public static void NotifyOrThrow(this IExceptionSource ies, object source, ExceptionNotification args)
{
if (ies?.ExceptionHandler != null)
{
ies.ExceptionHandler(source, args);
}
else if (args.Severity == ExceptionSeverity.Error)
{
throw args.Exception;
}
}
public ExceptionInterceptor(IExceptionSource source, ExceptionNotificationHandler handler, bool forward)
{
_source = source;
_originalHandler = source.ExceptionHandler;
source.ExceptionHandler = nestedHandler;
_forward = forward;
void nestedHandler(object s, ExceptionNotification a)
{
handler(s, a);
if (forward)
{
_originalHandler.NotifyOrThrow(s, a);
}
}
}
/// <summary>
/// Registers an <see cref="ExceptionNotificationHandler" /> with an <see cref="IExceptionSource"/>.
/// </summary>
/// <param name="source"></param>
/// <param name="handler"></param>
/// <param name="forward">If true, also forwards the error to the original handler (if any).</param>
/// <returns>An object that, when disposed, unregisters the handler from the source.</returns>
/// <remarks>
/// <para>This function can be used directly inside a <c>using</c> block, to scope the interception
/// of exceptions by the given handler to that block.</para>
/// <para>The <paramref name="handler"/> replaces the handler already in place in the source (of any), but
/// as soon as executing leaves the block, the handler is unregistered, and the original handler restored.</para>
/// <para>If the source originally had a handler set, the <paramref name="forward"/> can be used to forward
/// the exception to the original handler, after invoking the handler passed in with <paramref name="handler"/>.</para>
/// </remarks>
/// <example>
/// <code>
/// using(source.Catch((o,a) => lastError = a))
/// {
/// var children = source.Children();
/// }
/// </code></example>
public static IDisposable Catch(this IExceptionSource source, ExceptionNotificationHandler handler, bool forward = false) =>
new ExceptionInterceptor(source, handler, forward);
