From 9c1b760016d0ad55ebe5f39f6e3fc272f39b3b68 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Fri, 24 May 2019 02:24:18 +0900
Subject: [PATCH] clock: Bug fix: The timer should continue even when the clock
 is adjusted

If the clock is reversed:
* lastSystemTime should be reset with the current time
* FPS/TPS calculation state should be reset
---
 internal/clock/clock.go | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/internal/clock/clock.go b/internal/clock/clock.go
index 4a0367a62..8ec9b8fbf 100644
--- a/internal/clock/clock.go
+++ b/internal/clock/clock.go
@@ -63,6 +63,7 @@ func calcCountFromTPS(tps int64, now int64) int {
 	diff := now - lastSystemTime
 	if diff < 0 {
 		// It is theoretically possible to change the OS clock, so now can be older than lastSystemTime.
+		lastSystemTime = now
 		return 0
 	}
 
@@ -101,6 +102,13 @@ func updateFPSAndTPS(now int64, count int) {
 	}
 	fpsCount++
 	tpsCount += count
+	if now < lastUpdated {
+		// It is theoretically possible to change the OS clock, so now can be older than lastSystemTime.
+		lastUpdated = now
+		fpsCount = 0
+		tpsCount = 0
+		return
+	}
 	if time.Second > time.Duration(now-lastUpdated) {
 		return
 	}