Merge #2075: [GUI] Settings information, fix missing initial masternodes count value.

164d6aa GUI: settings information, fix missing initial masternodes count value. (furszy)

Pull request description:

  The count isn't updated on every widget show, only via the event (which only happen every 40 minutes as Masternodes updates aren't regular at all).
  This PR fixes it updating the masternode count every time that the screen is visible, then the event is in charge of update it if the user stays there long enough.

ACKs for top commit:
  random-zebra:
    Nice. ACK 164d6aa
  Fuzzbawls:
    ACK 164d6aa

Tree-SHA512: 6624ee2f408601e46853dc2cd57c5c679736aad8798b38b846af28c59a89a01d9fa2b9027486f6195b8265a2d50fabc9013f90940fc2dda349798b564b510dc0

Author: furszy

src/qt/clientmodel.cpp

@@ -83,6 +83,17 @@ QString ClientModel::getMasternodeCountString() const
     return tr("Total: %1 (IPv4: %2 / IPv6: %3 / Tor: %4 / Unknown: %5)").arg(QString::number(total)).arg(QString::number((int)ipv4)).arg(QString::number((int)ipv6)).arg(QString::number((int)onion)).arg(QString::number((int)nUnknown));
 }
 
+QString ClientModel::getMasternodesCount()
+{
+    if (!cachedMasternodeCountString.isEmpty()) {
+        return cachedMasternodeCountString;
+    }
+
+    // Force an update
+    cachedMasternodeCountString = getMasternodeCountString();
+    return cachedMasternodeCountString;
+}
+
 int ClientModel::getNumBlocks()
 {
     if (!cacheTip) {
@@ -139,12 +150,8 @@ void ClientModel::updateTimer()
 
 void ClientModel::updateMnTimer()
 {
-    // Get required lock upfront. This avoids the GUI from getting stuck on
-    // periodical polls if the core is holding the locks for a longer time -
-    // for example, during a wallet rescan.
-    TRY_LOCK(cs_main, lockMain);
-    if (!lockMain)
-        return;
+    // Following method is locking the mnmanager mutex for now,
+    // future: move to an event based update.
     QString newMasternodeCountString = getMasternodeCountString();
 
     if (cachedMasternodeCountString != newMasternodeCountString) {

src/qt/clientmodel.h

@@ -89,6 +89,9 @@ class ClientModel : public QObject
     // Start/Stop the masternode polling timer
     void startMasternodesTimer();
     void stopMasternodesTimer();
+    // Force a MN count update calling mnmanager directly locking its internal mutex.
+    // Future todo: implement an event based update and remove the lock requirement.
+    QString getMasternodesCount();
 
 private:
     QString getMasternodeCountString() const;

src/qt/pivx/settings/settingsinformationwidget.cpp

@@ -1,6 +1,6 @@
 // Copyright (c) 2019-2020 The PIVX developers
 // Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+// file COPYING or https://www.opensource.org/licenses/mit-license.php.
 
 #include "qt/pivx/settings/settingsinformationwidget.h"
 #include "qt/pivx/settings/forms/ui_settingsinformationwidget.h"
@@ -14,6 +14,8 @@
 
 #include <QDir>
 
+#define REQUEST_UPDATE_MN_COUNT 0
+
 SettingsInformationWidget::SettingsInformationWidget(PIVXGUI* _window,QWidget *parent) :
     PWidget(_window,parent),
     ui(new Ui::SettingsInformationWidget)
@@ -165,6 +167,8 @@ void SettingsInformationWidget::showEvent(QShowEvent *event)
     QWidget::showEvent(event);
     if (clientModel) {
         clientModel->startMasternodesTimer();
+        // Initial masternodes count value, running in a worker thread to not lock mnmanager mutex in the main thread.
+        execute(REQUEST_UPDATE_MN_COUNT);
     }
 }
 
@@ -175,6 +179,21 @@ void SettingsInformationWidget::hideEvent(QHideEvent *event) {
     }
 }
 
+void SettingsInformationWidget::run(int type)
+{
+    if (type == REQUEST_UPDATE_MN_COUNT) {
+        QMetaObject::invokeMethod(this, "setMasternodeCount",
+                                  Qt::QueuedConnection, Q_ARG(QString, clientModel->getMasternodesCount()));
+    }
+}
+
+void SettingsInformationWidget::onError(QString error, int type)
+{
+    if (type == REQUEST_UPDATE_MN_COUNT) {
+        setMasternodeCount(tr("No available data"));
+    }
+}
+
 SettingsInformationWidget::~SettingsInformationWidget()
 {
     delete ui;

src/qt/pivx/settings/settingsinformationwidget.h

@@ -19,19 +19,22 @@ class SettingsInformationWidget : public PWidget
 
 public:
     explicit SettingsInformationWidget(PIVXGUI* _window, QWidget *parent = nullptr);
-    ~SettingsInformationWidget();
+    ~SettingsInformationWidget() override;
 
     void loadClientModel() override;
 
+    void run(int type) override;
+    void onError(QString error, int type) override;
+
 private Q_SLOTS:
     void setNumConnections(int count);
     void setNumBlocks(int count);
-    void setMasternodeCount(const QString& strMasternodes);
     void showEvent(QShowEvent* event) override;
     void hideEvent(QHideEvent* event) override;
 
 public Q_SLOTS:
     void openNetworkMonitor();
+    void setMasternodeCount(const QString& strMasternodes);
 
 private:
     Ui::SettingsInformationWidget *ui;