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Correct input/output selection

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Payments weren't properly selected, as it'd drain a sequential series 
instead of the specified set, and inputs had a memory condition Rust 
couldn't prove was safe.
This commit is contained in:
Luke Parker 2022-06-09 04:34:15 -04:00
parent d611300adb
commit 75fb9b3198
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GPG key ID: F9F1386DB1E119B6
1 changed files with 18 additions and 14 deletions
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32
processor/src/wallet.rs
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@ -207,20 +207,23 @@ impl<D: CoinDb, C: Coin> Wallet<D, C> {
while outputs.len() != 0 {
// Select the maximum amount of outputs possible
let mut inputs = &outputs[0 .. C::MAX_INPUTS.min(outputs.len())];
let mut input_bound = C::MAX_INPUTS.min(outputs.len());
// Calculate their sum value, minus the fee needed to spend them
let mut sum = inputs.iter().map(|input| input.amount()).sum::<u64>();
let mut sum = outputs[0 .. input_bound].iter().map(|input| input.amount()).sum::<u64>();
// sum -= C::MAX_FEE; // TODO
// Grab the payments this will successfully fund
let mut these_payments = vec![];
for payment in &payments {
if sum > payment.1 {
these_payments.push(payment);
sum -= payment.1;
}
let mut p = 0;
while p < payments.len() {
if sum >= payments[p].1 {
sum -= payments[p].1;
these_payments.push(payments.remove(p));
} else {
// Doesn't break in this else case as a smaller payment may still fit
p += 1;
}
}
// Move to the next set of keys if none of these outputs remain significant
@ -228,16 +231,17 @@ impl<D: CoinDb, C: Coin> Wallet<D, C> {
break;
}
// Drop any uneeded outputs
while sum > inputs[inputs.len() - 1].amount() {
sum -= inputs[inputs.len() - 1].amount();
inputs = &inputs[.. (inputs.len() - 1)];
// Drop any uneeded inputs
while sum > outputs[input_bound - 1].amount() {
sum -= outputs[input_bound - 1].amount();
input_bound -= 1;
}
// TODO: Replace any high value inputs with low value inputs, if we can
// We now have a minimal effective outputs/payments set
// Take ownership while removing these candidates from the provided list
let inputs = outputs.drain(.. inputs.len()).collect();
let payments = payments.drain(.. these_payments.len()).collect::<Vec<_>>();
let inputs = outputs.drain(.. input_bound).collect();
let mut transcript = Transcript::new(b"Serai Processor Wallet Send");
transcript.append_message(
@ -257,7 +261,7 @@ impl<D: CoinDb, C: Coin> Wallet<D, C> {
transcript,
acknowledged_height,
inputs,
&payments
&these_payments
).await?;
// self.db.save_tx(tx) // TODO
txs.push(tx);