QJson*: value semantics cleanup

Re-add the move operations, add a swap(), mark as shared
(we're already using them in containers).

QJsonValue is slightly tricky, because it has an anonymous union,
which can't be easily moved in C++. Use the implementation of
the copy constructor as inspiration for the move.

[ChangeLog][QtCore][JSON] QJsonArray, QJsonDocument, QJsonObject
and QJsonValue now have move operations and a swap() member function.

Change-Id: Idfb94a93370ace96100efbd6559ef05b4c5adc39
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/src/corelib/json/qjsonarray.cpp b/src/corelib/json/qjsonarray.cpp
index d4cc4b81df..c5a5aaf39d 100644
--- a/src/corelib/json/qjsonarray.cpp
+++ b/src/corelib/json/qjsonarray.cpp
@@ -212,6 +212,27 @@ QJsonArray &QJsonArray::operator =(const QJsonArray &other)
     return *this;
 }
 
+/*!
+    \fn QJsonArray::QJsonArray(QJsonArray &&other)
+    \since 5.10
+
+    Move-constructs a QJsonArray from \a other.
+*/
+
+/*!
+    \fn QJsonArray &QJsonArray::operator =(QJsonArray &&other)
+    \since 5.10
+
+    Move-assigns \a other to this array.
+*/
+
+/*!
+    \fn void QJsonArray::swap(QJsonArray &other)
+    \since 5.10
+
+    Swaps the array \a other with this. This operation is very fast and never fails.
+*/
+
 /*! \fn QJsonArray &QJsonArray::operator+=(const QJsonValue &value)
 
     Appends \a value to the array, and returns a reference to the array itself.