/// <summary>
/// When called after SetError, sets the cause of the error.
/// </summary>
/// <param name="cause">The cause of the current error</param>
public static void SetCause(Exception cause)
{
var currentException = PythonException.FetchCurrentRaw();
currentException.Normalize();
using var causeInstance = Converter.ToPythonReference(cause);
Runtime.PyException_SetCause(currentException.Value !.Reference, causeInstance.Steal());
currentException.Restore();
}
/// <summary>
/// SetError Method
/// </summary>
/// <remarks>
/// Sets the current Python exception given a CLR exception
/// object. The CLR exception instance is wrapped as a Python
/// object, allowing it to be handled naturally from Python.
/// </remarks>
public static bool SetError(Exception e)
{
Debug.Assert(e is not null);
// Because delegates allow arbitrary nesting of Python calling
// managed calling Python calling... etc. it is possible that we
// might get a managed exception raised that is a wrapper for a
// Python exception. In that case we'd rather have the real thing.
var pe = e as PythonException;
if (pe != null)
{
pe.Restore();
return(true);
}
using var instance = Converter.ToPythonReference(e);
if (instance.IsNull())
{
return(false);
}
var exceptionInfo = ExceptionDispatchInfo.Capture(e);
using var pyInfo = Converter.ToPythonReference(exceptionInfo);
if (Runtime.PyObject_SetAttrString(instance, DispatchInfoAttribute, pyInfo) != 0)
{
return(false);
}
Debug.Assert(Runtime.PyObject_TypeCheck(instance, new BorrowedReference(BaseException)));
var type = Runtime.PyObject_TYPE(instance);
Runtime.PyErr_SetObject(type, instance);
return(true);
}
private object TrueDispatch(object[] args)
{
MethodInfo method = dtype.GetMethod("Invoke");
ParameterInfo[] pi = method.GetParameters();
Type rtype = method.ReturnType;
NewReference op;
using (var pyargs = NewReference.DangerousFromPointer(Runtime.PyTuple_New(pi.Length)))
{
for (var i = 0; i < pi.Length; i++)
{
// Here we own the reference to the Python value, and we
// give the ownership to the arg tuple.
var arg = Converter.ToPythonReference(args[i], pi[i].ParameterType);
if (arg.IsNull())
{
throw PythonException.ThrowLastAsClrException();
}
int res = Runtime.PyTuple_SetItem(pyargs, i, arg.Steal());
if (res != 0)
{
throw PythonException.ThrowLastAsClrException();
}
}
op = Runtime.PyObject_Call(target.Reference, pyargs, BorrowedReference.Null);
}
if (op.IsNull())
{
throw PythonException.ThrowLastAsClrException();
}
using (op)
{
int byRefCount = pi.Count(parameterInfo => parameterInfo.ParameterType.IsByRef);
if (byRefCount > 0)
{
// By symmetry with MethodBinder.Invoke, when there are out
// parameters we expect to receive a tuple containing
// the result, if any, followed by the out parameters. If there is only
// one out parameter and the return type of the method is void,
// we instead receive the out parameter as the result from Python.
bool isVoid = rtype == typeof(void);
int tupleSize = byRefCount + (isVoid ? 0 : 1);
if (isVoid && byRefCount == 1)
{
// The return type is void and there is a single out parameter.
for (int i = 0; i < pi.Length; i++)
{
Type t = pi[i].ParameterType;
if (t.IsByRef)
{
if (!Converter.ToManaged(op, t, out object newArg, true))
{
Exceptions.RaiseTypeError($"The Python function did not return {t.GetElementType()} (the out parameter type)");
throw PythonException.ThrowLastAsClrException();
}
args[i] = newArg;
break;
}
}
return(null);
}
else if (Runtime.PyTuple_Check(op) && Runtime.PyTuple_Size(op) == tupleSize)
{
int index = isVoid ? 0 : 1;
for (int i = 0; i < pi.Length; i++)
{
Type t = pi[i].ParameterType;
if (t.IsByRef)
{
BorrowedReference item = Runtime.PyTuple_GetItem(op, index++);
if (!Converter.ToManaged(item, t, out object newArg, true))
{
Exceptions.RaiseTypeError($"The Python function returned a tuple where element {i} was not {t.GetElementType()} (the out parameter type)");
throw PythonException.ThrowLastAsClrException();
}
args[i] = newArg;
}
}
if (isVoid)
{
return(null);
}
BorrowedReference item0 = Runtime.PyTuple_GetItem(op, 0);
if (!Converter.ToManaged(item0, rtype, out object result0, true))
{
Exceptions.RaiseTypeError($"The Python function returned a tuple where element 0 was not {rtype} (the return type)");
throw PythonException.ThrowLastAsClrException();
}
return(result0);
}
else
{
string tpName = Runtime.PyObject_GetTypeName(op);
if (Runtime.PyTuple_Check(op))
{
tpName += $" of size {Runtime.PyTuple_Size(op)}";
}
StringBuilder sb = new StringBuilder();
if (!isVoid)
{
sb.Append(rtype.FullName);
}
for (int i = 0; i < pi.Length; i++)
{
Type t = pi[i].ParameterType;
if (t.IsByRef)
{
if (sb.Length > 0)
{
sb.Append(",");
}
sb.Append(t.GetElementType().FullName);
}
}
string returnValueString = isVoid ? "" : "the return value and ";
Exceptions.RaiseTypeError($"Expected a tuple ({sb}) of {returnValueString}the values for out and ref parameters, got {tpName}.");
throw PythonException.ThrowLastAsClrException();
}
}
if (rtype == typeof(void))
{
return(null);
}
object result;
if (!Converter.ToManaged(op, rtype, out result, true))
{
throw PythonException.ThrowLastAsClrException();
}
return(result);
}
}