IDL: Generate union type containers

Source/bindings/scripts/v8_methods.py

Index: Source/bindings/scripts/v8_methods.py
diff --git a/Source/bindings/scripts/v8_methods.py b/Source/bindings/scripts/v8_methods.py
index 299f6ba4fb007550992743fd1485162e0fc87655..cdcb3f20988c294206d8d89e5684108a09693d0c 100644
--- a/Source/bindings/scripts/v8_methods.py
+++ b/Source/bindings/scripts/v8_methods.py
@@ -178,7 +178,7 @@ def method_context(interface, method, is_visible=True):
         '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),
@@ -296,11 +296,6 @@ def cpp_value(interface, method, number_of_arguments):
         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')
@@ -309,9 +304,10 @@ def cpp_value(interface, method, number_of_arguments):
          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':
@@ -402,38 +398,24 @@ def property_attributes(method):
     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
-
-    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
-
-    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_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.
+    """
 
+    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),
+        }
 
-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):
@@ -443,8 +425,8 @@ def argument_default_cpp_value(argument):
         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)