IDL: Support using nullable on any method return type

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 49 matching lines @@
         # generate_argument() macro in Source/bindings/templates/methods.cpp.
         idl_type.is_callback_interface or
         base_type == 'SerializedScriptValue' or
         (argument.is_variadic and idl_type.is_wrapper_type) or
         # String and enumeration arguments converted using one of the
         # TOSTRING_* macros in Source/bindings/core/v8/V8BindingMacros.h don't
         # use a v8::TryCatch.
         (base_type == 'DOMString' and not argument.is_variadic))
 
 
+def use_result_local(method):

[haraken, 2014/07/10 15:21:37]

use_result_local => use_local_result

[Jens Widell, 2014/07/10 15:28:53]

Done.

+    extended_attributes = method.extended_attributes
+    idl_type = method.idl_type
+    return (has_extended_attribute_value(method, 'CallWith', 'ScriptState') or
+            'ImplementedInPrivateScript' in extended_attributes or
+            'RaisesException' in extended_attributes or
+            idl_type.is_union_type or
+            (idl_type.is_nullable and not idl_type.is_nullable_simple))
+
+
 def method_context(interface, method):
     arguments = method.arguments
     extended_attributes = method.extended_attributes
     idl_type = method.idl_type
     is_static = method.is_static
     name = method.name
 
     idl_type.add_includes_for_type()
     this_cpp_value = cpp_value(interface, method, len(arguments))
 
@@ skipping 23 matching lines @@
         includes.add('core/dom/custom/CustomElementCallbackDispatcher.h')
 
     is_check_security_for_frame = (
         'CheckSecurity' in interface.extended_attributes and
         'DoNotCheckSecurity' not in extended_attributes)
     is_raises_exception = 'RaisesException' in extended_attributes
 
     arguments_need_try_catch = any(argument_needs_try_catch(argument)
                                    for argument in arguments)
 
+    is_nullable = idl_type.is_nullable and not idl_type.is_nullable_simple
+
     return {
         'activity_logging_world_list': v8_utilities.activity_logging_world_list(method),  # [ActivityLogging]
         'arguments': [argument_context(interface, method, argument, index)
                       for index, argument in enumerate(arguments)],
         'argument_declarations_for_private_script':
             argument_declarations_for_private_script(interface, method),
         'arguments_need_try_catch': arguments_need_try_catch,
         'conditional_string': v8_utilities.conditional_string(method),
-        'cpp_type': idl_type.cpp_type,
+        'cpp_type': (v8_types.cpp_template_type('Nullable', idl_type.cpp_type)
+                     if is_nullable else idl_type.cpp_type),
         'cpp_value': this_cpp_value,
         'custom_registration_extended_attributes':
             CUSTOM_REGISTRATION_EXTENDED_ATTRIBUTES.intersection(
                 extended_attributes.iterkeys()),
         'deprecate_as': v8_utilities.deprecate_as(method),  # [DeprecateAs]
         'function_template': function_template(),
         'has_custom_registration': is_static or
             v8_utilities.has_extended_attribute(
                 method, CUSTOM_REGISTRATION_EXTENDED_ATTRIBUTES),
         'has_exception_state':
             is_raises_exception or
             is_check_security_for_frame or
             interface.name == 'EventTarget' or  # FIXME: merge with is_check_security_for_frame http://crbug.com/383699
             any(argument for argument in arguments
                 if argument.idl_type.name == 'SerializedScriptValue' or
                    argument.idl_type.may_raise_exception_on_conversion),
         'idl_type': idl_type.base_type,
         'is_call_with_execution_context': has_extended_attribute_value(method, 'CallWith', 'ExecutionContext'),
         'is_call_with_script_arguments': is_call_with_script_arguments,
         'is_call_with_script_state': is_call_with_script_state,
         'is_check_security_for_frame': is_check_security_for_frame,
         'is_check_security_for_node': is_check_security_for_node,
         'is_custom': 'Custom' in extended_attributes,
         'is_custom_element_callbacks': is_custom_element_callbacks,
         'is_do_not_check_security': 'DoNotCheckSecurity' in extended_attributes,
         'is_do_not_check_signature': 'DoNotCheckSignature' in extended_attributes,
         'is_implemented_in_private_script': is_implemented_in_private_script,
+        'is_nullable': is_nullable,
         'is_partial_interface_member':
             'PartialInterfaceImplementedAs' in extended_attributes,
         'is_per_world_bindings': 'PerWorldBindings' in extended_attributes,
         'is_raises_exception': is_raises_exception,
         'is_read_only': 'Unforgeable' in extended_attributes,
         'is_static': is_static,
+        'is_use_result_local': use_result_local(method),

[haraken, 2014/07/10 15:21:37]

is_use_result_local => use_local_result

[Jens Widell, 2014/07/10 15:28:53]

Done.

         'is_variadic': arguments and arguments[-1].is_variadic,
         'measure_as': v8_utilities.measure_as(method),  # [MeasureAs]
         'name': name,
         'number_of_arguments': len(arguments),
         'number_of_required_arguments': len([
             argument for argument in arguments
             if not (argument.is_optional or argument.is_variadic)]),
         'number_of_required_or_variadic_arguments': len([
             argument for argument in arguments
             if not argument.is_optional]),
@@ skipping 145 matching lines @@
         # Constructors and void methods don't have a return type
         return None
 
     if ('ImplementedInPrivateScript' in extended_attributes and
         not idl_type.is_wrapper_type and
         not idl_type.is_basic_type):
         raise Exception('Private scripts supports only primitive types and DOM wrappers.')
 
     release = False
     # [CallWith=ScriptState], [RaisesException]
-    if (has_extended_attribute_value(method, 'CallWith', 'ScriptState') or
-        'ImplementedInPrivateScript' in extended_attributes or
-        'RaisesException' in extended_attributes or
-        idl_type.is_union_type):
-        cpp_value = 'result'  # use local variable for value
+    if use_result_local(method):
+        if idl_type.is_nullable and not idl_type.is_nullable_simple:
+            # result is of type Nullable<T>
+            cpp_value = 'result.get()'
+        else:
+            cpp_value = 'result'
         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_variadic_value(argument, index):
     assert argument.is_variadic
     idl_type = argument.idl_type
 
@@ skipping 41 matching lines @@
 
 
 def argument_default_cpp_value(argument):
     if not argument.default_value:
         return None
     return argument.idl_type.literal_cpp_value(argument.default_value)
 
 IdlType.union_arguments = property(lambda self: None)
 IdlUnionType.union_arguments = property(union_arguments)
 IdlArgument.default_cpp_value = property(argument_default_cpp_value)