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Outline of the transaction-chaining scheduler

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This commit is contained in:
Luke Parker
2024-09-01 01:55:04 -04:00
parent 6deb60513c
commit c88ebe985e
13 changed files with 321 additions and 72 deletions
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50
processor/scheduler/utxo/primitives/src/lib.rs
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@@ -6,12 +6,12 @@ use core::fmt::Debug;
use serai_primitives::{Coin, Amount};
use primitives::ReceivedOutput;
use scanner::{Payment, ScannerFeed, AddressFor, OutputFor};
use primitives::{ReceivedOutput, Payment};
use scanner::{ScannerFeed, KeyFor, AddressFor, OutputFor};
/// An object able to plan a transaction.
#[async_trait::async_trait]
pub trait TransactionPlanner<S: ScannerFeed> {
pub trait TransactionPlanner<S: ScannerFeed>: 'static + Send + Sync {
/// An error encountered when determining the fee rate.
///
/// This MUST be an ephemeral error. Retrying fetching data from the blockchain MUST eventually
@@ -33,17 +33,22 @@ pub trait TransactionPlanner<S: ScannerFeed> {
coin: Coin,
) -> Result<Self::FeeRate, Self::EphemeralError>;
/// The branch address for this key of Serai's.
fn branch_address(key: KeyFor<S>) -> AddressFor<S>;
/// The change address for this key of Serai's.
fn change_address(key: KeyFor<S>) -> AddressFor<S>;
/// The forwarding address for this key of Serai's.
fn forwarding_address(key: KeyFor<S>) -> AddressFor<S>;
/// Calculate the for a tansaction with this structure.
///
/// The fee rate, inputs, and payments, will all be for the same coin. The returned fee is
/// denominated in this coin.
fn calculate_fee(
&self,
block_number: u64,
fee_rate: Self::FeeRate,
inputs: Vec<OutputFor<S>>,
payments: Vec<Payment<S>>,
change: Option<AddressFor<S>>,
payments: Vec<Payment<AddressFor<S>>>,
change: Option<KeyFor<S>>,
) -> Amount;
/// Plan a transaction.
@@ -53,12 +58,10 @@ pub trait TransactionPlanner<S: ScannerFeed> {
///
/// `change` will always be an address belonging to the Serai network.
fn plan(
&self,
block_number: u64,
fee_rate: Self::FeeRate,
inputs: Vec<OutputFor<S>>,
payments: Vec<Payment<S>>,
change: Option<AddressFor<S>>,
payments: Vec<Payment<AddressFor<S>>>,
change: Option<KeyFor<S>>,
) -> Self::PlannedTransaction;
/// Obtain a PlannedTransaction via amortizing the fee over the payments.
@@ -69,13 +72,11 @@ pub trait TransactionPlanner<S: ScannerFeed> {
///
/// Returns `None` if the fee exceeded the inputs, or `Some` otherwise.
fn plan_transaction_with_fee_amortization(
&self,
operating_costs: &mut u64,
block_number: u64,
fee_rate: Self::FeeRate,
inputs: Vec<OutputFor<S>>,
mut payments: Vec<Payment<S>>,
change: Option<AddressFor<S>>,
mut payments: Vec<Payment<AddressFor<S>>>,
mut change: Option<KeyFor<S>>,
) -> Option<Self::PlannedTransaction> {
// Sanity checks
{
@@ -102,9 +103,7 @@ pub trait TransactionPlanner<S: ScannerFeed> {
// Sort payments from high amount to low amount
payments.sort_by(|a, b| a.balance().amount.0.cmp(&b.balance().amount.0).reverse());
let mut fee = self
.calculate_fee(block_number, fee_rate, inputs.clone(), payments.clone(), change.clone())
.0;
let mut fee = Self::calculate_fee(fee_rate, inputs.clone(), payments.clone(), change).0;
let mut amortized = 0;
while !payments.is_empty() {
// We need to pay the fee, and any accrued operating costs, minus what we've already
@@ -124,9 +123,7 @@ pub trait TransactionPlanner<S: ScannerFeed> {
if payments.last().unwrap().balance().amount.0 <= (per_payment_fee + S::dust(coin).0) {
amortized += payments.pop().unwrap().balance().amount.0;
// Recalculate the fee and try again
fee = self
.calculate_fee(block_number, fee_rate, inputs.clone(), payments.clone(), change.clone())
.0;
fee = Self::calculate_fee(fee_rate, inputs.clone(), payments.clone(), change).0;
continue;
}
// Break since all of these payments shouldn't be dropped
@@ -167,6 +164,15 @@ pub trait TransactionPlanner<S: ScannerFeed> {
amortized += per_payment_fee;
}
assert!(amortized >= (*operating_costs + fee));
// If the change is less than the dust, drop it
let would_be_change = inputs.iter().map(|input| input.balance().amount.0).sum::<u64>() -
payments.iter().map(|payment| payment.balance().amount.0).sum::<u64>() -
fee;
if would_be_change < S::dust(coin).0 {
change = None;
*operating_costs += would_be_change;
}
}
// Update the amount of operating costs
@@ -174,6 +180,6 @@ pub trait TransactionPlanner<S: ScannerFeed> {
}
// Because we amortized, or accrued as operating costs, the fee, make the transaction
Some(self.plan(block_number, fee_rate, inputs, payments, change))
Some(Self::plan(fee_rate, inputs, payments, change))
}
}