golang zoneinfo_unix 代码
文件路径：/src/time/zoneinfo_unix.go
/ Copyright 2009 The Go Authors. All rights reserved.
/ Use of this source code is governed by a BSD-style
/ license that can be found in the LICENSE file.
/go:build unix && !ios && !android
/ Parse "zoneinfo" time zone file.
/ This is a fairly standard file format used on OS X, Linux, BSD, Sun, and others.
/ See tzfile(5), https://en.wikipedia.org/wiki/Zoneinfo,
/ and ftp://munnari.oz.au/pub/oldtz/
package time
import (
"syscall"
)
/ Many systems use /usr/share/zoneinfo, Solaris 2 has
/ /usr/share/lib/zoneinfo, IRIX 6 has /usr/lib/locale/TZ.
var platformZoneSources = []string{
"/usr/share/zoneinfo/",
"/usr/share/lib/zoneinfo/",
"/usr/lib/locale/TZ/",
}
func initLocal() {
/ consult $TZ to find the time zone to use.
/ no $TZ means use the system default /etc/localtime.
/ $TZ="" means use UTC.
/ $TZ="foo" or $TZ=":foo" if foo is an absolute path, then the file pointed
/ by foo will be used to initialize timezone; otherwise, file
/ /usr/share/zoneinfo/foo will be used.
tz, ok := syscall.Getenv("TZ")
switch {
case !ok:
z, err := loadLocation("localtime", []string{"/etc"})
if err == nil {
localLoc = *z
localLoc.name = "Local"
return
}
case tz != "":
if tz[0] == ':' {
tz = tz[1:]
}
if tz != "" && tz[0] == '/' {
if z, err := loadLocation(tz, []string{""}); err == nil {
localLoc = *z
if tz == "/etc/localtime" {
localLoc.name = "Local"
} else {
localLoc.name = tz
}
return
}
} else if tz != "" && tz != "UTC" {
if z, err := loadLocation(tz, platformZoneSources); err == nil {
localLoc = *z
return
}
}
}
/ Fall back to UTC.
localLoc.name = "UTC"
}