Merge bitcoin-core/gui#598: Avoid recalculating the wallet balance - use model cache

4584d300a40bfd84517072f7a6eee114fb7cab08 GUI: remove now unneeded 'm_balances' field from overviewpage (furszy)
050e8b139145d6991e740b0e5f2b3364663dd348 GUI: 'getAvailableBalance', use cached balance if the user did not select UTXO manually (furszy)
96e3264a82c51b456703f500bd98e8cb98115697 GUI: use cached balance in overviewpage and sendcoinsdialog (furszy)
321335bf0292034d79afa6c44f7f072942b6cc3c GUI: add getter for WalletModel::m_cached_balances field (furszy)
e62958dc81d215a1c56318d0914dfd9a33d45973 GUI: sendCoinsDialog, remove duplicate wallet().getBalances() call (furszy)

Pull request description:

  As per the title says, we are recalculating the entire wallet balance on different situations calling to `wallet().getBalances()`, when should instead make use of the wallet model cached balance.

  This has the benefits of (1) not spending resources calculating a balance that we already have cached, and (2) avoid blocking the main thread for a long time, in case of big wallets, walking through the entire wallet's tx map more than what it's really needed.

  Changes:

  1) Fix: `SendCoinsDialog` was calling `wallet().getBalances()` twice during `setModel`.
  2) Use the cached balance if the user did not select any UTXO manually inside the wallet model `getAvailableBalance` call.

  -----------------------
  As an extra note, this work born in [#25005](https://github.com/bitcoin/bitcoin/pull/25005) but grew out of scope of it.

ACKs for top commit:
  jarolrod:
    ACK 4584d300a40bfd84517072f7a6eee114fb7cab08
  hebasto:
    re-ACK 4584d300a40bfd84517072f7a6eee114fb7cab08, only suggested changes and commit message formatting since my [recent](https://github.com/bitcoin-core/gui/pull/598#pullrequestreview-1071268192) review.

Tree-SHA512: 6633ce7f9a82a3e46e75aa7295df46c80a4cd4a9f3305427af203c9bc8670573fa8a1927f14a279260c488cc975a08d238faba2e9751588086fea1dcf8ea2b28

1 files changed, 13 insertions, 15 deletions

diff --git a/src/qt/test/wallettests.cpp b/src/qt/test/wallettests.cpp
index b8ae62ecab..7e39829038 100644
--- a/src/qt/test/wallettests.cpp
+++ b/src/qt/test/wallettests.cpp
@@ -129,6 +129,13 @@ void BumpFee(TransactionView& view, const uint256& txid, bool expectDisabled, st
     QVERIFY(text.indexOf(QString::fromStdString(expectError)) != -1);
 }
 
+void CompareBalance(WalletModel& walletModel, CAmount expected_balance, QLabel* balance_label_to_check)
+{
+    BitcoinUnit unit = walletModel.getOptionsModel()->getDisplayUnit();
+    QString balanceComparison = BitcoinUnits::formatWithUnit(unit, expected_balance, false, BitcoinUnits::SeparatorStyle::ALWAYS);
+    QCOMPARE(balance_label_to_check->text().trimmed(), balanceComparison);
+}
+
 //! Simple qt wallet tests.
 //
 // Test widgets can be debugged interactively calling show() on them and
@@ -195,15 +202,10 @@ void TestGUI(interfaces::Node& node)
     sendCoinsDialog.setModel(&walletModel);
     transactionView.setModel(&walletModel);
 
-    {
-        // Check balance in send dialog
-        QLabel* balanceLabel = sendCoinsDialog.findChild<QLabel*>("labelBalance");
-        QString balanceText = balanceLabel->text();
-        BitcoinUnit unit = walletModel.getOptionsModel()->getDisplayUnit();
-        CAmount balance = walletModel.wallet().getBalance();
-        QString balanceComparison = BitcoinUnits::formatWithUnit(unit, balance, false, BitcoinUnits::SeparatorStyle::ALWAYS);
-        QCOMPARE(balanceText, balanceComparison);
-    }
+    // Update walletModel cached balance which will trigger an update for the 'labelBalance' QLabel.
+    walletModel.pollBalanceChanged();
+    // Check balance in send dialog
+    CompareBalance(walletModel, walletModel.wallet().getBalance(), sendCoinsDialog.findChild<QLabel*>("labelBalance"));
 
     // Send two transactions, and verify they are added to transaction list.
     TransactionTableModel* transactionTableModel = walletModel.getTransactionTableModel();
@@ -223,12 +225,8 @@ void TestGUI(interfaces::Node& node)
     // Check current balance on OverviewPage
     OverviewPage overviewPage(platformStyle.get());
     overviewPage.setWalletModel(&walletModel);
-    QLabel* balanceLabel = overviewPage.findChild<QLabel*>("labelBalance");
-    QString balanceText = balanceLabel->text().trimmed();
-    BitcoinUnit unit = walletModel.getOptionsModel()->getDisplayUnit();
-    CAmount balance = walletModel.wallet().getBalance();
-    QString balanceComparison = BitcoinUnits::formatWithUnit(unit, balance, false, BitcoinUnits::SeparatorStyle::ALWAYS);
-    QCOMPARE(balanceText, balanceComparison);
+    walletModel.pollBalanceChanged(); // Manual balance polling update
+    CompareBalance(walletModel, walletModel.wallet().getBalance(), overviewPage.findChild<QLabel*>("labelBalance"));
 
     // Check Request Payment button
     ReceiveCoinsDialog receiveCoinsDialog(platformStyle.get());