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  3. FEditorBulkData

FEditorBulkData

The goal of this class is to provide an editor time version of BulkData that will work with the asset virtualization system.

API > API/Runtime > API/Runtime/CoreUObject > API/Runtime/CoreUObject/Serialization

References

   
Module CoreUObject
Header /Engine/Source/Runtime/CoreUObject/Public/Serialization/EditorBulkData.h
Include #include "Serialization/EditorBulkData.h"

Syntax

class FEditorBulkData

Remarks

The goal of this class is to provide an editor time version of BulkData that will work with the asset virtualization system.

Assuming that the DDC is hot, the virtualized payloads are accessed relatively infrequently, usually when the package is being edited in the editor in some manner. So the payload access is designed around this. If the data is frequently accessed when running the editor then the user would not gain from having it virtualized as they would end up pulling it immediately anyway.

The biggest difference with normal bulkdata is that the access times might be significantly longer if the payload is not readily available which is why the only way to access the payload is by a TFuture or a callback so that the caller is forced to consider how to handle the potential stall and hopefully organize their code in such a way that the time lag is not noticeable to the user.

The second biggest difference is that the caller will own the payload memory once it is returned to them, unlike the old bulkdata class which would retain ownership. Which forces the calling code to be in control of when the memory is actually allocated and for how long. With the old bulkdata class a single access would leave that memory allocated in a non-obvious way and would lead to memory bloats within the editor.

The method ::GetGuid can be used to access a unique identifier for the payload, currently it is based on the payload itself, so that two objects with the same payload would both have the same Guid. The intent is that we would be able to share local copies of the payload between branches to reduce the cost of having multiple branches with similar data on the same machine.

Updating the bulkdata: Unlike the older bulkdata system, EditorBulkData does not support any lock/unlock mechanism, instead the internal data is updated via a single call to ::UpdatePayload and the data is retrieved via a single call to ::GetPayload.

For examples see the "System.CoreUObject.Serialization.EditorBulkData.UpdatePayload" test found in Engine\Source\Runtime\CoreUObject\Private\Tests\Serialization\EditorBulkDataTests.cpp.

Thread Safety:

The class should be thread safe in that you can call the public methods on multiple threads at once and expect things to work. However if you were to call GetPayloadSize() before calling ::GetPayload() on one thread it would be possible for a call to ::UpdatePayload() to occur on another thread in between those two calls, meaning that the size you got might not be the correct size as the payload returned. If you need that level of thread safety it would be up to you to manage it at a higher level. It would however be safe to pass a copy of your FEditorBulkData to a background task rather than a reference. The copy would either be able to load the payload from disk, pull it from virtualized storage or if the source bulkdata is holding the payload in memory it will just take a reference to that payload rather than making a copy. In this way you can be sure of the state of the FEditorBulkData on the background task as future edits to the original bulkdata will not affect it.The base class with no type

Constructors

  Type Name Description
Public function    
Public function    
Public function  

FEditorBulkData ( const FEditorBulkData& Other
)

  
Protected function    

Destructors

  Type Name Description
Public function    

Functions

  Type Name Description
Public function Const bool Return true if the bulkdata has a source location that persists between editor processes (package file or virtualization).
Public function Const FEditorBulkData Make a torn-off copy of this bulk data.
Public function void

CreateFromBulkData ( FBulkData& BulkData,
const FGuid& Guid,
UObject* Owner
)

 Convenience method to make it easier to convert from FBulkData to FEditorBulkData and sets the Guid
Public function void Fix legacy content that created the Id from non-unique Guids.
Public function void

DetachFromDisk ( FArchive* Ar,
bool bEnsurePayloadIsLoaded
)

 Removes the ability for the bulkdata object to load it's payload from disk (if it was doing so)
Public function Const bool Returns if the payload would require loading in order to be accessed.
Public function Const void

GetBulkDataVersions ( FArchive& InlineArchive,
FPackageFileVersion& OutUEVersion,
int32& OutLicenseeUEVersion,
FCustomVersionContainer& OutCustomVersions
)

 Get the versions used in the file containing the payload.
Public function Const TFuture< FCompressedBuffer > Returns an immutable FCompressedBuffer reference to the payload data.
Public function Const FGuid Returns a unique identifier for the object itself.
Public function Const TFuture< FSharedBuffer > Returns an immutable FCompressedBuffer reference to the payload data.
Public function Const const FIoHash & Returns an unique identifier for the content of the payload.
Public function Const int64 Returns the size of the payload in bytes.
Public function Const bool Returns true if the bulkdata object contains a valid payload greater than zero bytes in size.
Public function Const bool Return whether the BulkData has legacy payload id that needs to be updated from loaded payload before it can be used in DDC.
Public function Const bool Return whether the BulkData is an in-memory payload without a persistent source location.
Public function Const bool

LocationMatches ( const FEditorBulkData& Other
)

 Return whether *this has the same source for the bulkdata (e.g. identical file locations if from file) as Other
Public function void

Reset ()

 Reset to a truly empty state
Public function void

Serialize ( FArchive& Ar,
UObject* Owner,
bool bAllowRegister
)

 Used to serialize the bulkdata to/from a FArchive
Public function void Used to serialize the bulkdata to/from a limited cache system used by the BulkDataRegistry.
Public function void Sets the compression options to be applied to the payload during serialization.
Public function void Sets the compression options to be applied to the payload during serialization.
Public function void

TearOff ()

 Set this BulkData into Torn-Off mode.
Public function void TODO: Not sure if there is a scenario where we can reload the payload off disk but it is also in memory.and so this might not really do anything anymore.
Public function void

UpdatePayload ( FCompressedBuffer InPayload,
UObject* Owner
)

 Replaces the existing payload (if any) with a new one.
Public function void

UpdatePayload ( FSharedBuffer InPayload,
UObject* Owner
)

 Replaces the existing payload (if any) with a new one.
Public function void

UpdatePayload ( FSharedBufferWithID InPayload,
UObject* Owner
)

 Allows the existing payload to be replaced with a new one.
Public function void Load the payload and set the correct payload id, if the bulkdata has a PlaceholderPayloadId.
Public function void Update the Owner of this BulkData in the BulkDataRegistry to include the Owner information.

Operators

  Type Name Description
Public function FEditorBulkData &

operator= ( const FEditorBulkData& Other
)

  
Public function FEditorBulkData &  

Classes

  Type Name Description
Public struct FSharedBufferWithID Utility struct used to compute the Payload ID before calling UpdatePayload  

Enums

  Type Name Description
Private enum EFlags Flags used to store additional meta information about the bulk data  
Private enum ErrorVerbosity Used to control what level of error reporting we return from some methods  
Protected enum ETornOff    

Constants

Name Description
TransientFlags A common grouping of EFlags

Deprecated Functions

  Type Name Description
Public function FCustomVersionContainer

GetCustomVersions ( FArchive& InlineArchive
)

 Call GetBulkDataVersions instead.
Public function void

SetVirtualizationOptOut ( bool bOptOut
)

 SetVirtualizationOptOut is an internal feature for development and will be removed without warning!

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