os/user: update stub documentation

R=golang-dev, minux.ma, bradfitz
CC=golang-dev
https://golang.org/cl/6844088

src/pkg/os/user/lookup.go

+// Copyright 2011 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.
+
+package user
+
+// Current returns the current user.
+func Current() (*User, error) {
+	return current()
+}
+
+// Lookup looks up a user by username. If the user cannot be found, the
+// returned error is of type UnknownUserError.
+func Lookup(username string) (*User, error) {
+	return lookup(username)
+}
+
+// LookupId looks up a user by userid. If the user cannot be found, the
+// returned error is of type UnknownUserIdError.
+func LookupId(uid string) (*User, error) {
+	return lookupId(uid)
+}

src/pkg/os/user/lookup_stubs.go

@@ -15,14 +15,14 @@ func init() {
 	implemented = false
 }
 
-func Current() (*User, error) {
+func current() (*User, error) {
 	return nil, fmt.Errorf("user: Current not implemented on %s/%s", runtime.GOOS, runtime.GOARCH)
 }
 
-func Lookup(username string) (*User, error) {
+func lookup(username string) (*User, error) {
 	return nil, fmt.Errorf("user: Lookup not implemented on %s/%s", runtime.GOOS, runtime.GOARCH)
 }
 
-func LookupId(string) (*User, error) {
+func lookupId(uid string) (*User, error) {
 	return nil, fmt.Errorf("user: LookupId not implemented on %s/%s", runtime.GOOS, runtime.GOARCH)
 }

src/pkg/os/user/lookup_unix.go

@@ -29,28 +29,23 @@ static int mygetpwuid_r(int uid, struct passwd *pwd,
 */
 import "C"
 
-// Current returns the current user.
-func Current() (*User, error) {
-	return lookup(syscall.Getuid(), "", false)
+func current() (*User, error) {
+	return lookupUnix(syscall.Getuid(), "", false)
 }
 
-// Lookup looks up a user by username. If the user cannot be found,
-// the returned error is of type UnknownUserError.
-func Lookup(username string) (*User, error) {
-	return lookup(-1, username, true)
+func lookup(username string) (*User, error) {
+	return lookupUnix(-1, username, true)
 }
 
-// LookupId looks up a user by userid. If the user cannot be found,
-// the returned error is of type UnknownUserIdError.
-func LookupId(uid string) (*User, error) {
+func lookupId(uid string) (*User, error) {
 	i, e := strconv.Atoi(uid)
 	if e != nil {
 		return nil, e
 	}
-	return lookup(i, "", false)
+	return lookupUnix(i, "", false)
 }
 
-func lookup(uid int, username string, lookupByName bool) (*User, error) {
+func lookupUnix(uid int, username string, lookupByName bool) (*User, error) {
 	var pwd C.struct_passwd
 	var result *C.struct_passwd
 

src/pkg/os/user/lookup_windows.go

@@ -68,8 +68,7 @@ func newUser(usid *syscall.SID, gid, dir string) (*User, error) {
 	return u, nil
 }
 
-// Current returns the current user.
-func Current() (*User, error) {
+func current() (*User, error) {
 	t, e := syscall.OpenCurrentProcessToken()
 	if e != nil {
 		return nil, e
@@ -103,8 +102,7 @@ func newUserFromSid(usid *syscall.SID) (*User, error) {
 	return newUser(usid, gid, dir)
 }
 
-// Lookup looks up a user by username.
-func Lookup(username string) (*User, error) {
+func lookup(username string) (*User, error) {
 	sid, _, t, e := syscall.LookupSID("", username)
 	if e != nil {
 		return nil, e
@@ -115,8 +113,7 @@ func Lookup(username string) (*User, error) {
 	return newUserFromSid(sid)
 }
 
-// LookupId looks up a user by userid.
-func LookupId(uid string) (*User, error) {
+func lookupId(uid string) (*User, error) {
 	sid, e := syscall.StringToSid(uid)
 	if e != nil {
 		return nil, e