added Clock class which provides a monotonic clock on most platforms and is now used by Poco::Timer, Poco::Stopwatch, Poco::TimedNotificationQueue and Poco::UtilTimer to avoid issues when the system time is changed

Foundation/src/Clock.cpp

@@ -0,0 +1,234 @@
+//
+// Clock.cpp
+//
+// $Id: //poco/1.4/Foundation/src/Clock.cpp#2 $
+//
+// Library: Foundation
+// Package: DateTime
+// Module:  Clock
+//
+// Copyright (c) 2013, Applied Informatics Software Engineering GmbH.
+// and Contributors.
+//
+// Permission is hereby granted, free of charge, to any person or organization
+// obtaining a copy of the software and accompanying documentation covered by
+// this license (the "Software") to use, reproduce, display, distribute,
+// execute, and transmit the Software, and to prepare derivative works of the
+// Software, and to permit third-parties to whom the Software is furnished to
+// do so, all subject to the following:
+// 
+// The copyright notices in the Software and this entire statement, including
+// the above license grant, this restriction and the following disclaimer,
+// must be included in all copies of the Software, in whole or in part, and
+// all derivative works of the Software, unless such copies or derivative
+// works are solely in the form of machine-executable object code generated by
+// a source language processor.
+// 
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
+// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
+// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
+// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+//
+
+
+#include "Poco/Clock.h"
+#include "Poco/Exception.h"
+#if defined(__MACH__)
+#include <mach/mach.h>
+#include <mach/clock.h>
+#elif defined(POCO_OS_FAMILY_UNIX)
+#include <time.h>
+#elif defined(POCO_VXWORKS)
+#include <timers.h>
+#elif defined(POCO_OS_FAMILY_WINDOWS)
+#include "Poco/UnWindows.h"
+#endif
+#include <algorithm>
+
+
+namespace Poco {
+
+
+Clock::Clock()
+{
+	update();
+}
+
+
+Clock::Clock(ClockVal tv)
+{
+	_clock = tv;
+}
+
+
+Clock::Clock(const Clock& other)
+{
+	_clock = other._clock;
+}
+
+
+Clock::~Clock()
+{
+}
+
+
+Clock& Clock::operator = (const Clock& other)
+{
+	_clock = other._clock;
+	return *this;
+}
+
+
+Clock& Clock::operator = (ClockVal tv)
+{
+	_clock = tv;
+	return *this;
+}
+
+
+void Clock::swap(Clock& timestamp)
+{
+	std::swap(_clock, timestamp._clock);
+}
+
+
+void Clock::update()
+{
+#if defined(POCO_OS_FAMILY_WINDOWS)
+
+	LARGE_INTEGER perfCounter;
+	LARGE_INTEGER perfFreq;
+	if (QueryPerformanceCounter(&perfCounter) && QueryPerformanceFrequency(&perfFreq))
+	{
+		_clock = perfCounter.QuadPart*resolution()/perfFreq.QuadPart;
+	}
+	else throw Poco::SystemException("cannot get system clock");
+
+#elif defined(__MACH__)
+
+	clock_serv_t cs;
+	mach_timespec_t ts;
+
+	host_get_clock_service(mach_host_self(), SYSTEM_CLOCK, &cs);
+	clock_get_time(cs, &ts);
+	mach_port_deallocate(mach_task_self(), cs);
+	
+	_clock = ClockVal(ts.tv_sec)*resolution() + ts.tv_nsec/1000;
+
+#elif defined(POCO_VXWORKS)
+
+	struct timespec ts;
+#if defined(CLOCK_MONOTONIC) // should be in VxWorks 6.x
+	if (clock_gettime(CLOCK_MONOTONIC, &ts))
+		throw SystemException("cannot get system clock");
+#else
+	if (clock_gettime(CLOCK_REALTIME, &ts))
+		throw SystemException("cannot get system clock");
+#endif
+	_clock = ClockVal(ts.tv_sec)*resolution() + ts.tv_nsec/1000;
+
+#elif defined(_POSIX_TIMERS) && defined(_POSIX_MONOTONIC_CLOCK)
+
+	struct timespec ts;
+	if (clock_gettime(CLOCK_MONOTONIC, &ts))
+		throw SystemException("cannot get system clock");
+	_clock = ClockVal(ts.tv_sec)*resolution() + ts.tv_nsec/1000;
+
+#else
+
+	Poco::Timestamp now;
+	_clock = now.epochMicroseconds();
+	
+#endif
+}
+
+
+Clock::ClockVal Clock::accuracy()
+{
+#if defined(POCO_OS_FAMILY_WINDOWS)
+
+	LARGE_INTEGER perfFreq;
+	if (QueryPerformanceFrequency(&perfFreq) && perfFreq.QuadPart > 0)
+	{
+		ClockVal acc = resolution()/perfFreq.QuadPart;
+		return acc > 0 ? acc : 1;
+	}
+	else throw Poco::SystemException("cannot get system clock accuracy");
+
+#elif defined(__MACH__)
+
+	clock_serv_t cs;
+	int nanosecs;
+	mach_msg_type_number_t n = 1;
+
+	host_get_clock_service(mach_host_self(), SYSTEM_CLOCK, &cs);
+	clock_get_attributes(cs, CLOCK_GET_TIME_RES, (clock_attr_t)&nanosecs, &n);
+	mach_port_deallocate(mach_task_self(), cs);
+	
+	ClockVal acc = nanosecs/1000;
+	return acc > 0 ? acc : 1;
+
+#elif defined(POCO_VXWORKS)
+
+	struct timespec ts;
+#if defined(CLOCK_MONOTONIC) // should be in VxWorks 6.x
+	if (clock_getres(CLOCK_MONOTONIC, &ts))
+		throw SystemException("cannot get system clock");
+#else
+	if (clock_getres(CLOCK_REALTIME, &ts))
+		throw SystemException("cannot get system clock");
+#endif
+	ClockVal acc = ClockVal(ts.tv_sec)*resolution() + ts.tv_nsec/1000;
+	return acc > 0 ? acc : 1;
+
+#elif defined(_POSIX_TIMERS) && defined(_POSIX_MONOTONIC_CLOCK)
+
+	struct timespec ts;
+	if (clock_getres(CLOCK_MONOTONIC, &ts))
+		throw SystemException("cannot get system clock");
+	
+	ClockVal acc = ClockVal(ts.tv_sec)*resolution() + ts.tv_nsec/1000;
+	return acc > 0 ? acc : 1;
+
+#else
+
+	return 1000;
+	
+#endif
+}
+
+	
+bool Clock::monotonic()
+{
+#if defined(POCO_OS_FAMILY_WINDOWS)
+
+	return true;
+
+#elif defined(__MACH__)
+
+	return true;
+
+#elif defined(POCO_VXWORKS)
+
+#if defined(CLOCK_MONOTONIC) // should be in VxWorks 6.x
+	return true;
+#else
+	return false;
+#endif
+
+#elif defined(_POSIX_TIMERS) && defined(_POSIX_MONOTONIC_CLOCK)
+
+	return true;
+
+#else
+
+	return false;
+	
+#endif
+}
+
+
+} // namespace Poco