Files
pilotclient/src/blackmisc/variant_private.h
2015-05-17 20:29:10 +02:00

236 lines
13 KiB
C++

/* Copyright (C) 2014
* swift project Community / Contributors
*
* This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
* directory of this distribution and at http://www.swift-project.org/license.html. No part of swift project,
* including this file, may be copied, modified, propagated, or distributed except according to the terms
* contained in the LICENSE file.
*/
//! \file
#ifndef BLACKMISC_VARIANT_PRIVATE_H
#define BLACKMISC_VARIANT_PRIVATE_H
#include "blackmisc/blackmiscexport.h"
#include "blackmisc/blackmiscfreefunctions.h"
#include "blackmisc/inheritance_traits.h"
#include <QString>
#include <QMetaType>
#include <QDBusMetaType>
#include <QDBusArgument>
#include <QJsonObject>
#include <stdexcept>
namespace BlackMisc
{
class CEmpty;
class CVariant;
class CPropertyIndex;
class CIcon;
template <typename T>
void registerMetaValueType();
namespace Private
{
//! \private Needed so we can copy forward-declared CVariant.
void assign(CVariant &, const CVariant &);
//! \private Needed so we can copy forward-declared CIcon.
void assign(CIcon &, const CIcon &);
//! \private Abstract base class representing the set of operations supported by a particular value type.
struct BLACKMISC_EXPORT IValueObjectMetaInfo
{
virtual ~IValueObjectMetaInfo() = default;
virtual QString toQString(const void *object, bool i18n) const = 0;
virtual QJsonObject toJson(const void *object) const = 0;
virtual void convertFromJson(const QJsonObject &json, void *object) const = 0;
virtual void unmarshall(const QDBusArgument &arg, void *object) const = 0;
virtual uint getValueHash(const void *object) const = 0;
virtual int getMetaTypeId() const = 0;
virtual const void *upCastTo(const void *object, int metaTypeId) const = 0;
virtual int compareImpl(const void *lhs, const void *rhs) const = 0;
virtual void setPropertyByIndex(void *object, const CVariant &variant, const CPropertyIndex &index) const = 0;
virtual void propertyByIndex(const void *object, CVariant &o_variant, const BlackMisc::CPropertyIndex &index) const = 0;
virtual QString propertyByIndexAsString(const void *object, const CPropertyIndex &index, bool i18n) const = 0;
virtual bool equalsPropertyByIndex(const void *object, const CVariant &compareValue, const CPropertyIndex &index) const = 0;
virtual void toIcon(const void *object, CIcon &o_icon) const = 0;
};
//! \private Exception to signal that an unsupported operation was requested.
class CVariantException : public std::invalid_argument
{
public:
template <class T>
CVariantException(const T &, const QString &operationName) : std::invalid_argument((blurb<T>(operationName)).toStdString()), m_operationName(operationName) {}
const QString &operationName() const { return m_operationName; }
~CVariantException() Q_DECL_NOEXCEPT {}
private:
QString m_operationName;
template <class T>
static QString blurb(const QString &operationName)
{
return QString("CVariant requested unsupported operation of contained ") + QMetaType::typeName(qMetaTypeId<T>()) + " object: " + operationName;
}
};
//! \private
namespace Fallback
{
//! \private Fallback in case qHash is not defined for T.
template <typename T>
uint qHash(const T &object) { throw CVariantException(object, "qHash"); }
//! \private Fallback in case compare is not defined for T.
template <typename T>
int compare(const T &a, const T &) { throw CVariantException(a, "compare"); }
}
//! \private Implementation of IValueObjectMetaInfo representing the set of operations supported by T.
template <typename T>
struct CValueObjectMetaInfo : public IValueObjectMetaInfo
{
//! \cond PRIVATE
// http://en.wikibooks.org/wiki/More_C++_Idioms/Member_Detector
struct Fallback { int toJson, convertFromJson, setPropertyByIndex, propertyByIndex, propertyByIndexAsString, equalsPropertyByIndex, toIcon; };
template <int Fallback::*> struct int_t { typedef int type; };
template <typename U> struct Derived : public U, public Fallback {};
# define DISABLE_IF_HAS(MEMBER) typename int_t<&Derived<U>::MEMBER>::type
//! \endcond
template <typename U> static QJsonObject toJsonHelper(const U &object, DISABLE_IF_HAS(toJson)) { throw CVariantException(object, "toJson"); }
template <typename U> static QJsonObject toJsonHelper(const U &object, ...) { return object.toJson(); }
template <typename U> static void convertFromJsonHelper(const QJsonObject &, U &object, DISABLE_IF_HAS(convertFromJson)) { throw CVariantException(object, "convertFromJson"); }
template <typename U> static void convertFromJsonHelper(const QJsonObject &json, U &object, ...) { object.convertFromJson(json); }
template <typename U> static void setPropertyByIndexHelper(U &object, const CVariant &, const CPropertyIndex &, DISABLE_IF_HAS(setPropertyByIndex)) { throw CVariantException(object, "setPropertyByIndex"); }
template <typename U> static void setPropertyByIndexHelper(U &object, const CVariant &variant, const CPropertyIndex &index, ...) { object.setPropertyByIndex(variant, index); }
template <typename U> static void propertyByIndexHelper(CVariant &, const U &object, const CPropertyIndex &, DISABLE_IF_HAS(propertyByIndex)) { throw CVariantException(object, "propertyByIndex"); }
template <typename U> static void propertyByIndexHelper(CVariant &o_variant, const U &object, const CPropertyIndex &index, ...) { assign(o_variant, object.propertyByIndex(index)); }
template <typename U> static QString propertyByIndexAsStringHelper(const U &object, const CPropertyIndex &, bool, DISABLE_IF_HAS(propertyByIndexAsString)) { throw CVariantException(object, "propertyByIndexAsString"); }
template <typename U> static QString propertyByIndexAsStringHelper(const U &object, const CPropertyIndex &index, bool i18n, ...) { return object.propertyByIndexAsString(index, i18n); }
template <typename U> static bool equalsPropertyByIndexHelper(const U &object, const CVariant &, const CPropertyIndex &, DISABLE_IF_HAS(equalsPropertyByIndex)) { throw CVariantException(object, "equalsPropertyByIndex"); }
template <typename U> static bool equalsPropertyByIndexHelper(const U &object, const CVariant &variant, const CPropertyIndex &index, ...) { return object.equalsPropertyByIndex(variant, index); }
template <typename U> static void toIconHelper(const U &object, CIcon &, DISABLE_IF_HAS(toIcon)) { throw CVariantException(object, "toIcon"); }
template <typename U> static void toIconHelper(const U &object, CIcon &, typename std::enable_if<std::is_same<U, CVariant>::value, int>::type) { throw CVariantException(object, "toIcon"); } // CIcon is incomplete when CValueObjectMetaInfo<CVariant> is instantiated
template <typename U> static void toIconHelper(const U &object, CIcon &o_icon, ...) { assign(o_icon, object.toIcon()); }
# undef DISABLE_IF_HAS
virtual QString toQString(const void *object, bool i18n) const override
{
return cast(object).toQString(i18n);
}
virtual QJsonObject toJson(const void *object) const override
{
return toJsonHelper(cast(object), 0);
}
virtual void convertFromJson(const QJsonObject &json, void *object) const override
{
convertFromJsonHelper(json, cast(object), 0);
}
virtual void unmarshall(const QDBusArgument &arg, void *object) const override
{
arg >> cast(object);
}
virtual uint getValueHash(const void *object) const override
{
using Private::Fallback::qHash;
return qHash(cast(object));
}
virtual int getMetaTypeId() const override
{
return maybeGetMetaTypeId(std::integral_constant<bool, QMetaTypeId<T>::Defined> {});
}
virtual const void *upCastTo(const void *object, int metaTypeId) const override
{
const auto base = static_cast<const void *>(static_cast<const MetaBaseOfT<T> *>(&cast(object)));
return metaTypeId == getMetaTypeId() ? object : CValueObjectMetaInfo<MetaBaseOfT<T>> {} .upCastTo(base, metaTypeId);
}
virtual int compareImpl(const void *lhs, const void *rhs) const override
{
using Private::Fallback::compare;
return compare(cast(lhs), cast(rhs));
}
virtual void setPropertyByIndex(void *object, const CVariant &variant, const CPropertyIndex &index) const override
{
setPropertyByIndexHelper(cast(object), variant, index, 0);
}
virtual void propertyByIndex(const void *object, CVariant &o_variant, const BlackMisc::CPropertyIndex &index) const override
{
propertyByIndexHelper(o_variant, cast(object), index, 0);
}
virtual QString propertyByIndexAsString(const void *object, const CPropertyIndex &index, bool i18n) const override
{
return propertyByIndexAsStringHelper(cast(object), index, i18n, 0);
}
virtual bool equalsPropertyByIndex(const void *object, const CVariant &compareValue, const CPropertyIndex &index) const override
{
return equalsPropertyByIndexHelper(cast(object), compareValue, index, 0);
}
virtual void toIcon(const void *object, CIcon &o_icon) const override
{
toIconHelper(cast(object), o_icon, 0);
}
static const T &cast(const void *object) { return *static_cast<const T *>(object); }
static T &cast(void *object) { return *static_cast<T *>(object); }
static int maybeGetMetaTypeId(std::true_type) { return qMetaTypeId<T>(); }
static int maybeGetMetaTypeId(std::false_type) { return QMetaType::UnknownType; }
};
//! \private Explicit specialization for the terminating case of the recursive CValueObjectMetaInfo::upCastTo.
template <>
struct CValueObjectMetaInfo<void>
{
const void *upCastTo(const void *, int) const
{
return nullptr;
}
};
//! \private Getter to obtain the IValueObjectMetaInfo which was stored by BlackMisc::registerMetaValueType.
IValueObjectMetaInfo *getValueObjectMetaInfo(int typeId);
//! \private Getter to obtain the IValueObjectMetaInfo which was stored by BlackMisc::registerMetaValueType.
IValueObjectMetaInfo *getValueObjectMetaInfo(const QVariant &);
//! \private Getter to obtain the IValueObjectMetaInfo which was stored by BlackMisc::registerMetaValueType.
template <typename T>
IValueObjectMetaInfo *getValueObjectMetaInfo() { return getValueObjectMetaInfo(qMetaTypeId<T>()); }
//! \cond PRIVATE
template <typename T, bool IsRegisteredMetaType /* = true */>
struct MetaTypeHelperImpl
{
static Q_DECL_CONSTEXPR int maybeGetMetaTypeId() { return qMetaTypeId<T>(); }
static void maybeRegisterMetaType() { qRegisterMetaType<T>(); qDBusRegisterMetaType<T>(); registerMetaValueType<T>(); }
static QVariant maybeToQVariant(const T &obj) { return QVariant::fromValue(obj); }
static void maybeConvertFromQVariant(T &obj, const QVariant &var) { BlackMisc::setFromQVariant(&obj, var); }
};
template <typename T>
struct MetaTypeHelperImpl<T, /* IsRegisteredMetaType = */ false>
{
static Q_DECL_CONSTEXPR int maybeGetMetaTypeId() { return QMetaType::UnknownType; }
static void maybeRegisterMetaType() {}
static QVariant maybeToQVariant(const T &) { return {}; }
static void maybeConvertFromQVariant(T &, const QVariant &) {}
};
template <typename T>
using MetaTypeHelper = MetaTypeHelperImpl<T, QMetaTypeId<T>::Defined>;
//! \endcond
}
}
Q_DECLARE_METATYPE(BlackMisc::Private::IValueObjectMetaInfo *)
#endif