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+
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Rosegarden
+    A MIDI and audio sequencer and musical notation editor.
+
+    This program is Copyright 2000-2008
+        Guillaume Laurent   <[email protected]>,
+        Chris Cannam        <[email protected]>,
+        Richard Bown        <[email protected]>
+
+    The moral rights of Guillaume Laurent, Chris Cannam, and Richard
+    Bown to claim authorship of this work have been asserted.
+
+    Other copyrights also apply to some parts of this work.  Please
+    see the AUTHORS file and individual file headers for details.
+
+    This program is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License as
+    published by the Free Software Foundation; either version 2 of the
+    License, or (at your option) any later version.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef _RG_MULTIVIEWCOMMANDHISTORY_H_
+#define _RG_MULTIVIEWCOMMANDHISTORY_H_
+
+#include <set>
+#include <stack>
+#include <qobject.h>
+
+
+class QString;
+class KCommand;
+class KActionCollection;
+
+
+namespace Rosegarden
+{
+
+
+
+/**
+ * The MultiViewCommandHistory class is much like KCommandHistory in
+ * that it stores a list of executed commands and maintains Undo and
+ * Redo actions synchronised with those commands.
+ *
+ * The difference is that MultiViewCommandHistory allows you to
+ * associate more than one Undo and Redo action with the same command
+ * history, and it keeps them all up-to-date at once.  This makes it
+ * effective in systems where multiple views may be editing the same
+ * data at once.
+ */
+
+class MultiViewCommandHistory : public QObject
+{
+    Q_OBJECT
+public:
+
+    MultiViewCommandHistory();
+    virtual ~MultiViewCommandHistory();
+
+    void clear();
+    
+    void attachView(KActionCollection *collection);
+    void detachView(KActionCollection *collection);
+
+    void addCommand(KCommand *command, bool execute = true);
+    
+    /// @return the maximum number of items in the undo history
+    int undoLimit() { return m_undoLimit; }
+
+    /// Set the maximum number of items in the undo history
+    void setUndoLimit(int limit);
+
+    /// @return the maximum number of items in the redo history
+    int redoLimit() { return m_redoLimit; }
+
+    /// Set the maximum number of items in the redo history
+    void setRedoLimit(int limit);
+    
+public slots:
+    /**
+     * Remember when you saved the document.
+     * Call this right after saving the document. As soon as
+     * the history reaches the current index again (via some
+     * undo/redo operations) it will emit @ref documentRestored
+     * If you implemented undo/redo properly the document is
+     * the same you saved before.
+     */
+    virtual void documentSaved();
+
+protected slots:
+    void slotUndo();
+    void slotRedo();
+    void slotUndoAboutToShow();
+    void slotUndoActivated(int);
+    void slotRedoAboutToShow();
+    void slotRedoActivated(int);
+
+signals:
+    /**
+     * This is emitted every time a command is executed
+     * (whether by addCommand, undo or redo).
+     * You can use this to update the GUI, for instance.
+     */
+    void commandExecuted(KCommand *);
+
+    /**
+     * This is emitted every time a command is executed
+     * (whether by addCommand, undo or redo).
+     *
+     * It should be connected to the update() slot of widgets
+     * which need to repaint after a command
+     */
+    void commandExecuted();
+
+    /**
+     * This is emitted every time we reach the index where you
+     * saved the document for the last time. See @ref documentSaved
+     */
+    void documentRestored();
+
+private:
+    //--------------- Data members ---------------------------------
+
+    typedef std::set<KActionCollection *> ViewSet;
+    ViewSet m_views;
+
+    typedef std::stack<KCommand *> CommandStack;
+    CommandStack m_undoStack;
+    CommandStack m_redoStack;
+
+    int m_undoLimit;
+    int m_redoLimit;
+    int m_savedAt;
+
+    void updateButtons();
+    void updateButton(bool undo, const QString &name, CommandStack &stack);
+    void updateMenu(bool undo, const QString &name, CommandStack &stack);
+    void clipCommands();
+
+    void clipStack(CommandStack &stack, int limit);
+    void clearStack(CommandStack &stack);
+};
+
+
+
+}
+
+#endif