ObjectScanner CreateScanner(Type type)
{
bool isArray = type.IsArray;
if (isArray) {
if (type.GetArrayRank() != 1)
throw new NotSupportedException();
type = type.GetElementType();
if (!type.IsValueType) {
return delegate (SerializationContext context, object array) {
foreach (object val in (object[])array) {
context.Mark(val);
}
};
}
}
for (Type baseType = type; baseType != null; baseType = baseType.BaseType) {
if (!baseType.IsSerializable)
throw new SerializationException("Type " + baseType + " is not [Serializable].");
}
List<FieldInfo> fields = GetSerializableFields(type);
fields.RemoveAll(f => !IsReferenceOrContainsReferences(f.FieldType));
if (fields.Count == 0) {
// The scanner has nothing to do for this object.
return delegate { };
}
DynamicMethod dynamicMethod = new DynamicMethod(
(isArray ? "ScanArray_" : "Scan_") + type.Name,
typeof(void), new [] { typeof(SerializationContext), typeof(object) },
true);
ILGenerator il = dynamicMethod.GetILGenerator();
if (isArray) {
var instance = il.DeclareLocal(type.MakeArrayType());
il.Emit(OpCodes.Ldarg_1);
il.Emit(OpCodes.Castclass, type.MakeArrayType());
il.Emit(OpCodes.Stloc, instance); // instance = (type[])arg_1;
// for (int i = 0; i < instance.Length; i++) scan instance[i];
var loopStart = il.DefineLabel();
var loopHead = il.DefineLabel();
var loopVariable = il.DeclareLocal(typeof(int));
il.Emit(OpCodes.Ldc_I4_0);
il.Emit(OpCodes.Stloc, loopVariable); // loopVariable = 0
il.Emit(OpCodes.Br, loopHead); // goto loopHead;
il.MarkLabel(loopStart);
il.Emit(OpCodes.Ldloc, instance); // instance
il.Emit(OpCodes.Ldloc, loopVariable); // instance, loopVariable
il.Emit(OpCodes.Ldelem, type); // &instance[loopVariable]
EmitScanValueType(il, type);
il.Emit(OpCodes.Ldloc, loopVariable); // loopVariable
il.Emit(OpCodes.Ldc_I4_1); // loopVariable, 1
il.Emit(OpCodes.Add); // loopVariable+1
il.Emit(OpCodes.Stloc, loopVariable); // loopVariable++;
il.MarkLabel(loopHead);
il.Emit(OpCodes.Ldloc, loopVariable); // loopVariable
il.Emit(OpCodes.Ldloc, instance); // loopVariable, instance
il.Emit(OpCodes.Ldlen); // loopVariable, instance.Length
il.Emit(OpCodes.Conv_I4);
il.Emit(OpCodes.Blt, loopStart); // if (loopVariable < instance.Length) goto loopStart;
} else if (type.IsValueType) {
// boxed value type
il.Emit(OpCodes.Ldarg_1);
il.Emit(OpCodes.Unbox_Any, type);
EmitScanValueType(il, type);
} else {
// reference type
var instance = il.DeclareLocal(type);
il.Emit(OpCodes.Ldarg_1);
il.Emit(OpCodes.Castclass, type);
il.Emit(OpCodes.Stloc, instance); // instance = (type)arg_1;
foreach (FieldInfo field in fields) {
EmitScanField(il, instance, field); // scan instance.Field
}
}
il.Emit(OpCodes.Ret);
return (ObjectScanner)dynamicMethod.CreateDelegate(typeof(ObjectScanner));
}
