266 lines
9.3 KiB
C
266 lines
9.3 KiB
C
|
// Copyright Epic Games, Inc. All Rights Reserved.
|
||
|
|
|
||
|
|
/*=============================================================================
|
||
|
|
WeakObjectPtr.h: Weak pointer to UObject
|
||
|
|
=============================================================================*/
|
||
|
|
|
||
|
|
#pragma once
|
||
|
|
|
||
|
|
#include "CoreMinimal.h"
|
||
|
|
#include "UObject/UObjectArray.h"
|
||
|
|
#include "UObject/FastReferenceCollectorOptions.h"
|
||
|
|
|
||
|
|
/**
|
||
|
|
* FWeakObjectPtr is a weak pointer to a UObject.
|
||
|
|
* It can return nullptr later if the object is garbage collected.
|
||
|
|
* It has no impact on if the object is garbage collected or not.
|
||
|
|
* It can't be directly used across a network.
|
||
|
|
*
|
||
|
|
* Most often it is used when you explicitly do NOT want to prevent something from being garbage collected.
|
||
|
|
*/
|
||
|
|
struct FWeakObjectPtr
|
||
|
|
{
|
||
|
|
public:
|
||
|
|
template <typename ReferenceProcessorType, typename CollectorType, typename ArrayPoolType, EFastReferenceCollectorOptions Options>
|
||
|
|
friend class TFastReferenceCollector;
|
||
|
|
friend struct FFieldPath;
|
||
|
|
|
||
|
|
/** Null constructor **/
|
||
|
|
FORCEINLINE FWeakObjectPtr()
|
||
|
|
{
|
||
|
|
Reset();
|
||
|
|
}
|
||
|
|
/**
|
||
|
|
* Construct from an object pointer
|
||
|
|
* @param Object object to create a weak pointer to
|
||
|
|
*/
|
||
|
|
FORCEINLINE FWeakObjectPtr(const class UObject* Object)
|
||
|
|
{
|
||
|
|
(*this) = Object;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Construct from another weak pointer
|
||
|
|
* @param Other weak pointer to copy from
|
||
|
|
*/
|
||
|
|
FWeakObjectPtr(const FWeakObjectPtr& Other) = default;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Reset the weak pointer back to the null state
|
||
|
|
*/
|
||
|
|
FORCEINLINE void Reset()
|
||
|
|
{
|
||
|
|
ObjectIndex = INDEX_NONE;
|
||
|
|
ObjectSerialNumber = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Copy from an object pointer
|
||
|
|
* @param Object object to create a weak pointer to
|
||
|
|
*/
|
||
|
|
COREUOBJECT_API void operator=(const class UObject* Object);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Construct from another weak pointer
|
||
|
|
* @param Other weak pointer to copy from
|
||
|
|
*/
|
||
|
|
FWeakObjectPtr& operator=(const FWeakObjectPtr& Other) = default;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Compare weak pointers for equality.
|
||
|
|
* If both pointers would return nullptr from Get() they count as equal even if they were not initialized to the same object.
|
||
|
|
* @param Other weak pointer to compare to
|
||
|
|
*/
|
||
|
|
FORCEINLINE bool operator==(const FWeakObjectPtr& Other) const
|
||
|
|
{
|
||
|
|
return (ObjectIndex == Other.ObjectIndex && ObjectSerialNumber == Other.ObjectSerialNumber) ||
|
||
|
|
(!IsValid() && !Other.IsValid());
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Compare weak pointers for inequality
|
||
|
|
* @param Other weak pointer to compare to
|
||
|
|
*/
|
||
|
|
FORCEINLINE bool operator!=(const FWeakObjectPtr& Other) const
|
||
|
|
{
|
||
|
|
return (ObjectIndex != Other.ObjectIndex || ObjectSerialNumber != Other.ObjectSerialNumber) &&
|
||
|
|
(IsValid() || Other.IsValid());
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns true if two weak pointers were originally set to the same object, even if they are now stale
|
||
|
|
* @param Other weak pointer to compare to
|
||
|
|
*/
|
||
|
|
FORCEINLINE bool HasSameIndexAndSerialNumber(const FWeakObjectPtr& Other) const
|
||
|
|
{
|
||
|
|
return ObjectIndex == Other.ObjectIndex && ObjectSerialNumber == Other.ObjectSerialNumber;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Dereference the weak pointer.
|
||
|
|
* @param bEvenIfPendingKill if this is true, pendingkill objects are considered valid
|
||
|
|
* @return nullptr if this object is gone or the weak pointer is explicitly null, otherwise a valid uobject pointer
|
||
|
|
*/
|
||
|
|
COREUOBJECT_API class UObject* Get(bool bEvenIfPendingKill) const;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Dereference the weak pointer. This is an optimized version implying bEvenIfPendingKill=false.
|
||
|
|
* @return nullptr if this object is gone or the weak pointer is explicitly null, otherwise a valid uobject pointer
|
||
|
|
*/
|
||
|
|
COREUOBJECT_API class UObject* Get(/*bool bEvenIfPendingKill = false*/) const;
|
||
|
|
|
||
|
|
/** Dereference the weak pointer even if it is RF_PendingKill or RF_Unreachable */
|
||
|
|
COREUOBJECT_API class UObject* GetEvenIfUnreachable() const;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Test if this points to a live UObject
|
||
|
|
* @param bEvenIfPendingKill if this is true, pendingkill are not considered invalid
|
||
|
|
* @param bThreadsafeTest if true then function will just give you information whether referenced
|
||
|
|
* UObject is gone forever (return false) or if it is still there (return true, no object flags checked).
|
||
|
|
* @return true if Get() would return a valid non-null pointer
|
||
|
|
*/
|
||
|
|
COREUOBJECT_API bool IsValid(bool bEvenIfPendingKill, bool bThreadsafeTest = false) const;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Test if this points to a live UObject. This is an optimized version implying bEvenIfPendingKill=false, bThreadsafeTest=false.
|
||
|
|
* @return true if Get() would return a valid non-null pointer.
|
||
|
|
*/
|
||
|
|
COREUOBJECT_API bool IsValid(/*bool bEvenIfPendingKill = false, bool bThreadsafeTest = false*/) const;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Slightly different than !IsValid(), returns true if this used to point to a UObject, but doesn't any more and has not been assigned or reset in the mean time.
|
||
|
|
* @param bIncludingIfPendingKill if this is false, pendingkill objects are not considered stale
|
||
|
|
* @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)
|
||
|
|
* @return true if this used to point at a real object but no longer does.
|
||
|
|
*/
|
||
|
|
COREUOBJECT_API bool IsStale(bool bIncludingIfPendingKill = true, bool bThreadsafeTest = false) const;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns true if this pointer was explicitly assigned to null, was reset, or was never initialized.
|
||
|
|
* If this returns true, IsValid() and IsStale() will both return false.
|
||
|
|
*/
|
||
|
|
FORCEINLINE bool IsExplicitlyNull() const
|
||
|
|
{
|
||
|
|
return ObjectIndex == INDEX_NONE;
|
||
|
|
}
|
||
|
|
|
||
|
|
/** Hash function. */
|
||
|
|
friend uint32 GetTypeHash(const FWeakObjectPtr& WeakObjectPtr)
|
||
|
|
{
|
||
|
|
return uint32(WeakObjectPtr.ObjectIndex ^ WeakObjectPtr.ObjectSerialNumber);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Weak object pointer serialization. Weak object pointers only have weak references to objects and
|
||
|
|
* won't serialize the object when gathering references for garbage collection. So in many cases, you
|
||
|
|
* don't need to bother serializing weak object pointers. However, serialization is required if you
|
||
|
|
* want to load and save your object.
|
||
|
|
*/
|
||
|
|
COREUOBJECT_API void Serialize(FArchive& Ar);
|
||
|
|
|
||
|
|
protected:
|
||
|
|
FORCEINLINE int32 GetObjectIndex() const
|
||
|
|
{
|
||
|
|
return ObjectIndex;
|
||
|
|
}
|
||
|
|
|
||
|
|
private:
|
||
|
|
friend struct FObjectKey;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* internal function to test for serial number matches
|
||
|
|
* @return true if the serial number in this matches the central table
|
||
|
|
*/
|
||
|
|
FORCEINLINE_DEBUGGABLE bool SerialNumbersMatch() const
|
||
|
|
{
|
||
|
|
checkSlow(ObjectSerialNumber > FUObjectArray::START_SERIAL_NUMBER && ObjectIndex >= 0); // otherwise this is a corrupted weak pointer
|
||
|
|
int32 ActualSerialNumber = GUObjectArray.GetSerialNumber(ObjectIndex);
|
||
|
|
checkSlow(!ActualSerialNumber || ActualSerialNumber >= ObjectSerialNumber); // serial numbers should never shrink
|
||
|
|
return ActualSerialNumber == ObjectSerialNumber;
|
||
|
|
}
|
||
|
|
|
||
|
|
FORCEINLINE_DEBUGGABLE bool SerialNumbersMatch(FUObjectItem* ObjectItem) const
|
||
|
|
{
|
||
|
|
checkSlow(ObjectSerialNumber > FUObjectArray::START_SERIAL_NUMBER && ObjectIndex >= 0); // otherwise this is a corrupted weak pointer
|
||
|
|
const int32 ActualSerialNumber = ObjectItem->GetSerialNumber();
|
||
|
|
checkSlow(!ActualSerialNumber || ActualSerialNumber >= ObjectSerialNumber); // serial numbers should never shrink
|
||
|
|
return ActualSerialNumber == ObjectSerialNumber;
|
||
|
|
}
|
||
|
|
|
||
|
|
FORCEINLINE FUObjectItem* Internal_GetObjectItem() const
|
||
|
|
{
|
||
|
|
if (ObjectSerialNumber == 0)
|
||
|
|
{
|
||
|
|
checkSlow(ObjectIndex == 0 || ObjectIndex == -1); // otherwise this is a corrupted weak pointer
|
||
|
|
return nullptr;
|
||
|
|
}
|
||
|
|
if (ObjectIndex < 0)
|
||
|
|
{
|
||
|
|
return nullptr;
|
||
|
|
}
|
||
|
|
FUObjectItem* const ObjectItem = GUObjectArray.IndexToObject(ObjectIndex);
|
||
|
|
if (!ObjectItem)
|
||
|
|
{
|
||
|
|
return nullptr;
|
||
|
|
}
|
||
|
|
if (!SerialNumbersMatch(ObjectItem))
|
||
|
|
{
|
||
|
|
return nullptr;
|
||
|
|
}
|
||
|
|
return ObjectItem;
|
||
|
|
}
|
||
|
|
|
||
|
|
/** Private (inlined) version for internal use only. */
|
||
|
|
FORCEINLINE_DEBUGGABLE bool Internal_IsValid(bool bEvenIfPendingKill, bool bThreadsafeTest) const
|
||
|
|
{
|
||
|
|
FUObjectItem* const ObjectItem = Internal_GetObjectItem();
|
||
|
|
if (bThreadsafeTest)
|
||
|
|
{
|
||
|
|
return (ObjectItem != nullptr);
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
return (ObjectItem != nullptr) && GUObjectArray.IsValid(ObjectItem, bEvenIfPendingKill);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/** Private (inlined) version for internal use only. */
|
||
|
|
FORCEINLINE_DEBUGGABLE UObject* Internal_Get(bool bEvenIfPendingKill) const
|
||
|
|
{
|
||
|
|
FUObjectItem* const ObjectItem = Internal_GetObjectItem();
|
||
|
|
return ((ObjectItem != nullptr) && GUObjectArray.IsValid(ObjectItem, bEvenIfPendingKill)) ? (UObject*)ObjectItem->Object : nullptr;
|
||
|
|
}
|
||
|
|
|
||
|
|
int32 ObjectIndex;
|
||
|
|
int32 ObjectSerialNumber;
|
||
|
|
};
|
||
|
|
|
||
|
|
template <>
|
||
|
|
struct TIsPODType<FWeakObjectPtr>
|
||
|
|
{
|
||
|
|
enum
|
||
|
|
{
|
||
|
|
Value = true
|
||
|
|
};
|
||
|
|
};
|
||
|
|
template <>
|
||
|
|
struct TIsZeroConstructType<FWeakObjectPtr>
|
||
|
|
{
|
||
|
|
enum
|
||
|
|
{
|
||
|
|
Value = true
|
||
|
|
};
|
||
|
|
};
|
||
|
|
template <>
|
||
|
|
struct TIsWeakPointerType<FWeakObjectPtr>
|
||
|
|
{
|
||
|
|
enum
|
||
|
|
{
|
||
|
|
Value = true
|
||
|
|
};
|
||
|
|
};
|
||
|
|
|
||
|
|
// Typedef script delegates for convenience.
|
||
|
|
typedef TScriptDelegate<> FScriptDelegate;
|
||
|
|
typedef TMulticastScriptDelegate<> FMulticastScriptDelegate;
|