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Diffstat (limited to 'src/httpserver/qhttpserverviewtraits_impl.h')
| -rw-r--r-- | src/httpserver/qhttpserverviewtraits_impl.h | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/src/httpserver/qhttpserverviewtraits_impl.h b/src/httpserver/qhttpserverviewtraits_impl.h new file mode 100644 index 0000000..45c46d7 --- /dev/null +++ b/src/httpserver/qhttpserverviewtraits_impl.h @@ -0,0 +1,194 @@ +/**************************************************************************** +** +** Copyright (C) 2020 Mikhail Svetkin <mikhail.svetkin@gmail.com> +** Copyright (C) 2019 The Qt Company Ltd. +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the QtHttpServer module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:GPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3 or (at your option) any later version +** approved by the KDE Free Qt Foundation. The licenses are as published by +** the Free Software Foundation and appearing in the file LICENSE.GPL3 +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#ifndef QHTTPSERVERVIEWTRAITS_IMPL_H +#define QHTTPSERVERVIEWTRAITS_IMPL_H + +#include <QtCore/qglobal.h> +#include <QtCore/qmetatype.h> +#include <QtCore/qnamespace.h> +#include <QtCore/qobjectdefs.h> + +#include <functional> +#include <tuple> +#include <type_traits> + +QT_BEGIN_NAMESPACE + +namespace QtPrivate { + +template<typename T> +struct RemoveCVRef +{ + using Type = typename std::remove_cv<typename std::remove_reference<T>::type>::type; +}; + + +template<bool classMember, typename ReturnT, typename ... Args> +struct FunctionTraitsHelper +{ + static constexpr const int ArgumentCount = sizeof ... (Args); + static constexpr const int ArgumentIndexMax = ArgumentCount - 1; + static constexpr const bool IsClassMember = classMember; + using ReturnType = ReturnT; + + template <int I> + struct Arg { + using Type = typename std::tuple_element<I, std::tuple<Args...>>::type; + + using CleanType = typename QtPrivate::RemoveCVRef<Type>::Type; + + static constexpr bool Defined = QMetaTypeId2<CleanType>::Defined; + }; +}; + +template<bool classMember, typename ReturnT> +struct FunctionTraitsHelper<classMember, ReturnT> +{ + static constexpr const int ArgumentCount = 0; + static constexpr const int ArgumentIndexMax = -1; + static constexpr const bool IsClassMember = classMember; + using ReturnType = ReturnT; + + template <int I> + struct Arg { + using Type = std::false_type; + using CleanType = Type; + static constexpr bool Defined = QMetaTypeId2<CleanType>::Defined; + }; +}; + +template<typename T> +struct FunctionTraits; + +template<typename T> +struct FunctionTraits : public FunctionTraits<decltype(&T::operator())>{}; + +template<typename ReturnT, typename ... Args> +struct FunctionTraits<ReturnT (*)(Args...)> + : public FunctionTraitsHelper<false, ReturnT, Args...> +{ +}; + +template<class ReturnT, class ClassT, class ...Args> +struct FunctionTraits<ReturnT (ClassT::*)(Args...) const> + : public FunctionTraitsHelper<true, ReturnT, Args...> +{ + using classType = ClassT; +}; + +struct StaticMath { + template <template<typename> class Predicate, bool defaultValue> + struct Loop { + static constexpr bool eval() noexcept { + return defaultValue; + } + + template<typename T, typename ... N> + static constexpr T eval(const T it, N ...n) noexcept { + return Predicate<T>::eval(it, eval(n...)); + } + }; + + template<typename T> + struct SumPredicate { + static constexpr T eval(const T rs, const T ls) noexcept + { + return rs + ls; + } + }; + + template<typename T> + struct AndPredicate { + static constexpr T eval(const T rs, const T ls) noexcept + { + return rs && ls; + } + }; + + using Sum = Loop<SumPredicate, false>; + using And = Loop<AndPredicate, true>; + using Or = Sum; +}; + +template<typename ... T> +struct CheckAny { + static constexpr bool Value = StaticMath::Or::eval(T::Value...); + static constexpr bool Valid = StaticMath::Or::eval(T::Valid...); + static constexpr bool StaticAssert = StaticMath::Or::eval(T::StaticAssert...); +}; + +template<typename ViewHandler, bool DisableStaticAssert> +struct ViewTraits { + using FTraits = FunctionTraits<ViewHandler>; + using ArgumentIndexes = typename Indexes<FTraits::ArgumentCount>::Value; + + template<int I, typename Special> + struct SpecialHelper { + using Arg = typename FTraits::template Arg<I>; + using CleanSpecialT = typename RemoveCVRef<Special>::Type; + + static constexpr bool TypeMatched = std::is_same<typename Arg::CleanType, CleanSpecialT>::value; + static constexpr bool TypeCVRefMatched = std::is_same<typename Arg::Type, Special>::value; + + static constexpr bool ValidPosition = + (I == FTraits::ArgumentIndexMax || + I == FTraits::ArgumentIndexMax - 1); + static constexpr bool ValidAll = TypeCVRefMatched && ValidPosition; + + static constexpr bool AssertCondition = + DisableStaticAssert || !TypeMatched || TypeCVRefMatched; + + static constexpr bool AssertConditionOrder = + DisableStaticAssert || !TypeMatched || ValidPosition; + + static constexpr bool StaticAssert = AssertCondition && AssertConditionOrder; + + static_assert(AssertConditionOrder, + "ViewHandler arguments error: " + "QHttpServerRequest or QHttpServerResponder" + " can only be the last argument"); + }; + + template<int I, typename T> + struct Special { + using Helper = SpecialHelper<I, T>; + static constexpr bool Value = Helper::TypeMatched; + static constexpr bool Valid = Helper::ValidAll; + static constexpr bool StaticAssert = Helper::StaticAssert; + static constexpr bool AssertCondition = Helper::AssertCondition; + }; +}; + +} // namespace QtPrivate + +QT_END_NAMESPACE + +#endif // QHTTPSERVERVIEWTRAITS_IMPL_H |