// Copyright Epic Games, Inc. All Rights Reserved.

/*=============================================================================
        UObjectBase.h: Base class for UObject, defines low level functionality
=============================================================================*/

#pragma once

#include "CoreMinimal.h"
#include "Stats/Stats.h"
#include "UObject/ObjectMacros.h"
#include "UObject/UObjectGlobals.h"
#include "HAL/LowLevelMemTracker.h"

DECLARE_DWORD_COUNTER_STAT_EXTERN(TEXT("STAT_UObjectsStatGroupTester"), STAT_UObjectsStatGroupTester, STATGROUP_UObjects, COREUOBJECT_API);

/**
 * Low level implementation of UObject, should not be used directly in game code
 */
class COREUOBJECT_API UObjectBase
{
    friend class UObjectBaseUtility;
    friend struct Z_Construct_UClass_UObject_Statics;
    friend class FUObjectArray;      // for access to InternalIndex without revealing it to anyone else
    friend class FUObjectAllocator;  // for access to destructor without revealing it to anyone else
    friend COREUOBJECT_API void UObjectForceRegistration(UObjectBase* Object, bool bCheckForModuleRelease);
    friend COREUOBJECT_API void InitializePrivateStaticClass(
        class UClass* TClass_Super_StaticClass,
        class UClass* TClass_PrivateStaticClass,
        class UClass* TClass_WithinClass_StaticClass,
        const TCHAR* PackageName,
        const TCHAR* Name);

protected:
    UObjectBase(): NamePrivate(NoInit)  // screwy, but the name was already set and we don't want to set it again
    {
    }

    /**
     * Constructor used for bootstrapping
     * @param	InFlags			RF_Flags to assign
     */
    UObjectBase(EObjectFlags InFlags);

public:
    /**
     * Constructor used by StaticAllocateObject
     * @param	InClass				non NULL, this gives the class of the new object, if known at this time
     * @param	InFlags				RF_Flags to assign
     * @param	InInternalFlags EInternalObjectFlags to assign
     * @param	InOuter				outer for this object
     * @param	InName				name of the new object
     */
    UObjectBase(UClass* InClass, EObjectFlags InFlags, EInternalObjectFlags InInternalFlags, UObject* InOuter, FName InName);

    /**
     * Final destructor, removes the object from the object array, and indirectly, from any annotations
     **/
    virtual ~UObjectBase();

    /**
     * Emit GC tokens for UObjectBase, this might be UObject::StaticClass or Default__Class
     **/
    static void EmitBaseReferences(UClass* RootClass);

protected:
    /**
     * Just change the FName and Outer and rehash into name hash tables. For use by higher level rename functions.
     *
     * @param NewName	new name for this object
     * @param NewOuter	new outer for this object, if NULL, outer will be unchanged
     */
    void LowLevelRename(FName NewName, UObject* NewOuter = NULL);

    /** Force any base classes to be registered first */
    virtual void RegisterDependencies() {}

    /** Enqueue the registration for this object. */
    void Register(const TCHAR* PackageName, const TCHAR* Name);

    /**
     * Convert a boot-strap registered class into a real one, add to uobject array, etc
     *
     * @param UClassStaticClass Now that it is known, fill in UClass::StaticClass() as the class
     */
    virtual void DeferredRegister(UClass* UClassStaticClass, const TCHAR* PackageName, const TCHAR* Name);

private:
    /**
     * Add a newly created object to the name hash tables and the object array
     *
     * @param Name name to assign to this uobject
     * @param InSetInternalFlags Internal object flags to be set on the object once it's been added to the array
     */
    void AddObject(FName Name, EInternalObjectFlags InSetInternalFlags);

public:
    /**
     * Checks to see if the object appears to be valid
     * @return true if this appears to be a valid object
     */
    bool IsValidLowLevel() const;

    /**
     * Faster version of IsValidLowLevel.
     * Checks to see if the object appears to be valid by checking pointers and their alignment.
     * Name and InternalIndex checks are less accurate than IsValidLowLevel.
     * @param bRecursive true if the Class pointer should be checked with IsValidLowLevelFast
     * @return true if this appears to be a valid object
     */
    bool IsValidLowLevelFast(bool bRecursive = true) const;

    /**
     * Returns the unique ID of the object...these are reused so it is only unique while the object is alive.
     * Useful as a tag.
     **/
    FORCEINLINE uint32 GetUniqueID() const
    {
        return (uint32)InternalIndex;
    }

    /** Returns the UClass that defines the fields of this object */
    FORCEINLINE UClass* GetClass() const
    {
        return ClassPrivate;
    }

    /** Returns the UObject this object resides in */
    FORCEINLINE UObject* GetOuter() const
    {
        return OuterPrivate;
    }

    /** Returns the logical name of this object */
    FORCEINLINE FName GetFName() const
    {
        return NamePrivate;
    }

    /** Removes the class prefix from the given string */
    static FString RemoveClassPrefix(const TCHAR* ClassName);

    /** Returns the external UPackage associated with this object, if any */
    UPackage* GetExternalPackage() const;

    /** Associate an external package directly to this object. */
    void SetExternalPackage(UPackage* InPackage);

    /** Returns the external UPackage for this object, if any, NOT THREAD SAFE, used by internal gc reference collecting. */
    UPackage* GetExternalPackageInternal() const;

protected:
    /**
     * Set the object flags directly
     *
     **/
    FORCEINLINE void SetFlagsTo(EObjectFlags NewFlags)
    {
        checkfSlow((NewFlags & ~RF_AllFlags) == 0, TEXT("%s flagged as 0x%x but is trying to set flags to RF_AllFlags"), *GetFName().ToString(), (int)ObjectFlags);
        ObjectFlags = NewFlags;
    }

public:
    /**
     * Retrieve the object flags directly
     *
     * @return Flags for this object
     **/
    FORCEINLINE EObjectFlags GetFlags() const
    {
        checkfSlow((ObjectFlags & ~RF_AllFlags) == 0, TEXT("%s flagged as RF_AllFlags"), *GetFName().ToString());
        return ObjectFlags;
    }

    /**
     *	Atomically adds the specified flags.
     *	Do not use unless you know what you are doing.
     *	Designed to be used only by parallel GC and UObject loading thread.
     */
    FORCENOINLINE void AtomicallySetFlags(EObjectFlags FlagsToAdd)
    {
        int32 OldFlags = 0;
        int32 NewFlags = 0;
        do
        {
            OldFlags = ObjectFlags;
            NewFlags = OldFlags | FlagsToAdd;
        } while (FPlatformAtomics::InterlockedCompareExchange((int32*)&ObjectFlags, NewFlags, OldFlags) != OldFlags);
    }

    /**
     *	Atomically clears the specified flags.
     *	Do not use unless you know what you are doing.
     *	Designed to be used only by parallel GC and UObject loading thread.
     */
    FORCENOINLINE void AtomicallyClearFlags(EObjectFlags FlagsToClear)
    {
        int32 OldFlags = 0;
        int32 NewFlags = 0;
        do
        {
            OldFlags = ObjectFlags;
            NewFlags = OldFlags & ~FlagsToClear;
        } while (FPlatformAtomics::InterlockedCompareExchange((int32*)&ObjectFlags, NewFlags, OldFlags) != OldFlags);
    }

private:
    /** Flags used to track and report various object states. This needs to be 8 byte aligned on 32-bit
        platforms to reduce memory waste */
    EObjectFlags ObjectFlags;

    /** Index into GObjectArray...very private. */
    int32 InternalIndex;

    /** Class the object belongs to. */
    UClass* ClassPrivate;

    /** Name of this object */
    FName NamePrivate;

    /** Object this object resides in. */
    UObject* OuterPrivate;

    friend class FBlueprintCompileReinstancer;
    friend class FContextObjectManager;

    /** This is used by the reinstancer to re-class and re-archetype the current instances of a class before recompiling */
    void SetClass(UClass* NewClass);

#if HACK_HEADER_GENERATOR
    // Required by UHT makefiles for internal data serialization.
    friend struct FObjectBaseArchiveProxy;
#endif  // HACK_HEADER_GENERATOR
};

/**
 * Checks to see if the UObject subsystem is fully bootstrapped and ready to go.
 * If true, then all objects are registered and auto registration of natives is over, forever.
 *
 * @return true if the UObject subsystem is initialized.
 */
COREUOBJECT_API bool UObjectInitialized();

/**
 * Force a pending registrant to register now instead of in the natural order
 */
COREUOBJECT_API void UObjectForceRegistration(UObjectBase* Object, bool bCheckForModuleRelease = true);

/**
 * Base class for deferred native class registration
 */
struct FFieldCompiledInInfo
{
    FFieldCompiledInInfo(SIZE_T InClassSize, uint32 InCrc)
        : Size(InClassSize), Crc(InCrc), OldClass(nullptr), bHasChanged(false)
    {
    }

    /** Registers the native class (constructs a UClass object) */
    virtual UClass* Register() const = 0;

    /** Return the package the class belongs in */
    virtual const TCHAR* ClassPackage() const = 0;

    /** Size of the class */
    SIZE_T Size;
    /** CRC of the generated code for this class */
    uint32 Crc;
    /** Old UClass object */
    UClass* OldClass;
    /** True if this class has changed after hot-reload (or new class) */
    bool bHasChanged;
};

/**
 * Adds a class to deferred registration queue.
 */
COREUOBJECT_API void UClassCompiledInDefer(FFieldCompiledInInfo* Class, const TCHAR* Name, SIZE_T ClassSize, uint32 Crc);

/**
 * Specialized version of the deferred class registration structure.
 */
template <typename TClass>
struct TClassCompiledInDefer: public FFieldCompiledInInfo
{
    TClassCompiledInDefer(const TCHAR* InName, SIZE_T InClassSize, uint32 InCrc)
        : FFieldCompiledInInfo(InClassSize, InCrc)
    {
        UClassCompiledInDefer(this, InName, InClassSize, InCrc);
    }
    virtual UClass* Register() const override
    {
        LLM_SCOPE(ELLMTag::UObject);
        return TClass::StaticClass();
    }
    virtual const TCHAR* ClassPackage() const override
    {
        return TClass::StaticPackage();
    }
};

/**
 * Stashes the singleton function that builds a compiled in class. Later, this is executed.
 */
COREUOBJECT_API void UObjectCompiledInDefer(class UClass* (*InRegister)(), class UClass* (*InStaticClass)(), const TCHAR* Name, const TCHAR* PackageName, bool bDynamic, const TCHAR* DynamicPathName, void (*InInitSearchableValues)(TMap<FName, FName>&));

struct FCompiledInDefer
{
    FCompiledInDefer(class UClass* (*InRegister)(), class UClass* (*InStaticClass)(), const TCHAR* PackageName, const TCHAR* Name, bool bDynamic, const TCHAR* DynamicPackageName = nullptr, const TCHAR* DynamicPathName = nullptr, void (*InInitSearchableValues)(TMap<FName, FName>&) = nullptr)
    {
        if (bDynamic)
        {
            GetConvertedDynamicPackageNameToTypeName().Add(FName(DynamicPackageName), FName(Name));
        }
        UObjectCompiledInDefer(InRegister, InStaticClass, Name, PackageName, bDynamic, DynamicPathName, InInitSearchableValues);
    }
};

/**
 * Stashes the singleton function that builds a compiled in struct (StaticStruct). Later, this is executed.
 */
COREUOBJECT_API void UObjectCompiledInDeferStruct(class UScriptStruct* (*InRegister)(), const TCHAR* PackageName, const TCHAR* ObjectName, bool bDynamic, const TCHAR* DynamicPathName);

struct FCompiledInDeferStruct
{
    FCompiledInDeferStruct(class UScriptStruct* (*InRegister)(), const TCHAR* PackageName, const TCHAR* Name, bool bDynamic, const TCHAR* DynamicPackageName, const TCHAR* DynamicPathName)
    {
        if (bDynamic)
        {
            GetConvertedDynamicPackageNameToTypeName().Add(FName(DynamicPackageName), FName(Name));
        }
        UObjectCompiledInDeferStruct(InRegister, PackageName, Name, bDynamic, DynamicPathName);
    }
};

/**
 * Either call the passed in singleton, or if this is hot reload, find the existing struct
 */
COREUOBJECT_API class UScriptStruct* GetStaticStruct(class UScriptStruct* (*InRegister)(), UObject* StructOuter, const TCHAR* StructName, SIZE_T Size, uint32 Crc);

/**
 * Stashes the singleton function that builds a compiled in enum. Later, this is executed.
 */
COREUOBJECT_API void UObjectCompiledInDeferEnum(class UEnum* (*InRegister)(), const TCHAR* PackageName, const TCHAR* ObjectName, bool bDynamic, const TCHAR* DynamicPathName);

struct FCompiledInDeferEnum
{
    FCompiledInDeferEnum(class UEnum* (*InRegister)(), const TCHAR* PackageName, const TCHAR* Name, bool bDynamic, const TCHAR* DynamicPackageName, const TCHAR* DynamicPathName)
    {
        if (bDynamic)
        {
            GetConvertedDynamicPackageNameToTypeName().Add(FName(DynamicPackageName), FName(Name));
        }
        UObjectCompiledInDeferEnum(InRegister, PackageName, Name, bDynamic, DynamicPathName);
    }
};

/**
 * Either call the passed in singleton, or if this is hot reload, find the existing enum
 */
COREUOBJECT_API class UEnum* GetStaticEnum(class UEnum* (*InRegister)(), UObject* EnumOuter, const TCHAR* EnumName);

/** Called during HotReload to hook up an existing structure */
COREUOBJECT_API class UScriptStruct* FindExistingStructIfHotReloadOrDynamic(UObject* Outer, const TCHAR* StructName, SIZE_T Size, uint32 Crc, bool bIsDynamic);

/** Called during HotReload to hook up an existing enum */
COREUOBJECT_API class UEnum* FindExistingEnumIfHotReloadOrDynamic(UObject* Outer, const TCHAR* EnumName, SIZE_T Size, uint32 Crc, bool bIsDynamic);

/** Must be called after a module has been loaded that contains UObject classes */
COREUOBJECT_API void ProcessNewlyLoadedUObjects(FName Package = NAME_None, bool bCanProcessNewlyLoadedObjects = true);

#if WITH_HOT_RELOAD
/** Map of duplicated CDOs for reinstancing during hot-reload purposes. */
COREUOBJECT_API TMap<UObject*, UObject*>& GetDuplicatedCDOMap();
#endif  // WITH_HOT_RELOAD

/**
 * Final phase of UObject initialization. all auto register objects are added to the main data structures.
 */
void UObjectBaseInit();

/**
 * Final phase of UObject shutdown
 */
void UObjectBaseShutdown();