Used map for efficient storing of hashes

pkg/maintainer/spv/moved_funds_sweep.go

@@ -165,20 +165,20 @@ func getUnprovenMovedFundsSweepTransactions(
 	}
 
 	// Any wallet that was among target wallets recently could have created
-	// a moved funds sweep transaction.
-	targetWallets := [][20]byte{}
+	// a moved funds sweep transaction. One target wallet can appear in multiple
+	// events as multiple source wallets can use the same target wallets. Store
+	// wallet public key hashes in a map to get rid of duplicates.
+	walletPublicKeyHashes := make(map[[20]byte]bool)
+
 	for _, event := range events {
-		targetWallets = append(targetWallets, event.TargetWallets...)
+		for _, targetWallet := range event.TargetWallets {
+			walletPublicKeyHashes[targetWallet] = true
+		}
 	}
 
-	// Some target wallets may appear on the list multiple times. It can happen
-	// if multiple source wallets used the same target wallet. Make a list
-	// of unique wallets.
-	walletPublicKeyHashes := uniqueKeyHashes(targetWallets)
-
 	unprovenMovedFundsSweepTransactions := []*bitcoin.Transaction{}
 
-	for _, walletPublicKeyHash := range walletPublicKeyHashes {
+	for walletPublicKeyHash := range walletPublicKeyHashes {
 		wallet, err := spvChain.GetWallet(walletPublicKeyHash)
 		if err != nil {
 			return nil, fmt.Errorf("failed to get wallet: [%v]", err)

pkg/maintainer/spv/moved_funds_sweep_test.go

@@ -3,6 +3,7 @@ package spv
 import (
 	"encoding/hex"
 	"fmt"
+	"sort"
 	"testing"
 
 	"github.com/go-test/deep"
@@ -372,6 +373,12 @@ func TestGetUnprovenMovedFundsSweepTransactions(t *testing.T) {
 		wallets[2].transactions[0].Hash(), // Wallet 3 - Transaction 1
 	}
 
+	// The order of returned transaction hashes is random. Sort them before
+	// comapring.
+	sort.Slice(transactionsHashes, func(i, j int) bool {
+		return transactionsHashes[i].String() < transactionsHashes[j].String()
+	})
+
 	if diff := deep.Equal(expectedTransactionsHashes, transactionsHashes); diff != nil {
 		t.Errorf("invalid unproven transaction hashes: %v", diff)
 	}

pkg/maintainer/spv/spv.go

@@ -457,25 +457,6 @@ func uniqueWalletPublicKeyHashes[T walletEvent](events []T) [][20]byte {
 	return publicKeyHashes
 }
 
-// uniqueKeyHashes parses the list of 20-byte-long key hashes and returns a list
-// of unique key hashes.
-func uniqueKeyHashes(keyHashes [][20]byte) [][20]byte {
-	cache := make(map[string]struct{})
-	var unique [][20]byte
-
-	for _, keyHash := range keyHashes {
-		strKey := hex.EncodeToString(keyHash[:])
-
-		// Check for uniqueness
-		if _, exists := cache[strKey]; !exists {
-			cache[strKey] = struct{}{}
-			unique = append(unique, keyHash)
-		}
-	}
-
-	return unique
-}
-
 // spvProofAssembler is a type representing a function that is used
 // to assemble an SPV proof for the given transaction hash and confirmations
 // count.