/// <summary>
/// Trace traces a function which returns an object with the given span. If the object is a task, the span will be finished when the task completes.
/// </summary>
/// <param name="span">The span to use for tracing. The scope for the span should not be set to finish on close.</param>
/// <param name="func">The function to trace</param>
/// <param name="onComplete">an optional function to call when the function/task completes. By default exceptions will be added to the span and the span will be finished.</param>
/// <returns>The result of the function call</returns>
public static object Trace(this Span span, Func <object> func, Action <Exception> onComplete = null)
{
onComplete = onComplete ?? new Action <Exception>(e =>
{
if (e != null)
{
span.SetException(e);
}
span.Finish();
});
try
{
var result = func();
if (result is Task task)
{
var typ = task.GetType();
var genericArgs = GetGenericTypeArguments(typeof(Task <>), typ);
if (genericArgs.Length == 1)
{
if (!_traceTaskMethods.TryGetValue(genericArgs[0], out var traceTask))
{
traceTask = DynamicMethodBuilder <Func <Span, Task, Action <Exception>, Task> > .CreateMethodCallDelegate(typeof(Extensions), "TraceTask", methodGenericArguments : genericArgs);
_traceTaskMethods[genericArgs[0]] = traceTask;
}
result = traceTask(span, task, onComplete);
}
else
{
result = TraceTask(span, task, onComplete);
}
}
else
{
onComplete(null);
}
return(result);
}
catch (Exception e)
{
onComplete(e);
throw;
}
}
/// <summary>
/// Tries to call an instance method with the specified name, a single parameter, and a return value.
/// </summary>
/// <typeparam name="TArg1">The type of the method's single parameter.</typeparam>
/// <typeparam name="TResult">The type of the method's result value.</typeparam>
/// <param name="source">The object to call the method on.</param>
/// <param name="methodName">The name of the method to call.</param>
/// <param name="arg1">The value to pass as the method's single argument.</param>
/// <param name="value">The value returned by the method.</param>
/// <returns><c>true</c> if the method was found, <c>false</c> otherwise.</returns>
public static bool TryCallMethod <TArg1, TResult>(this object source, string methodName, TArg1 arg1, out TResult value)
{
var type = source.GetType();
var paramType1 = typeof(TArg1);
object cachedItem = Cache.GetOrAdd(
$"{type.AssemblyQualifiedName}.{methodName}.{paramType1.AssemblyQualifiedName}",
key =>
DynamicMethodBuilder <Func <object, TArg1, TResult> >
.CreateMethodCallDelegate(
type,
methodName,
methodParameterTypes: new[] { paramType1 }));
if (cachedItem is Func <object, TArg1, TResult> func)
{
value = func(source, arg1);
return(true);
}
value = default;
return(false);
}