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39
40#ifndef QTESTSUPPORT_CORE_H
41#define QTESTSUPPORT_CORE_H
42
43#include <QtCore/qcoreapplication.h>
44#include <QtCore/qdeadlinetimer.h>
45
46QT_BEGIN_NAMESPACE
47
48namespace QTestPrivate {
49Q_CORE_EXPORT void qSleep(int ms);
50}
51
52namespace QTest {
53
54template <typename Functor>
55Q_REQUIRED_RESULT static bool qWaitFor(Functor predicate, int timeout = 5000)
56{
57 // We should not spin the event loop in case the predicate is already true,
58 // otherwise we might send new events that invalidate the predicate.
59 if (predicate())
60 return true;
61
62 // qWait() is expected to spin the event loop, even when called with a small
63 // timeout like 1ms, so we we can't use a simple while-loop here based on
64 // the deadline timer not having timed out. Use do-while instead.
65
66 int remaining = timeout;
67 QDeadlineTimer deadline(remaining, Qt::PreciseTimer);
68
69 do {
70 // We explicitly do not pass the remaining time to processEvents, as
71 // that would keep spinning processEvents for the whole duration if
72 // new events were posted as part of processing events, and we need
73 // to return back to this function to check the predicate between
74 // each pass of processEvents. Our own timer will take care of the
75 // timeout.
76 QCoreApplication::processEvents(flags: QEventLoop::AllEvents);
77 QCoreApplication::sendPostedEvents(receiver: nullptr, event_type: QEvent::DeferredDelete);
78
79 remaining = deadline.remainingTime();
80 if (remaining > 0)
81 QTestPrivate::qSleep(ms: qMin(a: 10, b: remaining));
82
83 if (predicate())
84 return true;
85
86 remaining = deadline.remainingTime();
87 } while (remaining > 0);
88
89 return predicate(); // Last chance
90}
91
92Q_CORE_EXPORT void qWait(int ms);
93
94} // namespace QTest
95
96QT_END_NAMESPACE
97
98#endif
99

source code of qtbase/src/corelib/kernel/qtestsupport_core.h