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

{%- macro validate_not_null_ptr(field_expr, field, object_name) %}
if (!{{field_expr}}->offset) {
  ReportValidationError(
      mojo::internal::VALIDATION_ERROR_UNEXPECTED_NULL_POINTER,
      "null {{field.name}} field in {{object_name}}");
  return false;
}
{%- endmacro %}

{%- macro validate_encoded_ptr(field_expr) %}
if (!mojo::internal::ValidateEncodedPointer(&{{field_expr}}->offset)) {
  ReportValidationError(mojo::internal::VALIDATION_ERROR_ILLEGAL_POINTER);
  return false;
}
{%- endmacro %}

{%- macro validate_array_or_string(field_expr, field) -%}
const mojo::internal::ArrayValidateParams {{field.name}}_validate_params(
    {{field.kind|get_array_validate_params_ctor_args|indent(4)}});
if (!{{field.kind|cpp_wrapper_type}}::Data_::Validate(
        mojo::internal::DecodePointerRaw(&{{field_expr}}->offset),
        bounds_checker, &{{field.name}}_validate_params)) {
  return false;
}
{%- endmacro %}

{%- macro validate_handle(field_expr, field, object_name) -%}
  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) {
    ReportValidationError(
        mojo::internal::VALIDATION_ERROR_UNEXPECTED_INVALID_HANDLE,
        "invalid {{field.name}} field in {{object_name}}");
    return false;
  }
{%-   endif %}
  if (!bounds_checker->ClaimHandle({{field.name}}_handle)) {
    ReportValidationError(mojo::internal::VALIDATION_ERROR_ILLEGAL_HANDLE);
    return false;
  }
{%- endmacro -%}

{%- macro validate_union_field(field, union) %}
{%-   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) }}
{%-     endif %}
{{      validate_encoded_ptr(field_expr) }}
{%-   endif %}

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

{%-   if field.kind|is_any_handle_kind -%}
{{      validate_handle(field_expr, field, union.name) }}
{%-   endif %}
return true;
{%- endmacro %}