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QDBusServiceWatcher: fix binding loops

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This class has two bindable properties - watchedServices and watchMode.
What makes this class non-trivial is the fact that these properties
depend on each other - setWatchedServices() need an up-to-date
watchMode to set up the services, and setWatchMode() needs an
up-to-date list of services in order to update the mode on them.

Update the setters in such way that they remove the bindings from
the updated property, and at the same time trigger the re-evaluation
of the property they depend on.
This includes refactoring of the helper setConnection() method in such
way that it does not cause property re-evaluation, and also update
of the {add,remove}Service() helper functions to take the watchMode as
an input parameter.

The public {add,remove}WatchedService() methods were updated similarly.
The logic of the removeWatchedService() method was additionally
updated to do some changes to the properties only if the
service-to-be-removed actually existed in the list.

Task-number: QTBUG-116346
Pick-to: 6.6 6.5
Change-Id: If46cf926c7ace9dc4893d8daaef088f61e41c21a
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>
This commit is contained in:
Ivan Solovev 2023-08-29 16:50:56 +02:00
parent 1ad424aed5
commit d85663ced8
1 changed files with 42 additions and 35 deletions
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77
src/dbus/qdbusservicewatcher.cpp
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@ -40,10 +40,11 @@ public:
&QDBusServiceWatcherPrivate::setWatchModeForwardToQ)
void _q_serviceOwnerChanged(const QString &, const QString &, const QString &);
void setConnection(const QStringList &services, const QDBusConnection &c, QDBusServiceWatcher::WatchMode watchMode);
void setConnection(const QStringList &newServices, const QDBusConnection &newConnection,
QDBusServiceWatcher::WatchMode newMode);
void addService(const QString &service);
void removeService(const QString &service);
void addService(const QString &service, QDBusServiceWatcher::WatchMode mode);
void removeService(const QString &service, QDBusServiceWatcher::WatchMode mode);
};
void QDBusServiceWatcherPrivate::_q_serviceOwnerChanged(const QString &service, const QString &oldOwner, const QString &newOwner)
@ -56,39 +57,43 @@ void QDBusServiceWatcherPrivate::_q_serviceOwnerChanged(const QString &service,
emit q->serviceUnregistered(service);
}
void QDBusServiceWatcherPrivate::setConnection(const QStringList &services,
const QDBusConnection &c,
QDBusServiceWatcher::WatchMode wm)
void QDBusServiceWatcherPrivate::setConnection(const QStringList &newServices,
const QDBusConnection &newConnection,
QDBusServiceWatcher::WatchMode newMode)
{
const QStringList oldServices = watchedServicesData.valueBypassingBindings();
const QDBusServiceWatcher::WatchMode oldMode = watchMode.valueBypassingBindings();
if (connection.isConnected()) {
// remove older rules
for (const QString &s : std::as_const(watchedServicesData.value()))
removeService(s);
for (const QString &s : oldServices)
removeService(s, oldMode);
}
connection = c;
watchMode.setValueBypassingBindings(wm); // caller has to call notify()
watchedServicesData.setValueBypassingBindings(services); // caller has to call notify()
connection = newConnection;
watchMode.setValueBypassingBindings(newMode); // caller has to call notify()
watchedServicesData.setValueBypassingBindings(newServices); // caller has to call notify()
if (connection.isConnected()) {
// add new rules
for (const QString &s : std::as_const(watchedServicesData.value()))
addService(s);
for (const QString &s : newServices)
addService(s, newMode);
}
}
void QDBusServiceWatcherPrivate::addService(const QString &service)
void QDBusServiceWatcherPrivate::addService(const QString &service,
QDBusServiceWatcher::WatchMode mode)
{
QDBusConnectionPrivate *d = QDBusConnectionPrivate::d(connection);
if (d && d->shouldWatchService(service))
d->watchService(service, watchMode, q_func(), SLOT(_q_serviceOwnerChanged(QString,QString,QString)));
d->watchService(service, mode, q_func(), SLOT(_q_serviceOwnerChanged(QString,QString,QString)));
}
void QDBusServiceWatcherPrivate::removeService(const QString &service)
void QDBusServiceWatcherPrivate::removeService(const QString &service,
QDBusServiceWatcher::WatchMode mode)
{
QDBusConnectionPrivate *d = QDBusConnectionPrivate::d(connection);
if (d && d->shouldWatchService(service))
d->unwatchService(service, watchMode, q_func(), SLOT(_q_serviceOwnerChanged(QString,QString,QString)));
d->unwatchService(service, mode, q_func(), SLOT(_q_serviceOwnerChanged(QString,QString,QString)));
}
/*!
@ -260,8 +265,9 @@ void QDBusServiceWatcher::setWatchedServices(const QStringList &services)
{
Q_D(QDBusServiceWatcher);
d->watchedServicesData.removeBindingUnlessInWrapper();
if (services == d->watchedServicesData)
if (services == d->watchedServicesData.valueBypassingBindings())
return;
// trigger watchMode re-evaluation, but only once for the setter
d->setConnection(services, d->connection, d->watchMode);
d->watchedServicesData.notify();
}
@ -283,13 +289,14 @@ void QDBusServiceWatcher::addWatchedService(const QString &newService)
{
Q_D(QDBusServiceWatcher);
d->watchedServicesData.removeBindingUnlessInWrapper();
if (d->watchedServicesData.value().contains(newService))
auto services = d->watchedServicesData.valueBypassingBindings();
if (services.contains(newService))
return;
d->addService(newService);
// re-evaluate watch mode
d->addService(newService, d->watchMode);
auto templist = d->watchedServicesData.valueBypassingBindings();
templist << newService;
d->watchedServicesData.setValueBypassingBindings(templist);
services << newService;
d->watchedServicesData.setValueBypassingBindings(services);
d->watchedServicesData.notify();
}
@ -308,17 +315,16 @@ bool QDBusServiceWatcher::removeWatchedService(const QString &service)
{
Q_D(QDBusServiceWatcher);
d->watchedServicesData.removeBindingUnlessInWrapper();
d->removeService(service);
auto tempList = d->watchedServicesData.value();
bool result = tempList.removeOne(service);
if (result) {
d->watchedServicesData.setValueBypassingBindings(tempList);
d->watchedServicesData.notify();
return true;
} else {
// nothing changed
return false;
}
auto tempList = d->watchedServicesData.valueBypassingBindings();
const bool result = tempList.removeOne(service);
if (!result)
return false; // nothing changed
// re-evaluate watch mode
d->removeService(service, d->watchMode);
d->watchedServicesData.setValueBypassingBindings(tempList);
d->watchedServicesData.notify();
return true;
}
QDBusServiceWatcher::WatchMode QDBusServiceWatcher::watchMode() const
@ -335,8 +341,9 @@ void QDBusServiceWatcher::setWatchMode(WatchMode mode)
{
Q_D(QDBusServiceWatcher);
d->watchMode.removeBindingUnlessInWrapper();
if (mode == d->watchMode.value())
if (mode == d->watchMode.valueBypassingBindings())
return;
// trigger watchedServicesData re-evaluation, but only once for the setter
d->setConnection(d->watchedServicesData, d->connection, mode);
d->watchMode.notify();
}