src/kjsembed/value_binding.h

/* This file is part of the KDE libraries
    Copyright (C) 2005, 2006 Ian Reinhart Geiser <geiseri@kde.org>
    Copyright (C) 2005, 2006 Matt Broadstone <mbroadst@gmail.com>
    Copyright (C) 2005, 2006 Richard J. Moore <rich@kde.org>
    Copyright (C) 2005, 2006 Erik L. Bunce <kde@bunce.us>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.
*/

#ifndef VALUE_BINDING_H
#define VALUE_BINDING_H

#include <kjs/object.h>
#include <kjs/interpreter.h>

#include "static_binding.h"
#include "pointer.h"

/**
* A simple variant style method.
* This will extract the value, cast it to the native type and place it in "value".
* Any data that should be returned from this method should be placed into "result";
*
*/
#define START_VALUE_METHOD( METHODNAME, TYPE) \
    KJS::JSValue *METHODNAME( KJS::ExecState *exec, KJS::JSObject *self, const KJS::List &args ) \
    { \
        Q_UNUSED(exec);\
        Q_UNUSED(self);\
        Q_UNUSED(args);\
        KJS::JSValue *result = KJS::jsNull(); \
        KJSEmbed::ValueBinding *imp = KJSEmbed::extractBindingImp<KJSEmbed::ValueBinding>(exec, self ); \
        if( imp ) \
        { \
            TYPE value = imp->value<TYPE>();
/**
* End a variant method started by START_VALUE_METHOD
*/
#define END_VALUE_METHOD \
    imp->setValue(value); \
    } \
    else { \
        KJS::throwError(exec, KJS::GeneralError, "Problem in ValueBinding here");\
    }\
    return result; \
    }

#define KJSO_VALUE_SIMPLE_BINDING_CTOR( NAME, JSNAME, TYPE, BASENAME )        \
    NAME::NAME(KJS::ExecState *exec, const char* typeName ) \
        : BASENAME( exec, typeName )                    \
    { \
        StaticBinding::publish( exec, this, NAME::methods() ); \
    } \
    NAME::NAME(KJS::ExecState *exec, const TYPE & value) \
        : BASENAME( exec, #JSNAME , value )                    \
    { \
        StaticBinding::publish( exec, this, NAME::methods() ); \
    }

#define KJSO_VALUE_DERIVED_BINDING_CTOR( NAME, JSNAME, TYPE, BASENAME )  \
    NAME::NAME(KJS::ExecState *exec, const char* typeName ) \
        : BASENAME( exec, typeName )                    \
    { \
        StaticBinding::publish( exec, this, NAME::methods() ); \
    } \
    NAME::NAME(KJS::ExecState *exec, const TYPE & value)                \
        : BASENAME( exec, #JSNAME )                                         \
    {                                                                   \
        setValue(value);                                                \
        StaticBinding::publish( exec, this, NAME::methods() );          \
    }

namespace KJSEmbed
{
/**
 * The Bindings for the KJSEmbed::ValueBinding
 */
class ValueFactory
{
public:
    static const Method ValueMethods[];
    static const Method *methods();
};

/**
 * Value binding implementation.
 */
class ValueBinding : public ProxyBinding
{
public:
    template <typename T>
    ValueBinding(KJS::ExecState *exec, const char *typeName, T val)
        : ProxyBinding(exec),
          m_name(typeName)
    {
        m_value = new Value<T>(val);
        StaticBinding::publish(exec, this, ValueFactory::methods());
    }
    ValueBinding(KJS::ExecState *exec, const char *typeName);
    ~ValueBinding() override;

    KJS::UString toString(KJS::ExecState *exec) const override;
    KJS::UString className() const override
    {
        return m_name;
    }

    /**
    * Returns the stored value.
    */
    template< typename T>
    T value() const
    {
        const T *ptr = reinterpret_cast<const T *>(m_value->voidStar());
        if (ptr) {
            return *ptr;
        } else {
            return T();
        }
    }

    /**
    * Set the internal value.
    */
    template< typename T>
    void setValue(const T &val)
    {
        delete m_value;
        m_value = new Value<T>(val);
    }

    template< typename T>
    static T castValue(ValueBinding *imp)
    {
        const T *ptr = reinterpret_cast<const T *>(imp->m_value->voidStar());
        if (ptr) {
            return *ptr;
        } else {
            return T();
        }
    }
    static const KJS::ClassInfo info;

private:
    const KJS::ClassInfo *classInfo() const override
    {
        return &info;
    }

    PointerBase *m_value;
    const char *m_name;

};

/**
* Extracts a pointer based type from an ObjectBinding object.  Care should be taken that this method
* is not used with KJSEmbed::ObjectBinding objects because the cast will fail.
*/
template< typename T>
T extractValue(KJS::ExecState *exec, KJS::JSValue *arg, const T &defaultValue)
{
    if (arg) {
        KJSEmbed::ValueBinding *imp =
            KJSEmbed::extractBindingImp<KJSEmbed::ValueBinding>(exec, arg);
        if (imp) {
            return ValueBinding::castValue<T>(imp);
        }
    }
    return defaultValue;
}

/**
* Extracts a pointer from a KJS::List of KJS::Values.  If the argument is out of range the default value
* is returned.
*/
template< typename T>
T extractValue(KJS::ExecState *exec, const KJS::List &args, int idx, const T &defaultValue = T())
{
    if (args.size() > idx) {
        return extractValue<T>(exec, args[idx], defaultValue);
    } else {
        return defaultValue;
    }
}

template< typename T>
KJS::JSValue *createValue(KJS::ExecState *exec, const KJS::UString &className, const T &value)
{
    KJS::JSObject *parent = exec->dynamicInterpreter()->globalObject();
    KJS::JSObject *returnValue = StaticConstructor::construct(exec, parent, className);
    if (returnValue) {
        // If it is a value type setValue
        KJSEmbed::ValueBinding *imp =
            extractBindingImp<KJSEmbed::ValueBinding>(exec, returnValue);
        if (imp) {
            imp->setValue(value);
        } else {
            KJS::throwError(exec, KJS::TypeError, toUString(QString("Created failed to cast to %1 failed").arg(toQString(className))));
            return KJS::jsNull();
        }
    } else {
        KJS::throwError(exec, KJS::TypeError, toUString(QString("Could not construct a %1").arg(toQString(className))));
        return KJS::jsNull();
    }
    return returnValue;
}
}

#endif