QTaggedPointer: some API cleanups

- don't refer to the class with template arguments in the body of the class
  (incl. one where we got the template args wrong)
- make namespace-level swap a non-member friend
- make default ctor constexpr and non-explicit
  (default ctors should never be explicit)
- make ctor from std::nullptr_t constexpr
- remove op= from std::nullptr (will be handled by op=(T*) anyway)
- pass QTaggedPointer by value (it's a Trivial Type, so can be passed in registers)
- fix missing QTypeInfo for non-default Tag types
- remove unused include limits.h
- make qHash-able (why is the tag ignored?)

Change-Id: Idee1d685ac365c988698a8637fd5df3accfc1396
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 24 insertions, 6 deletions

diff --git a/src/corelib/tools/qtaggedpointer.qdoc b/src/corelib/tools/qtaggedpointer.qdoc
index 5b335e8739..303b89232c 100644
--- a/src/corelib/tools/qtaggedpointer.qdoc
+++ b/src/corelib/tools/qtaggedpointer.qdoc
@@ -93,6 +93,18 @@
 
 
 /*!
+    \fn template <typename T, typename Tag> QTaggedPointer<T, Tag>::QTaggedPointer()
+
+    Creates a tagged pointer that contains nullptr and stores no tag.
+*/
+
+/*!
+    \fn template <typename T, typename Tag> QTaggedPointer<T, Tag>::QTaggedPointer(std::nullptr_t)
+
+    Creates a tagged pointer that contains nullptr and stores no tag.
+*/
+
+/*!
     \fn template <typename T, typename Tag> explicit QTaggedPointer<T, Tag>::QTaggedPointer(T *pointer = nullptr, Tag tag = Tag()) noexcept
 
     Creates a tagged pointer that points to \a pointer and stores the specified \a tag.
@@ -159,7 +171,7 @@
 */
 
 /*!
-    \fn template <typename T, typename Tag> inline bool operator==(const QTaggedPointer<T, Tag> &lhs, const QTaggedPointer<T, Tag> &rhs) noexcept
+    \fn template <typename T, typename Tag> inline bool operator==(QTaggedPointer lhs, QTaggedPointer rhs) noexcept
     \relates QTaggedPointer
 
     Returns \c true if \a lhs is equal to \a rhs; otherwise returns \c false.
@@ -168,7 +180,7 @@
 */
 
 /*!
-    \fn template <typename T, typename Tag> inline bool operator!=(const QTaggedPointer<T, Tag> &lhs, const QTaggedPointer<T, Tag> &rhs) noexcept
+    \fn template <typename T, typename Tag> inline bool operator!=(QTaggedPointer lhs, QTaggedPointer rhs) noexcept
     \relates QTaggedPointer
 
     Returns \c true if \a lhs is not equal to \a rhs; otherwise returns \c false.
@@ -177,30 +189,36 @@
 */
 
 /*!
-    \fn template <typename T, typename Tag> inline bool operator==(const QTaggedPointer<T, Tag> &lhs, std::nullptr_t) noexcept
+    \fn template <typename T, typename Tag> inline bool operator==(QTaggedPointer lhs, std::nullptr_t) noexcept
     \relates QTaggedPointer
 
     Returns \c true if \a lhs refers to \c nullptr.
 */
 
 /*!
-    \fn template <typename T, typename Tag> inline bool operator==(std::nullptr_t, const QTaggedPointer<T, Tag> &rhs) noexcept
+    \fn template <typename T, typename Tag> inline bool operator==(std::nullptr_t, QTaggedPointer rhs) noexcept
     \relates QTaggedPointer
 
     Returns \c true if \a rhs refers to \c nullptr.
 */
 
 /*!
-    \fn template <typename T, typename Tag> inline bool operator!=(const QTaggedPointer<T, Tag> &lhs, std::nullptr_t) noexcept
+    \fn template <typename T, typename Tag> inline bool operator!=(QTaggedPointerlhs, std::nullptr_t) noexcept
     \relates QTaggedPointer
 
     Returns \c true if \a lhs refers to a valid (i.e. non-null) pointer.
 */
 
 /*!
-    \fn template <typename T, typename Tag> inline bool operator!=(std::nullptr_t, const QTaggedPointer<T, Tag> &rhs) noexcept
+    \fn template <typename T, typename Tag> inline bool operator!=(std::nullptr_t, QTaggedPointer rhs) noexcept
     \relates QTaggedPointer
 
     Returns \c true if \a rhs refers to a valid (i.e. non-null) pointer.
 */
 
+/*!
+    \fn template <typename T, typename Tag> qHash(QTaggedPointer<T, Tag> key, std::size_t seed)
+    \relates QTaggedPointer
+
+    Returns the hash value for the \a key, using \a seed to seed the calculation.
+*/