* This interface is implemented by an object that wants to * manage/track transactions. */ [scriptable, uuid(58e330c2-7b48-11d2-98b9-00805f297d89)] interface nsITransactionManager : nsISupports { /** * 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. * @param aTransaction the transaction to do. */ void doTransaction(in nsITransaction aTransaction); /** * Pops the topmost transaction on the undo stack, calls it's * undoTransaction() method, then pushes it on the redo stack. */ void undoTransaction(); /** * Pops the topmost transaction on the redo stack, calls it's * redoTransaction() method, then pushes it on the undo stack. */ void redoTransaction(); /** * Clears the undo and redo stacks. */ void clear(); /** * 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(). */ void beginBatch(); /** * Turns off the transaction manager's batch mode. */ void endBatch(); /** * The number of items on the undo stack. */ readonly attribute long numberOfUndoItems; /** * The number of items on the redo stack. */ readonly attribute long numberOfRedoItems; /** * 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 aMaxCount 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. */ attribute long maxTransactionCount; /** * 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. */ nsITransaction peekUndoStack(); /** * 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. */ nsITransaction peekRedoStack(); /** * Returns the list of transactions on the undo stack. Note that the * transaction at the top of the undo stack will actually be at the * index 'n-1' in the list, where 'n' is the number of items in the list. */ nsITransactionList getUndoList(); /** * Returns the list of transactions on the redo stack. Note that the * transaction at the top of the redo stack will actually be at the * index 'n-1' in the list, where 'n' is the number of items in the list. */ nsITransactionList getRedoList(); /** * Adds a listener to the transaction manager's notification list. Listeners * are notified whenever a transaction is done, undone, or redone. *
* The listener's AddRef() method is called. * @param aListener the lister to add. */ void AddListener(in nsITransactionListener aListener); /** * Removes a listener from the transaction manager's notification list. *
* The listener's Release() method is called. * @param aListener the lister to remove. */ void RemoveListener(in nsITransactionListener aListener); };