, SubstrateError> {
// we can't continue to deliver messages if target node is out of sync, because
// it may have already received (some of) messages that we're going to deliver
self.client.ensure_synced().await?;
read_client_state::<_, P::SourceHeaderHash, P::SourceHeaderNumber>(
&self.client,
P::BEST_FINALIZED_SOURCE_HEADER_ID_AT_TARGET,
)
.await
}
async fn latest_received_nonce(
&self,
id: TargetHeaderIdOf,
) -> Result<(TargetHeaderIdOf
, MessageNonce), SubstrateError> {
let encoded_response = self
.client
.state_call(
P::INBOUND_LANE_LATEST_RECEIVED_NONCE_METHOD.into(),
Bytes(self.lane_id.encode()),
Some(id.1),
)
.await?;
let latest_received_nonce: MessageNonce =
Decode::decode(&mut &encoded_response.0[..]).map_err(SubstrateError::ResponseParseFailed)?;
Ok((id, latest_received_nonce))
}
async fn latest_confirmed_received_nonce(
&self,
id: TargetHeaderIdOf
,
) -> Result<(TargetHeaderIdOf
, MessageNonce), SubstrateError> {
let encoded_response = self
.client
.state_call(
P::INBOUND_LANE_LATEST_CONFIRMED_NONCE_METHOD.into(),
Bytes(self.lane_id.encode()),
Some(id.1),
)
.await?;
let latest_received_nonce: MessageNonce =
Decode::decode(&mut &encoded_response.0[..]).map_err(SubstrateError::ResponseParseFailed)?;
Ok((id, latest_received_nonce))
}
async fn unrewarded_relayers_state(
&self,
id: TargetHeaderIdOf
,
) -> Result<(TargetHeaderIdOf
, UnrewardedRelayersState), SubstrateError> {
let encoded_response = self
.client
.state_call(
P::INBOUND_LANE_UNREWARDED_RELAYERS_STATE.into(),
Bytes(self.lane_id.encode()),
Some(id.1),
)
.await?;
let unrewarded_relayers_state: UnrewardedRelayersState =
Decode::decode(&mut &encoded_response.0[..]).map_err(SubstrateError::ResponseParseFailed)?;
Ok((id, unrewarded_relayers_state))
}
async fn prove_messages_receiving(
&self,
id: TargetHeaderIdOf
,
) -> Result<(TargetHeaderIdOf
, P::MessagesReceivingProof), SubstrateError> {
let (id, relayers_state) = self.unrewarded_relayers_state(id).await?;
let inbound_data_key = pallet_bridge_messages::storage_keys::inbound_lane_data_key::(&self.lane_id);
let proof = self
.client
.prove_storage(vec![inbound_data_key], id.1)
.await?
.iter_nodes()
.collect();
let proof = FromBridgedChainMessagesDeliveryProof {
bridged_header_hash: id.1,
storage_proof: proof,
lane: self.lane_id,
};
Ok((id, (relayers_state, proof)))
}
async fn submit_messages_proof(
&self,
generated_at_header: SourceHeaderIdOf
,
nonces: RangeInclusive,
proof: P::MessagesProof,
) -> Result, SubstrateError> {
self.client
.submit_signed_extrinsic(self.lane.target_transactions_author(), |transaction_nonce| {
self.lane.make_messages_delivery_transaction(
transaction_nonce,
generated_at_header,
nonces.clone(),
proof,
)
})
.await?;
Ok(nonces)
}
async fn require_source_header_on_target(&self, id: SourceHeaderIdOf) {
if let Some(ref source_to_target_headers_relay) = self.source_to_target_headers_relay {
source_to_target_headers_relay.require_finalized_header(id).await;
}
}
async fn estimate_delivery_transaction_in_source_tokens(
&self,
nonces: RangeInclusive,
total_dispatch_weight: Weight,
total_size: u32,
) -> P::SourceChainBalance {
// TODO: use actual rate (https://github.com/paritytech/parity-bridges-common/issues/997)
convert_target_tokens_to_source_tokens::(
FixedU128::one(),
self.client
.estimate_extrinsic_fee(self.lane.make_messages_delivery_transaction(
Zero::zero(),
HeaderId(Default::default(), Default::default()),
nonces.clone(),
prepare_dummy_messages_proof::(nonces, total_dispatch_weight, total_size),
))
.await
.unwrap_or_else(|_| TC::Balance::max_value()),
)
}
}
/// Prepare 'dummy' messages proof that will compose the delivery transaction.
///
/// We don't care about proof actually being the valid proof, because its validity doesn't
/// affect the call weight - we only care about its size.
fn prepare_dummy_messages_proof(
nonces: RangeInclusive,
total_dispatch_weight: Weight,
total_size: u32,
) -> SubstrateMessagesProof {
(
total_dispatch_weight,
FromBridgedChainMessagesProof {
bridged_header_hash: Default::default(),
storage_proof: vec![vec![0; SC::STORAGE_PROOF_OVERHEAD.saturating_add(total_size) as usize]],
lane: Default::default(),
nonces_start: *nonces.start(),
nonces_end: *nonces.end(),
},
)
}
/// Given delivery transaction fee in target chain tokens and conversion rate to the source
/// chain tokens, compute transaction cost in source chain tokens.
fn convert_target_tokens_to_source_tokens(
target_to_source_conversion_rate: FixedU128,
target_transaction_fee: TC::Balance,
) -> SC::Balance
where
SC::Balance: TryFrom,
{
SC::Balance::try_from(target_to_source_conversion_rate.saturating_mul_int(target_transaction_fee))
.unwrap_or_else(|_| SC::Balance::max_value())
}
#[cfg(test)]
mod tests {
use super::*;
use relay_millau_client::Millau;
use relay_rialto_client::Rialto;
#[test]
fn prepare_dummy_messages_proof_works() {
const DISPATCH_WEIGHT: Weight = 1_000_000;
const SIZE: u32 = 1_000;
let dummy_proof = prepare_dummy_messages_proof::(1..=10, DISPATCH_WEIGHT, SIZE);
assert_eq!(dummy_proof.0, DISPATCH_WEIGHT);
assert!(
dummy_proof.1.encode().len() as u32 > SIZE,
"Expected proof size at least {}. Got: {}",
SIZE,
dummy_proof.1.encode().len(),
);
}
#[test]
fn convert_target_tokens_to_source_tokens_works() {
assert_eq!(
convert_target_tokens_to_source_tokens::((150, 100).into(), 1_000),
1_500
);
assert_eq!(
convert_target_tokens_to_source_tokens::((50, 100).into(), 1_000),
500
);
assert_eq!(
convert_target_tokens_to_source_tokens::((100, 100).into(), 1_000),
1_000
);
}
}