Display ui time with customize time location (#7792)

* display ui time with customize time location

* fix lint

* rename UILocation to DefaultUILocation

* move time related functions to modules/timeutil

* fix tests

* fix tests

* fix build

* fix swagger

modules/timeutil/timestamp.go

@@ -0,0 +1,81 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package timeutil
+
+import (
+	"time"
+
+	"code.gitea.io/gitea/modules/setting"
+)
+
+// TimeStamp defines a timestamp
+type TimeStamp int64
+
+// TimeStampNow returns now int64
+func TimeStampNow() TimeStamp {
+	return TimeStamp(time.Now().Unix())
+}
+
+// Add adds seconds and return sum
+func (ts TimeStamp) Add(seconds int64) TimeStamp {
+	return ts + TimeStamp(seconds)
+}
+
+// AddDuration adds time.Duration and return sum
+func (ts TimeStamp) AddDuration(interval time.Duration) TimeStamp {
+	return ts + TimeStamp(interval/time.Second)
+}
+
+// Year returns the time's year
+func (ts TimeStamp) Year() int {
+	return ts.AsTime().Year()
+}
+
+// AsTime convert timestamp as time.Time in Local locale
+func (ts TimeStamp) AsTime() (tm time.Time) {
+	return ts.AsTimeInLocation(setting.DefaultUILocation)
+}
+
+// AsTimeInLocation convert timestamp as time.Time in Local locale
+func (ts TimeStamp) AsTimeInLocation(loc *time.Location) (tm time.Time) {
+	tm = time.Unix(int64(ts), 0).In(loc)
+	return
+}
+
+// AsTimePtr convert timestamp as *time.Time in Local locale
+func (ts TimeStamp) AsTimePtr() *time.Time {
+	return ts.AsTimePtrInLocation(setting.DefaultUILocation)
+}
+
+// AsTimePtrInLocation convert timestamp as *time.Time in customize location
+func (ts TimeStamp) AsTimePtrInLocation(loc *time.Location) *time.Time {
+	tm := time.Unix(int64(ts), 0).In(loc)
+	return &tm
+}
+
+// Format formats timestamp as given format
+func (ts TimeStamp) Format(f string) string {
+	return ts.FormatInLocation(f, setting.DefaultUILocation)
+}
+
+// FormatInLocation formats timestamp as given format with spiecific location
+func (ts TimeStamp) FormatInLocation(f string, loc *time.Location) string {
+	return ts.AsTimeInLocation(loc).Format(f)
+}
+
+// FormatLong formats as RFC1123Z
+func (ts TimeStamp) FormatLong() string {
+	return ts.Format(time.RFC1123Z)
+}
+
+// FormatShort formats as short
+func (ts TimeStamp) FormatShort() string {
+	return ts.Format("Jan 02, 2006")
+}
+
+// IsZero is zero time
+func (ts TimeStamp) IsZero() bool {
+	return ts.AsTimeInLocation(time.Local).IsZero()
+}