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Fix crash when abstract methods aren't implemented #196

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Merged
merged 2 commits into from
Apr 4, 2016
Merged

Fix crash when abstract methods aren't implemented #196

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56e0baa
Don't try to call abstract methods.
tonyroberts Apr 4, 2016
b04658e
Update subclass tests with events example.
tonyroberts Apr 4, 2016
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66 changes: 38 additions & 28 deletions src/runtime/classderived.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -321,37 +321,47 @@ private static void AddVirtualMethod(MethodInfo method, Type baseType, TypeBuild
ParameterInfo[] parameters = method.GetParameters();
Type[] parameterTypes = (from param in parameters select param.ParameterType).ToArray();

// create a method for calling the original method
string baseMethodName = "_" + baseType.Name + "__" + method.Name;
MethodBuilder methodBuilder = typeBuilder.DefineMethod(baseMethodName,
MethodAttributes.Public |
MethodAttributes.Final |
MethodAttributes.HideBySig,
method.ReturnType,
parameterTypes);

// emit the assembly for calling the original method using call instead of callvirt
ILGenerator il = methodBuilder.GetILGenerator();
il.Emit(OpCodes.Ldarg_0);
for (int i = 0; i < parameters.Length; ++i)
il.Emit(OpCodes.Ldarg, i + 1);
il.Emit(OpCodes.Call, method);
il.Emit(OpCodes.Ret);
// If the method isn't abstract create a method for calling the original method
string baseMethodName = null;
if (!method.IsAbstract)
{
baseMethodName = "_" + baseType.Name + "__" + method.Name;
MethodBuilder baseMethodBuilder = typeBuilder.DefineMethod(baseMethodName,
MethodAttributes.Public |
MethodAttributes.Final |
MethodAttributes.HideBySig,
method.ReturnType,
parameterTypes);

// emit the assembly for calling the original method using call instead of callvirt
ILGenerator baseIl = baseMethodBuilder.GetILGenerator();
baseIl.Emit(OpCodes.Ldarg_0);
for (int i = 0; i < parameters.Length; ++i)
baseIl.Emit(OpCodes.Ldarg, i + 1);
baseIl.Emit(OpCodes.Call, method);
baseIl.Emit(OpCodes.Ret);
}

// override the original method with a new one that dispatches to python
methodBuilder = typeBuilder.DefineMethod(method.Name,
MethodAttributes.Public |
MethodAttributes.ReuseSlot |
MethodAttributes.Virtual |
MethodAttributes.HideBySig,
method.CallingConvention,
method.ReturnType,
parameterTypes);
il = methodBuilder.GetILGenerator();
MethodBuilder methodBuilder = typeBuilder.DefineMethod(method.Name,
MethodAttributes.Public |
MethodAttributes.ReuseSlot |
MethodAttributes.Virtual |
MethodAttributes.HideBySig,
method.CallingConvention,
method.ReturnType,
parameterTypes);
ILGenerator il = methodBuilder.GetILGenerator();
il.DeclareLocal(typeof(Object[]));
il.Emit(OpCodes.Ldarg_0);
il.Emit(OpCodes.Ldstr, method.Name);
il.Emit(OpCodes.Ldstr, baseMethodName);

// don't fall back to the base type's method if it's abstract
if (null != baseMethodName)
il.Emit(OpCodes.Ldstr, baseMethodName);
else
il.Emit(OpCodes.Ldnull);

il.Emit(OpCodes.Ldc_I4, parameters.Length);
il.Emit(OpCodes.Newarr, typeof(System.Object));
il.Emit(OpCodes.Stloc_0);
Expand Down Expand Up @@ -624,7 +634,7 @@ public static T InvokeMethod<T>(IPythonDerivedType obj, string methodName, strin
}

if (origMethodName == null)
throw new NullReferenceException("Python object does not have a '" + methodName + "' method");
throw new NotImplementedException("Python object does not have a '" + methodName + "' method");

return (T)obj.GetType().InvokeMember(origMethodName,
BindingFlags.InvokeMethod,
Expand Down Expand Up @@ -683,7 +693,7 @@ public static void InvokeMethodVoid(IPythonDerivedType obj, string methodName, s
}

if (origMethodName == null)
throw new NullReferenceException("Python object does not have a '" + methodName + "' method");
throw new NotImplementedException("Python object does not have a '" + methodName + "' method");

obj.GetType().InvokeMember(origMethodName,
BindingFlags.InvokeMethod,
Expand Down
27 changes: 27 additions & 0 deletions src/testing/subclasstest.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -12,10 +12,17 @@ public interface IInterfaceTest

// test passing objects and boxing primitives
string bar(string s, int i);

// test events on interfaces
event TestEventHandler TestEvent;

void OnTestEvent(int value);
}

public class SubClassTest : IInterfaceTest
{
public event TestEventHandler TestEvent;

public SubClassTest()
{
}
Expand Down Expand Up @@ -48,6 +55,13 @@ public static IList<string> test_list(SubClassTest x)
// calls into python if return_list is overriden
return x.return_list();
}

// raise the test event
public virtual void OnTestEvent(int value)
{
if (null != TestEvent)
TestEvent(this, new TestEventArgs(value));
}
}

public class TestFunctions
Expand Down Expand Up @@ -75,5 +89,18 @@ public static IInterfaceTest pass_through(IInterfaceTest s)
{
return s;
}

public static int test_event(IInterfaceTest x, int value)
{
// reuse the event handler from eventtest.cs
EventTest et = new EventTest();
x.TestEvent += et.GenericHandler;

// raise the event (should trigger both python and managed handlers)
x.OnTestEvent(value);

x.TestEvent -= et.GenericHandler;
return et.value;
}
}
}
46 changes: 45 additions & 1 deletion src/tests/test_subclass.py
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Original file line number Diff line number Diff line change
Expand Up @@ -11,8 +11,9 @@
clr.AddReference('System')

import sys, os, string, unittest, types
from Python.Test import TestFunctions, SubClassTest, IInterfaceTest
from Python.Test import TestFunctions, SubClassTest, IInterfaceTest, TestEventArgs
from System.Collections.Generic import List
from System import NotImplementedException

# class that implements the test interface
class InterfaceTestClass(IInterfaceTest):
Expand Down Expand Up @@ -47,6 +48,26 @@ def return_list(self):
l.Add("C")
return l

# class that implements IInterfaceTest.TestEvent
class DerivedEventTest(IInterfaceTest):
__namespace__ = "Python.Test"

def __init__(self):
self.event_handlers = []

# event handling
def add_TestEvent(self, handler):
self.event_handlers.append(handler)

def remove_TestEvent(self, handler):
self.event_handlers.remove(handler)

def OnTestEvent(self, value):
args = TestEventArgs(value)
for handler in self.event_handlers:
handler(self, args)


class SubClassTests(unittest.TestCase):
"""Test subclassing managed types"""

Expand Down Expand Up @@ -109,6 +130,29 @@ def testCreateInstance(self):
y = TestFunctions.pass_through(object2)
self.assertEqual(id(y), id(object2))

def testEvents(self):

class EventHandler:
def handler(self, x, args):
self.value = args.value

event_handler = EventHandler()

x = SubClassTest()
x.TestEvent += event_handler.handler
self.assertEqual(TestFunctions.test_event(x, 1), 1)
self.assertEqual(event_handler.value, 1)

i = InterfaceTestClass()
self.assertRaises(NotImplementedException, TestFunctions.test_event, i, 2)

d = DerivedEventTest()
d.add_TestEvent(event_handler.handler)
self.assertEqual(TestFunctions.test_event(d, 3), 3)
self.assertEqual(event_handler.value, 3)
self.assertEqual(len(d.event_handlers), 1)


def test_suite():
return unittest.makeSuite(SubClassTests)

Expand Down