pezkuwi-subxt/polkadot/xcm/xcm-builder/src/origin_conversion.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/>.

//! Various implementations for `ConvertOrigin`.

use frame_support::traits::{EnsureOrigin, Get, GetBacking, OriginTrait};
use frame_system::RawOrigin as SystemRawOrigin;
use polkadot_parachain::primitives::IsSystem;
use sp_std::{convert::TryInto, marker::PhantomData};
use xcm::latest::{BodyId, BodyPart, Junction, Junctions::*, MultiLocation, NetworkId, OriginKind};
use xcm_executor::traits::{Convert, ConvertOrigin};

/// Sovereign accounts use the system's `Signed` origin with an account ID derived from the `LocationConverter`.
pub struct SovereignSignedViaLocation<LocationConverter, Origin>(
	PhantomData<(LocationConverter, Origin)>,
);
impl<LocationConverter: Convert<MultiLocation, Origin::AccountId>, Origin: OriginTrait>
	ConvertOrigin<Origin> for SovereignSignedViaLocation<LocationConverter, Origin>
where
	Origin::AccountId: Clone,
{
	fn convert_origin(origin: MultiLocation, kind: OriginKind) -> Result<Origin, MultiLocation> {
		if let OriginKind::SovereignAccount = kind {
			let location = LocationConverter::convert(origin)?;
			Ok(Origin::signed(location).into())
		} else {
			Err(origin)
		}
	}
}

pub struct ParentAsSuperuser<Origin>(PhantomData<Origin>);
impl<Origin: OriginTrait> ConvertOrigin<Origin> for ParentAsSuperuser<Origin> {
	fn convert_origin(origin: MultiLocation, kind: OriginKind) -> Result<Origin, MultiLocation> {
		if kind == OriginKind::Superuser && origin.contains_parents_only(1) {
			Ok(Origin::root())
		} else {
			Err(origin)
		}
	}
}

pub struct ChildSystemParachainAsSuperuser<ParaId, Origin>(PhantomData<(ParaId, Origin)>);
impl<ParaId: IsSystem + From<u32>, Origin: OriginTrait> ConvertOrigin<Origin>
	for ChildSystemParachainAsSuperuser<ParaId, Origin>
{
	fn convert_origin(origin: MultiLocation, kind: OriginKind) -> Result<Origin, MultiLocation> {
		match (kind, origin) {
			(
				OriginKind::Superuser,
				MultiLocation { parents: 0, interior: X1(Junction::Parachain(id)) },
			) if ParaId::from(id).is_system() => Ok(Origin::root()),
			(_, origin) => Err(origin),
		}
	}
}

pub struct SiblingSystemParachainAsSuperuser<ParaId, Origin>(PhantomData<(ParaId, Origin)>);
impl<ParaId: IsSystem + From<u32>, Origin: OriginTrait> ConvertOrigin<Origin>
	for SiblingSystemParachainAsSuperuser<ParaId, Origin>
{
	fn convert_origin(origin: MultiLocation, kind: OriginKind) -> Result<Origin, MultiLocation> {
		match (kind, origin) {
			(
				OriginKind::Superuser,
				MultiLocation { parents: 1, interior: X1(Junction::Parachain(id)) },
			) if ParaId::from(id).is_system() => Ok(Origin::root()),
			(_, origin) => Err(origin),
		}
	}
}

pub struct ChildParachainAsNative<ParachainOrigin, Origin>(PhantomData<(ParachainOrigin, Origin)>);
impl<ParachainOrigin: From<u32>, Origin: From<ParachainOrigin>> ConvertOrigin<Origin>
	for ChildParachainAsNative<ParachainOrigin, Origin>
{
	fn convert_origin(origin: MultiLocation, kind: OriginKind) -> Result<Origin, MultiLocation> {
		match (kind, origin) {
			(
				OriginKind::Native,
				MultiLocation { parents: 0, interior: X1(Junction::Parachain(id)) },
			) => Ok(Origin::from(ParachainOrigin::from(id))),
			(_, origin) => Err(origin),
		}
	}
}

pub struct SiblingParachainAsNative<ParachainOrigin, Origin>(
	PhantomData<(ParachainOrigin, Origin)>,
);
impl<ParachainOrigin: From<u32>, Origin: From<ParachainOrigin>> ConvertOrigin<Origin>
	for SiblingParachainAsNative<ParachainOrigin, Origin>
{
	fn convert_origin(origin: MultiLocation, kind: OriginKind) -> Result<Origin, MultiLocation> {
		match (kind, origin) {
			(
				OriginKind::Native,
				MultiLocation { parents: 1, interior: X1(Junction::Parachain(id)) },
			) => Ok(Origin::from(ParachainOrigin::from(id))),
			(_, origin) => Err(origin),
		}
	}
}

// Our Relay-chain has a native origin given by the `Get`ter.
pub struct RelayChainAsNative<RelayOrigin, Origin>(PhantomData<(RelayOrigin, Origin)>);
impl<RelayOrigin: Get<Origin>, Origin> ConvertOrigin<Origin>
	for RelayChainAsNative<RelayOrigin, Origin>
{
	fn convert_origin(origin: MultiLocation, kind: OriginKind) -> Result<Origin, MultiLocation> {
		if kind == OriginKind::Native && origin.contains_parents_only(1) {
			Ok(RelayOrigin::get())
		} else {
			Err(origin)
		}
	}
}

pub struct SignedAccountId32AsNative<Network, Origin>(PhantomData<(Network, Origin)>);
impl<Network: Get<NetworkId>, Origin: OriginTrait> ConvertOrigin<Origin>
	for SignedAccountId32AsNative<Network, Origin>
where
	Origin::AccountId: From<[u8; 32]>,
{
	fn convert_origin(origin: MultiLocation, kind: OriginKind) -> Result<Origin, MultiLocation> {
		match (kind, origin) {
			(
				OriginKind::Native,
				MultiLocation { parents: 0, interior: X1(Junction::AccountId32 { id, network }) },
			) if matches!(network, NetworkId::Any) || network == Network::get() =>
				Ok(Origin::signed(id.into())),
			(_, origin) => Err(origin),
		}
	}
}

pub struct SignedAccountKey20AsNative<Network, Origin>(PhantomData<(Network, Origin)>);
impl<Network: Get<NetworkId>, Origin: OriginTrait> ConvertOrigin<Origin>
	for SignedAccountKey20AsNative<Network, Origin>
where
	Origin::AccountId: From<[u8; 20]>,
{
	fn convert_origin(origin: MultiLocation, kind: OriginKind) -> Result<Origin, MultiLocation> {
		match (kind, origin) {
			(
				OriginKind::Native,
				MultiLocation { parents: 0, interior: X1(Junction::AccountKey20 { key, network }) },
			) if (matches!(network, NetworkId::Any) || network == Network::get()) =>
				Ok(Origin::signed(key.into())),
			(_, origin) => Err(origin),
		}
	}
}

/// `EnsureOrigin` barrier to convert from dispatch origin to XCM origin, if one exists.
pub struct EnsureXcmOrigin<Origin, Conversion>(PhantomData<(Origin, Conversion)>);
impl<Origin: OriginTrait + Clone, Conversion: Convert<Origin, MultiLocation>> EnsureOrigin<Origin>
	for EnsureXcmOrigin<Origin, Conversion>
where
	Origin::PalletsOrigin: PartialEq,
{
	type Success = MultiLocation;
	fn try_origin(o: Origin) -> Result<Self::Success, Origin> {
		let o = match Conversion::convert(o) {
			Ok(location) => return Ok(location),
			Err(o) => o,
		};
		// We institute a root fallback so root can always represent the context. This
		// guarantees that `successful_origin` will work.
		if o.caller() == Origin::root().caller() {
			Ok(Here.into())
		} else {
			Err(o)
		}
	}

	#[cfg(feature = "runtime-benchmarks")]
	fn successful_origin() -> Origin {
		Origin::root()
	}
}

/// `Convert` implementation to convert from some a `Signed` (system) `Origin` into an `AccountId32`.
///
/// Typically used when configuring `pallet-xcm` for allowing normal accounts to dispatch an XCM from an `AccountId32`
/// origin.
pub struct SignedToAccountId32<Origin, AccountId, Network>(
	PhantomData<(Origin, AccountId, Network)>,
);
impl<Origin: OriginTrait + Clone, AccountId: Into<[u8; 32]>, Network: Get<NetworkId>>
	Convert<Origin, MultiLocation> for SignedToAccountId32<Origin, AccountId, Network>
where
	Origin::PalletsOrigin: From<SystemRawOrigin<AccountId>>
		+ TryInto<SystemRawOrigin<AccountId>, Error = Origin::PalletsOrigin>,
{
	fn convert(o: Origin) -> Result<MultiLocation, Origin> {
		o.try_with_caller(|caller| match caller.try_into() {
			Ok(SystemRawOrigin::Signed(who)) =>
				Ok(Junction::AccountId32 { network: Network::get(), id: who.into() }.into()),
			Ok(other) => Err(other.into()),
			Err(other) => Err(other),
		})
	}
}

/// `Convert` implementation to convert from some an origin which implements `Backing` into a corresponding `Plurality`
/// `MultiLocation`.
///
/// Typically used when configuring `pallet-xcm` for allowing a collective's Origin to dispatch an XCM from a
/// `Plurality` origin.
pub struct BackingToPlurality<Origin, COrigin, Body>(PhantomData<(Origin, COrigin, Body)>);
impl<Origin: OriginTrait + Clone, COrigin: GetBacking, Body: Get<BodyId>>
	Convert<Origin, MultiLocation> for BackingToPlurality<Origin, COrigin, Body>
where
	Origin::PalletsOrigin: From<COrigin> + TryInto<COrigin, Error = Origin::PalletsOrigin>,
{
	fn convert(o: Origin) -> Result<MultiLocation, Origin> {
		o.try_with_caller(|caller| match caller.try_into() {
			Ok(co) => match co.get_backing() {
				Some(backing) => Ok(Junction::Plurality {
					id: Body::get(),
					part: BodyPart::Fraction { nom: backing.approvals, denom: backing.eligible },
				}
				.into()),
				None => Err(co.into()),
			},
			Err(other) => Err(other),
		})
	}
}