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// Copyright 2019-2022 PureStake Inc.
// This file is part of Moonbeam.
// Moonbeam 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.
// Moonbeam 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 Moonbeam. If not, see <http://www.gnu.org/licenses/>.
//! Precompile to xcm utils runtime methods via the EVM
#![cfg_attr(not(feature = "std"), no_std)]
use fp_evm::PrecompileHandle;
use frame_support::traits::ConstU32;
use frame_support::{
dispatch::{GetDispatchInfo, PostDispatchInfo},
traits::OriginTrait,
};
use pallet_evm::AddressMapping;
use parity_scale_codec::{Decode, DecodeLimit, MaxEncodedLen};
use precompile_utils::precompile_set::SelectorFilter;
use precompile_utils::prelude::*;
use sp_core::{H160, U256};
use sp_runtime::traits::Dispatchable;
use sp_std::boxed::Box;
use sp_std::marker::PhantomData;
use sp_std::vec;
use sp_std::vec::Vec;
use sp_weights::Weight;
use xcm::{latest::prelude::*, VersionedXcm, MAX_XCM_DECODE_DEPTH};
use xcm_executor::traits::ConvertOrigin;
use xcm_executor::traits::WeightBounds;
use xcm_executor::traits::WeightTrader;
use xcm_primitives::DEFAULT_PROOF_SIZE;
pub type XcmOriginOf<XcmConfig> =
<<XcmConfig as xcm_executor::Config>::RuntimeCall as Dispatchable>::RuntimeOrigin;
pub type XcmAccountIdOf<XcmConfig> =
<<<XcmConfig as xcm_executor::Config>::RuntimeCall as Dispatchable>
::RuntimeOrigin as OriginTrait>::AccountId;
pub type CallOf<Runtime> = <Runtime as pallet_xcm::Config>::RuntimeCall;
pub const XCM_SIZE_LIMIT: u32 = 2u32.pow(16);
type GetXcmSizeLimit = ConstU32<XCM_SIZE_LIMIT>;
#[cfg(test)]
mod mock;
mod tests;
#[derive(Debug)]
pub struct AllExceptXcmExecute<Runtime, XcmConfig>(PhantomData<(Runtime, XcmConfig)>);
impl<Runtime, XcmConfig> SelectorFilter for AllExceptXcmExecute<Runtime, XcmConfig>
where
Runtime: pallet_evm::Config + frame_system::Config + pallet_xcm::Config,
XcmOriginOf<XcmConfig>: OriginTrait,
XcmAccountIdOf<XcmConfig>: Into<H160>,
XcmConfig: xcm_executor::Config,
<Runtime as frame_system::Config>::RuntimeCall:
Dispatchable<PostInfo = PostDispatchInfo> + Decode + GetDispatchInfo,
<<Runtime as frame_system::Config>::RuntimeCall as Dispatchable>::RuntimeOrigin:
From<Option<Runtime::AccountId>>,
<Runtime as frame_system::Config>::RuntimeCall: From<pallet_xcm::Call<Runtime>>,
{
fn is_allowed(_caller: H160, selector: Option<u32>) -> bool {
match selector {
None => true,
Some(selector) => {
!XcmUtilsPrecompileCall::<Runtime, XcmConfig>::xcm_execute_selectors()
.contains(&selector)
}
fn description() -> String {
"Allowed for all callers for all selectors except 'execute'".into()
/// A precompile to wrap the functionality from xcm-utils
pub struct XcmUtilsPrecompile<Runtime, XcmConfig>(PhantomData<(Runtime, XcmConfig)>);
#[precompile_utils::precompile]
impl<Runtime, XcmConfig> XcmUtilsPrecompile<Runtime, XcmConfig>
#[precompile::public("multilocationToAddress((uint8,bytes[]))")]
#[precompile::view]
fn multilocation_to_address(
handle: &mut impl PrecompileHandle,
location: Location,
) -> EvmResult<Address> {
// storage item: AssetTypeUnitsPerSecond
// max encoded len: hash (16) + Multilocation + u128 (16)
handle.record_db_read::<Runtime>(32 + Location::max_encoded_len())?;
let origin =
XcmConfig::OriginConverter::convert_origin(location, OriginKind::SovereignAccount)
.map_err(|_| {
RevertReason::custom("Failed multilocation conversion").in_field("location")
})?;
let account: H160 = origin
.into_signer()
.ok_or(
RevertReason::custom("Failed multilocation conversion").in_field("multilocation"),
)?
.into();
Ok(Address(account))
#[precompile::public("getUnitsPerSecond((uint8,bytes[]))")]
fn get_units_per_second(
) -> EvmResult<U256> {
// We will construct an asset with the max amount, and check how much we
// get in return to substract
let multiasset: xcm::latest::Asset = (location.clone(), u128::MAX).into();
let weight_per_second = 1_000_000_000_000u64;
let mut trader = <XcmConfig as xcm_executor::Config>::Trader::new();
let ctx = XcmContext {
origin: Some(location),
message_id: XcmHash::default(),
topic: None,
// buy_weight returns unused assets
let unused = trader
.buy_weight(
Weight::from_parts(weight_per_second, DEFAULT_PROOF_SIZE),
vec![multiasset.clone()].into(),
&ctx,
)
RevertReason::custom("Asset not supported as fee payment").in_field("multilocation")
// we just need to substract from u128::MAX the unused assets
if let Some(amount) = unused
.fungible
.get(&multiasset.id)
.map(|&value| u128::MAX.saturating_sub(value))
Ok(amount.into())
} else {
Err(revert(
"Weight was too expensive to be bought with this asset",
))
#[precompile::public("weightMessage(bytes)")]
fn weight_message(
_handle: &mut impl PrecompileHandle,
message: BoundedBytes<GetXcmSizeLimit>,
) -> EvmResult<u64> {
let message: Vec<u8> = message.into();
let msg =
VersionedXcm::<<XcmConfig as xcm_executor::Config>::RuntimeCall>::decode_all_with_depth_limit(
MAX_XCM_DECODE_DEPTH,
&mut message.as_slice(),
.map(Xcm::<<XcmConfig as xcm_executor::Config>::RuntimeCall>::try_from);
let result = match msg {
Ok(Ok(mut x)) => {
XcmConfig::Weigher::weight(&mut x).map_err(|_| revert("failed weighting"))
_ => Err(RevertReason::custom("Failed decoding")
.in_field("message")
.into()),
Ok(result?.ref_time())
#[precompile::public("xcmExecute(bytes,uint64)")]
fn xcm_execute(
weight: u64,
) -> EvmResult {
let origin = Runtime::AddressMapping::into_account_id(handle.context().caller);
let message: Vec<_> = message.to_vec();
let xcm = xcm::VersionedXcm::<CallOf<Runtime>>::decode_all_with_depth_limit(
xcm::MAX_XCM_DECODE_DEPTH,
.map_err(|_e| RevertReason::custom("Failed xcm decoding").in_field("message"))?;
let call = pallet_xcm::Call::<Runtime>::execute {
message: Box::new(xcm),
max_weight: Weight::from_parts(weight, DEFAULT_PROOF_SIZE),
RuntimeHelper::<Runtime>::try_dispatch(handle, Some(origin).into(), call, 0)?;
Ok(())
#[precompile::public("xcmSend((uint8,bytes[]),bytes)")]
fn xcm_send(
dest: Location,
let xcm = xcm::VersionedXcm::<()>::decode_all_with_depth_limit(
let call = pallet_xcm::Call::<Runtime>::send {
dest: Box::new(dest.into()),