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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
#nullable disable
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.Editor;
using Microsoft.CodeAnalysis.Editor.Shared.Extensions;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Microsoft.CodeAnalysis.Text;
using Microsoft.CodeAnalysis.Text.Shared.Extensions;
using Microsoft.VisualStudio.ComponentModelHost;
using Microsoft.VisualStudio.Language.Intellisense;
using Microsoft.VisualStudio.LanguageServices.Implementation.Extensions;
using Microsoft.VisualStudio.LanguageServices.Implementation.ProjectSystem;
using Microsoft.VisualStudio.Shell.Interop;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Differencing;
using Roslyn.Utilities;
namespace Microsoft.VisualStudio.LanguageServices.Implementation.Preview
{
internal class FileChange : AbstractChange
{
private readonly TextDocument _left;
private readonly TextDocument _right;
private readonly IComponentModel _componentModel;
public readonly DocumentId Id;
private readonly ITextBuffer _buffer;
private readonly Encoding _encoding;
private readonly IVsImageService2 _imageService;
public FileChange(TextDocument left,
TextDocument right,
IComponentModel componentModel,
AbstractChange parent,
PreviewEngine engine,
IVsImageService2 imageService) : base(engine)
{
Contract.ThrowIfFalse(left != null || right != null);
this.Id = left != null ? left.Id : right.Id;
_left = left;
_right = right;
_imageService = imageService;
_componentModel = componentModel;
var bufferFactory = componentModel.GetService<ITextBufferFactoryService>();
var bufferText = left != null
? left.GetTextSynchronously(CancellationToken.None)
: right.GetTextSynchronously(CancellationToken.None);
_buffer = bufferFactory.CreateTextBuffer(bufferText.ToString(), bufferFactory.InertContentType);
_encoding = bufferText.Encoding;
this.Children = ComputeChildren(left, right, CancellationToken.None);
this.parent = parent;
}
private ChangeList ComputeChildren(TextDocument left, TextDocument right, CancellationToken cancellationToken)
{
if (left == null)
{
// Added document.
return GetEntireDocumentAsSpanChange(right);
}
else if (right == null)
{
// Removed document.
return GetEntireDocumentAsSpanChange(left);
}
var oldText = left.GetTextSynchronously(cancellationToken);
var newText = right.GetTextSynchronously(cancellationToken);
var diffSelector = _componentModel.GetService<ITextDifferencingSelectorService>();
var diffService = diffSelector.GetTextDifferencingService(
left.Project.Services.GetService<IContentTypeLanguageService>().GetDefaultContentType());
diffService ??= diffSelector.DefaultTextDifferencingService;
var diff = ComputeDiffSpans(diffService, left, right, cancellationToken);
if (diff.Differences.Count == 0)
{
// There are no changes.
return ChangeList.Empty;
}
return GetChangeList(diff, right.Id, oldText, newText);
}
private ChangeList GetChangeList(IHierarchicalDifferenceCollection diff, DocumentId id, SourceText oldText, SourceText newText)
{
var spanChanges = new List<SpanChange>();
foreach (var difference in diff)
{
var leftSpan = diff.LeftDecomposition.GetSpanInOriginal(difference.Left);
var rightSpan = diff.RightDecomposition.GetSpanInOriginal(difference.Right);
var leftText = oldText.GetSubText(leftSpan.ToTextSpan()).ToString();
var rightText = newText.GetSubText(rightSpan.ToTextSpan()).ToString();
var trackingSpan = _buffer.CurrentSnapshot.CreateTrackingSpan(leftSpan, SpanTrackingMode.EdgeInclusive);
var isDeletion = difference.DifferenceType == DifferenceType.Remove;
var displayText = isDeletion ? GetDisplayText(leftText) : GetDisplayText(rightText);
var spanChange = new SpanChange(trackingSpan, _buffer, id, displayText, leftText, rightText, isDeletion, this, engine);
spanChanges.Add(spanChange);
}
return new ChangeList(spanChanges.ToArray());
}
private ChangeList GetEntireDocumentAsSpanChange(TextDocument document)
{
// Show the whole document.
var entireSpan = _buffer.CurrentSnapshot.CreateTrackingSpan(0, _buffer.CurrentSnapshot.Length, SpanTrackingMode.EdgeInclusive);
var text = document.GetTextAsync().Result.ToString();
var displayText = GetDisplayText(text);
var entireSpanChild = new SpanChange(entireSpan, _buffer, document.Id, displayText, text, text, isDeletion: false, parent: this, engine: engine);
return new ChangeList(new[] { entireSpanChild });
}
private static string GetDisplayText(string excerpt)
{
if (excerpt.Contains("\r\n"))
{
var split = excerpt.Split(new[] { "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
if (split.Length > 1)
{
return string.Format("{0} ... {1}", split[0].Trim(), split[split.Length - 1].Trim());
}
}
return excerpt.Trim();
}
public override int GetText(out VSTREETEXTOPTIONS tto, out string pbstrText)
{
if (_left == null)
{
pbstrText = ServicesVSResources.bracket_plus_bracket + _right.Name;
}
else if (_right == null)
{
pbstrText = ServicesVSResources.bracket_bracket + _left.Name;
}
else
{
pbstrText = _right.Name;
}
tto = VSTREETEXTOPTIONS.TTO_DEFAULT;
return VSConstants.S_OK;
}
public override int GetTipText(out VSTREETOOLTIPTYPE eTipType, out string pbstrText)
{
eTipType = VSTREETOOLTIPTYPE.TIPTYPE_DEFAULT;
pbstrText = null;
return VSConstants.E_FAIL;
}
public override int OnRequestSource(object pIUnknownTextView)
{
if (pIUnknownTextView != null && Children.Changes != null && Children.Changes.Length > 0)
{
engine.SetTextView(pIUnknownTextView);
UpdatePreview();
}
return VSConstants.S_OK;
}
public override void UpdatePreview()
=> engine.UpdatePreview(this.Id, (SpanChange)Children.Changes[0]);
private SourceText UpdateBufferText()
{
foreach (SpanChange child in Children.Changes)
{
using var edit = _buffer.CreateEdit();
edit.Replace(child.GetSpan(), child.GetApplicableText());
edit.ApplyAndLogExceptions();
}
return SourceText.From(_buffer.CurrentSnapshot.GetText(), _encoding);
}
public TextDocument GetOldDocument()
=> _left;
public TextDocument GetUpdatedDocument()
{
if (_left == null || _right == null)
{
// Added or removed document.
return _right;
}
return _right.WithText(UpdateBufferText());
}
// Note that either _left or _right *must* be non-null (we are either adding, removing or changing a file).
public TextDocumentKind ChangedDocumentKind => (_left ?? _right).Kind;
internal override void GetDisplayData(VSTREEDISPLAYDATA[] pData)
{
var document = _right ?? _left;
// If these are documents from a VS workspace, then attempt to get the right display
// data from the underlying VSHierarchy and itemids for the document.
var workspace = document.Project.Solution.Workspace;
if (workspace is VisualStudioWorkspaceImpl vsWorkspace)
{
if (vsWorkspace.TryGetImageListAndIndex(_imageService, document.Id, out pData[0].hImageList, out pData[0].Image))
{
pData[0].SelectedImage = pData[0].Image;
return;
}
}
pData[0].Image = pData[0].SelectedImage
= document.Project.Language == LanguageNames.CSharp ? (ushort)StandardGlyphGroup.GlyphCSharpFile :
(ushort)StandardGlyphGroup.GlyphGroupClass;
}
private static IHierarchicalDifferenceCollection ComputeDiffSpans(ITextDifferencingService diffService, TextDocument left, TextDocument right, CancellationToken cancellationToken)
{
// TODO: it would be nice to have a syntax based differ for presentation here,
// current way of just using text differ has its own issue, and using syntax differ in compiler that are for incremental parser
// has its own drawbacks.
var oldText = left.GetTextSynchronously(cancellationToken);
var newText = right.GetTextSynchronously(cancellationToken);
var oldString = oldText.ToString();
var newString = newText.ToString();
return diffService.DiffStrings(oldString, newString, new StringDifferenceOptions()
{
DifferenceType = StringDifferenceTypes.Line,
});
}
}
}
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