taler-typescript-core

commit 1cdd1641c317933b2c935fd8540e06befd492395
parent 2015d76af1721e81cc00fd6640ec07b94fc65cb6
Author: Florian Dold <florian@dold.me>
Date:   Sun,  4 May 2025 00:33:33 +0200

wallet-core: limit output size of refresh sessions

Diffstat:
M
packages/taler-wallet-core/src/denomSelection.ts
 | 
8
+++++++-
M
packages/taler-wallet-core/src/refresh.ts
 | 
27
+++++++++++++++++----------

2 files changed, 24 insertions(+), 11 deletions(-)
diff --git a/packages/taler-wallet-core/src/denomSelection.ts b/packages/taler-wallet-core/src/denomSelection.ts
@@ -44,6 +44,7 @@ const logger = new Logger("denomSelection.ts");
 export function selectWithdrawalDenominations(
   amountAvailable: AmountJson,
   denoms: DenominationRecord[],
+  opts: { limitCoins?: number } = {},
 ): DenomSelectionState {
   let remaining = Amounts.copy(amountAvailable);
 
@@ -66,10 +67,15 @@ export function selectWithdrawalDenominations(
     );
   }
 
+  let totalCount = 0;
+
   for (const d of denoms) {
     const cost = Amounts.add(d.value, d.fees.feeWithdraw).amount;
     const res = Amounts.divmod(remaining, cost);
-    const count = res.quotient;
+    let count = res.quotient;
+    if (opts.limitCoins != null && totalCount + count > opts.limitCoins) {
+      count = opts.limitCoins - totalCount;
+    }
     remaining = Amounts.sub(remaining, Amounts.mult(cost, count).amount).amount;
     if (count > 0) {
       totalCoinValue = Amounts.add(
diff --git a/packages/taler-wallet-core/src/refresh.ts b/packages/taler-wallet-core/src/refresh.ts
@@ -133,6 +133,9 @@ import {
 } from "./wallet.js";
 import { getWithdrawableDenomsTx } from "./withdraw.js";
 
+/** Maximum number of new coins. */
+const maxRefreshSessionSize = 64;
+
 const logger = new Logger("refresh.ts");
 
 export class RefreshTransactionContext implements TransactionContext {
@@ -417,7 +420,9 @@ export async function getTotalRefreshCost(
   amountLeft: AmountJson,
 ): Promise<AmountJson> {
   const { exchangeBaseUrl, denomPubHash } = refreshedDenom;
-  const key = `denom=${exchangeBaseUrl}/${denomPubHash};left=${Amounts.stringify(amountLeft)}`;
+  const key = `denom=${exchangeBaseUrl}/${denomPubHash};left=${Amounts.stringify(
+    amountLeft,
+  )}`;
   return wex.ws.refreshCostCache.getOrPut(key, async () => {
     const allDenoms = await getWithdrawableDenomsTx(
       wex,
@@ -425,12 +430,8 @@ export async function getTotalRefreshCost(
       exchangeBaseUrl,
       Amounts.currencyOf(amountLeft),
     );
-    return getTotalRefreshCostInternal(
-      allDenoms,
-      refreshedDenom,
-      amountLeft,
-    );
-  })
+    return getTotalRefreshCostInternal(allDenoms, refreshedDenom, amountLeft);
+  });
 }
 
 /**
@@ -450,7 +451,8 @@ export function getTotalRefreshCostInternal(
   amountLeft: AmountJson,
 ): AmountJson {
   logger.trace(
-    `computing total refresh cost, denom value ${refreshedDenom.value
+    `computing total refresh cost, denom value ${
+      refreshedDenom.value
     }, amount left ${Amounts.stringify(amountLeft)}`,
   );
   const withdrawAmount = Amounts.sub(
@@ -458,7 +460,9 @@ export function getTotalRefreshCostInternal(
     refreshedDenom.feeRefresh,
   ).amount;
   const denomMap = Object.fromEntries(denoms.map((x) => [x.denomPubHash, x]));
-  const withdrawDenoms = selectWithdrawalDenominations(withdrawAmount, denoms);
+  const withdrawDenoms = selectWithdrawalDenominations(withdrawAmount, denoms, {
+    limitCoins: maxRefreshSessionSize,
+  });
   const resultingAmount = Amounts.add(
     Amounts.zeroOfCurrency(withdrawAmount.currency),
     ...withdrawDenoms.selectedDenoms.map(
@@ -552,6 +556,9 @@ async function initRefreshSession(
   const newCoinDenoms = selectWithdrawalDenominations(
     availableAmount,
     availableDenoms,
+    {
+      limitCoins: maxRefreshSessionSize,
+    },
   );
 
   if (newCoinDenoms.selectedDenoms.length === 0) {
@@ -1615,7 +1622,7 @@ async function refreshReveal(
         );
         checkDbInvariant(
           car.pendingRefreshOutputCount != null &&
-          car.pendingRefreshOutputCount > 0,
+            car.pendingRefreshOutputCount > 0,
           `no pendingRefreshOutputCount for denom ${coin.denomPubHash} age ${coin.maxAge}`,
         );
         car.pendingRefreshOutputCount--;