EM_Task/CoreUObject/Private/UObject/PropertyDelegate.cpp

// Copyright Epic Games, Inc. All Rights Reserved.

#include "CoreMinimal.h"
#include "UObject/ObjectMacros.h"
#include "UObject/Class.h"
#include "UObject/UnrealType.h"
#include "UObject/UnrealTypePrivate.h"
#include "UObject/PropertyHelper.h"
#include "UObject/LinkerPlaceholderFunction.h"
#include "Serialization/ArchiveUObjectFromStructuredArchive.h"

// WARNING: This should always be the last include in any file that needs it (except .generated.h)
#include "UObject/UndefineUPropertyMacros.h"

/*-----------------------------------------------------------------------------
        FDelegateProperty.
-----------------------------------------------------------------------------*/
IMPLEMENT_FIELD(FDelegateProperty)

#if WITH_EDITORONLY_DATA
FDelegateProperty::FDelegateProperty(UField* InField)
    : FDelegateProperty_Super(InField)
{
    UDelegateProperty* SourceProperty = CastChecked<UDelegateProperty>(InField);
    SignatureFunction                 = SourceProperty->SignatureFunction;
}
#endif  // WITH_EDITORONLY_DATA

void FDelegateProperty::PostDuplicate(const FField& InField)
{
    const FDelegateProperty& Source = static_cast<const FDelegateProperty&>(InField);
    SignatureFunction               = Source.SignatureFunction;
    Super::PostDuplicate(InField);
}

void FDelegateProperty::InstanceSubobjects(void* Data, void const* DefaultData, UObject* InOwner, FObjectInstancingGraph* InstanceGraph)
{
    for (int32 i = 0; i < ArrayDim; i++)
    {
        FScriptDelegate& DestDelegate = ((FScriptDelegate*)Data)[i];
        UObject* CurrentUObject       = DestDelegate.GetUObject();

        if (CurrentUObject)
        {
            UObject* Template = NULL;

            if (DefaultData)
            {
                FScriptDelegate& DefaultDelegate = ((FScriptDelegate*)DefaultData)[i];
                Template                         = DefaultDelegate.GetUObject();
            }

            UObject* NewUObject = InstanceGraph->InstancePropertyValue(Template, CurrentUObject, InOwner, HasAnyPropertyFlags(CPF_Transient), false, true);
            DestDelegate.BindUFunction(NewUObject, DestDelegate.GetFunctionName());
        }
    }
}

bool FDelegateProperty::Identical(const void* A, const void* B, uint32 PortFlags) const
{
    const FScriptDelegate* DA = (const FScriptDelegate*)A;
    const FScriptDelegate* DB = (const FScriptDelegate*)B;

    if (!DB)
    {
        return DA->GetFunctionName() == NAME_None;
    }

    if (DA->GetUObject() != DB->GetUObject())
    {
        return false;
    }

    if (DA->GetFunctionName() != DB->GetFunctionName())
    {
        return false;
    }

    return true;
}

void FDelegateProperty::SerializeItem(FStructuredArchive::FSlot Slot, void* Value, void const* Defaults) const
{
    Slot << *GetPropertyValuePtr(Value);
}

bool FDelegateProperty::NetSerializeItem(FArchive& Ar, UPackageMap* Map, void* Data, TArray<uint8>* MetaData) const
{
    // Do not allow replication of delegates, as there is no way to make this secure (it allows the execution of any function in any object, on the remote client/server)
    return 1;
}

FString FDelegateProperty::GetCPPType(FString* ExtendedTypeText /*=NULL*/, uint32 CPPExportFlags /*=0*/) const
{
    check(SignatureFunction);

    FString UnmangledFunctionName   = SignatureFunction->GetName().LeftChop(FString(HEADER_GENERATED_DELEGATE_SIGNATURE_SUFFIX).Len());
    const bool bBlueprintCppBackend = (0 != (CPPExportFlags & EPropertyExportCPPFlags::CPPF_BlueprintCppBackend));
    const bool bNative              = SignatureFunction->IsNative();
    if (bBlueprintCppBackend && bNative)
    {
        UStruct* StructOwner = Cast<UStruct>(SignatureFunction->GetOuter());
        if (StructOwner)
        {
            return FString::Printf(TEXT("%s%s::F%s"), StructOwner->GetPrefixCPP(), *StructOwner->GetName(), *UnmangledFunctionName);
        }
    }
    else
    {
        const bool NonNativeClassOwner = (SignatureFunction->GetOwnerClass() && !SignatureFunction->GetOwnerClass()->HasAnyClassFlags(CLASS_Native));
        if (bBlueprintCppBackend && NonNativeClassOwner)
        {
            // The name must be valid, this removes spaces, ?, etc from the user's function name. It could
            // be slightly shorter because the postfix ("__pf") is not needed here because we further post-
            // pend to the string. Normally the postfix is needed to make sure we don't mangle to a valid
            // identifier and collide:
            UnmangledFunctionName = UnicodeToCPPIdentifier(UnmangledFunctionName, false, TEXT(""));
            // the name must be unique
            const FString OwnerName                = UnicodeToCPPIdentifier(SignatureFunction->GetOwnerClass()->GetName(), false, TEXT(""));
            const FString NewUnmangledFunctionName = FString::Printf(TEXT("%s__%s"), *UnmangledFunctionName, *OwnerName);
            UnmangledFunctionName                  = NewUnmangledFunctionName;
        }
        if (0 != (CPPExportFlags & EPropertyExportCPPFlags::CPPF_CustomTypeName))
        {
            UnmangledFunctionName += TEXT("__SinglecastDelegate");
        }
    }
    return FString(TEXT("F")) + UnmangledFunctionName;
}

FString FDelegateProperty::GetCPPTypeForwardDeclaration() const
{
    return FString();
}

void FDelegateProperty::ExportTextItem(FString& ValueStr, const void* PropertyValue, const void* DefaultValue, UObject* Parent, int32 PortFlags, UObject* ExportRootScope) const
{
    if (0 != (PortFlags & PPF_ExportCpp))
    {
        ValueStr += TEXT("{}");
        return;
    }

    FScriptDelegate* ScriptDelegate = (FScriptDelegate*)PropertyValue;
    check(ScriptDelegate != NULL);
    bool bDelegateHasValue = ScriptDelegate->GetFunctionName() != NAME_None;
    ValueStr += FString::Printf(TEXT("%s.%s"),
                                ScriptDelegate->GetUObject() != NULL ? *ScriptDelegate->GetUObject()->GetName() : TEXT("(null)"),
                                *ScriptDelegate->GetFunctionName().ToString());
}

const TCHAR* FDelegateProperty::ImportText_Internal(const TCHAR* Buffer, void* PropertyValue, int32 PortFlags, UObject* Parent, FOutputDevice* ErrorText) const
{
    return DelegatePropertyTools::ImportDelegateFromText(*(FScriptDelegate*)PropertyValue, SignatureFunction, Buffer, Parent, ErrorText);
}

void FDelegateProperty::Serialize(FArchive& Ar)
{
    Super::Serialize(Ar);
    Ar << SignatureFunction;

#if USE_CIRCULAR_DEPENDENCY_LOAD_DEFERRING
    if (Ar.IsLoading() || Ar.IsObjectReferenceCollector())
    {
        if (auto PlaceholderFunc = Cast<ULinkerPlaceholderFunction>(SignatureFunction))
        {
            PlaceholderFunc->AddReferencingProperty(this);
        }
    }
#endif  // USE_CIRCULAR_DEPENDENCY_LOAD_DEFERRING
}

void FDelegateProperty::AddReferencedObjects(FReferenceCollector& Collector)
{
#if USE_CIRCULAR_DEPENDENCY_LOAD_DEFERRING
    if (SignatureFunction && !SignatureFunction->IsA<ULinkerPlaceholderFunction>())
#endif  // USE_CIRCULAR_DEPENDENCY_LOAD_DEFERRING
    {
        Collector.AddReferencedObject(SignatureFunction);
    }
    Super::AddReferencedObjects(Collector);
}

bool FDelegateProperty::SameType(const FProperty* Other) const
{
    return Super::SameType(Other) && (SignatureFunction == ((FDelegateProperty*)Other)->SignatureFunction);
}

void FDelegateProperty::BeginDestroy()
{
#if USE_CIRCULAR_DEPENDENCY_LOAD_DEFERRING
    if (auto PlaceholderFunc = Cast<ULinkerPlaceholderFunction>(SignatureFunction))
    {
        PlaceholderFunc->RemoveReferencingProperty(this);
    }
#endif  // USE_CIRCULAR_DEPENDENCY_LOAD_DEFERRING

    Super::BeginDestroy();
}

#include "UObject/DefineUPropertyMacros.h"