time: Add ability to specialize system and steady clocks
Default implementation is "optimized" to use boost::chrono clocks. When
specialization is used, now() calls are redirected to the virtual
methods of the specified specialization.
This commit also includes an implementation of UnitTestClock that
can be used in unit tests to eliminate dependency on the wall clock.
Change-Id: I7ced774634d90ce32714a71e2a66129cba91b9ae
Refs: #2158
diff --git a/src/util/time.hpp b/src/util/time.hpp
index 92cedce..e0f64c5 100644
--- a/src/util/time.hpp
+++ b/src/util/time.hpp
@@ -24,6 +24,8 @@
#include "../common.hpp"
#include <boost/chrono.hpp>
+#include <boost/asio/time_traits.hpp>
+#include <boost/date_time/posix_time/posix_time_types.hpp>
namespace ndn {
namespace time {
@@ -61,18 +63,29 @@
* <code>
* system_clock::TimePoint time = ...;
* uint64_t timestampInMilliseconds = toUnixTimestamp(time).count();
- * system_clock::TimePoint time2 = fromUnixTimestamp(time::milliseconds(timestampInMilliseconds));
+ * system_clock::TimePoint time2 = fromUnixTimestamp(milliseconds(timestampInMilliseconds));
* </code>
*/
-class system_clock : public boost::chrono::system_clock
+class system_clock
{
public:
+ typedef BOOST_SYSTEM_CLOCK_DURATION duration;
+ typedef duration::rep rep;
+ typedef duration::period period;
+ typedef boost::chrono::time_point<system_clock> time_point;
+ static constexpr bool is_steady = false;
+
typedef time_point TimePoint;
typedef duration Duration;
- // /// \brief Get current TimePoint
- // TimePoint
- // now();
+ static time_point
+ now() noexcept;
+
+ static std::time_t
+ to_time_t(const time_point& t) noexcept;
+
+ static time_point
+ from_time_t(std::time_t t) noexcept;
}; // class system_clock
/**
@@ -82,56 +95,55 @@
* clock cannot decrease as physical time moves forward. This clock is
* not related to wall clock time, and is best suitable for measuring
* intervals.
- *
- * Note that on OS X platform this defaults to system clock and is not
- * truly monotonic. Refer to https://svn.boost.org/trac/boost/ticket/7719)
*/
-class steady_clock : public
-#ifdef __APPLE__
-// steady_clock may go backwards on OS X platforms, so use system_clock
-// instead
- boost::chrono::system_clock
-#else
- boost::chrono::steady_clock
-#endif
+class steady_clock
{
public:
+ typedef nanoseconds duration;
+ typedef duration::rep rep;
+ typedef duration::period period;
+ typedef boost::chrono::time_point<steady_clock> time_point;
+ static constexpr bool is_steady = true;
+
typedef time_point TimePoint;
typedef duration Duration;
- // /// \brief Get current TimePoint
- // TimePoint
- // now();
+ static time_point
+ now() noexcept;
+
+private:
+ /**
+ * \brief Method to be used in deadline timer to select proper waiting
+ *
+ * Mock time implementations should return minimum value to ensure Boost.Asio
+ * is not enabling any waiting on mock timers.
+ *
+ * @sa http://stackoverflow.com/questions/14191855/how-do-you-mock-the-time-for-boost-timers
+ */
+ static boost::posix_time::time_duration
+ to_posix_duration(const duration& duration);
+
+ friend struct boost::asio::time_traits<steady_clock>;
}; // class steady_clock
/**
* \brief Get system_clock::TimePoint representing UNIX time epoch (00:00:00 on Jan 1, 1970)
*/
-inline const system_clock::TimePoint&
-getUnixEpoch()
-{
- static system_clock::TimePoint epoch = system_clock::from_time_t(0);
- return epoch;
-}
+const system_clock::TimePoint&
+getUnixEpoch();
/**
* \brief Convert system_clock::TimePoint to UNIX timestamp
*/
-inline milliseconds
-toUnixTimestamp(const system_clock::TimePoint& point)
-{
- return duration_cast<milliseconds>(point - getUnixEpoch());
-}
+milliseconds
+toUnixTimestamp(const system_clock::TimePoint& point);
/**
* \brief Convert UNIX timestamp to system_clock::TimePoint
*/
-inline system_clock::TimePoint
-fromUnixTimestamp(const milliseconds& duration)
-{
- return getUnixEpoch() + duration;
-}
+system_clock::TimePoint
+fromUnixTimestamp(const milliseconds& duration);
/**
* \brief Convert to the ISO string representation of the time (YYYYMMDDTHHMMSS,fffffffff)
@@ -200,7 +212,30 @@
const std::string& format = "%Y-%m-%d %H:%M:%S",
const std::locale& locale = std::locale("C"));
+
+////////////////////////////////////////////////////////////////////////////////
+
} // namespace time
} // namespace ndn
+namespace boost {
+namespace chrono {
+
+template<class CharT>
+struct clock_string<ndn::time::system_clock, CharT>
+{
+ static std::basic_string<CharT>
+ since();
+};
+
+template<class CharT>
+struct clock_string<ndn::time::steady_clock, CharT>
+{
+ static std::basic_string<CharT>
+ since();
+};
+
+} // namespace chrono
+} // namespace boost
+
#endif // NDN_TIME_HPP