Redcraft/Redcraft.Utility/Source/Public/Templates/ReferenceWrapper.h

231 lines
8.2 KiB
C++

#pragma once
#include "CoreTypes.h"
#include "Templates/Invoke.h"
#include "Templates/Utility.h"
#include "Templates/Optional.h"
#include "TypeTraits/TypeTraits.h"
NAMESPACE_REDCRAFT_BEGIN
NAMESPACE_MODULE_BEGIN(Redcraft)
NAMESPACE_MODULE_BEGIN(Utility)
template <typename ReferencedType> requires (TIsObject<ReferencedType>::Value || CFunction<ReferencedType>)
struct TReferenceWrapper
{
public:
using Type = ReferencedType;
template <typename T = ReferencedType> requires TIsConvertible<T, ReferencedType&>::Value
constexpr TReferenceWrapper(T&& Object) : Pointer(AddressOf(Forward<T>(Object))) { }
TReferenceWrapper(const TReferenceWrapper&) = default;
template <typename T = ReferencedType> requires TIsConvertible<T&, ReferencedType&>::Value
constexpr TReferenceWrapper(const TReferenceWrapper<T>& InValue)
: Pointer(InValue.Pointer)
{ }
TReferenceWrapper& operator=(const TReferenceWrapper&) = default;
template <typename T = ReferencedType> requires TIsConvertible<T&, ReferencedType&>::Value
constexpr TReferenceWrapper& operator=(const TReferenceWrapper<T>& InValue)
{
Pointer = InValue.Pointer;
return *this;
}
constexpr operator ReferencedType&() const { return *Pointer; }
constexpr ReferencedType& Get() const { return *Pointer; }
template <typename... Types>
constexpr TInvokeResult<ReferencedType&, Types...>::Type operator()(Types&&... Args) const
{
return Invoke(Get(), Forward<Types>(Args)...);
}
constexpr size_t GetTypeHash() const requires CHashable<ReferencedType>
{
return NAMESPACE_REDCRAFT::GetTypeHash(Get());
}
constexpr void Swap(TReferenceWrapper& InValue)
{
ReferencedType* Temp = Pointer;
Pointer = InValue.Pointer;
InValue.Pointer = Temp;
}
private:
ReferencedType* Pointer;
template <typename T> requires (TIsObject<T>::Value || CFunction<T>) friend struct TReferenceWrapper;
// Optimize TOptional with these hacking
constexpr TReferenceWrapper(FInvalid) : Pointer(nullptr) { };
template <typename T> requires TIsDestructible<T>::Value friend struct TOptional;
};
template <typename T>
TReferenceWrapper(T&) -> TReferenceWrapper<T>;
template <typename T>
void Ref(const T&&) = delete;
template <typename T>
constexpr TReferenceWrapper<T> Ref(T& InValue)
{
return TReferenceWrapper<T>(InValue);
}
template <typename T>
constexpr TReferenceWrapper<T> Ref(TReferenceWrapper<T> InValue)
{
return Ref(InValue.Get());
}
template <typename T>
constexpr TReferenceWrapper<const T> Ref(const T& InValue)
{
return TReferenceWrapper<const T>(InValue);
}
template <typename T>
constexpr TReferenceWrapper<const T> Ref(TReferenceWrapper<T> InValue)
{
return Ref(InValue.Get());
}
template <typename T> struct TIsTReferenceWrapper : FFalse { };
template <typename T> struct TIsTReferenceWrapper<TReferenceWrapper<T>> : FTrue { };
template <typename T> struct TUnwrapReference { using Type = T; };
template <typename T> struct TUnwrapReference<TReferenceWrapper<T>> { using Type = T&; };
template <typename T> struct TUnwrapRefDecay { using Type = typename TUnwrapReference<typename TDecay<T>::Type>::Type; };
template <typename ReferencedType>
struct TOptional<TReferenceWrapper<ReferencedType>>
{
private:
using OptionalType = TReferenceWrapper<ReferencedType>;
template <typename T>
struct TAllowUnwrapping : TBoolConstant<!(
TIsConstructible<OptionalType, TOptional<T>& >::Value
|| TIsConstructible<OptionalType, const TOptional<T>& >::Value
|| TIsConstructible<OptionalType, TOptional<T>&&>::Value
|| TIsConstructible<OptionalType, const TOptional<T>&&>::Value
|| TIsConvertible< TOptional<T>&, OptionalType>::Value
|| TIsConvertible<const TOptional<T>&, OptionalType>::Value
|| TIsConvertible< TOptional<T>&&, OptionalType>::Value
|| TIsConvertible<const TOptional<T>&&, OptionalType>::Value
|| TIsAssignable<OptionalType&, TOptional<T>& >::Value
|| TIsAssignable<OptionalType&, const TOptional<T>& >::Value
|| TIsAssignable<OptionalType&, TOptional<T>&&>::Value
|| TIsAssignable<OptionalType&, const TOptional<T>&&>::Value
)> { };
public:
using ValueType = OptionalType;
constexpr TOptional() : Reference(Invalid) { }
constexpr TOptional(FInvalid) : TOptional() { }
template <typename... Types> requires TIsConstructible<OptionalType, Types...>::Value
constexpr explicit TOptional(FInPlace, Types&&... Args)
: Reference(Forward<Types>(Args)...)
{ }
template <typename T = OptionalType> requires TIsConstructible<OptionalType, T&&>::Value
&& (!TIsSame<typename TRemoveCVRef<T>::Type, FInPlace>::Value) && (!TIsSame<typename TRemoveCVRef<T>::Type, TOptional>::Value)
constexpr explicit (!TIsConvertible<T&&, OptionalType>::Value) TOptional(T&& InValue)
: TOptional(InPlace, Forward<T>(InValue))
{ }
TOptional(const TOptional& InValue) = default;
TOptional(TOptional&& InValue) = default;
template <typename T = OptionalType> requires TIsConstructible<OptionalType, const T&>::Value && TAllowUnwrapping<T>::Value
constexpr explicit (!TIsConvertible<const T&, OptionalType>::Value) TOptional(const TOptional<T>& InValue)
: Reference(InValue.Reference)
{ }
~TOptional() = default;
TOptional& operator=(const TOptional& InValue) = default;
TOptional& operator=(TOptional&& InValue) = default;
template <typename T = OptionalType> requires TIsConstructible<OptionalType, const T&>::Value && TIsAssignable<OptionalType&, const T&>::Value && TAllowUnwrapping<T>::Value
constexpr TOptional& operator=(const TOptional<T>& InValue)
{
Reference = InValue.Reference;
return *this;
}
template <typename T = OptionalType> requires TIsConstructible<OptionalType, T&&>::Value && TIsAssignable<OptionalType&, T&&>::Value
constexpr TOptional& operator=(T&& InValue)
{
Reference = InValue;
return *this;
}
template <typename... ArgTypes> requires TIsConstructible<OptionalType, ArgTypes...>::Value
constexpr OptionalType& Emplace(ArgTypes&&... Args)
{
Reference = TReferenceWrapper<ReferencedType>(Forward<ArgTypes>(Args)...);
return Reference;
}
constexpr bool IsValid() const { return Reference.Pointer != nullptr; }
constexpr explicit operator bool() const { return Reference.Pointer != nullptr; }
constexpr OptionalType& GetValue() & { checkf(IsValid(), TEXT("It is an error to call GetValue() on an unset TOptional. Please either check IsValid() or use Get(DefaultValue) instead.")); return Reference; }
constexpr OptionalType&& GetValue() && { checkf(IsValid(), TEXT("It is an error to call GetValue() on an unset TOptional. Please either check IsValid() or use Get(DefaultValue) instead.")); return Reference; }
constexpr const OptionalType& GetValue() const& { checkf(IsValid(), TEXT("It is an error to call GetValue() on an unset TOptional. Please either check IsValid() or use Get(DefaultValue) instead.")); return Reference; }
constexpr const OptionalType&& GetValue() const&& { checkf(IsValid(), TEXT("It is an error to call GetValue() on an unset TOptional. Please either check IsValid() or use Get(DefaultValue) instead.")); return Reference; }
constexpr const OptionalType* operator->() const { return &GetValue(); }
constexpr OptionalType* operator->() { return &GetValue(); }
constexpr OptionalType& operator*() & { return GetValue(); }
constexpr OptionalType&& operator*() && { return GetValue(); }
constexpr const OptionalType& operator*() const& { return GetValue(); }
constexpr const OptionalType&& operator*() const&& { return GetValue(); }
constexpr OptionalType& Get( OptionalType& DefaultValue) & { return IsValid() ? GetValue() : DefaultValue; }
constexpr const OptionalType& Get(const OptionalType& DefaultValue) const& { return IsValid() ? GetValue() : DefaultValue; }
constexpr void Reset()
{
Reference = Invalid;
}
constexpr size_t GetTypeHash() const requires CHashable<ReferencedType>
{
if (!IsValid()) return 2824517378;
return Reference.GetTypeHash();
}
constexpr void Swap(TOptional& InValue)
{
Reference.Swap(InValue.Reference);
}
private:
TReferenceWrapper<ReferencedType> Reference;
template <typename T> requires TIsDestructible<T>::Value friend struct TOptional;
};
NAMESPACE_MODULE_END(Utility)
NAMESPACE_MODULE_END(Redcraft)
NAMESPACE_REDCRAFT_END