IDL compiler: [Constructor] overloading

Source/bindings/scripts/unstable/v8_interface.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 76 matching lines @@
 
     # [SpecialWrapFor]
     if 'SpecialWrapFor' in extended_attributes:
         special_wrap_for = extended_attributes['SpecialWrapFor'].split('|')
     else:
         special_wrap_for = []
     for special_wrap_interface in special_wrap_for:
         v8_types.add_includes_for_type(special_wrap_interface)
 
     # Constructors
-    # [Constructor]
-    has_constructor = 'Constructor' in extended_attributes
-    if has_constructor:
+    constructors = [generate_constructor(interface, constructor)
+                    for constructor in interface.constructors]
+    generate_constructor_overloads(constructors)
+    if constructors:
         includes.add('bindings/v8/V8ObjectConstructor.h')
 
     # [EventConstructor]
     has_event_constructor = 'EventConstructor' in extended_attributes
     any_type_attributes = [attribute for attribute in interface.attributes
                            if attribute.idl_type == 'any']
     if has_event_constructor:
         includes.update(['bindings/v8/Dictionary.h',
                          'bindings/v8/V8ObjectConstructor.h'])
         if any_type_attributes:
             includes.add('bindings/v8/SerializedScriptValue.h')
 
     template_contents = {
         'any_type_attributes': any_type_attributes,
         'conditional_string': conditional_string(interface),  # [Conditional]
-        'constructor_argument_list': constructor_argument_list(interface),
-        'constructor_arguments': constructor_arguments(interface),
-        'constructor_method': {
-            'is_constructor': True,
-        },
+        'constructors': constructors,
         'cpp_class': cpp_name(interface),
         'generate_visit_dom_wrapper_function': generate_visit_dom_wrapper_function,
-        'has_constructor': has_constructor,
         'has_custom_legacy_call_as_function': has_extended_attribute_value(interface, 'Custom', 'LegacyCallAsFunction'),  # [Custom=LegacyCallAsFunction]
         'has_custom_to_v8': has_extended_attribute_value(interface, 'Custom', 'ToV8'),  # [Custom=ToV8]
         'has_custom_wrap': has_extended_attribute_value(interface, 'Custom', 'Wrap'),  # [Custom=Wrap]
         'has_event_constructor': has_event_constructor,
         'has_visit_dom_wrapper': (
             # [Custom=Wrap], [GenerateVisitDOMWrapper]
             has_extended_attribute_value(interface, 'Custom', 'VisitDOMWrapper') or
             'GenerateVisitDOMWrapper' in extended_attributes),
         'header_includes': header_includes,
-        'interface_length': interface_length(interface),
+        'interface_length': interface_length(interface, constructors),
         'interface_name': interface.name,
         'is_active_dom_object': 'ActiveDOMObject' in extended_attributes,  # [ActiveDOMObject]
         'is_check_security': is_check_security,
         'is_constructor_call_with_document': has_extended_attribute_value(
             interface, 'ConstructorCallWith', 'Document'),  # [ConstructorCallWith=Document]
         'is_constructor_call_with_execution_context': has_extended_attribute_value(
             interface, 'ConstructorCallWith', 'ExecutionContext'),  # [ConstructorCallWith=ExeuctionContext]
         'is_constructor_raises_exception': extended_attributes.get('RaisesException') == 'Constructor',  # [RaisesException=Constructor]
         'is_dependent_lifetime': 'DependentLifetime' in extended_attributes,  # [DependentLifetime]
         'measure_as': v8_utilities.measure_as(interface),  # [MeasureAs]
@@ skipping 165 matching lines @@
     if v8_types.is_wrapper_type(idl_type):
         type_check = 'V8{idl_type}::hasInstance({cpp_value}, info.GetIsolate(), worldType(info.GetIsolate()))'.format(idl_type=idl_type, cpp_value=cpp_value)
         if argument['is_nullable']:
             type_check = ' || '.join(['%s->IsNull()' % cpp_value, type_check])
         return type_check
     return None
 
 
 # Constructors
 
-def constructor_argument_list(interface):
-    if not interface.constructors:
-        return []
-    constructor = interface.constructors[0]  # FIXME: support overloading
+# [Constructor]
+def generate_constructor(interface, constructor):
+    return {
+        'argument_list': constructor_argument_list(interface, constructor),
+        'arguments': [constructor_argument(argument, index)
+                      for index, argument in enumerate(constructor.arguments)],
+        'is_constructor': True,
+        'is_variadic': False,

[haraken, 2013/12/13 10:23:31]

Do we need to specify these, even though their values are hard-coded as True or
False? (Probably they're used in template files.)

[Nils Barth (inactive), 2013/12/16 03:15:57]

Added a comment; it's required for overload resolution.
(Likewise for is_nullable and is_strict_type_checking.)

+        'number_of_required_arguments':
+            len([argument for argument in constructor.arguments
+                 if not argument.is_optional]),
+    }
 
+
+def constructor_argument_list(interface, constructor):
     arguments = []
     # [ConstructorCallWith=ExecutionContext]
     if has_extended_attribute_value(interface, 'ConstructorCallWith', 'ExecutionContext'):
         arguments.append('context')
     # [ConstructorCallWith=Document]
     if has_extended_attribute_value(interface, 'ConstructorCallWith', 'Document'):
         arguments.append('document')
 
     arguments.extend([argument.name for argument in constructor.arguments])
 
     # [RaisesException=Constructor]
     if interface.extended_attributes.get('RaisesException') == 'Constructor':
         arguments.append('exceptionState')
 
     return arguments
 
 
-def constructor_arguments(interface):
-    if not interface.constructors:
-        return []
-    constructor = interface.constructors[0]  # FIXME: support overloading
-    return [constructor_argument(argument, index)
-            for index, argument in enumerate(constructor.arguments)]
-
-
 def constructor_argument(argument, index):
     return {
         'idl_type': argument.idl_type,
         'index': index,
+        'is_nullable': False,

[Nils Barth (inactive), 2013/12/13 07:04:16]

Stubs for overload resolution.

+        'is_optional': argument.is_optional,
+        'is_strict_type_checking': False,
         'name': argument.name,
         'v8_value_to_local_cpp_value':
             v8_methods.v8_value_to_local_cpp_value(argument, index),
     }
 
 
-def interface_length(interface):
+def generate_constructor_overloads(constructors):
+    if len(constructors) < 2:

[haraken, 2013/12/13 10:23:31]

Nit: I'd prefer '<= 1'

[Nils Barth (inactive), 2013/12/16 03:15:57]

n/p, done.

+        return
+    for overload_index, constructor in enumerate(constructors):
+        constructor.update({
+            'overload_index': overload_index + 1,
+            'overload_resolution_expression':
+                overload_resolution_expression(constructor),
+        })
+
+
+def interface_length(interface, constructors):
     # Docs: http://heycam.github.io/webidl/#es-interface-call
     if 'EventConstructor' in interface.extended_attributes:
         return 1
-    if not interface.constructors:
+    if not constructors:
         return 0
-    constructor = interface.constructors[0]  # FIXME: support overloading
-    return len([argument
-                for argument in constructor.arguments
-                if not argument.is_optional])
+    return min(constructor['number_of_required_arguments']
+               for constructor in constructors)