FieldNotificationDelegate.h

Go to the documentation of this file.

// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Algo/BinarySearch.h"
#include "Containers/Array.h"
#include "Containers/BitArray.h"
#include "CoreMinimal.h"
#include "Delegates/Delegate.h"
#include "FieldNotificationId.h"
#include "INotifyFieldValueChanged.h"
#include "Templates/IdentityFunctor.h"
#include "Templates/Less.h"
#include "Templates/UnrealTemplate.h"
#include "UObject/NameTypes.h"
#include "UObject/WeakObjectPtr.h"
 
#include <limits>
 
class UObject;
 
namespace UE::FieldNotification
{
    
class FFieldMulticastDelegate
{
public:
    using FDelegate = INotifyFieldValueChanged::FFieldValueChangedDelegate;
    using FDynamicDelegate = FFieldValueChangedDynamicDelegate;
 
private:
    struct FInvocationKey
    {
        TWeakObjectPtr<const UObject> Object;
        FFieldId Id;
        FName DynamicName;
        bool operator<(const FInvocationKey& Element) const
        {
            return Id.GetName().FastLess(Element.Id.GetName());
        }
    };
 
    struct FInvocationElement
    {
        FInvocationKey Key;
        FDelegate Delegate;
        bool operator<(const FInvocationElement& InElement) const
        {
            return Key < InElement.Key;
        }
    };
 
    friend bool operator<(const FInvocationElement& A, const FInvocationKey& B)
    {
        return A.Key < B;
    }
    friend bool operator<(const FInvocationKey& A, const FInvocationElement& B)
    {
        return A < B.Key;
    }
    friend bool operator<(const FInvocationElement& A, const FFieldId& B)
    {
        return A.Key.Id.GetName().FastLess(B.GetName());
    }
    friend bool operator<(const FFieldId& A, const FInvocationElement& B)
    {
        return A.GetName().FastLess(B.Key.Id.GetName());
    }
 
    using InvocationListType = TArray<FInvocationElement>;
 
public:
    FIELDNOTIFICATION_API FDelegateHandle Add(const UObject* InObject, FFieldId InFieldId, FDelegate InNewDelegate);
    FIELDNOTIFICATION_API FDelegateHandle Add(const UObject* InObject, FFieldId InFieldId, const FDynamicDelegate& InDynamicDelegate);
 
    struct FRemoveResult
    {
        bool bRemoved = false;
        bool bHasOtherBoundDelegates = false;
        const UObject* Object = nullptr;
        FFieldId FieldId;
    };
    FIELDNOTIFICATION_API FRemoveResult Remove(FDelegateHandle InDelegate);
    FIELDNOTIFICATION_API FRemoveResult Remove(const FDynamicDelegate& InDynamicDelegate);
 
    struct FRemoveFromResult
    {
        bool bRemoved = false;
        bool bHasOtherBoundDelegates = false;
    };
    FIELDNOTIFICATION_API FRemoveFromResult RemoveFrom(const UObject* InObject, FFieldId InFieldId, FDelegateHandle InDelegate);
    FIELDNOTIFICATION_API FRemoveFromResult RemoveFrom(const UObject* InObject, FFieldId InFieldId, const FDynamicDelegate& InDynamicDelegate);
 
    struct FRemoveAllResult
    {
        int32 RemoveCount = 0;
        TBitArray<> HasFields;
    };
    FIELDNOTIFICATION_API FRemoveAllResult RemoveAll(const UObject* InObject, FDelegateUserObjectConst InUserObject);
    FIELDNOTIFICATION_API FRemoveAllResult RemoveAll(const UObject* InObject, FFieldId InFieldId, FDelegateUserObjectConst InUserObject);
 
    FIELDNOTIFICATION_API void Broadcast(UObject* InObject, FFieldId InFieldId);
 
    FIELDNOTIFICATION_API void Reset();
 
    struct FDelegateView
    {
        FDelegateView(const UObject* InKeyObj, FFieldId InKeyId, const UObject* InObj, FName InFunction)
            : KeyObject(InKeyObj), KeyField(InKeyId), BindingObject(InObj), BindingFunctionName(InFunction)
        {}
        const UObject* KeyObject;
        FFieldId KeyField;
        const UObject* BindingObject;
        FName BindingFunctionName;
    };
    FIELDNOTIFICATION_API TArray<FDelegateView> GetView() const;
 
private:
    int32 LowerBound(FFieldId InFieldId) const
    {
        int32 Num = AddedEmplaceAt > GetNum(Delegates) ? GetNum(Delegates) : AddedEmplaceAt;
        return AlgoImpl::LowerBoundInternal(GetData(Delegates), Num, InFieldId, FIdentityFunctor(), TLess<>());
    }
 
    int32 LowerBound(const FInvocationKey& InKey) const
    {
        int32 Num = AddedEmplaceAt > GetNum(Delegates) ? GetNum(Delegates) : AddedEmplaceAt;
        return AlgoImpl::LowerBoundInternal(GetData(Delegates), Num, InKey, FIdentityFunctor(), TLess<>());
    }
 
    int32 UpperBound(FFieldId InFieldId) const
    {
        int32 Num = AddedEmplaceAt > GetNum(Delegates) ? GetNum(Delegates) : AddedEmplaceAt;
        return AlgoImpl::UpperBoundInternal(GetData(Delegates), Num, InFieldId, FIdentityFunctor(), TLess<>());
    }
 
    int32 UpperBound(const FInvocationKey& InKey) const
    {
        int32 Num = AddedEmplaceAt > GetNum(Delegates) ? GetNum(Delegates) : AddedEmplaceAt;
        return AlgoImpl::UpperBoundInternal(GetData(Delegates), Num, InKey, FIdentityFunctor(), TLess<>());
    }
 
    void ExecuteLockOperations();
    void RemoveElement(FInvocationElement& Element, int32 Index, FRemoveResult& Result);
    void CompleteRemove(FRemoveResult& Result) const;
    template<typename TRemoveOrUnbind>
    void RemoveFrom(TRemoveOrUnbind& RemoveOrUnbind, FFieldId FieldId, bool& bFieldPresent);
 
private:
    InvocationListType Delegates;
    int16 DelegateLockCount = 0;
    int16 CompactionCount = 0;
    uint16 AddedEmplaceAt = std::numeric_limits<uint16>::max();
};
 
} //namespace