launchpad.net/~rogpeppe/juju-core/500-errgo-fix@v0.0.0-20140213181702-000000002356/utils/file.go (about) 1 // Copyright 2013 Canonical Ltd. 2 // Licensed under the AGPLv3, see LICENCE file for details. 3 4 package utils 5 6 import ( 7 "fmt" 8 "io" 9 "os" 10 "os/user" 11 "path" 12 "path/filepath" 13 "regexp" 14 "runtime" 15 16 "launchpad.net/juju-core/juju/osenv" 17 ) 18 19 // UserHomeDir returns the home directory for the specified user, or the 20 // home directory for the current user if the specified user is empty. 21 func UserHomeDir(userName string) (homeDir string, err error) { 22 var u *user.User 23 if userName == "" { 24 // TODO (wallyworld) - fix tests on Windows 25 // Ordinarily, we'd always use user.Current() to get the current user 26 // and then get the HomeDir from that. But our tests rely on poking 27 // a value into $HOME in order to override the normal home dir for the 28 // current user. So on *nix, we're forced to use osenv.Home() to make 29 // the tests pass. All of our tests currently construct paths with the 30 // default user in mind eg "~/foo". 31 if runtime.GOOS == "windows" { 32 u, err = user.Current() 33 } else { 34 return osenv.Home(), nil 35 } 36 } else { 37 u, err = user.Lookup(userName) 38 if err != nil { 39 return "", mask(err) 40 } 41 } 42 return u.HomeDir, nil 43 } 44 45 var userHomePathRegexp = regexp.MustCompile("(~(?P<user>[^/]*))(?P<path>.*)") 46 47 // NormalizePath expands a path containing ~ to its absolute form, 48 // and removes any .. or . path elements. 49 func NormalizePath(dir string) (string, error) { 50 if userHomePathRegexp.MatchString(dir) { 51 user := userHomePathRegexp.ReplaceAllString(dir, "$user") 52 userHomeDir, err := UserHomeDir(user) 53 if err != nil { 54 return "", mask(err) 55 } 56 dir = userHomePathRegexp.ReplaceAllString(dir, fmt.Sprintf("%s$path", userHomeDir)) 57 } 58 return filepath.Clean(dir), nil 59 } 60 61 // JoinServerPath joins any number of path elements into a single path, adding 62 // a path separator (based on the current juju server OS) if necessary. The 63 // result is Cleaned; in particular, all empty strings are ignored. 64 func JoinServerPath(elem ...string) string { 65 return path.Join(elem...) 66 } 67 68 // UniqueDirectory returns "path/name" if that directory doesn't exist. If it 69 // does, the method starts appending .1, .2, etc until a unique name is found. 70 func UniqueDirectory(path, name string) (string, error) { 71 dir := filepath.Join(path, name) 72 _, err := os.Stat(dir) 73 if os.IsNotExist(err) { 74 return dir, nil 75 } 76 for i := 1; ; i++ { 77 dir := filepath.Join(path, fmt.Sprintf("%s.%d", name, i)) 78 _, err := os.Stat(dir) 79 if os.IsNotExist(err) { 80 return dir, nil 81 } else if err != nil { 82 return "", mask(err) 83 } 84 } 85 } 86 87 // CopyFile writes the contents of the given source file to dest. 88 func CopyFile(dest, source string) error { 89 df, err := os.Create(dest) 90 if err != nil { 91 return mask(err) 92 } 93 f, err := os.Open(source) 94 if err != nil { 95 return mask(err) 96 } 97 defer f.Close() 98 _, err = io.Copy(df, f) 99 return err 100 }