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//
// TextSourceVersionProvider.cs
//
// Taken from NRefactory 5.
//
// Author:
// Mike Krüger <mkrueger@xamarin.com>
//
// Copyright (c) 2014 Xamarin Inc. (http://xamarin.com)
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
using System;
using System.Collections.Generic;
using System.Linq;
namespace MonoDevelop.Core.Text
{
/// <summary>
/// Provides ITextSourceVersion instances.
/// </summary>
public class TextSourceVersionProvider
{
Version currentVersion;
public TextSourceVersionProvider ()
{
this.currentVersion = new Version (this);
}
/// <summary>
/// Gets the current version.
/// </summary>
public ITextSourceVersion CurrentVersion {
get { return currentVersion; }
}
/// <summary>
/// Replaces the current version with a new version.
/// </summary>
/// <param name="change">Change from current version to new version</param>
public void AppendChange (TextChangeEventArgs change)
{
if (change == null)
throw new ArgumentNullException ("change");
currentVersion.change = change;
currentVersion.next = new Version (currentVersion);
currentVersion = currentVersion.next;
}
sealed class Version : ITextSourceVersion
{
// Reference back to the provider.
// Used to determine if two checkpoints belong to the same document.
readonly TextSourceVersionProvider provider;
// ID used for CompareAge()
readonly int id;
// the change from this version to the next version
internal TextChangeEventArgs change;
internal Version next;
internal Version (TextSourceVersionProvider provider)
{
this.provider = provider;
}
internal Version (Version prev)
{
this.provider = prev.provider;
this.id = unchecked(prev.id + 1);
}
public bool BelongsToSameDocumentAs (ITextSourceVersion other)
{
Version o = other as Version;
return o != null && provider == o.provider;
}
public int CompareAge (ITextSourceVersion other)
{
if (other == null)
throw new ArgumentNullException ("other");
var o = other as Version;
if (o == null || provider != o.provider)
throw new ArgumentException ("Versions do not belong to the same document.");
// We will allow overflows, but assume that the maximum distance between checkpoints is 2^31-1.
// This is guaranteed on x86 because so many checkpoints don't fit into memory.
return Math.Sign (unchecked(this.id - o.id));
}
public IEnumerable<TextChangeEventArgs> GetChangesTo (ITextSourceVersion other)
{
int result = CompareAge (other);
Version o = (Version)other;
if (result < 0)
return GetForwardChanges (o);
else if (result > 0)
return o.GetForwardChanges (this).Reverse ().Select (change => change.Invert ());
return Enumerable.Empty<TextChangeEventArgs> ();
}
IEnumerable<TextChangeEventArgs> GetForwardChanges (Version other)
{
for (Version node = this; node != other; node = node.next) {
yield return node.change;
}
}
public int MoveOffsetTo (ITextSourceVersion other, int oldOffset)
{
int offset = oldOffset;
foreach (var e in GetChangesTo(other)) {
offset = e.GetNewOffset (offset);
}
return offset;
}
}
}
}
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