API functions returning Promises should not throw exceptions.

Source/bindings/scripts/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 154 matching lines @@
         'is_callback_interface': idl_type.is_callback_interface,
         'is_nullable': idl_type.is_nullable,
         'is_optional': argument.is_optional,
         'is_strict_type_checking': 'StrictTypeChecking' in extended_attributes,
         'is_variadic_wrapper_type': is_variadic_wrapper_type,
         'vector_type': v8_types.cpp_ptr_type('Vector', 'HeapVector', idl_type.gc_type),
         'is_wrapper_type': idl_type.is_wrapper_type,
         'name': argument.name,
         'v8_set_return_value_for_main_world': v8_set_return_value(interface.name, method, this_cpp_value, for_main_world=True),
         'v8_set_return_value': v8_set_return_value(interface.name, method, this_cpp_value),
-        'v8_value_to_local_cpp_value': v8_value_to_local_cpp_value(argument, index),
+        'v8_value_to_local_cpp_value': v8_value_to_local_cpp_value(argument, index, async=False),

[Nils Barth (inactive), 2014/04/14 01:18:55]

Could you remove the async=False, since it's a default value?
(We don't want to clutter call sites just to support a special case.)

[yhirano, 2014/04/14 06:12:43]

Done.

+        'v8_value_to_local_cpp_value_async': v8_value_to_local_cpp_value(argument, index, async=True),
     }
 
 
 ################################################################################
 # Value handling
 ################################################################################
 
 def cpp_value(interface, method, number_of_arguments):
     def cpp_argument(argument):
         idl_type = argument.idl_type
@@ skipping 50 matching lines @@
         has_extended_attribute_value(method, 'CallWith', 'NewScriptState') or
         'RaisesException' in extended_attributes or
         idl_type.is_union_type):
         cpp_value = 'result'  # use local variable for value
         release = idl_type.release
 
     script_wrappable = 'impl' if inherits_interface(interface_name, 'Node') else ''
     return idl_type.v8_set_return_value(cpp_value, extended_attributes, script_wrappable=script_wrappable, release=release, for_main_world=for_main_world)
 
 
-def v8_value_to_local_cpp_value(argument, index):
+def v8_value_to_local_cpp_variadic_value(argument, index, async):
+    assert argument.is_variadic
+    idl_type = argument.idl_type
+    vector_type = v8_types.cpp_ptr_type('Vector', 'HeapVector', idl_type.gc_type)
+
+    macro = 'TONATIVE_VOID' + ('_ASYNC' if async else '')
+    macro_args = [
+      '%s<%s>' % (vector_type, idl_type.cpp_type),
+      argument.name,
+      'toNativeArguments<%s>(info, %s)' % (idl_type.cpp_type, index),
+    ]
+    if async:
+        macro_args.append('info')
+    return '%s(%s)' % (macro, ', '.join(macro_args))
+
+
+def v8_value_to_local_cpp_value(argument, index, async=False):
     extended_attributes = argument.extended_attributes
     idl_type = argument.idl_type
     name = argument.name
     if argument.is_variadic:
-        vector_type = v8_types.cpp_ptr_type('Vector', 'HeapVector', idl_type.gc_type)
-        return 'TONATIVE_VOID({vector_type}<{cpp_type}>, {name}, toNativeArguments<{cpp_type}>(info, {index}))'.format(
-            vector_type=vector_type, cpp_type=idl_type.cpp_type, name=name,
-            index=index)
+        return v8_value_to_local_cpp_variadic_value(argument, index, async)
     # [Default=NullString]
     if (argument.is_optional and idl_type.name == 'String' and
         extended_attributes.get('Default') == 'NullString'):
         v8_value = 'argumentOrNull(info, %s)' % index
     else:
         v8_value = 'info[%s]' % index
     return idl_type.v8_value_to_local_cpp_value(extended_attributes, v8_value,
-                                                name, index=index)
+                                                name, index=index, async=async)
 
 
 ################################################################################
 # Auxiliary functions
 ################################################################################
 
 # [NotEnumerable]
 def property_attributes(method):
     extended_attributes = method.extended_attributes
     property_attributes_list = []
     if 'NotEnumerable' in extended_attributes:
         property_attributes_list.append('v8::DontEnum')
     if 'ReadOnly' in extended_attributes:
         property_attributes_list.append('v8::ReadOnly')
     if property_attributes_list:
         property_attributes_list.insert(0, 'v8::DontDelete')
     return property_attributes_list
 
 
 def union_arguments(idl_type):
     """Return list of ['result0Enabled', 'result0', 'result1Enabled', ...] for union types, for use in setting return value"""
     return [arg
             for i in range(len(idl_type.member_types))
             for arg in ['result%sEnabled' % i, 'result%s' % i]]
 
 IdlType.union_arguments = property(lambda self: None)
 IdlUnionType.union_arguments = property(union_arguments)