QQmlIncubationController::incubateWhile: port to atomic<bool>

"volatile bool" does not guarantee synchronization, and as such,
the documentation (and the intended use case, having another
thread stopping incubation) are wrong. Add a different overload
that takes a std::atomic<bool> as a replacement.

Change-Id: I05e2d608385d075ef67989839d6c0a634da7a64b
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

1 files changed, 28 insertions, 3 deletions

diff --git a/src/qml/qml/qqmlincubator.cpp b/src/qml/qml/qqmlincubator.cpp
index f0ef5360b0..d9c965d3ea 100644
--- a/src/qml/qml/qqmlincubator.cpp
+++ b/src/qml/qml/qqmlincubator.cpp
@@ -410,14 +410,39 @@ void QQmlIncubationController::incubateFor(int msecs)
     } while (d && d->incubatorCount != 0 && !i.shouldInterrupt());
 }
 
+#if QT_DEPRECATED_SINCE(5, 15)
 /*!
-Incubate objects while the bool pointed to by \a flag is true, or until there are no
-more objects to incubate, or up to \a msecs if \a msecs is not zero.
+\obsolete
+
+\warning Do not use this function.
+Use the overload taking a \c{std::atomic<bool>} instead.
+*/
+void QQmlIncubationController::incubateWhile(volatile bool *flag, int msecs)
+{
+    if (!d || !d->incubatorCount)
+        return;
+
+    QQmlInstantiationInterrupt i(flag, msecs * 1000000);
+    i.reset();
+    do {
+        static_cast<QQmlIncubatorPrivate*>(d->incubatorList.first())->incubate(i);
+    } while (d && d->incubatorCount != 0 && !i.shouldInterrupt());
+}
+#endif
+
+/*!
+\since 5.15
+
+Incubate objects while the atomic bool pointed to by \a flag is true,
+or until there are no more objects to incubate, or up to \a msecs if \a
+msecs is not zero.
 
 Generally this method is used in conjunction with a thread or a UNIX signal that sets
 the bool pointed to by \a flag to false when it wants incubation to be interrupted.
+
+\note \a flag is read using acquire memory ordering.
 */
-void QQmlIncubationController::incubateWhile(volatile bool *flag, int msecs)
+void QQmlIncubationController::incubateWhile(std::atomic<bool> *flag, int msecs)
 {
     if (!d || !d->incubatorCount)
         return;