UProperty(含其子类)实例描述了类的某个成员变量的反射信息。
- UProperty类
//
// An UnrealScript variable.
// Property的名字在基类中
//
class COREUOBJECT_API UProperty : public UField
{
DECLARE_CASTED_CLASS_INTRINSIC_NO_CTOR(UProperty, UField, CLASS_Abstract, TEXT("/Script/CoreUObject"), CASTCLASS_UProperty, NO_API)
DECLARE_WITHIN(UField) // 该对象实例只能在UField类对象中(Outer关系约束)。
// Persistent variables.
int32 ArrayDim; // Property维度, 例如: int a, 维度1; int a[20], 维度20.
int32 ElementSize; // 数组元素大小
uint64 PropertyFlags; // 标记
uint16 RepIndex; // Replication时使用
FName RepNotifyFunc; // 在network replication时，变量发生变化的通知回调函数名称。
private:
// In memory variables (generated during Link()).
int32 Offset_Internal; // 类的成员变量在类内存布局中的偏移量
ELifetimeCondition BlueprintReplicationCondition;
public:
/** In memory only: Linked list of properties from most-derived to base **/
UProperty* PropertyLinkNext;
/** In memory only: Linked list of object reference properties from most-derived to base **/
UProperty* NextRef;
/** In memory only: Linked list of properties requiring destruction. Note this does not include things that will be destroyed byt he native destructor **/
UProperty* DestructorLinkNext;
/** In memory only: Linked list of properties requiring post constructor initialization.**/
UProperty* PostConstructLinkNext;
- UBoolProperty
//
// Describes a single bit flag variable residing in a 32-bit unsigned double word.
//
class COREUOBJECT_API UBoolProperty : public UProperty
{
DECLARE_CASTED_CLASS_INTRINSIC_NO_CTOR(UBoolProperty, UProperty, 0, TEXT("/Script/CoreUObject"), CASTCLASS_UBoolProperty, NO_API)
// Variables.
private:
/** Size of the bitfield/bool property. Equal to ElementSize but used to check if the property has been properly initialized (0-8, where 0 means uninitialized). */
uint8 FieldSize;
/** Offset from the memeber variable to the byte of the property (0-7). */
uint8 ByteOffset;
/** Mask of the byte byte with the property value. */
uint8 ByteMask;
/** Mask of the field with the property value. Either equal to ByteMask or 255 in case of 'bool' type. */
uint8 FieldMask;
public:
+UEnumProperty
class COREUOBJECT_API UEnumProperty : public UProperty
{
DECLARE_CASTED_CLASS_INTRINSIC(UEnumProperty, UProperty, 0, TEXT("/Script/CoreUObject"), CASTCLASS_UEnumProperty)
public:
UEnumProperty(const FObjectInitializer& ObjectInitializer, UEnum* InEnum);
UEnumProperty(const FObjectInitializer& ObjectInitializer, ECppProperty, int32 InOffset, uint64 InFlags, UEnum* InEnum);
// UObject interface
virtual void Serialize( FArchive& Ar ) override;
static void AddReferencedObjects(UObject* InThis, FReferenceCollector& Collector);
virtual void GetPreloadDependencies(TArray<UObject*>& OutDeps) override;
// End of UObject interface
// UField interface
virtual void AddCppProperty(UProperty* Property) override;
// End of UField interface
// UProperty interface
virtual FString GetCPPMacroType( FString& ExtendedTypeText ) const override;
virtual FString GetCPPType( FString* ExtendedTypeText, uint32 CPPExportFlags ) const override;
virtual FString GetCPPTypeForwardDeclaration() const override;
virtual void LinkInternal(FArchive& Ar) override;
virtual bool Identical( const void* A, const void* B, uint32 PortFlags ) const override;
virtual void SerializeItem( FArchive& Ar, void* Value, void const* Defaults ) const override;
virtual bool NetSerializeItem( FArchive& Ar, UPackageMap* Map, void* Data, TArray<uint8> * MetaData = NULL ) const override;
virtual void ExportTextItem( FString& ValueStr, const void* PropertyValue, const void* DefaultValue, UObject* Parent, int32 PortFlags, UObject* ExportRootScope ) const override;
virtual const TCHAR* ImportText_Internal( const TCHAR* Buffer, void* Data, int32 PortFlags, UObject* OwnerObject, FOutputDevice* ErrorText ) const override;
virtual int32 GetMinAlignment() const override;
virtual bool SameType(const UProperty* Other) const override;
virtual bool ConvertFromType(const FPropertyTag& Tag, FArchive& Ar, uint8* Data, UStruct* DefaultsStruct, bool& bOutAdvanceProperty) override;
// End of UProperty interface
/**
* Returns a pointer to the UEnum of this property.
*/
FORCEINLINE UEnum* GetEnum() const
{
return Enum;
}
/**
* Returns the numeric property which represents the integral type of the enum.
*/
FORCEINLINE UNumericProperty* GetUnderlyingProperty() const
{
return UnderlyingProp;
}
private:
virtual uint32 GetValueTypeHashInternal(const void* Src) const override;
friend struct UE4EnumProperty_Private::FEnumPropertyFriend;
#if HACK_HEADER_GENERATOR
public:
#endif
UNumericProperty* UnderlyingProp; // The property which represents the underlying type of the enum
UEnum* Enum; // The enum represented by this property 所属的Enum类型
};
- UNumericProperty
数字属性类, 其子类有 int32, int64, uint32, uint64, float, double等其它具体类型数字的属性类。
class COREUOBJECT_API UNumericProperty : public UProperty
{
DECLARE_CASTED_CLASS_INTRINSIC(UNumericProperty, UProperty, CLASS_Abstract, TEXT("/Script/CoreUObject"), CASTCLASS_UNumericProperty)
UNumericProperty(ECppProperty, int32 InOffset, uint64 InFlags)
: UProperty(FObjectInitializer::Get(), EC_CppProperty, InOffset, InFlags)
{}
UNumericProperty( const FObjectInitializer& ObjectInitializer, ECppProperty, int32 InOffset, uint64 InFlags )
: UProperty( ObjectInitializer, EC_CppProperty, InOffset, InFlags )
{}
// UProperty interface.
virtual const TCHAR* ImportText_Internal( const TCHAR* Buffer, void* Data, int32 PortFlags, UObject* Parent, FOutputDevice* ErrorText ) const override;
virtual void ExportTextItem( FString& ValueStr, const void* PropertyValue, const void* DefaultValue, UObject* Parent, int32 PortFlags, UObject* ExportRootScope ) const override;
// End of UProperty interface
// UNumericProperty interface.
/** Return true if this property is for a floating point number **/
virtual bool IsFloatingPoint() const;
/** Return true if this property is for a integral or enum type **/
virtual bool IsInteger() const;
};
- UObjectProperty
对象引用属性类。
//
// Describes a reference variable to another object which may be nil.
//
class COREUOBJECT_API UObjectProperty : public TUObjectPropertyBase<UObject*>
{
DECLARE_CASTED_CLASS_INTRINSIC(UObjectProperty, TUObjectPropertyBase<UObject*>, 0, TEXT("/Script/CoreUObject"), CASTCLASS_UObjectProperty)
UObjectProperty(ECppProperty, int32 InOffset, uint64 InFlags, UClass* InClass)
: TUObjectPropertyBase(FObjectInitializer::Get(), EC_CppProperty, InOffset, InFlags, InClass)
{
}
UObjectProperty( const FObjectInitializer& ObjectInitializer, ECppProperty, int32 InOffset, uint64 InFlags, UClass* InClass )
: TUObjectPropertyBase(ObjectInitializer, EC_CppProperty, InOffset, InFlags, InClass)
{
}
// UHT interface
virtual FString GetCPPMacroType( FString& ExtendedTypeText ) const override;
virtual FString GetCPPTypeForwardDeclaration() const override;
// End of UHT interface
// UProperty interface
virtual void SerializeItem( FArchive& Ar, void* Value, void const* Defaults ) const override;
virtual void EmitReferenceInfo(UClass& OwnerClass, int32 BaseOffset, TArray<const UStructProperty*>& EncounteredStructProps) override;
virtual const TCHAR* ImportText_Internal(const TCHAR* Buffer, void* Data, int32 PortFlags, UObject* OwnerObject, FOutputDevice* ErrorText) const override;
virtual bool ConvertFromType(const FPropertyTag& Tag, FArchive& Ar, uint8* Data, UStruct* DefaultsStruct, bool& bOutAdvanceProperty) override;
private:
virtual uint32 GetValueTypeHashInternal(const void* Src) const override;
public:
// End of UProperty interface
// UObjectPropertyBase interface
virtual UObject* GetObjectPropertyValue(const void* PropertyValueAddress) const override;
virtual void SetObjectPropertyValue(void* PropertyValueAddress, UObject* Value) const override;
virtual FString GetCPPTypeCustom(FString* ExtendedTypeText, uint32 CPPExportFlags, const FString& InnerNativeTypeName) const override;
// End of UObjectPropertyBase interface
};
- UArrayProperty
动态数组成员变量属性, 对应C++中TArray<XXX>
//
// Describes a dynamic array.
//
// need to break this out a different type so that the DECLARE_CASTED_CLASS_INTRINSIC macro can digest the comma
typedef TProperty<FScriptArray, UProperty> UArrayProperty_Super;
class COREUOBJECT_API UArrayProperty : public UArrayProperty_Super
{
DECLARE_CASTED_CLASS_INTRINSIC(UArrayProperty, UArrayProperty_Super, 0, TEXT("/Script/CoreUObject"), CASTCLASS_UArrayProperty)
// Variables.
UProperty* Inner; // 描述数组元素的类型
public:
typedef UArrayProperty_Super::TTypeFundamentals TTypeFundamentals;
typedef TTypeFundamentals::TCppType TCppType;
UArrayProperty(ECppProperty, int32 InOffset, uint64 InFlags)
: UArrayProperty_Super(FObjectInitializer::Get(), EC_CppProperty, InOffset, InFlags)
{
}
UArrayProperty( const FObjectInitializer& ObjectInitializer, ECppProperty, int32 InOffset, uint64 InFlags )
: UArrayProperty_Super( ObjectInitializer, EC_CppProperty, InOffset, InFlags)
{
}
// UObject interface
virtual void Serialize( FArchive& Ar ) override;
static void AddReferencedObjects(UObject* InThis, FReferenceCollector& Collector);
virtual void GetPreloadDependencies(TArray<UObject*>& OutDeps) override;
// End of UObject interface
// UField interface
virtual void AddCppProperty( UProperty* Property ) override;
// End of UField interface
// UProperty interface
virtual FString GetCPPMacroType( FString& ExtendedTypeText ) const override;
virtual FString GetCPPType( FString* ExtendedTypeText, uint32 CPPExportFlags ) const override;
virtual FString GetCPPTypeForwardDeclaration() const override;
virtual void LinkInternal(FArchive& Ar) override;
virtual bool Identical( const void* A, const void* B, uint32 PortFlags ) const override;
virtual void SerializeItem( FArchive& Ar, void* Value, void const* Defaults ) const override;
virtual bool NetSerializeItem( FArchive& Ar, UPackageMap* Map, void* Data, TArray<uint8> * MetaData = NULL ) const override;
virtual void ExportTextItem( FString& ValueStr, const void* PropertyValue, const void* DefaultValue, UObject* Parent, int32 PortFlags, UObject* ExportRootScope ) const override;
virtual const TCHAR* ImportText_Internal( const TCHAR* Buffer, void* Data, int32 PortFlags, UObject* OwnerObject, FOutputDevice* ErrorText ) const override;
virtual void CopyValuesInternal( void* Dest, void const* Src, int32 Count ) const override;
virtual void ClearValueInternal( void* Data ) const override;
virtual void DestroyValueInternal( void* Dest ) const override;
virtual bool PassCPPArgsByRef() const override;
virtual void InstanceSubobjects( void* Data, void const* DefaultData, UObject* Owner, struct FObjectInstancingGraph* InstanceGraph ) override;
virtual bool ContainsObjectReference(TArray<const UStructProperty*>& EncounteredStructProps) const override;
virtual bool ContainsWeakObjectReference() const override;
virtual void EmitReferenceInfo(UClass& OwnerClass, int32 BaseOffset, TArray<const UStructProperty*>& EncounteredStructProps) override;
virtual bool SameType(const UProperty* Other) const override;
virtual bool ConvertFromType(const FPropertyTag& Tag, FArchive& Ar, uint8* Data, UStruct* DefaultsStruct, bool& bOutAdvanceProperty) override;
// End of UProperty interface
FString GetCPPTypeCustom(FString* ExtendedTypeText, uint32 CPPExportFlags, const FString& InnerTypeText, const FString& InInnerExtendedTypeText) const;
};
- UStructProperty
描述结构体成员变量的属性。
//
// Describes a structure variable embedded in (as opposed to referenced by)
// an object.
//
class COREUOBJECT_API UStructProperty : public UProperty
{
DECLARE_CASTED_CLASS_INTRINSIC(UStructProperty, UProperty, 0, TEXT("/Script/CoreUObject"), CASTCLASS_UStructProperty)
// Variables.
class UScriptStruct* Struct; // 该结构体类型的反射数据（元数据）
public:
UStructProperty(ECppProperty, int32 InOffset, uint64 InFlags, UScriptStruct* InStruct);
UStructProperty( const FObjectInitializer& ObjectInitializer, ECppProperty, int32 InOffset, uint64 InFlags, UScriptStruct* InStruct );
// UObject interface
virtual void Serialize( FArchive& Ar ) override;
static void AddReferencedObjects(UObject* InThis, FReferenceCollector& Collector);
virtual void GetPreloadDependencies(TArray<UObject*>& OutDeps) override;
// End of UObject interface
};
还有其它Property类，用于描述C++或蓝图的数据类型, TMap, TSet，Delegate等等。阅读源码的时候需要弄清各个字段的含义。
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