ObserverPointer.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "uLang/Common/Containers/SharedPointer.h"
#include "uLang/Common/Containers/UniquePointer.h"
 
#ifndef ULANG_CHECK_OBSERVER_POINTERS
    #define ULANG_CHECK_OBSERVER_POINTERS ULANG_DO_CHECK
#endif
 
namespace uLang
{
 
#if ULANG_CHECK_OBSERVER_POINTERS
 
template<class ObjectType> class TOPtr;
 
class CObservedMix
{
public:
 
    CObservedMix() : _ObserverId(ObserverId_Null) {}
    ~CObservedMix() { _ObserverId = ObserverId_Null; }
 
private:
 
    template<class ObjectType> friend class TOPtr;
 
    mutable EObserverId _ObserverId;
 
};
 
template<class ObjectType>
class TOPtr
{
public:
 
    // Construction
 
    ULANG_FORCEINLINE TOPtr() : _Object(nullptr), _ObserverId(ObserverId_Null) {}
    ULANG_FORCEINLINE TOPtr(const TOPtr & Other) : _Object(Other._Object), _ObserverId(Other._ObserverId) {}
    template<class OtherObjectType, typename = typename TEnableIf<TPointerIsConvertibleFromTo<OtherObjectType, ObjectType>::Value>::Type>
    ULANG_FORCEINLINE TOPtr(const TOPtr<OtherObjectType> & Other) : _Object(Other._Object), _ObserverId(Other._ObserverId) {}
    template<class OtherObjectType, bool OtherAllowNull, class AllocatorType, typename... AllocatorArgsType, typename = typename TEnableIf<TPointerIsConvertibleFromTo<OtherObjectType, ObjectType>::Value>::Type>
    ULANG_FORCEINLINE TOPtr(const TSPtrG<OtherObjectType, OtherAllowNull, AllocatorType, AllocatorArgsType...> & SharedPtr) : _Object(SharedPtr.Get()), _ObserverId(GetId(SharedPtr.Get(), SharedPtr.GetAllocator())) {}
    template<class OtherObjectType, bool OtherAllowNull, class AllocatorType, typename... AllocatorArgsType, typename = typename TEnableIf<TPointerIsConvertibleFromTo<OtherObjectType, ObjectType>::Value>::Type>
    ULANG_FORCEINLINE TOPtr(const TUPtrG<OtherObjectType, OtherAllowNull, AllocatorType, AllocatorArgsType...> & UniquePtr) : _Object(UniquePtr.Get()), _ObserverId(GetId(UniquePtr.Get(), UniquePtr.GetAllocator())) {}
 
    // Assignment
 
    ULANG_FORCEINLINE TOPtr & operator=(const TOPtr & Other) { _Object = Other._Object; _ObserverId = Other._ObserverId; return *this; }
    template<class OtherObjectType, typename = typename TEnableIf<TPointerIsConvertibleFromTo<OtherObjectType, ObjectType>::Value>::Type>
    ULANG_FORCEINLINE TOPtr & operator=(const TOPtr<OtherObjectType> & Other) { _Object = Other._Object; _ObserverId = Other._ObserverId; return *this; }
    template<class OtherObjectType, bool OtherAllowNull, class AllocatorType, typename... AllocatorArgsType, typename = typename TEnableIf<TPointerIsConvertibleFromTo<OtherObjectType, ObjectType>::Value>::Type>
    ULANG_FORCEINLINE TOPtr & operator=(const TSPtrG<OtherObjectType, OtherAllowNull, AllocatorType, AllocatorArgsType...> & SharedPtr) { _Object = SharedPtr.Get(); _ObserverId = GetId(SharedPtr.Get(), SharedPtr.GetAllocator()); return *this; }
    template<class OtherObjectType, bool OtherAllowNull, class AllocatorType, typename... AllocatorArgsType, typename = typename TEnableIf<TPointerIsConvertibleFromTo<OtherObjectType, ObjectType>::Value>::Type>
    ULANG_FORCEINLINE TOPtr & operator=(const TUPtrG<OtherObjectType, OtherAllowNull, AllocatorType, AllocatorArgsType...> & UniquePtr) { _Object = UniquePtr.Get(); _ObserverId = GetId(UniquePtr.Get(), UniquePtr.GetAllocator()); return *this; }
 
    // Conversion methods
 
    ULANG_FORCEINLINE operator ObjectType*() const { return Get(); }
    ULANG_FORCEINLINE ObjectType &       operator*() const { return *Get(); }
    ULANG_FORCEINLINE ObjectType *       operator->() const { return Get(); }
    ULANG_FORCEINLINE ObjectType *       Get() const { ULANG_ASSERTF(!_Object || _ObserverId == _Object->_ObserverId, "Observed object has been deleted!"); return _Object; }
    ULANG_FORCEINLINE void               Reset() { _Object = nullptr; _ObserverId = ObserverId_Null; }
 
    // Comparison operators
 
    ULANG_FORCEINLINE bool operator==(const TOPtr & Other) const { return (_Object == Other._Object); }
    ULANG_FORCEINLINE bool operator!=(const TOPtr & Other) const { return (_Object != Other._Object); }
    template<class OtherObjectType>
    ULANG_FORCEINLINE bool operator==(const TOPtr<OtherObjectType> & Other) const { return (_Object == Other._Object); }
    template<class OtherObjectType>
    ULANG_FORCEINLINE bool operator!=(const TOPtr<OtherObjectType> & Other) const { return (_Object != Other._Object); }
    template<class OtherObjectType>
    ULANG_FORCEINLINE bool operator==(OtherObjectType * Object) const { return (_Object == Object); }
    template<class OtherObjectType>
    ULANG_FORCEINLINE bool operator!=(OtherObjectType * Object) const { return (_Object != Object); }
 
    // Validation methods
 
    ULANG_FORCEINLINE bool IsValid() const { return (_Object && (_ObserverId == _Object->_ObserverId)); }
    ULANG_FORCEINLINE bool IsStale() const { return (_Object && (_ObserverId != _Object->_ObserverId)); }
    ULANG_FORCEINLINE bool IsNull() const { return !_Object; }
    ULANG_FORCEINLINE bool IsSet() const { return (_Object != nullptr); }
    ULANG_FORCEINLINE operator bool() const { return IsValid(); }
    ULANG_FORCEINLINE bool operator !() const { return IsNull(); }
 
    // Id Accessor
 
    ULANG_FORCEINLINE EObserverId GetObserverId() const { return _ObserverId; }
 
protected:
    template<class OtherObjectType> friend class TOPtr;
 
    template<class AllocatorType>
    ULANG_FORCEINLINE static EObserverId GetId(const ObjectType * Object, const AllocatorType & Allocator)
    {
        EObserverId ObserverId = Object->_ObserverId;
        if (ObserverId == ObserverId_Null)
        {
            Object->_ObserverId = ObserverId = Allocator.GenerateObserverId();
        }
        return ObserverId;
    }
 
    ObjectType * _Object;
 
    EObserverId _ObserverId;
 
};
 
#else // !ULANG_CHECK_OBSERVER_POINTERS
 
class CObservedMix
{
};
 
template<class ObjectType>
class TOPtr
{
public:
 
    // Construction
 
    ULANG_FORCEINLINE TOPtr() : _Object(nullptr) {}
    ULANG_FORCEINLINE TOPtr(const TOPtr & Other) : _Object(Other._Object) {}
    template<class OtherObjectType, typename = typename TEnableIf<TPointerIsConvertibleFromTo<OtherObjectType, ObjectType>::Value>::Type>
    ULANG_FORCEINLINE TOPtr(const TOPtr<OtherObjectType> & Other) : _Object(Other._Object) {}
    template<class OtherObjectType, bool OtherAllowNull, class AllocatorType, typename... AllocatorArgsType, typename = typename TEnableIf<TPointerIsConvertibleFromTo<OtherObjectType, ObjectType>::Value>::Type>
    ULANG_FORCEINLINE TOPtr(const TSPtrG<OtherObjectType, OtherAllowNull, AllocatorType, AllocatorArgsType...> & SharedPtr) : _Object(SharedPtr.Get()) {}
    template<class OtherObjectType, bool OtherAllowNull, class AllocatorType, typename... AllocatorArgsType, typename = typename TEnableIf<TPointerIsConvertibleFromTo<OtherObjectType, ObjectType>::Value>::Type>
    ULANG_FORCEINLINE TOPtr(const TUPtrG<OtherObjectType, OtherAllowNull, AllocatorType, AllocatorArgsType...> & UniquePtr) : _Object(UniquePtr.Get()) {}
 
    // Assignment
 
    ULANG_FORCEINLINE TOPtr & operator=(const TOPtr & Other) { _Object = Other._Object; return *this; }
    template<class OtherObjectType, typename = typename TEnableIf<TPointerIsConvertibleFromTo<OtherObjectType, ObjectType>::Value>::Type>
    ULANG_FORCEINLINE TOPtr & operator=(const TOPtr<OtherObjectType> & Other) { _Object = Other._Object; return *this; }
    template<class OtherObjectType, bool OtherAllowNull, class AllocatorType, typename... AllocatorArgsType, typename = typename TEnableIf<TPointerIsConvertibleFromTo<OtherObjectType, ObjectType>::Value>::Type>
    ULANG_FORCEINLINE TOPtr & operator=(const TSPtrG<OtherObjectType, OtherAllowNull, AllocatorType, AllocatorArgsType...> & SharedPtr) { _Object = SharedPtr.Get(); return *this; }
    template<class OtherObjectType, bool OtherAllowNull, class AllocatorType, typename... AllocatorArgsType, typename = typename TEnableIf<TPointerIsConvertibleFromTo<OtherObjectType, ObjectType>::Value>::Type>
    ULANG_FORCEINLINE TOPtr & operator=(const TUPtrG<OtherObjectType, OtherAllowNull, AllocatorType, AllocatorArgsType...> & UniquePtr) { _Object = UniquePtr.Get(); return *this; }
 
    // Conversion methods
 
    ULANG_FORCEINLINE operator ObjectType*() const { return _Object; }
    ULANG_FORCEINLINE ObjectType &       operator*() const { return *_Object; }
    ULANG_FORCEINLINE ObjectType *       operator->() const { return _Object; }
    ULANG_FORCEINLINE ObjectType *       Get() const { return _Object; }
    ULANG_FORCEINLINE void               Reset() { _Object = nullptr; }
 
    // Comparison operators
 
    ULANG_FORCEINLINE bool operator==(const TOPtr & Other) const { return (_Object == Other._Object); }
    ULANG_FORCEINLINE bool operator!=(const TOPtr & Other) const { return (_Object != Other._Object); }
    template<class OtherObjectType>
    ULANG_FORCEINLINE bool operator==(const TOPtr<OtherObjectType> & Other) const { return (_Object == Other._Object); }
    template<class OtherObjectType>
    ULANG_FORCEINLINE bool operator!=(const TOPtr<OtherObjectType> & Other) const { return (_Object != Other._Object); }
    ULANG_FORCEINLINE bool operator==(const ObjectType * Object) const { return (_Object == Object); }
    ULANG_FORCEINLINE bool operator!=(const ObjectType * Object) const { return (_Object != Object); }
 
    // Validation methods
 
    ULANG_FORCEINLINE bool IsValid() const { return _Object != nullptr; }
    ULANG_FORCEINLINE bool IsStale() const { return false; }
    ULANG_FORCEINLINE bool IsNull() const { return _Object == nullptr; }
    ULANG_FORCEINLINE bool IsSet() const { return _Object != nullptr; }
    ULANG_FORCEINLINE operator bool() const { return IsValid(); }
    ULANG_FORCEINLINE bool operator !() const { return IsNull(); }
 
protected:
    template<class OtherObjectType> friend class TOPtr;
 
    ObjectType * _Object;
 
};
 
 
#endif
 
}