Interface nsITransactionManagerType

The nsITransactionManager interface.

This interface is implemented by an object that wants to manage/track transactions.

Hierarchy

Properties

maxTransactionCount numberOfRedoItems numberOfUndoItems

Methods

AddRef QueryInterface Release batchTopUndo beginBatch clear clearRedoStack clearUndoStack doTransaction endBatch peekRedoStack peekUndoStack redoTransaction removeTopUndo undoTransaction

Properties

maxTransactionCount

maxTransactionCount: number

Sets the maximum number of transaction items the transaction manager will maintain at any time. This is commonly referred to as the number of levels of undo.

Param

A value of -1 means no limit. A value of zero means the transaction manager will execute each transaction, then immediately release all references it has to the transaction without pushing it on the undo stack. A value greater than zero indicates the max number of transactions that can exist at any time on both the undo and redo stacks. This method will prune the necessary number of transactions on the undo and redo stacks if the value specified is less than the number of items that exist on both the undo and redo stacks.

Readonly numberOfRedoItems

numberOfRedoItems: number

The number of items on the redo stack.

Readonly numberOfUndoItems

numberOfUndoItems: number

The number of items on the undo stack.

Methods

AddRef

  • Increases the reference count for this interface. The associated instance will not be deleted unless the reference count is returned to zero.

    Returns

    The resulting reference count.

    Returns number

QueryInterface

  • Parameters

    • aIID: object
    • Optional aInstancePtr: object

    Returns any

  • A run time mechanism for interface discovery.

    Returns

    NS_OK if the interface is supported by the associated instance, NS_NOINTERFACE if it is not.

    aInstancePtr must not be null.

    Parameters

    • aIID: object

      [in] A requested interface IID

    • aInstancePtr: object

      [out] A pointer to an interface pointer to receive the result.

    Returns void

Release

  • Decreases the reference count for this interface. Generally, if the reference count returns to zero, the associated instance is deleted.

    Returns

    The resulting reference count.

    Returns number

batchTopUndo

  • Combines the transaction at the top of the undo stack (if any) with the preceding undo transaction (if any) into a batch transaction. Thus, a call to undoTransaction() will undo both transactions.

    Returns void

beginBatch

  • Turns on the transaction manager's batch mode, forcing all transactions executed by the transaction manager's doTransaction() method to be aggregated together until EndBatch() is called. This mode allows an application to execute and group together several independent transactions so they can be undone with a single call to undoTransaction().

    Parameters

    • aData: nsISupports

      An arbitrary nsISupports object that is associated with the batch. Can be retrieved from the undo or redo stacks.

    Returns void

clear

  • Clears the undo and redo stacks.

    Returns void

clearRedoStack

  • Clears the redo stack only.

    Returns void

clearUndoStack

  • Clears the undo stack only.

    Returns void

doTransaction

  • Calls a transaction's doTransaction() method, then pushes it on the undo stack.

    This method calls the transaction's AddRef() method. The transaction's Release() method will be called when the undo or redo stack is pruned or when the transaction manager is destroyed.

    Parameters

    • aTransaction: nsITransaction

      the transaction to do.

    Returns void

endBatch

  • Turns off the transaction manager's batch mode.

    Parameters

    • aAllowEmpty: boolean

      If true, a batch containing no children will be pushed onto the undo stack. Otherwise, ending a batch with no children will result in no transactions being pushed on the undo stack.

    Returns void

peekRedoStack

  • Returns an AddRef'd pointer to the transaction at the top of the redo stack. Callers should be aware that this method could return return a null in some implementations if there is a batch at the top of the redo stack.

    Returns nsITransaction

peekUndoStack

  • Returns an AddRef'd pointer to the transaction at the top of the undo stack. Callers should be aware that this method could return return a null in some implementations if there is a batch at the top of the undo stack.

    Returns nsITransaction

redoTransaction

  • Pops the topmost transaction on the redo stack, calls its redoTransaction() method, then pushes it on the undo stack.

    Returns void

removeTopUndo

  • Removes the transaction at the top of the undo stack (if any) without transacting.

    Returns void

undoTransaction

  • Pops the topmost transaction on the undo stack, calls its undoTransaction() method, then pushes it on the redo stack.

    Returns void

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