diff options
Diffstat (limited to 'third_party/chromium/base/template_util.h')
-rw-r--r-- | third_party/chromium/base/template_util.h | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/third_party/chromium/base/template_util.h b/third_party/chromium/base/template_util.h index 0c3cac2..158daf1 100644 --- a/third_party/chromium/base/template_util.h +++ b/third_party/chromium/base/template_util.h @@ -5,16 +5,66 @@ #ifndef BASE_TEMPLATE_UTIL_H_ #define BASE_TEMPLATE_UTIL_H_ +#include <iosfwd> #include <type_traits> +#include <utility> #include "build/build_config.h" +// This hacks around libstdc++ 4.6 missing stuff in type_traits, while we need +// to support it. +#define CR_GLIBCXX_4_7_0 20120322 +#define CR_GLIBCXX_4_5_4 20120702 +#define CR_GLIBCXX_4_6_4 20121127 +#if defined(__GLIBCXX__) && \ + (__GLIBCXX__ < CR_GLIBCXX_4_7_0 || __GLIBCXX__ == CR_GLIBCXX_4_5_4 || \ + __GLIBCXX__ == CR_GLIBCXX_4_6_4) +#define CR_USE_FALLBACKS_FOR_OLD_GLIBCXX +#endif + namespace base { template <class T> struct is_non_const_reference : std::false_type {}; template <class T> struct is_non_const_reference<T&> : std::true_type {}; template <class T> struct is_non_const_reference<const T&> : std::false_type {}; +namespace internal { +// Uses expression SFINAE to detect whether using operator<< would work. +template <typename T, typename = void> +struct SupportsOstreamOperator : std::false_type {}; +template <typename T> +struct SupportsOstreamOperator<T, + decltype(void(std::declval<std::ostream&>() + << std::declval<T>()))> + : std::true_type {}; + +} // namespace internal + +// underlying_type produces the integer type backing an enum type. +// TODO(crbug.com/554293): Remove this when all platforms have this in the std +// namespace. +#if defined(CR_USE_FALLBACKS_FOR_OLD_GLIBCXX) +template <typename T> +struct underlying_type { + using type = __underlying_type(T); +}; +#else +template <typename T> +using underlying_type = std::underlying_type<T>; +#endif + +// TODO(crbug.com/554293): Remove this when all platforms have this in the std +// namespace. +#if defined(CR_USE_FALLBACKS_FOR_OLD_GLIBCXX) +template <class T> +using is_trivially_destructible = std::has_trivial_destructor<T>; +#else +template <class T> +using is_trivially_destructible = std::is_trivially_destructible<T>; +#endif + } // namespace base +#undef CR_USE_FALLBACKS_FOR_OLD_GLIBCXX + #endif // BASE_TEMPLATE_UTIL_H_ |