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//
// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License. See License.txt in the project root for license information.
//
// This file contain implementations details that are subject to change without notice.
// Use at your own risk.
//
using System;
using System.Collections.Generic;
using System.Globalization;
using System.ComponentModel.Composition;
using System.ComponentModel;
namespace Microsoft.VisualStudio.Text.Operations.Standalone
{
[Export(typeof(ITextUndoHistoryRegistry))]
[Export(typeof(UndoHistoryRegistryImpl))]
internal class UndoHistoryRegistryImpl : ITextUndoHistoryRegistry
{
#region Private Fields
internal Dictionary<ITextUndoHistory, int> histories;
private Dictionary<WeakReferenceForDictionaryKey, ITextUndoHistory> weakContextMapping;
private Dictionary<object, ITextUndoHistory> strongContextMapping;
#endregion // Private Fields
public UndoHistoryRegistryImpl()
{
// set up the list of histories
histories = new Dictionary<ITextUndoHistory, int>();
// set up the mappings from contexts to histories
weakContextMapping = new Dictionary<WeakReferenceForDictionaryKey, ITextUndoHistory>();
strongContextMapping = new Dictionary<object, ITextUndoHistory>();
}
/// <summary>
///
/// </summary>
public IEnumerable<ITextUndoHistory> Histories
{
get { return histories.Keys; }
}
/// <summary>
///
/// </summary>
/// <param name="context"></param>
/// <returns></returns>
public ITextUndoHistory RegisterHistory(object context)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
return RegisterHistory(context, false);
}
/// <summary>
///
/// </summary>
/// <param name="context"></param>
/// <param name="keepAlive"></param>
/// <returns></returns>
public ITextUndoHistory RegisterHistory(object context, bool keepAlive)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
ITextUndoHistory result;
if (strongContextMapping.ContainsKey(context))
{
result = strongContextMapping[context];
if (!keepAlive)
{
strongContextMapping.Remove(context);
weakContextMapping.Add(new WeakReferenceForDictionaryKey(context), result);
}
}
else if (weakContextMapping.ContainsKey(new WeakReferenceForDictionaryKey(context)))
{
result = weakContextMapping[new WeakReferenceForDictionaryKey(context)];
if (keepAlive)
{
weakContextMapping.Remove(new WeakReferenceForDictionaryKey(context));
strongContextMapping.Add(context, result);
}
}
else
{
result = new UndoHistoryImpl(this);
histories.Add(result, 1);
if (keepAlive)
{
strongContextMapping.Add(context, result);
}
else
{
weakContextMapping.Add(new WeakReferenceForDictionaryKey(context), result);
}
}
return result;
}
/// <summary>
///
/// </summary>
/// <param name="context"></param>
/// <returns></returns>
public ITextUndoHistory GetHistory(object context)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
ITextUndoHistory result;
if (strongContextMapping.ContainsKey(context))
{
result = strongContextMapping[context];
}
else if (weakContextMapping.ContainsKey(new WeakReferenceForDictionaryKey(context)))
{
result = weakContextMapping[new WeakReferenceForDictionaryKey(context)];
}
else
{
throw new InvalidOperationException("Strings.GetHistoryCannotFindContextInRegistry");
}
return result;
}
/// <summary>
///
/// </summary>
/// <param name="context"></param>
/// <param name="history"></param>
/// <returns></returns>
public bool TryGetHistory(object context, out ITextUndoHistory history)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
ITextUndoHistory result = null;
if (strongContextMapping.ContainsKey(context))
{
result = strongContextMapping[context];
}
else if (weakContextMapping.ContainsKey(new WeakReferenceForDictionaryKey(context)))
{
result = weakContextMapping[new WeakReferenceForDictionaryKey(context)];
}
history = result;
return (result != null);
}
/// <summary>
///
/// </summary>
/// <param name="context"></param>
/// <param name="history"></param>
public void AttachHistory(object context, ITextUndoHistory history)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (history == null)
{
throw new ArgumentNullException(nameof(history));
}
AttachHistory(context, history, false);
}
/// <summary>
///
/// </summary>
/// <param name="context"></param>
/// <param name="history"></param>
/// <param name="keepAlive"></param>
public void AttachHistory(object context, ITextUndoHistory history, bool keepAlive)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
if (history == null)
{
throw new ArgumentNullException(nameof(history));
}
if (strongContextMapping.ContainsKey(context) || weakContextMapping.ContainsKey(new WeakReferenceForDictionaryKey(context)))
{
throw new InvalidOperationException("Strings.AttachHistoryAlreadyContainsContextInRegistry");
}
if (!histories.ContainsKey(history))
{
histories.Add(history, 1);
}
else
{
++histories[history];
}
if (keepAlive)
{
strongContextMapping.Add(context, history);
}
else
{
weakContextMapping.Add(new WeakReferenceForDictionaryKey(context), history);
}
}
/// <summary>
///
/// </summary>
/// <param name="history"></param>
public void RemoveHistory(ITextUndoHistory history)
{
if (history == null)
{
throw new ArgumentNullException(nameof(history));
}
if (!histories.ContainsKey(history))
{
return;
}
histories.Remove(history);
List<object> strongToRemove = new List<object>();
foreach (object o in strongContextMapping.Keys)
{
if (Object.ReferenceEquals(strongContextMapping[o], history))
{
strongToRemove.Add(o);
}
}
strongToRemove.ForEach(delegate(object o) { strongContextMapping.Remove(o); });
List<WeakReferenceForDictionaryKey> weakToRemove = new List<WeakReferenceForDictionaryKey>();
foreach (WeakReferenceForDictionaryKey o in weakContextMapping.Keys)
{
if (Object.ReferenceEquals(weakContextMapping[o], history))
{
weakToRemove.Add(o);
}
}
weakToRemove.ForEach(delegate(WeakReferenceForDictionaryKey o) { weakContextMapping.Remove(o); });
return;
}
}
}
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