JSON, unlike, say, QDataStream, allows building up objects independent
of some central object, and combining them into a QJsonDocument
later. This suggests returning QJsonObjects from a toJson() const
method instead of having the caller supply a QJsonObject. Doing it
this way enables transparent move semantics to kick in, too.
For deserialization, use a fromJson() named constructor for value-like
classes (where identity doesn't matter, only equality). Keep using
read(), too, and add a note to explain when to use which form.
Also, avoid the triple lookup from
if (json.contains("key") && json["key"].isSoughtType())
mFoo = json["key"].toSoughtType();
by using C++17 if-with-initializer and showing the trick with
Undefined never being of isSoughtType():
if (const QJsonValue v = json["key"]; v.isSoughtType())
mFoo = v.toSoughtType();
Adjust the discussion to match the new code, up the copyright years
and rename some qdoc snippet markers from nondescript [0]/[1] to
[toJson]/[fromJson].
Task-number: QTBUG-108857
Pick-to: 6.5 6.4 6.2
Change-Id: Icaa14acc7464fef00a59534679d710252e921383
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
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