FBufferOwner Class Reference

#include <SharedBuffer.h>

Inheritance diagram for FBufferOwner:

Public Types
enum class	EBufferOwnerFlags : uint8 { None = 0 , Owned = 1 << 0 , Immutable = 1 << 1 , Materialized = 1 << 2 }

Protected Member Functions
	FBufferOwner ()=default
	FBufferOwner (const FBufferOwner &)=delete
FBufferOwner &	operator= (const FBufferOwner &)=delete
	FBufferOwner (void *InData, uint64 InSize)
virtual	~FBufferOwner ()
virtual void	MaterializeBuffer ()
virtual void	FreeBuffer ()=0
void *	GetData ()
uint64	GetSize ()
void	SetBuffer (void *InData, uint64 InSize)
bool	IsOwned () const
void	SetIsOwned ()
bool	IsImmutable () const
void	SetIsImmutable ()
void	Materialize ()
bool	IsMaterialized () const
void	SetIsMaterialized ()
uint32	GetTotalRefCount () const

Friends
class	FUniqueBuffer
class	FSharedBuffer
class	FWeakSharedBuffer
struct	UE::SharedBuffer::Private::FSharedOps
struct	UE::SharedBuffer::Private::FWeakOps

Detailed Description

A reference-counted owner for a buffer, which is a raw pointer and size.

A buffer owner may own its memory or provide a view into memory owned externally. When used as a non-owning view, the viewed memory must be guaranteed to outlive the buffer owner. When this lifetime guarantee cannot be satisfied, MakeOwned may be called on the reference to the buffer to clone into a new buffer owner that owns the memory.

A buffer owner must be referenced and accessed through one of its three reference types: FUniqueBuffer, FSharedBuffer, or FWeakSharedBuffer.

FUniqueBuffer and FSharedBuffer offer static functions to create a buffer using private buffer owner types that are ideal for most use cases. The TakeOwnership function allows creation of a buffer with a custom delete function. Advanced use cases require deriving from FBufferOwner to enable storage of arbitrary members alongside the data and size, and to enable materialization of the buffer to be deferred.

A derived type must call SetIsOwned from its constructor if they own (or will own) the buffer. A derived type must call SetIsImmutable from its constructor if they want the buffer to become permanently immutable after it is stored in FSharedBuffer, forcing MoveToUnique() to clone it. A derived type must call SetIsMaterialized from its constructor, unless it implements deferred materialization by overriding MaterializeBuffer.

Member Enumeration Documentation

EBufferOwnerFlags

enum class FBufferOwner::EBufferOwnerFlags : uint8

strong

Enumerator
None
Owned
Immutable
Materialized

Constructor & Destructor Documentation

FBufferOwner() [1/3]

FBufferOwner::FBufferOwner ( )

protecteddefault

FBufferOwner() [2/3]

FBufferOwner::FBufferOwner ( const FBufferOwner &  )

protecteddelete

FBufferOwner() [3/3]

FBufferOwner::FBufferOwner ( void *  InData, uint64  InSize  )

inlineprotected

~FBufferOwner()

FBufferOwner::~FBufferOwner ( )

inlineprotectedvirtual

Member Function Documentation

FreeBuffer()

virtual void FBufferOwner::FreeBuffer ( )

protectedpure virtual

Free the buffer and any associated resources.

This is called when the last shared reference is released. The destructor will be called when the last weak reference is released. A buffer owner will always call this function before the calling the destructor, unless an exception was thrown by the constructor.

Implemented in UE::SharedBuffer::Private::FBufferOwnerHeap, UE::SharedBuffer::Private::FBufferOwnerView, and UE::SharedBuffer::Private::FBufferOwnerOuterView.

GetData()

void * FBufferOwner::GetData ( )

inlineprotected

GetSize()

uint64 FBufferOwner::GetSize ( )

inlineprotected

GetTotalRefCount()

uint32 FBufferOwner::GetTotalRefCount ( ) const

inlineprotected

IsImmutable()

bool FBufferOwner::IsImmutable ( ) const

inlineprotected

IsMaterialized()

bool FBufferOwner::IsMaterialized ( ) const

inlineprotected

IsOwned()

bool FBufferOwner::IsOwned ( ) const

inlineprotected

Materialize()

void FBufferOwner::Materialize ( )

inlineprotected

MaterializeBuffer()

void FBufferOwner::MaterializeBuffer ( )

inlineprotectedvirtual

Materialize the buffer by making it ready to be accessed.

This will be called before any access to the data or size, unless SetIsMaterialized is called by the constructor. Accesses from multiple threads will cause multiple calls to this function until at least one has finished.

operator=()

FBufferOwner & FBufferOwner::operator= ( const FBufferOwner &  )

protecteddelete

SetBuffer()

void FBufferOwner::SetBuffer ( void *  InData, uint64  InSize  )

inlineprotected

SetIsImmutable()

void FBufferOwner::SetIsImmutable ( )

inlineprotected

SetIsMaterialized()

void FBufferOwner::SetIsMaterialized ( )

inlineprotected

SetIsOwned()

void FBufferOwner::SetIsOwned ( )

inlineprotected

Friends And Related Symbol Documentation

FSharedBuffer

friend class FSharedBuffer

friend

FUniqueBuffer

friend class FUniqueBuffer

friend

FWeakSharedBuffer

friend class FWeakSharedBuffer

friend

UE::SharedBuffer::Private::FSharedOps

friend struct UE::SharedBuffer::Private::FSharedOps

friend

UE::SharedBuffer::Private::FWeakOps

friend struct UE::SharedBuffer::Private::FWeakOps

friend

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The documentation for this class was generated from the following file:

• Engine/Source/Runtime/Core/Public/Memory/SharedBuffer.h