368 lines
12 KiB
C
368 lines
12 KiB
C
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// Copyright Epic Games, Inc. All Rights Reserved.
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/*=============================================================================
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WeakFieldPtr.h: Weak pointer to FField
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=============================================================================*/
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#pragma once
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#include "UObject/WeakObjectPtrTemplates.h"
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#include "UObject/WeakObjectPtr.h"
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#include "UObject/FieldPath.h"
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template <class T>
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struct TWeakFieldPtr
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{
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private:
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// These exists only to disambiguate the two constructors below
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enum EDummy1
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{
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Dummy1
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};
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TWeakObjectPtr<UObject> Owner;
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mutable TFieldPath<T> Field;
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public:
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TWeakFieldPtr() = default;
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TWeakFieldPtr(const TWeakFieldPtr&) = default;
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TWeakFieldPtr& operator=(const TWeakFieldPtr&) = default;
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~TWeakFieldPtr() = default;
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/**
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* Construct from a null pointer
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**/
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FORCEINLINE TWeakFieldPtr(TYPE_OF_NULLPTR)
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: Owner((UObject*)nullptr), Field()
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{
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}
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/**
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* Construct from an object pointer
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* @param Object object to create a weak pointer to
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**/
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template <
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typename U,
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typename = decltype(ImplicitConv<T*>((U*)nullptr))>
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FORCEINLINE TWeakFieldPtr(U* InField, EDummy1 = Dummy1)
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: Owner(InField ? InField -> GetOwnerUObject() : (UObject*)nullptr), Field(InField)
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{
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// This static assert is in here rather than in the body of the class because we want
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// to be able to define TWeakFieldPtr<UUndefinedClass>.
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static_assert(TPointerIsConvertibleFromTo<T, const volatile FField>::Value, "TWeakFieldPtr can only be constructed with FField types");
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}
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/**
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* Construct from another weak pointer of another type, intended for derived-to-base conversions
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* @param Other weak pointer to copy from
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**/
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template <typename OtherT>
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FORCEINLINE TWeakFieldPtr(const TWeakFieldPtr<OtherT>& Other)
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: Owner(Other.Owner), Field(Other.Field)
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{
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// It's also possible that this static_assert may fail for valid conversions because
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// one or both of the types have only been forward-declared.
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static_assert(TPointerIsConvertibleFromTo<OtherT, T>::Value, "Unable to convert TWeakFieldPtr - types are incompatible");
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}
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/**
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* Reset the weak pointer back to the NULL state
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*/
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FORCEINLINE void Reset()
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{
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Owner.Reset();
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Field.Reset();
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}
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/**
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* Copy from an object pointer
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* @param Object object to create a weak pointer to
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**/
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template <class U>
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FORCEINLINE typename TEnableIf<!TLosesQualifiersFromTo<U, T>::Value>::Type operator=(const U* InField)
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{
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Owner = InField ? InField->GetOwnerUObject() : (UObject*)nullptr;
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Field = (U*)InField;
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}
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/**
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* Assign from another weak pointer, intended for derived-to-base conversions
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* @param Other weak pointer to copy from
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**/
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template <typename OtherT>
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FORCEINLINE void operator=(const TWeakFieldPtr<OtherT>& Other)
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{
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// It's also possible that this static_assert may fail for valid conversions because
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// one or both of the types have only been forward-declared.
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static_assert(TPointerIsConvertibleFromTo<OtherT, T>::Value, "Unable to convert TWeakFieldPtr - types are incompatible");
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Owner = Other.Owner;
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Field = Other.Field;
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}
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/**
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* Dereference the weak pointer
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* @param bEvenIfPendingKill, if this is true, pendingkill objects are considered valid
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* @return NULL if this object is gone or the weak pointer was NULL, otherwise a valid uobject pointer
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**/
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FORCEINLINE T* Get(bool bEvenIfPendingKill) const
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{
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if (Owner.Get(bEvenIfPendingKill))
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{
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return Field.Get();
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}
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else
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{
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// Clear potentially stale pointer to the actual field
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Field.ClearCachedField();
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}
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return nullptr;
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}
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/**
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* Dereference the weak pointer. This is an optimized version implying bEvenIfPendingKill=false.
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*/
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FORCEINLINE T* Get(/*bool bEvenIfPendingKill = false*/) const
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{
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if (Owner.Get())
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{
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return Field.Get();
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}
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else
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{
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// Clear potentially stale pointer to the actual field
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Field.ClearCachedField();
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}
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return nullptr;
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}
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/** Deferences the weak pointer even if its marked RF_Unreachable. This is needed to resolve weak pointers during GC (such as ::AddReferenceObjects) */
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FORCEINLINE T* GetEvenIfUnreachable() const
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{
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if (Owner.GetEvenIfUnreachable())
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{
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return Field.Get();
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}
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else
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{
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// Clear potentially stale pointer to the actual field
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Field.ClearCachedField();
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}
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return nullptr;
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}
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/**
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* Dereference the weak pointer
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**/
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FORCEINLINE T& operator*() const
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{
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return *Get();
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}
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/**
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* Dereference the weak pointer
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**/
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FORCEINLINE T* operator->() const
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{
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return Get();
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}
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/**
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* Test if this points to a live FField
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* @param bEvenIfPendingKill, if this is true, pendingkill objects are considered valid
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* @param bThreadsafeTest, if true then function will just give you information whether referenced
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* FField is gone forever (@return false) or if it is still there (@return true, no object flags checked).
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* @return true if Get() would return a valid non-null pointer
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**/
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FORCEINLINE bool IsValid(bool bEvenIfPendingKill, bool bThreadsafeTest = false) const
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{
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return Owner.IsValid(bEvenIfPendingKill, bThreadsafeTest) && Field.Get();
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}
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/**
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* Test if this points to a live FField. This is an optimized version implying bEvenIfPendingKill=false, bThreadsafeTest=false.
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* @return true if Get() would return a valid non-null pointer
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*/
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FORCEINLINE bool IsValid(/*bool bEvenIfPendingKill = false, bool bThreadsafeTest = false*/) const
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{
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return Owner.IsValid() && Field.Get();
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}
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/**
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* Slightly different than !IsValid(), returns true if this used to point to a FField, but doesn't any more and has not been assigned or reset in the mean time.
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* @param bIncludingIfPendingKill, if this is true, pendingkill objects are considered stale
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* @param bThreadsafeTest, set it to true when testing outside of Game Thread. Results in false if WeakObjPtr point to an existing object (no flags checked)
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* @return true if this used to point at a real object but no longer does.
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**/
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FORCEINLINE bool IsStale(bool bIncludingIfPendingKill = false, bool bThreadsafeTest = false) const
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{
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return Owner.IsStale(bIncludingIfPendingKill, bThreadsafeTest);
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}
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FORCEINLINE bool HasSameIndexAndSerialNumber(const TWeakFieldPtr& Other) const
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{
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return Owner.HasSameIndexAndSerialNumber(Other.Owner);
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}
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/** Hash function. */
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FORCEINLINE friend uint32 GetTypeHash(const TWeakFieldPtr& WeakObjectPtr)
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{
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return GetTypeHash(WeakObjectPtr.Field);
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}
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friend FArchive& operator<<(FArchive& Ar, TWeakFieldPtr& InWeakFieldPtr)
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{
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Ar << InWeakFieldPtr.Owner;
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Ar << InWeakFieldPtr.Field;
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return Ar;
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}
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/**
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* Compare weak pointers for equality
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* @param Other weak pointer to compare to
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**/
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template <typename TOther>
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FORCEINLINE bool operator==(const TWeakFieldPtr<TOther>& Other) const
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{
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static_assert(TPointerIsConvertibleFromTo<TOther, FField>::Value, "TWeakFieldPtr can only be compared with FField types");
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static_assert(TPointerIsConvertibleFromTo<T, TOther>::Value, "Unable to compare TWeakFieldPtr with raw pointer - types are incompatible");
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return Field == Other.Field;
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}
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/**
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* Compare weak pointers for inequality
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* @param Other weak pointer to compare to
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**/
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template <typename TOther>
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FORCEINLINE bool operator!=(const TWeakFieldPtr<TOther>& Other) const
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{
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static_assert(TPointerIsConvertibleFromTo<TOther, FField>::Value, "TWeakFieldPtr can only be compared with FField types");
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static_assert(TPointerIsConvertibleFromTo<T, TOther>::Value, "Unable to compare TWeakFieldPtr with raw pointer - types are incompatible");
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return Field != Other.Field;
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}
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/**
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* Compare weak pointers for equality
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* @param Other pointer to compare to
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**/
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template <typename TOther>
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FORCEINLINE bool operator==(const TOther* Other) const
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{
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static_assert(TPointerIsConvertibleFromTo<TOther, FField>::Value, "TWeakFieldPtr can only be compared with FField types");
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static_assert(TPointerIsConvertibleFromTo<T, TOther>::Value, "Unable to compare TWeakFieldPtr with raw pointer - types are incompatible");
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return Field == Other;
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}
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/**
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* Compare weak pointers for inequality
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* @param Other pointer to compare to
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**/
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template <typename TOther>
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FORCEINLINE bool operator!=(const TOther* Other) const
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{
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static_assert(TPointerIsConvertibleFromTo<TOther, FField>::Value, "TWeakFieldPtr can only be compared with FField types");
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static_assert(TPointerIsConvertibleFromTo<T, TOther>::Value, "Unable to compare TWeakFieldPtr with raw pointer - types are incompatible");
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return Field != Other;
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}
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};
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// Helper function which deduces the type of the initializer
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template <typename T>
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FORCEINLINE TWeakFieldPtr<T> MakeWeakFieldPtr(T* Ptr)
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{
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return TWeakFieldPtr<T>(Ptr);
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}
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template <typename LhsT, typename RhsT>
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FORCENOINLINE bool operator==(const LhsT* Lhs, const TWeakFieldPtr<RhsT>& Rhs)
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{
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// It's also possible that these static_asserts may fail for valid conversions because
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// one or both of the types have only been forward-declared.
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static_assert(TPointerIsConvertibleFromTo<LhsT, FField>::Value, "TWeakFieldPtr can only be compared with FField types");
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static_assert(TPointerIsConvertibleFromTo<LhsT, RhsT>::Value || TPointerIsConvertibleFromTo<RhsT, LhsT>::Value, "Unable to compare TWeakFieldPtr with raw pointer - types are incompatible");
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return Rhs == Lhs;
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}
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template <typename LhsT>
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FORCENOINLINE bool operator==(const TWeakFieldPtr<LhsT>& Lhs, TYPE_OF_NULLPTR)
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{
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return !Lhs.IsValid();
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}
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template <typename RhsT>
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FORCENOINLINE bool operator==(TYPE_OF_NULLPTR, const TWeakFieldPtr<RhsT>& Rhs)
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{
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return !Rhs.IsValid();
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}
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template <typename LhsT, typename RhsT>
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FORCENOINLINE bool operator!=(const LhsT* Lhs, const TWeakFieldPtr<RhsT>& Rhs)
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{
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// It's also possible that these static_asserts may fail for valid conversions because
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// one or both of the types have only been forward-declared.
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static_assert(TPointerIsConvertibleFromTo<LhsT, FField>::Value, "TWeakFieldPtr can only be compared with FField types");
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static_assert(TPointerIsConvertibleFromTo<LhsT, RhsT>::Value || TPointerIsConvertibleFromTo<RhsT, LhsT>::Value, "Unable to compare TWeakFieldPtr with raw pointer - types are incompatible");
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return Rhs != Lhs;
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}
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template <typename LhsT>
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FORCENOINLINE bool operator!=(const TWeakFieldPtr<LhsT>& Lhs, TYPE_OF_NULLPTR)
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{
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return Lhs.IsValid();
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}
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template <typename RhsT>
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FORCENOINLINE bool operator!=(TYPE_OF_NULLPTR, const TWeakFieldPtr<RhsT>& Rhs)
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{
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return Rhs.IsValid();
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}
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template <class T>
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struct TIsPODType<TWeakFieldPtr<T>>
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{
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enum
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{
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Value = true
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};
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};
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template <class T>
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struct TIsZeroConstructType<TWeakFieldPtr<T>>
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{
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enum
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{
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Value = true
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};
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};
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template <class T>
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struct TIsWeakPointerType<TWeakFieldPtr<T>>
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{
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enum
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{
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Value = true
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};
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};
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/**
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* MapKeyFuncs for TWeakFieldPtrs which allow the key to become stale without invalidating the map.
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*/
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template <typename KeyType, typename ValueType, bool bInAllowDuplicateKeys = false>
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struct TWeakFieldPtrMapKeyFuncs: public TDefaultMapKeyFuncs<KeyType, ValueType, bInAllowDuplicateKeys>
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{
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typedef typename TDefaultMapKeyFuncs<KeyType, ValueType, bInAllowDuplicateKeys>::KeyInitType KeyInitType;
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static FORCEINLINE bool Matches(KeyInitType A, KeyInitType B)
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{
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return A == B;
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}
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static FORCEINLINE uint32 GetKeyHash(KeyInitType Key)
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{
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return GetTypeHash(Key);
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}
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};
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