private void LoadParameterOrNull(ParameterInfo pi, Type type)
{
EmitHelper emit = Context.MethodBuilder.Emitter;
object[] attrs = pi.GetCustomAttributes(typeof(ParamNullValueAttribute), true);
object nullValue = attrs.Length == 0?
null: ((ParamNullValueAttribute)attrs[0]).Value;
Label labelNull = emit.DefineLabel();
Label labelEndIf = emit.DefineLabel();
if (pi.Attributes == ParameterAttributes.Out)
{
emit
.ldnull
.end()
;
return;
}
if (nullValue != null)
{
Type nullValueType = type;
bool isNullable = TypeHelper.IsNullable(type);
if (type.IsEnum)
{
nullValueType = Enum.GetUnderlyingType(type);
nullValue = System.Convert.ChangeType(nullValue, nullValueType);
}
else if (isNullable)
{
nullValueType = type.GetGenericArguments()[0];
emit
.ldarga (pi)
.call (type, "get_HasValue")
.brfalse (labelNull)
;
}
if (nullValueType == nullValue.GetType() && emit.LoadWellKnownValue(nullValue))
{
if (nullValueType == typeof(string))
emit
.ldargEx (pi, false)
.call (nullValueType, "Equals", nullValueType)
.brtrue (labelNull)
;
else if (isNullable)
emit
.ldarga (pi)
.call (type, "get_Value")
.beq (labelNull)
;
else
emit
.ldargEx (pi, false)
.beq (labelNull)
;
}
else
{
string nullString = TypeDescriptor.GetConverter(nullValue).ConvertToInvariantString(nullValue);
FieldBuilder staticField = CreateNullValueField(nullValueType, nullString);
MethodInfo miEquals = new TypeHelper(nullValueType).GetPublicMethod("Equals", nullValueType);
if (miEquals == null)
{
// Is it possible?
//
throw new TypeBuilderException(string.Format(
Resources.DataAccessorBuilder_EqualsMethodIsNotPublic, type.FullName));
}
if (isNullable)
emit
.ldsflda (staticField)
.ldarga (pi)
.call (pi.ParameterType, "get_Value")
;
else
emit
.ldsflda (staticField)
.ldarg (pi)
;
if (miEquals.GetParameters()[0].ParameterType.IsClass)
emit
.boxIfValueType(nullValueType)
;
emit
.call (miEquals)
.brtrue (labelNull)
;
}
}
if (type.IsEnum)
emit
.ldloc (_locManager)
.callvirt (typeof (DbManager).GetProperty("MappingSchema").GetGetMethod())
;
emit
.ldargEx(pi, true)
;
if (type.IsEnum)
emit
.ldc_i4_1
.callvirt (typeof (MappingSchema), "MapEnumToValue", typeof (object), typeof (bool))
;
if (nullValue != null)
{
emit
.br (labelEndIf)
.MarkLabel (labelNull)
.ldnull
.MarkLabel (labelEndIf)
;
}
}
