gecko-dev/mfbt/Opaque.h
2020-03-28 13:57:15 +00:00

42 lines
1.1 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* An opaque integral type supporting only comparison operators. */
#ifndef mozilla_Opaque_h
#define mozilla_Opaque_h
#include <type_traits>
namespace mozilla {
/**
* Opaque<T> is a replacement for integral T in cases where only comparisons
* must be supported, and it's desirable to prevent accidental dependency on
* exact values.
*/
template <typename T>
class Opaque final {
static_assert(std::is_integral_v<T>,
"mozilla::Opaque only supports integral types");
T mValue;
public:
Opaque() = default;
explicit Opaque(T aValue) : mValue(aValue) {}
bool operator==(const Opaque& aOther) const {
return mValue == aOther.mValue;
}
bool operator!=(const Opaque& aOther) const { return !(*this == aOther); }
};
} // namespace mozilla
#endif /* mozilla_Opaque_h */