protected Type CreateProxyType(Type type)
{
if (type.GetConstructor(new Type[0]) == null)
{
throw new PatchProxyTypeException($"Type {type} doesn't have an empty constructor.");
}
RuntimeTypeBuilder proxyBuilder = new RuntimeTypeBuilder($"{{Guid.NewGuid()}}.{type.FullName}Patch", type);
FieldBuilder modified = proxyBuilder.DefineField("_modified", typeof(HashSet <string>), FieldAttributes.Private);
var modifiedField = Field(proxyBuilder.This, modified);
foreach (PropertyInfo propInfo in type.GetRuntimeProperties())
{
if (propInfo.CanRead && propInfo.CanWrite && propInfo.GetSetMethod().IsVirtual)
{
ParameterExpression valueExpr = Parameter(propInfo.PropertyType, "value");
var baseGet = Call(proxyBuilder.Base, propInfo.GetGetMethod());
proxyBuilder.OverrideMethod(propInfo.GetSetMethod(),
new[] { valueExpr },
If(NotEqual(baseGet, valueExpr),
Then(
If(IsNull(modifiedField),
Assign(modifiedField, New(typeof(HashSet <string>)))
),
Call("Add", modifiedField, Constant(propInfo.Name)),
Call(proxyBuilder.Base, propInfo.SetMethod, valueExpr)
)
)
);
}
}
proxyBuilder.DefineMethod("Reset", null,
Block(
If(IsNotNull(modifiedField),
Call("Clear", modifiedField)
)
)
);
var propNameParam = Parameter(typeof(string), "propName");
proxyBuilder.DefineMethod("IsSet",
new[] { propNameParam },
Block(
Variable("result", Constant(false), out Expression result),
If(IsNotNull(modifiedField),
Assign(result, Call("Contains", modifiedField, propNameParam))
),
Result(result)
)
);
proxyBuilder.AutoImplementInterface(typeof(IPatch));
return(proxyBuilder.Create());
}
public void call_base_method()
{
RuntimeTypeBuilder typeBuilder = new RuntimeTypeBuilder("CallBaseMethod", typeof(BaseMethodClass));
MethodInfo getTextInfo = typeof(BaseMethodClass).GetMethod("GetText");
typeBuilder.OverrideMethod(getTextInfo,
null,
Call("Concat", typeof(string), Call(typeBuilder.Base, getTextInfo), Constant(" (overriden)"))
);
Type newType = typeBuilder.Create();
object newInstance = Activator.CreateInstance(newType);
MethodInfo testMethodInfo = newType.GetMethod("GetText");
object result = testMethodInfo.Invoke(newInstance, null);
Assert.Equal("this is the base class! (overriden)", result);
}
public void override_property()
{
RuntimeTypeBuilder typeBuilder = new RuntimeTypeBuilder("OverrideProperty", typeof(BasePropertyClass));
PropertyInfo propInfo = typeof(BasePropertyClass).GetProperty("Text");
typeBuilder.OverrideMethod(propInfo.GetGetMethod(),
null,
Call("Concat", typeof(string), Call(typeBuilder.Base, propInfo.GetGetMethod()), Constant(" (overriden)"))
);
Type newType = typeBuilder.Create();
object newInstance = Activator.CreateInstance(newType);
propInfo.SetValue(newInstance, "this is a property!");
string result = (string)propInfo.GetValue(newInstance);
Assert.Equal("this is a property! (overriden)", result);
}
