diff options
Diffstat (limited to 'src/corelib/tools/qsharedpointer_impl.h')
| -rw-r--r-- | src/corelib/tools/qsharedpointer_impl.h | 51 |
1 files changed, 20 insertions, 31 deletions
diff --git a/src/corelib/tools/qsharedpointer_impl.h b/src/corelib/tools/qsharedpointer_impl.h index 198cc58c38..362d57fb9a 100644 --- a/src/corelib/tools/qsharedpointer_impl.h +++ b/src/corelib/tools/qsharedpointer_impl.h @@ -71,21 +71,6 @@ QT_END_NAMESPACE QT_BEGIN_NAMESPACE - -// Macro QSHAREDPOINTER_VERIFY_AUTO_CAST -// generates a compiler error if the following construct isn't valid: -// T *ptr1; -// X *ptr2 = ptr1; -// -#ifdef QT_NO_DEBUG -# define QSHAREDPOINTER_VERIFY_AUTO_CAST(T, X) qt_noop() -#else - -template<typename T> inline void qt_sharedpointer_cast_check(T *) { } -# define QSHAREDPOINTER_VERIFY_AUTO_CAST(T, X) \ - qt_sharedpointer_cast_check<T>(static_cast<X *>(0)) -#endif - // // forward declarations // @@ -299,6 +284,9 @@ template <class T> class QSharedPointer { typedef T *QSharedPointer:: *RestrictedBool; typedef QtSharedPointer::ExternalRefCountData Data; + template <typename X> + using IfCompatible = typename std::enable_if<std::is_convertible<X*, T*>::value, bool>::type; + public: typedef T Type; typedef T element_type; @@ -322,11 +310,11 @@ public: Q_DECL_CONSTEXPR QSharedPointer(std::nullptr_t) noexcept : value(nullptr), d(nullptr) { } - template <class X> + template <class X, IfCompatible<X> = true> inline explicit QSharedPointer(X *ptr) : value(ptr) // noexcept { internalConstruct(ptr, QtSharedPointer::NormalDeleter()); } - template <class X, typename Deleter> + template <class X, typename Deleter, IfCompatible<X> = true> inline QSharedPointer(X *ptr, Deleter deleter) : value(ptr) // throws { internalConstruct(ptr, deleter); } @@ -354,7 +342,7 @@ public: return *this; } - template <class X> + template <class X, IfCompatible<X> = true> QSharedPointer(QSharedPointer<X> &&other) noexcept : value(other.value), d(other.d) { @@ -362,7 +350,7 @@ public: other.value = nullptr; } - template <class X> + template <class X, IfCompatible<X> = true> QSharedPointer &operator=(QSharedPointer<X> &&other) noexcept { QSharedPointer moved(std::move(other)); @@ -370,11 +358,11 @@ public: return *this; } - template <class X> + template <class X, IfCompatible<X> = true> QSharedPointer(const QSharedPointer<X> &other) noexcept : value(other.value), d(other.d) { if (d) ref(); } - template <class X> + template <class X, IfCompatible<X> = true> inline QSharedPointer &operator=(const QSharedPointer<X> &other) { QSharedPointer copy(other); @@ -382,11 +370,11 @@ public: return *this; } - template <class X> + template <class X, IfCompatible<X> = true> inline QSharedPointer(const QWeakPointer<X> &other) : value(nullptr), d(nullptr) { *this = other; } - template <class X> + template <class X, IfCompatible<X> = true> inline QSharedPointer<T> &operator=(const QWeakPointer<X> &other) { internalSet(other.d, other.value); return *this; } @@ -556,6 +544,8 @@ class QWeakPointer { typedef T *QWeakPointer:: *RestrictedBool; typedef QtSharedPointer::ExternalRefCountData Data; + template <typename X> + using IfCompatible = typename std::enable_if<std::is_convertible<X*, T*>::value, bool>::type; public: typedef T element_type; @@ -581,14 +571,14 @@ public: #ifndef QT_NO_QOBJECT // special constructor that is enabled only if X derives from QObject #if QT_DEPRECATED_SINCE(5, 0) - template <class X> + template <class X, IfCompatible<X> = true> QT_DEPRECATED inline QWeakPointer(X *ptr) : d(ptr ? Data::getAndRef(ptr) : nullptr), value(ptr) { } #endif #endif #if QT_DEPRECATED_SINCE(5, 0) - template <class X> + template <class X, IfCompatible<X> = true> QT_DEPRECATED inline QWeakPointer &operator=(X *ptr) { return *this = QWeakPointer(ptr); } #endif @@ -624,11 +614,11 @@ public: return *this; } - template <class X> + template <class X, IfCompatible<X> = true> inline QWeakPointer(const QWeakPointer<X> &o) : d(nullptr), value(nullptr) { *this = o; } - template <class X> + template <class X, IfCompatible<X> = true> inline QWeakPointer &operator=(const QWeakPointer<X> &o) { // conversion between X and T could require access to the virtual table @@ -645,14 +635,13 @@ public: bool operator!=(const QWeakPointer<X> &o) const noexcept { return !(*this == o); } - template <class X> + template <class X, IfCompatible<X> = true> inline QWeakPointer(const QSharedPointer<X> &o) : d(nullptr), value(nullptr) { *this = o; } - template <class X> + template <class X, IfCompatible<X> = true> inline QWeakPointer &operator=(const QSharedPointer<X> &o) { - QSHAREDPOINTER_VERIFY_AUTO_CAST(T, X); // if you get an error in this line, the cast is invalid internalSet(o.d, o.data()); return *this; } @@ -689,7 +678,7 @@ public: { return *this = QWeakPointer<X>(ptr, true); } #ifndef QT_NO_QOBJECT - template <class X> + template <class X, IfCompatible<X> = true> inline QWeakPointer(X *ptr, bool) : d(ptr ? Data::getAndRef(ptr) : nullptr), value(ptr) { } #endif |