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/// Transfer some assets from the local chain to the sovereign account of a destination
/// chain and forward a notification XCM.
/// Fee payment on the destination side is made from the asset in the `assets` vector of
/// index `fee_asset_item`, up to enough to pay for `weight_limit` of weight. If more weight
/// is needed than `weight_limit`, then the operation will fail and the assets send may be
/// at risk.
///
/// - `origin`: Must be capable of withdrawing the `assets` and executing XCM.
/// - `dest`: Destination context for the assets. Will typically be `X2(Parent, Parachain(..))` to send
/// from parachain to parachain, or `X1(Parachain(..))` to send from relay to parachain.
/// - `beneficiary`: A beneficiary location for the assets in the context of `dest`. Will generally be
/// an `AccountId32` value.
/// - `assets`: The assets to be withdrawn. This should include the assets used to pay the fee on the
/// `dest` side.
/// - `fee_asset_item`: The index into `assets` of the item which should be used to pay
/// fees.
/// - `weight_limit`: The remote-side weight limit, if any, for the XCM fee purchase.
let maybe_assets: Result<MultiAssets, ()> = (*assets.clone()).try_into();
let maybe_dest: Result<MultiLocation, ()> = (*dest.clone()).try_into();
match (maybe_assets, maybe_dest) {
(Ok(assets), Ok(dest)) => {
use sp_std::vec;
let mut message = Xcm(vec![
TransferReserveAsset { assets, dest, xcm: Xcm(vec![]) }
]);
T::Weigher::weight(&mut message).map_or(Weight::MAX, |w| T::WeightInfo::reserve_transfer_assets().saturating_add(w))
}
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}
})]
pub fn limited_reserve_transfer_assets(
origin: OriginFor<T>,
dest: Box<VersionedMultiLocation>,
beneficiary: Box<VersionedMultiLocation>,
assets: Box<VersionedMultiAssets>,
fee_asset_item: u32,
weight_limit: WeightLimit,
) -> DispatchResult {
Self::do_reserve_transfer_assets(
origin,
dest,
beneficiary,
assets,
fee_asset_item,
Some(weight_limit),
)
}
/// Teleport some assets from the local chain to some destination chain.
///
/// Fee payment on the destination side is made from the asset in the `assets` vector of
/// index `fee_asset_item`, up to enough to pay for `weight_limit` of weight. If more weight
/// is needed than `weight_limit`, then the operation will fail and the assets send may be
/// at risk.
///
/// - `origin`: Must be capable of withdrawing the `assets` and executing XCM.
/// - `dest`: Destination context for the assets. Will typically be `X2(Parent, Parachain(..))` to send
/// from parachain to parachain, or `X1(Parachain(..))` to send from relay to parachain.
/// - `beneficiary`: A beneficiary location for the assets in the context of `dest`. Will generally be
/// an `AccountId32` value.
/// - `assets`: The assets to be withdrawn. The first item should be the currency used to to pay the fee on the
/// `dest` side. May not be empty.
/// - `fee_asset_item`: The index into `assets` of the item which should be used to pay
/// fees.
/// - `weight_limit`: The remote-side weight limit, if any, for the XCM fee purchase.
#[pallet::weight({
let maybe_assets: Result<MultiAssets, ()> = (*assets.clone()).try_into();
let maybe_dest: Result<MultiLocation, ()> = (*dest.clone()).try_into();
match (maybe_assets, maybe_dest) {
(Ok(assets), Ok(dest)) => {
use sp_std::vec;
let mut message = Xcm(vec![
WithdrawAsset(assets),
InitiateTeleport { assets: Wild(All), dest, xcm: Xcm(vec![]) },
]);
T::Weigher::weight(&mut message).map_or(Weight::MAX, |w| T::WeightInfo::teleport_assets().saturating_add(w))
}
}
})]
pub fn limited_teleport_assets(
origin: OriginFor<T>,
dest: Box<VersionedMultiLocation>,
beneficiary: Box<VersionedMultiLocation>,
assets: Box<VersionedMultiAssets>,
fee_asset_item: u32,
weight_limit: WeightLimit,
) -> DispatchResult {
Self::do_teleport_assets(
origin,
dest,
beneficiary,
assets,
fee_asset_item,
Some(weight_limit),
)
}
/// Set or unset the global suspension state of the XCM executor.
///
/// - `origin`: Must be an origin specified by AdminOrigin.
/// - `suspended`: `true` to suspend, `false` to resume.
#[pallet::call_index(10)]
#[pallet::weight(T::WeightInfo::force_suspension())]
pub fn force_suspension(origin: OriginFor<T>, suspended: bool) -> DispatchResult {
T::AdminOrigin::ensure_origin(origin)?;
XcmExecutionSuspended::<T>::set(suspended);
Ok(())
}
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/// The maximum number of distinct assets allowed to be transferred in a single helper extrinsic.
const MAX_ASSETS_FOR_TRANSFER: usize = 2;
impl<T: Config> Pallet<T> {
fn do_reserve_transfer_assets(
origin: OriginFor<T>,
dest: Box<VersionedMultiLocation>,
beneficiary: Box<VersionedMultiLocation>,
assets: Box<VersionedMultiAssets>,
fee_asset_item: u32,
maybe_weight_limit: Option<WeightLimit>,
) -> DispatchResult {
let origin_location = T::ExecuteXcmOrigin::ensure_origin(origin)?;
let dest = (*dest).try_into().map_err(|()| Error::<T>::BadVersion)?;
let beneficiary: MultiLocation =
(*beneficiary).try_into().map_err(|()| Error::<T>::BadVersion)?;
let assets: MultiAssets = (*assets).try_into().map_err(|()| Error::<T>::BadVersion)?;
ensure!(assets.len() <= MAX_ASSETS_FOR_TRANSFER, Error::<T>::TooManyAssets);
let value = (origin_location, assets.into_inner());
ensure!(T::XcmReserveTransferFilter::contains(&value), Error::<T>::Filtered);
let (origin_location, assets) = value;
let context = T::UniversalLocation::get();
let fees = assets
.get(fee_asset_item as usize)
.ok_or(Error::<T>::Empty)?
.clone()
.reanchored(&dest, context)
.map_err(|_| Error::<T>::CannotReanchor)?;
let max_assets = assets.len() as u32;
let assets: MultiAssets = assets.into();
let weight_limit = match maybe_weight_limit {
Some(weight_limit) => weight_limit,
None => {
let fees = fees.clone();
let mut remote_message = Xcm(vec![
ReserveAssetDeposited(assets.clone()),
ClearOrigin,
BuyExecution { fees, weight_limit: Limited(Weight::zero()) },
DepositAsset { assets: Wild(AllCounted(max_assets)), beneficiary },
]);
// use local weight for remote message and hope for the best.
let remote_weight = T::Weigher::weight(&mut remote_message)
.map_err(|()| Error::<T>::UnweighableMessage)?;
Limited(remote_weight)
},
};
let xcm = Xcm(vec![
BuyExecution { fees, weight_limit },
DepositAsset { assets: Wild(AllCounted(max_assets)), beneficiary },
]);
let mut message = Xcm(vec![
SetFeesMode { jit_withdraw: true },
TransferReserveAsset { assets, dest, xcm },
]);
let weight =
T::Weigher::weight(&mut message).map_err(|()| Error::<T>::UnweighableMessage)?;
let hash = message.using_encoded(sp_io::hashing::blake2_256);
let outcome =
T::XcmExecutor::execute_xcm_in_credit(origin_location, message, hash, weight, weight);
Self::deposit_event(Event::Attempted(outcome));
Ok(())
}
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fn do_teleport_assets(
origin: OriginFor<T>,
dest: Box<VersionedMultiLocation>,
beneficiary: Box<VersionedMultiLocation>,
assets: Box<VersionedMultiAssets>,
fee_asset_item: u32,
maybe_weight_limit: Option<WeightLimit>,
) -> DispatchResult {
let origin_location = T::ExecuteXcmOrigin::ensure_origin(origin)?;
let dest = (*dest).try_into().map_err(|()| Error::<T>::BadVersion)?;
let beneficiary: MultiLocation =
(*beneficiary).try_into().map_err(|()| Error::<T>::BadVersion)?;
let assets: MultiAssets = (*assets).try_into().map_err(|()| Error::<T>::BadVersion)?;
ensure!(assets.len() <= MAX_ASSETS_FOR_TRANSFER, Error::<T>::TooManyAssets);
let value = (origin_location, assets.into_inner());
ensure!(T::XcmTeleportFilter::contains(&value), Error::<T>::Filtered);
let (origin_location, assets) = value;
let context = T::UniversalLocation::get();
let fees = assets
.get(fee_asset_item as usize)
.ok_or(Error::<T>::Empty)?
.clone()
.reanchored(&dest, context)
.map_err(|_| Error::<T>::CannotReanchor)?;
let max_assets = assets.len() as u32;
let assets: MultiAssets = assets.into();
let weight_limit = match maybe_weight_limit {
Some(weight_limit) => weight_limit,
None => {
let fees = fees.clone();
let mut remote_message = Xcm(vec![
ReceiveTeleportedAsset(assets.clone()),
ClearOrigin,
BuyExecution { fees, weight_limit: Limited(Weight::zero()) },
DepositAsset { assets: Wild(AllCounted(max_assets)), beneficiary },
]);
// use local weight for remote message and hope for the best.
let remote_weight = T::Weigher::weight(&mut remote_message)
.map_err(|()| Error::<T>::UnweighableMessage)?;
Limited(remote_weight)
},
};
let xcm = Xcm(vec![
BuyExecution { fees, weight_limit },
DepositAsset { assets: Wild(AllCounted(max_assets)), beneficiary },
]);
let mut message = Xcm(vec![
WithdrawAsset(assets),
SetFeesMode { jit_withdraw: true },
InitiateTeleport { assets: Wild(AllCounted(max_assets)), dest, xcm },
]);
let weight =
T::Weigher::weight(&mut message).map_err(|()| Error::<T>::UnweighableMessage)?;
let hash = message.using_encoded(sp_io::hashing::blake2_256);
let outcome =
T::XcmExecutor::execute_xcm_in_credit(origin_location, message, hash, weight, weight);
Self::deposit_event(Event::Attempted(outcome));
Ok(())
}
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/// Will always make progress, and will do its best not to use much more than `weight_cutoff`
/// in doing so.
pub(crate) fn check_xcm_version_change(
mut stage: VersionMigrationStage,
weight_cutoff: Weight,
) -> (Weight, Option<VersionMigrationStage>) {
let mut weight_used = Weight::zero();
let sv_migrate_weight = T::WeightInfo::migrate_supported_version();
let vn_migrate_weight = T::WeightInfo::migrate_version_notifiers();
let vnt_already_notified_weight = T::WeightInfo::already_notified_target();
let vnt_notify_weight = T::WeightInfo::notify_current_targets();
let vnt_migrate_weight = T::WeightInfo::migrate_version_notify_targets();
let vnt_migrate_fail_weight = T::WeightInfo::notify_target_migration_fail();
let vnt_notify_migrate_weight = T::WeightInfo::migrate_and_notify_old_targets();
use VersionMigrationStage::*;
if stage == MigrateSupportedVersion {
// We assume that supported XCM version only ever increases, so just cycle through lower
// XCM versioned from the current.
for v in 0..XCM_VERSION {
for (old_key, value) in SupportedVersion::<T>::drain_prefix(v) {
if let Ok(new_key) = old_key.into_latest() {
SupportedVersion::<T>::insert(XCM_VERSION, new_key, value);
}
weight_used.saturating_accrue(sv_migrate_weight);
if weight_used.any_gte(weight_cutoff) {
return (weight_used, Some(stage))
stage = MigrateVersionNotifiers;
}
if stage == MigrateVersionNotifiers {
for v in 0..XCM_VERSION {
for (old_key, value) in VersionNotifiers::<T>::drain_prefix(v) {
if let Ok(new_key) = old_key.into_latest() {
VersionNotifiers::<T>::insert(XCM_VERSION, new_key, value);
}
weight_used.saturating_accrue(vn_migrate_weight);
if weight_used.any_gte(weight_cutoff) {
return (weight_used, Some(stage))
if let NotifyCurrentTargets(maybe_last_raw_key) = stage {
let mut iter = match maybe_last_raw_key {
Some(k) => VersionNotifyTargets::<T>::iter_prefix_from(XCM_VERSION, k),
None => VersionNotifyTargets::<T>::iter_prefix(XCM_VERSION),
};
while let Some((key, value)) = iter.next() {
let (query_id, max_weight, target_xcm_version) = value;
let new_key: MultiLocation = match key.clone().try_into() {
Ok(k) if target_xcm_version != xcm_version => k,
_ => {
// We don't early return here since we need to be certain that we
// make some progress.
weight_used.saturating_accrue(vnt_already_notified_weight);
continue
},
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let response = Response::Version(xcm_version);
let message =
Xcm(vec![QueryResponse { query_id, response, max_weight, querier: None }]);
let event = match send_xcm::<T::XcmRouter>(new_key, message) {
Ok((_hash, cost)) => {
let value = (query_id, max_weight, xcm_version);
VersionNotifyTargets::<T>::insert(XCM_VERSION, key, value);
Event::VersionChangeNotified(new_key, xcm_version, cost)
},
Err(e) => {
VersionNotifyTargets::<T>::remove(XCM_VERSION, key);
Event::NotifyTargetSendFail(new_key, query_id, e.into())
},
};
Self::deposit_event(event);
weight_used.saturating_accrue(vnt_notify_weight);
if weight_used.any_gte(weight_cutoff) {
let last = Some(iter.last_raw_key().into());
return (weight_used, Some(NotifyCurrentTargets(last)))
}
}
stage = MigrateAndNotifyOldTargets;
}
if stage == MigrateAndNotifyOldTargets {
for v in 0..XCM_VERSION {
for (old_key, value) in VersionNotifyTargets::<T>::drain_prefix(v) {
let (query_id, max_weight, target_xcm_version) = value;
let new_key = match MultiLocation::try_from(old_key.clone()) {
Ok(k) => k,
Err(()) => {
Self::deposit_event(Event::NotifyTargetMigrationFail(old_key, value.0));
weight_used.saturating_accrue(vnt_migrate_fail_weight);
if weight_used.any_gte(weight_cutoff) {
return (weight_used, Some(stage))
}
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let versioned_key = LatestVersionedMultiLocation(&new_key);
if target_xcm_version == xcm_version {
VersionNotifyTargets::<T>::insert(XCM_VERSION, versioned_key, value);
weight_used.saturating_accrue(vnt_migrate_weight);
} else {
// Need to notify target.
let response = Response::Version(xcm_version);
let message = Xcm(vec![QueryResponse {
query_id,
response,
max_weight,
querier: None,
}]);
let event = match send_xcm::<T::XcmRouter>(new_key, message) {
Ok((_hash, cost)) => {
VersionNotifyTargets::<T>::insert(
XCM_VERSION,
versioned_key,
(query_id, max_weight, xcm_version),
);
Event::VersionChangeNotified(new_key, xcm_version, cost)
Err(e) => Event::NotifyTargetSendFail(new_key, query_id, e.into()),
Self::deposit_event(event);
weight_used.saturating_accrue(vnt_notify_migrate_weight);
}
if weight_used.any_gte(weight_cutoff) {
return (weight_used, Some(stage))
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/// Request that `dest` informs us of its version.
pub fn request_version_notify(dest: impl Into<MultiLocation>) -> XcmResult {
let dest = dest.into();
let versioned_dest = VersionedMultiLocation::from(dest);
let already = VersionNotifiers::<T>::contains_key(XCM_VERSION, &versioned_dest);
ensure!(!already, XcmError::InvalidLocation);
let query_id = QueryCounter::<T>::mutate(|q| {
let r = *q;
q.saturating_inc();
r
});
// TODO #3735: Correct weight.
let instruction = SubscribeVersion { query_id, max_response_weight: Weight::zero() };
let (_hash, cost) = send_xcm::<T::XcmRouter>(dest, Xcm(vec![instruction]))?;
Self::deposit_event(Event::VersionNotifyRequested(dest, cost));
VersionNotifiers::<T>::insert(XCM_VERSION, &versioned_dest, query_id);
let query_status =
QueryStatus::VersionNotifier { origin: versioned_dest, is_active: false };
Queries::<T>::insert(query_id, query_status);
Ok(())
}
/// Request that `dest` ceases informing us of its version.
pub fn unrequest_version_notify(dest: impl Into<MultiLocation>) -> XcmResult {
let dest = dest.into();
let versioned_dest = LatestVersionedMultiLocation(&dest);
let query_id = VersionNotifiers::<T>::take(XCM_VERSION, versioned_dest)
.ok_or(XcmError::InvalidLocation)?;
let (_hash, cost) = send_xcm::<T::XcmRouter>(dest, Xcm(vec![UnsubscribeVersion]))?;
Self::deposit_event(Event::VersionNotifyUnrequested(dest, cost));
Queries::<T>::remove(query_id);
Ok(())
}
/// Relay an XCM `message` from a given `interior` location in this context to a given `dest`
/// location. The `fee_payer` is charged for the delivery unless `None` in which case fees
/// are not charged (and instead borne by the chain).
pub fn send_xcm(
interior: impl Into<Junctions>,
dest: impl Into<MultiLocation>,
mut message: Xcm<()>,
) -> Result<XcmHash, SendError> {
let interior = interior.into();
let dest = dest.into();
let maybe_fee_payer = if interior != Junctions::Here {
message.0.insert(0, DescendOrigin(interior));
Some(interior.into())
} else {
None
};
log::debug!(target: "xcm::send_xcm", "dest: {:?}, message: {:?}", &dest, &message);
let (ticket, price) = validate_send::<T::XcmRouter>(dest, message)?;
if let Some(fee_payer) = maybe_fee_payer {
Self::charge_fees(fee_payer, price).map_err(|_| SendError::Fees)?;
pub fn check_account() -> T::AccountId {
const ID: PalletId = PalletId(*b"py/xcmch");
AccountIdConversion::<T::AccountId>::into_account_truncating(&ID)
}
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/// Create a new expectation of a query response with the querier being here.
fn do_new_query(
responder: impl Into<MultiLocation>,
maybe_notify: Option<(u8, u8)>,
timeout: T::BlockNumber,
match_querier: impl Into<MultiLocation>,
) -> u64 {
QueryCounter::<T>::mutate(|q| {
let r = *q;
q.saturating_inc();
Queries::<T>::insert(
r,
QueryStatus::Pending {
responder: responder.into().into(),
maybe_match_querier: Some(match_querier.into().into()),
maybe_notify,
timeout,
},
);
r
})
}
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/// Consume `message` and return another which is equivalent to it except that it reports
/// back the outcome.
///
/// - `message`: The message whose outcome should be reported.
/// - `responder`: The origin from which a response should be expected.
/// - `timeout`: The block number after which it is permissible for `notify` not to be
/// called even if a response is received.
///
/// `report_outcome` may return an error if the `responder` is not invertible.
///
/// It is assumed that the querier of the response will be `Here`.
///
/// To check the status of the query, use `fn query()` passing the resultant `QueryId`
/// value.
pub fn report_outcome(
message: &mut Xcm<()>,
responder: impl Into<MultiLocation>,
timeout: T::BlockNumber,
) -> Result<QueryId, XcmError> {
let responder = responder.into();
let destination = T::UniversalLocation::get()
.invert_target(&responder)
.map_err(|()| XcmError::LocationNotInvertible)?;
let query_id = Self::new_query(responder, timeout, Here);
let response_info = QueryResponseInfo { destination, query_id, max_weight: Weight::zero() };
let report_error = Xcm(vec![ReportError(response_info)]);
message.0.insert(0, SetAppendix(report_error));
Ok(query_id)
}
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/// Consume `message` and return another which is equivalent to it except that it reports
/// back the outcome and dispatches `notify` on this chain.
///
/// - `message`: The message whose outcome should be reported.
/// - `responder`: The origin from which a response should be expected.
/// - `notify`: A dispatchable function which will be called once the outcome of `message`
/// is known. It may be a dispatchable in any pallet of the local chain, but other than
/// the usual origin, it must accept exactly two arguments: `query_id: QueryId` and
/// `outcome: Response`, and in that order. It should expect that the origin is
/// `Origin::Response` and will contain the responder's location.
/// - `timeout`: The block number after which it is permissible for `notify` not to be
/// called even if a response is received.
///
/// `report_outcome_notify` may return an error if the `responder` is not invertible.
///
/// It is assumed that the querier of the response will be `Here`.
///
/// NOTE: `notify` gets called as part of handling an incoming message, so it should be
/// lightweight. Its weight is estimated during this function and stored ready for
/// weighing `ReportOutcome` on the way back. If it turns out to be heavier once it returns
/// then reporting the outcome will fail. Futhermore if the estimate is too high, then it
/// may be put in the overweight queue and need to be manually executed.
pub fn report_outcome_notify(
message: &mut Xcm<()>,
responder: impl Into<MultiLocation>,
notify: impl Into<<T as Config>::RuntimeCall>,
timeout: T::BlockNumber,
) -> Result<(), XcmError> {
let responder = responder.into();
let destination = T::UniversalLocation::get()
.invert_target(&responder)
.map_err(|()| XcmError::LocationNotInvertible)?;
let notify: <T as Config>::RuntimeCall = notify.into();
let max_weight = notify.get_dispatch_info().weight;
let query_id = Self::new_notify_query(responder, notify, timeout, Here);
let response_info = QueryResponseInfo { destination, query_id, max_weight };
let report_error = Xcm(vec![ReportError(response_info)]);
message.0.insert(0, SetAppendix(report_error));
Ok(())
}
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/// Attempt to create a new query ID and register it as a query that is yet to respond.
pub fn new_query(
responder: impl Into<MultiLocation>,
timeout: T::BlockNumber,
match_querier: impl Into<MultiLocation>,
) -> u64 {
Self::do_new_query(responder, None, timeout, match_querier)
}
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/// Attempt to create a new query ID and register it as a query that is yet to respond, and
/// which will call a dispatchable when a response happens.
pub fn new_notify_query(
responder: impl Into<MultiLocation>,
notify: impl Into<<T as Config>::RuntimeCall>,
timeout: T::BlockNumber,
match_querier: impl Into<MultiLocation>,
) -> u64 {
let notify = notify.into().using_encoded(|mut bytes| Decode::decode(&mut bytes)).expect(
"decode input is output of Call encode; Call guaranteed to have two enums; qed",
);
Self::do_new_query(responder, Some(notify), timeout, match_querier)
}
/// Attempt to remove and return the response of query with ID `query_id`.
///
/// Returns `None` if the response is not (yet) available.
pub fn take_response(query_id: QueryId) -> Option<(Response, T::BlockNumber)> {
if let Some(QueryStatus::Ready { response, at }) = Queries::<T>::get(query_id) {
let response = response.try_into().ok()?;
Queries::<T>::remove(query_id);
Self::deposit_event(Event::ResponseTaken(query_id));
Some((response, at))
} else {
None
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}
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/// Note that a particular destination to whom we would like to send a message is unknown
/// and queue it for version discovery.
fn note_unknown_version(dest: &MultiLocation) {
log::trace!(
target: "xcm::pallet_xcm::note_unknown_version",
"XCM version is unknown for destination: {:?}",
dest,
);
let versioned_dest = VersionedMultiLocation::from(*dest);
VersionDiscoveryQueue::<T>::mutate(|q| {
if let Some(index) = q.iter().position(|i| &i.0 == &versioned_dest) {
// exists - just bump the count.
q[index].1.saturating_inc();
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} else {
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}
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});
}
/// Withdraw given `assets` from the given `location` and pay as XCM fees.
///
/// Fails if:
/// - the `assets` are not known on this chain;
/// - the `assets` cannot be withdrawn with that location as the Origin.
fn charge_fees(location: MultiLocation, assets: MultiAssets) -> DispatchResult {
T::XcmExecutor::charge_fees(location, assets.clone())
.map_err(|_| Error::<T>::FeesNotMet)?;
Self::deposit_event(Event::FeesPaid(location, assets));
Ok(())
}
}
pub struct LockTicket<T: Config> {
sovereign_account: T::AccountId,
amount: BalanceOf<T>,
unlocker: MultiLocation,
item_index: Option<usize>,
}
impl<T: Config> xcm_executor::traits::Enact for LockTicket<T> {
fn enact(self) -> Result<(), xcm_executor::traits::LockError> {
use xcm_executor::traits::LockError::UnexpectedState;
let mut locks = LockedFungibles::<T>::get(&self.sovereign_account).unwrap_or_default();
match self.item_index {
Some(index) => {
ensure!(locks.len() > index, UnexpectedState);
ensure!(locks[index].1.try_as::<_>() == Ok(&self.unlocker), UnexpectedState);
locks[index].0 = locks[index].0.max(self.amount);
},
None => {
locks
.try_push((self.amount, self.unlocker.into()))
.map_err(|(_balance, _location)| UnexpectedState)?;
},
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}
LockedFungibles::<T>::insert(&self.sovereign_account, locks);
T::Currency::extend_lock(
*b"py/xcmlk",
&self.sovereign_account,
self.amount,
WithdrawReasons::all(),
);
Ok(())
}
}
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pub struct UnlockTicket<T: Config> {
sovereign_account: T::AccountId,
amount: BalanceOf<T>,
unlocker: MultiLocation,
}
impl<T: Config> xcm_executor::traits::Enact for UnlockTicket<T> {
fn enact(self) -> Result<(), xcm_executor::traits::LockError> {
use xcm_executor::traits::LockError::UnexpectedState;
let mut locks =
LockedFungibles::<T>::get(&self.sovereign_account).ok_or(UnexpectedState)?;
let mut maybe_remove_index = None;
let mut locked = BalanceOf::<T>::zero();
let mut found = false;
// We could just as well do with with an into_iter, filter_map and collect, however this way
// avoids making an allocation.
for (i, x) in locks.iter_mut().enumerate() {
if x.1.try_as::<_>().defensive() == Ok(&self.unlocker) {
x.0 = x.0.saturating_sub(self.amount);
if x.0.is_zero() {
maybe_remove_index = Some(i);
ensure!(found, UnexpectedState);
if let Some(remove_index) = maybe_remove_index {
locks.swap_remove(remove_index);
}
LockedFungibles::<T>::insert(&self.sovereign_account, locks);
let reasons = WithdrawReasons::all();
T::Currency::set_lock(*b"py/xcmlk", &self.sovereign_account, locked, reasons);
Ok(())
pub struct ReduceTicket<T: Config> {
key: (u32, T::AccountId, VersionedAssetId),
amount: u128,
locker: VersionedMultiLocation,
owner: VersionedMultiLocation,
}
impl<T: Config> xcm_executor::traits::Enact for ReduceTicket<T> {
fn enact(self) -> Result<(), xcm_executor::traits::LockError> {
use xcm_executor::traits::LockError::UnexpectedState;
let mut record = RemoteLockedFungibles::<T>::get(&self.key).ok_or(UnexpectedState)?;
ensure!(self.locker == record.locker && self.owner == record.owner, UnexpectedState);
ensure!(record.users == 0, UnexpectedState);
record.amount = record.amount.checked_sub(self.amount).ok_or(UnexpectedState)?;
if record.amount == 0 {
RemoteLockedFungibles::<T>::remove(&self.key);
} else {
RemoteLockedFungibles::<T>::insert(&self.key, &record);
impl<T: Config> xcm_executor::traits::AssetLock for Pallet<T> {
type LockTicket = LockTicket<T>;
type UnlockTicket = UnlockTicket<T>;
type ReduceTicket = ReduceTicket<T>;
fn prepare_lock(
unlocker: MultiLocation,
asset: MultiAsset,
owner: MultiLocation,
) -> Result<LockTicket<T>, xcm_executor::traits::LockError> {
use xcm_executor::traits::LockError::*;
let sovereign_account = T::SovereignAccountOf::convert_ref(&owner).map_err(|_| BadOwner)?;
let amount = T::CurrencyMatcher::matches_fungible(&asset).ok_or(UnknownAsset)?;
ensure!(T::Currency::free_balance(&sovereign_account) >= amount, AssetNotOwned);
let locks = LockedFungibles::<T>::get(&sovereign_account).unwrap_or_default();
let item_index = locks.iter().position(|x| x.1.try_as::<_>() == Ok(&unlocker));
ensure!(item_index.is_some() || locks.len() < T::MaxLockers::get() as usize, NoResources);
Ok(LockTicket { sovereign_account, amount, unlocker, item_index })
}
fn prepare_unlock(
unlocker: MultiLocation,
asset: MultiAsset,
owner: MultiLocation,
) -> Result<UnlockTicket<T>, xcm_executor::traits::LockError> {
use xcm_executor::traits::LockError::*;
let sovereign_account = T::SovereignAccountOf::convert_ref(&owner).map_err(|_| BadOwner)?;
let amount = T::CurrencyMatcher::matches_fungible(&asset).ok_or(UnknownAsset)?;
ensure!(T::Currency::free_balance(&sovereign_account) >= amount, AssetNotOwned);
let locks = LockedFungibles::<T>::get(&sovereign_account).unwrap_or_default();
let item_index =
locks.iter().position(|x| x.1.try_as::<_>() == Ok(&unlocker)).ok_or(NotLocked)?;
ensure!(locks[item_index].0 >= amount, NotLocked);
Ok(UnlockTicket { sovereign_account, amount, unlocker })
}
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fn note_unlockable(
locker: MultiLocation,
asset: MultiAsset,
mut owner: MultiLocation,
) -> Result<(), xcm_executor::traits::LockError> {
use xcm_executor::traits::LockError::*;
ensure!(T::TrustedLockers::contains(&locker, &asset), NotTrusted);
let amount = match asset.fun {
Fungible(a) => a,
NonFungible(_) => return Err(Unimplemented),
};
owner.remove_network_id();
let account = T::SovereignAccountOf::convert_ref(&owner).map_err(|_| BadOwner)?;
let locker = locker.into();
let owner = owner.into();
let id: VersionedAssetId = asset.id.into();
let key = (XCM_VERSION, account, id);
let mut record = RemoteLockedFungibleRecord { amount, owner, locker, users: 0 };
if let Some(old) = RemoteLockedFungibles::<T>::get(&key) {
// Make sure that the new record wouldn't clobber any old data.
ensure!(old.locker == record.locker && old.owner == record.owner, WouldClobber);
record.users = old.users;
record.amount = record.amount.max(old.amount);
RemoteLockedFungibles::<T>::insert(&key, record);
Ok(())
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fn prepare_reduce_unlockable(
locker: MultiLocation,
asset: MultiAsset,
mut owner: MultiLocation,
) -> Result<Self::ReduceTicket, xcm_executor::traits::LockError> {
use xcm_executor::traits::LockError::*;
let amount = match asset.fun {
Fungible(a) => a,
NonFungible(_) => return Err(Unimplemented),
};
owner.remove_network_id();
let sovereign_account = T::SovereignAccountOf::convert_ref(&owner).map_err(|_| BadOwner)?;
let locker = locker.into();
let owner = owner.into();
let id: VersionedAssetId = asset.id.into();
let key = (XCM_VERSION, sovereign_account, id);
let record = RemoteLockedFungibles::<T>::get(&key).ok_or(NotLocked)?;
// Make sure that the record contains what we expect and there's enough to unlock.
ensure!(locker == record.locker && owner == record.owner, WouldClobber);
ensure!(record.users == 0, InUse);
ensure!(record.amount >= amount, NotEnoughLocked);
Ok(ReduceTicket { key, amount, locker, owner })
}
}
impl<T: Config> WrapVersion for Pallet<T> {
fn wrap_version<RuntimeCall>(
dest: &MultiLocation,
xcm: impl Into<VersionedXcm<RuntimeCall>>,
) -> Result<VersionedXcm<RuntimeCall>, ()> {
SupportedVersion::<T>::get(XCM_VERSION, LatestVersionedMultiLocation(dest))
.or_else(|| {
Self::note_unknown_version(dest);
SafeXcmVersion::<T>::get()
})
.ok_or_else(|| {
log::trace!(
target: "xcm::pallet_xcm::wrap_version",
"Could not determine a version to wrap XCM for destination: {:?}",
dest,
);
()
})
.and_then(|v| xcm.into().into_version(v.min(XCM_VERSION)))
}
}
impl<T: Config> VersionChangeNotifier for Pallet<T> {
/// Start notifying `location` should the XCM version of this chain change.
///
/// When it does, this type should ensure a `QueryResponse` message is sent with the given
/// `query_id` & `max_weight` and with a `response` of `Response::Version`. This should happen
/// until/unless `stop` is called with the correct `query_id`.
///
/// If the `location` has an ongoing notification and when this function is called, then an
/// error should be returned.
fn start(
dest: &MultiLocation,
query_id: QueryId,
max_weight: Weight,
_context: &XcmContext,
) -> XcmResult {
let versioned_dest = LatestVersionedMultiLocation(dest);
let already = VersionNotifyTargets::<T>::contains_key(XCM_VERSION, versioned_dest);
ensure!(!already, XcmError::InvalidLocation);
let xcm_version = T::AdvertisedXcmVersion::get();
let response = Response::Version(xcm_version);
let instruction = QueryResponse { query_id, response, max_weight, querier: None };
let (_hash, cost) = send_xcm::<T::XcmRouter>(*dest, Xcm(vec![instruction]))?;
Self::deposit_event(Event::<T>::VersionNotifyStarted(*dest, cost));
let value = (query_id, max_weight, xcm_version);
VersionNotifyTargets::<T>::insert(XCM_VERSION, versioned_dest, value);
Ok(())
}
/// Stop notifying `location` should the XCM change. This is a no-op if there was never a
/// subscription.
fn stop(dest: &MultiLocation, _context: &XcmContext) -> XcmResult {
VersionNotifyTargets::<T>::remove(XCM_VERSION, LatestVersionedMultiLocation(dest));
Ok(())
}
/// Return true if a location is subscribed to XCM version changes.
fn is_subscribed(dest: &MultiLocation) -> bool {
let versioned_dest = LatestVersionedMultiLocation(dest);
VersionNotifyTargets::<T>::contains_key(XCM_VERSION, versioned_dest)
}
}
impl<T: Config> DropAssets for Pallet<T> {
fn drop_assets(origin: &MultiLocation, assets: Assets, _context: &XcmContext) -> Weight {
if assets.is_empty() {
return Weight::zero()
let versioned = VersionedMultiAssets::from(MultiAssets::from(assets));
let hash = BlakeTwo256::hash_of(&(&origin, &versioned));
AssetTraps::<T>::mutate(hash, |n| *n += 1);
Self::deposit_event(Event::AssetsTrapped(hash, *origin, versioned));
// TODO #3735: Put the real weight in there.
Weight::zero()
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impl<T: Config> ClaimAssets for Pallet<T> {
fn claim_assets(
origin: &MultiLocation,
ticket: &MultiLocation,
assets: &MultiAssets,
_context: &XcmContext,
) -> bool {
let mut versioned = VersionedMultiAssets::from(assets.clone());
match (ticket.parents, &ticket.interior) {
(0, X1(GeneralIndex(i))) =>
versioned = match versioned.into_version(*i as u32) {
Ok(v) => v,
Err(()) => return false,
},
(0, Here) => (),
_ => return false,
};
let hash = BlakeTwo256::hash_of(&(origin, versioned.clone()));
match AssetTraps::<T>::get(hash) {
0 => return false,
1 => AssetTraps::<T>::remove(hash),
n => AssetTraps::<T>::insert(hash, n - 1),
Self::deposit_event(Event::AssetsClaimed(hash, *origin, versioned));
return true
impl<T: Config> OnResponse for Pallet<T> {
fn expecting_response(
origin: &MultiLocation,
query_id: QueryId,
querier: Option<&MultiLocation>,
) -> bool {
match Queries::<T>::get(query_id) {
Some(QueryStatus::Pending { responder, maybe_match_querier, .. }) =>
MultiLocation::try_from(responder).map_or(false, |r| origin == &r) &&
maybe_match_querier.map_or(true, |match_querier| {
MultiLocation::try_from(match_querier).map_or(false, |match_querier| {
querier.map_or(false, |q| q == &match_querier)
})
}),
Some(QueryStatus::VersionNotifier { origin: r, .. }) =>
MultiLocation::try_from(r).map_or(false, |r| origin == &r),
_ => false,
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}
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fn on_response(
origin: &MultiLocation,
query_id: QueryId,
querier: Option<&MultiLocation>,
response: Response,
max_weight: Weight,
_context: &XcmContext,
) -> Weight {
match (response, Queries::<T>::get(query_id)) {
(
Response::Version(v),
Some(QueryStatus::VersionNotifier { origin: expected_origin, is_active }),
) => {
let origin: MultiLocation = match expected_origin.try_into() {
Ok(o) if &o == origin => o,
Ok(o) => {
Self::deposit_event(Event::InvalidResponder(*origin, query_id, Some(o)));
return Weight::zero()
},
_ => {
Self::deposit_event(Event::InvalidResponder(*origin, query_id, None));
// TODO #3735: Correct weight for this.
return Weight::zero()
},
};
// TODO #3735: Check max_weight is correct.
if !is_active {
Queries::<T>::insert(
query_id,
QueryStatus::VersionNotifier { origin: origin.into(), is_active: true },
}
// We're being notified of a version change.
SupportedVersion::<T>::insert(
XCM_VERSION,
LatestVersionedMultiLocation(&origin),
v,
);
Self::deposit_event(Event::SupportedVersionChanged(origin, v));
Weight::zero()
},
(
response,
Some(QueryStatus::Pending { responder, maybe_notify, maybe_match_querier, .. }),
) => {
if let Some(match_querier) = maybe_match_querier {
let match_querier = match MultiLocation::try_from(match_querier) {
Ok(mq) => mq,
Self::deposit_event(Event::InvalidQuerierVersion(*origin, query_id));
return Weight::zero()
if querier.map_or(true, |q| q != &match_querier) {
Self::deposit_event(Event::InvalidQuerier(
*origin,
}
let responder = match MultiLocation::try_from(responder) {
Ok(r) => r,
Err(_) => {
Self::deposit_event(Event::InvalidResponderVersion(*origin, query_id));
return Weight::zero()
},
};
if origin != &responder {
Self::deposit_event(Event::InvalidResponder(
*origin,
query_id,
Some(responder),
));