Use QDebugStateSaver in example operator<<()

This makes sure that changes in the debug stream - like nospace() - do not "leak". Also use the example snippet in QDebugStateSaver documentation. Pick-to: 6.2 6.3 Change-Id: I934976d2c7c2335abfec68c763526a5cbb0e6f1e Reviewed-by: Jörg Bornemann <[email protected]>
wukh0312 · Mar 16, 2022 · 9f5f64e · 9f5f64e
1 parent 21bffee
commit 9f5f64e
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diff --git a/examples/corelib/tools/customtype/message.cpp b/examples/corelib/tools/customtype/message.cpp
@@ -60,14 +60,15 @@ Message::Message(const QString &body, const QStringList &headers)
 //! [custom type streaming operator]
 QDebug operator<<(QDebug dbg, const Message &message)
 {
+    QDebugStateSaver saver(dbg);
     QList<QStringView> pieces = message.body().split(u"\r\n", Qt::SkipEmptyParts);
     if (pieces.isEmpty())
         dbg.nospace() << "Message()";
     else if (pieces.size() == 1)
         dbg.nospace() << "Message(" << pieces.first() << ")";
     else
         dbg.nospace() << "Message(" << pieces.first() << " ...)";
-    return dbg.maybeSpace();
+    return dbg;
 }
 //! [custom type streaming operator]
 

diff --git a/src/corelib/io/qdebug.cpp b/src/corelib/io/qdebug.cpp
@@ -961,6 +961,10 @@ QDebug &QDebug::resetFormat()
     so that using << Qt::hex in a QDebug operator doesn't affect other QDebug
     operators.
 
+    QDebugStateSaver is typically used in the implementation of an operator<<() for debugging:
+
+    \snippet tools/customtype/message.cpp custom type streaming operator
+
     \since 5.1
 */