/*
- * Copyright 2013 Facebook, Inc.
+ * Copyright 2016 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
// @author: Andrei Alexandrescu
-#ifndef FOLLY_BASE_TRAITS_H_
-#define FOLLY_BASE_TRAITS_H_
+#pragma once
#include <memory>
+#include <limits>
#include <type_traits>
-
+#include <functional>
+
+#include <folly/Portability.h>
+
+// libc++ doesn't provide this header, nor does msvc
+#ifdef FOLLY_HAVE_BITS_CXXCONFIG_H
+// This file appears in two locations: inside fbcode and in the
+// libstdc++ source code (when embedding fbstring as std::string).
+// To aid in this schizophrenic use, two macros are defined in
+// c++config.h:
+// _LIBSTDCXX_FBSTRING - Set inside libstdc++. This is useful to
+// gate use inside fbcode v. libstdc++
#include <bits/c++config.h>
+#endif
#include <boost/type_traits.hpp>
-#include <boost/mpl/and.hpp>
#include <boost/mpl/has_xxx.hpp>
-#include <boost/mpl/not.hpp>
namespace folly {
traits_detail::has_true_IsZeroInitializable<T>::value
> {};
+template <typename...>
+struct Conjunction : std::true_type {};
+template <typename T>
+struct Conjunction<T> : T {};
+template <typename T, typename... TList>
+struct Conjunction<T, TList...>
+ : std::conditional<T::value, Conjunction<TList...>, T>::type {};
+
+template <typename...>
+struct Disjunction : std::false_type {};
+template <typename T>
+struct Disjunction<T> : T {};
+template <typename T, typename... TList>
+struct Disjunction<T, TList...>
+ : std::conditional<T::value, T, Disjunction<TList...>>::type {};
+
+template <typename T>
+struct Negation : std::integral_constant<bool, !T::value> {};
+
} // namespace folly
/**
* although that is not guaranteed by the standard.
*/
-namespace std {
+FOLLY_NAMESPACE_STD_BEGIN
template <class T, class U>
struct pair;
#ifndef _GLIBCXX_USE_FB
+FOLLY_GLIBCXX_NAMESPACE_CXX11_BEGIN
template <class T, class R, class A>
class basic_string;
+FOLLY_GLIBCXX_NAMESPACE_CXX11_END
#else
template <class T, class R, class A, class S>
class basic_string;
class vector;
template <class T, class A>
class deque;
+FOLLY_GLIBCXX_NAMESPACE_CXX11_BEGIN
template <class T, class A>
class list;
+FOLLY_GLIBCXX_NAMESPACE_CXX11_END
template <class T, class C, class A>
class set;
template <class K, class V, class C, class A>
template <class T>
class shared_ptr;
-}
+FOLLY_NAMESPACE_STD_END
namespace boost {
template <class T, class U>
struct has_nothrow_constructor< std::pair<T, U> >
- : ::boost::mpl::and_< has_nothrow_constructor<T>,
- has_nothrow_constructor<U> > {};
+ : std::integral_constant<bool,
+ has_nothrow_constructor<T>::value &&
+ has_nothrow_constructor<U>::value> {};
} // namespace boost
// STL commonly-used types
template <class T, class U>
-struct IsRelocatable< std::pair<T, U> >
- : ::boost::mpl::and_< IsRelocatable<T>, IsRelocatable<U> > {};
+struct IsRelocatable< std::pair<T, U> >
+ : std::integral_constant<bool,
+ IsRelocatable<T>::value &&
+ IsRelocatable<U>::value> {};
// Is T one of T1, T2, ..., Tn?
template <class T, class... Ts>
};
/*
- * Complementary type traits to check for a negative value.
+ * Complementary type traits for integral comparisons.
+ *
+ * For instance, `if(x < 0)` yields an error in clang for unsigned types
+ * when -Werror is used due to -Wtautological-compare
*
- * if(x < 0) yields an error in clang for unsigned types when -Werror is used
+ *
+ * @author: Marcelo Juchem <marcelo@fb.com>
*/
namespace detail {
template <typename T>
struct is_negative_impl<T, false> {
- constexpr static bool check(T x) { return false; }
+ constexpr static bool check(T) { return false; }
};
+// folly::to integral specializations can end up generating code
+// inside what are really static ifs (not executed because of the templated
+// types) that violate -Wsign-compare so suppress them in order to not prevent
+// all calling code from using it.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsign-compare"
+
+template <typename RHS, RHS rhs, typename LHS>
+bool less_than_impl(LHS const lhs) {
+ return
+ rhs > std::numeric_limits<LHS>::max() ? true :
+ rhs <= std::numeric_limits<LHS>::min() ? false :
+ lhs < rhs;
+}
+
+#pragma GCC diagnostic pop
+
+template <typename RHS, RHS rhs, typename LHS>
+bool greater_than_impl(LHS const lhs) {
+ return
+ rhs > std::numeric_limits<LHS>::max() ? false :
+ rhs < std::numeric_limits<LHS>::min() ? true :
+ lhs > rhs;
+}
+
} // namespace detail {
+// same as `x < 0`
template <typename T>
constexpr bool is_negative(T x) {
return folly::detail::is_negative_impl<T, std::is_signed<T>::value>::check(x);
}
+// same as `x <= 0`
+template <typename T>
+constexpr bool is_non_positive(T x) { return !x || folly::is_negative(x); }
+
+// same as `x > 0`
+template <typename T>
+constexpr bool is_positive(T x) { return !is_non_positive(x); }
+
+// same as `x >= 0`
+template <typename T>
+constexpr bool is_non_negative(T x) {
+ return !x || is_positive(x);
+}
+
+template <typename RHS, RHS rhs, typename LHS>
+bool less_than(LHS const lhs) {
+ return detail::less_than_impl<
+ RHS, rhs, typename std::remove_reference<LHS>::type
+ >(lhs);
+}
+
+template <typename RHS, RHS rhs, typename LHS>
+bool greater_than(LHS const lhs) {
+ return detail::greater_than_impl<
+ RHS, rhs, typename std::remove_reference<LHS>::type
+ >(lhs);
+}
+
+/**
+ * Like std::piecewise_construct, a tag type & instance used for in-place
+ * construction of non-movable contained types, e.g. by Synchronized.
+ */
+struct construct_in_place_t {};
+constexpr construct_in_place_t construct_in_place{};
+
} // namespace folly
+// gcc-5.0 changed string's implementation in libgcc to be non-relocatable
+#if __GNUC__ < 5
FOLLY_ASSUME_FBVECTOR_COMPATIBLE_3(std::basic_string);
+#endif
FOLLY_ASSUME_FBVECTOR_COMPATIBLE_2(std::vector);
FOLLY_ASSUME_FBVECTOR_COMPATIBLE_2(std::list);
FOLLY_ASSUME_FBVECTOR_COMPATIBLE_2(std::deque);
-FOLLY_ASSUME_FBVECTOR_COMPATIBLE_4(std::map);
-FOLLY_ASSUME_FBVECTOR_COMPATIBLE_3(std::set);
FOLLY_ASSUME_FBVECTOR_COMPATIBLE_2(std::unique_ptr);
FOLLY_ASSUME_FBVECTOR_COMPATIBLE_1(std::shared_ptr);
FOLLY_ASSUME_FBVECTOR_COMPATIBLE_1(std::function);
// Boost
FOLLY_ASSUME_FBVECTOR_COMPATIBLE_1(boost::shared_ptr);
+#define FOLLY_CREATE_HAS_MEMBER_TYPE_TRAITS(classname, type_name) \
+ template <typename T> \
+ struct classname { \
+ template <typename C> \
+ constexpr static bool test(typename C::type_name*) { return true; } \
+ template <typename> \
+ constexpr static bool test(...) { return false; } \
+ constexpr static bool value = test<T>(nullptr); \
+ }
+
#define FOLLY_CREATE_HAS_MEMBER_FN_TRAITS_IMPL(classname, func_name, cv_qual) \
template <typename TTheClass_, typename RTheReturn_, typename... TTheArgs_> \
class classname<TTheClass_, RTheReturn_(TTheArgs_...) cv_qual> { \
* cout << "Does class Bar have a member double test(const string&, long)? "
* << boolalpha << has_test_traits<Bar, double(const string&, long)>::value;
* }
+ *
+ * @author: Marcelo Juchem <marcelo@fb.com>
*/
#define FOLLY_CREATE_HAS_MEMBER_FN_TRAITS(classname, func_name) \
template <typename, typename> class classname; \
FOLLY_CREATE_HAS_MEMBER_FN_TRAITS_IMPL(classname, func_name, ); \
FOLLY_CREATE_HAS_MEMBER_FN_TRAITS_IMPL(classname, func_name, const); \
- FOLLY_CREATE_HAS_MEMBER_FN_TRAITS_IMPL(classname, func_name, volatile); \
- FOLLY_CREATE_HAS_MEMBER_FN_TRAITS_IMPL(classname, func_name, volatile const)
-
-#endif //FOLLY_BASE_TRAITS_H_
+ FOLLY_CREATE_HAS_MEMBER_FN_TRAITS_IMPL( \
+ classname, func_name, /* nolint */ volatile); \
+ FOLLY_CREATE_HAS_MEMBER_FN_TRAITS_IMPL( \
+ classname, func_name, /* nolint */ volatile const)
projects / folly.git / blobdiff