editor/txmgr/nsITransaction.idl

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "nsISupports.idl"
   7
   8 /*
   9  * The nsITransaction interface.
  10  * <P>
  11  * This interface is implemented by an object that needs to
  12  * execute some behavior that must be tracked by the transaction manager.
  13  */
  14 [scriptable, uuid(58e330c1-7b48-11d2-98b9-00805f297d89)]
  15 interface nsITransaction : nsISupports
  16 {
  17   /**
  18    * Executes the transaction.
  19    */
  20   void doTransaction();
  21
  22   /**
  23    * Restores the state to what it was before the transaction was executed.
  24    */
  25   void undoTransaction();
  26
  27   /**
  28    * Executes the transaction again. Can only be called on a transaction that
  29    * was previously undone.
  30    * <P>
  31    * In most cases, the redoTransaction() method will actually call the
  32    * doTransaction() method to execute the transaction again.
  33    */
  34   void redoTransaction();
  35
  36   /**
  37    * The transaction's transient state. This attribute is checked by
  38    * the transaction manager after the transaction's Execute() method is called.
  39    * If the transient state is false, a reference to the transaction is
  40    * held by the transaction manager so that the transactions' undoTransaction()
  41    * and redoTransaction() methods can be called. If the transient state is
  42    * true, the transaction manager returns immediately after the transaction's
  43    * doTransaction() method is called, no references to the transaction are
  44    * maintained. Transient transactions cannot be undone or redone by the
  45    * transaction manager.
  46    */
  47   readonly attribute boolean isTransient;
  48
  49   /**
  50    * Attempts to merge a transaction into "this" transaction. Both transactions
  51    * must be in their undo state, doTransaction() methods already called. The
  52    * transaction manager calls this method to coalesce a new transaction with
  53    * the transaction on the top of the undo stack.
  54    * This method returns a boolean value that indicates the merge result.
  55    * A true value indicates that the transactions were merged successfully,
  56    * a false value if the merge was not possible or failed. If true,
  57    * the transaction manager will Release() the new transacton instead of
  58    * pushing it on the undo stack.
  59    * @param aTransaction the previously executed transaction to merge.
  60    */
  61   boolean merge(in nsITransaction aTransaction);
  62 };
  63