransactAsset {
/// Move an `asset` `from` one location in `to` another location.
///
- /// Attempts to use `transfer_asset` and if not available then falls back to using a two-part withdraw/deposit.
- fn beam_asset(
+ /// Attempts to use `internal_transfer_asset` and if not available then falls back to using a
+ /// two-part withdraw/deposit.
+ fn transfer_asset(
asset: &MultiAsset,
from: &MultiLocation,
to: &MultiLocation,
) -> Result<Assets, XcmError> {
- match Self::transfer_asset(asset, from, to) {
+ match Self::internal_transfer_asset(asset, from, to) {
Err(XcmError::Unimplemented) => {
let assets = Self::withdraw_asset(asset, from)?;
// Not a very forgiving attitude; once we implement roll-backs then it'll be nicer.
@@ -168,19 +175,19 @@ impl TransactAsset for Tuple {
Err(XcmError::AssetNotFound)
}
- fn transfer_asset(
+ fn internal_transfer_asset(
what: &MultiAsset,
from: &MultiLocation,
to: &MultiLocation,
) -> Result<Assets, XcmError> {
for_tuples!( #(
- match Tuple::transfer_asset(what, from, to) {
+ match Tuple::internal_transfer_asset(what, from, to) {
Err(XcmError::AssetNotFound) | Err(XcmError::Unimplemented) => (),
r => return r,
}
)* );
log::trace!(
- target: "xcm::TransactAsset::transfer_asset",
+ target: "xcm::TransactAsset::internal_transfer_asset",
"did not transfer asset: what: {:?}, from: {:?}, to: {:?}",
what,
from,
@@ -212,7 +219,7 @@ mod tests {
Err(XcmError::AssetNotFound)
}
- fn transfer_asset(
+ fn internal_transfer_asset(
_what: &MultiAsset,
_from: &MultiLocation,
_to: &MultiLocation,
@@ -235,7 +242,7 @@ mod tests {
Err(XcmError::Overflow)
}
- fn transfer_asset(
+ fn internal_transfer_asset(
_what: &MultiAsset,
_from: &MultiLocation,
_to: &MultiLocation,
@@ -258,7 +265,7 @@ mod tests {
Ok(Assets::default())
}
- fn transfer_asset(
+ fn internal_transfer_asset(
_what: &MultiAsset,
_from: &MultiLocation,
_to: &MultiLocation,