AssetsApi with MultiLocation as preparation for multi pallet_assets instances

Cargo.toml

@@ -35,6 +35,7 @@ members = [
 	"parachains/runtimes/testing/rococo-parachain",
 	"parachains/runtimes/starters/shell",
 	"parachains/runtimes/starters/seedling",
+	"parachains/runtimes/assets/common",
 	"parachains/runtimes/assets/statemint",
 	"parachains/runtimes/assets/statemine",
 	"parachains/runtimes/assets/westmint",

parachains/runtimes/assets/common/Cargo.toml

@@ -0,0 +1,40 @@
+[package]
+name = "assets-common"
+version = "0.1.0"
+authors = ["Parity Technologies <admin@parity.io>"]
+edition = "2021"
+description = "Assets common utilities"
+
+[dependencies]
+codec = { package = "parity-scale-codec", version = "3.0.0", default-features = false, features = ["derive"] }
+
+# Substrate
+frame-support = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "master" }
+sp-api = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "master" }
+sp-std = { git = "https://github.com/paritytech/substrate", default-features = false, branch = "master" }
+
+# Polkadot
+xcm = { git = "https://github.com/paritytech/polkadot", default-features = false, branch = "master" }
+xcm-builder = { git = "https://github.com/paritytech/polkadot", default-features = false, branch = "master" }
+xcm-executor = { git = "https://github.com/paritytech/polkadot", default-features = false, branch = "master" }
+
+# Cumulus
+parachains-common = { path = "../../../common", default-features = false }
+
+#[dev-dependencies]
+
+[build-dependencies]
+substrate-wasm-builder = { git = "https://github.com/paritytech/substrate", branch = "master" }
+
+[features]
+default = [ "std" ]
+std = [
+	"codec/std",
+	"frame-support/std",
+	"parachains-common/std",
+	"sp-api/std",
+	"sp-std/std",
+	"xcm/std",
+	"xcm-builder/std",
+	"xcm-executor/std",
+]

parachains/runtimes/assets/statemine/src/assets_api.rs → parachains/runtimes/assets/common/src/assets_api.rs

@@ -18,9 +18,17 @@
 
 //! Runtime API definition for assets.
 
-use codec::Codec;
+use codec::{Codec, Decode, Encode};
+use frame_support::RuntimeDebug;
 use sp_std::vec::Vec;
 
+/// The possible errors that can happen querying the storage of assets.
+#[derive(Eq, PartialEq, Encode, Decode, RuntimeDebug)]
+pub enum AssetsAccessError {
+	/// `MultiLocation` to `AssetId`/`ClassId` conversion failed.
+	AssetIdConversionFailed,
+}
+
 sp_api::decl_runtime_apis! {
 	pub trait AssetsApi<AccountId, AssetBalance, AssetId>
 	where
@@ -29,6 +37,6 @@ sp_api::decl_runtime_apis! {
 		AssetId: Codec,
 	{
 		/// Returns the list of `AssetId`s and corresponding balance that an `AccountId` has.
-		fn account_balances(account: AccountId) -> Vec<(AssetId, AssetBalance)>;
+		fn account_balances(account: AccountId) -> Result<Vec<(AssetId, AssetBalance)>, AssetsAccessError>;
 	}
 }

parachains/runtimes/assets/common/src/lib.rs

@@ -0,0 +1,78 @@
+// Copyright (C) 2023 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#![cfg_attr(not(feature = "std"), no_std)]
+
+pub mod assets_api;
+
+use parachains_common::AssetIdForTrustBackedAssets;
+use sp_std::prelude::Vec;
+use xcm::latest::MultiLocation;
+use xcm_builder::AsPrefixedGeneralIndex;
+use xcm_executor::traits::{Convert, JustTry};
+
+/// [`MultiLocation`] converter for [`TrustBackedAssets`]'s [`AssetIdForTrustBackedAssets`]
+pub type AssetIdForTrustBackedAssetsConvert<TrustBackedAssetsPalletLocation> =
+	AsPrefixedGeneralIndex<TrustBackedAssetsPalletLocation, AssetIdForTrustBackedAssets, JustTry>;
+
+/// Helper function to convert collections with (`AssetId`, 'Balance') to (`MultiLocation`, 'Balance')
+pub fn convert_asset_id<AssetId: Clone, Balance, ConvertAssetId>(
+	assets_balances: Vec<(AssetId, Balance)>,
+) -> Result<Vec<(MultiLocation, Balance)>, assets_api::AssetsAccessError>
+where
+	ConvertAssetId: Convert<MultiLocation, AssetId>,
+{
+	assets_balances
+		.into_iter()
+		.map(|(asset_id, balance)| {
+			ConvertAssetId::reverse_ref(asset_id)
+				.map(|converted_asset_id| (converted_asset_id, balance))
+				.map_err(|_| assets_api::AssetsAccessError::AssetIdConversionFailed)
+		})
+		.collect()
+}
+
+#[cfg(test)]
+mod tests {
+
+	use super::*;
+	use xcm::latest::prelude::*;
+
+	frame_support::parameter_types! {
+		pub TrustBackedAssetsPalletLocation: MultiLocation = MultiLocation::new(5, X1(PalletInstance(13)));
+	}
+
+	#[test]
+	fn asset_id_for_trust_backed_assets_convert_works() {
+		let local_asset_id = 123456789 as AssetIdForTrustBackedAssets;
+		let expected_reverse_ref =
+			MultiLocation::new(5, X2(PalletInstance(13), GeneralIndex(local_asset_id.into())));
+
+		assert_eq!(
+			AssetIdForTrustBackedAssetsConvert::<TrustBackedAssetsPalletLocation>::reverse_ref(
+				local_asset_id
+			)
+			.unwrap(),
+			expected_reverse_ref
+		);
+		assert_eq!(
+			AssetIdForTrustBackedAssetsConvert::<TrustBackedAssetsPalletLocation>::convert_ref(
+				expected_reverse_ref
+			)
+			.unwrap(),
+			local_asset_id
+		);
+	}
+}

parachains/runtimes/assets/statemine/Cargo.toml

@@ -49,6 +49,7 @@ pallet-state-trie-migration = { git = "https://github.com/paritytech/substrate",
 # Polkadot
 kusama-runtime-constants = { git = "https://github.com/paritytech/polkadot", default-features = false, branch = "master" }
 pallet-xcm = { git = "https://github.com/paritytech/polkadot", default-features = false, branch = "master" }
+pallet-xcm-benchmarks = { git = "https://github.com/paritytech/polkadot", branch = "master", default-features = false, optional = true }
 polkadot-core-primitives = { git = "https://github.com/paritytech/polkadot", default-features = false, branch = "master" }
 polkadot-parachain = { git = "https://github.com/paritytech/polkadot", default-features = false, branch = "master" }
 polkadot-runtime-common = { git = "https://github.com/paritytech/polkadot", default-features = false, branch = "master" }
@@ -69,8 +70,7 @@ cumulus-primitives-utility = { path = "../../../../primitives/utility", default-
 pallet-collator-selection = { path = "../../../../pallets/collator-selection", default-features = false }
 parachain-info = { path = "../../../pallets/parachain-info", default-features = false }
 parachains-common = { path = "../../../common", default-features = false }
-pallet-xcm-benchmarks = { git = "https://github.com/paritytech/polkadot", branch = "master", default-features = false, optional = true }
-
+assets-common = { path = "../common", default-features = false }
 
 [dev-dependencies]
 asset-test-utils = { path = "../test-utils"}
@@ -187,4 +187,5 @@ std = [
 	"pallet-collator-selection/std",
 	"parachain-info/std",
 	"parachains-common/std",
+	"assets-common/std",
 ]

parachains/runtimes/assets/statemine/src/lib.rs

@@ -24,7 +24,6 @@
 #[cfg(feature = "std")]
 include!(concat!(env!("OUT_DIR"), "/wasm_binary.rs"));
 
-pub mod assets_api;
 pub mod constants;
 mod weights;
 pub mod xcm_config;
@@ -65,7 +64,7 @@ use parachains_common::{
 	Index, Signature, AVERAGE_ON_INITIALIZE_RATIO, HOURS, MAXIMUM_BLOCK_WEIGHT,
 	NORMAL_DISPATCH_RATIO, SLOT_DURATION,
 };
-use xcm_config::{KsmLocation, XcmConfig};
+use xcm_config::{AssetIdForTrustBackedAssetsConvert, KsmLocation, XcmConfig};
 
 #[cfg(any(feature = "std", test))]
 pub use sp_runtime::BuildStorage;
@@ -832,15 +831,17 @@ impl_runtime_apis! {
 		}
 	}
 
-	impl assets_api::AssetsApi<
+	impl assets_common::assets_api::AssetsApi<
 		Block,
 		AccountId,
 		Balance,
-		AssetIdForTrustBackedAssets,
+		xcm::latest::MultiLocation,
 	> for Runtime
 	{
-		fn account_balances(account: AccountId) -> Vec<(AssetIdForTrustBackedAssets, Balance)> {
-			Assets::account_balances(account)
+		fn account_balances(account: AccountId) -> Result<Vec<(xcm::latest::MultiLocation, Balance)>, assets_common::assets_api::AssetsAccessError> {
+			Ok([
+				assets_common::convert_asset_id::<_, _, AssetIdForTrustBackedAssetsConvert>(Assets::account_balances(account))?,
+			].concat())
 		}
 	}
 

parachains/runtimes/assets/statemine/src/xcm_config.rs

@@ -34,12 +34,11 @@ use sp_runtime::traits::ConvertInto;
 use xcm::latest::prelude::*;
 use xcm_builder::{
 	AccountId32Aliases, AllowExplicitUnpaidExecutionFrom, AllowKnownQueryResponses,
-	AllowSubscriptionsFrom, AllowTopLevelPaidExecutionFrom, AsPrefixedGeneralIndex,
-	ConvertedConcreteId, CurrencyAdapter, EnsureXcmOrigin, FungiblesAdapter, IsConcrete, LocalMint,
-	NativeAsset, ParentAsSuperuser, ParentIsPreset, RelayChainAsNative, SiblingParachainAsNative,
-	SiblingParachainConvertsVia, SignedAccountId32AsNative, SignedToAccountId32,
-	SovereignSignedViaLocation, TakeWeightCredit, UsingComponents, WeightInfoBounds,
-	WithComputedOrigin,
+	AllowSubscriptionsFrom, AllowTopLevelPaidExecutionFrom, ConvertedConcreteId, CurrencyAdapter,
+	EnsureXcmOrigin, FungiblesAdapter, IsConcrete, LocalMint, NativeAsset, ParentAsSuperuser,
+	ParentIsPreset, RelayChainAsNative, SiblingParachainAsNative, SiblingParachainConvertsVia,
+	SignedAccountId32AsNative, SignedToAccountId32, SovereignSignedViaLocation, TakeWeightCredit,
+	UsingComponents, WeightInfoBounds, WithComputedOrigin,
 };
 use xcm_executor::{
 	traits::{JustTry, WithOriginFilter},
@@ -84,6 +83,10 @@ pub type CurrencyTransactor = CurrencyAdapter<
 	(),
 >;
 
+/// `AssetId` converter for [`AssetIdForTrustBackedAssets`]
+pub type AssetIdForTrustBackedAssetsConvert =
+	assets_common::AssetIdForTrustBackedAssetsConvert<TrustBackedAssetsPalletLocation>;
+
 /// Means for transacting assets besides the native currency on this chain.
 pub type FungiblesTransactor = FungiblesAdapter<
 	// Use this fungibles implementation:
@@ -92,11 +95,7 @@ pub type FungiblesTransactor = FungiblesAdapter<
 	ConvertedConcreteId<
 		AssetIdForTrustBackedAssets,
 		Balance,
-		AsPrefixedGeneralIndex<
-			TrustBackedAssetsPalletLocation,
-			AssetIdForTrustBackedAssets,
-			JustTry,
-		>,
+		AssetIdForTrustBackedAssetsConvert,
 		JustTry,
 	>,
 	// Convert an XCM MultiLocation into a local account id:
@@ -305,11 +304,7 @@ impl xcm_executor::Config for XcmConfig {
 			ConvertedConcreteId<
 				AssetIdForTrustBackedAssets,
 				Balance,
-				AsPrefixedGeneralIndex<
-					TrustBackedAssetsPalletLocation,
-					AssetIdForTrustBackedAssets,
-					JustTry,
-				>,
+				AssetIdForTrustBackedAssetsConvert,
 				JustTry,
 			>,
 			Assets,