github.com/axw/llgo@v0.0.0-20160805011314-95b5fe4dca20/third_party/gofrontend/libgo/go/time/zoneinfo_unix.go (about)

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // +build darwin,386 darwin,amd64 dragonfly freebsd linux nacl netbsd openbsd solaris
     6  
     7  // Parse "zoneinfo" time zone file.
     8  // This is a fairly standard file format used on OS X, Linux, BSD, Sun, and others.
     9  // See tzfile(5), http://en.wikipedia.org/wiki/Zoneinfo,
    10  // and ftp://munnari.oz.au/pub/oldtz/
    11  
    12  package time
    13  
    14  import (
    15  	"errors"
    16  	"runtime"
    17  	"syscall"
    18  )
    19  
    20  func initTestingZone() {
    21  	syscall.Setenv("TZ", "America/Los_Angeles")
    22  	initLocal()
    23  }
    24  
    25  // Many systems use /usr/share/zoneinfo, Solaris 2 has
    26  // /usr/share/lib/zoneinfo, IRIX 6 has /usr/lib/locale/TZ.
    27  var zoneDirs = []string{
    28  	"/usr/share/zoneinfo/",
    29  	"/usr/share/lib/zoneinfo/",
    30  	"/usr/lib/locale/TZ/",
    31  	runtime.GOROOT() + "/lib/time/zoneinfo.zip",
    32  }
    33  
    34  var origZoneDirs = zoneDirs
    35  
    36  func forceZipFileForTesting(zipOnly bool) {
    37  	zoneDirs = make([]string, len(origZoneDirs))
    38  	copy(zoneDirs, origZoneDirs)
    39  	if zipOnly {
    40  		for i := 0; i < len(zoneDirs)-1; i++ {
    41  			zoneDirs[i] = "/XXXNOEXIST"
    42  		}
    43  	}
    44  }
    45  
    46  func initLocal() {
    47  	// consult $TZ to find the time zone to use.
    48  	// no $TZ means use the system default /etc/localtime.
    49  	// $TZ="" means use UTC.
    50  	// $TZ="foo" means use /usr/share/zoneinfo/foo.
    51  
    52  	tz, ok := syscall.Getenv("TZ")
    53  	switch {
    54  	case !ok:
    55  		z, err := loadZoneFile("", "/etc/localtime")
    56  		if err == nil {
    57  			localLoc = *z
    58  			localLoc.name = "Local"
    59  			return
    60  		}
    61  	case tz != "" && tz != "UTC":
    62  		if z, err := loadLocation(tz); err == nil {
    63  			localLoc = *z
    64  			return
    65  		}
    66  	}
    67  
    68  	// Fall back to UTC.
    69  	localLoc.name = "UTC"
    70  }
    71  
    72  func loadLocation(name string) (*Location, error) {
    73  	var firstErr error
    74  	for _, zoneDir := range zoneDirs {
    75  		if z, err := loadZoneFile(zoneDir, name); err == nil {
    76  			z.name = name
    77  			return z, nil
    78  		} else if firstErr == nil && !isNotExist(err) {
    79  			firstErr = err
    80  		}
    81  	}
    82  	if firstErr != nil {
    83  		return nil, firstErr
    84  	}
    85  	return nil, errors.New("unknown time zone " + name)
    86  }