SlateAttributeDefinition.inl

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreMinimal.h"
#include "Misc/Attribute.h"
#include "Templates/EqualTo.h"
#include "Widgets/InvalidateWidgetReason.h"
 
#include <type_traits>
 
 
class SWidget;
 
namespace SlateAttributePrivate
{
    struct FSlateAttributeNoInvalidationReason
    {
        static constexpr EInvalidateWidgetReason GetInvalidationReason(const SWidget&) { return EInvalidateWidgetReason::None; }
    };
 
 
    enum class ESlateAttributeType : uint8
    {
        Member      = 0,    // Member of a SWidget (are not allowed to move).
        Managed     = 1,    // External to the SWidget, global variable or member that can moved.
        Contained       = 2,    // Inside a FSlot or other container that use dynamic memory (always attached to one and only one SWidget).
    };
 
 
    class ISlateAttributeGetter;
    template<typename ContainerType, typename ObjectType, typename InvalidationReasonPredicate, typename FComparePredicate, ESlateAttributeType AttributeType>
    struct TSlateAttributeBase;
    template<typename AttributeMemberType>
    struct TSlateMemberAttributeRef;
 
 
    class ISlateAttributeContainer
    {
    public:
        virtual SWidget& GetContainerWidget() const = 0;
        virtual FName GetContainerName() const = 0;
        virtual uint32 GetContainerSortOrder() const = 0;
 
    protected:
        SLATECORE_API void RemoveContainerWidget(SWidget& Widget);
        SLATECORE_API void UpdateContainerSortOrder(SWidget& Widget);
    };
 
 
    class ISlateAttributeGetter
    {
    public:
        struct FUpdateAttributeResult
        {
            FUpdateAttributeResult(EInvalidateWidgetReason InInvalidationReason)
                : InvalidationReason(InInvalidationReason)
                , bInvalidationRequested(true)
            {}
            FUpdateAttributeResult()
                : InvalidationReason(EInvalidateWidgetReason::None)
                , bInvalidationRequested(false)
            {}
            EInvalidateWidgetReason InvalidationReason;
            bool bInvalidationRequested;
        };
 
 
        virtual FUpdateAttributeResult UpdateAttribute(const SWidget& Widget) = 0;
        virtual const FSlateAttributeBase& GetAttribute() const = 0;
        virtual void SetAttribute(FSlateAttributeBase&) = 0;
        virtual FDelegateHandle GetDelegateHandle() const = 0;
        virtual ~ISlateAttributeGetter() = default;
    };
 
 
    struct FSlateAttributeImpl : public FSlateAttributeBase
    {
    protected:
        SLATECORE_API void ProtectedUnregisterAttribute(SWidget& Widget, ESlateAttributeType AttributeType) const;
        SLATECORE_API void ProtectedRegisterAttribute(SWidget& Widget, ESlateAttributeType AttributeType, TUniquePtr<ISlateAttributeGetter>&& Wrapper);
        SLATECORE_API void ProtectedInvalidateWidget(SWidget& Widget, ESlateAttributeType AttributeType, EInvalidateWidgetReason InvalidationReason) const;
        SLATECORE_API bool ProtectedIsBound(const SWidget& Widget, ESlateAttributeType AttributeType) const;
        SLATECORE_API ISlateAttributeGetter* ProtectedFindGetter(const SWidget& Widget, ESlateAttributeType AttributeType) const;
        SLATECORE_API FDelegateHandle ProtectedFindGetterHandle(const SWidget& Widget, ESlateAttributeType AttributeType) const;
        SLATECORE_API void ProtectedUpdateNow(SWidget& Widget, ESlateAttributeType AttributeType);
 
        //~ For Member
        SLATECORE_API bool ProtectedIsWidgetInDestructionPath(SWidget* Widget) const;
        SLATECORE_API bool ProtectedIsImplemented(const SWidget& Widget) const;
 
        //~ For Manage
        SLATECORE_API void ProtectedMoveAttribute(SWidget& Widget, ESlateAttributeType AttributeType, const FSlateAttributeBase* Other);
 
        //~ For Contain
        SLATECORE_API void ProtectedUnregisterAttribute(ISlateAttributeContainer& Widget, ESlateAttributeType AttributeType) const;
        SLATECORE_API void ProtectedRegisterAttribute(ISlateAttributeContainer& Widget, ESlateAttributeType AttributeType, TUniquePtr<ISlateAttributeGetter>&& Wrapper);
        SLATECORE_API void ProtectedInvalidateWidget(ISlateAttributeContainer& Widget, ESlateAttributeType AttributeType, EInvalidateWidgetReason InvalidationReason) const;
        SLATECORE_API bool ProtectedIsBound(const ISlateAttributeContainer& Widget, ESlateAttributeType AttributeType) const;
        SLATECORE_API ISlateAttributeGetter* ProtectedFindGetter(const ISlateAttributeContainer& Widget, ESlateAttributeType AttributeType) const;
        SLATECORE_API FDelegateHandle ProtectedFindGetterHandle(const ISlateAttributeContainer& Widget, ESlateAttributeType AttributeType) const;
        SLATECORE_API void ProtectedUpdateNow(ISlateAttributeContainer& Widget, ESlateAttributeType AttributeType);
    };
 
} // SlateAttributePrivate