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  3. UTransBuffer

UTransBuffer

Transaction tracking system, manages the undo and redo buffer.

API > API/Editor > API/Editor/UnrealEd

Transaction tracking system, manages the undo and redo buffer.

   
Name UTransBuffer
Type class
Header File /Engine/Source/Editor/UnrealEd/Classes/Editor/TransBuffer.h
Include Path #include "Editor/TransBuffer.h"

Syntax

UCLASS (Transient, MinimalAPI)  
class UTransBuffer : public UTransactor

Inheritance Hierarchy

Classes

Name Remarks
FOnTransactorBeforeRedoUndo Gets an event delegate that is executed when a redo operation is being attempted.
FOnTransactorRedo Gets an event delegate that is executed when a redo operation is being attempted.
FOnTransactorTransactionStateChanged Gets an event delegate that is executed when a transaction state changes.
FOnTransactorUndo Gets an event delegate that is executed when a undo operation is being attempted.
FOnTransactorUndoBufferChanged Gets an event delegate that is executed when the undo buffer changed.

Variables

Public

Name Type Remarks Include Path Unreal Specifiers
ActiveCount int32 Number of actions in the current transaction Editor/TransBuffer.h  
ActiveRecordCounts TArray< int32 > The cached count of the number of object records each time a transaction is begun Editor/TransBuffer.h  
MaxMemory SIZE_T Maximum number of bytes the transaction buffer is allowed to occupy Editor/TransBuffer.h  
ResetReason FText Text describing the reason that the undo buffer is empty Editor/TransBuffer.h  
UndoBarrierStack TArray< int32 > Undo barrier stack Editor/TransBuffer.h  
UndoBuffer TArray< TSharedRef< FTransaction > > Variables. Editor/TransBuffer.h  
UndoCount int32 Number of transactions that have been undone, and are eligible to be redone Editor/TransBuffer.h  

Protected

Name Type Remarks Include Path Unreal Specifiers
BeforeRedoUndoDelegate FOnTransactorBeforeRedoUndo Holds an event delegate that is executed before a redo or undo operation is attempted. Editor/TransBuffer.h  
CurrentTransaction FTransaction * Reference to the current transaction, nullptr when not transacting: Editor/TransBuffer.h  
DisallowObjectSerialization int32 Controls whether the transaction buffer is allowed to serialize object references Editor/TransBuffer.h  
PreviousUndoCount int32 Cached previous undo count while a transaction is being built in case we cancel it and want to restore the previous undo buffer. Editor/TransBuffer.h  
RedoDelegate FOnTransactorRedo Holds an event delegate that is executed when a redo operation is being attempted. Editor/TransBuffer.h  
RemovedTransactions TArray< TSharedRef< FTransaction > > The list of transactions that were removed when a transaction was begun in case it is canceled and we want to restore the original state. Editor/TransBuffer.h  
TransactionStateChangedDelegate FOnTransactorTransactionStateChanged Holds an event delegate that is executed when a transaction state changes. Editor/TransBuffer.h  
UndoBufferChangedDelegate FOnTransactorUndoBufferChanged Holds an event delegate that is executed when the undo buffer changed. Editor/TransBuffer.h  
UndoDelegate FOnTransactorUndo Holds an event delegate that is executed when a undo operation is being attempted. Editor/TransBuffer.h  

Functions

Public

Name Remarks Include Path Unreal Specifiers

void CheckState()

 Validates the state of the transaction buffer. Editor/TransBuffer.h  

void Initialize ( SIZE_T InMaxMemory
)

 Constructor. Editor/TransBuffer.h  

UTransBuffer::FOnTransactorBeforeRedoUndo TBaseMulticastDelegate_OneParam OnBeforeRedoUndo()

   Editor/TransBuffer.h  

UTransBuffer::FOnTransactorRedo TBaseMulticastDelegate_TwoParams OnRedo()

   Editor/TransBuffer.h  

UTransBuffer::FOnTransactorTransactionStateChanged TBaseMulticastDelegate_TwoParams OnTransactionStateChanged()

   Editor/TransBuffer.h  

UTransBuffer::FOnTransactorUndo TBaseMulticastDelegate_TwoParams OnUndo()

   Editor/TransBuffer.h  

UTransBuffer::FOnTransactorUndoBufferChanged TBaseMulticastDelegate_NoParams OnUndoBufferChanged()

   Editor/TransBuffer.h  

Overridden from UTransactor

Name Remarks Include Path Unreal Specifiers

virtual int32 Begin ( const TCHAR* SessionContext,
const FText& Description
)

 Begins a new undo transaction. Editor/TransBuffer.h  

virtual void Cancel ( int32 StartIndex
)

 Cancels the current transaction, no longer capture actions to be placed in the undo buffer. Editor/TransBuffer.h  

virtual bool CanRedo ( FText* Text
)

 Determines whether the redo option should be selectable. Editor/TransBuffer.h  

virtual bool CanUndo ( FText* Text
)

 Determines whether the undo option should be selectable. Editor/TransBuffer.h  

virtual void ClearUndoBarriers()

 Clears all undo barriers. Editor/TransBuffer.h  

virtual bool ContainsPieObjects()

   Editor/TransBuffer.h  

virtual bool DisableObjectSerialization()

 Disables the transaction buffer from serializing the set of objects it references. Editor/TransBuffer.h  

virtual bool EnableObjectSerialization()

 Enables the transaction buffer to serialize the set of objects it references. Editor/TransBuffer.h  

virtual int32 End()

 Attempts to close an undo transaction. Only successful if the transaction's action counter is 1. Editor/TransBuffer.h  

virtual int32 FindTransactionIndex ( const FGuid& TransactionId
) const

 Gets the transaction queue index from its TransactionId. Editor/TransBuffer.h  

virtual int32 GetCurrentUndoBarrier()

 Gets the current undo barrier's position in transaction queue Editor/TransBuffer.h  

virtual int32 GetQueueLength()

 Gets the current length of the transaction queue. Editor/TransBuffer.h  
Returns the description of the redo action that will be performed next. Editor/TransBuffer.h  

virtual const FTransaction * GetTransaction ( int32 QueueIndex
) const

 Gets the transaction at the specified queue index. Editor/TransBuffer.h  

virtual FTransactionContext GetUndoContext ( bool bCheckWhetherUndoPossible
)

 Returns the description of the undo action that will be performed next. Editor/TransBuffer.h  

virtual int32 GetUndoCount()

 Gets the number of transactions that were undone and can be redone. Editor/TransBuffer.h  

virtual SIZE_T GetUndoSize()

 Determines the amount of data currently stored by the transaction buffer. Editor/TransBuffer.h  

virtual bool IsActive()

 Returns whether there are any active actions; i.e. whether actions are currently being captured into the undo buffer. Editor/TransBuffer.h  

virtual bool IsObjectInTransactionBuffer ( const UObject* Object
) const

 Checks if a specific object is referenced by the transaction buffer Editor/TransBuffer.h  

virtual bool IsObjectSerializationEnabled()

 Wrapper for checking if the transaction buffer is allowed to serialize object references. Editor/TransBuffer.h  

virtual bool IsObjectTransacting ( const UObject* Object
) const

 Checks if a specific object is in the transaction currently underway Editor/TransBuffer.h  

virtual bool Redo()

 Executes an redo transaction, redoing all actions contained by that transaction. Editor/TransBuffer.h  

virtual void RemoveUndoBarrier()

 Removes the last set undo barrier from the transaction buffer. Editor/TransBuffer.h  

virtual void Reset ( const FText& Reason
)

 Resets the entire undo buffer; deletes all undo transactions. Editor/TransBuffer.h  

virtual void SetPrimaryUndoObject ( UObject* Object
)

 Set passed object as the primary context object for transactions Editor/TransBuffer.h  

virtual void SetUndoBarrier ()

 Sets an undo barrier at the current point in the transaction buffer. Editor/TransBuffer.h  

virtual bool Undo ( bool bCanRedo
)

 Executes an undo transaction, undoing all actions contained by that transaction. Editor/TransBuffer.h  

Overridden from UObject

Name Remarks Include Path Unreal Specifiers

virtual void FinishDestroy()

   Editor/TransBuffer.h  

virtual void Serialize ( FArchive& Ar
)

   Editor/TransBuffer.h  

Protected

Name Remarks Include Path Unreal Specifiers

int32 BeginInternal ( const TCHAR* SessionContext,
const FText& Description
)

 Implementation of the begin function. Used to create a specific transaction type Editor/TransBuffer.h  

void OnObjectsReinstanced ( const TMap< UObject*, UObject* >& OldToNewInstances
)

   Editor/TransBuffer.h  

Static

Name Remarks Include Path Unreal Specifiers

static void AddReferencedObjects ( UObject* InThis,
FReferenceCollector& Collector
)

   Editor/TransBuffer.h  

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