From b9aad1f15dc600e4dbe4c62d3fcced6363188ba3 Mon Sep 17 00:00:00 2001
From: zautrix <zautrix>
Date: Sat, 26 Jun 2004 19:01:18 +0000
Subject: Initial revision

---
(limited to 'kaddressbook/undo.h')

diff --git a/kaddressbook/undo.h b/kaddressbook/undo.h
new file mode 100644
index 0000000..843bc26
--- a/dev/null
+++ b/kaddressbook/undo.h
@@ -0,0 +1,95 @@
+/*
+    This file is part of KAddressBook.
+    Copyright (C) 1999 Don Sanders <sanders@kde.org>
+
+    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.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+    As a special exception, permission is given to link this program
+    with any edition of Qt, and distribute the resulting executable,
+    without including the source code for Qt in the source distribution.
+*/
+
+#ifndef UNDO_H
+#define UNDO_H
+
+#include <qobject.h>
+#include <qptrstack.h>
+#include <qstring.h>
+
+class Command
+{
+public:
+  Command() {}
+  virtual ~Command() {};
+  virtual QString name() = 0;
+  virtual void redo() = 0; // egcs requires these methods to have
+  virtual void undo() = 0; // implementations (Seems like a bug)
+                           // pure virtual may not work
+};
+
+/** The Undo and Redo stacks now no longer inherit directly from a stack.
+* They now contain a stack internally and inherit from StackBase, which
+* has a signal for when the stack is modified. This is need to keep
+* the edit menu and toolbar up to date.
+*
+* Really this is a simple observable stack.
+*/
+class StackBase : public QObject
+{
+  Q_OBJECT
+  
+  public:
+    StackBase() : QObject() {}
+    
+    void push(Command *c);
+    bool isEmpty();
+    Command *top();
+    void clear();
+    
+  signals:
+    void changed();
+    
+  protected:
+    /** Protect the pop method so users must call undo/redo to properly
+    * use the stack, however the subclasses need it to modify the stack.
+    */
+    Command *pop();
+    
+    QPtrStack<Command> mCommandStack;
+};
+
+class UndoStack : public StackBase
+{
+public:
+  static UndoStack *instance();
+  void undo();
+
+protected:
+  UndoStack();
+  static UndoStack* instance_;
+};
+
+class RedoStack : public StackBase
+{
+public:
+  static RedoStack *instance();
+  void redo();
+
+protected:
+  RedoStack();
+  static RedoStack* instance_;
+};
+
+#endif
--
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