path: root/src/declarative/qml/qmlboundsignal.cpp

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#include "qmlboundsignal_p.h"
#include "private/qmetaobjectbuilder_p.h"
#include "private/qmlengine_p.h"
#include "private/qmlexpression_p.h"
#include "private/qmlcontext_p.h"
#include <qmlmetatype.h>
#include <qml.h>
#include <qmlcontext.h>
#include <QtCore/qdebug.h>
#include <private/qmlglobal_p.h>

QT_BEGIN_NAMESPACE

class QmlBoundSignalParameters : public QObject
{
Q_OBJECT
public:
    QmlBoundSignalParameters(const QMetaMethod &, QObject * = 0);
    ~QmlBoundSignalParameters();

    void setValues(void **);
    void clearValues();

private:
    friend class MetaObject;
    int metaCall(QMetaObject::Call, int _id, void **);
    struct MetaObject : public QAbstractDynamicMetaObject {
        MetaObject(QmlBoundSignalParameters *b)
            : parent(b) {}

        int metaCall(QMetaObject::Call c, int id, void **a) { 
            return parent->metaCall(c, id, a);
        }
        QmlBoundSignalParameters *parent;
    };

    int *types;
    void **values;
    QMetaObject *myMetaObject;
};

static int evaluateIdx = -1;

QmlAbstractBoundSignal::QmlAbstractBoundSignal(QObject *parent)
: QObject(parent)
{
}

QmlAbstractBoundSignal::~QmlAbstractBoundSignal()
{
}

QmlBoundSignal::QmlBoundSignal(QObject *scope, const QMetaMethod &signal, 
                               QObject *parent)
: m_expression(0), m_idx(signal.methodIndex()), m_params(0)
{
    // A cached evaluation of the QmlExpression::value() slot index.
    //
    // This is thread safe.  Although it may be updated by two threads, they
    // will both set it to the same value - so the worst thing that can happen
    // is that they both do the work to figure it out.  Boo hoo.
    if (evaluateIdx == -1) evaluateIdx = metaObject()->methodCount();

    QmlGraphics_setParent_noEvent(this, parent);
    QMetaObject::connect(scope, m_idx, this, evaluateIdx);

    if (!signal.parameterTypes().isEmpty())
        m_params = new QmlBoundSignalParameters(signal, this);
}

QmlBoundSignal::QmlBoundSignal(QmlContext *ctxt, const QString &val, 
                               QObject *scope, const QMetaMethod &signal,
                               QObject *parent)
: m_expression(0), m_idx(signal.methodIndex()), m_params(0)
{
    // A cached evaluation of the QmlExpression::value() slot index.
    //
    // This is thread safe.  Although it may be updated by two threads, they
    // will both set it to the same value - so the worst thing that can happen
    // is that they both do the work to figure it out.  Boo hoo.
    if (evaluateIdx == -1) evaluateIdx = metaObject()->methodCount();

    QmlGraphics_setParent_noEvent(this, parent);
    QMetaObject::connect(scope, m_idx, this, evaluateIdx);

    m_expression = new QmlExpression(ctxt, val, scope);
    m_expression->setTrackChange(false);

    if (!signal.parameterTypes().isEmpty())
        m_params = new QmlBoundSignalParameters(signal, this);
}

QmlBoundSignal::~QmlBoundSignal()
{
    delete m_expression;
    m_expression = 0;
}

int QmlBoundSignal::index() const 
{ 
    return m_idx; 
}

/*!
    Returns the signal expression.
*/
QmlExpression *QmlBoundSignal::expression() const
{
    return m_expression;
}

/*!
    Sets the signal expression to \a e.  Returns the current signal expression,
    or null if there is no signal expression.

    The QmlBoundSignal instance takes ownership of \a e.  The caller is 
    assumes ownership of the returned QmlExpression.
*/
QmlExpression *QmlBoundSignal::setExpression(QmlExpression *e)
{
    QmlExpression *rv = m_expression;
    m_expression = e;
    if (m_expression) m_expression->setTrackChange(false);
    return rv;
}

QmlBoundSignal *QmlBoundSignal::cast(QObject *o)
{
    QmlAbstractBoundSignal *s = qobject_cast<QmlAbstractBoundSignal*>(o);
    return static_cast<QmlBoundSignal *>(s);
}

int QmlBoundSignal::qt_metacall(QMetaObject::Call c, int id, void **a)
{
    if (c == QMetaObject::InvokeMetaMethod && id == evaluateIdx) {
        if (m_params) m_params->setValues(a);
        if (m_expression) {
            QmlExpressionPrivate::get(m_expression)->value(m_params);
            if (m_expression && m_expression->hasError())
                qWarning().nospace() << qPrintable(m_expression->error().toString());
        }
        if (m_params) m_params->clearValues();
        return -1;
    } else {
        return QObject::qt_metacall(c, id, a);
    }
}

QmlBoundSignalParameters::QmlBoundSignalParameters(const QMetaMethod &method, 
                                                   QObject *parent)
: QObject(parent), types(0), values(0)
{
    MetaObject *mo = new MetaObject(this);

    // ### Optimize!
    // ### Ensure only supported types are allowed, otherwise it might crash
    QMetaObjectBuilder mob;
    mob.setSuperClass(&QmlBoundSignalParameters::staticMetaObject);
    mob.setClassName("QmlBoundSignalParameters");

    QList<QByteArray> paramTypes = method.parameterTypes();
    QList<QByteArray> paramNames = method.parameterNames();
    types = new int[paramTypes.count()];
    for (int ii = 0; ii < paramTypes.count(); ++ii) {
        const QByteArray &type = paramTypes.at(ii);
        const QByteArray &name = paramNames.at(ii);

        if (name.isEmpty() || type.isEmpty()) {
            types[ii] = 0;
            continue;
        }

        QVariant::Type t = (QVariant::Type)QMetaType::type(type.constData());
        if (QmlMetaType::isObject(t)) {
            types[ii] = QMetaType::QObjectStar;
            QMetaPropertyBuilder prop = mob.addProperty(name, "QObject*");
            prop.setWritable(false);
        } else {
            types[ii] = t;
            QMetaPropertyBuilder prop = mob.addProperty(name, type);
            prop.setWritable(false);
        }
    }
    myMetaObject = mob.toMetaObject();
    *static_cast<QMetaObject *>(mo) = *myMetaObject;

    d_ptr->metaObject = mo;
}

QmlBoundSignalParameters::~QmlBoundSignalParameters()
{
    delete [] types;
    qFree(myMetaObject);
}

void QmlBoundSignalParameters::setValues(void **v)
{
    values = v;
}

void QmlBoundSignalParameters::clearValues()
{
    values = 0;
}

int QmlBoundSignalParameters::metaCall(QMetaObject::Call c, int id, void **a)
{
    if (!values)
        return -1;

    if (c == QMetaObject::ReadProperty && id >= 1) {
        QmlMetaType::copy(types[id - 1], a[0], values[id]);
        return -1;
    } else {
        return qt_metacall(c, id, a);
    }
}

QT_END_NAMESPACE

#include "qmlboundsignal.moc"