From 499812e8021a18c25647d65825ba1c43073495e1 Mon Sep 17 00:00:00 2001
From: kpango <kpango@vdaas.org>
Date: Fri, 18 Nov 2022 15:50:29 +0900
Subject: [PATCH] [patch] remove time.Local for resolving race condition

Signed-off-by: kpango <kpango@vdaas.org>
---
 example/main.go |  5 +++++
 fastime.go      | 11 +++++++++--
 now.go          | 14 +++++++++++---
 3 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/example/main.go b/example/main.go
index 5e50cb5..d8c8f83 100644
--- a/example/main.go
+++ b/example/main.go
@@ -25,6 +25,11 @@ func main() {
 		fastime.UnixNanoNow()+int64(time.Second),
 		string(fastime.FormattedNow()))
 
+	go func(){
+		time.Sleep(time.Second * 2)
+		fastime.SetLocation(time.FixedZone("Asia/Tokyo", 9*60*60))
+	}()
+
 	for i := 0; i < 30; i++ {
 		time.Sleep(time.Millisecond * 400)
 		fmt.Println(fastime.Now())
diff --git a/fastime.go b/fastime.go
index 5f8fa06..9fc069f 100644
--- a/fastime.go
+++ b/fastime.go
@@ -66,7 +66,7 @@ func newFastime() *fastime {
 		}(),
 		location: func() *atomic.Value {
 			av := new(atomic.Value)
-			av.Store(time.Local)
+			av.Store(new(time.Location))
 			return av
 		}(),
 		correctionDur: time.Millisecond * 100,
@@ -116,7 +116,11 @@ func (f *fastime) IsDaemonRunning() bool {
 }
 
 func (f *fastime) GetLocation() *time.Location {
-	return f.location.Load().(*time.Location)
+	l := f.location.Load()
+	if l == nil{
+		return nil
+	}
+	return l.(*time.Location)
 }
 
 func (f *fastime) GetFormat() string {
@@ -125,6 +129,9 @@ func (f *fastime) GetFormat() string {
 
 // SetLocation replaces time location
 func (f *fastime) SetLocation(location *time.Location) Fastime {
+	if location == nil{
+		return f
+	}
 	f.location.Store(location)
 	f.refresh()
 	return f
diff --git a/now.go b/now.go
index 3643822..53ec5d6 100644
--- a/now.go
+++ b/now.go
@@ -8,12 +8,20 @@ import (
 	"time"
 )
 
-func (f *fastime) now() time.Time {
+func (f *fastime) now() (now time.Time) {
 	var tv syscall.Timeval
 	err := syscall.Gettimeofday(&tv)
 	loc := f.GetLocation()
 	if err != nil {
-		return time.Now().In(loc)
+		now = time.Now()
+		if loc != nil{
+		    return now.In(loc)
+		}
+		return now
 	}
-	return time.Unix(0, syscall.TimevalToNsec(tv)).In(loc)
+	now = time.Unix(0, syscall.TimevalToNsec(tv))
+	if loc != nil{
+	    return now.In(loc)
+	}
+	return now
 }