core/elapsedtimer: add ElapsedTimer

src/core/elapsedtimer.hpp

@@ -0,0 +1,45 @@
+#pragma once
+
+#include <qelapsedtimer.h>
+#include <qobject.h>
+#include <qqmlintegration.h>
+#include <qtmetamacros.h>
+#include <qtypes.h>
+
+///! Measures time between events
+/// The ElapsedTimer measures time since its last restart, and is useful
+/// for determining the time between events that don't supply it.
+class ElapsedTimer: public QObject {
+	Q_OBJECT;
+	QML_ELEMENT;
+
+public:
+	explicit ElapsedTimer();
+
+	/// Return the number of seconds since the timer was last
+	/// started or restarted, with nanosecond precision.
+	Q_INVOKABLE qreal elapsed();
+
+	/// Restart the timer, returning the number of seconds since
+	/// the timer was last started or restarted, with nanosecond precision.
+	Q_INVOKABLE qreal restart();
+
+	/// Return the number of milliseconds since the timer was last
+	/// started or restarted.
+	Q_INVOKABLE qint64 elapsedMs();
+
+	/// Restart the timer, returning the number of milliseconds since
+	/// the timer was last started or restarted.
+	Q_INVOKABLE qint64 restartMs();
+
+	/// Return the number of nanoseconds since the timer was last
+	/// started or restarted.
+	Q_INVOKABLE qint64 elapsedNs();
+
+	/// Restart the timer, returning the number of nanoseconds since
+	/// the timer was last started or restarted.
+	Q_INVOKABLE qint64 restartNs();
+
+private:
+	QElapsedTimer timer;
+};