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QVariantIsNull: remove the non-C++11 implementation

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decltype is required now

Change-Id: I69173127bd35f1d29945c8cfa47e1fbf1479c14d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@theqtcompany.com>
This commit is contained in:
Olivier Goffart 2015-11-07 13:16:38 +01:00 committed by Olivier Goffart (Woboq GmbH)
parent ae35b2dc62
commit 6a2f7aa3ae
1 changed files with 0 additions and 39 deletions
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39
src/corelib/kernel/qvariant_p.h
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@ -202,7 +202,6 @@ class QVariantIsNull
/// \internal
/// This class checks if a type T has method called isNull. Result is kept in the Value property
/// TODO Can we somehow generalize it? A macro version?
#if defined(Q_COMPILER_DECLTYPE) // C++11 version
template<typename T>
class HasIsNullMethod {
struct Yes { char unused[1]; };
@ -214,44 +213,6 @@ class QVariantIsNull
public:
static const bool Value = (sizeof(test<T>(0)) == sizeof(Yes));
};
#elif defined(Q_CC_MSVC) && _MSC_VER >= 1400 && !defined(Q_CC_INTEL) // MSVC 2005, 2008 version: no decltype, but 'sealed' classes (>=2010 has decltype)
template<typename T>
class HasIsNullMethod {
struct Yes { char unused[1]; };
struct No { char unused[2]; };
Q_STATIC_ASSERT(sizeof(Yes) != sizeof(No));
template<class C> static Yes test(char (*)[(&C::isNull == 0) + 1]);
template<class C> static No test(...);
public:
static const bool Value = (sizeof(test<T>(0)) == sizeof(Yes));
};
#else // C++98 version (doesn't work for final classes)
template<typename T, bool IsClass = QTypeInfo<T>::isComplex>
class HasIsNullMethod
{
struct Yes { char unused[1]; };
struct No { char unused[2]; };
Q_STATIC_ASSERT(sizeof(Yes) != sizeof(No));
struct FallbackMixin { bool isNull() const; };
struct Derived : public T, public FallbackMixin {}; // <- doesn't work for final classes
template<class C, C> struct TypeCheck {};
template<class C> static Yes test(...);
template<class C> static No test(TypeCheck<bool (FallbackMixin::*)() const, &C::isNull> *);
public:
static const bool Value = (sizeof(test<Derived>(0)) == sizeof(Yes));
};
// We need to exclude primitive types as they won't compile with HasIsNullMethod::Check classes
// anyway it is not a problem as the types do not have isNull method.
template<typename T>
class HasIsNullMethod<T, /* IsClass = */ false> {
public:
static const bool Value = false;
};
#endif
// TODO This part should go to autotests during HasIsNullMethod generalization.
Q_STATIC_ASSERT(!HasIsNullMethod<bool>::Value);