Implement unions as members of structs.

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

Index: mojo/public/tools/bindings/generators/cpp_templates/struct_macros.tmpl
diff --git a/mojo/public/tools/bindings/generators/cpp_templates/struct_macros.tmpl b/mojo/public/tools/bindings/generators/cpp_templates/struct_macros.tmpl
index 69c85949c293b08d1df51f6c6e6f59dfa8afbfbb..c69f4fb1bc3d605b3b9162cf349acb963c3ebf7b 100644
--- a/mojo/public/tools/bindings/generators/cpp_templates/struct_macros.tmpl
+++ b/mojo/public/tools/bindings/generators/cpp_templates/struct_macros.tmpl
@@ -10,17 +10,23 @@
 {%-   set kind = packed_field.field.kind %}
 {%-   set wrapper_type = kind|cpp_wrapper_type %}
 {%-   if not kind|is_nullable_kind %}
+{%-     if kind|is_union_kind %}
+  if (object->{{name}}.is_null()) {
+{%-     else %}
   if (!object->{{name}}.offset) {
+{%-     endif %}
     ReportValidationError(
         mojo::internal::VALIDATION_ERROR_UNEXPECTED_NULL_POINTER,
         "null {{name}} field in {{struct.name}} struct");
     return false;
   }
 {%-   endif %}
+{%-   if not kind|is_union_kind %}
   if (!mojo::internal::ValidateEncodedPointer(&object->{{name}}.offset)) {
     ReportValidationError(mojo::internal::VALIDATION_ERROR_ILLEGAL_POINTER);
     return false;
   }
+{%-   endif %}
 {%-   if kind|is_array_kind or kind|is_string_kind %}
   if (!{{wrapper_type}}::Data_::Validate<
           {{kind|get_array_validate_params|indent(10)}}>(
@@ -35,6 +41,10 @@
   if (!{{kind|get_name_for_kind}}::Data_::Validate(
           mojo::internal::DecodePointerRaw(&object->{{name}}.offset),
           bounds_checker)) {
+{%-   elif kind|is_union_kind %}
+  // We already claimed the union's memory as part of the struct, so we don't
+  // try to claim the union's memory when validating the union.
+  if (!{{kind.name}}::Data_::Validate(&object->{{name}}, bounds_checker, true)) {
 {%-   else %}
   if (!{{wrapper_type}}::Data_::Validate(
           mojo::internal::DecodePointerRaw(&object->{{name}}.offset),
@@ -167,7 +177,9 @@
 {%- macro encodes(struct) -%}
   MOJO_CHECK(header_.version == {{struct.versions[-1].version}});
 {%-   for pf in struct.packed.packed_fields_in_ordinal_order %}
-{%-     if pf.field.kind|is_object_kind %}
+{%-     if pf.field.kind|is_union_kind %}

[yzshen1, 2015/02/25 21:07:00]

Could you please move the "is_union_kind" part into the "is_object_kind" part?

[azani, 2015/03/03 00:44:16]

Done.

+// TODO(azani): Encode pointers and handles.
+{%-     elif pf.field.kind|is_object_kind %}
   mojo::internal::Encode(&{{pf.field.name}}, handles);
 {%-     elif pf.field.kind|is_any_handle_kind %}
   mojo::internal::EncodeHandle(&{{pf.field.name}}, handles);
@@ -195,7 +207,9 @@
   if (header_.version < {{pf.min_version}})
     return;
 {%-       endif %}
-{%-       if kind|is_object_kind %}
+{%-       if kind|is_union_kind %}

[yzshen1, 2015/02/25 21:07:00]

ditto

[azani, 2015/03/03 00:44:16]

Done.

+// TODO(azani): Decode pointers and handles.
+{%-       elif kind|is_object_kind %}
   mojo::internal::Decode(&{{name}}, handles);
 {%-       else %}
   mojo::internal::DecodeHandle(&{{name}}, handles);
@@ -243,7 +257,10 @@
 {%-   set input_field = input_field_pattern|format(pf.field.name) %}
 {%-   set name = pf.field.name %}
 {%-   set kind = pf.field.kind %}
-{%-   if kind|is_object_kind %}
+{%-   if kind|is_union_kind %}

[yzshen1, 2015/02/25 21:07:00]

ditto.

[azani, 2015/03/03 00:44:15]

Done.

+  internal::{{pf.field.kind.name}}_Data* {{pf.field.name}}_ptr = &result->{{pf.field.name}};

[yzshen1, 2015/02/25 21:07:00]

Please use {{input_field}}, {{buffer}} and {{output}} instead of "input->xxx",
"buf" and "result".

Besides, {{name}} and {{kind}} instead of {{pf.field.name}} and
{{pf.field.kind}}.

[azani, 2015/03/03 00:44:15]

Done.

+  Serialize_(mojo::internal::Forward(input->{{pf.field.name}}), buf, &{{pf.field.name}}_ptr);
+{%-   elif kind|is_object_kind %}
 {%-     if kind|is_array_kind %}
   mojo::SerializeArray_<{{kind|get_array_validate_params|indent(24)}}>(
       mojo::internal::Forward({{input_field}}), {{buffer}}, &{{output}}->{{name}}.ptr);
@@ -306,7 +323,9 @@
     if ({{input}}->header_.version < {{pf.min_version}})
       break;
 {%-     endif %}
-{%-     if kind|is_object_kind %}
+{%-     if kind|is_union_kind %}

[yzshen1, 2015/02/25 21:07:00]

Please move this if into the if for "is_object_kind".

[azani, 2015/03/03 00:44:16]

Done.

+    Deserialize_(&input->{{pf.field.name}}, &result->{{pf.field.name}});

[yzshen1, 2015/02/25 21:07:00]

Please use {{output_field}}, {{input}}.

Besides, {{name}} instead of {{pf.field.name}}

[azani, 2015/03/03 00:44:16]

Done.

+{%-     elif kind|is_object_kind %}
     Deserialize_({{input}}->{{name}}.ptr, &{{output_field}});
 {%-     elif kind|is_interface_kind or kind|is_interface_request_kind %}
     {{output_field}}.Bind(mojo::MakeScopedHandle(mojo::internal::FetchAndReset(&{{input}}->{{name}})));