Merge pull request #213 from AvaloniaUI/protect-transformer-exceptions

Try/catch exceptions for override methods and events
AvaloniaUI · Feb 22, 2022 · 272a695 · 272a695
2 parents 3e307d9 + d62fa46
commit 272a695
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Showing 4 changed files with 85 additions and 39 deletions.
diff --git a/src/AvaloniaEdit.TextMate/GenericLineTransformer.cs b/src/AvaloniaEdit.TextMate/GenericLineTransformer.cs
@@ -1,3 +1,5 @@
+using System;
+
 using Avalonia.Media;
 using AvaloniaEdit.Document;
 using AvaloniaEdit.Rendering;
@@ -6,9 +8,23 @@ namespace AvaloniaEdit.TextMate
 {
     public abstract class GenericLineTransformer : DocumentColorizingTransformer
     {
+        private Action<Exception> _exceptionHandler;
+
+        public GenericLineTransformer(Action<Exception> exceptionHandler)
+        {
+            _exceptionHandler = exceptionHandler;
+        }
+
         protected override void ColorizeLine(DocumentLine line)
         {
-            TransformLine(line, CurrentContext);
+            try
+            {
+                TransformLine(line, CurrentContext);
+            }
+            catch (Exception ex)
+            {
+                _exceptionHandler?.Invoke(ex);
+            }
         }
 
         protected abstract void TransformLine(DocumentLine line, ITextRunConstructionContext context);

diff --git a/src/AvaloniaEdit.TextMate/TextMate.cs b/src/AvaloniaEdit.TextMate/TextMate.cs
@@ -108,7 +108,8 @@ TextMateColoringTransformer GetOrCreateTransformer()
 
                 if (transformer is null)
                 {
-                    transformer = new TextMateColoringTransformer(_editor.TextArea.TextView);
+                    transformer = new TextMateColoringTransformer(
+                        _editor.TextArea.TextView, _exceptionHandler);
 
                     _editor.TextArea.TextView.LineTransformers.Add(transformer);
                 }

diff --git a/src/AvaloniaEdit.TextMate/TextMateColoringTransformer.cs b/src/AvaloniaEdit.TextMate/TextMateColoringTransformer.cs
@@ -23,16 +23,22 @@ public class TextMateColoringTransformer :
         private TMModel _model;
         private TextDocument _document;
         private TextView _textView;
+        private Action<Exception> _exceptionHandler;
 
         private volatile int _firstVisibleLineIndex = -1;
         private volatile int _lastVisibleLineIndex = -1;
 
         private readonly Dictionary<int, IBrush> _brushes;
         private TextSegmentCollection<TextTransformation> _transformations;
 
-        public TextMateColoringTransformer(TextView textView)
+        public TextMateColoringTransformer(
+            TextView textView,
+            Action<Exception> exceptionHandler)
+            : base(exceptionHandler)
         {
             _textView = textView;
+            _exceptionHandler = exceptionHandler;
+
             _brushes = new Dictionary<int, IBrush>();
             _textView.VisualLinesChanged += TextView_VisualLinesChanged;
         }
@@ -51,11 +57,18 @@ public void SetModel(TextDocument document, TMModel model)
 
         private void TextView_VisualLinesChanged(object sender, EventArgs e)
         {
-            if (!_textView.VisualLinesValid || _textView.VisualLines.Count == 0)
-                return;
+            try
+            {
+                if (!_textView.VisualLinesValid || _textView.VisualLines.Count == 0)
+                    return;
 
-            _firstVisibleLineIndex = _textView.VisualLines[0].FirstDocumentLine.LineNumber - 1;
-            _lastVisibleLineIndex = _textView.VisualLines[_textView.VisualLines.Count - 1].LastDocumentLine.LineNumber - 1;
+                _firstVisibleLineIndex = _textView.VisualLines[0].FirstDocumentLine.LineNumber - 1;
+                _lastVisibleLineIndex = _textView.VisualLines[_textView.VisualLines.Count - 1].LastDocumentLine.LineNumber - 1;
+            }
+            catch (Exception ex)
+            {
+                _exceptionHandler?.Invoke(ex);
+            }
         }
 
         public void Dispose()
@@ -103,21 +116,31 @@ IBrush ForegroundTextTransformation.IColorMap.GetBrush(int colorId)
 
         protected override void TransformLine(DocumentLine line, ITextRunConstructionContext context)
         {
-            int i = line.LineNumber;
+            try
+            {
+                if (_model == null)
+                    return;
 
-            var tokens = _model.GetLineTokens(i - 1);
+                int i = line.LineNumber;
 
-            if (tokens == null)
-                return;
+                var tokens = _model.GetLineTokens(i - 1);
 
-            RemoveLineTransformations(i);
-            ProcessTokens(i, tokens);
+                if (tokens == null)
+                    return;
 
-            var transformsInLine = _transformations.FindOverlappingSegments(line);
+                RemoveLineTransformations(i);
+                ProcessTokens(i, tokens);
 
-            foreach (var transform in transformsInLine)
+                var transformsInLine = _transformations.FindOverlappingSegments(line);
+
+                foreach (var transform in transformsInLine)
+                {
+                    transform.Transform(this, line);
+                }
+            }
+            catch (Exception ex)
             {
-                transform.Transform(this, line);
+                _exceptionHandler?.Invoke(ex);
             }
         }
 
@@ -154,7 +177,7 @@ private void ProcessTokens(int lineNumber, List<TMToken> tokens)
                         fontStyle = themeRule.fontStyle;
                 }
 
-                _transformations.Add(new ForegroundTextTransformation(this, lineOffset + startIndex,
+                _transformations.Add(new ForegroundTextTransformation(this, _exceptionHandler, lineOffset + startIndex,
                     lineOffset + endIndex, foreground, background, fontStyle));
             }
         }
@@ -175,7 +198,7 @@ public void ModelTokensChanged(ModelTokensChangedEvent e)
             if (e.Ranges == null)
                 return;
 
-            if (_model.IsStopped)
+            if (_model == null || _model.IsStopped)
                 return;
 
             int firstChangedLineIndex = int.MaxValue;

diff --git a/src/AvaloniaEdit.TextMate/TextTransformation.cs b/src/AvaloniaEdit.TextMate/TextTransformation.cs
@@ -1,12 +1,9 @@
 using System;
-using System.Collections.Generic;
 
 using Avalonia.Media;
 
 using AvaloniaEdit.Document;
 
-using TextMateSharp.Model;
-
 namespace AvaloniaEdit.TextMate
 {
     public abstract class TextTransformation : TextSegment
@@ -27,50 +24,61 @@ public interface IColorMap
             IBrush GetBrush(int color);
         }
 
-        int _foreground;
-        int _background;
-        int _fontStyle;
+        private IColorMap _colorMap;
+        private Action<Exception> _exceptionHandler;
+        private int _foreground;
+        private int _background;
+        private int _fontStyle;
 
         public ForegroundTextTransformation(
             IColorMap colorMap,
+            Action<Exception> exceptionHandler,
             int startOffset,
             int endOffset,
             int foreground,
             int background,
             int fontStyle) : base(startOffset, endOffset)
         {
             _colorMap = colorMap;
+            _exceptionHandler = exceptionHandler;
             _foreground = foreground;
             _background = background;
             _fontStyle = fontStyle;
         }
 
         public override void Transform(GenericLineTransformer transformer, DocumentLine line)
         {
-            if (Length == 0)
+            try
             {
-                return;
-            }
+                if (Length == 0)
+                {
+                    return;
+                }
 
-            var formattedOffset = 0;
-            var endOffset = line.EndOffset;
+                var formattedOffset = 0;
+                var endOffset = line.EndOffset;
 
-            if (StartOffset > line.Offset)
-            {
-                formattedOffset = StartOffset - line.Offset;
-            }
+                if (StartOffset > line.Offset)
+                {
+                    formattedOffset = StartOffset - line.Offset;
+                }
 
-            if (EndOffset < line.EndOffset)
-            {
-                endOffset = EndOffset;
-            }
+                if (EndOffset < line.EndOffset)
+                {
+                    endOffset = EndOffset;
+                }
 
                 transformer.SetTextStyle(line, formattedOffset, endOffset - line.Offset - formattedOffset,
                 _colorMap.GetBrush(_foreground),
                 _colorMap.GetBrush(_background),
                 GetFontStyle(),
                 GetFontWeight(),
                 IsUnderline());
+            }
+            catch(Exception ex)
+            {
+                _exceptionHandler?.Invoke(ex);
+            }
         }
 
         FontStyle GetFontStyle()
@@ -99,7 +107,5 @@ bool IsUnderline()
 
             return false;
         }
-
-        IColorMap _colorMap;
     }
 }