------------------------------------------------------------
revno: 3141
committer: poy <p...@123gen.com>
branch nick: trunk
timestamp: Fri 2012-11-23 20:35:18 +0100
message:
sfinae fix for VS
modified:
dcpp/Util.h
test/testsfinae.cpp
--
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=== modified file 'dcpp/Util.h'
--- dcpp/Util.h 2012-11-10 15:15:22 +0000
+++ dcpp/Util.h 2012-11-23 19:35:18 +0000
@@ -92,29 +92,20 @@
template<typename T> double fraction(T a, T b) { return static_cast<double>(a) / b; }
/** Uses SFINAE to determine whether a type provides a function; stores the result in "value".
-Inspired by <http://stackoverflow.com/a/8752988>. */
-#ifndef _MSC_VER
-#define HAS_FUNC(name, funcRet, funcTest) \
- template<typename HAS_FUNC_T> struct name { \
- typedef char yes[1]; \
- typedef char no[2]; \
- template<typename HAS_FUNC_U> static yes& check(HAS_FUNC_U* data, \
- typename std::enable_if<std::is_same<funcRet, decltype(data->funcTest)>::value>::type* = nullptr); \
- template<typename> static no& check(...); \
- static const bool value = sizeof(check<HAS_FUNC_T>(nullptr)) == sizeof(yes); \
- }
-#else
-/// @todo don't verify the return type of the function on MSVC as it fails for obscure reasons. recheck later...
-#define HAS_FUNC(name, funcRet, funcTest) \
- template<typename HAS_FUNC_T> struct name { \
- typedef char yes[1]; \
- typedef char no[2]; \
- template<typename HAS_FUNC_U> static yes& check(HAS_FUNC_U* data, \
- decltype(data->funcTest)* = nullptr); \
- template<typename> static no& check(...); \
- static const bool value = sizeof(check<HAS_FUNC_T>(nullptr)) == sizeof(yes); \
- }
-#endif
+Inspired by <http://stackoverflow.com/a/8752988>.
+Note that checkRet & check could be merged into 1 function, but VS 11 doesn't like having a
+decltype inside that enable_if; so the 2 checks are separate. */
+#define HAS_FUNC(name, funcRet, funcTest) \
+ template<typename HAS_FUNC_T> struct name { \
+ typedef char yes[1]; \
+ typedef char no[2]; \
+ template<typename HAS_FUNC_V> static void checkRet( \
+ typename std::enable_if<std::is_same<funcRet, HAS_FUNC_V>::value>::type*); \
+ template<typename HAS_FUNC_U> static yes& check( \
+ decltype(checkRet<decltype(std::declval<HAS_FUNC_U>().funcTest)>(nullptr))*); \
+ template<typename> static no& check(...); \
+ static const bool value = sizeof(check<HAS_FUNC_T>(nullptr)) == sizeof(yes); \
+ }
class Util
{
=== modified file 'test/testsfinae.cpp'
--- test/testsfinae.cpp 2012-11-10 15:40:59 +0000
+++ test/testsfinae.cpp 2012-11-23 19:35:18 +0000
@@ -6,11 +6,16 @@
using namespace dcpp;
-struct Funcs {
+struct Base {
+ void fbase1() { }
+};
+
+struct Funcs : Base {
void f1() { }
void f2(int) { }
int f3() { return 0; }
void f4(const string&) { }
+ void f5(string&) { }
};
template<typename T>
@@ -20,6 +25,8 @@
HAS_FUNC(F2, void, f2(0));
HAS_FUNC(F3, int, f3());
HAS_FUNC(F4, void, f4(string()));
+ HAS_FUNC(F5, void, f5(std::function<string&()>()()));
+ HAS_FUNC(F6, void, fbase1());
// these should be false.
HAS_FUNC(FN1, void, lol());
@@ -30,6 +37,8 @@
bool test_F2() { return F2<T>::value; }
bool test_F3() { return F3<T>::value; }
bool test_F4() { return F4<T>::value; }
+ bool test_F5() { return F5<T>::value; }
+ bool test_F6() { return F6<T>::value; }
bool test_FN1() { return FN1<T>::value; }
bool test_FN2() { return FN2<T>::value; }
@@ -51,14 +60,12 @@
ASSERT_EQ(true, x.test_F2());
ASSERT_EQ(true, x.test_F3());
ASSERT_EQ(true, x.test_F4());
+ ASSERT_EQ(true, x.test_F5());
+ ASSERT_EQ(true, x.test_F6());
ASSERT_EQ(false, x.test_FN1());
-#ifndef _MSC_VER
- /* TODO these tests ensure that the return value of the tested function is correctly validated.
- doesn't work in MSVC, as explained by the definition of HAS_FUNC. */
ASSERT_EQ(false, x.test_FN2());
ASSERT_EQ(false, x.test_FN3());
-#endif
ASSERT_EQ(true, x.i());
}
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