From c81fd071e618740fac9351fdc0e47d654d65a156 Mon Sep 17 00:00:00 2001
From: Gunnar Beutner <gunnar.beutner@netways.de>
Date: Tue, 25 Sep 2012 14:03:41 +0200
Subject: [PATCH] Detect local time changes.

---
 lib/base/application.cpp | 16 ++++++++++++++++
 lib/base/timer.cpp       | 13 +++++++++++++
 lib/base/timer.h         |  1 +
 3 files changed, 30 insertions(+)

diff --git a/lib/base/application.cpp b/lib/base/application.cpp
index fc36f4605..0838ea918 100644
--- a/lib/base/application.cpp
+++ b/lib/base/application.cpp
@@ -99,6 +99,8 @@ void Application::RunEventLoop(void)
 	double nextProfile = 0;
 #endif /* _DEBUG */
 
+	double lastLoop = Utility::GetTime();
+
 	while (!m_ShuttingDown) {
 		Object::ClearHeldObjects();
 
@@ -123,6 +125,20 @@ void Application::RunEventLoop(void)
 			nextProfile = Utility::GetTime() + 15.0;
 		}
 #endif /* _DEBUG */
+
+		double now = Utility::GetTime();
+
+		if (now < lastLoop) {
+			/* We moved backwards in time - cool. */
+			double lostTime = lastLoop - now;
+			stringstream msgbuf;
+			msgbuf << "We moved backwards in time: " << lostTime
+			       << " seconds";
+			Logger::Write(LogInformation, "base", msgbuf.str());
+			Timer::AdjustTimers(-lostTime);
+		}
+
+		lastLoop = now;
 	}
 }
 
diff --git a/lib/base/timer.cpp b/lib/base/timer.cpp
index ce2436908..faa8cf1eb 100644
--- a/lib/base/timer.cpp
+++ b/lib/base/timer.cpp
@@ -155,3 +155,16 @@ void Timer::Reschedule(double next)
 {
 	m_Next = next;
 }
+
+/**
+ * Adjusts all timers by adding the specified amount of time to their
+ * next scheduled timestamp.
+ *
+ * @param adjustment The adjustment.
+ */
+void Timer::AdjustTimers(double adjustment)
+{
+	BOOST_FOREACH(Timer::Ptr timer, m_Timers) {
+		timer->m_Next += adjustment;
+	}
+}
diff --git a/lib/base/timer.h b/lib/base/timer.h
index 2cde7360e..ab32c624c 100644
--- a/lib/base/timer.h
+++ b/lib/base/timer.h
@@ -43,6 +43,7 @@ public:
 	double GetInterval(void) const;
 
 	static double ProcessTimers(void);
+	static void AdjustTimers(double adjustment);
 
 	void Start(void);
 	void Stop(void);