CommonTypes.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "DataStorage/Handles.h"
 
#include "CommonTypes.generated.h"
 
USTRUCT()
struct FEditorDataStorageColumn
{
    GENERATED_BODY()
};
 
USTRUCT()
struct FEditorDataStorageTag
{
    GENERATED_BODY()
};
 
namespace UE
{
    // Work around missing header/implementations on some platforms
    namespace detail
    {
        template<typename T, typename U>
        concept SameHelper = std::is_same_v<T, U>;
    }
    template<typename T, typename U>
    concept same_as = detail::SameHelper<T, U> && detail::SameHelper<U, T>;
 
    template<typename From, typename To>
    concept convertible_to = std::is_convertible_v<From, To> && requires { static_cast<To>(std::declval<From>()); };
 
    template<typename Derived, typename Base>
    concept derived_from = std::is_base_of_v<Base, Derived> && std::is_convertible_v<const volatile Derived*, const volatile Base*>;
 
    namespace Editor::DataStorage
    {
        using FColumn = FEditorDataStorageColumn;
        using FTag = FEditorDataStorageTag;
 
        class FValueTag
        {
        public:
            TYPEDELEMENTFRAMEWORK_API explicit FValueTag(const FName& InName);
            
            TYPEDELEMENTFRAMEWORK_API const FName& GetName() const;
            bool operator==(const FValueTag& Other) const = default;
        private:
            TYPEDELEMENTFRAMEWORK_API friend uint32 GetTypeHash(const FValueTag& InName);
            FName Name;
        };
 
        template<typename T>
        concept TValueTagType = std::is_same_v<T, FValueTag>;
 
        struct FDynamicColumnDescription
        {
            const UScriptStruct* TemplateType;
            FName Identifier;
 
            TYPEDELEMENTFRAMEWORK_API friend uint32 GetTypeHash(const FDynamicColumnDescription& Descriptor);
            bool operator==(const FDynamicColumnDescription&) const = default;
        };
        // Standard callbacks.
 
        using RowCreationCallbackRef = TFunctionRef<void(RowHandle Row)>;
        using ColumnCreationCallbackRef = TFunctionRef<void(void* Column, const UScriptStruct& ColumnType)>;
        using ColumnListCallbackRef = TFunctionRef<void(const UScriptStruct& ColumnType)>;
        using ColumnListWithDataCallbackRef = TFunctionRef<void(void* Column, const UScriptStruct& ColumnType)>;
        using ColumnCopyOrMoveCallback = void (*)(const UScriptStruct& ColumnType, void* Destination, void* Source);
 
        template<typename T>
        concept THasDynamicColumnTemplateSpecifier = std::is_empty_v<typename T::EditorDataStorage_DynamicColumnTemplate>;
        
        template<typename T>
        concept TDynamicColumnTemplate = (UE::derived_from<T, FColumn> || UE::derived_from<T, FTag>) && THasDynamicColumnTemplateSpecifier<T>;
        
        // Template concepts to enforce type correctness.
        template<typename T>
        concept TDataColumnType = UE::derived_from<T, FColumn> && !THasDynamicColumnTemplateSpecifier<T>;
 
        template<typename T>
        concept TTagColumnType = UE::derived_from<T, FTag> && !THasDynamicColumnTemplateSpecifier<T>;
        
        template<typename T>
        concept TColumnType = TDataColumnType<T> || TTagColumnType<T>;
 
        template<typename T>
        concept TEnumType = std::is_enum_v<T>;
    } // namespace Editor::DataStorage
} // namespace UE