Instantiate NodeModel in qml

src/Makefile.qt.include

@@ -35,6 +35,7 @@ QT_FORMS_UI = \
   qt/forms/transactiondescdialog.ui
 
 QT_MOC_CPP = \
+  qml/moc_engine.cpp \
   qml/moc_nodemodel.cpp \
   qt/moc_addressbookpage.cpp \
   qt/moc_addresstablemodel.cpp \
@@ -108,6 +109,7 @@ QT_QRC_LOCALE = qt/bitcoin_locale.qrc
 
 BITCOIN_QT_H = \
   qml/bitcoin.h \
+  qml/engine.h \
   qml/imageprovider.h \
   qml/nodemodel.h \
   qml/util.h \
@@ -286,6 +288,7 @@ BITCOIN_QT_WALLET_CPP = \
 
 BITCOIN_QML_BASE_CPP = \
   qml/bitcoin.cpp \
+  qml/engine.cpp \
   qml/imageprovider.cpp \
   qml/nodemodel.cpp \
   qml/util.cpp
@@ -444,7 +447,7 @@ ui_%.h: %.ui
 	$(AM_V_GEN) QT_SELECT=$(QT_SELECT) $(MOC) $(DEFAULT_INCLUDES) $(QT_INCLUDES_UNSUPPRESSED) $(MOC_DEFS) $< > $@
 
 moc_%.cpp: %.h
-	$(AM_V_GEN) QT_SELECT=$(QT_SELECT) $(MOC) $(DEFAULT_INCLUDES) $(QT_INCLUDES_UNSUPPRESSED) $(MOC_DEFS) $< > $@
+	$(AM_V_GEN) QT_SELECT=$(QT_SELECT) $(MOC) $(DEFAULT_INCLUDES) $(QT_INCLUDES_UNSUPPRESSED) $(QT_QUICK_CFLAGS) $(MOC_DEFS) $< > $@
 
 %.qm: %.ts
 	@test -f $(LRELEASE)

src/qml/bitcoin.cpp

@@ -11,6 +11,7 @@
 #include <logging.h>
 #include <node/ui_interface.h>
 #include <noui.h>
+#include <qml/engine.h>
 #include <qml/imageprovider.h>
 #include <qml/nodemodel.h>
 #include <qml/util.h>
@@ -29,7 +30,6 @@
 
 #include <QDebug>
 #include <QGuiApplication>
-#include <QQmlApplicationEngine>
 #include <QQmlContext>
 #include <QQuickWindow>
 #include <QString>
@@ -157,30 +157,26 @@ int QmlGuiMain(int argc, char* argv[])
 
     handler_message_box.disconnect();
 
-    NodeModel node_model{*node};
     InitExecutor init_executor{*node};
-    QObject::connect(&node_model, &NodeModel::requestedInitialize, &init_executor, &InitExecutor::initialize);
-    QObject::connect(&node_model, &NodeModel::requestedShutdown, &init_executor, &InitExecutor::shutdown);
-    QObject::connect(&init_executor, &InitExecutor::initializeResult, &node_model, &NodeModel::initializeResult);
-    QObject::connect(&init_executor, &InitExecutor::shutdownResult, qGuiApp, &QGuiApplication::quit, Qt::QueuedConnection);
-    // QObject::connect(&init_executor, &InitExecutor::runawayException, &node_model, &NodeModel::handleRunawayException);
 
     qGuiApp->setQuitOnLastWindowClosed(false);
     QObject::connect(qGuiApp, &QGuiApplication::lastWindowClosed, [&] {
         node->startShutdown();
-        node_model.startNodeShutdown();
+        init_executor.shutdown();
     });
 
     GUIUtil::LoadFont(":/fonts/inter/regular");
     GUIUtil::LoadFont(":/fonts/inter/semibold");
 
-    QQmlApplicationEngine engine;
+    qmlRegisterType<NodeModel>("BitcoinCore", 1, 0, "NodeModel");
+
+    Engine engine(*node);
 
     QScopedPointer<const NetworkStyle> network_style{NetworkStyle::instantiate(Params().NetworkIDString())};
     assert(!network_style.isNull());
     engine.addImageProvider(QStringLiteral("images"), new ImageProvider{network_style.data()});
 
-    engine.rootContext()->setContextProperty("nodeModel", &node_model);
+    engine.rootContext()->setContextProperty("initExecutor", &init_executor);
 
     engine.load(QUrl(QStringLiteral("qrc:///qml/pages/stub.qml")));
     if (engine.rootObjects().isEmpty()) {

src/qml/engine.cpp

@@ -0,0 +1,26 @@
+// Copyright (c) 2021 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <qml/engine.h>
+
+#include <interfaces/node.h>
+#include <node/context.h>
+
+#include <QQmlContext>
+
+Engine::Engine(interfaces::Node& node)
+    : m_node(node)
+{
+}
+
+Engine::~Engine()
+{
+}
+
+interfaces::Node& Engine::node(QObject* object)
+{
+    auto context = Assert(QQmlEngine::contextForObject(object));
+    auto engine = Assert(context->engine());
+    return Assert(qobject_cast<Engine*>(engine))->node();
+}

src/qml/engine.h

@@ -0,0 +1,30 @@
+// Copyright (c) 2021 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_QML_ENGINE_H
+#define BITCOIN_QML_ENGINE_H
+
+#include <QQmlApplicationEngine>
+
+namespace interfaces {
+class Node;
+}
+
+class Engine : public QQmlApplicationEngine
+{
+    Q_OBJECT
+
+public:
+    explicit Engine(interfaces::Node& node);
+    ~Engine();
+
+    interfaces::Node& node() const { return m_node; }
+
+    static interfaces::Node& node(QObject* object);
+
+private:
+    interfaces::Node& m_node;
+};
+
+#endif // BITCOIN_QML_ENGINE_H

src/qml/nodemodel.cpp

@@ -5,14 +5,15 @@
 #include <qml/nodemodel.h>
 
 #include <interfaces/node.h>
+#include <qml/engine.h>
+#include <qt/guiutil.h>
 #include <validation.h>
 
 #include <cassert>
 
-NodeModel::NodeModel(interfaces::Node& node)
-    : m_node{node}
+NodeModel::NodeModel(QObject* parent)
+    : QObject(parent)
 {
-    ConnectToBlockTipSignal();
 }
 
 void NodeModel::setBlockTipHeight(int new_height)
@@ -23,27 +24,19 @@ void NodeModel::setBlockTipHeight(int new_height)
     }
 }
 
-void NodeModel::startNodeInitializionThread()
+void NodeModel::classBegin()
 {
-    Q_EMIT requestedInitialize();
 }
 
-void NodeModel::startNodeShutdown()
-{
-    Q_EMIT requestedShutdown();
-}
-
-void NodeModel::initializeResult([[maybe_unused]] bool success, interfaces::BlockAndHeaderTipInfo tip_info)
-{
-    // TODO: Handle the `success` parameter,
-    setBlockTipHeight(tip_info.block_height);
-}
-
-void NodeModel::ConnectToBlockTipSignal()
+void NodeModel::componentComplete()
 {
+    auto& node = Engine::node(this);
+    setBlockTipHeight(node.getNumBlocks());
     assert(!m_handler_notify_block_tip);
-    m_handler_notify_block_tip = m_node.handleNotifyBlockTip(
+    m_handler_notify_block_tip = node.handleNotifyBlockTip(
         [this](SynchronizationState state, interfaces::BlockTip tip, double verification_progress) {
-            setBlockTipHeight(tip.block_height);
+            GUIUtil::ObjectInvoke(this, [=] {
+                setBlockTipHeight(tip.block_height);
+            });
         });
 }

src/qml/nodemodel.h

@@ -6,47 +6,41 @@
 #define BITCOIN_QML_NODEMODEL_H
 
 #include <interfaces/handler.h>
-#include <interfaces/node.h>
 
 #include <memory>
 
 #include <QObject>
+#include <QQmlParserStatus>
 
 namespace interfaces {
 class Node;
 }
 
 /** Model for Bitcoin network client. */
-class NodeModel : public QObject
+class NodeModel : public QObject, public QQmlParserStatus
 {
     Q_OBJECT
+    Q_INTERFACES(QQmlParserStatus)
     Q_PROPERTY(int blockTipHeight READ blockTipHeight NOTIFY blockTipHeightChanged)
 
 public:
-    explicit NodeModel(interfaces::Node& node);
+    explicit NodeModel(QObject* parent = nullptr);
 
     int blockTipHeight() const { return m_block_tip_height; }
     void setBlockTipHeight(int new_height);
 
-    Q_INVOKABLE void startNodeInitializionThread();
-    void startNodeShutdown();
-
-public Q_SLOTS:
-    void initializeResult(bool success, interfaces::BlockAndHeaderTipInfo tip_info);
+    // QQmlParserStatus
+    void classBegin() override;
+    void componentComplete() override;
 
 Q_SIGNALS:
     void blockTipHeightChanged();
-    void requestedInitialize();
-    void requestedShutdown();
 
 private:
     // Properties that are exposed to QML.
     int m_block_tip_height{0};
 
-    interfaces::Node& m_node;
     std::unique_ptr<interfaces::Handler> m_handler_notify_block_tip;
-
-    void ConnectToBlockTipSignal();
 };
 
 #endif // BITCOIN_QML_NODEMODEL_H

src/qml/pages/stub.qml

@@ -2,6 +2,7 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+import BitcoinCore 1.0
 import QtQuick 2.12
 import QtQuick.Controls 2.12
 import QtQuick.Layouts 1.11
@@ -16,33 +17,51 @@ ApplicationWindow {
     color: "black"
     visible: true
 
-    Component.onCompleted: nodeModel.startNodeInitializionThread();
+    Component.onCompleted: initExecutor.initialize()
 
-    ColumnLayout {
+    Connections {
+        target: initExecutor
+        onInitializeResult: nodeModel.initializeResult(success, tip_info)
+    }
+
+    BusyIndicator {
+        running: !initExecutor.ready
+        visible: running
         anchors.centerIn: parent
-        spacing: 15
-        width: 400
-        Image {
-            Layout.alignment: Qt.AlignCenter
-            source: "image://images/app"
-            sourceSize.width: 64
-            sourceSize.height: 64
-        }
-        BlockCounter {
-            Layout.alignment: Qt.AlignCenter
-            blockHeight: nodeModel.blockTipHeight
-        }
-        ProgressIndicator {
-            id: indicator
-            Layout.fillWidth: true
-            progress: 0.666
-            background: MouseArea {
-                onClicked: indicator.progress = mouseX / width
+    }
+
+    Loader {
+        id: loader
+        active: initExecutor.ready
+        anchors.centerIn: parent
+        sourceComponent: ColumnLayout {
+            spacing: 15
+            width: 400
+            NodeModel {
+                id: nodeModel
+            }
+            Image {
+                Layout.alignment: Qt.AlignCenter
+                source: "image://images/app"
+                sourceSize.width: 64
+                sourceSize.height: 64
+            }
+            BlockCounter {
+                Layout.alignment: Qt.AlignCenter
+                blockHeight: nodeModel.blockTipHeight
+            }
+            ProgressIndicator {
+                id: indicator
+                Layout.fillWidth: true
+                progress: 0.666
+                background: MouseArea {
+                    onClicked: indicator.progress = mouseX / width
+                }
+            }
+            ConnectionOptions {
+                Layout.preferredWidth: 400
+                focus: true
             }
-        }
-        ConnectionOptions {
-            Layout.preferredWidth: 400
-            focus: true
         }
     }
 }

src/qt/initexecutor.cpp

@@ -21,6 +21,11 @@ InitExecutor::InitExecutor(interfaces::Node& node)
 {
     m_context.moveToThread(&m_thread);
     m_thread.start();
+
+    connect(this, &InitExecutor::initializeResult, this, [=](bool success, interfaces::BlockAndHeaderTipInfo tip_info) {
+        m_ready = success;
+        Q_EMIT readyChanged();
+    });
 }
 
 InitExecutor::~InitExecutor()

src/qt/initexecutor.h

@@ -22,15 +22,19 @@ QT_END_NAMESPACE
 class InitExecutor : public QObject
 {
     Q_OBJECT
+    Q_PROPERTY(bool ready READ ready NOTIFY readyChanged)
 public:
     explicit InitExecutor(interfaces::Node& node);
     ~InitExecutor();
 
+    bool ready() const { return m_ready; }
+
 public Q_SLOTS:
     void initialize();
     void shutdown();
 
 Q_SIGNALS:
+    void readyChanged();
     void initializeResult(bool success, interfaces::BlockAndHeaderTipInfo tip_info);
     void shutdownResult();
     void runawayException(const QString& message);
@@ -42,6 +46,7 @@ public Q_SLOTS:
     interfaces::Node& m_node;
     QObject m_context;
     QThread m_thread;
+    bool m_ready{false};
 };
 
 #endif // BITCOIN_QT_INITEXECUTOR_H