IDL: Generate union type containers

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 160 matching lines @@
             argument for argument in arguments
             if not argument.is_optional]),
         'only_exposed_to_private_script': is_only_exposed_to_private_script,
         'per_context_enabled_function': v8_utilities.per_context_enabled_function_name(method),  # [PerContextEnabled]
         'private_script_v8_value_to_local_cpp_value': idl_type.v8_value_to_local_cpp_value(
             extended_attributes, 'v8Value', 'cppValue', isolate='scriptState->isolate()', used_in_private_script=True),
         'property_attributes': property_attributes(method),
         'runtime_enabled_function': v8_utilities.runtime_enabled_function_name(method),  # [RuntimeEnabled]
         'should_be_exposed_to_script': not (is_implemented_in_private_script and is_only_exposed_to_private_script),
         'signature': 'v8::Local<v8::Signature>()' if is_static or 'DoNotCheckSignature' in extended_attributes else 'defaultSignature',
-        'union_arguments': idl_type.union_arguments,
+        'union_result_members': idl_type.union_result_members,
         'use_output_parameter_for_result': idl_type.is_dictionary,
         'use_local_result': use_local_result(method),
         'v8_set_return_value': v8_set_return_value(interface.name, method, this_cpp_value),
         'v8_set_return_value_for_main_world': v8_set_return_value(interface.name, method, this_cpp_value, for_main_world=True),
         'visible': is_visible,
         'world_suffixes': ['', 'ForMainWorld'] if 'PerWorldBindings' in extended_attributes else [''],  # [PerWorldBindings],
     }
 
 
 def argument_context(interface, method, argument, index):
@@ skipping 97 matching lines @@
 
     # Members of IDL partial interface definitions are implemented in C++ as
     # static member functions, which for instance members (non-static members)
     # take *impl as their first argument
     if ('PartialInterfaceImplementedAs' in method.extended_attributes and
         not 'ImplementedInPrivateScript' in method.extended_attributes and
         not method.is_static):
         cpp_arguments.append('*impl')
     cpp_arguments.extend(cpp_argument(argument) for argument in arguments)
 
-    this_union_arguments = method.idl_type and method.idl_type.union_arguments
-    if this_union_arguments:
-        cpp_arguments.extend([member_argument['cpp_value']
-                              for member_argument in this_union_arguments])
-
     if 'ImplementedInPrivateScript' in method.extended_attributes:
         if method.idl_type.name != 'void':
             cpp_arguments.append('&result')
     elif ('RaisesException' in method.extended_attributes or
         (method.is_constructor and
          has_extended_attribute_value(interface, 'RaisesException', 'Constructor'))):
         cpp_arguments.append('exceptionState')
 
-    # If a method returns an IDL dictionary, the return value is passed
-    # as an argument to impl classes.
-    if method.idl_type and method.idl_type.is_dictionary:
+    # If a method returns an IDL dictionary or union type, the return value is
+    # passed as an argument to impl classes.
+    idl_type = method.idl_type
+    if idl_type and (idl_type.is_dictionary or idl_type.is_union_type):
         cpp_arguments.append('result')
 
     if method.name == 'Constructor':
         base_name = 'create'
     elif method.name == 'NamedConstructor':
         base_name = 'createForJSConstructor'
     elif 'ImplementedInPrivateScript' in method.extended_attributes:
         base_name = '%sMethod' % method.name
     else:
         base_name = v8_utilities.cpp_name(method)
@@ skipping 70 matching lines @@
     property_attributes_list = []
     if 'NotEnumerable' in extended_attributes:
         property_attributes_list.append('v8::DontEnum')
     if 'Unforgeable' 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_member_argument_context(idl_type, index):
-    """Returns a context of union member for argument."""
-    this_cpp_value = 'result%d' % index
-    this_cpp_type = idl_type.cpp_type
-    this_cpp_type_initializer = idl_type.cpp_type_initializer
-    cpp_return_value = this_cpp_value
+def union_result_members_context(idl_type):
+    """Returns a context of return value for methods/getters of which type

[Jens Widell, 2014/10/28 11:31:38]

I think "a context" here is expected to be a dict, not a list. This method
returns a list of contexts.

So like in the old code, it might be better to call this method
union_result_members() (and the inner/helper method
union_result_member_context(), as now.)

[bashi, 2014/10/29 01:34:32]

Now we no longer need this method :)

+    is an union type. If a method/getter returns an union type, the impl class
+    takes 'result' argument of which type is the corresponding container class.
+    """
 
-    if not idl_type.cpp_type_has_null_value:
-        this_cpp_type = v8_types.cpp_template_type('Nullable', this_cpp_type)
-        this_cpp_type_initializer = ''
-        cpp_return_value = '%s.get()' % this_cpp_value
+    def union_result_member_context(idl_type):
+        cpp_value = 'result.getAs%s()' % idl_type.name
+        if idl_type.is_explicit_nullable:
+            cpp_value = '%s.get()' % cpp_value

[Jens Widell, 2014/10/28 11:31:37]

Could be

  cpp_value += '.get()'

too, which is easier on the eyes, I think. (I also often use string formatting
in lots of situations where simple concatenation would probably be better.)

+        return {
+            'null_check_value': 'result.is%s()' % idl_type.name,
+            'v8_set_return_value': idl_type.v8_set_return_value(
+                cpp_value=cpp_value),
+        }
 
-    if idl_type.is_string_type:
-        null_check_value = '!%s.isNull()' % this_cpp_value
-    else:
-        null_check_value = this_cpp_value
-
-    return {
-        'cpp_type': this_cpp_type,
-        'cpp_type_initializer': this_cpp_type_initializer,
-        'cpp_value': this_cpp_value,
-        'null_check_value': null_check_value,
-        'v8_set_return_value': idl_type.v8_set_return_value(
-            cpp_value=cpp_return_value,
-            release=idl_type.release),
-    }
-
-
-def union_arguments(idl_type):
-    return [union_member_argument_context(member_idl_type, index)
-            for index, member_idl_type
-            in enumerate(idl_type.member_types)]
+    return [union_result_member_context(member_idl_type)
+            for member_idl_type in idl_type.member_types]
 
 
 def argument_default_cpp_value(argument):
     if argument.idl_type.is_dictionary:
         return None
     if not argument.default_value:
         return None
     return argument.idl_type.literal_cpp_value(argument.default_value)
 
-IdlTypeBase.union_arguments = None
-IdlUnionType.union_arguments = property(union_arguments)
+IdlTypeBase.union_result_members = None
+IdlUnionType.union_result_members = property(union_result_members_context)
 IdlArgument.default_cpp_value = property(argument_default_cpp_value)
 
 
 def method_returns_promise(method):
     return method.idl_type and method.idl_type.name == 'Promise'
 
 IdlOperation.returns_promise = property(method_returns_promise)
 
 
 def argument_conversion_needs_exception_state(method, argument):
     idl_type = argument.idl_type
     return (idl_type.v8_conversion_needs_exception_state or
             argument.is_variadic or
             (method.returns_promise and (idl_type.is_string_type or
                                          idl_type.is_enum)))