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let response = Response::Version(xcm_version);
let message =
Xcm(vec![QueryResponse { query_id, response, max_weight }]);
let event = match T::XcmRouter::send_xcm(new_key.clone(), message) {
Ok(()) => {
VersionNotifyTargets::<T>::insert(
XCM_VERSION,
versioned_key,
(query_id, max_weight, xcm_version),
);
Event::VersionChangeNotified(new_key, xcm_version)
},
Err(e) => Event::NotifyTargetSendFail(new_key, query_id, e.into()),
};
Self::deposit_event(event);
weight_used.saturating_accrue(todo_vnt_notify_migrate_weight);
}
if weight_used >= weight_cutoff {
return (weight_used, Some(stage))
}
}
}
}
(weight_used, None)
}
/// Request that `dest` informs us of its version.
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pub fn request_version_notify(dest: impl Into<MultiLocation>) -> XcmResult {
let dest = dest.into();
let versioned_dest = VersionedMultiLocation::from(dest.clone());
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: 0 };
T::XcmRouter::send_xcm(dest, Xcm(vec![instruction]))?;
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.
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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)?;
T::XcmRouter::send_xcm(dest.clone(), Xcm(vec![UnsubscribeVersion]))?;
Queries::<T>::remove(query_id);
Ok(())
}
/// Relay an XCM `message` from a given `interior` location in this context to a given `dest`
/// location. A null `dest` is not handled.
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interior: impl Into<Junctions>,
dest: impl Into<MultiLocation>,
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mut message: Xcm<()>,
) -> Result<(), SendError> {
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let interior = interior.into();
let dest = dest.into();
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if interior != Junctions::Here {
message.0.insert(0, DescendOrigin(interior))
log::trace!(target: "xcm::send_xcm", "dest: {:?}, message: {:?}", &dest, &message);
pub fn check_account() -> T::AccountId {
const ID: PalletId = PalletId(*b"py/xcmch");
AccountIdConversion::<T::AccountId>::into_account_truncating(&ID)
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fn do_new_query(
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responder: impl Into<MultiLocation>,
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maybe_notify: Option<(u8, u8)>,
timeout: T::BlockNumber,
) -> u64 {
QueryCounter::<T>::mutate(|q| {
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let r = *q;
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Queries::<T>::insert(
r,
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QueryStatus::Pending {
responder: responder.into().into(),
maybe_notify,
timeout,
},
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);
r
})
}
/// 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.
///
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/// To check the status of the query, use `fn query()` passing the resultant `QueryId`
/// value.
pub fn report_outcome(
message: &mut Xcm<()>,
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responder: impl Into<MultiLocation>,
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timeout: T::BlockNumber,
) -> Result<QueryId, XcmError> {
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let responder = responder.into();
let dest = T::LocationInverter::invert_location(&responder)
.map_err(|()| XcmError::MultiLocationNotInvertible)?;
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let query_id = Self::new_query(responder, timeout);
let report_error = Xcm(vec![ReportError { dest, query_id, max_response_weight: 0 }]);
message.0.insert(0, SetAppendix(report_error));
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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.
///
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/// 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<()>,
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responder: impl Into<MultiLocation>,
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notify: impl Into<<T as Config>::Call>,
timeout: T::BlockNumber,
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let responder = responder.into();
let dest = T::LocationInverter::invert_location(&responder)
.map_err(|()| XcmError::MultiLocationNotInvertible)?;
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let notify: <T as Config>::Call = notify.into();
let max_response_weight = notify.get_dispatch_info().weight;
let query_id = Self::new_notify_query(responder, notify, timeout);
let report_error = Xcm(vec![ReportError { dest, query_id, max_response_weight }]);
message.0.insert(0, SetAppendix(report_error));
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}
/// Attempt to create a new query ID and register it as a query that is yet to respond.
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pub fn new_query(responder: impl Into<MultiLocation>, timeout: T::BlockNumber) -> u64 {
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Self::do_new_query(responder, None, timeout)
}
/// 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(
![Keith Yeung Keith Yeung's avatar](/assets/no_avatar-849f9c04a3a0d0cea2424ae97b27447dc64a7dbfae83c036c45b403392f0e8ba.png)
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responder: impl Into<MultiLocation>,
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notify: impl Into<<T as Config>::Call>,
timeout: T::BlockNumber,
) -> 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)
}
/// 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
}
}
/// 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,
);
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let versioned_dest = VersionedMultiLocation::from(dest.clone());
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();
} else {
let _ = q.try_push((versioned_dest, 1));
}
});
}
}
impl<T: Config> WrapVersion for Pallet<T> {
fn wrap_version<Call>(
dest: &MultiLocation,
xcm: impl Into<VersionedXcm<Call>>,
) -> Result<VersionedXcm<Call>, ()> {
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)))
}
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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 `Repsonse::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: u64) -> 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 };
T::XcmRouter::send_xcm(dest.clone(), Xcm(vec![instruction]))?;
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) -> 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) -> Weight {
if assets.is_empty() {
return 0
}
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.clone(), versioned));
// TODO #3735: Put the real weight in there.
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}
}
impl<T: Config> ClaimAssets for Pallet<T> {
fn claim_assets(
origin: &MultiLocation,
ticket: &MultiLocation,
assets: &MultiAssets,
) -> 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));
match AssetTraps::<T>::get(hash) {
0 => return false,
1 => AssetTraps::<T>::remove(hash),
n => AssetTraps::<T>::insert(hash, n - 1),
}
return true
}
}
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impl<T: Config> OnResponse for Pallet<T> {
fn expecting_response(origin: &MultiLocation, query_id: QueryId) -> bool {
match Queries::<T>::get(query_id) {
Some(QueryStatus::Pending { responder, .. }) =>
MultiLocation::try_from(responder).map_or(false, |r| origin == &r),
Some(QueryStatus::VersionNotifier { origin: r, .. }) =>
MultiLocation::try_from(r).map_or(false, |r| origin == &r),
_ => false,
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}
}
fn on_response(
origin: &MultiLocation,
query_id: QueryId,
response: Response,
max_weight: Weight,
) -> Weight {
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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.clone(),
query_id,
Some(o),
));
return 0
},
_ => {
Self::deposit_event(Event::InvalidResponder(
origin.clone(),
query_id,
None,
));
// TODO #3735: Correct weight for this.
return 0
},
};
// TODO #3735: Check max_weight is correct.
if !is_active {
Queries::<T>::insert(
query_id,
QueryStatus::VersionNotifier {
origin: origin.clone().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));
0
},
(response, Some(QueryStatus::Pending { responder, maybe_notify, .. })) => {
let responder = match MultiLocation::try_from(responder) {
Ok(r) => r,
Err(_) => {
Self::deposit_event(Event::InvalidResponderVersion(
origin.clone(),
query_id,
));
return 0
},
};
if origin != &responder {
Self::deposit_event(Event::InvalidResponder(
origin.clone(),
query_id,
Some(responder),
));
return 0
}
return match maybe_notify {
Some((pallet_index, call_index)) => {
// This is a bit horrible, but we happen to know that the `Call` will
// be built by `(pallet_index: u8, call_index: u8, QueryId, Response)`.
// So we just encode that and then re-encode to a real Call.
let bare = (pallet_index, call_index, query_id, response);
if let Ok(call) = bare
.using_encoded(|mut bytes| <T as Config>::Call::decode(&mut bytes))
{
Queries::<T>::remove(query_id);
let weight = call.get_dispatch_info().weight;
if weight > max_weight {
let e = Event::NotifyOverweight(
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query_id,
pallet_index,
call_index,
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);
Self::deposit_event(e);
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}
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let dispatch_origin = Origin::Response(origin.clone()).into();
match call.dispatch(dispatch_origin) {
Ok(post_info) => {
let e = Event::Notified(query_id, pallet_index, call_index);
Self::deposit_event(e);
post_info.actual_weight
},
Err(error_and_info) => {
let e = Event::NotifyDispatchError(
query_id,
pallet_index,
call_index,
);
Self::deposit_event(e);
// Not much to do with the result as it is. It's up to the parachain to ensure that the
// message makes sense.
error_and_info.post_info.actual_weight
},
}
.unwrap_or(weight)
} else {
let e =
Event::NotifyDecodeFailed(query_id, pallet_index, call_index);
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Self::deposit_event(e);
0
}
},
None => {
let e = Event::ResponseReady(query_id, response.clone());
Self::deposit_event(e);
let at = frame_system::Pallet::<T>::current_block_number();
let response = response.into();
Queries::<T>::insert(query_id, QueryStatus::Ready { response, at });
0
},
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}
},
_ => {
Self::deposit_event(Event::UnexpectedResponse(origin.clone(), query_id));
return 0
},
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}
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/// Ensure that the origin `o` represents an XCM (`Transact`) origin.
///
/// Returns `Ok` with the location of the XCM sender or an `Err` otherwise.
pub fn ensure_xcm<OuterOrigin>(o: OuterOrigin) -> Result<MultiLocation, BadOrigin>
where
OuterOrigin: Into<Result<Origin, OuterOrigin>>,
{
match o.into() {
Ok(Origin::Xcm(location)) => Ok(location),
_ => Err(BadOrigin),
}
}
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/// Ensure that the origin `o` represents an XCM response origin.
///
/// Returns `Ok` with the location of the responder or an `Err` otherwise.
pub fn ensure_response<OuterOrigin>(o: OuterOrigin) -> Result<MultiLocation, BadOrigin>
where
OuterOrigin: Into<Result<Origin, OuterOrigin>>,
{
match o.into() {
Ok(Origin::Response(location)) => Ok(location),
_ => Err(BadOrigin),
}
}
/// Filter for `MultiLocation` to find those which represent a strict majority approval of an identified
/// plurality.
///
/// May reasonably be used with `EnsureXcm`.
pub struct IsMajorityOfBody<Prefix, Body>(PhantomData<(Prefix, Body)>);
impl<Prefix: Get<MultiLocation>, Body: Get<BodyId>> Contains<MultiLocation>
fn contains(l: &MultiLocation) -> bool {
let maybe_suffix = l.match_and_split(&Prefix::get());
matches!(maybe_suffix, Some(Plurality { id, part }) if id == &Body::get() && part.is_majority())
/// `EnsureOrigin` implementation succeeding with a `MultiLocation` value to recognize and filter the
/// `Origin::Xcm` item.
pub struct EnsureXcm<F>(PhantomData<F>);
impl<O: OriginTrait + From<Origin>, F: Contains<MultiLocation>> EnsureOrigin<O> for EnsureXcm<F>
where
O::PalletsOrigin: From<Origin> + TryInto<Origin, Error = O::PalletsOrigin>,
{
type Success = MultiLocation;
fn try_origin(outer: O) -> Result<Self::Success, O> {
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caller.try_into().and_then(|o| match o {
Origin::Xcm(location) if F::contains(&location) => Ok(location),
Origin::Xcm(location) => Err(Origin::Xcm(location).into()),
o => Err(o.into()),
}
#[cfg(feature = "runtime-benchmarks")]
fn successful_origin() -> O {
O::from(Origin::Xcm(Here.into()))
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/// `EnsureOrigin` implementation succeeding with a `MultiLocation` value to recognize and filter
/// the `Origin::Response` item.
pub struct EnsureResponse<F>(PhantomData<F>);
impl<O: OriginTrait + From<Origin>, F: Contains<MultiLocation>> EnsureOrigin<O>
for EnsureResponse<F>
where
O::PalletsOrigin: From<Origin> + TryInto<Origin, Error = O::PalletsOrigin>,
{
type Success = MultiLocation;
fn try_origin(outer: O) -> Result<Self::Success, O> {
outer.try_with_caller(|caller| {
caller.try_into().and_then(|o| match o {
Origin::Response(responder) => Ok(responder),
o => Err(o.into()),
})
})
}
#[cfg(feature = "runtime-benchmarks")]
fn successful_origin() -> O {
O::from(Origin::Response(Here.into()))
}
}
/// A simple passthrough where we reuse the `MultiLocation`-typed XCM origin as the inner value of
/// this crate's `Origin::Xcm` value.
pub struct XcmPassthrough<Origin>(PhantomData<Origin>);
impl<Origin: From<crate::Origin>> ConvertOrigin<Origin> for XcmPassthrough<Origin> {
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fn convert_origin(
origin: impl Into<MultiLocation>,
kind: OriginKind,
) -> Result<Origin, MultiLocation> {
let origin = origin.into();
match kind {
OriginKind::Xcm => Ok(crate::Origin::Xcm(origin).into()),
_ => Err(origin),