Trait xcm_executor::traits::ExportXcm
source · pub trait ExportXcm {
type Ticket;
// Required methods
fn validate(
network: NetworkId,
channel: u32,
universal_source: &mut Option<InteriorMultiLocation>,
destination: &mut Option<InteriorMultiLocation>,
message: &mut Option<Xcm<()>>
) -> SendResult<Self::Ticket>;
fn deliver(ticket: Self::Ticket) -> Result<XcmHash, SendError>;
}Expand description
Utility for delivering a message to a system under a different (non-local) consensus with a
spoofed origin. This essentially defines the behaviour of the ExportMessage XCM instruction.
This is quite different to SendXcm; SendXcm assumes that the local side’s location will be
preserved to be represented as the value of the Origin register in the messages execution.
This trait on the other hand assumes that we do not necessarily want the Origin register to contain the local (i.e. the caller chain’s) location, since it will generally be exporting a message on behalf of another consensus system. Therefore in addition to the message, the destination must be given in two parts: the network and the interior location within it.
We also require the caller to state exactly what location they purport to be representing. The destination must accept the local location to represent that location or the operation will fail.
Required Associated Types§
Required Methods§
sourcefn validate(
network: NetworkId,
channel: u32,
universal_source: &mut Option<InteriorMultiLocation>,
destination: &mut Option<InteriorMultiLocation>,
message: &mut Option<Xcm<()>>
) -> SendResult<Self::Ticket>
fn validate( network: NetworkId, channel: u32, universal_source: &mut Option<InteriorMultiLocation>, destination: &mut Option<InteriorMultiLocation>, message: &mut Option<Xcm<()>> ) -> SendResult<Self::Ticket>
Check whether the given message is deliverable to the given destination on network,
spoofing its source as universal_source and if so determine the cost which will be paid by
this chain to do so, returning a Ticket token which can be used to enact delivery.
The channel to be used on the network’s export mechanism (bridge, probably) must also
be provided.
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 (used to compose routing systems from different delivery agents) to exit
early without trying alternative means of delivery.
sourcefn deliver(ticket: Self::Ticket) -> Result<XcmHash, SendError>
fn deliver(ticket: Self::Ticket) -> Result<XcmHash, SendError>
Actually carry out the delivery operation for a previously validated message sending.
The implementation should do everything possible to ensure that this function is infallible
if called immediately after validate. Returning an error here would result in a price
paid without the service being delivered.