DTLib.Demystifier/src/Ben.Demystifier/ExceptionExtentions.cs
Alexander Sher fbd6ea49ab Allow demystifier to add strings to existing StringBuilder (second attempt) (#80)
* Allow demystifier to add strings to existing StringBuilder

* Add exception message
2019-02-10 20:50:33 +00:00

65 lines
2.4 KiB
C#

// 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.Collections.Generic.Enumerable;
using System.Reflection;
using System.Text;
namespace System.Diagnostics
{
/// <nodoc />
public static class ExceptionExtentions
{
private static readonly FieldInfo stackTraceString = typeof(Exception).GetField("_stackTraceString", BindingFlags.Instance | BindingFlags.NonPublic);
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>
public static T Demystify<T>(this T exception) where T : Exception
{
try
{
var stackTrace = new EnhancedStackTrace(exception);
if (stackTrace.FrameCount > 0)
{
exception.SetStackTracesString(stackTrace.ToString());
}
if (exception is AggregateException aggEx)
{
foreach (var ex in EnumerableIList.Create(aggEx.InnerExceptions))
{
ex.Demystify();
}
}
exception.InnerException?.Demystify();
}
catch
{
// Processing exceptions shouldn't throw exceptions; if it fails
}
return exception;
}
/// <summary>
/// Gets demystified string representation of the <paramref name="exception"/>.
/// </summary>
/// <remarks>
/// <see cref="Demystify{T}"/> method mutates the exception instance that can cause
/// issues if a system relies on the stack trace be in the specific form.
/// Unlike <see cref="Demystify{T}"/> this method is pure. It calls <see cref="Demystify{T}"/> first,
/// computes a demystified string representation and then restores the original state of the exception back.
/// </remarks>
[Contracts.Pure]
public static string ToStringDemystified(this Exception exception)
=> new StringBuilder().AppendDemystified(exception).ToString();
}
}