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/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** This file is part of the QtScript module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL-ONLY$
** GNU Lesser General Public License Usage
** This file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** If you have questions regarding the use of this file, please contact
** us via http://www.qt-project.org/.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qscriptable.h"
#include "qscriptable_p.h"
#include "qscriptengine.h"
QT_BEGIN_NAMESPACE
/*!
\since 4.3
\class QScriptable
\brief The QScriptable class provides access to the Qt Script environment from Qt C++ member functions.
\ingroup script
With QScriptEngine::newQObject(), you can expose the signals and
slots and properties of any QObject (or subclass) to script
code. QScriptable augments this functionality by giving your C++
members access to the Qt Script environment they are invoked in;
conceptually, it is similar to QObject::sender().
By subclassing QScriptable, you get the following functions in your
class: thisObject(), argumentCount(), argument(), context() and
engine(). With these functions, you have full access to the Qt
Script environment from the slots and property access functions of
your class, when they are invoked from script code.
For example, you can throw a Qt Script exception from a slot;
manipulate the `this' object associated with the function call;
inspect the arguments stored in the QScriptContext to know the
"real" arguments passed to the function from script code; and call
script functions from your slot.
A typical use case of QScriptable is to implement prototype objects
for custom C++ types. You define the scriptable interface of your
custom type in a QScriptable subclass using properties and slots;
then you wrap an instance of your class using
QScriptEngine::newQObject(), and finally pass the result to
QScriptEngine::setDefaultPrototype(). See the \l{Default Prototypes Example}
to see how this can be done.
The following is what subclassing QScriptable typically looks
like:
\snippet doc/src/snippets/code/src_script_qscriptable.cpp 0
The only difference from regular QObject subclassing is that you
also inherit from QScriptable.
In the implementation of your slots, you can then use the functions
inherited from QScriptable:
\snippet doc/src/snippets/code/src_script_qscriptable.cpp 1
\sa {Default Prototypes Example}, QScriptEngine::newFunction()
*/
/*!
\internal
*/
QScriptable::QScriptable()
: d_ptr(new QScriptablePrivate())
{
d_ptr->q_ptr = this;
}
/*!
\internal
*/
QScriptable::~QScriptable()
{
}
/*!
Returns a pointer to the QScriptEngine associated with the current
Qt function call, or 0 if the Qt function was not invoked from
script code.
*/
QScriptEngine *QScriptable::engine() const
{
Q_D(const QScriptable);
return d->engine;
}
/*!
Returns a pointer to the QScriptContext associated with the current
Qt function call, or 0 if the Qt function was not invoked from
script code.
*/
QScriptContext *QScriptable::context() const
{
if (QScriptEngine *e = engine())
return e->currentContext();
return 0;
}
/*!
Returns the `this' object associated with the current Qt function
call, or an invalid QScriptValue if the Qt function was not invoked
from script code.
*/
QScriptValue QScriptable::thisObject() const
{
if (QScriptContext *c = context())
return c->thisObject();
return QScriptValue();
}
/*!
Returns the number of arguments passed to the function in this
invocation, or -1 if the Qt function was not invoked from script
code.
\sa argument()
*/
int QScriptable::argumentCount() const
{
if (QScriptContext *c = context())
return c->argumentCount();
return -1;
}
/*!
Returns the function argument at the given \a index, or an invalid
QScriptValue if the Qt function was not invoked from script code.
\sa argumentCount()
*/
QScriptValue QScriptable::argument(int index) const
{
if (QScriptContext *c = context())
return c->argument(index);
return QScriptValue();
}
QT_END_NAMESPACE
|
