From 5f8de423f190bbb79a62f804151bc24824fa32d8 Mon Sep 17 00:00:00 2001 From: "Matt A. Tobin" Date: Fri, 2 Feb 2018 04:16:08 -0500 Subject: Add m-esr52 at 52.6.0 --- mfbt/Opaque.h | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 mfbt/Opaque.h (limited to 'mfbt/Opaque.h') diff --git a/mfbt/Opaque.h b/mfbt/Opaque.h new file mode 100644 index 000000000..d7239ee7c --- /dev/null +++ b/mfbt/Opaque.h @@ -0,0 +1,44 @@ +/* -*- 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 "mozilla/TypeTraits.h" + +namespace mozilla { + +/** + * Opaque 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 +class Opaque final +{ + static_assert(mozilla::IsIntegral::value, + "mozilla::Opaque only supports integral types"); + + T mValue; + +public: + Opaque() {} + 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 */ -- cgit v1.2.3