UndoStack.cs


0:	// UndoStack.cs
1:	// Copyright (c) 2000 Mike Krueger
2:	//
3:	// This program is free software; you can redistribute it and/or modify
4:	// it under the terms of the GNU General Public License as published by
5:	// the Free Software Foundation; either version 2 of the License, or
6:	// (at your option) any later version.
7:	//
8:	// This program is distributed in the hope that it will be useful,
9:	// but WITHOUT ANY WARRANTY; without even the implied warranty of
10:	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11:	// GNU General Public License for more details.
12:	//
13:	// You should have received a copy of the GNU General Public License
14:	// along with this program; if not, write to the Free Software
15:	// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
16:
17:	using System;
18:	using System.Diagnostics;
19:	using System.Collections;
20:	using SharpDevelop.Internal.Text;
21:
22:	namespace SharpDevelop.Internal.Undo {
23:
24:	/// <summary>
25:	/// This class implements an undo stack
26:	/// </summary>
27:	public class UndoStack
28:	{
29:	Stack undostack = new Stack();
30:	Stack redostack = new Stack();
31:
32:	public event EventHandler AfterUndo;
33:	public event EventHandler AfterRedo;
34:
35:	/// <summary>
36:	/// This property is EXCLUSIVELY for the UndoQueue class, don't USE it
37:	/// </summary>
38:	internal Stack _UndoStack {
39:	get {
40:	return undostack;
41:	}
42:	}
43:
44:	/// <summary>
45:	/// You call this method to pool the last x operations from the undo stack
46:	/// to make 1 operation from it.
47:	/// </summary>
48:	public void UndoLast(int x)
49:	{
50:	undostack.Push(new UndoQueue(this, x));
51:	}
52:
53:	/// <summary>
54:	/// Call this method to undo the last operation on the stack
55:	/// </summary>
56:	public void Undo()
57:	{
58:	if (undostack.Count > 0) {
59:	IUndoableOperation uedit = (IUndoableOperation)undostack.Pop();
60:	redostack.Push(uedit);
61:	uedit.Undo();
62:	if (AfterUndo != null)
63:	AfterUndo(null, null);
64:	}
65:	}
66:
67:	/// <summary>
68:	/// Call this method to redo the last undone operation
69:	/// </summary>
70:	public void Redo()
71:	{
72:	if (redostack.Count > 0) {
73:	IUndoableOperation uedit = (IUndoableOperation)redostack.Pop();
74:	undostack.Push(uedit);
75:	uedit.Redo();
76:	if (AfterRedo != null)
77:	AfterRedo(null, null);
78:	}
79:	}
80:
81:	/// <summary>
82:	/// Call this method to push an UndoableOperation on the undostack, the redostack
83:	/// will be cleared, if you use this method.
84:	/// </summary>
85:	public void Push(IUndoableOperation operation)
86:	{
87:	if (operation == null)
88:	throw new ArgumentNullException("UndoStack.Push(UndoableOperation operation) : operation can't be null");
89:
90:	undostack.Push(operation);
91:	ClearRedoStack();
92:	}
93:
94:	/// <summary>
95:	/// Call this method, if you want to clear the redo stack
96:	/// </summary>
97:	public void ClearRedoStack()
98:	{
99:	redostack.Clear();
100:	}
101:	}
102:	}