File: InheritanceMargin\InheritanceGlyphManager.cs
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Project: src\src\VisualStudio\Core\Def\Microsoft.VisualStudio.LanguageServices_hjmslwj1_wpftmp.csproj (Microsoft.VisualStudio.LanguageServices)
// 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.
 
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Linq;
using System.Windows.Controls;
using System.Windows.Media;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.Editor.Host;
using Microsoft.CodeAnalysis.Editor.Shared.Extensions;
using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
using Microsoft.CodeAnalysis.Shared.Collections;
using Microsoft.CodeAnalysis.Shared.TestHooks;
using Microsoft.VisualStudio.LanguageServices.Implementation.InheritanceMargin.MarginGlyph;
using Microsoft.VisualStudio.PlatformUI;
using Microsoft.VisualStudio.Text;
using Microsoft.VisualStudio.Text.Classification;
using Microsoft.VisualStudio.Text.Editor;
using Microsoft.VisualStudio.Text.Formatting;
using Microsoft.VisualStudio.Utilities;
 
namespace Microsoft.VisualStudio.LanguageServices.Implementation.InheritanceMargin;
 
/// <summary>
/// Manager controls all the glyphs of Inheritance Margin in <see cref="InheritanceMarginViewMargin"/>.
/// </summary>
internal sealed partial class InheritanceGlyphManager : IDisposable
{
    // We want to our glyphs to have the same background color as the glyphs in GlyphMargin.
    private const string GlyphMarginName = "Indicator Margin";
 
    private readonly Workspace _workspace;
    private readonly double _heightAndWidthOfTheGlyph;
    private readonly IWpfTextView _textView;
    private readonly IThreadingContext _threadingContext;
    private readonly IStreamingFindUsagesPresenter _streamingFindUsagesPresenter;
    private readonly ClassificationTypeMap _classificationTypeMap;
    private readonly IClassificationFormatMap _classificationFormatMap;
    private readonly IUIThreadOperationExecutor _operationExecutor;
    private readonly IEditorFormatMap _editorFormatMap;
    private readonly IAsynchronousOperationListener _listener;
    private readonly Canvas _glyphsContainer;
 
    /// <summary>
    /// Mutable.  Must only be accessed from the UI thread.
    /// </summary>
    private SimpleMutableIntervalTree<GlyphData, GlyphDataIntrospector> _glyphDataTree;
 
    public InheritanceGlyphManager(
        Workspace workspace,
        IWpfTextView textView,
        IThreadingContext threadingContext,
        IStreamingFindUsagesPresenter streamingFindUsagesPresenter,
        IClassificationFormatMap classificationFormatMap,
        ClassificationTypeMap classificationTypeMap,
        IUIThreadOperationExecutor operationExecutor,
        IEditorFormatMap editorFormatMap,
        IAsynchronousOperationListener listener,
        Canvas canvas,
        double heightAndWidthOfTheGlyph)
    {
        _workspace = workspace;
        _textView = textView;
        _threadingContext = threadingContext;
        _streamingFindUsagesPresenter = streamingFindUsagesPresenter;
        _classificationTypeMap = classificationTypeMap;
        _classificationFormatMap = classificationFormatMap;
        _operationExecutor = operationExecutor;
        _editorFormatMap = editorFormatMap;
        _glyphsContainer = canvas;
        _listener = listener;
        _heightAndWidthOfTheGlyph = heightAndWidthOfTheGlyph;
        _editorFormatMap.FormatMappingChanged += FormatMappingChanged;
 
        _glyphDataTree = new(new GlyphDataIntrospector(), values: null);
        UpdateBackgroundColor();
    }
 
    void IDisposable.Dispose()
    {
        _editorFormatMap.FormatMappingChanged -= FormatMappingChanged;
    }
 
    /// <summary>
    /// Generate the glyph by the given <paramref name="tag"/>, and add it to the margin.
    /// It should only be called by UI thread because UI elements are manipulated by this method.
    /// </summary>
    public void AddGlyph(InheritanceMarginTag tag, SnapshotSpan span)
    {
        _threadingContext.ThrowIfNotOnUIThread();
        var lines = _textView.TextViewLines;
        if (lines.IntersectsBufferSpan(span) && GetStartingLine(lines, span) is IWpfTextViewLine line)
        {
            var glyph = CreateNewGlyph(tag);
            SetTop(line, glyph);
            _glyphDataTree.AddIntervalInPlace(new GlyphData(span, glyph));
            _glyphsContainer.Children.Add(glyph);
        }
    }
 
    /// <summary>
    /// Remove the glyphs covered by <paramref name="snapshotSpan"/>.
    /// It should only be called by UI thread because UI elements are manipulated by this method.
    /// </summary>
    public void RemoveGlyphs(SnapshotSpan snapshotSpan)
    {
        _threadingContext.ThrowIfNotOnUIThread();
        var glyphDataToRemove = _glyphDataTree.GetIntervalsThatIntersectWith(snapshotSpan.Start, snapshotSpan.Length);
        foreach (var (_, glyph) in glyphDataToRemove)
        {
            _glyphsContainer.Children.Remove(glyph);
        }
 
        var remainingGlyphData = _glyphDataTree.Except(glyphDataToRemove).ToImmutableArray();
        _glyphDataTree = new(new GlyphDataIntrospector(), values: null);
        foreach (var glyphData in remainingGlyphData)
        {
            _glyphDataTree.AddIntervalInPlace(glyphData);
        }
    }
 
    /// <summary>
    /// Remove the glyphs that are no long visible or covered by the <paramref name="newOrReformattedLines"/>.
    /// Refresh all the other the existing glyphs with the <paramref name="snapshot"/>.
    /// It should only be called by UI thread because UI elements are manipulated by this method.
    /// </summary>
    public void SetSnapshotAndUpdate(ITextSnapshot snapshot, IList<ITextViewLine> newOrReformattedLines, IList<ITextViewLine> translatedLines)
    {
        _threadingContext.ThrowIfNotOnUIThread();
        if (!_glyphDataTree.IsEmpty())
        {
            // Go through all the existing visuals and invalidate or transform as appropriate.
            var allGlyphData = _glyphDataTree.ToImmutableArray();
            _glyphDataTree = new(new GlyphDataIntrospector(), values: null);
            foreach (var (span, glyph) in allGlyphData)
            {
                var newSpan = span.TranslateTo(snapshot, SpanTrackingMode.EdgeInclusive);
                if (!_textView.TextViewLines.IntersectsBufferSpan(newSpan) || GetStartingLine(newOrReformattedLines, newSpan) != null)
                {
                    //Either visual is no longer visible or it crosses a line
                    //that was reformatted.
                    _glyphsContainer.Children.Remove(glyph);
                }
                else
                {
                    _glyphDataTree.AddIntervalInPlace(new GlyphData(newSpan, glyph));
                    var line = GetStartingLine(translatedLines, newSpan);
                    if (line != null)
                    {
                        SetTop(line, glyph);
                    }
                }
            }
        }
    }
 
    private void SetTop(ITextViewLine line, InheritanceMarginGlyph glyph)
        => Canvas.SetTop(glyph, line.TextTop - _textView.ViewportTop);
 
    private static ITextViewLine? GetStartingLine(IList<ITextViewLine> lines, Span span)
    {
        if (lines.Count > 0)
        {
            var index = lines.ToImmutableArray().BinarySearch(span.Start, CompareWithLineStartAndEnd);
            if (index >= 0)
            {
                return lines[index];
            }
 
            var lastLine = lines[^1];
            if (lastLine.EndIncludingLineBreak == lastLine.Snapshot.Length && span.Start == lastLine.EndIncludingLineBreak)
            {
                // As a special case, if the last line ends at the end of the buffer and the span starts at the end of the buffer
                // as well, treat is as crossing the last line in the buffer.
                return lastLine;
            }
        }
 
        return null;
    }
 
    private static int CompareWithLineStartAndEnd(ITextViewLine line, int value)
    {
        if (value < line.Start)
        {
            return 1;
        }
 
        // EndIncludingLineBreak usually equals the start of next line (the exclusion is if this is the last line, which will be handled separately),
        // and we always prefer to use the line start, so still return -1 when value == line.EndIncludingLineBreak.
        if (value >= line.EndIncludingLineBreak)
        {
            return -1;
        }
 
        return 0;
    }
 
    private InheritanceMarginGlyph CreateNewGlyph(InheritanceMarginTag tag)
        => new(
            _workspace,
            _threadingContext,
            _streamingFindUsagesPresenter,
            _classificationTypeMap,
            _classificationFormatMap,
            _operationExecutor,
            tag,
            _textView,
            _listener)
        { Height = _heightAndWidthOfTheGlyph, Width = _heightAndWidthOfTheGlyph };
 
    private void FormatMappingChanged(object sender, FormatItemsEventArgs e)
        => UpdateBackgroundColor();
 
    private void UpdateBackgroundColor()
    {
        _threadingContext.ThrowIfNotOnUIThread();
        var resourceDictionary = _editorFormatMap.GetProperties(GlyphMarginName);
        if (resourceDictionary.Contains(EditorFormatDefinition.BackgroundColorId))
        {
            var backgroundColor = (Color)resourceDictionary[EditorFormatDefinition.BackgroundColorId];
            // Set background color for all the glyphs
            ImageThemingUtilities.SetImageBackgroundColor(_glyphsContainer, backgroundColor);
        }
    }
}