From 3242f00812f08a72733f0a76aaaf5bd0cca68c12 Mon Sep 17 00:00:00 2001
From: Craig Raw <craigraw@gmail.com>
Date: Thu, 15 Jun 2023 12:19:09 +0200
Subject: [PATCH] improve performance on large wallets with high address reuse

---
 .../sparrowwallet/sparrow/net/ElectrumServer.java    |  7 ++++---
 .../sparrow/wallet/WalletTransactionsEntry.java      | 12 ++++++------
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/main/java/com/sparrowwallet/sparrow/net/ElectrumServer.java b/src/main/java/com/sparrowwallet/sparrow/net/ElectrumServer.java
index 20b05df7..055025b0 100644
--- a/src/main/java/com/sparrowwallet/sparrow/net/ElectrumServer.java
+++ b/src/main/java/com/sparrowwallet/sparrow/net/ElectrumServer.java
@@ -692,7 +692,9 @@ public class ElectrumServer {
         //First check all provided txes that pay to this node
         Script nodeScript = node.getOutputScript();
         Set<BlockTransactionHash> history = nodeTransactionMap.get(node);
+        Map<Sha256Hash, BlockTransactionHash> txHashHistory = new HashMap<>();
         for(BlockTransactionHash reference : history) {
+            txHashHistory.put(reference.getHash(), reference);
             BlockTransaction blockTransaction = wallet.getTransactions().get(reference.getHash());
             if(blockTransaction == null) {
                 throw new IllegalStateException("Did not retrieve transaction for hash " + reference.getHashAsString());
@@ -731,14 +733,13 @@ public class ElectrumServer {
                     throw new IllegalStateException("Could not retrieve transaction for hash " + reference.getHashAsString());
                 }
 
-                Optional<BlockTransactionHash> optionalTxHash = history.stream().filter(txHash -> txHash.getHash().equals(previousHash)).findFirst();
-                if(optionalTxHash.isEmpty()) {
+                BlockTransactionHash spentTxHash = txHashHistory.get(previousHash);
+                if(spentTxHash == null) {
                     //No previous transaction history found, cannot check if spends from wallet
                     //This is fine so long as all referenced transactions have been returned, in which case this refers to a transaction that does not affect this wallet node
                     continue;
                 }
 
-                BlockTransactionHash spentTxHash = optionalTxHash.get();
                 TransactionOutput spentOutput = previousTransaction.getTransaction().getOutputs().get((int)input.getOutpoint().getIndex());
                 if(spentOutput.getScript().equals(nodeScript)) {
                     BlockTransactionHashIndex spendingTXI = new BlockTransactionHashIndex(reference.getHash(), reference.getHeight(), blockTransaction.getDate(), reference.getFee(), inputIndex, spentOutput.getValue());
diff --git a/src/main/java/com/sparrowwallet/sparrow/wallet/WalletTransactionsEntry.java b/src/main/java/com/sparrowwallet/sparrow/wallet/WalletTransactionsEntry.java
index 2d3e0fbb..ad06421f 100644
--- a/src/main/java/com/sparrowwallet/sparrow/wallet/WalletTransactionsEntry.java
+++ b/src/main/java/com/sparrowwallet/sparrow/wallet/WalletTransactionsEntry.java
@@ -1,5 +1,6 @@
 package com.sparrowwallet.sparrow.wallet;
 
+import com.google.common.collect.Sets;
 import com.sparrowwallet.drongo.KeyPurpose;
 import com.sparrowwallet.drongo.protocol.HashIndex;
 import com.sparrowwallet.drongo.wallet.BlockTransaction;
@@ -72,15 +73,14 @@ public class WalletTransactionsEntry extends Entry {
                 .collect(Collectors.toUnmodifiableMap(entry -> new HashIndex(entry.getKey().getHash(), entry.getKey().getIndex()), Map.Entry::getKey,
                         BinaryOperator.maxBy(BlockTransactionHashIndex::compareTo)));
 
-        List<Entry> current = getWalletTransactions(getWallet()).stream().map(WalletTransaction::getTransactionEntry).collect(Collectors.toList());
-        List<Entry> previous = new ArrayList<>(getChildren());
+        Collection<WalletTransactionsEntry.WalletTransaction> entries = getWalletTransactions(getWallet());
+        Set<Entry> current = entries.stream().map(WalletTransaction::getTransactionEntry).collect(Collectors.toCollection(LinkedHashSet::new));
+        Set<Entry> previous = new LinkedHashSet<>(getChildren());
 
-        List<Entry> entriesAdded = new ArrayList<>(current);
-        entriesAdded.removeAll(previous);
+        Set<Entry> entriesAdded = Sets.difference(current, previous);
         getChildren().addAll(entriesAdded);
 
-        List<Entry> entriesRemoved = new ArrayList<>(previous);
-        entriesRemoved.removeAll(current);
+        Set<Entry> entriesRemoved = Sets.difference(previous, current);
         getChildren().removeAll(entriesRemoved);
 
         calculateBalances(true);