tools/bindings/generators/cpp_templates/validation_macros.tmpl

{# TODO(vardhan): Fill out the remaining validation error strings. #}
{%- macro validate_not_null_ptr(field_expr, field, object_name, err_string) %}
if (!{{field_expr}}->offset) {
  MOJO_INTERNAL_DEBUG_SET_ERROR_MSG({{err_string}})
    << "null field '{{field.name}}' in '{{object_name}}'"; 
  return mojo::internal::ValidationError::UNEXPECTED_NULL_POINTER;
}
{%- endmacro %}

{%- macro validate_encoded_ptr(field_expr, err_string) %}
if (!mojo::internal::ValidateEncodedPointer(&{{field_expr}}->offset)) {
  MOJO_INTERNAL_DEBUG_SET_ERROR_MSG({{err_string}}) << "";
  return mojo::internal::ValidationError::ILLEGAL_POINTER;
}
{%- endmacro %}

{%- macro validate_array_or_string(field_expr, field, err_string) -%}
const mojo::internal::ArrayValidateParams {{field.name}}_validate_params(
    {{field.kind|get_array_validate_params_ctor_args|indent(4)}});
auto validate_retval = {{field.kind|cpp_wrapper_type}}::Data_::Validate(
        mojo::internal::DecodePointerRaw(&{{field_expr}}->offset),
        bounds_checker, &{{field.name}}_validate_params,
        {{err_string}});
if (validate_retval != mojo::internal::ValidationError::NONE) {
  return validate_retval;
}
{%- endmacro %}

{%- macro validate_handle(field_expr, field, object_name, err_string) -%}
  const mojo::Handle {{field.name}}_handle(object->data.f_{{field.name}});

{%-   if not field.kind|is_nullable_kind %}
  if ({{field.name}}_handle.value() == mojo::internal::kEncodedInvalidHandleValue) {
    MOJO_INTERNAL_DEBUG_SET_ERROR_MSG({{err_string}})
       << "invalid {{field.name}} field in {{object_name}}";
    return mojo::internal::ValidationError::UNEXPECTED_INVALID_HANDLE;
  }
{%-   endif %}
  if (!bounds_checker->ClaimHandle({{field.name}}_handle)) {
    MOJO_INTERNAL_DEBUG_SET_ERROR_MSG({{err_string}}) << "";
    return mojo::internal::ValidationError::ILLEGAL_HANDLE;
  }
{%- endmacro -%}

{%- macro validate_union_field(field, union, err_string) %}
{%-   set field_expr = "(reinterpret_cast<const "
    ~ field.kind|cpp_union_field_type
    ~ "*>(&object->data.f_"
    ~ field.name
    ~ "))" -%}
{%-   if field.kind|is_object_kind -%}
{%-     if not field.kind|is_nullable_kind -%}
{{        validate_not_null_ptr(field_expr, field, union.name, err_string) }}
{%-     endif %}
{{      validate_encoded_ptr(field_expr, err_string) }}
{%-   endif %}

{%-   if field.kind|is_array_kind or field.kind|is_string_kind -%}
{{      validate_array_or_string(field_expr, field, err_string) }}
{%-   endif %}

{%-   if field.kind|is_any_handle_kind -%}
{{      validate_handle(field_expr, field, union.name, err_string) }}
{%-   endif %}
return mojo::internal::ValidationError::NONE;
{%- endmacro %}