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

class {{struct.name}}DataView {
 public:
  {{struct.name}}DataView() {}

  {{struct.name}}DataView(
      internal::{{struct.name}}_Data* data,
      mojo::internal::SerializationContext* context)
{%- if struct|requires_context_for_data_view %}
      : data_(data), context_(context) {}
{%- else %}
      : data_(data) {}
{%- endif %}

  bool is_null() const { return !data_; }

{%- for pf in struct.packed.packed_fields_in_ordinal_order %}
{%-   set kind = pf.field.kind %}
{%-   set name = pf.field.name %}
{%-   if kind|is_union_kind %}
  inline void Get{{name|under_to_camel}}DataView(
      {{kind|cpp_data_view_type}}* output);

  template <typename UserType>
  WARN_UNUSED_RESULT bool Read{{name|under_to_camel}}(UserType* output) {
{%-     if pf.min_version != 0 %}
    auto* pointer = data_->header_.version >= {{pf.min_version}}
                    ? &data_->{{name}} : nullptr;
{%-     else %}
    auto* pointer = &data_->{{name}};
{%-     endif %}
    return mojo::internal::Deserialize<{{kind|unmapped_type_for_serializer}}>(
        pointer, output, context_);
  }

{%-   elif kind|is_object_kind %}
  inline void Get{{name|under_to_camel}}DataView(
      {{kind|cpp_data_view_type}}* output);

  template <typename UserType>
  WARN_UNUSED_RESULT bool Read{{name|under_to_camel}}(UserType* output) {
{%-     if pf.min_version != 0 %}
    auto* pointer = data_->header_.version >= {{pf.min_version}}
                    ? data_->{{name}}.Get() : nullptr;
{%-     else %}
    auto* pointer = data_->{{name}}.Get();
{%-     endif %}
    return mojo::internal::Deserialize<{{kind|unmapped_type_for_serializer}}>(
        pointer, output, context_);
  }

{%-   elif kind|is_enum_kind %}
  template <typename UserType>
  WARN_UNUSED_RESULT bool Read{{name|under_to_camel}}(UserType* output) const {
{%-     if pf.min_version != 0 %}
    auto data_value = data_->header_.version >= {{pf.min_version}}
                      ? data_->{{name}} : 0;
{%-     else %}
    auto data_value = data_->{{name}};
{%-     endif %}
    return mojo::internal::Deserialize<{{kind|unmapped_type_for_serializer}}>(
        data_value, output);
  }

  {{kind|cpp_data_view_type}} {{name}}() const {
{%-     if pf.min_version != 0 %}
    if (data_->header_.version < {{pf.min_version}})
      return {{kind|get_qualified_name_for_kind}}{};
{%-     endif %}
    return static_cast<{{kind|cpp_data_view_type}}>(data_->{{name}});
  }

{%-   elif kind|is_any_handle_kind %}
  {{kind|cpp_data_view_type}} Take{{name|under_to_camel}}() {
    {{kind|cpp_data_view_type}} result;
{%-     if pf.min_version != 0 %}
    if (data_->header_.version < {{pf.min_version}})
      return result;
{%-     endif %}
    bool ret =
        mojo::internal::Deserialize<{{kind|unmapped_type_for_serializer}}>(
            &data_->{{name}}, &result, context_);
    DCHECK(ret);
    return result;
  }

{%-   elif kind|is_any_interface_kind %}
  template <typename UserType>
  UserType Take{{name|under_to_camel}}() {
    UserType result;
{%-     if pf.min_version != 0 %}
    if (data_->header_.version < {{pf.min_version}})
      return result;
{%-     endif %}
    bool ret =
        mojo::internal::Deserialize<{{kind|unmapped_type_for_serializer}}>(
            &data_->{{name}}, &result, context_);
    DCHECK(ret);
    return result;
  }

{%-   else %}
  {{kind|cpp_data_view_type}} {{name}}() const {
{%-     if pf.min_version != 0 %}
    if (data_->header_.version < {{pf.min_version}})
      return {{kind|cpp_data_view_type}}{};
{%-     endif %}
    return data_->{{name}};
  }

{%-   endif %}
{%- endfor %}
 private:
  internal::{{struct.name}}_Data* data_ = nullptr;
{%- if struct|requires_context_for_data_view %}
  mojo::internal::SerializationContext* context_ = nullptr;
{%- endif %}
};