blob: 383eb915931a5f46379bf5b43afe0ddb391dec07 [file] [log] [blame]
// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <type_traits>
namespace mojo {
namespace internal {
template <class T, T v>
struct IntegralConstant {
static const T value = v;
template <class T, T v>
const T IntegralConstant<T, v>::value;
typedef IntegralConstant<bool, true> TrueType;
typedef IntegralConstant<bool, false> FalseType;
template <class T>
struct IsConst : FalseType {};
template <class T>
struct IsConst<const T> : TrueType {};
template <class T>
struct IsPointer : FalseType {};
template <class T>
struct IsPointer<T*> : TrueType {};
template <bool B, typename T = void>
struct EnableIf {};
template <typename T>
struct EnableIf<true, T> {
typedef T type;
// Types YesType and NoType are guaranteed such that sizeof(YesType) <
// sizeof(NoType).
typedef char YesType;
struct NoType {
YesType dummy[2];
// A helper template to determine if given type is non-const move-only-type,
// i.e. if a value of the given type should be passed via std::move() in a
// destructive way.
template <typename T>
struct IsMoveOnlyType {
static const bool value = std::is_constructible<T, T&&>::value &&
!std::is_constructible<T, const T&>::value;
// This goop is a trick used to implement a template that can be used to
// determine if a given class is the base class of another given class.
template <typename, typename>
struct IsSame {
static bool const value = false;
template <typename A>
struct IsSame<A, A> {
static bool const value = true;
template <typename T>
struct EnsureTypeIsComplete {
// sizeof() cannot be applied to incomplete types, this line will fail
// compilation if T is forward declaration.
using CheckSize = char (*)[sizeof(T)];
template <typename Base, typename Derived>
struct IsBaseOf {
static Derived* CreateDerived();
static char(&Check(Base*))[1];
static char(&Check(...))[2];
EnsureTypeIsComplete<Base> check_base_;
EnsureTypeIsComplete<Derived> check_derived_;
static bool const value = sizeof Check(CreateDerived()) == 1 &&
!IsSame<Base const, void const>::value;
template <class T>
struct RemovePointer {
typedef T type;
template <class T>
struct RemovePointer<T*> {
typedef T type;
template <template <typename...> class Template, typename T>
struct IsSpecializationOf : FalseType {};
template <template <typename...> class Template, typename... Args>
struct IsSpecializationOf<Template, Template<Args...>> : TrueType {};
template <bool B, typename T, typename F>
struct Conditional {
typedef T type;
template <typename T, typename F>
struct Conditional<false, T, F> {
typedef F type;
template <typename T>
struct AlwaysFalse {
static const bool value = false;
} // namespace internal
} // namespace mojo