lib.rs

// Copyright 2020 Parity Technologies (UK) Ltd.
// This file is part of Polkadot.

// Polkadot is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Polkadot is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Polkadot.  If not, see <http://www.gnu.org/licenses/>.

#![cfg_attr(not(feature = "std"), no_std)]

mod location_conversion;
pub use location_conversion::{
	Account32Hash, ParentIsDefault, ChildParachainConvertsVia, SiblingParachainConvertsVia, AccountId32Aliases, AccountKey20Aliases,
};

mod origin_conversion;
pub use origin_conversion::{
	SovereignSignedViaLocation, ParentAsSuperuser, ChildSystemParachainAsSuperuser, SiblingSystemParachainAsSuperuser,
	ChildParachainAsNative, SiblingParachainAsNative, RelayChainAsNative, SignedAccountId32AsNative, SignedAccountKey20AsNative,
};

mod currency_adapter;
mod fungibles_adapter;
pub use currency_adapter::CurrencyAdapter;
pub use fungibles_adapter::FungiblesAdapter;

use sp_std::marker::PhantomData;
use xcm_executor::traits::InvertLocation;
use xcm::v0::{MultiLocation, Junction};
use frame_support::traits::Get;

/// Simple location inverter; give it this location's ancestry and it'll
pub struct LocationInverter<Ancestry>(PhantomData<Ancestry>);

impl<Ancestry: Get<MultiLocation>> InvertLocation for LocationInverter<Ancestry> {
	fn invert_location(location: &MultiLocation) -> MultiLocation {
		let mut ancestry = Ancestry::get();
		let mut result = location.clone();
		for (i, j) in location.iter_rev()
			.map(|j| match j {
				Junction::Parent => ancestry.take_first().unwrap_or(Junction::OnlyChild),
				_ => Junction::Parent,
			})
			.enumerate()
		{
			*result.at_mut(i).expect("location and result begin equal; same size; qed") = j;
		}
		result
	}
}