Using QProcess in QtScript

[chiiph]

I had to change a bit the functions since QProcess can't be copied.

But now I'm having this issue:

/usr/include/qt4/QtCore/qmetatype.h: In static member function ‘static int QMetaTypeId2<T>::qt_metatype_id() [with T = QProcess]’:
/usr/include/qt4/QtCore/qmetatype.h:230:   instantiated from ‘int qMetaTypeId(T*) [with T = QProcess]’
/usr/include/qt4/QtCore/qmetatype.h:243:   instantiated from ‘int qRegisterMetaType(T*) [with T = QProcess]’
/usr/include/qt4/QtScript/qscriptengine.h:402:   instantiated from ‘int qScriptRegisterMetaType(QScriptEngine*, QScriptValue (*)(QScriptEngine*, const T&), void (*)(const QScriptValue&, T&), const QScriptValue&, T*) [with T = QProcess]’
mainwindow.cpp:69:   instantiated from here
/usr/include/qt4/QtCore/qmetatype.h:169: error: ‘qt_metatype_id’ is not a member of ‘QMetaTypeId<QProcess>’

/usr/include/qt4/QtCore/qmetatype.h: In static member function ‘static int QMetaTypeId2<T>::qt_metatype_id() [with T = QProcess]’:
/usr/include/qt4/QtCore/qmetatype.h:230:   instantiated from ‘int qMetaTypeId(T*) [with T = QProcess]’
/usr/include/qt4/QtCore/qmetatype.h:243:   instantiated from ‘int qRegisterMetaType(T*) [with T = QProcess]’
/usr/include/qt4/QtScript/qscriptengine.h:402:   instantiated from ‘int qScriptRegisterMetaType(QScriptEngine*, QScriptValue (*)(QScriptEngine*, const T&), void (*)(const QScriptValue&, T&), const QScriptValue&, T*) [with T = QProcess]’
mainwindow.cpp:69:   instantiated from here
/usr/include/qt4/QtCore/qmetatype.h:169: error: ‘qt_metatype_id’ is not a member of ‘QMetaTypeId<QProcess>’

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Any ideas?

Thanks again

[tbscope]

Yes, do not forget Q_DECLARE_METATYPE

[chiiph]

Right... I thought that was implicit since it's already a QObject...

But now:

/usr/include/qt4/QtCore/qprocess.h: In function ‘void* qMetaTypeConstructHelper(const T*) [with T = QProcess]’:
/usr/include/qt4/QtCore/qmetatype.h:196:   instantiated from ‘int qRegisterMetaType(const char*, T*) [with T = QProcess]’
mainwindow.cpp:4:   instantiated from here
/usr/include/qt4/QtCore/qprocess.h:224: error: ‘QProcess::QProcess(const QProcess&)’ is private
/usr/include/qt4/QtCore/qmetatype.h:142: error: within this context

/usr/include/qt4/QtCore/qprocess.h: In function ‘void* qMetaTypeConstructHelper(const T*) [with T = QProcess]’:
/usr/include/qt4/QtCore/qmetatype.h:196:   instantiated from ‘int qRegisterMetaType(const char*, T*) [with T = QProcess]’
mainwindow.cpp:4:   instantiated from here
/usr/include/qt4/QtCore/qprocess.h:224: error: ‘QProcess::QProcess(const QProcess&)’ is private
/usr/include/qt4/QtCore/qmetatype.h:142: error: within this context

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this isn't as easy as it sounded... at least to me...

[tbscope]

:-)

This isn't easy :-)

Wrap your QProcess in a QSharedPointer.
This whole QScript mess is very complex. On one hand you have to have copy constructors, but on the other hand, they are not allowed.
You can solve this by using a QSharedPointer

[chiiph]

I'm going to come out as the stupidest guy in here but... how can I wrap it with an object that isn't a QObject?

[tbscope]

Note: I didn't compile this, so there might be a syntax error.

Example:

QScriptValue qScriptValueFromProcess(QScriptEngine *engine, const QSharedPointer<QProcess> &object)
{
    return engine->newQObject(object.data());
}
 
void qScriptValueToProcess(const QScriptValue & value, QSharedPointer<QProcess> & object)
{
}
 
Q_SCRIPT_DECLARE_QMETAOBJECT(QProcess, QObject*)
Q_DECLARE_METATYPE(QSharedPointer<QProcess>)
 
QScriptValue processValue = m_engine->scriptValueFromQMetaObject<QProcess>();
m_engine->globalObject().setProperty("Process", processValue);
 
qScriptRegisterMetaType(m_engine, qScriptValueFromProcess, qScriptValueToProcess);

QScriptValue qScriptValueFromProcess(QScriptEngine *engine, const QSharedPointer<QProcess> &object)
{
    return engine->newQObject(object.data());
}

void qScriptValueToProcess(const QScriptValue & value, QSharedPointer<QProcess> & object)
{
}

Q_SCRIPT_DECLARE_QMETAOBJECT(QProcess, QObject*)
Q_DECLARE_METATYPE(QSharedPointer<QProcess>)

QScriptValue processValue = m_engine->scriptValueFromQMetaObject<QProcess>();
m_engine->globalObject().setProperty("Process", processValue);

qScriptRegisterMetaType(m_engine, qScriptValueFromProcess, qScriptValueToProcess);

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m_engine is a member variable containing a pointer to a script engine.

[chiiph]

Great, so now it built, but it's the same problem as before, I can declare a variable, assign new Process(), but when I call variable.start("ls") it's the same error...

Any ideas?

[tbscope]

Ohh now I remember.

The functions you want to use need to be defined as a property or a slot :-(
Try the kill() or terminate() functions, they will work.
You can write a wrapper, which is just a QProcess subclass defining the functions as slots.

Sigh... now I remember why it took me a week to get the Qt Creator cpp parser to work in scripts.

[chiiph]

GREAT!!! You're right...

At least I have some kind of idea on how to do this... because I'll need to wrap a lot more objects probably

Thanks a lot tbscope...

[tbscope]

I just tried it, and this works:

Note, I created a widget with a plain text edit and a button.

Header

class MyProcess : public QProcess
{
    Q_OBJECT
 
public:
    MyProcess(QObject* parent = 0) : QProcess(parent) {}
    ~MyProcess() {}
 
public slots:
    void startMyProcess(const QString& proc);
};
 
class Widget : public QWidget
{
    Q_OBJECT
 
public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
 
public slots:
    void runScript();
 
private:
    Ui::Widget *ui;
 
    QScriptEngine *m_engine;
};

class MyProcess : public QProcess
{
    Q_OBJECT

public:
    MyProcess(QObject* parent = 0) : QProcess(parent) {}
    ~MyProcess() {}

public slots:
    void startMyProcess(const QString& proc);
};

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();

public slots:
    void runScript();

private:
    Ui::Widget *ui;

    QScriptEngine *m_engine;
};

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Implementation:

QScriptValue qScriptValueFromProcess(QScriptEngine *engine, const QSharedPointer<MyProcess> &object)
{
    return engine->newQObject(object.data());
}
 
void qScriptValueToProcess(const QScriptValue &, QSharedPointer<MyProcess> &)
{
}
 
Q_SCRIPT_DECLARE_QMETAOBJECT(MyProcess, QObject*)
Q_DECLARE_METATYPE(QSharedPointer<MyProcess>)
 
void MyProcess::startMyProcess(const QString &proc)
{
    start(proc);
}
 
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget),
    m_engine(new QScriptEngine)
{
    ui->setupUi(this);
 
    QScriptValue processValue = m_engine->scriptValueFromQMetaObject<MyProcess>();
    m_engine->globalObject().setProperty("Process", processValue);
 
    qScriptRegisterMetaType(m_engine, qScriptValueFromProcess, qScriptValueToProcess);
 
    connect(ui->buttonRun, SIGNAL(clicked()), this, SLOT(runScript()));
}
 
Widget::~Widget()
{
    delete ui;
}
 
void Widget::runScript()
{
    QScriptValue resultValue = m_engine->evaluate(ui->textScript->toPlainText(), "test");
 
    if(resultValue.isError())
        qDebug() << "Error: " << resultValue.toString();
 
}

QScriptValue qScriptValueFromProcess(QScriptEngine *engine, const QSharedPointer<MyProcess> &object)
{
    return engine->newQObject(object.data());
}

void qScriptValueToProcess(const QScriptValue &, QSharedPointer<MyProcess> &)
{
}

Q_SCRIPT_DECLARE_QMETAOBJECT(MyProcess, QObject*)
Q_DECLARE_METATYPE(QSharedPointer<MyProcess>)

void MyProcess::startMyProcess(const QString &proc)
{
    start(proc);
}

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget),
    m_engine(new QScriptEngine)
{
    ui->setupUi(this);

    QScriptValue processValue = m_engine->scriptValueFromQMetaObject<MyProcess>();
    m_engine->globalObject().setProperty("Process", processValue);

    qScriptRegisterMetaType(m_engine, qScriptValueFromProcess, qScriptValueToProcess);

    connect(ui->buttonRun, SIGNAL(clicked()), this, SLOT(runScript()));
}

Widget::~Widget()
{
    delete ui;
}

void Widget::runScript()
{
    QScriptValue resultValue = m_engine->evaluate(ui->textScript->toPlainText(), "test");

    if(resultValue.isError())
        qDebug() << "Error: " << resultValue.toString();

}

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[chiiph]

When I try something just like you did I get "QProcess: Destroyed while process is still running"... but with static functions it works... I'm running this on Linux, may be that's the problem, I don't know... I've created a test slot that just prints a string, and it works, so this isn't a problem of calling a non-static member function...

For now I can do with the static ones, we'll see how it goes with other classes...

Thanks again for everything!

[tbscope]

You might want to keep a private pointer to an existing QProcess in the wrapper.
I did something similar here:
http://gitorious.org/qt-creator-stat...68de862ba7527b

And done a bit different:
http://doc.qt.nokia.com/4.7/script-customclass.html