Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / Tools / System.Activities.Presentation / System / Activities / Presentation / UndoEngine.cs / 1305376 / UndoEngine.cs
//----------------------------------------------------------------
// Copyright (c) Microsoft Corporation. All rights reserved.
//---------------------------------------------------------------
namespace System.Activities.Presentation
{
using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq;
using System.Runtime;
[Fx.Tag.XamlVisible(false)]
public class UndoEngine : IUndoEngineOperations
{
const int capacity = 100;
List undoBuffer;
List redoBuffer;
EditingContext context;
Bookmark bookmark;
//interface which contains actual implementation of AddUndoUnit, Undo and Redo operations
IUndoEngineOperations undoEngineImpl = null;
public event EventHandler UndoUnitAdded;
public event EventHandler UndoUnitDiscarded;
internal event EventHandler ExecuteUndo;
public event EventHandler UndoRedoBufferChanged;
public UndoEngine(EditingContext context)
{
this.context = context;
undoBuffer = new List(capacity);
redoBuffer = new List(capacity);
this.undoEngineImpl = this;
}
//CreateBookmark - creates a new UndoUnit which gatters all edits in its
//undo unit list. all changes in bookmark appear as a one change and can be
//undoned or redoned as a one set.
internal Bookmark CreateBookmark(string bookmarkName)
{
//only one bookmark is supported
if (null == this.bookmark)
{
//create bookmark undo unit, and give it a description
BookmarkUndoUnit unit = new BookmarkUndoUnit(this.context)
{
Description = bookmarkName ?? string.Format(CultureInfo.InvariantCulture, "Bookmark {0}", Guid.NewGuid()),
};
//create bookmark, and pass bookmark undo unit to it.
this.bookmark = new Bookmark(this, unit);
//switch implementation of AddUndoUnit, Undo, Redo to be delegated through bookmark
this.undoEngineImpl = bookmark;
return this.bookmark;
}
throw FxTrace.Exception.AsError(new NotSupportedException(SR.UndoEngine_NestedBookmarksException));
}
public IEnumerable GetUndoActions()
{
return this.undoBuffer.Select(p => p.Description);
}
public IEnumerable GetRedoActions()
{
return this.redoBuffer.Select(p => p.Description);
}
void NotifyChange()
{
if (null != this.UndoRedoBufferChanged)
{
this.UndoRedoBufferChanged(this, EventArgs.Empty);
}
}
public void AddUndoUnit(UndoUnit unit)
{
if (unit == null)
{
throw FxTrace.Exception.ArgumentNull("unit");
}
this.undoEngineImpl.AddUndoUnitCore(unit);
this.NotifyChange();
}
public bool Undo()
{
this.IsUndoRedoInProgress = true;
bool succeeded = this.undoEngineImpl.UndoCore();
this.IsUndoRedoInProgress = false;
if (succeeded)
{
this.NotifyChange();
}
return succeeded;
}
public bool Redo()
{
this.IsUndoRedoInProgress = true;
bool succeeded = this.undoEngineImpl.RedoCore();
this.IsUndoRedoInProgress = false;
if (succeeded)
{
this.NotifyChange();
}
return succeeded;
}
public bool IsUndoRedoInProgress
{
get;
private set;
}
void IUndoEngineOperations.AddUndoUnitCore(UndoUnit unit)
{
undoBuffer.Add(unit);
RaiseUndoUnitAdded(unit);
if (undoBuffer.Count > capacity)
{
undoBuffer.RemoveAt(0);
RaiseUndoUnitDiscarded();
}
redoBuffer.Clear();
}
bool IUndoEngineOperations.UndoCore()
{
bool succeeded = false;
if (undoBuffer.Count > 0)
{
UndoUnit unitToUndo = undoBuffer.Last();
undoBuffer.RemoveAt(undoBuffer.Count - 1);
unitToUndo.Undo();
redoBuffer.Add(unitToUndo);
RaiseExecuteUndo(unitToUndo);
succeeded = true;
}
return succeeded;
}
bool IUndoEngineOperations.RedoCore()
{
bool succeeded = false;
if (redoBuffer.Count > 0)
{
UndoUnit unitToRedo = redoBuffer.Last();
redoBuffer.RemoveAt(redoBuffer.Count - 1);
unitToRedo.Redo();
undoBuffer.Add(unitToRedo);
succeeded = true;
}
return succeeded;
}
void RaiseUndoUnitAdded(UndoUnit unit)
{
if (this.UndoUnitAdded != null)
{
this.UndoUnitAdded(this, new UndoUnitEventArgs() { UndoUnit = unit });
}
}
void RaiseUndoUnitDiscarded()
{
if (this.UndoUnitDiscarded != null)
{
this.UndoUnitDiscarded(this, null);
}
}
void RaiseExecuteUndo(UndoUnit unitToUndo)
{
if (this.ExecuteUndo != null)
{
this.ExecuteUndo(this, new UndoUnitEventArgs() { UndoUnit = unitToUndo });
}
}
//Bookmark implmeentation - implements core UndoEngine operations + IDisposable -
//default bookmark behaviour is to Rollback changes, unless commited explicitly.
//usage of IDisposable enables usage of pattern:
// using (Bookmark b = new Bookmark())....
internal sealed class Bookmark : IDisposable, IUndoEngineOperations
{
BookmarkUndoUnit containerUndoUnit;
UndoEngine undoEngine;
bool isCommited = false;
bool isRolledBack = false;
bool isDisposed = false;
internal Bookmark(UndoEngine undoEngine, BookmarkUndoUnit undoUnit)
{
this.undoEngine = undoEngine;
this.containerUndoUnit = undoUnit;
}
public void CommitBookmark()
{
//cannot commit more than once...
if (this.isDisposed)
{
throw FxTrace.Exception.AsError(new InvalidOperationException(string.Format(CultureInfo.CurrentUICulture, SR.UndoEngine_OperationNotAllowed, "CommitBookmark")));
}
this.isCommited = true;
//restore original undo engine implementation
this.undoEngine.undoEngineImpl = this.undoEngine;
//get rid of the bookmark
this.undoEngine.bookmark = null;
//check if bookmark has any changes
if (this.containerUndoUnit.DoList.Count != 0 || this.containerUndoUnit.RedoList.Count != 0)
{
//add all changes in bookmark into a undo list as a one element
this.undoEngine.AddUndoUnit(this.containerUndoUnit);
}
//dispose bookmark
this.Dispose();
}
public void RollbackBookmark()
{
//cannot rollback more than once
if (this.isDisposed)
{
throw FxTrace.Exception.AsError(new InvalidOperationException(string.Format(CultureInfo.CurrentUICulture, SR.UndoEngine_OperationNotAllowed, "RollbackBookmark")));
}
this.isRolledBack = true;
//get through the list of all accumulated changes and reverse each of them
foreach (UndoUnit unit in this.containerUndoUnit.DoList.Reverse())
{
unit.Undo();
}
//clear the lists
this.containerUndoUnit.DoList.Clear();
this.containerUndoUnit.RedoList.Clear();
//restore original undo engine implementation
this.undoEngine.undoEngineImpl = this.undoEngine;
//get rid of the bookmark
this.undoEngine.bookmark = null;
//dispose bookmark
this.Dispose();
}
public void Dispose()
{
if (!this.isDisposed)
{
GC.SuppressFinalize(this);
DisposeInternal();
}
}
void DisposeInternal()
{
if (!this.isDisposed)
{
//if not commited or rolled back - rollback by default
if (!this.isCommited && !this.isRolledBack)
{
this.RollbackBookmark();
}
this.isDisposed = true;
}
}
void IUndoEngineOperations.AddUndoUnitCore(UndoUnit unit)
{
//add element to Undo list
this.containerUndoUnit.DoList.Add(unit);
//clear redo list
this.containerUndoUnit.RedoList.Clear();
}
bool IUndoEngineOperations.UndoCore()
{
//if there is anything to undo
bool succeeded = false;
if (this.containerUndoUnit.DoList.Count > 0)
{
//get the last element done
UndoUnit unitToUndo = this.containerUndoUnit.DoList.Last();
//remove it
this.containerUndoUnit.DoList.RemoveAt(this.containerUndoUnit.DoList.Count - 1);
//undo it
unitToUndo.Undo();
//and insert to the head of redo list
this.containerUndoUnit.RedoList.Insert(0, unitToUndo);
succeeded = true;
}
return succeeded;
}
bool IUndoEngineOperations.RedoCore()
{
//if there is anything to redo
bool succeeded = false;
if (this.containerUndoUnit.RedoList.Count > 0)
{
//get first element to redo
UndoUnit unitToRedo = this.containerUndoUnit.RedoList.First();
//remove it
this.containerUndoUnit.RedoList.RemoveAt(0);
//redo it
unitToRedo.Redo();
//add it to the end of undo list
this.containerUndoUnit.DoList.Add(unitToRedo);
succeeded = true;
}
return succeeded;
}
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
//----------------------------------------------------------------
// Copyright (c) Microsoft Corporation. All rights reserved.
//---------------------------------------------------------------
namespace System.Activities.Presentation
{
using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.Linq;
using System.Runtime;
[Fx.Tag.XamlVisible(false)]
public class UndoEngine : IUndoEngineOperations
{
const int capacity = 100;
List undoBuffer;
List redoBuffer;
EditingContext context;
Bookmark bookmark;
//interface which contains actual implementation of AddUndoUnit, Undo and Redo operations
IUndoEngineOperations undoEngineImpl = null;
public event EventHandler UndoUnitAdded;
public event EventHandler UndoUnitDiscarded;
internal event EventHandler ExecuteUndo;
public event EventHandler UndoRedoBufferChanged;
public UndoEngine(EditingContext context)
{
this.context = context;
undoBuffer = new List(capacity);
redoBuffer = new List(capacity);
this.undoEngineImpl = this;
}
//CreateBookmark - creates a new UndoUnit which gatters all edits in its
//undo unit list. all changes in bookmark appear as a one change and can be
//undoned or redoned as a one set.
internal Bookmark CreateBookmark(string bookmarkName)
{
//only one bookmark is supported
if (null == this.bookmark)
{
//create bookmark undo unit, and give it a description
BookmarkUndoUnit unit = new BookmarkUndoUnit(this.context)
{
Description = bookmarkName ?? string.Format(CultureInfo.InvariantCulture, "Bookmark {0}", Guid.NewGuid()),
};
//create bookmark, and pass bookmark undo unit to it.
this.bookmark = new Bookmark(this, unit);
//switch implementation of AddUndoUnit, Undo, Redo to be delegated through bookmark
this.undoEngineImpl = bookmark;
return this.bookmark;
}
throw FxTrace.Exception.AsError(new NotSupportedException(SR.UndoEngine_NestedBookmarksException));
}
public IEnumerable GetUndoActions()
{
return this.undoBuffer.Select(p => p.Description);
}
public IEnumerable GetRedoActions()
{
return this.redoBuffer.Select(p => p.Description);
}
void NotifyChange()
{
if (null != this.UndoRedoBufferChanged)
{
this.UndoRedoBufferChanged(this, EventArgs.Empty);
}
}
public void AddUndoUnit(UndoUnit unit)
{
if (unit == null)
{
throw FxTrace.Exception.ArgumentNull("unit");
}
this.undoEngineImpl.AddUndoUnitCore(unit);
this.NotifyChange();
}
public bool Undo()
{
this.IsUndoRedoInProgress = true;
bool succeeded = this.undoEngineImpl.UndoCore();
this.IsUndoRedoInProgress = false;
if (succeeded)
{
this.NotifyChange();
}
return succeeded;
}
public bool Redo()
{
this.IsUndoRedoInProgress = true;
bool succeeded = this.undoEngineImpl.RedoCore();
this.IsUndoRedoInProgress = false;
if (succeeded)
{
this.NotifyChange();
}
return succeeded;
}
public bool IsUndoRedoInProgress
{
get;
private set;
}
void IUndoEngineOperations.AddUndoUnitCore(UndoUnit unit)
{
undoBuffer.Add(unit);
RaiseUndoUnitAdded(unit);
if (undoBuffer.Count > capacity)
{
undoBuffer.RemoveAt(0);
RaiseUndoUnitDiscarded();
}
redoBuffer.Clear();
}
bool IUndoEngineOperations.UndoCore()
{
bool succeeded = false;
if (undoBuffer.Count > 0)
{
UndoUnit unitToUndo = undoBuffer.Last();
undoBuffer.RemoveAt(undoBuffer.Count - 1);
unitToUndo.Undo();
redoBuffer.Add(unitToUndo);
RaiseExecuteUndo(unitToUndo);
succeeded = true;
}
return succeeded;
}
bool IUndoEngineOperations.RedoCore()
{
bool succeeded = false;
if (redoBuffer.Count > 0)
{
UndoUnit unitToRedo = redoBuffer.Last();
redoBuffer.RemoveAt(redoBuffer.Count - 1);
unitToRedo.Redo();
undoBuffer.Add(unitToRedo);
succeeded = true;
}
return succeeded;
}
void RaiseUndoUnitAdded(UndoUnit unit)
{
if (this.UndoUnitAdded != null)
{
this.UndoUnitAdded(this, new UndoUnitEventArgs() { UndoUnit = unit });
}
}
void RaiseUndoUnitDiscarded()
{
if (this.UndoUnitDiscarded != null)
{
this.UndoUnitDiscarded(this, null);
}
}
void RaiseExecuteUndo(UndoUnit unitToUndo)
{
if (this.ExecuteUndo != null)
{
this.ExecuteUndo(this, new UndoUnitEventArgs() { UndoUnit = unitToUndo });
}
}
//Bookmark implmeentation - implements core UndoEngine operations + IDisposable -
//default bookmark behaviour is to Rollback changes, unless commited explicitly.
//usage of IDisposable enables usage of pattern:
// using (Bookmark b = new Bookmark())....
internal sealed class Bookmark : IDisposable, IUndoEngineOperations
{
BookmarkUndoUnit containerUndoUnit;
UndoEngine undoEngine;
bool isCommited = false;
bool isRolledBack = false;
bool isDisposed = false;
internal Bookmark(UndoEngine undoEngine, BookmarkUndoUnit undoUnit)
{
this.undoEngine = undoEngine;
this.containerUndoUnit = undoUnit;
}
public void CommitBookmark()
{
//cannot commit more than once...
if (this.isDisposed)
{
throw FxTrace.Exception.AsError(new InvalidOperationException(string.Format(CultureInfo.CurrentUICulture, SR.UndoEngine_OperationNotAllowed, "CommitBookmark")));
}
this.isCommited = true;
//restore original undo engine implementation
this.undoEngine.undoEngineImpl = this.undoEngine;
//get rid of the bookmark
this.undoEngine.bookmark = null;
//check if bookmark has any changes
if (this.containerUndoUnit.DoList.Count != 0 || this.containerUndoUnit.RedoList.Count != 0)
{
//add all changes in bookmark into a undo list as a one element
this.undoEngine.AddUndoUnit(this.containerUndoUnit);
}
//dispose bookmark
this.Dispose();
}
public void RollbackBookmark()
{
//cannot rollback more than once
if (this.isDisposed)
{
throw FxTrace.Exception.AsError(new InvalidOperationException(string.Format(CultureInfo.CurrentUICulture, SR.UndoEngine_OperationNotAllowed, "RollbackBookmark")));
}
this.isRolledBack = true;
//get through the list of all accumulated changes and reverse each of them
foreach (UndoUnit unit in this.containerUndoUnit.DoList.Reverse())
{
unit.Undo();
}
//clear the lists
this.containerUndoUnit.DoList.Clear();
this.containerUndoUnit.RedoList.Clear();
//restore original undo engine implementation
this.undoEngine.undoEngineImpl = this.undoEngine;
//get rid of the bookmark
this.undoEngine.bookmark = null;
//dispose bookmark
this.Dispose();
}
public void Dispose()
{
if (!this.isDisposed)
{
GC.SuppressFinalize(this);
DisposeInternal();
}
}
void DisposeInternal()
{
if (!this.isDisposed)
{
//if not commited or rolled back - rollback by default
if (!this.isCommited && !this.isRolledBack)
{
this.RollbackBookmark();
}
this.isDisposed = true;
}
}
void IUndoEngineOperations.AddUndoUnitCore(UndoUnit unit)
{
//add element to Undo list
this.containerUndoUnit.DoList.Add(unit);
//clear redo list
this.containerUndoUnit.RedoList.Clear();
}
bool IUndoEngineOperations.UndoCore()
{
//if there is anything to undo
bool succeeded = false;
if (this.containerUndoUnit.DoList.Count > 0)
{
//get the last element done
UndoUnit unitToUndo = this.containerUndoUnit.DoList.Last();
//remove it
this.containerUndoUnit.DoList.RemoveAt(this.containerUndoUnit.DoList.Count - 1);
//undo it
unitToUndo.Undo();
//and insert to the head of redo list
this.containerUndoUnit.RedoList.Insert(0, unitToUndo);
succeeded = true;
}
return succeeded;
}
bool IUndoEngineOperations.RedoCore()
{
//if there is anything to redo
bool succeeded = false;
if (this.containerUndoUnit.RedoList.Count > 0)
{
//get first element to redo
UndoUnit unitToRedo = this.containerUndoUnit.RedoList.First();
//remove it
this.containerUndoUnit.RedoList.RemoveAt(0);
//redo it
unitToRedo.Redo();
//add it to the end of undo list
this.containerUndoUnit.DoList.Add(unitToRedo);
succeeded = true;
}
return succeeded;
}
}
}
}
// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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