Long live QDeadlineTimer

It's like QElapsedTimer, but marks a time in the future instead.

[ChangeLog][QtCore] Added QDeadlineTimer, a counterpart to
QElapsedTimer, used to mark a time point in the future (a deadline) and
determine whether such a deadline has passed.

Change-Id: Ifea6e497f11a461db432ffff144921f7fbc1d1d3
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 22 insertions, 0 deletions

diff --git a/src/corelib/kernel/qelapsedtimer_win.cpp b/src/corelib/kernel/qelapsedtimer_win.cpp
index 520126d262..0c380b2f6a 100644
--- a/src/corelib/kernel/qelapsedtimer_win.cpp
+++ b/src/corelib/kernel/qelapsedtimer_win.cpp
@@ -38,6 +38,8 @@
 ****************************************************************************/
 
 #include "qelapsedtimer.h"
+#include "qdeadlinetimer.h"
+#include "qdeadlinetimer_p.h"
 #include <qt_windows.h>
 
 QT_BEGIN_NAMESPACE
@@ -76,6 +78,17 @@ static inline qint64 ticksToNanoseconds(qint64 ticks)
     }
 }
 
+static inline qint64 nanosecondsToTicks(qint64 nsec)
+{
+    if (counterFrequency > 0) {
+        // QueryPerformanceCounter uses an arbitrary frequency
+        return double(nsec) * counterFrequency / 1000000000.;
+    } else {
+        // GetTickCount(64) uses milliseconds
+        return nsec / 1000000;
+    }
+}
+
 static quint64 getTickCount()
 {
     resolveCounterFrequency();
@@ -161,4 +174,13 @@ bool operator<(const QElapsedTimer &v1, const QElapsedTimer &v2) Q_DECL_NOTHROW
     return (v1.t1 - v2.t1) < 0;
 }
 
+QDeadlineTimer QDeadlineTimer::current(Qt::TimerType timerType) Q_DECL_NOTHROW
+{
+    Q_STATIC_ASSERT(!QDeadlineTimerNanosecondsInT2);
+    QDeadlineTimer result;
+    result.t1 = ticksToNanoseconds(getTickCount());
+    result.type = timerType;
+    return result;
+}
+
 QT_END_NAMESPACE