Add support for rendering exceptions

src/Spectre.Console/Internal/ExceptionFormatter.cs

@@ -0,0 +1,159 @@
+using System;
+using System.Linq;
+using System.Text;
+using Spectre.Console.Internal;
+using Spectre.Console.Rendering;
+
+namespace Spectre.Console
+{
+    internal static class ExceptionFormatter
+    {
+        private static readonly Color _typeColor = Color.White;
+        private static readonly Color _methodColor = Color.Yellow;
+        private static readonly Color _parameterColor = Color.Blue;
+        private static readonly Color _pathColor = Color.Yellow;
+        private static readonly Color _dimmedColor = Color.Grey;
+
+        public static IRenderable Format(Exception exception, ExceptionFormats format)
+        {
+            if (exception is null)
+            {
+                throw new ArgumentNullException(nameof(exception));
+            }
+
+            var info = ExceptionParser.Parse(exception.ToString());
+            if (info == null)
+            {
+                return new Text(exception.ToString());
+            }
+
+            return GetException(info, format);
+        }
+
+        private static IRenderable GetException(ExceptionInfo info, ExceptionFormats format)
+        {
+            if (info is null)
+            {
+                throw new ArgumentNullException(nameof(info));
+            }
+
+            return new Rows(new IRenderable[]
+            {
+                GetMessage(info, format),
+                GetStackFrames(info, format),
+            }).Expand();
+        }
+
+        private static Markup GetMessage(ExceptionInfo ex, ExceptionFormats format)
+        {
+            var shortenTypes = (format & ExceptionFormats.ShortenTypes) != 0;
+            var type = Emphasize(ex.Type, new[] { '.' }, _typeColor.ToMarkupString(), shortenTypes);
+            var message = $"[b red]{ex.Message.SafeMarkup()}[/]";
+            return new Markup(string.Concat(type, ": ", message));
+        }
+
+        private static Grid GetStackFrames(ExceptionInfo ex, ExceptionFormats format)
+        {
+            var grid = new Grid();
+            grid.AddColumn(new GridColumn().PadLeft(2).PadRight(0).NoWrap());
+            grid.AddColumn(new GridColumn().PadLeft(1).PadRight(0));
+
+            // Inner
+            if (ex.Inner != null)
+            {
+                grid.AddRow(
+                    Text.Empty,
+                    GetException(ex.Inner, format));
+            }
+
+            // Stack frames
+            foreach (var frame in ex.Frames)
+            {
+                var builder = new StringBuilder();
+
+                // Method
+                var shortenMethods = (format & ExceptionFormats.ShortenMethods) != 0;
+                builder.Append(Emphasize(frame.Method, new[] { '.' }, _methodColor.ToMarkupString(), shortenMethods));
+                builder.Append('(');
+                builder.Append(string.Join(", ", frame.Parameters.Select(x => $"[{_parameterColor.ToMarkupString()}]{x.Type.SafeMarkup()}[/] {x.Name}")));
+                builder.Append(')');
+
+                if (frame.Path != null)
+                {
+                    builder.Append(" [").Append(_dimmedColor.ToMarkupString()).Append("]in[/] ");
+
+                    // Path
+                    AppendPath(builder, frame, format);
+
+                    // Line number
+                    if (frame.LineNumber != null)
+                    {
+                        builder.Append(':');
+                        builder.Append('[').Append(_parameterColor.ToMarkupString()).Append(']').Append(frame.LineNumber).Append("[/]");
+                    }
+                }
+
+                grid.AddRow($"[{_dimmedColor.ToMarkupString()}]at[/]", builder.ToString());
+            }
+
+            return grid;
+        }
+
+        private static void AppendPath(StringBuilder builder, StackFrameInfo frame, ExceptionFormats format)
+        {
+            if (frame?.Path is null)
+            {
+                return;
+            }
+
+            void RenderLink()
+            {
+                var shortenPaths = (format & ExceptionFormats.ShortenPaths) != 0;
+                builder.Append(Emphasize(frame.Path, new[] { '/', '\\' }, $"b {_pathColor.ToMarkupString()}", shortenPaths));
+            }
+
+            if ((format & ExceptionFormats.ShowLinks) != 0)
+            {
+                var hasLink = frame.TryGetUri(out var uri);
+                if (hasLink && uri != null)
+                {
+                    builder.Append("[link=").Append(uri.AbsoluteUri).Append(']');
+                }
+
+                RenderLink();
+
+                if (hasLink && uri != null)
+                {
+                    builder.Append("[/]");
+                }
+            }
+            else
+            {
+                RenderLink();
+            }
+        }
+
+        private static string Emphasize(string input, char[] separators, string color, bool compact)
+        {
+            var builder = new StringBuilder();
+
+            var type = input;
+            var index = type.LastIndexOfAny(separators);
+            if (index != -1)
+            {
+                if (!compact)
+                {
+                    builder.Append("[silver]").Append(type, 0, index + 1).Append("[/]");
+                }
+
+                builder.Append('[').Append(color).Append(']').Append(type, index + 1, type.Length - index - 1).Append("[/]");
+            }
+            else
+            {
+                builder.Append(type);
+            }
+
+            return builder.ToString();
+        }
+    }
+}