Mojo C++ bindings: allow StructTraits to return handle or interface types as value.

mojo/public/tools/bindings/generators/cpp_templates/struct_macros.tmpl

 {#  TODO(yzshen): Make these templates more readable. #}
 
 {#  Computes the serialized size for the specified struct.
     |struct| is the struct definition.
     |input_field_pattern| should be a pattern that contains one string
     placeholder, for example, "input->%s", "p_%s". The placeholder will be
     substituted with struct field names to refer to the input fields.
     |context| is the name of the serialization context.
     |input_may_be_temp| indicates whether any input may be temporary obejcts.
     We need to assign temporary objects to local variables before passing it to
@@ skipping 48 matching lines @@
 {%- macro serialize(struct, struct_display_name, input_field_pattern, output,
                     buffer, context, input_may_be_temp=False) -%}
   auto {{output}} =
       {{struct|get_qualified_name_for_kind(internal=True)}}::New({{buffer}});
   ALLOW_UNUSED_LOCAL({{output}});
 {%- for pf in struct.packed.packed_fields_in_ordinal_order %}
 {%-   set input_field = input_field_pattern|format(pf.field.name) %}
 {%-   set name = pf.field.name %}
 {%-   set kind = pf.field.kind %}
 {%-   set serializer_type = kind|unmapped_type_for_serializer %}
-{%-   if kind|is_object_kind %}
+
+{%-   if kind|is_object_kind or kind|is_any_handle_or_interface_kind %}
 {%-     set original_input_field = input_field_pattern|format(name) %}
 {%-     set input_field = "in_%s"|format(name) if input_may_be_temp
                                                else original_input_field %}
 {%-     if input_may_be_temp %}
   decltype({{original_input_field}}) in_{{name}} = {{original_input_field}};
 {%-     endif %}
+{%-   endif %}
+
+{%-   if kind|is_object_kind %}
 {%-     if kind|is_array_kind or kind|is_map_kind %}

[Peng, 2016/07/06 18:05:26]

This code is totally unreadable to me. Maybe ask other to take a look.

[yzshen1, 2016/07/06 18:07:25]

I am the author of most of the code in this folder. :)
If you think it does what you want, would you please LG this CL.

   typename decltype({{output}}->{{name}})::BaseType* {{name}}_ptr;
   const mojo::internal::ContainerValidateParams {{name}}_validate_params(
       {{kind|get_container_validate_params_ctor_args|indent(10)}});
   mojo::internal::Serialize<{{serializer_type}}>(
       {{input_field}}, {{buffer}}, &{{name}}_ptr, &{{name}}_validate_params,
       {{context}});
   {{output}}->{{name}}.Set({{name}}_ptr);
 {%-     elif kind|is_union_kind %}
   auto {{name}}_ptr = &{{output}}->{{name}};
   mojo::internal::Serialize<{{serializer_type}}>(
@@ skipping 57 matching lines @@
 {%-     if kind|is_object_kind or kind|is_enum_kind %}
   if (!{{input}}.Read{{name|under_to_camel}}(&{{output_field}}))
     {{success}} = false;
 {%-     elif kind|is_any_handle_or_interface_kind %}
   {{output_field}} = {{input}}.Take{{name|under_to_camel}}();
 {%-     else %}
   {{output_field}} = {{input}}.{{name}}();
 {%-     endif %}
 {%-   endfor %}
 {%- endmacro %}