R: Optimize and remove unnecessary code

common/homedir.go

@@ -1,176 +0,0 @@
-//----------------------------------------
-//
-// Copyright © yanghy. All Rights Reserved.
-//
-// Licensed under Apache License Version 2.0, January 2004
-//
-// https://www.apache.org/licenses/LICENSE-2.0
-//
-//----------------------------------------
-
-package common
-
-import (
-	"bytes"
-	"errors"
-	"os"
-	"os/exec"
-	"path/filepath"
-	"strconv"
-	"strings"
-	"sync"
-)
-
-// DisableCache will disable caching of the home directory. Caching is enabled
-// by default.
-var DisableCache bool
-
-var homedirCache string
-var cacheLock sync.RWMutex
-
-// Dir returns the home directory for the executing user.
-//
-// This uses an OS-specific method for discovering the home directory.
-// An error is returned if a home directory cannot be detected.
-func Dir() (string, error) {
-	if !DisableCache {
-		cacheLock.RLock()
-		cached := homedirCache
-		cacheLock.RUnlock()
-		if cached != "" {
-			return cached, nil
-		}
-	}
-
-	cacheLock.Lock()
-	defer cacheLock.Unlock()
-
-	var result string
-	var err error
-	if IsWindows() {
-		result, err = dirWindows()
-	} else {
-		// Unix-like system, so just assume Unix
-		result, err = dirUnix()
-	}
-
-	if err != nil {
-		return "", err
-	}
-	homedirCache = result
-	return result, nil
-}
-
-// Expand expands the path to include the home directory if the path
-// is prefixed with `~`. If it isn't prefixed with `~`, the path is
-// returned as-is.
-func Expand(path string) (string, error) {
-	if len(path) == 0 {
-		return path, nil
-	}
-
-	if path[0] != '~' {
-		return path, nil
-	}
-
-	if len(path) > 1 && path[1] != '/' && path[1] != '\\' {
-		return "", errors.New("cannot expand user-specific home dir")
-	}
-
-	dir, err := Dir()
-	if err != nil {
-		return "", err
-	}
-
-	return filepath.Join(dir, path[1:]), nil
-}
-
-// Reset clears the cache, forcing the next call to Dir to re-detect
-// the home directory. This generally never has to be called, but can be
-// useful in tests if you're modifying the home directory via the HOME
-// env var or something.
-func Reset() {
-	cacheLock.Lock()
-	defer cacheLock.Unlock()
-	homedirCache = ""
-}
-
-func dirUnix() (string, error) {
-	homeEnv := "HOME"
-	if IsPlan9() {
-		// On plan9, env vars are lowercase.
-		homeEnv = "home"
-	}
-
-	// First prefer the HOME environmental variable
-	if home := os.Getenv(homeEnv); home != "" {
-		return home, nil
-	}
-
-	var stdout bytes.Buffer
-
-	// If that fails, try OS specific commands
-	if IsDarwin() {
-		cmd := exec.Command("sh", "-c", `dscl -q . -read /Users/"$(whoami)" NFSHomeDirectory | sed 's/^[^ ]*: //'`)
-		cmd.Stdout = &stdout
-		if err := cmd.Run(); err == nil {
-			result := strings.TrimSpace(stdout.String())
-			if result != "" {
-				return result, nil
-			}
-		}
-	} else {
-		cmd := exec.Command("getent", "passwd", strconv.Itoa(os.Getuid()))
-		cmd.Stdout = &stdout
-		if err := cmd.Run(); err != nil {
-			// If the error is ErrNotFound, we ignore it. Otherwise, return it.
-			if err != exec.ErrNotFound {
-				return "", err
-			}
-		} else {
-			if passwd := strings.TrimSpace(stdout.String()); passwd != "" {
-				// username:password:uid:gid:gecos:home:shell
-				passwdParts := strings.SplitN(passwd, ":", 7)
-				if len(passwdParts) > 5 {
-					return passwdParts[5], nil
-				}
-			}
-		}
-	}
-
-	// If all else fails, try the shell
-	stdout.Reset()
-	cmd := exec.Command("sh", "-c", "cd && pwd")
-	cmd.Stdout = &stdout
-	if err := cmd.Run(); err != nil {
-		return "", err
-	}
-
-	result := strings.TrimSpace(stdout.String())
-	if result == "" {
-		return "", errors.New("blank output when reading home directory")
-	}
-
-	return result, nil
-}
-
-func dirWindows() (string, error) {
-	// First prefer the HOME environmental variable
-	if home := os.Getenv("HOME"); home != "" {
-		return home, nil
-	}
-
-	// Prefer standard environment variable USERPROFILE
-	if home := os.Getenv("USERPROFILE"); home != "" {
-		return home, nil
-	}
-
-	drive := os.Getenv("HOMEDRIVE")
-	path := os.Getenv("HOMEPATH")
-	home := drive + path
-	if drive == "" || path == "" {
-		return "", errors.New("HOMEDRIVE, HOMEPATH, or USERPROFILE are blank")
-	}
-
-	return home, nil
-}