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// Copyright (c) 2010-2013 AlphaSierraPapa for the SharpDevelop Team
//
// 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 ICSharpCode.NRefactory.Editor
{
/// <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");
Version 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());
else
return EmptyList<TextChangeEventArgs>.Instance;
}
IEnumerable<TextChangeEventArgs> GetForwardChanges(Version other)
{
// Return changes from this(inclusive) to other(exclusive).
for (Version node = this; node != other; node = node.next) {
yield return node.change;
}
}
public int MoveOffsetTo(ITextSourceVersion other, int oldOffset, AnchorMovementType movement)
{
int offset = oldOffset;
foreach (var e in GetChangesTo(other)) {
offset = e.GetNewOffset(offset, movement);
}
return offset;
}
}
}
}
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