Improved range detection supporting ADL

tests/CMakeLists.txt

@@ -25,7 +25,8 @@ add_executable(
     poller.cpp
     active_poller.cpp
     multipart.cpp
-	monitor.cpp
+    monitor.cpp
+    utilities.cpp
 )
 
 add_dependencies(unit_tests catch)

tests/message.cpp

@@ -13,17 +13,6 @@ static_assert(std::is_nothrow_swappable<zmq::message_t>::value,
               "message_t should be nothrow swappable");
 #endif
 
-#ifdef ZMQ_CPP11
-TEST_CASE("range SFINAE", "[message]")
-{
-    CHECK(!zmq::detail::is_range<int>::value);
-    CHECK(zmq::detail::is_range<std::string>::value);
-    CHECK(zmq::detail::is_range<std::string&>::value);
-    CHECK(zmq::detail::is_range<const std::string&>::value);
-    CHECK(zmq::detail::is_range<decltype("hello")>::value);
-}
-#endif
-
 TEST_CASE("message default constructed", "[message]")
 {
     const zmq::message_t message;

tests/utilities.cpp

@@ -0,0 +1,96 @@
+#include <catch.hpp>
+#include <zmq.hpp>
+
+#ifdef ZMQ_CPP11
+
+namespace test_ns
+{
+struct T_nr
+{
+};
+struct T_mr
+{
+    void *begin() const noexcept { return nullptr; }
+    void *end() const noexcept { return nullptr; }
+};
+struct T_fr
+{
+};
+void *begin(const T_fr &) noexcept
+{
+    return nullptr;
+}
+void *end(const T_fr &) noexcept
+{
+    return nullptr;
+}
+struct T_mfr
+{
+    void *begin() const noexcept { return nullptr; }
+    void *end() const noexcept { return nullptr; }
+};
+void *begin(const T_mfr &) noexcept
+{
+    return nullptr;
+}
+void *end(const T_mfr &) noexcept
+{
+    return nullptr;
+}
+
+// types with associated namespace std
+struct T_assoc_ns_nr : std::exception
+{
+};
+struct T_assoc_ns_mr : std::exception
+{
+    void *begin() const noexcept { return nullptr; }
+    void *end() const noexcept { return nullptr; }
+};
+struct T_assoc_ns_fr : std::exception
+{
+};
+void *begin(const T_assoc_ns_fr &) noexcept
+{
+    return nullptr;
+}
+void *end(const T_assoc_ns_fr &) noexcept
+{
+    return nullptr;
+}
+struct T_assoc_ns_mfr : std::exception
+{
+    void *begin() const noexcept { return nullptr; }
+    void *end() const noexcept { return nullptr; }
+};
+void *begin(const T_assoc_ns_mfr &) noexcept
+{
+    return nullptr;
+}
+void *end(const T_assoc_ns_mfr &) noexcept
+{
+    return nullptr;
+}
+} // namespace test_ns
+
+TEST_CASE("range SFINAE", "[utilities]")
+{
+    CHECK(!zmq::detail::is_range<int>::value);
+    CHECK(zmq::detail::is_range<std::string>::value);
+    CHECK(zmq::detail::is_range<std::string &>::value);
+    CHECK(zmq::detail::is_range<const std::string &>::value);
+    CHECK(zmq::detail::is_range<decltype("hello")>::value);
+    CHECK(zmq::detail::is_range<std::initializer_list<int>>::value);
+
+    CHECK(!zmq::detail::is_range<test_ns::T_nr>::value);
+    CHECK(zmq::detail::is_range<test_ns::T_mr>::value);
+    CHECK(zmq::detail::is_range<test_ns::T_fr>::value);
+    CHECK(zmq::detail::is_range<test_ns::T_mfr>::value);
+
+    CHECK(!zmq::detail::is_range<test_ns::T_assoc_ns_nr>::value);
+    CHECK(zmq::detail::is_range<test_ns::T_assoc_ns_mr>::value);
+    CHECK(zmq::detail::is_range<test_ns::T_assoc_ns_fr>::value);
+    CHECK(zmq::detail::is_range<test_ns::T_assoc_ns_mfr>::value);
+}
+
+#endif

zmq.hpp

@@ -156,14 +156,30 @@ namespace zmq
 #ifdef ZMQ_CPP11
 namespace detail
 {
+namespace ranges
+{
+using std::begin;
+using std::end;
+template<class T>
+auto begin(T&& r) -> decltype(begin(std::forward<T>(r)))
+{
+    return begin(std::forward<T>(r));
+}
+template<class T>
+auto end(T&& r) -> decltype(end(std::forward<T>(r)))
+{
+    return end(std::forward<T>(r));
+}
+} // namespace ranges
+
 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 &>()));
+  ranges::begin(std::declval<typename std::remove_reference<Range>::type &>()));
 
 template<class Range>
 using range_value_t = iter_value_t<range_iter_t<Range>>;
@@ -176,8 +192,8 @@ 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 &>()))>>
+    ranges::begin(std::declval<typename std::remove_reference<T>::type &>())
+    == ranges::end(std::declval<typename std::remove_reference<T>::type &>()))>>
     : std::true_type
 {
 };
@@ -316,7 +332,8 @@ class message_t
                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))
+    explicit message_t(const Range &rng) :
+        message_t(detail::ranges::begin(rng), detail::ranges::end(rng))
     {
     }
 #endif