Mojo cpp bindings: validation logic for incoming messages

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

+{%- macro validate(struct, class_name) %}
+  if (!data)
+    return true;
+
+  if (!ValidateStructHeader(
+          data, sizeof({{class_name}}),
+          {{struct.packed.packed_fields|length}}, bounds_checker)) {
+    return false;
+  }
+
+  const {{class_name}}* MOJO_ALLOW_UNUSED object =
+      static_cast<const {{class_name}}*>(data);
+
+{%-   for packed_field in struct.packed.packed_fields
+          if packed_field.field.kind|is_object_kind %}
+{%-     set wrapper_type = packed_field.field.kind|cpp_wrapper_type %}
+{%-     set name = packed_field.field.name %}
+  if (!mojo::internal::ValidateEncodedPointer(&object->{{name}}.offset) ||
+      !{{wrapper_type}}::Data_::Validate(
+          mojo::internal::DecodePointerRaw(&object->{{name}}.offset),
+          bounds_checker)) {
+    return false;
+  }
+{%-   endfor %}
+{%-   for packed_field in struct.packed.packed_fields
+          if packed_field.field.kind|is_handle_kind %}
+{%-     set name = packed_field.field.name %}
+  if (!bounds_checker->ClaimHandle(object->{{name}}))
+    return false;
+{%-   endfor %}
+
+  return true;
+{%- endmacro %}
+
 {%- macro field_line(field) %}
 {%-   set type = field.kind|cpp_field_type %}
 {%-   set name = field.name -%}
 {%-   if field.kind.spec == 'b' -%}
   uint8_t {{name}} : 1;
 {%-   elif field.kind|is_enum_kind -%}
   int32_t {{name}};
 {%-   else -%}
   {{type}} {{name}};
 {%-   endif %}
@@ skipping 35 matching lines @@
 {%-   for pf in struct.packed.packed_fields if pf.field.kind|is_object_kind -%}
 if (!mojo::internal::Decode(&{{pf.field.name}}, message))
   return false;
 {%    endfor %}
 {%-   for pf in struct.packed.packed_fields if pf.field.kind|is_handle_kind -%}
 if (!mojo::internal::DecodeHandle(&{{pf.field.name}},
                                   message->mutable_handles()))
   return false;
 {%    endfor %}
 {%- endmacro -%}