IDL compiler: [Default] arguments

Source/bindings/scripts/unstable/v8_methods.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 47 matching lines @@
     return contents
 
 
 def generate_argument(method, argument, index):
     extended_attributes = argument.extended_attributes
     idl_type = argument.idl_type
     return {
         'cpp_method': cpp_method(method, index),
         'cpp_type': v8_types.cpp_type(idl_type),
         'enum_validation_expression': v8_utilities.enum_validation_expression(idl_type),
+        'has_default': 'Default' in extended_attributes,
         'idl_type': argument.idl_type,
         'index': index,
         'is_clamp': 'Clamp' in extended_attributes,
         'is_optional': argument.is_optional,
         'is_variadic_wrapper_type': argument.is_variadic and v8_types.is_wrapper_type(idl_type),
         'name': argument.name,
         'v8_value_to_local_cpp_value': v8_value_to_local_cpp_value(argument, index),
     }
 
 
@@ skipping 19 matching lines @@
     def argument_template(argument):
         idl_type = argument.idl_type
         if (v8_types.is_wrapper_type(idl_type) and
             not v8_types.is_typed_array_type(idl_type) and
             # Compatibility: all other browsers accepts a callable for
             # XPathNSResolver, despite it being against spec.
             not idl_type == 'XPathNSResolver'):
             return 'V8PerIsolateData::from(isolate)->rawTemplate(&V8{idl_type}::wrapperTypeInfo, currentWorldType)'.format(idl_type=idl_type)
         return 'v8::Handle<v8::FunctionTemplate>()'
 
-    if (any(argument.is_optional for argument in arguments) or
+    if (any(argument.is_optional and
+            'Default' not in argument.extended_attributes
+            for argument in arguments) or
         all(not v8_types.is_wrapper_type(argument.idl_type)
             for argument in arguments)):
         return None
     return ', '.join([argument_template(argument) for argument in arguments])
 
 
 def v8_value_to_local_cpp_value(argument, index):
+    extended_attributes = argument.extended_attributes
     idl_type = argument.idl_type
     name = argument.name
     if argument.is_variadic:
         return 'V8TRYCATCH_VOID(Vector<{cpp_type}>, {name}, toNativeArguments<{cpp_type}>(args, {index}))'.format(
                 cpp_type=v8_types.cpp_type(idl_type), name=name, index=index)
+    if (argument.is_optional and idl_type == 'DOMString' and
+        extended_attributes.get('Default') == 'NullString'):
+        v8_value = 'argumentOrNull(args, %s)' % index
+    else:
+        v8_value = 'args[%s]' % index
     return v8_types.v8_value_to_local_cpp_value(
-        idl_type, argument.extended_attributes,
-        'args[%s]' % index, name, 'args.GetIsolate()', index=index)
+        idl_type, argument.extended_attributes, v8_value, name,
+        'args.GetIsolate()', index=index)