Fix the remainingTime() result after the first activation of a QTimer

On Windows, t->timeout was updated only once, at creation time, so the
timer would always show as "overdue" after the first activation.

The timer is updated to indicate the full remaining time during the slot
activation, which is the behavior of the Unix and Glib dispatchers.

Task-number: QTBUG-46940
Change-Id: I255870833a024a36adf6ffff13ecadb021c4358c
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@theqtcompany.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 58 insertions, 1 deletions

diff --git a/tests/auto/corelib/kernel/qtimer/tst_qtimer.cpp b/tests/auto/corelib/kernel/qtimer/tst_qtimer.cpp
index c7011dbc04..1d1432f600 100644
--- a/tests/auto/corelib/kernel/qtimer/tst_qtimer.cpp
+++ b/tests/auto/corelib/kernel/qtimer/tst_qtimer.cpp
@@ -54,6 +54,8 @@ private slots:
     void singleShotTimeout();
     void timeout();
     void remainingTime();
+    void remainingTimeDuringActivation_data();
+    void remainingTimeDuringActivation();
     void livelock_data();
     void livelock();
     void timerInfiniteRecursion_data();
@@ -79,14 +81,16 @@ class TimerHelper : public QObject
 {
     Q_OBJECT
 public:
-    TimerHelper() : QObject(), count(0)
+    TimerHelper() : QObject(), count(0), remainingTime(-1)
     {
     }
 
     int count;
+    int remainingTime;
 
 public slots:
     void timeout();
+    void fetchRemainingTime();
 };
 
 void TimerHelper::timeout()
@@ -94,6 +98,12 @@ void TimerHelper::timeout()
     ++count;
 }
 
+void TimerHelper::fetchRemainingTime()
+{
+    QTimer *timer = static_cast<QTimer *>(sender());
+    remainingTime = timer->remainingTime();
+}
+
 void tst_QTimer::zeroTimer()
 {
     TimerHelper helper;
@@ -158,6 +168,53 @@ void tst_QTimer::remainingTime()
 
     int remainingTime = timer.remainingTime();
     QVERIFY2(qAbs(remainingTime - 150) < 50, qPrintable(QString::number(remainingTime)));
+
+    // wait for the timer to actually fire now
+    connect(&timer, SIGNAL(timeout()), &QTestEventLoop::instance(), SLOT(exitLoop()));
+    QTestEventLoop::instance().enterLoop(5);
+    QVERIFY(!QTestEventLoop::instance().timeout());
+    QCOMPARE(helper.count, 1);
+
+    // the timer is still active, so it should have a non-zero remaining time
+    remainingTime = timer.remainingTime();
+    QVERIFY2(remainingTime > 150, qPrintable(QString::number(remainingTime)));
+}
+
+void tst_QTimer::remainingTimeDuringActivation_data()
+{
+    QTest::addColumn<bool>("singleShot");
+    QTest::newRow("repeating") << true;
+    QTest::newRow("single-shot") << true;
+}
+
+void tst_QTimer::remainingTimeDuringActivation()
+{
+    QFETCH(bool, singleShot);
+
+    TimerHelper helper;
+    QTimer timer;
+
+    const int timeout = 20;     // 20 ms is short enough and should not round down to 0 in any timer mode
+
+    connect(&timer, SIGNAL(timeout()), &helper, SLOT(fetchRemainingTime()));
+    connect(&timer, SIGNAL(timeout()), &QTestEventLoop::instance(), SLOT(exitLoop()));
+    timer.start(timeout);
+    timer.setSingleShot(singleShot);
+
+    QTestEventLoop::instance().enterLoop(5);
+    QVERIFY(!QTestEventLoop::instance().timeout());
+    if (singleShot)
+        QCOMPARE(helper.remainingTime, -1);     // timer not running
+    else
+        QCOMPARE(helper.remainingTime, timeout);
+
+    if (!singleShot) {
+        // do it again - see QTBUG-46940
+        helper.remainingTime = -1;
+        QTestEventLoop::instance().enterLoop(5);
+        QVERIFY(!QTestEventLoop::instance().timeout());
+        QCOMPARE(helper.remainingTime, timeout);
+    }
 }
 
 void tst_QTimer::livelock_data()