chromium/mojo/public/cpp/bindings/enum_utils.h

// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MOJO_PUBLIC_CPP_BINDINGS_ENUM_UTILS_H_
#define MOJO_PUBLIC_CPP_BINDINGS_ENUM_UTILS_H_

#include <optional>
#include <type_traits>

#include "base/numerics/safe_conversions.h"

namespace mojo {

// Converts |int_value| to |TMojoEnum|.  If |int_value| represents a known enum
// value, then a corresponding |TMojoEnum| value will be returned.  Returns
// |std::nullopt| otherwise.
//
// Using base::StrictNumeric as the parameter type prevents callers from
// accidentally using an implicit narrowing conversion when calling this
// function (e.g. calling it with an int64_t argument, when the enum's
// underlying type is int32_t).
template <typename TMojoEnum>
std::optional<TMojoEnum> ConvertIntToMojoEnum(
    base::StrictNumeric<int32_t> int_value) { … }

}  // namespace mojo

#endif  // MOJO_PUBLIC_CPP_BINDINGS_ENUM_UTILS_H_