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  3. UTransBuffer

UTransBuffer

Transaction tracking system, manages the undo and redo buffer.

Unreal Engine C++ API Reference > Editor > UnrealEd > Editor

Inheritance Hierarchy

References

   
Module UnrealEd
Header /Engine/Source/Editor/UnrealEd/Classes/Editor/TransBuffer.h
Include #include "Editor/TransBuffer.h"

Syntax

class UTransBuffer : public UTransactor

Remarks

Transaction tracking system, manages the undo and redo buffer.

Variables

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

Functions

  Type Name Description
Public function Static void  
Protected function int32

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

 Implementation of the begin function. Used to create a specific transaction type
Public function Const void Validates the state of the transaction buffer.
Public function void

Initialize ( SIZE_T InMaxMemory
)

 Constructor.
Public function UTransBuffer::FOnTransactorBeforeRedoUndo TBaseMulticastDelegate_OneParam  
Protected function void

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

  
Public function UTransBuffer::FOnTransactorRedo TBaseMulticastDelegate_TwoParams

OnRedo ()

  
Public function UTransBuffer::FOnTransactorTransactionStateChanged TBaseMulticastDelegate_TwoParams  
Public function UTransBuffer::FOnTransactorUndo TBaseMulticastDelegate_TwoParams

OnUndo ()

  
Public function UTransBuffer::FOnTransactorUndoBufferChanged TBaseMulticastDelegate_NoParams  

Overridden from UTransactor

  Type Name Description
Public function Virtual int32

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

 Begins a new undo transaction.
Public function Virtual void

Cancel ( int32 StartIndex
)

 Cancels the current transaction, no longer capture actions to be placed in the undo buffer.
Public function Virtual bool

CanRedo ( FText* Text
)

 Determines whether the redo option should be selectable.
Public function Virtual bool

CanUndo ( FText* Text
)

 Determines whether the undo option should be selectable.
Public function Virtual void Clears all undo barriers.
Public function Virtual Const bool  
Public function Virtual bool Disables the transaction buffer from serializing the set of objects it references.
Public function Virtual bool Enables the transaction buffer to serialize the set of objects it references.
Public function Virtual int32

End ()

 Attempts to close an undo transaction. Only successful if the transaction's action counter is 1.
Public function Virtual Const int32

FindTransactionIndex ( const FGuid& TransactionId
)

 Gets the transaction queue index from its TransactionId.
Public function Virtual Const int32 Gets the current undo barrier's position in transaction queue
Public function Virtual Const int32 Gets the current length of the transaction queue.
Public function Virtual FTransactionContext Returns the description of the redo action that will be performed next.
Public function Virtual Const const FTransaction *

GetTransaction ( int32 QueueIndex
)

 Gets the transaction at the specified queue index.
Public function Virtual FTransactionContext

GetUndoContext ( bool bCheckWhetherUndoPossible
)

 Returns the description of the undo action that will be performed next.
Public function Virtual Const int32 Gets the number of transactions that were undone and can be redone.
Public function Virtual Const SIZE_T Determines the amount of data currently stored by the transaction buffer.
Public function Virtual bool Returns whether there are any active actions; i.e. whether actions are currently being captured into the undo buffer.
Public function Virtual Const bool Checks if a specific object is referenced by the transaction buffer
Public function Virtual bool Wrapper for checking if the transaction buffer is allowed to serialize object references.
Public function Virtual Const bool

IsObjectTransacting ( const UObject* Object
)

 Checks if a specific object is in the transaction currently underway
Public function Virtual bool

Redo ()

 Executes an redo transaction, redoing all actions contained by that transaction.
Public function Virtual void Removes the last set undo barrier from the transaction buffer.
Public function Virtual void

Reset ( const FText& Reason
)

 Resets the entire undo buffer; deletes all undo transactions.
Public function Virtual void Set passed object as the primary context object for transactions
Public function Virtual void Sets an undo barrier at the current point in the transaction buffer.
Public function Virtual bool

Undo ( bool bCanRedo
)

 Executes an undo transaction, undoing all actions contained by that transaction.

Overridden from UObject

  Type Name Description
Public function Virtual void Called to finish destroying the object.
Public function Virtual void Handles reading, writing, and reference collecting using FArchive.

Classes

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

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