#include <DataReplication.h>

Classes
struct	FRPCCallInfo

struct	FRPCPendingLocalCall

Public Types
enum class	ESkipRpcBehavior { NeverSkip , SkipIfNotReady , AlwaysSkip }

Public Member Functions
ENGINE_API	FObjectReplicator ()

ENGINE_API	~FObjectReplicator ()

ENGINE_API void	InitWithObject (UObject InObject, UNetConnection InConnection, bool bUseDefaultState=true)

ENGINE_API void	CleanUp ()

ENGINE_API void	StartReplicating (class UActorChannel *InActorChannel)

ENGINE_API void	StopReplicating (class UActorChannel *InActorChannel)

ENGINE_API void	InitRecentProperties (uint8 *Source)

ENGINE_API bool	ValidateAgainstState (const UObject *ObjectState)

ENGINE_API bool	SendCustomDeltaProperty (UObject *InObject, uint16 CustomDeltaProperty, FNetBitWriter &OutBunch, TSharedPtr< INetDeltaBaseState > &NewFullState, TSharedPtr< INetDeltaBaseState > &OldState)

ENGINE_API void	ReceivedNak (int32 NakPacketId)

ENGINE_API void	CountBytes (FArchive &Ar) const

ENGINE_API void	ReplicateCustomDeltaProperties (FNetBitWriter &Bunch, FReplicationFlags RepFlags, bool &bSkippedPropertyCondition)

ENGINE_API bool	ReplicateProperties (FOutBunch &Bunch, FReplicationFlags RepFlags)

ENGINE_API bool	ReplicateProperties (FOutBunch &Bunch, FReplicationFlags RepFlags, FNetBitWriter &Writer)

ENGINE_API bool	ReplicateProperties_r (FOutBunch &Bunch, FReplicationFlags RepFlags, FNetBitWriter &Writer)

ENGINE_API void	PostSendBunch (FPacketIdRange &PacketRange, uint8 bReliable)

ENGINE_API bool	ReceivedBunch (FNetBitReader &Bunch, const FReplicationFlags &RepFlags, const bool bHasRepLayout, bool &bOutHasUnmapped)

ENGINE_API bool	ReceivedRPC (FNetBitReader &Reader, TSet< FNetworkGUID > &OutUnmappedGuids, bool &bOutSkippedRpcExec, const FReplicationFlags &RepFlags, const FFieldNetCache *FieldCache, ESkipRpcBehavior SkipRpcBehavior)

bool	ReceivedRPC (FNetBitReader &Reader, const FReplicationFlags &RepFlags, const FFieldNetCache *FieldCache, const bool bCanDelayRPC, bool &bOutDelayRPC, TSet< FNetworkGUID > &OutUnmappedGuids)

ENGINE_API void	UpdateGuidToReplicatorMap ()

ENGINE_API bool	MoveMappedObjectToUnmapped (const FNetworkGUID &GUID)

ENGINE_API void	PostReceivedBunch ()

ENGINE_API void	ForceRefreshUnreliableProperties ()

ENGINE_API void	QueueRemoteFunctionBunch (UFunction *Func, FOutBunch &Bunch)

ENGINE_API bool	ReadyForDormancy (bool bDebug=false)

ENGINE_API void	StartBecomingDormant ()

ENGINE_API void	CallRepNotifies (bool bSkipIfChannelHasQueuedBunches) const

ENGINE_API void	UpdateUnmappedObjects (bool &bOutHasMoreUnmapped)

ENGINE_API void	ExecutePendingTransactionalRPCs ()

TWeakObjectPtr< UObject >	GetWeakObjectPtr () const

UObject *	GetObject () const

void	SetObject (UObject *NewObj)

void	ReleaseStrongReference ()

void	PreNetReceive ()

void	PostNetReceive ()

ENGINE_API void	QueuePropertyRepNotify (UObject Object, FProperty Property, const int32 ElementIndex, TArray< uint8 > &MetaData)

ENGINE_API void	WritePropertyHeaderAndPayload (UObject Object, FProperty Property, FNetFieldExportGroup *NetFieldExportGroup, FNetBitWriter &Bunch, FNetBitWriter &Payload) const

ENGINE_API bool	CanSkipUpdate (FReplicationFlags Flags)

bool	IsDirtyForReplay () const

void	ResetReplayDirtyTracking ()

Public Attributes
FNetworkGUID	ObjectNetGUID

int32	TrackedGuidMemoryBytes

uint32	bLastUpdateEmpty: 1

uint32	bOpenAckCalled: 1

uint32	bForceUpdateUnmapped: 1

uint32	bHasReplicatedProperties: 1

uint32	bSentSubObjectCreation: 1

TSharedPtr< class FReplicationChangelistMgr >	ChangelistMgr

TSharedPtr< FRepLayout >	RepLayout

TUniquePtr< FRepState >	RepState

TUniquePtr< FRepState >	CheckpointRepState

TObjectPtr< UClass >	ObjectClass

UObject *	ObjectPtr

UNetConnection *	Connection

class UActorChannel *	OwningChannel

FOutBunch *	RemoteFunctions

TArray< FRPCCallInfo >	RemoteFuncInfo

TArray< FRPCPendingLocalCall >	PendingLocalRPCs

TSet< FNetworkGUID >	ReferencedGuids

Detailed Description

Represents an object that is currently being replicated or handling RPCs.

|----------------|
| NetGUID ObjRef |
    |----------------|
 |                |     
| Properties...  |
|                |  
| RPCs...        |
 |                |
 |----------------|
| </End Tag>     |
|----------------|

Member Enumeration Documentation

◆ ESkipRpcBehavior

enum class FObjectReplicator::ESkipRpcBehavior

strong

Enumerator
NeverSkip
SkipIfNotReady
AlwaysSkip

Constructor & Destructor Documentation

◆ FObjectReplicator()

FObjectReplicator::FObjectReplicator ( )

◆ ~FObjectReplicator()

FObjectReplicator::~FObjectReplicator ( )

Member Function Documentation

◆ CallRepNotifies()

void FObjectReplicator::CallRepNotifies ( bool bSkipIfChannelHasQueuedBunches ) const

◆ CanSkipUpdate()

bool FObjectReplicator::CanSkipUpdate ( FReplicationFlags Flags )

Returns: True if we've determined nothing needs to be updated / resent by the replicator, meaning we can safely skip updating it this frame.

◆ CleanUp()

void FObjectReplicator::CleanUp ( )

◆ CountBytes()

void FObjectReplicator::CountBytes ( FArchive & Ar ) const

◆ ExecutePendingTransactionalRPCs()

void FObjectReplicator::ExecutePendingTransactionalRPCs ( )

Execute any pending RPCs meant to be done within an AutoRTFM transaction.

See also: UNetDriver::PostTickDispatch

◆ ForceRefreshUnreliableProperties()

void FObjectReplicator::ForceRefreshUnreliableProperties ( )

◆ GetObject()

UObject * FObjectReplicator::GetObject ( ) const

inline

◆ GetWeakObjectPtr()

TWeakObjectPtr< UObject > FObjectReplicator::GetWeakObjectPtr ( ) const

inline

◆ InitRecentProperties()

void FObjectReplicator::InitRecentProperties ( uint8 * Source )

Recent/dirty related functions

Utility function to make a copy of the net properties

Parameters

Source - Memory to copy initial state from

◆ InitWithObject()

void FObjectReplicator::InitWithObject	(	UObject *	InObject,
		UNetConnection *	InConnection,
		bool	bUseDefaultState = `true`
	)

◆ IsDirtyForReplay()

bool FObjectReplicator::IsDirtyForReplay ( ) const

inline

◆ MoveMappedObjectToUnmapped()

bool FObjectReplicator::MoveMappedObjectToUnmapped ( const FNetworkGUID & GUID )

◆ PostNetReceive()

void FObjectReplicator::PostNetReceive ( )

inline

◆ PostReceivedBunch()

void FObjectReplicator::PostReceivedBunch ( )

◆ PostSendBunch()

void FObjectReplicator::PostSendBunch	(	FPacketIdRange &	PacketRange,
		uint8	bReliable
	)

◆ PreNetReceive()

void FObjectReplicator::PreNetReceive ( )

inline

◆ QueuePropertyRepNotify()

void FObjectReplicator::QueuePropertyRepNotify	(	UObject *	Object,
		FProperty *	Property,
		const int32	ElementIndex,
		TArray< uint8 > &	MetaData
	)

◆ QueueRemoteFunctionBunch()

void FObjectReplicator::QueueRemoteFunctionBunch	(	UFunction *	Func,
		FOutBunch &	Bunch
	)

◆ ReadyForDormancy()

bool FObjectReplicator::ReadyForDormancy ( bool bDebug = false )

◆ ReceivedBunch()

bool FObjectReplicator::ReceivedBunch	(	FNetBitReader &	Bunch,
		const FReplicationFlags &	RepFlags,
		const bool	bHasRepLayout,
		bool &	bOutHasUnmapped
	)

◆ ReceivedNak()

void FObjectReplicator::ReceivedNak ( int32 NakPacketId )

Packet was dropped

Handling NAKs / Property Retransmission.

Note, NACK handling only occurs on connections that "replicate" data, which is currently only Servers. RPC retransmission is handled elsewhere.

RepLayouts:

As we send properties through FRepLayout the is a Changelist Manager that is shared
between all connections tracks sets of properties that were recently changed (history items),
as well as one aggregate set of all properties that have ever been sent.

Each Sending Rep State, which is connection unique, also tracks the set of changed
properties. These history items will only be created when replicating the object,
so there will be fewer of them in general, but they will still contain any properties
that compared differently (not *just* the properties that were actually replicated).

Whenever a NAK is received, we will iterate over the SendingRepState changelist
and mark any of the properties sent in the NAKed packet for retransmission.

The next time Properties are replicated for the Object, we will merge in any changelists
from NAKed history items.

Custom Delta Properties:

For Custom Delta Properties (CDP), we rely primarily on FPropertyRetirements and INetDeltaBaseState
for tracking property retransmission.

INetDeltaBaseStates are used to tracked internal state specific to a given type of CDP.
For example, Fast Array Replicators will use FNetFastTArrayBaseState, or some type
derived from that.

When an FObjectReplicator is created, we will create an INetDeltaBaseState for every CDP,
as well as a dummy FPropertyRetirement. This Property Retirement is used as the head
of a linked list of Retirements, and is generally never populated with any useful information.

Every time we replicate a CDP, we will pass in the most recent Base State, and we will be
returned a new CDP. If data is actually sent, then we will create a new Property Retirement,
adding it as the tail of our linked list. The new Property Retirement will also hold a reference
to the old INetDeltaBaseState (i.e., the state of the CDP before it replicated its properties).

Just before replicating, we will go through and free any ACKed FPropertyRetirments (see
UpdateAckedRetirements).

After replicating, we will cache off the returned Base State to be used as the "old" state
the next time the property is replicated.

Whenever a NAK is received, we will run through our Property Retirements. Any retirements
that predate the NACK will be removed and treated as if they were ACKs. The first
retirement that is found to be within the NAKed range will have its INetDeltaBaseState
restored (which should be the state before the NAKed packet was sent), and then
that retirement as well as all remaining will be removed.

The onus is then on the CDP to resend any necessary properties based on its current / live
state and the restored Net Delta Base State.

Fast Array Properties:

Fast Array Properties are implemented as Custom Delta Properties (CDP). Therefore, they mostly
follow the flow laid out above.

FNetFastTArrayBaseState is the basis for all Fast Array Serializer INetDeltaBaseStates.
This struct tracks the Replication Key of the Array, the ID to Replication Key map of individual
Array Items, and a History Number.

As we replicate Fast Array Properties, we use the Array Replication key to see if anything
is possibly dirty in the Array and the ID to Replication map to see which Array Element
items actually are dirty. A mismatch between the Net Base State Key and the Key stored on
the live Fast Array (either the Array Replication Key, or any Item Key) is how we determine
if the Array or Items is dirty.

Whenever a NAK is received, our Old Base State will be reset to the last known ACKed value,
as described in the CDP section above. This means that our Array Replication Key and ID To
Item Replication Key should be reset to those states, forcing a mismatch the next time we
replicate if anything has changed.

When net.SupportFastArrayDelta is enabled, we perform an additional step in which we actually
compare the properties of dirty items. This is very similar to normal Property replication
using RepLayouts, and leverages most of the same code.

This includes tracking history items just like Rep Layout. Instead of tracking histories per
Sending Rep State / Per Connection, we just manage a single set of Histories on the Rep
Changelist Mgr. Changelists are stored per Fast Array Item, and are referenced via ID.

Whenever we go to replicate a Fast Array Item, we will merge together all changelists since
we last sent that item, and send those accumulated changes.

This means that property retransmission for Fast Array Items is an amalgamation of Rep Layout
retransmission and CDP retransmission.

Whenever a NAK is received, our History Number should be reset to the last known ACKed value,
and that should be enough to force us to accumulate any of the NAKed item changelists.

◆ ReceivedRPC() [1/2]

bool FObjectReplicator::ReceivedRPC	(	FNetBitReader &	Reader,
		const FReplicationFlags &	RepFlags,
		const FFieldNetCache *	FieldCache,
		const bool	bCanDelayRPC,
		bool &	bOutDelayRPC,
		TSet< FNetworkGUID > &	OutUnmappedGuids
	)

inline

◆ ReceivedRPC() [2/2]

bool FObjectReplicator::ReceivedRPC	(	FNetBitReader &	Reader,
		TSet< FNetworkGUID > &	OutUnmappedGuids,
		bool &	bOutSkippedRpcExec,
		const FReplicationFlags &	RepFlags,
		const FFieldNetCache *	FieldCache,
		ESkipRpcBehavior	SkipRpcBehavior
	)

Parameters

Reader	the buffer that contains the RPC (this function reads RPC parameters from the current position)
OutUnmappedGuids	any GUIDs that are not yet resolvable because we do not have the data (yet)
bOutSkippedRpcExec	did we skip execution of this RPC? If so, the caller must handle execution (e.g. delay).
RepFlags	the replication flags (state) of the replicated object
FieldCache	the RPC FieldCache used to speed-up property lookups. This cannot be null.
SkipRpcBehavior	under what circumstances should we skip the execution of the RPC?

Returns: True if the Reader is still valid. False if the Reader should be abandoned.

See also: ReceivedBunch(), UpdateUnmappedObjects()

◆ ReleaseStrongReference()

void FObjectReplicator::ReleaseStrongReference ( )

inline

◆ ReplicateCustomDeltaProperties()

void FObjectReplicator::ReplicateCustomDeltaProperties	(	FNetBitWriter &	Bunch,
		FReplicationFlags	RepFlags,
		bool &	bSkippedPropertyCondition
	)

◆ ReplicateProperties() [1/2]

bool FObjectReplicator::ReplicateProperties	(	FOutBunch &	Bunch,
		FReplicationFlags	RepFlags
	)

◆ ReplicateProperties() [2/2]

bool FObjectReplicator::ReplicateProperties	(	FOutBunch &	Bunch,
		FReplicationFlags	RepFlags,
		FNetBitWriter &	Writer
	)

◆ ReplicateProperties_r()

bool FObjectReplicator::ReplicateProperties_r	(	FOutBunch &	Bunch,
		FReplicationFlags	RepFlags,
		FNetBitWriter &	Writer
	)

Replicates properties to the Bunch. Returns true if it wrote anything

◆ ResetReplayDirtyTracking()

void FObjectReplicator::ResetReplayDirtyTracking ( )

inline

◆ SendCustomDeltaProperty()

bool FObjectReplicator::SendCustomDeltaProperty	(	UObject *	InObject,
		uint16	CustomDeltaProperty,
		FNetBitWriter &	OutBunch,
		TSharedPtr< INetDeltaBaseState > &	NewFullState,
		TSharedPtr< INetDeltaBaseState > &	OldState
	)

◆ SetObject()

void FObjectReplicator::SetObject ( UObject * NewObj )

inline

◆ StartBecomingDormant()

void FObjectReplicator::StartBecomingDormant ( )

◆ StartReplicating()

void FObjectReplicator::StartReplicating ( class UActorChannel * InActorChannel )

◆ StopReplicating()

void FObjectReplicator::StopReplicating ( class UActorChannel * InActorChannel )

◆ UpdateGuidToReplicatorMap()

void FObjectReplicator::UpdateGuidToReplicatorMap ( )

◆ UpdateUnmappedObjects()

void FObjectReplicator::UpdateUnmappedObjects ( bool & bOutHasMoreUnmapped )

◆ ValidateAgainstState()

bool FObjectReplicator::ValidateAgainstState ( const UObject * ObjectState )

Takes Data, and compares against shadow state to log differences

◆ WritePropertyHeaderAndPayload()

void FObjectReplicator::WritePropertyHeaderAndPayload	(	UObject *	Object,
		FProperty *	Property,
		FNetFieldExportGroup *	NetFieldExportGroup,
		FNetBitWriter &	Bunch,
		FNetBitWriter &	Payload
	)		const

Member Data Documentation

◆ bForceUpdateUnmapped

uint32 FObjectReplicator::bForceUpdateUnmapped

True if we need to do an unmapped check next frame.

◆ bHasReplicatedProperties

uint32 FObjectReplicator::bHasReplicatedProperties

Whether or not we've already replicated properties this frame.

◆ bLastUpdateEmpty

uint32 FObjectReplicator::bLastUpdateEmpty

True if last update (ReplicateActor) produced no replicated properties

◆ bOpenAckCalled

uint32 FObjectReplicator::bOpenAckCalled

Whether or not the Actor Channel on which we're replicating has been Opened / Acked by the receiver.

◆ bSentSubObjectCreation

uint32 FObjectReplicator::bSentSubObjectCreation

Is this a subobject replicator and have we sent the creation data yet.

◆ ChangelistMgr

TSharedPtr<class FReplicationChangelistMgr> FObjectReplicator::ChangelistMgr

◆ CheckpointRepState

TUniquePtr<FRepState> FObjectReplicator::CheckpointRepState

◆ Connection

UNetConnection* FObjectReplicator::Connection

Connection this replicator was created on.

◆ ObjectClass

TObjectPtr<UClass> FObjectReplicator::ObjectClass

◆ ObjectNetGUID

FNetworkGUID FObjectReplicator::ObjectNetGUID

Net GUID for the object we're replicating.

◆ ObjectPtr

UObject* FObjectReplicator::ObjectPtr

◆ OwningChannel

class UActorChannel* FObjectReplicator::OwningChannel

The Actor Channel that we're replicating on. This expected to be owned by Connection.

◆ PendingLocalRPCs

TArray<FRPCPendingLocalCall> FObjectReplicator::PendingLocalRPCs

Information on RPCs that have been received but not yet executed

◆ ReferencedGuids

TSet<FNetworkGUID> FObjectReplicator::ReferencedGuids

◆ RemoteFuncInfo

TArray<FRPCCallInfo> FObjectReplicator::RemoteFuncInfo

Meta information on pending net RPCs (to be sent)

◆ RemoteFunctions

FOutBunch* FObjectReplicator::RemoteFunctions

◆ RepLayout

TSharedPtr<FRepLayout> FObjectReplicator::RepLayout

◆ RepState

TUniquePtr<FRepState> FObjectReplicator::RepState

◆ TrackedGuidMemoryBytes

int32 FObjectReplicator::TrackedGuidMemoryBytes

The amount of memory (in bytes) that we're using to track Unmapped GUIDs.

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

Engine/Source/Runtime/Engine/Public/Net/DataReplication.h
Engine/Source/Runtime/Engine/Private/DataReplication.cpp

Classes

Public Types

Public Member Functions

Public Attributes

Detailed Description

Member Enumeration Documentation

◆ ESkipRpcBehavior

Constructor & Destructor Documentation

◆ FObjectReplicator()

◆ ~FObjectReplicator()

Member Function Documentation

◆ CallRepNotifies()

◆ CanSkipUpdate()

◆ CleanUp()

◆ CountBytes()

◆ ExecutePendingTransactionalRPCs()

◆ ForceRefreshUnreliableProperties()

◆ GetObject()

◆ GetWeakObjectPtr()

◆ InitRecentProperties()

◆ InitWithObject()

◆ IsDirtyForReplay()

◆ MoveMappedObjectToUnmapped()

◆ PostNetReceive()

◆ PostReceivedBunch()

◆ PostSendBunch()

◆ PreNetReceive()

◆ QueuePropertyRepNotify()

◆ QueueRemoteFunctionBunch()

◆ ReadyForDormancy()

◆ ReceivedBunch()

◆ ReceivedNak()

◆ ReceivedRPC() [1/2]

◆ ReceivedRPC() [2/2]

◆ ReleaseStrongReference()

◆ ReplicateCustomDeltaProperties()

◆ ReplicateProperties() [1/2]

◆ ReplicateProperties() [2/2]

◆ ReplicateProperties_r()

◆ ResetReplayDirtyTracking()

◆ SendCustomDeltaProperty()

◆ SetObject()

◆ StartBecomingDormant()

◆ StartReplicating()

◆ StopReplicating()

◆ UpdateGuidToReplicatorMap()

◆ UpdateUnmappedObjects()

◆ ValidateAgainstState()

◆ WritePropertyHeaderAndPayload()

Member Data Documentation

◆ bForceUpdateUnmapped

◆ bHasReplicatedProperties

◆ bLastUpdateEmpty

◆ bOpenAckCalled

◆ bSentSubObjectCreation

◆ ChangelistMgr

◆ CheckpointRepState

◆ Connection

◆ ObjectClass

◆ ObjectNetGUID

◆ ObjectPtr

◆ OwningChannel

◆ PendingLocalRPCs

◆ ReferencedGuids

◆ RemoteFuncInfo

◆ RemoteFunctions

◆ RepLayout

◆ RepState

◆ TrackedGuidMemoryBytes