mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-24 13:21:05 +00:00
13bfe75b97
Differential Revision: https://phabricator.services.mozilla.com/D68560 --HG-- extra : moz-landing-system : lando
108 lines
3.2 KiB
C++
108 lines
3.2 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/. */
|
|
|
|
/* Template-based metaprogramming and type-testing facilities. */
|
|
|
|
#ifndef mozilla_TypeTraits_h
|
|
#define mozilla_TypeTraits_h
|
|
|
|
#include "mozilla/Types.h"
|
|
|
|
#include <type_traits>
|
|
#include <utility>
|
|
|
|
/*
|
|
* These traits are approximate copies of the traits and semantics from C++11's
|
|
* <type_traits> header. Don't add traits not in that header! When all
|
|
* platforms provide that header, we can convert all users and remove this one.
|
|
*/
|
|
|
|
namespace mozilla {
|
|
|
|
/* 20.9.4 Unary type traits [meta.unary] */
|
|
|
|
/* 20.9.4.3 Type properties [meta.unary.prop] */
|
|
|
|
/**
|
|
* Traits class for identifying POD types. Until C++11 there's no automatic
|
|
* way to detect PODs, so for the moment this is done manually. Users may
|
|
* define specializations of this class that inherit from std::true_type and
|
|
* std::false_type (or equivalently std::integral_constant<bool, true or
|
|
* false>, or conveniently from mozilla::IsPod for composite types) as needed to
|
|
* ensure correct IsPod behavior.
|
|
*/
|
|
template <typename T>
|
|
struct IsPod : public std::false_type {};
|
|
|
|
template <>
|
|
struct IsPod<char> : std::true_type {};
|
|
template <>
|
|
struct IsPod<signed char> : std::true_type {};
|
|
template <>
|
|
struct IsPod<unsigned char> : std::true_type {};
|
|
template <>
|
|
struct IsPod<short> : std::true_type {};
|
|
template <>
|
|
struct IsPod<unsigned short> : std::true_type {};
|
|
template <>
|
|
struct IsPod<int> : std::true_type {};
|
|
template <>
|
|
struct IsPod<unsigned int> : std::true_type {};
|
|
template <>
|
|
struct IsPod<long> : std::true_type {};
|
|
template <>
|
|
struct IsPod<unsigned long> : std::true_type {};
|
|
template <>
|
|
struct IsPod<long long> : std::true_type {};
|
|
template <>
|
|
struct IsPod<unsigned long long> : std::true_type {};
|
|
template <>
|
|
struct IsPod<bool> : std::true_type {};
|
|
template <>
|
|
struct IsPod<float> : std::true_type {};
|
|
template <>
|
|
struct IsPod<double> : std::true_type {};
|
|
template <>
|
|
struct IsPod<wchar_t> : std::true_type {};
|
|
template <>
|
|
struct IsPod<char16_t> : std::true_type {};
|
|
template <typename T>
|
|
struct IsPod<T*> : std::true_type {};
|
|
|
|
namespace detail {
|
|
|
|
struct DoIsDestructibleImpl {
|
|
template <typename T, typename = decltype(std::declval<T&>().~T())>
|
|
static std::true_type test(int);
|
|
template <typename T>
|
|
static std::false_type test(...);
|
|
};
|
|
|
|
template <typename T>
|
|
struct IsDestructibleImpl : public DoIsDestructibleImpl {
|
|
typedef decltype(test<T>(0)) Type;
|
|
};
|
|
|
|
} // namespace detail
|
|
|
|
/**
|
|
* IsDestructible determines whether a type has a public destructor.
|
|
*
|
|
* struct S0 {}; // Implicit default destructor.
|
|
* struct S1 { ~S1(); };
|
|
* class C2 { ~C2(); }; // private destructor.
|
|
*
|
|
* mozilla::IsDestructible<S0>::value is true;
|
|
* mozilla::IsDestructible<S1>::value is true;
|
|
* mozilla::IsDestructible<C2>::value is false.
|
|
*/
|
|
template <typename T>
|
|
struct IsDestructible : public detail::IsDestructibleImpl<T>::Type {};
|
|
|
|
} /* namespace mozilla */
|
|
|
|
#endif /* mozilla_TypeTraits_h */
|