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

{#---
  Macro for enum definition, and the declaration of associated functions.
---#}

{%- macro enum_decl(enum) %}
{%-   set enum_name = enum|get_name_for_kind(flatten_nested_kind=True) %}
enum class {{enum_name}} : int32_t {
{%-   for field in enum.fields %}
{%-     if field.value %}
  {{field.name}} = {{field.value|expression_to_text}},
{%-     else %}
  {{field.name}},
{%-     endif %}
{%-   endfor %}
};

inline std::ostream& operator<<(std::ostream& os, {{enum_name}} value) {
{%- if enum.fields %}
  switch(value) {
{%-   for _, values in enum.fields|groupby('numeric_value') %}
    case {{enum_name}}::{{values[0].name}}:
      return os << "{{enum_name}}::
{%-     if values|length > 1 -%}
      {{'{'}}
{%-     endif -%}
      {{values|map(attribute='name')|join(', ')}}
{%-     if values|length > 1 -%}
      {{'}'}}
{%-     endif -%}
      ";
{%-   endfor %}
    default:
      return os << "Unknown {{enum_name}} value: " << static_cast<int32_t>(value);
  }
{%- else %}
  return os << "Unknown {{enum_name}} value: " << static_cast<int32_t>(value);
{%- endif %}
}

{#-   Returns true if the given enum value exists in this version of enum. #}
inline bool IsKnownEnumValue({{enum_name}} value) {
  return {{enum|get_name_for_kind(internal=True,
                                  flatten_nested_kind=True)}}::IsKnownValue(
      static_cast<int32_t>(value));
}
{%- endmacro %}

{%- macro enum_data_decl(enum) %}
{%-   set enum_name = enum|get_name_for_kind(flatten_nested_kind=True) %}
struct {{enum_name}}_Data {
 public:
  static bool constexpr kIsExtensible = {% if enum.extensible %}true{% else %}false{% endif %};

  static bool IsKnownValue(int32_t value) {
{%- if enum.fields %}
    switch (value) {
{%-   for enum_field in enum.fields|groupby('numeric_value') %}
      case {{enum_field[0]}}:
{%-   endfor %}
        return true;
    }
{%- endif %}
    return false;
  }

  static bool Validate(int32_t value,
                       mojo::internal::ValidationContext* validation_context) {
    if (kIsExtensible || IsKnownValue(value))
      return true;

    ReportValidationError(validation_context,
                          mojo::internal::VALIDATION_ERROR_UNKNOWN_ENUM_VALUE);
    return false;
  }
};
{%- endmacro %}

{%- macro enum_hash(enum) %}
{%-   set enum_name = enum|get_qualified_name_for_kind(
          flatten_nested_kind=True) %}
template <>
struct hash<{{enum_name}}>
    : public mojo::internal::EnumHashImpl<{{enum_name}}> {};
{%- endmacro %}

{%- macro enum_hash_blink(enum) %}
{%-   set enum_name = enum|get_qualified_name_for_kind(
          flatten_nested_kind=True, include_variant=False) %}
{%-   set hash_fn_name = enum|wtf_hash_fn_name_for_enum %}
{#    We need two unused enum values: #}
{%-   set empty_value = -1000000 %}
{%-   set deleted_value = -1000001 %}
{%-   set empty_value_unused = "false" if empty_value in enum|all_enum_values else "true" %}
{%-   set deleted_value_unused = "false" if empty_value in enum|all_enum_values else "true" %}
namespace WTF {
struct {{hash_fn_name}} {
  static unsigned hash(const {{enum_name}}& value) {
    typedef base::underlying_type<{{enum_name}}>::type utype;
    return DefaultHash<utype>::Hash().hash(static_cast<utype>(value));
  }
  static bool equal(const {{enum_name}}& left, const {{enum_name}}& right) {
    return left == right;
  }
  static const bool safeToCompareToEmptyOrDeleted = true;
};

template <>
struct DefaultHash<{{enum_name}}> {
  using Hash = {{hash_fn_name}};
};

template <>
struct HashTraits<{{enum_name}}>
    : public GenericHashTraits<{{enum_name}}> {
  static_assert({{empty_value_unused}},
                "{{empty_value}} is a reserved enum value");
  static_assert({{deleted_value_unused}},
                "{{deleted_value}} is a reserved enum value");
  static const bool hasIsEmptyValueFunction = true;
  static bool isEmptyValue(const {{enum_name}}& value) {
    return value == static_cast<{{enum_name}}>({{empty_value}});
  }
  static void constructDeletedValue({{enum_name}}& slot, bool) {
    slot = static_cast<{{enum_name}}>({{deleted_value}});
  }
  static bool isDeletedValue(const {{enum_name}}& value) {
    return value == static_cast<{{enum_name}}>({{deleted_value}});
  }
};
}  // namespace WTF
{%- endmacro %}