Fix ForegroundTextTransformation objects mem leak

src/AvaloniaEdit.TextMate/TextMateColoringTransformer.cs

@@ -17,8 +17,7 @@ namespace AvaloniaEdit.TextMate
 {
     public class TextMateColoringTransformer :
         GenericLineTransformer,
-        IModelTokensChangedListener,
-        ForegroundTextTransformation.IColorMap
+        IModelTokensChangedListener
     {
         private Theme _theme;
         private IGrammar _grammar;
@@ -77,6 +76,7 @@ private void TextView_VisualLinesChanged(object sender, EventArgs e)
         public void Dispose()
         {
             _textView.VisualLinesChanged -= TextView_VisualLinesChanged;
+            _brushes.Clear();
         }
 
         public void SetTheme(Theme theme)
@@ -105,15 +105,6 @@ public void SetGrammar(IGrammar grammar)
             }
         }
 
-        IBrush ForegroundTextTransformation.IColorMap.GetBrush(int colorId)
-        {
-            if (_brushes == null)
-                return null;
-
-            _brushes.TryGetValue(colorId, out IBrush result);
-            return result;
-        }
-
         protected override void TransformLine(DocumentLine line, ITextRunConstructionContext context)
         {
             try
@@ -190,7 +181,7 @@ private void GetLineTransformations(int lineNumber, List<TMToken> tokens, Foregr
                 if (transformations[i] == null)
                     transformations[i] = new ForegroundTextTransformation();
 
-                transformations[i].ColorMap = this;
+                transformations[i].ColorMap = _brushes;
                 transformations[i].ExceptionHandler = _exceptionHandler;
                 transformations[i].StartOffset = lineOffset + startIndex;
                 transformations[i].EndOffset = lineOffset + endIndex;

src/AvaloniaEdit.TextMate/TextTransformation.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 
 using AvaloniaEdit.Document;
 
@@ -13,12 +14,7 @@ public abstract class TextTransformation : TextSegment
 
     public class ForegroundTextTransformation : TextTransformation
     {
-        public interface IColorMap
-        {
-            AM.IBrush GetBrush(int color);
-        }
-
-        public IColorMap ColorMap { get; set; }
+        public Dictionary<int, AM.IBrush> ColorMap { get; set; }
         public Action<Exception> ExceptionHandler { get; set; }
         public int ForegroundColor { get; set; }
         public int BackgroundColor { get; set; }
@@ -47,13 +43,13 @@ public override void Transform(GenericLineTransformer transformer, DocumentLine
                 }
 
                 transformer.SetTextStyle(line, formattedOffset, endOffset - line.Offset - formattedOffset,
-                ColorMap.GetBrush(ForegroundColor),
-                ColorMap.GetBrush(BackgroundColor),
-                GetFontStyle(),
-                GetFontWeight(),
-                IsUnderline());
+                    GetBrush(ForegroundColor),
+                    GetBrush(BackgroundColor),
+                    GetFontStyle(),
+                    GetFontWeight(),
+                    IsUnderline());
             }
-            catch(Exception ex)
+            catch (Exception ex)
             {
                 ExceptionHandler?.Invoke(ex);
             }
@@ -85,5 +81,14 @@ bool IsUnderline()
 
             return false;
         }
+
+        AM.IBrush GetBrush(int colorId)
+        {
+            if (ColorMap == null)
+                return null;
+
+            ColorMap.TryGetValue(colorId, out AM.IBrush result);
+            return result;
+        }
     }
 }