From 763d618313e10075c76d56c68d25409efe0887df Mon Sep 17 00:00:00 2001 From: Branislav Kontur Date: Tue, 26 Nov 2024 15:52:23 +0100 Subject: [PATCH 1/2] BACKPORT-CONFLICT --- polkadot/grafana/README.md | 2 +- polkadot/grafana/parachains/status.json | 2 +- polkadot/xcm/src/v3/traits.rs | 4 +- polkadot/xcm/src/v4/traits.rs | 4 +- polkadot/xcm/src/v5/traits.rs | 525 ++++++++++++++++++ .../xcm/xcm-builder/src/universal_exports.rs | 265 +++++++-- .../xcm/xcm-executor/src/traits/export.rs | 4 +- prdoc/pr_6645.prdoc | 14 + .../frame/examples/default-config/src/lib.rs | 4 +- 9 files changed, 771 insertions(+), 53 deletions(-) create mode 100644 polkadot/xcm/src/v5/traits.rs create mode 100644 prdoc/pr_6645.prdoc diff --git a/polkadot/grafana/README.md b/polkadot/grafana/README.md index e909fdd29a75..0ecb0b70515b 100644 --- a/polkadot/grafana/README.md +++ b/polkadot/grafana/README.md @@ -90,4 +90,4 @@ and issue statement or initiate dispute. - **Assignment delay tranches**. Approval voting is designed such that validators assigned to check a specific candidate are split up into equal delay tranches (0.5 seconds each). All validators checks are ordered by the delay tranche index. Early tranches of validators have the opportunity to check the candidate first before later tranches -that act as as backups in case of no shows. +that act as backups in case of no shows. diff --git a/polkadot/grafana/parachains/status.json b/polkadot/grafana/parachains/status.json index 5942cbdf4479..22250967848d 100644 --- a/polkadot/grafana/parachains/status.json +++ b/polkadot/grafana/parachains/status.json @@ -1405,7 +1405,7 @@ "type": "prometheus", "uid": "$data_source" }, - "description": "Approval voting requires that validators which are assigned to check a specific \ncandidate are split up into delay tranches (0.5s each). Then, all validators checks are ordered by the delay \ntranche index. Early tranches of validators will check the candidate first and later tranches act as as backups in case of no shows.", + "description": "Approval voting requires that validators which are assigned to check a specific \ncandidate are split up into delay tranches (0.5s each). Then, all validators checks are ordered by the delay \ntranche index. Early tranches of validators will check the candidate first and later tranches act as backups in case of no shows.", "gridPos": { "h": 9, "w": 18, diff --git a/polkadot/xcm/src/v3/traits.rs b/polkadot/xcm/src/v3/traits.rs index 7fa8824c3568..80520b1962e4 100644 --- a/polkadot/xcm/src/v3/traits.rs +++ b/polkadot/xcm/src/v3/traits.rs @@ -535,13 +535,13 @@ impl SendXcm for Tuple { } /// Convenience function for using a `SendXcm` implementation. Just interprets the `dest` and wraps -/// both in `Some` before passing them as as mutable references into `T::send_xcm`. +/// both in `Some` before passing them as mutable references into `T::send_xcm`. pub fn validate_send(dest: MultiLocation, msg: Xcm<()>) -> SendResult { T::validate(&mut Some(dest), &mut Some(msg)) } /// Convenience function for using a `SendXcm` implementation. Just interprets the `dest` and wraps -/// both in `Some` before passing them as as mutable references into `T::send_xcm`. +/// both in `Some` before passing them as mutable references into `T::send_xcm`. /// /// Returns either `Ok` with the price of the delivery, or `Err` with the reason why the message /// could not be sent. diff --git a/polkadot/xcm/src/v4/traits.rs b/polkadot/xcm/src/v4/traits.rs index 351de92c80ed..c4eec522ed03 100644 --- a/polkadot/xcm/src/v4/traits.rs +++ b/polkadot/xcm/src/v4/traits.rs @@ -289,13 +289,13 @@ impl SendXcm for Tuple { } /// Convenience function for using a `SendXcm` implementation. Just interprets the `dest` and wraps -/// both in `Some` before passing them as as mutable references into `T::send_xcm`. +/// both in `Some` before passing them as mutable references into `T::send_xcm`. pub fn validate_send(dest: Location, msg: Xcm<()>) -> SendResult { T::validate(&mut Some(dest), &mut Some(msg)) } /// Convenience function for using a `SendXcm` implementation. Just interprets the `dest` and wraps -/// both in `Some` before passing them as as mutable references into `T::send_xcm`. +/// both in `Some` before passing them as mutable references into `T::send_xcm`. /// /// Returns either `Ok` with the price of the delivery, or `Err` with the reason why the message /// could not be sent. diff --git a/polkadot/xcm/src/v5/traits.rs b/polkadot/xcm/src/v5/traits.rs new file mode 100644 index 000000000000..dd067b774fcd --- /dev/null +++ b/polkadot/xcm/src/v5/traits.rs @@ -0,0 +1,525 @@ +// Copyright (C) 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 . + +//! Cross-Consensus Message format data structures. + +pub use crate::v3::{Error as OldError, SendError, XcmHash}; +use codec::{Decode, Encode}; +use core::result; +use scale_info::TypeInfo; + +pub use sp_weights::Weight; + +use super::*; + +/// Error codes used in XCM. The first errors codes have explicit indices and are part of the XCM +/// format. Those trailing are merely part of the XCM implementation; there is no expectation that +/// they will retain the same index over time. +#[derive(Copy, Clone, Encode, Decode, Eq, PartialEq, Debug, TypeInfo)] +#[scale_info(replace_segment("staging_xcm", "xcm"))] +#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))] +pub enum Error { + // Errors that happen due to instructions being executed. These alone are defined in the + // XCM specification. + /// An arithmetic overflow happened. + #[codec(index = 0)] + Overflow, + /// The instruction is intentionally unsupported. + #[codec(index = 1)] + Unimplemented, + /// Origin Register does not contain a value value for a reserve transfer notification. + #[codec(index = 2)] + UntrustedReserveLocation, + /// Origin Register does not contain a value value for a teleport notification. + #[codec(index = 3)] + UntrustedTeleportLocation, + /// `MultiLocation` value too large to descend further. + #[codec(index = 4)] + LocationFull, + /// `MultiLocation` value ascend more parents than known ancestors of local location. + #[codec(index = 5)] + LocationNotInvertible, + /// The Origin Register does not contain a valid value for instruction. + #[codec(index = 6)] + BadOrigin, + /// The location parameter is not a valid value for the instruction. + #[codec(index = 7)] + InvalidLocation, + /// The given asset is not handled. + #[codec(index = 8)] + AssetNotFound, + /// An asset transaction (like withdraw or deposit) failed (typically due to type conversions). + #[codec(index = 9)] + FailedToTransactAsset(#[codec(skip)] &'static str), + /// An asset cannot be withdrawn, potentially due to lack of ownership, availability or rights. + #[codec(index = 10)] + NotWithdrawable, + /// An asset cannot be deposited under the ownership of a particular location. + #[codec(index = 11)] + LocationCannotHold, + /// Attempt to send a message greater than the maximum supported by the transport protocol. + #[codec(index = 12)] + ExceedsMaxMessageSize, + /// The given message cannot be translated into a format supported by the destination. + #[codec(index = 13)] + DestinationUnsupported, + /// Destination is routable, but there is some issue with the transport mechanism. + #[codec(index = 14)] + Transport(#[codec(skip)] &'static str), + /// Destination is known to be unroutable. + #[codec(index = 15)] + Unroutable, + /// Used by `ClaimAsset` when the given claim could not be recognized/found. + #[codec(index = 16)] + UnknownClaim, + /// Used by `Transact` when the functor cannot be decoded. + #[codec(index = 17)] + FailedToDecode, + /// Used by `Transact` to indicate that the given weight limit could be breached by the + /// functor. + #[codec(index = 18)] + MaxWeightInvalid, + /// Used by `BuyExecution` when the Holding Register does not contain payable fees. + #[codec(index = 19)] + NotHoldingFees, + /// Used by `BuyExecution` when the fees declared to purchase weight are insufficient. + #[codec(index = 20)] + TooExpensive, + /// Used by the `Trap` instruction to force an error intentionally. Its code is included. + #[codec(index = 21)] + Trap(u64), + /// Used by `ExpectAsset`, `ExpectError` and `ExpectOrigin` when the expectation was not true. + #[codec(index = 22)] + ExpectationFalse, + /// The provided pallet index was not found. + #[codec(index = 23)] + PalletNotFound, + /// The given pallet's name is different to that expected. + #[codec(index = 24)] + NameMismatch, + /// The given pallet's version has an incompatible version to that expected. + #[codec(index = 25)] + VersionIncompatible, + /// The given operation would lead to an overflow of the Holding Register. + #[codec(index = 26)] + HoldingWouldOverflow, + /// The message was unable to be exported. + #[codec(index = 27)] + ExportError, + /// `MultiLocation` value failed to be reanchored. + #[codec(index = 28)] + ReanchorFailed, + /// No deal is possible under the given constraints. + #[codec(index = 29)] + NoDeal, + /// Fees were required which the origin could not pay. + #[codec(index = 30)] + FeesNotMet, + /// Some other error with locking. + #[codec(index = 31)] + LockError, + /// The state was not in a condition where the operation was valid to make. + #[codec(index = 32)] + NoPermission, + /// The universal location of the local consensus is improper. + #[codec(index = 33)] + Unanchored, + /// An asset cannot be deposited, probably because (too much of) it already exists. + #[codec(index = 34)] + NotDepositable, + /// Too many assets matched the given asset filter. + #[codec(index = 35)] + TooManyAssets, + + // Errors that happen prior to instructions being executed. These fall outside of the XCM + // spec. + /// XCM version not able to be handled. + UnhandledXcmVersion, + /// Execution of the XCM would potentially result in a greater weight used than weight limit. + WeightLimitReached(Weight), + /// The XCM did not pass the barrier condition for execution. + /// + /// The barrier condition differs on different chains and in different circumstances, but + /// generally it means that the conditions surrounding the message were not such that the chain + /// considers the message worth spending time executing. Since most chains lift the barrier to + /// execution on appropriate payment, presentation of an NFT voucher, or based on the message + /// origin, it means that none of those were the case. + Barrier, + /// The weight of an XCM message is not computable ahead of execution. + WeightNotComputable, + /// Recursion stack limit reached + // TODO(https://github.com/paritytech/polkadot-sdk/issues/6199): This should have a fixed index since + // we use it in `FrameTransactionalProcessor` // which is used in instructions. + // Or we should create a different error for that. + ExceedsStackLimit, +} + +impl TryFrom for Error { + type Error = (); + fn try_from(old_error: OldError) -> result::Result { + use OldError::*; + Ok(match old_error { + Overflow => Self::Overflow, + Unimplemented => Self::Unimplemented, + UntrustedReserveLocation => Self::UntrustedReserveLocation, + UntrustedTeleportLocation => Self::UntrustedTeleportLocation, + LocationFull => Self::LocationFull, + LocationNotInvertible => Self::LocationNotInvertible, + BadOrigin => Self::BadOrigin, + InvalidLocation => Self::InvalidLocation, + AssetNotFound => Self::AssetNotFound, + FailedToTransactAsset(s) => Self::FailedToTransactAsset(s), + NotWithdrawable => Self::NotWithdrawable, + LocationCannotHold => Self::LocationCannotHold, + ExceedsMaxMessageSize => Self::ExceedsMaxMessageSize, + DestinationUnsupported => Self::DestinationUnsupported, + Transport(s) => Self::Transport(s), + Unroutable => Self::Unroutable, + UnknownClaim => Self::UnknownClaim, + FailedToDecode => Self::FailedToDecode, + MaxWeightInvalid => Self::MaxWeightInvalid, + NotHoldingFees => Self::NotHoldingFees, + TooExpensive => Self::TooExpensive, + Trap(i) => Self::Trap(i), + ExpectationFalse => Self::ExpectationFalse, + PalletNotFound => Self::PalletNotFound, + NameMismatch => Self::NameMismatch, + VersionIncompatible => Self::VersionIncompatible, + HoldingWouldOverflow => Self::HoldingWouldOverflow, + ExportError => Self::ExportError, + ReanchorFailed => Self::ReanchorFailed, + NoDeal => Self::NoDeal, + FeesNotMet => Self::FeesNotMet, + LockError => Self::LockError, + NoPermission => Self::NoPermission, + Unanchored => Self::Unanchored, + NotDepositable => Self::NotDepositable, + UnhandledXcmVersion => Self::UnhandledXcmVersion, + WeightLimitReached(weight) => Self::WeightLimitReached(weight), + Barrier => Self::Barrier, + WeightNotComputable => Self::WeightNotComputable, + ExceedsStackLimit => Self::ExceedsStackLimit, + }) + } +} + +impl MaxEncodedLen for Error { + fn max_encoded_len() -> usize { + // TODO: max_encoded_len doesn't quite work here as it tries to take notice of the fields + // marked `codec(skip)`. We can hard-code it with the right answer for now. + 1 + } +} + +impl From for Error { + fn from(e: SendError) -> Self { + match e { + SendError::NotApplicable | SendError::Unroutable | SendError::MissingArgument => + Error::Unroutable, + SendError::Transport(s) => Error::Transport(s), + SendError::DestinationUnsupported => Error::DestinationUnsupported, + SendError::ExceedsMaxMessageSize => Error::ExceedsMaxMessageSize, + SendError::Fees => Error::FeesNotMet, + } + } +} + +pub type Result = result::Result<(), Error>; + +/// Outcome of an XCM execution. +#[derive(Clone, Encode, Decode, Eq, PartialEq, Debug, TypeInfo)] +pub enum Outcome { + /// Execution completed successfully; given weight was used. + Complete { used: Weight }, + /// Execution started, but did not complete successfully due to the given error; given weight + /// was used. + Incomplete { used: Weight, error: Error }, + /// Execution did not start due to the given error. + Error { error: Error }, +} + +impl Outcome { + pub fn ensure_complete(self) -> Result { + match self { + Outcome::Complete { .. } => Ok(()), + Outcome::Incomplete { error, .. } => Err(error), + Outcome::Error { error, .. } => Err(error), + } + } + pub fn ensure_execution(self) -> result::Result { + match self { + Outcome::Complete { used, .. } => Ok(used), + Outcome::Incomplete { used, .. } => Ok(used), + Outcome::Error { error, .. } => Err(error), + } + } + /// How much weight was used by the XCM execution attempt. + pub fn weight_used(&self) -> Weight { + match self { + Outcome::Complete { used, .. } => *used, + Outcome::Incomplete { used, .. } => *used, + Outcome::Error { .. } => Weight::zero(), + } + } +} + +impl From for Outcome { + fn from(error: Error) -> Self { + Self::Error { error } + } +} + +pub trait PreparedMessage { + fn weight_of(&self) -> Weight; +} + +/// Type of XCM message executor. +pub trait ExecuteXcm { + type Prepared: PreparedMessage; + fn prepare(message: Xcm) -> result::Result>; + fn execute( + origin: impl Into, + pre: Self::Prepared, + id: &mut XcmHash, + weight_credit: Weight, + ) -> Outcome; + fn prepare_and_execute( + origin: impl Into, + message: Xcm, + id: &mut XcmHash, + weight_limit: Weight, + weight_credit: Weight, + ) -> Outcome { + let pre = match Self::prepare(message) { + Ok(x) => x, + Err(_) => return Outcome::Error { error: Error::WeightNotComputable }, + }; + let xcm_weight = pre.weight_of(); + if xcm_weight.any_gt(weight_limit) { + return Outcome::Error { error: Error::WeightLimitReached(xcm_weight) } + } + Self::execute(origin, pre, id, weight_credit) + } + + /// Deduct some `fees` to the sovereign account of the given `location` and place them as per + /// the convention for fees. + fn charge_fees(location: impl Into, fees: Assets) -> Result; +} + +pub enum Weightless {} +impl PreparedMessage for Weightless { + fn weight_of(&self) -> Weight { + unreachable!() + } +} + +impl ExecuteXcm for () { + type Prepared = Weightless; + fn prepare(message: Xcm) -> result::Result> { + Err(message) + } + fn execute(_: impl Into, _: Self::Prepared, _: &mut XcmHash, _: Weight) -> Outcome { + unreachable!() + } + fn charge_fees(_location: impl Into, _fees: Assets) -> Result { + Err(Error::Unimplemented) + } +} + +pub trait Reanchorable: Sized { + /// Type to return in case of an error. + type Error: Debug; + + /// Mutate `self` so that it represents the same location from the point of view of `target`. + /// The context of `self` is provided as `context`. + /// + /// Does not modify `self` in case of overflow. + fn reanchor( + &mut self, + target: &Location, + context: &InteriorLocation, + ) -> core::result::Result<(), ()>; + + /// Consume `self` and return a new value representing the same location from the point of view + /// of `target`. The context of `self` is provided as `context`. + /// + /// Returns the original `self` in case of overflow. + fn reanchored( + self, + target: &Location, + context: &InteriorLocation, + ) -> core::result::Result; +} + +/// Result value when attempting to send an XCM message. +pub type SendResult = result::Result<(T, Assets), SendError>; + +/// Utility for sending an XCM message to a given location. +/// +/// These can be amalgamated in tuples to form sophisticated routing systems. In tuple format, each +/// router might return `NotApplicable` to pass the execution to the next sender item. Note that +/// each `NotApplicable` might alter the destination and the XCM message for to the next router. +/// +/// # Example +/// ```rust +/// # use codec::Encode; +/// # use staging_xcm::v5::{prelude::*, Weight}; +/// # use staging_xcm::VersionedXcm; +/// # use std::convert::Infallible; +/// +/// /// A sender that only passes the message through and does nothing. +/// struct Sender1; +/// impl SendXcm for Sender1 { +/// type Ticket = Infallible; +/// fn validate(_: &mut Option, _: &mut Option>) -> SendResult { +/// Err(SendError::NotApplicable) +/// } +/// fn deliver(_: Infallible) -> Result { +/// unreachable!() +/// } +/// } +/// +/// /// A sender that accepts a message that has two junctions, otherwise stops the routing. +/// struct Sender2; +/// impl SendXcm for Sender2 { +/// type Ticket = (); +/// fn validate(destination: &mut Option, message: &mut Option>) -> SendResult<()> { +/// match destination.as_ref().ok_or(SendError::MissingArgument)?.unpack() { +/// (0, [j1, j2]) => Ok(((), Assets::new())), +/// _ => Err(SendError::Unroutable), +/// } +/// } +/// fn deliver(_: ()) -> Result { +/// Ok([0; 32]) +/// } +/// } +/// +/// /// A sender that accepts a message from a parent, passing through otherwise. +/// struct Sender3; +/// impl SendXcm for Sender3 { +/// type Ticket = (); +/// fn validate(destination: &mut Option, message: &mut Option>) -> SendResult<()> { +/// match destination.as_ref().ok_or(SendError::MissingArgument)?.unpack() { +/// (1, []) => Ok(((), Assets::new())), +/// _ => Err(SendError::NotApplicable), +/// } +/// } +/// fn deliver(_: ()) -> Result { +/// Ok([0; 32]) +/// } +/// } +/// +/// // A call to send via XCM. We don't really care about this. +/// # fn main() { +/// let call: Vec = ().encode(); +/// let message = Xcm(vec![Instruction::Transact { +/// origin_kind: OriginKind::Superuser, +/// call: call.into(), +/// }]); +/// let message_hash = message.using_encoded(sp_io::hashing::blake2_256); +/// +/// // Sender2 will block this. +/// assert!(send_xcm::<(Sender1, Sender2, Sender3)>(Parent.into(), message.clone()).is_err()); +/// +/// // Sender3 will catch this. +/// assert!(send_xcm::<(Sender1, Sender3)>(Parent.into(), message.clone()).is_ok()); +/// # } +/// ``` +pub trait SendXcm { + /// Intermediate value which connects the two phases of the send operation. + type Ticket; + + /// Check whether the given `_message` is deliverable to the given `_destination` and if so + /// determine the cost which will be paid by this chain to do so, returning a `Validated` token + /// which can be used to enact delivery. + /// + /// The `destination` and `message` must be `Some` (or else an error will be returned) and they + /// may only be consumed if the `Err` is not `NotApplicable`. + /// + /// If it is not a destination which can be reached with this type but possibly could by others, + /// then this *MUST* return `NotApplicable`. Any other error will cause the tuple + /// implementation to exit early without trying other type fields. + fn validate( + destination: &mut Option, + message: &mut Option>, + ) -> SendResult; + + /// Actually carry out the delivery operation for a previously validated message sending. + fn deliver(ticket: Self::Ticket) -> result::Result; +} + +#[impl_trait_for_tuples::impl_for_tuples(30)] +impl SendXcm for Tuple { + for_tuples! { type Ticket = (#( Option ),* ); } + + fn validate( + destination: &mut Option, + message: &mut Option>, + ) -> SendResult { + let mut maybe_cost: Option = None; + let one_ticket: Self::Ticket = (for_tuples! { #( + if maybe_cost.is_some() { + None + } else { + match Tuple::validate(destination, message) { + Err(SendError::NotApplicable) => None, + Err(e) => { return Err(e) }, + Ok((v, c)) => { + maybe_cost = Some(c); + Some(v) + }, + } + } + ),* }); + if let Some(cost) = maybe_cost { + Ok((one_ticket, cost)) + } else { + Err(SendError::NotApplicable) + } + } + + fn deliver(one_ticket: Self::Ticket) -> result::Result { + for_tuples!( #( + if let Some(validated) = one_ticket.Tuple { + return Tuple::deliver(validated); + } + )* ); + Err(SendError::Unroutable) + } +} + +/// Convenience function for using a `SendXcm` implementation. Just interprets the `dest` and wraps +/// both in `Some` before passing them as mutable references into `T::send_xcm`. +pub fn validate_send(dest: Location, msg: Xcm<()>) -> SendResult { + T::validate(&mut Some(dest), &mut Some(msg)) +} + +/// Convenience function for using a `SendXcm` implementation. Just interprets the `dest` and wraps +/// both in `Some` before passing them as mutable references into `T::send_xcm`. +/// +/// Returns either `Ok` with the price of the delivery, or `Err` with the reason why the message +/// could not be sent. +/// +/// Generally you'll want to validate and get the price first to ensure that the sender can pay it +/// before actually doing the delivery. +pub fn send_xcm( + dest: Location, + msg: Xcm<()>, +) -> result::Result<(XcmHash, Assets), SendError> { + let (ticket, price) = T::validate(&mut Some(dest), &mut Some(msg))?; + let hash = T::deliver(ticket)?; + Ok((hash, price)) +} diff --git a/polkadot/xcm/xcm-builder/src/universal_exports.rs b/polkadot/xcm/xcm-builder/src/universal_exports.rs index 5c754f01ec0a..aae8438c78d2 100644 --- a/polkadot/xcm/xcm-builder/src/universal_exports.rs +++ b/polkadot/xcm/xcm-builder/src/universal_exports.rs @@ -68,20 +68,28 @@ impl> SendXcm fn validate( dest: &mut Option, - xcm: &mut Option>, + msg: &mut Option>, ) -> SendResult { - let d = dest.take().ok_or(MissingArgument)?; + // This `clone` ensures that `dest` is not consumed in any case. + let d = dest.clone().take().ok_or(MissingArgument)?; let universal_source = UniversalLocation::get(); - let devolved = match ensure_is_remote(universal_source.clone(), d) { - Ok(x) => x, - Err(d) => { - *dest = Some(d); - return Err(NotApplicable) - }, - }; - let (network, destination) = devolved; - let xcm = xcm.take().ok_or(SendError::MissingArgument)?; - validate_export::(network, 0, universal_source, destination, xcm) + let devolved = ensure_is_remote(universal_source.clone(), d).map_err(|_| NotApplicable)?; + let (remote_network, remote_location) = devolved; + let xcm = msg.take().ok_or(MissingArgument)?; + + validate_export::( + remote_network, + 0, + universal_source, + remote_location, + xcm.clone(), + ) + .inspect_err(|err| { + if let NotApplicable = err { + // We need to make sure that msg is not consumed in case of `NotApplicable`. + *msg = Some(xcm); + } + }) } fn deliver(ticket: Exporter::Ticket) -> Result { @@ -95,7 +103,7 @@ pub trait ExporterFor { /// /// The payment is specified from the local context, not the bridge chain. This is the /// total amount to withdraw in to Holding and should cover both payment for the execution on - /// the bridge chain as well as payment for the use of the `ExportMessage` instruction. + /// the bridge chain and payment for the use of the `ExportMessage` instruction. fn exporter_for( network: &NetworkId, remote_location: &InteriorLocation, @@ -205,7 +213,8 @@ impl, msg: &mut Option>, ) -> SendResult { - let d = dest.clone().ok_or(MissingArgument)?; + // This `clone` ensures that `dest` is not consumed in any case. + let d = dest.clone().take().ok_or(MissingArgument)?; let devolved = ensure_is_remote(UniversalLocation::get(), d).map_err(|_| NotApplicable)?; let (remote_network, remote_location) = devolved; let xcm = msg.take().ok_or(MissingArgument)?; @@ -216,7 +225,7 @@ impl(bridge, message) + validate_send::(bridge, message).inspect_err(|err| { + if let NotApplicable = err { + // We need to make sure that msg is not consumed in case of `NotApplicable`. + *msg = Some(xcm); + } + }) } fn deliver(validation: Self::Ticket) -> Result { @@ -272,9 +290,9 @@ impl, msg: &mut Option>, ) -> SendResult { - let d = dest.as_ref().ok_or(MissingArgument)?; - let devolved = - ensure_is_remote(UniversalLocation::get(), d.clone()).map_err(|_| NotApplicable)?; + // This `clone` ensures that `dest` is not consumed in any case. + let d = dest.clone().take().ok_or(MissingArgument)?; + let devolved = ensure_is_remote(UniversalLocation::get(), d).map_err(|_| NotApplicable)?; let (remote_network, remote_location) = devolved; let xcm = msg.take().ok_or(MissingArgument)?; @@ -284,7 +302,7 @@ impl(bridge, message)?; + let (v, mut cost) = validate_send::(bridge, message).inspect_err(|err| { + if let NotApplicable = err { + // We need to make sure that msg is not consumed in case of `NotApplicable`. + *msg = Some(xcm); + } + })?; if let Some(bridge_payment) = maybe_payment { cost.push(bridge_payment); } @@ -476,10 +502,10 @@ impl< let Location { parents, interior: mut junctions } = BridgedNetwork::get(); match junctions.take_first() { Some(GlobalConsensus(network)) => (network, parents), - _ => return Err(SendError::NotApplicable), + _ => return Err(NotApplicable), } }; - ensure!(&network == &bridged_network, SendError::NotApplicable); + ensure!(&network == &bridged_network, NotApplicable); // We don't/can't use the `channel` for this adapter. let dest = destination.take().ok_or(SendError::MissingArgument)?; @@ -496,7 +522,7 @@ impl< }, Err((dest, _)) => { *destination = Some(dest); - return Err(SendError::NotApplicable) + return Err(NotApplicable) }, }; @@ -540,6 +566,10 @@ impl< #[cfg(test)] mod tests { use super::*; + use frame_support::{ + assert_err, assert_ok, + traits::{Contains, Equals}, + }; #[test] fn ensure_is_remote_works() { @@ -564,21 +594,48 @@ mod tests { assert_eq!(x, Err((Parent, Polkadot, Parachain(1000)).into())); } - pub struct OkSender; - impl SendXcm for OkSender { + pub struct OkFor(PhantomData); + impl> SendXcm for OkFor { type Ticket = (); fn validate( - _destination: &mut Option, + destination: &mut Option, _message: &mut Option>, ) -> SendResult { - Ok(((), Assets::new())) + if let Some(d) = destination.as_ref() { + if Filter::contains(&d) { + return Ok(((), Assets::new())) + } + } + Err(NotApplicable) } fn deliver(_ticket: Self::Ticket) -> Result { Ok([0; 32]) } } + impl> ExportXcm for OkFor { + type Ticket = (); + + fn validate( + network: NetworkId, + _: u32, + _: &mut Option, + destination: &mut Option, + _: &mut Option>, + ) -> SendResult { + if let Some(d) = destination.as_ref() { + if Filter::contains(&(network, d.clone())) { + return Ok(((), Assets::new())) + } + } + Err(NotApplicable) + } + + fn deliver(_ticket: Self::Ticket) -> Result { + Ok([1; 32]) + } + } /// Generic test case asserting that dest and msg is not consumed by `validate` implementation /// of `SendXcm` in case of expected result. @@ -598,46 +655,168 @@ mod tests { } #[test] - fn remote_exporters_does_not_consume_dest_or_msg_on_not_applicable() { + fn local_exporters_works() { frame_support::parameter_types! { pub Local: NetworkId = ByGenesis([0; 32]); pub UniversalLocation: InteriorLocation = [GlobalConsensus(Local::get()), Parachain(1234)].into(); pub DifferentRemote: NetworkId = ByGenesis([22; 32]); - // no routers - pub BridgeTable: Vec = vec![]; + pub RemoteDestination: Junction = Parachain(9657); + pub RoutableBridgeFilter: (NetworkId, InteriorLocation) = (DifferentRemote::get(), RemoteDestination::get().into()); } + type RoutableBridgeExporter = OkFor>; + type NotApplicableBridgeExporter = OkFor<()>; + assert_ok!(validate_export::( + DifferentRemote::get(), + 0, + UniversalLocation::get(), + RemoteDestination::get().into(), + Xcm::default() + )); + assert_err!( + validate_export::( + DifferentRemote::get(), + 0, + UniversalLocation::get(), + RemoteDestination::get().into(), + Xcm::default() + ), + NotApplicable + ); - // check with local destination (should be remote) + // 1. check with local destination (should be remote) let local_dest: Location = (Parent, Parachain(5678)).into(); assert!(ensure_is_remote(UniversalLocation::get(), local_dest.clone()).is_err()); + // UnpaidLocalExporter ensure_validate_does_not_consume_dest_or_msg::< - UnpaidRemoteExporter, OkSender, UniversalLocation>, + UnpaidLocalExporter, >(local_dest.clone(), |result| assert_eq!(Err(NotApplicable), result)); + // 2. check with not applicable from the inner router (using `NotApplicableBridgeSender`) + let remote_dest: Location = + (Parent, Parent, DifferentRemote::get(), RemoteDestination::get()).into(); + assert!(ensure_is_remote(UniversalLocation::get(), remote_dest.clone()).is_ok()); + + // UnpaidLocalExporter + ensure_validate_does_not_consume_dest_or_msg::< + UnpaidLocalExporter, + >(remote_dest.clone(), |result| assert_eq!(Err(NotApplicable), result)); + + // 3. Ok - deliver + // UnpaidRemoteExporter + assert_ok!(send_xcm::>( + remote_dest, + Xcm::default() + )); + } + + #[test] + fn remote_exporters_works() { + frame_support::parameter_types! { + pub Local: NetworkId = ByGenesis([0; 32]); + pub UniversalLocation: InteriorLocation = [GlobalConsensus(Local::get()), Parachain(1234)].into(); + pub DifferentRemote: NetworkId = ByGenesis([22; 32]); + pub RoutableBridge: Location = Location::new(1, Parachain(9657)); + // not routable + pub NotApplicableBridgeTable: Vec = vec![]; + // routable + pub RoutableBridgeTable: Vec = vec![ + NetworkExportTableItem::new( + DifferentRemote::get(), + None, + RoutableBridge::get(), + None + ) + ]; + } + type RoutableBridgeSender = OkFor>; + type NotApplicableBridgeSender = OkFor<()>; + assert_ok!(validate_send::(RoutableBridge::get(), Xcm::default())); + assert_err!( + validate_send::(RoutableBridge::get(), Xcm::default()), + NotApplicable + ); + + // 1. check with local destination (should be remote) + let local_dest: Location = (Parent, Parachain(5678)).into(); + assert!(ensure_is_remote(UniversalLocation::get(), local_dest.clone()).is_err()); + + // UnpaidRemoteExporter + ensure_validate_does_not_consume_dest_or_msg::< + UnpaidRemoteExporter< + NetworkExportTable, + RoutableBridgeSender, + UniversalLocation, + >, + >(local_dest.clone(), |result| assert_eq!(Err(NotApplicable), result)); + // SovereignPaidRemoteExporter ensure_validate_does_not_consume_dest_or_msg::< SovereignPaidRemoteExporter< - NetworkExportTable, - OkSender, + NetworkExportTable, + RoutableBridgeSender, UniversalLocation, >, >(local_dest, |result| assert_eq!(Err(NotApplicable), result)); - // check with not applicable destination + // 2. check with not applicable destination (`NotApplicableBridgeTable`) let remote_dest: Location = (Parent, Parent, DifferentRemote::get()).into(); assert!(ensure_is_remote(UniversalLocation::get(), remote_dest.clone()).is_ok()); + // UnpaidRemoteExporter ensure_validate_does_not_consume_dest_or_msg::< - UnpaidRemoteExporter, OkSender, UniversalLocation>, + UnpaidRemoteExporter< + NetworkExportTable, + RoutableBridgeSender, + UniversalLocation, + >, >(remote_dest.clone(), |result| assert_eq!(Err(NotApplicable), result)); - + // SovereignPaidRemoteExporter ensure_validate_does_not_consume_dest_or_msg::< SovereignPaidRemoteExporter< - NetworkExportTable, - OkSender, + NetworkExportTable, + RoutableBridgeSender, UniversalLocation, >, >(remote_dest, |result| assert_eq!(Err(NotApplicable), result)); + + // 3. check with not applicable from the inner router (using `NotApplicableBridgeSender`) + let remote_dest: Location = (Parent, Parent, DifferentRemote::get()).into(); + assert!(ensure_is_remote(UniversalLocation::get(), remote_dest.clone()).is_ok()); + + // UnpaidRemoteExporter + ensure_validate_does_not_consume_dest_or_msg::< + UnpaidRemoteExporter< + NetworkExportTable, + NotApplicableBridgeSender, + UniversalLocation, + >, + >(remote_dest.clone(), |result| assert_eq!(Err(NotApplicable), result)); + // SovereignPaidRemoteExporter + ensure_validate_does_not_consume_dest_or_msg::< + SovereignPaidRemoteExporter< + NetworkExportTable, + NotApplicableBridgeSender, + UniversalLocation, + >, + >(remote_dest.clone(), |result| assert_eq!(Err(NotApplicable), result)); + + // 4. Ok - deliver + // UnpaidRemoteExporter + assert_ok!(send_xcm::< + UnpaidRemoteExporter< + NetworkExportTable, + RoutableBridgeSender, + UniversalLocation, + >, + >(remote_dest.clone(), Xcm::default())); + // SovereignPaidRemoteExporter + assert_ok!(send_xcm::< + SovereignPaidRemoteExporter< + NetworkExportTable, + RoutableBridgeSender, + UniversalLocation, + >, + >(remote_dest, Xcm::default())); } #[test] diff --git a/polkadot/xcm/xcm-executor/src/traits/export.rs b/polkadot/xcm/xcm-executor/src/traits/export.rs index b356e0da7df7..3e9275edab37 100644 --- a/polkadot/xcm/xcm-executor/src/traits/export.rs +++ b/polkadot/xcm/xcm-executor/src/traits/export.rs @@ -108,7 +108,7 @@ impl ExportXcm for Tuple { } /// Convenience function for using a `SendXcm` implementation. Just interprets the `dest` and wraps -/// both in `Some` before passing them as as mutable references into `T::send_xcm`. +/// both in `Some` before passing them as mutable references into `T::send_xcm`. pub fn validate_export( network: NetworkId, channel: u32, @@ -120,7 +120,7 @@ pub fn validate_export( } /// Convenience function for using a `SendXcm` implementation. Just interprets the `dest` and wraps -/// both in `Some` before passing them as as mutable references into `T::send_xcm`. +/// both in `Some` before passing them as mutable references into `T::send_xcm`. /// /// Returns either `Ok` with the price of the delivery, or `Err` with the reason why the message /// could not be sent. diff --git a/prdoc/pr_6645.prdoc b/prdoc/pr_6645.prdoc new file mode 100644 index 000000000000..f033cadc0b6e --- /dev/null +++ b/prdoc/pr_6645.prdoc @@ -0,0 +1,14 @@ +title: 'xcm: fix local/remote exports when inner routers return `NotApplicable`' +doc: +- audience: Runtime Dev + description: |- + Resolved a bug in the `local/remote exporters` used for bridging. Previously, they consumed `dest` and `msg` without returning them when inner routers/exporters failed with `NotApplicable`. This PR ensures compliance with the [`SendXcm`](https://github.com/paritytech/polkadot-sdk/blob/master/polkadot/xcm/src/v5/traits.rs#L449-L450) and [`ExportXcm`](https://github.com/paritytech/polkadot-sdk/blob/master/polkadot/xcm/xcm-executor/src/traits/export.rs#L44-L45) traits. +crates: +- name: staging-xcm-builder + bump: patch +- name: polkadot + bump: none +- name: staging-xcm + bump: none +- name: staging-xcm-executor + bump: none diff --git a/substrate/frame/examples/default-config/src/lib.rs b/substrate/frame/examples/default-config/src/lib.rs index ccdcd4968598..f690bffe0998 100644 --- a/substrate/frame/examples/default-config/src/lib.rs +++ b/substrate/frame/examples/default-config/src/lib.rs @@ -62,10 +62,10 @@ pub mod pallet { type OverwrittenDefaultValue: Get; /// An input parameter that relies on `::AccountId`. This can - /// too have a default, as long as as it is present in `frame_system::DefaultConfig`. + /// too have a default, as long as it is present in `frame_system::DefaultConfig`. type CanDeriveDefaultFromSystem: Get; - /// We might chose to declare as one that doesn't have a default, for whatever semantical + /// We might choose to declare as one that doesn't have a default, for whatever semantical /// reason. #[pallet::no_default] type HasNoDefault: Get; From a3ae17f7c384123f9dd44da667938550775a1140 Mon Sep 17 00:00:00 2001 From: Branislav Kontur Date: Wed, 27 Nov 2024 09:59:37 +0100 Subject: [PATCH 2/2] Remove v5 file --- polkadot/xcm/src/v5/traits.rs | 525 ---------------------------------- 1 file changed, 525 deletions(-) delete mode 100644 polkadot/xcm/src/v5/traits.rs diff --git a/polkadot/xcm/src/v5/traits.rs b/polkadot/xcm/src/v5/traits.rs deleted file mode 100644 index dd067b774fcd..000000000000 --- a/polkadot/xcm/src/v5/traits.rs +++ /dev/null @@ -1,525 +0,0 @@ -// Copyright (C) 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 . - -//! Cross-Consensus Message format data structures. - -pub use crate::v3::{Error as OldError, SendError, XcmHash}; -use codec::{Decode, Encode}; -use core::result; -use scale_info::TypeInfo; - -pub use sp_weights::Weight; - -use super::*; - -/// Error codes used in XCM. The first errors codes have explicit indices and are part of the XCM -/// format. Those trailing are merely part of the XCM implementation; there is no expectation that -/// they will retain the same index over time. -#[derive(Copy, Clone, Encode, Decode, Eq, PartialEq, Debug, TypeInfo)] -#[scale_info(replace_segment("staging_xcm", "xcm"))] -#[cfg_attr(feature = "json-schema", derive(schemars::JsonSchema))] -pub enum Error { - // Errors that happen due to instructions being executed. These alone are defined in the - // XCM specification. - /// An arithmetic overflow happened. - #[codec(index = 0)] - Overflow, - /// The instruction is intentionally unsupported. - #[codec(index = 1)] - Unimplemented, - /// Origin Register does not contain a value value for a reserve transfer notification. - #[codec(index = 2)] - UntrustedReserveLocation, - /// Origin Register does not contain a value value for a teleport notification. - #[codec(index = 3)] - UntrustedTeleportLocation, - /// `MultiLocation` value too large to descend further. - #[codec(index = 4)] - LocationFull, - /// `MultiLocation` value ascend more parents than known ancestors of local location. - #[codec(index = 5)] - LocationNotInvertible, - /// The Origin Register does not contain a valid value for instruction. - #[codec(index = 6)] - BadOrigin, - /// The location parameter is not a valid value for the instruction. - #[codec(index = 7)] - InvalidLocation, - /// The given asset is not handled. - #[codec(index = 8)] - AssetNotFound, - /// An asset transaction (like withdraw or deposit) failed (typically due to type conversions). - #[codec(index = 9)] - FailedToTransactAsset(#[codec(skip)] &'static str), - /// An asset cannot be withdrawn, potentially due to lack of ownership, availability or rights. - #[codec(index = 10)] - NotWithdrawable, - /// An asset cannot be deposited under the ownership of a particular location. - #[codec(index = 11)] - LocationCannotHold, - /// Attempt to send a message greater than the maximum supported by the transport protocol. - #[codec(index = 12)] - ExceedsMaxMessageSize, - /// The given message cannot be translated into a format supported by the destination. - #[codec(index = 13)] - DestinationUnsupported, - /// Destination is routable, but there is some issue with the transport mechanism. - #[codec(index = 14)] - Transport(#[codec(skip)] &'static str), - /// Destination is known to be unroutable. - #[codec(index = 15)] - Unroutable, - /// Used by `ClaimAsset` when the given claim could not be recognized/found. - #[codec(index = 16)] - UnknownClaim, - /// Used by `Transact` when the functor cannot be decoded. - #[codec(index = 17)] - FailedToDecode, - /// Used by `Transact` to indicate that the given weight limit could be breached by the - /// functor. - #[codec(index = 18)] - MaxWeightInvalid, - /// Used by `BuyExecution` when the Holding Register does not contain payable fees. - #[codec(index = 19)] - NotHoldingFees, - /// Used by `BuyExecution` when the fees declared to purchase weight are insufficient. - #[codec(index = 20)] - TooExpensive, - /// Used by the `Trap` instruction to force an error intentionally. Its code is included. - #[codec(index = 21)] - Trap(u64), - /// Used by `ExpectAsset`, `ExpectError` and `ExpectOrigin` when the expectation was not true. - #[codec(index = 22)] - ExpectationFalse, - /// The provided pallet index was not found. - #[codec(index = 23)] - PalletNotFound, - /// The given pallet's name is different to that expected. - #[codec(index = 24)] - NameMismatch, - /// The given pallet's version has an incompatible version to that expected. - #[codec(index = 25)] - VersionIncompatible, - /// The given operation would lead to an overflow of the Holding Register. - #[codec(index = 26)] - HoldingWouldOverflow, - /// The message was unable to be exported. - #[codec(index = 27)] - ExportError, - /// `MultiLocation` value failed to be reanchored. - #[codec(index = 28)] - ReanchorFailed, - /// No deal is possible under the given constraints. - #[codec(index = 29)] - NoDeal, - /// Fees were required which the origin could not pay. - #[codec(index = 30)] - FeesNotMet, - /// Some other error with locking. - #[codec(index = 31)] - LockError, - /// The state was not in a condition where the operation was valid to make. - #[codec(index = 32)] - NoPermission, - /// The universal location of the local consensus is improper. - #[codec(index = 33)] - Unanchored, - /// An asset cannot be deposited, probably because (too much of) it already exists. - #[codec(index = 34)] - NotDepositable, - /// Too many assets matched the given asset filter. - #[codec(index = 35)] - TooManyAssets, - - // Errors that happen prior to instructions being executed. These fall outside of the XCM - // spec. - /// XCM version not able to be handled. - UnhandledXcmVersion, - /// Execution of the XCM would potentially result in a greater weight used than weight limit. - WeightLimitReached(Weight), - /// The XCM did not pass the barrier condition for execution. - /// - /// The barrier condition differs on different chains and in different circumstances, but - /// generally it means that the conditions surrounding the message were not such that the chain - /// considers the message worth spending time executing. Since most chains lift the barrier to - /// execution on appropriate payment, presentation of an NFT voucher, or based on the message - /// origin, it means that none of those were the case. - Barrier, - /// The weight of an XCM message is not computable ahead of execution. - WeightNotComputable, - /// Recursion stack limit reached - // TODO(https://github.com/paritytech/polkadot-sdk/issues/6199): This should have a fixed index since - // we use it in `FrameTransactionalProcessor` // which is used in instructions. - // Or we should create a different error for that. - ExceedsStackLimit, -} - -impl TryFrom for Error { - type Error = (); - fn try_from(old_error: OldError) -> result::Result { - use OldError::*; - Ok(match old_error { - Overflow => Self::Overflow, - Unimplemented => Self::Unimplemented, - UntrustedReserveLocation => Self::UntrustedReserveLocation, - UntrustedTeleportLocation => Self::UntrustedTeleportLocation, - LocationFull => Self::LocationFull, - LocationNotInvertible => Self::LocationNotInvertible, - BadOrigin => Self::BadOrigin, - InvalidLocation => Self::InvalidLocation, - AssetNotFound => Self::AssetNotFound, - FailedToTransactAsset(s) => Self::FailedToTransactAsset(s), - NotWithdrawable => Self::NotWithdrawable, - LocationCannotHold => Self::LocationCannotHold, - ExceedsMaxMessageSize => Self::ExceedsMaxMessageSize, - DestinationUnsupported => Self::DestinationUnsupported, - Transport(s) => Self::Transport(s), - Unroutable => Self::Unroutable, - UnknownClaim => Self::UnknownClaim, - FailedToDecode => Self::FailedToDecode, - MaxWeightInvalid => Self::MaxWeightInvalid, - NotHoldingFees => Self::NotHoldingFees, - TooExpensive => Self::TooExpensive, - Trap(i) => Self::Trap(i), - ExpectationFalse => Self::ExpectationFalse, - PalletNotFound => Self::PalletNotFound, - NameMismatch => Self::NameMismatch, - VersionIncompatible => Self::VersionIncompatible, - HoldingWouldOverflow => Self::HoldingWouldOverflow, - ExportError => Self::ExportError, - ReanchorFailed => Self::ReanchorFailed, - NoDeal => Self::NoDeal, - FeesNotMet => Self::FeesNotMet, - LockError => Self::LockError, - NoPermission => Self::NoPermission, - Unanchored => Self::Unanchored, - NotDepositable => Self::NotDepositable, - UnhandledXcmVersion => Self::UnhandledXcmVersion, - WeightLimitReached(weight) => Self::WeightLimitReached(weight), - Barrier => Self::Barrier, - WeightNotComputable => Self::WeightNotComputable, - ExceedsStackLimit => Self::ExceedsStackLimit, - }) - } -} - -impl MaxEncodedLen for Error { - fn max_encoded_len() -> usize { - // TODO: max_encoded_len doesn't quite work here as it tries to take notice of the fields - // marked `codec(skip)`. We can hard-code it with the right answer for now. - 1 - } -} - -impl From for Error { - fn from(e: SendError) -> Self { - match e { - SendError::NotApplicable | SendError::Unroutable | SendError::MissingArgument => - Error::Unroutable, - SendError::Transport(s) => Error::Transport(s), - SendError::DestinationUnsupported => Error::DestinationUnsupported, - SendError::ExceedsMaxMessageSize => Error::ExceedsMaxMessageSize, - SendError::Fees => Error::FeesNotMet, - } - } -} - -pub type Result = result::Result<(), Error>; - -/// Outcome of an XCM execution. -#[derive(Clone, Encode, Decode, Eq, PartialEq, Debug, TypeInfo)] -pub enum Outcome { - /// Execution completed successfully; given weight was used. - Complete { used: Weight }, - /// Execution started, but did not complete successfully due to the given error; given weight - /// was used. - Incomplete { used: Weight, error: Error }, - /// Execution did not start due to the given error. - Error { error: Error }, -} - -impl Outcome { - pub fn ensure_complete(self) -> Result { - match self { - Outcome::Complete { .. } => Ok(()), - Outcome::Incomplete { error, .. } => Err(error), - Outcome::Error { error, .. } => Err(error), - } - } - pub fn ensure_execution(self) -> result::Result { - match self { - Outcome::Complete { used, .. } => Ok(used), - Outcome::Incomplete { used, .. } => Ok(used), - Outcome::Error { error, .. } => Err(error), - } - } - /// How much weight was used by the XCM execution attempt. - pub fn weight_used(&self) -> Weight { - match self { - Outcome::Complete { used, .. } => *used, - Outcome::Incomplete { used, .. } => *used, - Outcome::Error { .. } => Weight::zero(), - } - } -} - -impl From for Outcome { - fn from(error: Error) -> Self { - Self::Error { error } - } -} - -pub trait PreparedMessage { - fn weight_of(&self) -> Weight; -} - -/// Type of XCM message executor. -pub trait ExecuteXcm { - type Prepared: PreparedMessage; - fn prepare(message: Xcm) -> result::Result>; - fn execute( - origin: impl Into, - pre: Self::Prepared, - id: &mut XcmHash, - weight_credit: Weight, - ) -> Outcome; - fn prepare_and_execute( - origin: impl Into, - message: Xcm, - id: &mut XcmHash, - weight_limit: Weight, - weight_credit: Weight, - ) -> Outcome { - let pre = match Self::prepare(message) { - Ok(x) => x, - Err(_) => return Outcome::Error { error: Error::WeightNotComputable }, - }; - let xcm_weight = pre.weight_of(); - if xcm_weight.any_gt(weight_limit) { - return Outcome::Error { error: Error::WeightLimitReached(xcm_weight) } - } - Self::execute(origin, pre, id, weight_credit) - } - - /// Deduct some `fees` to the sovereign account of the given `location` and place them as per - /// the convention for fees. - fn charge_fees(location: impl Into, fees: Assets) -> Result; -} - -pub enum Weightless {} -impl PreparedMessage for Weightless { - fn weight_of(&self) -> Weight { - unreachable!() - } -} - -impl ExecuteXcm for () { - type Prepared = Weightless; - fn prepare(message: Xcm) -> result::Result> { - Err(message) - } - fn execute(_: impl Into, _: Self::Prepared, _: &mut XcmHash, _: Weight) -> Outcome { - unreachable!() - } - fn charge_fees(_location: impl Into, _fees: Assets) -> Result { - Err(Error::Unimplemented) - } -} - -pub trait Reanchorable: Sized { - /// Type to return in case of an error. - type Error: Debug; - - /// Mutate `self` so that it represents the same location from the point of view of `target`. - /// The context of `self` is provided as `context`. - /// - /// Does not modify `self` in case of overflow. - fn reanchor( - &mut self, - target: &Location, - context: &InteriorLocation, - ) -> core::result::Result<(), ()>; - - /// Consume `self` and return a new value representing the same location from the point of view - /// of `target`. The context of `self` is provided as `context`. - /// - /// Returns the original `self` in case of overflow. - fn reanchored( - self, - target: &Location, - context: &InteriorLocation, - ) -> core::result::Result; -} - -/// Result value when attempting to send an XCM message. -pub type SendResult = result::Result<(T, Assets), SendError>; - -/// Utility for sending an XCM message to a given location. -/// -/// These can be amalgamated in tuples to form sophisticated routing systems. In tuple format, each -/// router might return `NotApplicable` to pass the execution to the next sender item. Note that -/// each `NotApplicable` might alter the destination and the XCM message for to the next router. -/// -/// # Example -/// ```rust -/// # use codec::Encode; -/// # use staging_xcm::v5::{prelude::*, Weight}; -/// # use staging_xcm::VersionedXcm; -/// # use std::convert::Infallible; -/// -/// /// A sender that only passes the message through and does nothing. -/// struct Sender1; -/// impl SendXcm for Sender1 { -/// type Ticket = Infallible; -/// fn validate(_: &mut Option, _: &mut Option>) -> SendResult { -/// Err(SendError::NotApplicable) -/// } -/// fn deliver(_: Infallible) -> Result { -/// unreachable!() -/// } -/// } -/// -/// /// A sender that accepts a message that has two junctions, otherwise stops the routing. -/// struct Sender2; -/// impl SendXcm for Sender2 { -/// type Ticket = (); -/// fn validate(destination: &mut Option, message: &mut Option>) -> SendResult<()> { -/// match destination.as_ref().ok_or(SendError::MissingArgument)?.unpack() { -/// (0, [j1, j2]) => Ok(((), Assets::new())), -/// _ => Err(SendError::Unroutable), -/// } -/// } -/// fn deliver(_: ()) -> Result { -/// Ok([0; 32]) -/// } -/// } -/// -/// /// A sender that accepts a message from a parent, passing through otherwise. -/// struct Sender3; -/// impl SendXcm for Sender3 { -/// type Ticket = (); -/// fn validate(destination: &mut Option, message: &mut Option>) -> SendResult<()> { -/// match destination.as_ref().ok_or(SendError::MissingArgument)?.unpack() { -/// (1, []) => Ok(((), Assets::new())), -/// _ => Err(SendError::NotApplicable), -/// } -/// } -/// fn deliver(_: ()) -> Result { -/// Ok([0; 32]) -/// } -/// } -/// -/// // A call to send via XCM. We don't really care about this. -/// # fn main() { -/// let call: Vec = ().encode(); -/// let message = Xcm(vec![Instruction::Transact { -/// origin_kind: OriginKind::Superuser, -/// call: call.into(), -/// }]); -/// let message_hash = message.using_encoded(sp_io::hashing::blake2_256); -/// -/// // Sender2 will block this. -/// assert!(send_xcm::<(Sender1, Sender2, Sender3)>(Parent.into(), message.clone()).is_err()); -/// -/// // Sender3 will catch this. -/// assert!(send_xcm::<(Sender1, Sender3)>(Parent.into(), message.clone()).is_ok()); -/// # } -/// ``` -pub trait SendXcm { - /// Intermediate value which connects the two phases of the send operation. - type Ticket; - - /// Check whether the given `_message` is deliverable to the given `_destination` and if so - /// determine the cost which will be paid by this chain to do so, returning a `Validated` token - /// which can be used to enact delivery. - /// - /// The `destination` and `message` must be `Some` (or else an error will be returned) and they - /// may only be consumed if the `Err` is not `NotApplicable`. - /// - /// If it is not a destination which can be reached with this type but possibly could by others, - /// then this *MUST* return `NotApplicable`. Any other error will cause the tuple - /// implementation to exit early without trying other type fields. - fn validate( - destination: &mut Option, - message: &mut Option>, - ) -> SendResult; - - /// Actually carry out the delivery operation for a previously validated message sending. - fn deliver(ticket: Self::Ticket) -> result::Result; -} - -#[impl_trait_for_tuples::impl_for_tuples(30)] -impl SendXcm for Tuple { - for_tuples! { type Ticket = (#( Option ),* ); } - - fn validate( - destination: &mut Option, - message: &mut Option>, - ) -> SendResult { - let mut maybe_cost: Option = None; - let one_ticket: Self::Ticket = (for_tuples! { #( - if maybe_cost.is_some() { - None - } else { - match Tuple::validate(destination, message) { - Err(SendError::NotApplicable) => None, - Err(e) => { return Err(e) }, - Ok((v, c)) => { - maybe_cost = Some(c); - Some(v) - }, - } - } - ),* }); - if let Some(cost) = maybe_cost { - Ok((one_ticket, cost)) - } else { - Err(SendError::NotApplicable) - } - } - - fn deliver(one_ticket: Self::Ticket) -> result::Result { - for_tuples!( #( - if let Some(validated) = one_ticket.Tuple { - return Tuple::deliver(validated); - } - )* ); - Err(SendError::Unroutable) - } -} - -/// Convenience function for using a `SendXcm` implementation. Just interprets the `dest` and wraps -/// both in `Some` before passing them as mutable references into `T::send_xcm`. -pub fn validate_send(dest: Location, msg: Xcm<()>) -> SendResult { - T::validate(&mut Some(dest), &mut Some(msg)) -} - -/// Convenience function for using a `SendXcm` implementation. Just interprets the `dest` and wraps -/// both in `Some` before passing them as mutable references into `T::send_xcm`. -/// -/// Returns either `Ok` with the price of the delivery, or `Err` with the reason why the message -/// could not be sent. -/// -/// Generally you'll want to validate and get the price first to ensure that the sender can pay it -/// before actually doing the delivery. -pub fn send_xcm( - dest: Location, - msg: Xcm<()>, -) -> result::Result<(XcmHash, Assets), SendError> { - let (ticket, price) = T::validate(&mut Some(dest), &mut Some(msg))?; - let hash = T::deliver(ticket)?; - Ok((hash, price)) -}