ArchiveSerializedPropertyChain.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Containers/Array.h"
 
/** Structure containing the stack of properties that are currently being serialized by an archive */
struct FArchiveSerializedPropertyChain
{
public:
    /** Default constructor */
    FArchiveSerializedPropertyChain()
        : SerializedPropertyChainUpdateCount(0)
#if WITH_EDITORONLY_DATA
        , EditorOnlyPropertyStack(0)
#endif
    {
    }
 
    /**
     * Push a property that is currently being serialized
     * 
     * @param InProperty            Pointer to the property that is currently being serialized
     * @param bIsEditorOnlyProperty True if the property is editor only (call FProperty::IsEditorOnlyProperty to work this out, as the archive can't since it can't access CoreUObject types)
     */
    void PushProperty(struct FProperty* InProperty, const bool bIsEditorOnlyProperty)
    {
        check(InProperty);
        SerializedPropertyChain.Push(InProperty);
 
        IncrementUpdateCount();
 
#if WITH_EDITORONLY_DATA
        if (bIsEditorOnlyProperty)
        {
            ++EditorOnlyPropertyStack;
        }
#endif
    }
 
    /**
     * Pop a property that was previously being serialized
     * 
     * @param InProperty            Pointer to the property that was previously being serialized
     * @param bIsEditorOnlyProperty True if the property is editor only (call FProperty::IsEditorOnlyProperty to work this out, as the archive can't since it can't access CoreUObject types)
     */
    void PopProperty(struct FProperty* InProperty, const bool bIsEditorOnlyProperty)
    {
        check(InProperty);
        check(SerializedPropertyChain.Num() > 0 && SerializedPropertyChain.Last() == InProperty);
        SerializedPropertyChain.Pop(/*bAllowShrinking*/false);
 
        IncrementUpdateCount();
 
#if WITH_EDITORONLY_DATA
        if (bIsEditorOnlyProperty)
        {
            --EditorOnlyPropertyStack;
            check(EditorOnlyPropertyStack >= 0);
        }
#endif
    }
 
    /**
     * Get the property at the given index on the stack
     * @note This index is in stack order, so the 0th index with be the leaf property on the stack
     */
    struct FProperty* GetPropertyFromStack(const int32 InStackIndex) const
    {
        return SerializedPropertyChain.Last(InStackIndex);
    }
 
    /**
     * Get the property at the given index from the root
     * @note This index is in array order, so the 0th index with be the root property on the stack
     */
    struct FProperty* GetPropertyFromRoot(const int32 InRootIndex) const
    {
        return SerializedPropertyChain[InRootIndex];
    }
 
    /**
     * Get the number of properties currently on the stack
     */
    int32 GetNumProperties() const
    {
        return SerializedPropertyChain.Num();
    }
 
    /**
     * Get the counter for the number of times that SerializedPropertyChain has been updated
     */
    uint32 GetUpdateCount() const
    {
        return SerializedPropertyChainUpdateCount;
    }
 
    /**
     * Check to see whether there are any editor-only properties on the stack
     */
    bool HasEditorOnlyProperty() const
    {
#if WITH_EDITORONLY_DATA
        return EditorOnlyPropertyStack > 0;
#else
        return false;
#endif
    }
 
private:
    void IncrementUpdateCount()
    {
        while (++SerializedPropertyChainUpdateCount == 0) {} // Zero is special, don't allow an overflow to stay at zero
    }
 
    /** Array of properties on the stack */
    TArray<struct FProperty*, TInlineAllocator<8>> SerializedPropertyChain;
 
    /** Counter for the number of times that SerializedPropertyChain has been updated */
    uint32 SerializedPropertyChainUpdateCount;
 
#if WITH_EDITORONLY_DATA
    /** Non-zero if on the current stack of serialized properties there's an editor-only property */
    int32 EditorOnlyPropertyStack;
#endif
};