public static bool RaiseContractFailedEvent(
ContractFailureKind failureKind,
string userMessage,
string conditionText,
Provenance provenence,
out string resultFailureMessage)
{
bool handled = false;
string returnValue;
string displayMessage = "contract failed."; // Incomplete, but in case of OOM during resource lookup...
ContractFailedEventArgs eventArgs = null; // In case of OOM.
try
{
displayMessage = GetDisplayMessage(failureKind, userMessage, conditionText, provenence);
resultFailureMessage = displayMessage;
EventHandler <ContractFailedEventArgs> contractFailedEventLocal = ContractFailed;
if (contractFailedEventLocal != null)
{
eventArgs = new ContractFailedEventArgs(failureKind, displayMessage, conditionText);
foreach (EventHandler <ContractFailedEventArgs> handler in contractFailedEventLocal.GetInvocationList())
{
try
{
handler(null, eventArgs);
}
catch (Exception e)
{
eventArgs.ThrownDuringHandler = e;
eventArgs.SetUnwind();
}
}
if (eventArgs.Unwind)
{
// unwind
throw new ContractException(failureKind, displayMessage, userMessage, conditionText);
}
}
}
finally
{
if (eventArgs != null && eventArgs.Handled)
{
handled = true;
}
else
{
returnValue = displayMessage;
}
}
return(handled);
}
public static void ReportPreconditionFailure <TException>(string msg, string conditionTxt, Provenance provenence) where TException : Exception
#if !NETSTANDARD2_0
// Previous version are relies on new constraint for exception construction.
, new()
#endif
{
if (!RaiseContractFailedEvent(ContractFailureKind.Precondition, msg, conditionTxt, provenence, out var text))
{
string fullMessage = msg + conditionTxt;
// TODO: need to cache the factory or maybe switch to reflection-based approach.
var factory = GenerateExceptionFactory <TException>();
throw factory(fullMessage);
}
}
private static string GetFailureMessage(ContractFailureKind failureKind, string conditionText, Provenance provenence)
{
return(string.IsNullOrEmpty(conditionText)
? string.Format(CultureInfo.InvariantCulture, "{0}", failureKind.ToDisplayString())
: string.Format(CultureInfo.InvariantCulture, "{0}: {1}", failureKind.ToDisplayString(), conditionText));
}
private static string GetDisplayMessage(ContractFailureKind failureKind, string userMessage, string conditionText, Provenance provenence)
{
string message = GetFailureMessage(failureKind, conditionText, provenence);
return(string.IsNullOrEmpty(userMessage)
? string.Format(CultureInfo.InvariantCulture, "{0}.\r\n\tat {1}", message, provenence)
: string.Format(CultureInfo.InvariantCulture, "{0}: {1}.\r\n\tat {2}", message, userMessage, provenence));
}
public static void ReportFailure(ContractFailureKind kind, string msg, string conditionTxt, Provenance provenance)
{
if (!RaiseContractFailedEvent(kind, msg, conditionTxt, provenance, out var text))
{
TriggerFailure(kind, text, msg, conditionTxt);
}
}
