Use xcm-handler to execute XCM locally

xcm-support/src/lib.rs

@@ -12,10 +12,14 @@ use sp_std::{
 	result,
 };
 
-use xcm::v0::{Error, Junction, MultiAsset, MultiLocation, Result};
+use xcm::v0::{Error, Junction, MultiAsset, MultiLocation, Result, Xcm};
 use xcm_executor::traits::{FilterAssetLocation, LocationConversion, MatchesFungible, NativeAsset, TransactAsset};
 
-use frame_support::{log, traits::Get};
+use frame_support::{dispatch::DispatchResult, log, traits::Get};
+
+pub trait XcmHandler<AccountId> {
+	fn execute_xcm(origin: AccountId, xcm: Xcm) -> DispatchResult;
+}
 
 pub trait CurrencyIdConversion<CurrencyId> {
 	fn from_asset(asset: &MultiAsset) -> Option<CurrencyId>;

xtokens/Cargo.toml

@@ -20,7 +20,8 @@ frame-system = { git = "https://github.com/paritytech/substrate", branch = "roco
 cumulus-primitives-core = { git = "https://github.com/paritytech/cumulus", branch = "rococo-v1", default-features = false }
 
 xcm = { git = "https://github.com/paritytech/polkadot", branch = "rococo-v1", default-features = false }
-xcm-executor = { git = "https://github.com/paritytech/polkadot", branch = "rococo-v1", default-features = false }
+
+orml-xcm-support = { path = "../xcm-support", default-features = false }
 
 [dev-dependencies]
 sp-core = { git = "https://github.com/paritytech/substrate", branch = "rococo-v1" }
@@ -39,4 +40,5 @@ std = [
 	"frame-system/std",
 	"cumulus-primitives-core/std",
 	"xcm/std",
+	"orml-xcm-support/std",
 ]

xtokens/src/lib.rs

@@ -17,8 +17,9 @@ pub mod module {
 	use sp_std::prelude::*;
 
 	use cumulus_primitives_core::{relay_chain::Balance as RelayChainBalance, ParaId};
-	use xcm::v0::{Error as XcmError, ExecuteXcm, Junction, MultiAsset, MultiLocation, NetworkId, Order, Xcm};
-	use xcm_executor::traits::LocationConversion;
+	use xcm::v0::{Junction, MultiAsset, MultiLocation, NetworkId, Order, Xcm};
+
+	use orml_xcm_support::XcmHandler;
 
 	#[derive(Encode, Decode, Eq, PartialEq, Clone, Copy, RuntimeDebug)]
 	/// Identity of chain.
@@ -64,19 +65,21 @@ pub mod module {
 			+ MaybeSerializeDeserialize
 			+ Into<u128>;
 
-		/// Convertor `Balance` to `RelayChainBalance`.
+		/// Convert `Balance` to `RelayChainBalance`.
 		type ToRelayChainBalance: Convert<Self::Balance, RelayChainBalance>;
 
+		/// Convert `Self::Account` to `AccountId32`
 		type AccountId32Convert: Convert<Self::AccountId, [u8; 32]>;
 
+		/// The network id of relay chain. Typically `NetworkId::Polkadot` or
+		/// `NetworkId::Kusama`.
 		type RelayChainNetworkId: Get<NetworkId>;
 
-		/// Parachain ID.
+		/// Self parachain ID.
 		type ParaId: Get<ParaId>;
 
-		type AccountIdConverter: LocationConversion<Self::AccountId>;
-
-		type XcmExecutor: ExecuteXcm;
+		/// Xcm handler to execute XCM.
+		type XcmHandler: XcmHandler<Self::AccountId>;
 	}
 
 	#[pallet::event]
@@ -85,23 +88,13 @@ pub mod module {
 		/// Transferred to relay chain. \[src, dest, amount\]
 		TransferredToRelayChain(T::AccountId, T::AccountId, T::Balance),
 
-		/// Transfer to relay chain failed. \[src, dest, amount, error\]
-		TransferToRelayChainFailed(T::AccountId, T::AccountId, T::Balance, XcmError),
-
 		/// Transferred to parachain. \[x_currency_id, src, para_id, dest,
 		/// dest_network, amount\]
 		TransferredToParachain(XCurrencyId, T::AccountId, ParaId, MultiLocation, T::Balance),
-
-		/// Transfer to parachain failed. \[x_currency_id, src, para_id, dest,
-		/// dest_network, amount, error\]
-		TransferToParachainFailed(XCurrencyId, T::AccountId, ParaId, MultiLocation, T::Balance, XcmError),
 	}
 
 	#[pallet::error]
-	pub enum Error<T> {
-		/// Bad location.
-		BadLocation,
-	}
+	pub enum Error<T> {}
 
 	#[pallet::hooks]
 	impl<T: Config> Hooks<T::BlockNumber> for Pallet<T> {}
@@ -138,15 +131,9 @@ pub mod module {
 					}],
 				}],
 			};
+			T::XcmHandler::execute_xcm(who.clone(), xcm)?;
 
-			let xcm_origin =
-				T::AccountIdConverter::try_into_location(who.clone()).map_err(|_| Error::<T>::BadLocation)?;
-			// TODO: revert state on xcm execution failure.
-			match T::XcmExecutor::execute_xcm(xcm_origin, xcm) {
-				Ok(_) => Self::deposit_event(Event::<T>::TransferredToRelayChain(who, dest, amount)),
-				Err(err) => Self::deposit_event(Event::<T>::TransferToRelayChainFailed(who, dest, amount, err)),
-			}
-
+			Self::deposit_event(Event::<T>::TransferredToRelayChain(who, dest, amount));
 			Ok(().into())
 		}
 
@@ -182,28 +169,15 @@ pub mod module {
 					}
 				}
 			};
+			T::XcmHandler::execute_xcm(who.clone(), xcm)?;
 
-			let xcm_origin =
-				T::AccountIdConverter::try_into_location(who.clone()).map_err(|_| Error::<T>::BadLocation)?;
-			// TODO: revert state on xcm execution failure.
-			match T::XcmExecutor::execute_xcm(xcm_origin, xcm) {
-				Ok(_) => Self::deposit_event(Event::<T>::TransferredToParachain(
-					x_currency_id,
-					who,
-					para_id,
-					dest,
-					amount,
-				)),
-				Err(err) => Self::deposit_event(Event::<T>::TransferToParachainFailed(
-					x_currency_id,
-					who,
-					para_id,
-					dest,
-					amount,
-					err,
-				)),
-			}
-
+			Self::deposit_event(Event::<T>::TransferredToParachain(
+				x_currency_id,
+				who,
+				para_id,
+				dest,
+				amount,
+			));
 			Ok(().into())
 		}
 	}