Module xcm::v2

XCM Version 2

Version 2 of the Cross-Consensus Message format data structures. The comprehensive list of changes can be found in this PR description.

Changes to be aware of

The biggest change here is the restructuring of XCM messages: instead of having Order and Xcm types, the Xcm type now simply wraps a Vec containing Instructions. However, most changes should still be automatically convertible via the try_from and from conversion functions.

Junction

• No special attention necessary

MultiLocation

• No special attention necessary

MultiAsset

• No special attention necessary

XCM and Order

• Xcm and Order variants are now combined under a single Instruction enum.
• Order is now obsolete and replaced entirely by Instruction.
• Xcm is now a simple wrapper around a Vec<Instruction>.
• During conversion from Order to Instruction, we do not handle BuyExecutions that have nested XCMs, i.e. if the instructions field in the BuyExecution enum struct variant is not empty, then the conversion will fail. To address this, rewrite the XCM using Instructions in chronological order.
• During conversion from Xcm to Instruction, we do not handle RelayedFrom messages at all.

XCM Pallet

• The Weigher configuration item must have sensible weights defined for BuyExecution and DepositAsset instructions. Failing that, dispatch calls to teleport_assets and reserve_transfer_assets will fail with UnweighableMessage.

Re-exports

pub use super::v1::OriginKind;

Modules

opaque

prelude

A prelude for importing all types typically used when interacting with XCM messages.

Structs

Ancestor

A unit struct which can be converted into a MultiLocation of the inner parents value.

AncestorThen

A unit struct which can be converted into a MultiLocation of the inner parents value and the inner interior.

MultiAsset

MultiAssets

A Vec of MultiAssets. There may be no duplicate fungible items in here and when decoding, they must be sorted.

MultiLocation

A relative path between state-bearing consensus systems.

Parent

A unit struct which can be converted into a MultiLocation of parents value 1.

ParentThen

A tuple struct which can be converted into a MultiLocation of parents value 1 with the inner interior.

Xcm

Enums

AssetId

Classification of an asset being concrete or abstract.

AssetInstance

A general identifier for an instance of a non-fungible asset class.

BodyId

An identifier of a pluralistic body.

BodyPart

A part of a pluralistic body.

Error

Fungibility

Classification of whether an asset is fungible or not, along with a mandatory amount or instance.

Instruction

Cross-Consensus Message: A message from one consensus system to another.

Junction

A single item in a path to describe the relative location of a consensus system.

Junctions

Non-parent junctions that can be constructed, up to the length of 8. This specific Junctions implementation uses a Rust enum in order to make pattern matching easier.

MultiAssetFilter

MultiAsset collection, either MultiAssets or a single wildcard.

NetworkId

A global identifier of an account-bearing consensus system.

Outcome

Outcome of an XCM execution.

Response

Response data to a query.

SendError

Error result value when attempting to send an XCM message.

WeightLimit

An optional weight limit.

WildFungibility

Classification of whether an asset is fungible or not.

WildMultiAsset

A wildcard representing a set of assets.

Constants

VERSION

This module’s XCM version.

Traits

ExecuteXcm

Type of XCM message executor.

SendXcm

Utility for sending an XCM message.

XcmWeightInfo

Type Definitions

InteriorMultiLocation

A relative location which is constrained to be an interior location of the context.

QueryId

An identifier for a query.

Result

SendResult

Result value when attempting to send an XCM message.

Weight

Local weight type; execution time in picoseconds.