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xcm_runtime_apis/
conversions.rs

1// Copyright (C) Parity Technologies (UK) Ltd.
2// This file is part of Polkadot.
3// SPDX-License-Identifier: Apache-2.0
4
5// Licensed under the Apache License, Version 2.0 (the "License");
6// you may not use this file except in compliance with the License.
7// You may obtain a copy of the License at
8//
9// 	http://www.apache.org/licenses/LICENSE-2.0
10//
11// Unless required by applicable law or agreed to in writing, software
12// distributed under the License is distributed on an "AS IS" BASIS,
13// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14// See the License for the specific language governing permissions and
15// limitations under the License.
16
17//! Contains runtime APIs for useful conversions, such as between XCM `Location` and `AccountId`.
18
19use codec::{Decode, Encode};
20use scale_info::TypeInfo;
21use xcm::VersionedLocation;
22use xcm_executor::traits::ConvertLocation;
23
24sp_api::decl_runtime_apis! {
25	/// API for useful conversions between XCM `Location` and `AccountId`.
26	pub trait LocationToAccountApi<AccountId> where AccountId: Decode {
27		/// Converts `Location` to `AccountId`.
28		fn convert_location(location: VersionedLocation) -> Result<AccountId, Error>;
29	}
30}
31
32#[derive(Copy, Clone, Encode, Decode, Eq, PartialEq, Debug, TypeInfo)]
33pub enum Error {
34	/// Requested `Location` is not supported by the local conversion.
35	#[codec(index = 0)]
36	Unsupported,
37
38	/// Converting a versioned data structure from one version to another failed.
39	#[codec(index = 1)]
40	VersionedConversionFailed,
41}
42
43/// A helper implementation that can be used for `LocationToAccountApi` implementations.
44/// It is useful when you already have a `ConvertLocation<AccountId>` implementation and a default
45/// `Ss58Prefix`.
46pub struct LocationToAccountHelper<AccountId, Conversion>(
47	core::marker::PhantomData<(AccountId, Conversion)>,
48);
49impl<AccountId: Decode, Conversion: ConvertLocation<AccountId>>
50	LocationToAccountHelper<AccountId, Conversion>
51{
52	pub fn convert_location(location: VersionedLocation) -> Result<AccountId, Error> {
53		let location = location.try_into().map_err(|_| Error::VersionedConversionFailed)?;
54		Conversion::convert_location(&location).ok_or(Error::Unsupported)
55	}
56}