/*
* Copyright 2019 The Chromium Authors. All rights reserved.
* Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef RTC_BASE_STRONG_ALIAS_H_
#define RTC_BASE_STRONG_ALIAS_H_
#include <utility>
namespace webrtc {
// This is a copy of
// https://source.chromium.org/chromium/chromium/src/+/main:base/types/strong_alias.h
// as the API (and internals) are using type-safe integral identifiers, but this
// library can't depend on that file. The ostream operator has been removed
// per WebRTC library conventions, and the underlying type is exposed.
template <
typename TagType,
typename TheUnderlyingType>
class StrongAlias {
public:
using UnderlyingType = TheUnderlyingType;
constexpr StrongAlias() =
default;
constexpr explicit StrongAlias(
const UnderlyingType& v) : value_(v) {}
constexpr explicit StrongAlias(UnderlyingType&& v) noexcept
: value_(std::move(v)) {}
constexpr UnderlyingType*
operator->() {
return &value_; }
constexpr
const UnderlyingType*
operator->()
const {
return &value_; }
constexpr UnderlyingType&
operator*() & {
return value_; }
constexpr
const UnderlyingType&
operator*()
const& {
return value_; }
constexpr UnderlyingType&&
operator*() && {
return std::move(value_); }
constexpr
const UnderlyingType&&
operator*()
const&& {
return std::move(value_);
}
constexpr UnderlyingType& value() & {
return value_; }
constexpr
const UnderlyingType& value()
const& {
return value_; }
constexpr UnderlyingType&& value() && {
return std::move(value_); }
constexpr
const UnderlyingType&& value()
const&& {
return std::move(value_); }
constexpr explicit
operator const UnderlyingType&()
const& {
return value_; }
constexpr
bool operator==(
const StrongAlias& other)
const {
return value_ == other.value_;
}
constexpr
bool operator!=(
const StrongAlias& other)
const {
return value_ != other.value_;
}
constexpr
bool operator<(
const StrongAlias& other)
const {
return value_ < other.value_;
}
constexpr
bool operator<=(
const StrongAlias& other)
const {
return value_ <= other.value_;
}
constexpr
bool operator>(
const StrongAlias& other)
const {
return value_ > other.value_;
}
constexpr
bool operator>=(
const StrongAlias& other)
const {
return value_ >= other.value_;
}
protected:
UnderlyingType value_;
private:
// Helper function for using abseil hash types.
template <
typename H>
friend H AbslHashValue(H h,
const StrongAlias& st) {
return H::combine(std::move(h), st.value_);
}
};
}
// namespace webrtc
#endif // RTC_BASE_STRONG_ALIAS_H_
