qml memory leak

john shepard

//TestMix.h
#ifndef TESTMIX_H
#define TESTMIX_H

#include <QObject>
#include <QSharedPointer>
#include <QVariantMap>
#include <QJSValue>
#include <QJsonValue>
#include <QVector>
//#include "customdata.h"
class TestMix : public QObject {
Q_OBJECT
public:
explicit TestMix(QObject* parent=nullptr);
TestMix(const TestMix& src);
// Q_INVOKABLE void emitCustomData();
// Q_INVOKABLE void emitCustomData2();
Q_INVOKABLE void emitCustomData3();
Q_INVOKABLE void emitCustomData4();
Q_INVOKABLE void emitCustomData5();
Q_INVOKABLE void emitCustomData6();
Q_INVOKABLE void emitCustomData7();
Q_INVOKABLE void emitCustomData8();
Q_INVOKABLE void emitCustomData9();
signals:
//void testCustomData(CustomData* data);
//void testCustomData2(QSharedPointer<CustomData> data);
void testCustomData3(QVariantMap data);
void testCustomData4(QByteArray data);

void testCustomData5(QString data);
void testCustomData6(QStringList data);
void testCustomData7(QJSValue value);
void testCustomData8(QString value);

void testCustomData9(QList<int> data);

};

#endif // TESTMIX_H

//testmix.cpp
#include <QVariant>
#include <QQmlEngine>
#include <QJSEngine>
#include <QVector>
#include <QJsonObject>
#include <QJsonArray>
#include <QJsonDocument>
#include <QDebug>
#include "testmix.h"

TestMix::TestMix(QObject* parent)
: QObject(parent) {

}

//void TestMix::emitCustomData() {
// CustomData* data = new CustomData(this);
// data->setStrValue("Hello");
// data->setIValue(12);
// data->setFValue(1.2f);
// data->setDValue(12.99);
// QQmlEngine::setObjectOwnership(data, QQmlEngine::JavaScriptOwnership);
// emit testCustomData(data);
//}

//void TestMix::emitCustomData2() {
// QSharedPointer<CustomData> data(new CustomData(this));
// data->setStrValue("Hello");
// data->setIValue(12);
// data->setFValue(1.2f);
// data->setDValue(12.99);
// emit testCustomData2(data);

//}

void TestMix::emitCustomData3() {
QVariantMap d;
d["strValue"] = "hello";
d["iValue"] = 12;
d["fValue"] = 12.04f;
d["dValue"] = 12.333;
d["trest"] = QByteArray(10000000,0);

emit testCustomData3(d);

}

void TestMix::emitCustomData4() {
QByteArray data(1000000, 0);
emit testCustomData4(data);
}

void TestMix::emitCustomData5() {
QString d;
d.resize(1000000);
emit testCustomData5(d);
}

void TestMix::emitCustomData6() {
QStringList d;
for (int i = 0; i < 100000; ++i) {
d.append("xxxxx");
}

emit testCustomData6(d);
d.clear();

}

void TestMix::emitCustomData7() {
QJSEngine engine;
QJSValue d = engine.newObject();
d.setProperty("name", engine.newArray(1000000));
d.setProperty("xx", 2);
emit testCustomData7(d);
}

void TestMix::emitCustomData8() {
qDebug() << "test 8";
QJsonArray arr;
for (int i = 0 ; i < 20000; ++i) {
arr.append(i);
}

QJsonObject o;
o["name"] = "test8";
o["value"] = arr;

QJsonDocument doc(o);
QString json = doc.toJson();
emit testCustomData8(json);

}

void TestMix::emitCustomData9() {
QList<int> d;
for (int i = 0; i < 100000; ++ i) {
d.append(i);
}
emit testCustomData9(d);
}

//main.cpp
#include <QGuiApplication>
#include <QQmlApplicationEngine>
#include "customdata.h"
#include "testmix.h"
int main(int argc, char *argv[])
{
QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);

QGuiApplication app(argc, argv);
qmlRegisterType<TestMix>("TestMix", 1, 0, "TestMix");
QQmlApplicationEngine engine;
const QUrl url(QStringLiteral("qrc:/main.qml"));
QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
                 &app, [url](QObject *obj, const QUrl &objUrl) {
    if (!obj && url == objUrl)
        QCoreApplication::exit(-1);
}, Qt::QueuedConnection);
engine.load(url);

return app.exec();

}

//main.qml
import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls 2.12
import TestMix 1.0

Window {
id: root
visible: true
width: 640
height: 480
title: qsTr("Hello World")

TestMix {
    id: testMix

// onTestCustomData: {
// for (var d in data) {
// console.log(d, data[d])
// }

// console.log("@@@@@@@@@@########################")
// console.log("strValue:", data.strValue
// , " iValue:", data.iValue
// , " fValue", data.fValue
// , " dValue", data.dValue)

// data.strValue = "1233"
// console.log("strValue:", data.strValue)
// data

// }

// onTestCustomData2: {

// for (var d in data) {
// console.log(d, data[d])
// }

// console.log("@@@@@@@@@@########################")
// console.log("strValue:", data.strValue
// , " iValue:", data.iValue
// , " fValue", data.fValue
// , " dValue", data.dValue)
// }

    onTestCustomData3:  {
        for (var d in data) {
            console.log(d, data[d])
        }

        console.log("@@@@@@@@@@########################")
        console.log("strValue:", data.strValue
                    , " iValue:", data.iValue
                    , " fValue", data.fValue
                    , " dValue", data.dValue)
        //data.destroy()
    }

    onTestCustomData4: {

    }

    onTestCustomData5: {

    }

    onTestCustomData6: {
        //console.log("test 6")
        data = undefined
    }

    onTestCustomData7: {
        for (var d in value) {
            console.log(d, value[d])
        }

       console.log(typeof value)
       console.log(value["xx"])
       console.log(value.xx)
    }

    onTestCustomData8: {
        var d = JSON.parse(value)
       console.log(d["name"])
    }

    onTestCustomData9: {
        console.log(typeof data)
        data = undefined
    }

    signal emitJavaData(var d)

    onEmitJavaData: {
        d = undefined
    }
}

Flow {
    spacing: 10
    anchors.fill: parent

// Button {
// text: qsTr("测试")
// onClicked: testMix.emitCustomData()
// }

// Button {
// text: qsTr("测试2")
// onClicked: testMix.emitCustomData2()
// }

    Button {
        text: qsTr("测试3")
        onClicked: testMix.emitCustomData3()
    }

    Button {
        text: qsTr("测试4")
        onClicked: testMix.emitCustomData4()
    }

    Button {
        text: qsTr("测试5")
        onClicked: testMix.emitCustomData5()
    }

    Button {
        text: qsTr("测试6")
        onClicked: testMix.emitCustomData6()
    }

    Button {
        text: qsTr("测试7")
        onClicked: testMix.emitCustomData7()
    }

    Button {
        text: qsTr("测试8")
        onClicked: testMix.emitCustomData8()
    }

    Button {
        text: qsTr("测试9")
        onClicked: testMix.emitCustomData9()
    }

    Button {
        text: qsTr("测试10")
        onClicked: {
            var d = new Array(1000000);
            for (var i = 0; i < d.length;  ++i){
                d[i] = Number(i);
            }

            testMix.emitJavaData(d)
            d = undefined
        }
    }
}

}

question :
clicked the button “测试6”
i found the memory leak when i track the windows task manager memory

how can I solve this problem?