mojo/public/tools/bindings/generators/dart_templates/union_definition.tmpl

{#--- Begin #}

{%- import "encoding_macros.tmpl" as encoding_macros %}

{%- macro enum_def(union) %}
enum {{union|name}}Tag {
{%-   for field in union.fields %}
  {{field|tag_name}},
{%-   endfor %}
  unknown
}
{%- endmacro %}

{%- macro wrapper_def(union) %}
class {{union|name}} extends bindings.Union {
  static final _tag_to_int = const {
{%-   for field in union.fields %}
    {{union|name}}Tag.{{field|tag_name}}: {{field.ordinal}},
{%-   endfor %}
  };

  static final _int_to_tag = const {
{%-   for field in union.fields %}
    {{field.ordinal}}: {{union|name}}Tag.{{field|tag_name}},
{%-   endfor %}
  };

  var _data;
  {{union|name}}Tag _tag = {{union|name}}Tag.unknown;

  {{union|name}}Tag get tag => _tag;

{%-   for field in union.fields %}
  {{field.kind|dart_type}} get {{field|name}} {
    if (_tag != {{union|name}}Tag.{{field|tag_name}}) {
      throw new bindings.UnsetUnionTagError(_tag, {{union|name}}Tag.{{field|tag_name}});
    }
    return _data;
  }

  set {{field|name}}({{field.kind|dart_type}} value) {
    _tag = {{union|name}}Tag.{{field|tag_name}};
    _data = value;
  }
{%-   endfor %}

  static {{union|name}} decode(bindings.Decoder decoder0, int offset) {
    int size = decoder0.decodeUint32(offset);
    if (size == 0) {
      return null;
    }
    {{union|name}} result = new {{union|name}}();

    // TODO(azani): Handle unknown union member.
    {{union|name}}Tag tag = _int_to_tag[decoder0.decodeUint32(offset + 4)];
    switch (tag) {
{%-   for field in union.fields %}
      case {{union|name}}Tag.{{field|tag_name}}:
{%-     if field.kind|is_union_kind %}
        var decoder1 = decoder0.decodePointer(offset + 8, {{field.kind|is_nullable_kind|dart_true_false}});
        result.{{field|name}} = {{field.kind|dart_type}}.decode(decoder1, 0);
{%-     else %}
        {{encoding_macros.decode('result.' ~ field|name, field.kind, "offset + 8", 0)|indent(8)}}
{%-     endif %}
        break;
{%-   endfor %}
    }

    return result;
  }

  void encode(bindings.Encoder encoder0, int offset) {
    // TODO(azani): Error when trying to encode an unknown member.
    encoder0.encodeUint32(16, offset);
    encoder0.encodeUint32(_tag_to_int[_tag], offset + 4);
    switch (_tag) {
{%-   for field in union.fields %}
      case {{union|name}}Tag.{{field|tag_name}}:
{%-     if field.kind|is_union_kind %}
        encoder0.encodeNestedUnion({{field|name}}, offset + 8, {{field.kind|is_nullable_kind|dart_true_false}});
{%-     else %}
        {{encoding_macros.encode(field|name, field.kind, "offset + 8", 0)|indent(8)}}
{%-     endif %}
        break;
{%-   endfor %}
    }
  }

  String toString() {
    String result = "{{union|name}}(";
    switch (_tag) {
{%-   for field in union.fields %}
      case {{union|name}}Tag.{{field|tag_name}}:
        result += "{{field|name}}";
        break;
{%-   endfor %}
      default:
        result += "unknown";
    }
    result += ": $_data)";
    return result;
  }
}
{%- endmacro %}


{%- macro union_def(union) %}
{{enum_def(union)}}
{{wrapper_def(union)}}
{%- endmacro %}