Allow demystifier to add strings to existing StringBuilder (#73)

src/Ben.Demystifier/EnhancedStackTrace.Frames.cs

@@ -171,11 +171,10 @@ namespace System.Diagnostics
             // ResolveStateMachineMethod may have set declaringType to null
             if (type != null)
             {
-                var declaringTypeName = TypeNameHelper.GetTypeDisplayName(type, fullName: true, includeGenericParameterNames: true);
+                methodDisplayInfo.DeclaringType = type;
-                methodDisplayInfo.DeclaringTypeName = declaringTypeName;
             }
 
-            if (method is System.Reflection.MethodInfo mi)
+            if (method is MethodInfo mi)
             {
                 var returnParameter = mi.ReturnParameter;
                 if (returnParameter != null)
@@ -188,7 +187,6 @@ namespace System.Diagnostics
                     {
                         Prefix = "",
                         Name = "",
-                        Type = TypeNameHelper.GetTypeDisplayName(mi.ReturnType, fullName: false, includeGenericParameterNames: true).ToString(),
                         ResolvedType = mi.ReturnType,
                     };
                 }
@@ -540,7 +538,6 @@ namespace System.Diagnostics
         {
             var parameterType = parameter.ParameterType;
             var prefix = GetPrefix(parameter, parameterType);
-            var parameterTypeString = "?";
 
             if (parameterType == null)
             {
@@ -548,7 +545,6 @@ namespace System.Diagnostics
                 {
                     Prefix = prefix,
                     Name = parameter.Name,
-                    Type = parameterTypeString,
                     ResolvedType = parameterType,
                 };
             }
@@ -572,40 +568,22 @@ namespace System.Diagnostics
                 parameterType = parameterType.GetElementType();
             }
 
-            parameterTypeString = TypeNameHelper.GetTypeDisplayName(parameterType, fullName: false, includeGenericParameterNames: true);
-
             return new ResolvedParameter
             {
                 Prefix = prefix,
                 Name = parameter.Name,
-                Type = parameterTypeString,
                 ResolvedType = parameterType,
             };
         }
 
         private static ResolvedParameter GetValueTupleParameter(IList<string> tupleNames, string prefix, string name, Type parameterType)
         {
-            string typeName;
+            return new ValueTupleResolvedParameter
-
-            if (parameterType.IsValueTuple())
-            {
-                typeName = GetValueTupleParameterName(tupleNames, parameterType);
-
-            }
-            else
-            {
-                // Need to unwrap the first generic argument first.
-                var genericTypeName = TypeNameHelper.GetTypeNameForGenericType(parameterType);
-                var valueTupleFullName = GetValueTupleParameterName(tupleNames, parameterType.GetGenericArguments()[0]);
-                typeName = $"{genericTypeName}<{valueTupleFullName}>";
-            }
-
-            return new ResolvedParameter
             {
+                TupleNames = tupleNames,
                 Prefix = prefix,
                 Name = name,
-                Type = typeName,
+                ResolvedType = parameterType
-                ResolvedType = parameterType,
             };
         }
 

src/Ben.Demystifier/ExceptionExtentions.cs

@@ -4,6 +4,7 @@
 using System.Collections.Generic;
 using System.Collections.Generic.Enumerable;
 using System.Reflection;
+using System.Text;
 
 namespace System.Diagnostics
 {
@@ -12,27 +13,16 @@ namespace System.Diagnostics
     {
         private static readonly FieldInfo stackTraceString = typeof(Exception).GetField("_stackTraceString", BindingFlags.Instance | BindingFlags.NonPublic);
 
-        public static T Demystify<T>(this T exception) where T : Exception
-            => Demystify(exception, originalStacksTracker: null);
-
-        private static string GetStackTracesString(this Exception exception)
-            => (string)stackTraceString.GetValue(exception);
-
         private static void SetStackTracesString(this Exception exception, string value)
             => stackTraceString.SetValue(exception, value);
 
         /// <summary>
         /// Demystifies the given <paramref name="exception"/> and tracks the original stack traces for the whole exception tree.
         /// </summary>
-        private static T Demystify<T>(this T exception, Dictionary<Exception, string> originalStacksTracker) where T : Exception
+        public static T Demystify<T>(this T exception) where T : Exception
         {
             try
             {
-                if (originalStacksTracker?.ContainsKey(exception) == false)
-                {
-                    originalStacksTracker[exception] = exception.GetStackTracesString();
-                }
-
                 var stackTrace = new EnhancedStackTrace(exception);
 
                 if (stackTrace.FrameCount > 0)
@@ -44,11 +34,11 @@ namespace System.Diagnostics
                 {
                     foreach (var ex in EnumerableIList.Create(aggEx.InnerExceptions))
                     {
-                        ex.Demystify(originalStacksTracker);
+                        ex.Demystify();
                     }
                 }
 
-                exception.InnerException?.Demystify(originalStacksTracker);
+                exception.InnerException?.Demystify();
             }
             catch
             {
@@ -69,27 +59,6 @@ namespace System.Diagnostics
         /// </remarks>
         [Contracts.Pure]
         public static string ToStringDemystified(this Exception exception) 
-        {
+            => new StringBuilder().AppendDemystified(exception).ToString();
-            try
-            {
-                var originalStacks = new Dictionary<Exception, string>();
-                exception.Demystify(originalStacks);
-
-                var result = exception.ToString();
-
-                foreach (var kvp in originalStacks)
-                {
-                    kvp.Key.SetStackTracesString(kvp.Value);
-                }
-
-                return result;
-            }
-            catch
-            {
-                // Processing exceptions shouldn't throw exceptions; if it fails
-            }
-
-            return exception.ToString();
-        }
     }
 }

src/Ben.Demystifier/ResolvedMethod.cs

@@ -11,7 +11,7 @@ namespace System.Diagnostics
     {
         public MethodBase MethodBase { get; set; }
 
-        public string DeclaringTypeName { get; set; }
+        public Type DeclaringType { get; set; }
         
         public bool IsAsync { get; set; }
 
@@ -39,11 +39,9 @@ namespace System.Diagnostics
 
         internal StringBuilder Append(StringBuilder builder)
         {
-
             if (IsAsync)
             {
-                builder
+                builder.Append("async ");
-                    .Append("async ");
             }
 
             if (ReturnParameter != null)
@@ -52,7 +50,7 @@ namespace System.Diagnostics
                 builder.Append(" ");
             }
 
-            if (!string.IsNullOrEmpty(DeclaringTypeName))
+            if (DeclaringType != null)
             {
 
                 if (Name == ".ctor")
@@ -60,17 +58,16 @@ namespace System.Diagnostics
                     if (string.IsNullOrEmpty(SubMethod) && !IsLambda)
                         builder.Append("new ");
 
-                    builder.Append(DeclaringTypeName);
+                    AppendDeclaringTypeName(builder);
                 }
                 else if (Name == ".cctor")
                 {
                     builder.Append("static ");
-                    builder.Append(DeclaringTypeName);
+                    AppendDeclaringTypeName(builder);
                 }
                 else
                 {
-                    builder
+                    AppendDeclaringTypeName(builder)
-                        .Append(DeclaringTypeName)
                         .Append(".")
                         .Append(Name);
                 }
@@ -145,5 +142,10 @@ namespace System.Diagnostics
 
             return builder;
         }
+
+        private StringBuilder AppendDeclaringTypeName(StringBuilder builder)
+        {
+            return DeclaringType != null ? builder.AppendTypeDisplayName(DeclaringType, fullName: true, includeGenericParameterNames: true) : builder;
+        }
     }
 }

src/Ben.Demystifier/ResolvedParameter.cs

@@ -9,8 +9,6 @@ namespace System.Diagnostics
     {
         public string Name { get; set; }
 
-        public string Type { get; set; }
-
         public Type ResolvedType { get; set; }
 
         public string Prefix { get; set; }
@@ -25,7 +23,15 @@ namespace System.Diagnostics
                   .Append(" ");
             }
 
-            sb.Append(Type);
+            if (ResolvedType != null)
+            {
+                AppendTypeName(sb);
+            }
+            else
+            {
+                sb.Append("?");
+            }
+
             if (!string.IsNullOrEmpty(Name))
             {
                 sb.Append(" ")
@@ -34,5 +40,10 @@ namespace System.Diagnostics
 
             return sb;
         }
+
+        protected virtual void AppendTypeName(StringBuilder sb) 
+        {
+            sb.AppendTypeDisplayName(ResolvedType, fullName: false, includeGenericParameterNames: true);
+        }
     }
 }

src/Ben.Demystifier/StringBuilderExtentions.cs

@@ -0,0 +1,49 @@
+// Copyright (c) Ben A Adams. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic.Enumerable;
+using System.Text;
+
+namespace System.Diagnostics 
+{
+    public static class StringBuilderExtentions
+    {
+        public static StringBuilder AppendDemystified(this StringBuilder builder, Exception exception)
+        {
+            try
+            {
+                var stackTrace = new EnhancedStackTrace(exception);
+
+                if (stackTrace.FrameCount > 0)
+                {
+                    stackTrace.Append(builder);
+                }
+
+                if (exception is AggregateException aggEx)
+                {
+                    foreach (var ex in EnumerableIList.Create(aggEx.InnerExceptions))
+                    {
+                        builder.AppendInnerException(ex);
+                    }
+                }
+
+                if (exception.InnerException != null)
+                {
+                    builder.AppendInnerException(exception.InnerException);
+                }
+            }
+            catch
+            {
+                // Processing exceptions shouldn't throw exceptions; if it fails
+            }
+
+            return builder;
+        }
+
+        private static void AppendInnerException(this StringBuilder builder, Exception exception) 
+            => builder.Append(" ---> ")
+                .AppendDemystified(exception)
+                .AppendLine()
+                .Append("   --- End of inner exception stack trace ---");
+    }
+}

src/Ben.Demystifier/TypeNameHelper.cs

@@ -7,7 +7,7 @@ using System.Text;
 namespace System.Diagnostics
 {
     // Adapted from https://github.com/aspnet/Common/blob/dev/shared/Microsoft.Extensions.TypeNameHelper.Sources/TypeNameHelper.cs
-    public class TypeNameHelper
+    public static class TypeNameHelper
     {
         public static readonly Dictionary<Type, string> BuiltInTypeNames = new Dictionary<Type, string>
         {
@@ -43,6 +43,12 @@ namespace System.Diagnostics
             return builder.ToString();
         }
 
+        public static StringBuilder AppendTypeDisplayName(this StringBuilder builder, Type type, bool fullName = true, bool includeGenericParameterNames = false)
+        {
+            ProcessType(builder, type, new DisplayNameOptions(fullName, includeGenericParameterNames));
+            return builder;
+        }
+
         /// <summary>
         /// Returns a name of given generic type without '`'.
         /// </summary>

src/Ben.Demystifier/ValueTupleResolvedParameter.cs

@@ -0,0 +1,62 @@
+// Copyright (c) Ben A Adams. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.Diagnostics.Internal;
+using System.Text;
+
+namespace System.Diagnostics 
+{
+    public class ValueTupleResolvedParameter : ResolvedParameter
+    {
+        public IList<string> TupleNames { get; set; }
+
+        protected override void AppendTypeName(StringBuilder sb)
+        {
+            if (ResolvedType.IsValueTuple())
+            {
+                AppendValueTupleParameterName(sb, ResolvedType);
+            }
+            else
+            {
+                // Need to unwrap the first generic argument first.
+                sb.Append(TypeNameHelper.GetTypeNameForGenericType(ResolvedType));
+                sb.Append("<");
+                AppendValueTupleParameterName(sb, ResolvedType.GetGenericArguments()[0]);
+                sb.Append(">");
+            }
+        }
+
+
+        private void AppendValueTupleParameterName(StringBuilder sb, Type parameterType)
+        {
+            sb.Append("(");
+            var args = parameterType.GetGenericArguments();
+            for (var i = 0; i < args.Length; i++)
+            {
+                if (i > 0)
+                {
+                    sb.Append(", ");
+                }
+
+                sb.AppendTypeDisplayName(args[i], fullName: false, includeGenericParameterNames: true);
+
+                if (i >= TupleNames.Count)
+                {
+                    continue;
+                }
+
+                var argName = TupleNames[i];
+                if (argName == null)
+                {
+                    continue;
+                }
+
+                sb.Append(" ");
+                sb.Append(argName);
+            }
+
+            sb.Append(")");
+        }
+    }
+}