qt6-bb10/src/corelib/kernel/qwineventnotifier.cpp

244 lines
7.4 KiB
C++

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#include "qwineventnotifier.h"
#include "qeventdispatcher_win_p.h"
#include "qcoreapplication.h"
#include <private/qthread_p.h>
QT_BEGIN_NAMESPACE
class QWinEventNotifierPrivate : public QObjectPrivate
{
Q_DECLARE_PUBLIC(QWinEventNotifier)
public:
QWinEventNotifierPrivate()
: handleToEvent(0), enabled(false) {}
QWinEventNotifierPrivate(HANDLE h, bool e)
: handleToEvent(h), enabled(e) {}
HANDLE handleToEvent;
bool enabled;
};
/*!
\class QWinEventNotifier
\inmodule QtCore
\since 5.0
\brief The QWinEventNotifier class provides support for the Windows Wait functions.
The QWinEventNotifier class makes it possible to use the wait
functions on windows in a asynchronous manner. With this class,
you can register a HANDLE to an event and get notification when
that event becomes signalled. The state of the event is not modified
in the process so if it is a manual reset event you will need to
reset it after the notification.
Once you have created a event object using Windows API such as
CreateEvent() or OpenEvent(), you can create an event notifier to
monitor the event handle. If the event notifier is enabled, it will
emit the activated() signal whenever the corresponding event object
is signalled.
The setEnabled() function allows you to disable as well as enable the
event notifier. It is generally advisable to explicitly enable or
disable the event notifier. A disabled notifier does nothing when the
event object is signalled (the same effect as not creating the
event notifier). Use the isEnabled() function to determine the
notifier's current status.
Finally, you can use the setHandle() function to register a new event
object, and the handle() function to retrieve the event handle.
\b{Further information:}
Although the class is called QWinEventNotifier, it can be used for
certain other objects which are so-called synchronization
objects, such as Processes, Threads, Waitable timers.
\warning This class is only available on Windows.
*/
/*!
\fn void QWinEventNotifier::activated(HANDLE hEvent)
This signal is emitted whenever the event notifier is enabled and
the corresponding HANDLE is signalled.
The state of the event is not modified in the process, so if it is a
manual reset event, you will need to reset it after the notification.
The object is passed in the \a hEvent parameter.
\sa handle()
*/
/*!
Constructs an event notifier with the given \a parent.
*/
QWinEventNotifier::QWinEventNotifier(QObject *parent)
: QObject(*new QWinEventNotifierPrivate, parent)
{}
/*!
Constructs an event notifier with the given \a parent. It enables
the notifier, and watches for the event \a hEvent.
The notifier is enabled by default, i.e. it emits the activated() signal
whenever the corresponding event is signalled. However, it is generally
advisable to explicitly enable or disable the event notifier.
\sa setEnabled(), isEnabled()
*/
QWinEventNotifier::QWinEventNotifier(HANDLE hEvent, QObject *parent)
: QObject(*new QWinEventNotifierPrivate(hEvent, false), parent)
{
Q_D(QWinEventNotifier);
QAbstractEventDispatcher *eventDispatcher = d->threadData->eventDispatcher.load();
if (!eventDispatcher) {
qWarning("QWinEventNotifier: Can only be used with threads started with QThread");
} else {
eventDispatcher->registerEventNotifier(this);
}
d->enabled = true;
}
/*!
Destroys this notifier.
*/
QWinEventNotifier::~QWinEventNotifier()
{
setEnabled(false);
}
/*!
Register the HANDLE \a hEvent. The old HANDLE will be automatically
unregistered.
\b Note: The notifier will be disabled as a side effect and needs
to be re-enabled.
\sa handle(), setEnabled()
*/
void QWinEventNotifier::setHandle(HANDLE hEvent)
{
Q_D(QWinEventNotifier);
setEnabled(false);
d->handleToEvent = hEvent;
}
/*!
Returns the HANDLE that has been registered in the notifier.
\sa setHandle()
*/
HANDLE QWinEventNotifier::handle() const
{
Q_D(const QWinEventNotifier);
return d->handleToEvent;
}
/*!
Returns true if the notifier is enabled; otherwise returns false.
\sa setEnabled()
*/
bool QWinEventNotifier::isEnabled() const
{
Q_D(const QWinEventNotifier);
return d->enabled;
}
/*!
If \a enable is true, the notifier is enabled; otherwise the notifier
is disabled.
\sa isEnabled(), activated()
*/
void QWinEventNotifier::setEnabled(bool enable)
{
Q_D(QWinEventNotifier);
if (d->enabled == enable) // no change
return;
d->enabled = enable;
QAbstractEventDispatcher *eventDispatcher = d->threadData->eventDispatcher.load();
if (!eventDispatcher) // perhaps application is shutting down
return;
if (enable)
eventDispatcher->registerEventNotifier(this);
else
eventDispatcher->unregisterEventNotifier(this);
}
/*!
\reimp
*/
bool QWinEventNotifier::event(QEvent * e)
{
Q_D(QWinEventNotifier);
if (e->type() == QEvent::ThreadChange) {
if (d->enabled) {
QMetaObject::invokeMethod(this, "setEnabled", Qt::QueuedConnection,
Q_ARG(bool, true));
setEnabled(false);
}
}
QObject::event(e); // will activate filters
if (e->type() == QEvent::WinEventAct) {
emit activated(d->handleToEvent, QPrivateSignal());
return true;
}
return false;
}
QT_END_NAMESPACE