Problem: message_t ctor for ranges too greedy

Solution: Detect ranges with enable_if idiom
This commit is contained in:
Gudmundur Adalsteinsson
2019-05-15 16:49:22 +00:00
parent d25c58a05d
commit 09ab20801a
3 changed files with 57 additions and 5 deletions

43
zmq.hpp
View File

@@ -152,6 +152,39 @@ typedef struct
namespace zmq
{
#ifdef ZMQ_CPP11
namespace detail
{
template<class T> using void_t = void;
template<class Iter>
using iter_value_t = typename std::iterator_traits<Iter>::value_type;
template<class Range>
using range_iter_t = decltype(
std::begin(std::declval<typename std::remove_reference<Range>::type &>()));
template<class Range>
using range_value_t = iter_value_t<range_iter_t<Range>>;
template<class T, class = void> struct is_range : std::false_type
{
};
template<class T>
struct is_range<
T,
void_t<decltype(
std::begin(std::declval<typename std::remove_reference<T>::type &>())
== std::end(std::declval<typename std::remove_reference<T>::type &>()))>>
: std::true_type
{
};
} // namespace detail
#endif
typedef zmq_free_fn free_fn;
typedef zmq_pollitem_t pollitem_t;
@@ -278,10 +311,12 @@ class message_t
}
#if defined(ZMQ_BUILD_DRAFT_API) && defined(ZMQ_CPP11)
// TODO: this function is too greedy, must add
// SFINAE for begin and end support.
template<typename T>
explicit message_t(const T &msg_) : message_t(std::begin(msg_), std::end(msg_))
template<class Range,
typename = typename std::enable_if<
detail::is_range<Range>::value
&& std::is_trivially_copyable<detail::range_value_t<Range>>::value
&& !std::is_same<Range, message_t>::value>::type>
explicit message_t(const Range &rng) : message_t(std::begin(rng), std::end(rng))
{
}
#endif