File indexing completed on 2024-12-22 04:10:03

 /*
  *  SPDX-FileCopyrightText: 2020 Dmitry Kazakov <dimula73@gmail.com>
  *
  *  SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 
 #ifndef KISASYNCHRONOUSLYMERGEABLECOMMANDINTERFACE_H
 #define KISASYNCHRONOUSLYMERGEABLECOMMANDINTERFACE_H
 
 class KUndo2Command;
 
 /**
  * A special base class for commands that should be able to merge
  * (compress) when used inside KisProcessingApplicator (or anything
  * else that uses KisSavedMacroCommand).
  *
  * KisProcessingApplicator generates many commands, but undo stack
  * wants only one command to represent user's action. That is why
  * the action is wrapped into KisSavedMacroCommand. This macro command
  * class has a special algorithm for merging an action consisting of
  * multiple commands. This algorithm must know if **all** the commands
  * of the macro can be merged before doing the actual merge. Using
  * KUndo2Command::mergeWith() is not possible for this purpose, because
  * it merges commands right away and one cannot undo that.
  *
  * \see KisSavedMacroCommand::mergeWith()
  * \see example in KisNodeCompositeOpCommand
  */
 class KisAsynchronouslyMergeableCommandInterface
 {
 public:
     virtual ~KisAsynchronouslyMergeableCommandInterface();
 
     /**
      * @return true if \p command can be merged with (*this) command
      *         using KUndo2Command::mergeWith() call.
      *
      * WARNING: if canMergeWith() returned true, then mergeWith() must
      *          also return true. Otherwise KisSavedMacroCommand will
      *          be able to enter inconsistent state and assert.
      */
     virtual bool canMergeWith(const KUndo2Command *command) const = 0;
 };
 
 #endif // KISASYNCHRONOUSLYMERGEABLECOMMANDINTERFACE_H