QDebug: add nothrow move special member functions

This requires making QDebugStateSaver hold QDebug::Stream directly, not
QDebug by reference, as the referenced object will have been moved from
when ~QDebugStateSaver executes. The stream object, however, will still
be around.

Change-Id: I0ca2eb60cb9b68ea3835d9a9ff5e295d9b1c5fb5
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: David Faure <david.faure@kdab.com>
 
 
 
 
 
 
 
 

1 files changed, 5 insertions, 4 deletions

diff --git a/src/corelib/io/qdebug.h b/src/corelib/io/qdebug.h
index 889fb6b571..421c5d933b 100644
--- a/src/corelib/io/qdebug.h
+++ b/src/corelib/io/qdebug.h
@@ -65,6 +65,7 @@ QT_BEGIN_NAMESPACE
 class Q_CORE_EXPORT QDebug
 {
     friend class QMessageLogger;
+    friend class QDebugStateSaver;
     friend class QDebugStateSaverPrivate;
     struct Stream {
         enum { VerbosityShift = 29, VerbosityMask = 0x7 };
@@ -114,7 +115,10 @@ public:
     inline QDebug(QString *string) : stream(new Stream(string)) {}
     inline QDebug(QtMsgType t) : stream(new Stream(t)) {}
     inline QDebug(const QDebug &o):stream(o.stream) { ++stream->ref; }
+    QDebug(QDebug &&other) noexcept : stream{qExchange(other.stream, nullptr)} {}
     inline QDebug &operator=(const QDebug &other);
+    QDebug &operator=(QDebug &&other) noexcept
+    { QDebug{std::move(other)}.swap(*this); return *this; }
     ~QDebug();
     inline void swap(QDebug &other) noexcept { qSwap(stream, other.stream); }
 
@@ -203,10 +207,7 @@ public:
 
 inline QDebug &QDebug::operator=(const QDebug &other)
 {
-    if (this != &other) {
-        QDebug copy(other);
-        qSwap(stream, copy.stream);
-    }
+    QDebug{other}.swap(*this);
     return *this;
 }