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.
    This macro is expanded to compute seriailized size for both:
    - user-defined structs: the input is an instance of the corresponding struct
      wrapper class.
    - method parameters/response parameters: the input is a list of
      arguments.
    It declares |size| of type size_t to store the resulting size. #}
{%- macro get_serialized_size(struct, input_field_pattern) -%}
  size_t size = sizeof(internal::{{struct.name}}_Data);
{%-   for pf in struct.packed.packed_fields_in_ordinal_order if pf.field.kind|is_object_kind %}
{%-     if pf.field.kind|is_union_kind %}
  size += GetSerializedSize_({{input_field_pattern|format(pf.field.name)}}, true);
{%-     else %}
  size += GetSerializedSize_({{input_field_pattern|format(pf.field.name)}});
{%-     endif %}
{%-   endfor %}
{%- endmacro -%}

{#  Serializes the specified struct.
    |struct| is the struct definition.
    |struct_display_name| is the display name for the struct that can be showed
    in error/log messages, for example, "FooStruct", "FooMethod request".
    |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.
    |output| is the name of the output struct instance.
    |buffer| is the name of the Buffer instance used.
    This macro is expanded to do serialization for both:
    - user-defined structs: the input is an instance of the corresponding struct
      wrapper class.
    - method parameters/response parameters: the input is a list of
      arguments. #}
{%- macro serialize(struct, struct_display_name, input_field_pattern, output, buffer) -%}
  internal::{{struct.name}}_Data* {{output}} =
      internal::{{struct.name}}_Data::New({{buffer}});
{%- 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 %}
{%-   if kind|is_object_kind %}
{%-     if kind|is_array_kind %}
  const mojo::internal::ArrayValidateParams {{name}}_validate_params(
      {{kind|get_array_validate_params_ctor_args|indent(10)}});
  mojo::SerializeArray_(mojo::internal::Forward({{input_field}}), {{buffer}},
      &{{output}}->{{name}}.ptr, &{{name}}_validate_params);
{%-     elif kind|is_map_kind %}
  const mojo::internal::ArrayValidateParams {{name}}_validate_params(
      {{kind.value_kind|get_map_validate_params_ctor_args|indent(10)}});
  mojo::SerializeMap_(
      mojo::internal::Forward({{input_field}}), {{buffer}}, &{{output}}->{{name}}.ptr,
      &{{name}}_validate_params);
{%-     elif kind|is_union_kind %}
  internal::{{kind.name}}_Data* {{name}}_ptr = &{{output}}->{{name}};
  SerializeUnion_(mojo::internal::Forward({{input_field}}), {{buffer}}, &{{name}}_ptr, true);
{%-     else %}
  Serialize_(mojo::internal::Forward({{input_field}}), {{buffer}}, &{{output}}->{{name}}.ptr);
{%-     endif %}
{%-     if not kind|is_nullable_kind %}
  MOJO_INTERNAL_DLOG_SERIALIZATION_WARNING(
{%-       if kind|is_union_kind %}
      {{output}}->{{name}}.is_null(),
{%-       else %}
      !{{output}}->{{name}}.ptr,
{%-       endif %}
      mojo::internal::VALIDATION_ERROR_UNEXPECTED_NULL_POINTER,
      "null {{name}} in {{struct_display_name}}");
{%-     endif %}
{%-   elif kind|is_any_handle_kind or kind|is_interface_kind %}
{%-     if kind|is_interface_kind %}
  mojo::internal::InterfacePointerToData({{input_field}}.Pass(), &{{output}}->{{name}});
{%-     elif kind|is_interface_request_kind %}
  {{output}}->{{name}} = {{input_field}}.PassMessagePipe().release();
{%-     else %}
  {{output}}->{{name}} = {{input_field}}.release();
{%-     endif %}
{%-     if not kind|is_nullable_kind %}
  MOJO_INTERNAL_DLOG_SERIALIZATION_WARNING(
{%-       if kind|is_interface_kind %}
      !{{output}}->{{name}}.handle.is_valid(),
{%-       else %}
      !{{output}}->{{name}}.is_valid(),
{%-       endif %}
      mojo::internal::VALIDATION_ERROR_UNEXPECTED_INVALID_HANDLE,
      "invalid {{name}} in {{struct_display_name}}");
{%-     endif %}
{%-   else %}
  {{output}}->{{name}} = {{input_field}};
{%-   endif %}
{%- endfor %}
{%- endmacro -%}

{#  Deserializes the specified struct.
    |struct| is the struct definition.
    |input| is the name of the input struct instance.
    |output_field_pattern| should be a pattern that contains one string
    placeholder, for example, "result->%s", "p_%s". The placeholder will be
    substituted with struct field names to refer to the output fields.
    This macro is expanded to do deserialization for both:
    - user-defined structs: the output is an instance of the corresponding
      struct wrapper class.
    - method parameters/response parameters: the output is a list of
      arguments. #}
{%- macro deserialize(struct, input, output_field_pattern) -%}
  do {
    // NOTE: The memory backing |{{input}}| may has be smaller than
    // |sizeof(*{{input}})| if the message comes from an older version.
{#-   Before deserialize fields introduced at a certain version, we need to add
      a version check, which makes sure we skip further deserialization if
      |input| is from an earlier version. |last_checked_version| records the
      last version that we have added such version check. #}
{%-   set last_checked_version = 0 %}
{%-   for pf in struct.packed.packed_fields_in_ordinal_order %}
{%-     set output_field = output_field_pattern|format(pf.field.name) %}
{%-     set name = pf.field.name %}
{%-     set kind = pf.field.kind %}
{%-     if pf.min_version > last_checked_version %}
{%-       set last_checked_version = pf.min_version %}
    if ({{input}}->header_.version < {{pf.min_version}})
      break;
{%-     endif %}
{%-     if kind|is_object_kind %}
{%-       if kind|is_union_kind %}
    Deserialize_(&{{input}}->{{name}}, &{{output_field}});
{%-       else %}
    Deserialize_({{input}}->{{name}}.ptr, &{{output_field}});
{%-       endif %}
{%-     elif kind|is_interface_kind %}
    mojo::internal::InterfaceDataToPointer(&{{input}}->{{name}}, &{{output_field}});
{%-     elif kind|is_interface_request_kind %}
    {{output_field}}.Bind(mojo::MakeScopedHandle(mojo::internal::FetchAndReset(&{{input}}->{{name}})));
{%-     elif kind|is_any_handle_kind %}
    {{output_field}}.reset(mojo::internal::FetchAndReset(&{{input}}->{{name}}));
{%-     elif kind|is_enum_kind %}
    {{output_field}} = static_cast<{{kind|cpp_wrapper_type}}>({{input}}->{{name}});
{%-     else %}
    {{output_field}} = {{input}}->{{name}};
{%-     endif %}
{%-   endfor %}
  } while (false);
{%- endmacro %}