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Diffstat (limited to 'mojo/public/cpp/bindings/lib/template_util.h')
-rw-r--r-- | mojo/public/cpp/bindings/lib/template_util.h | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/mojo/public/cpp/bindings/lib/template_util.h b/mojo/public/cpp/bindings/lib/template_util.h new file mode 100644 index 0000000000..5151123ac0 --- /dev/null +++ b/mojo/public/cpp/bindings/lib/template_util.h @@ -0,0 +1,120 @@ +// 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. + +#ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_TEMPLATE_UTIL_H_ +#define MOJO_PUBLIC_CPP_BINDINGS_LIB_TEMPLATE_UTIL_H_ + +#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 { + private: + static Derived* CreateDerived(); + static char(&Check(Base*))[1]; + static char(&Check(...))[2]; + + EnsureTypeIsComplete<Base> check_base_; + EnsureTypeIsComplete<Derived> check_derived_; + + public: + 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; +}; + +} // namespace internal +} // namespace mojo + +#endif // MOJO_PUBLIC_CPP_BINDINGS_LIB_TEMPLATE_UTIL_H_ |