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// Copyright 2013 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 main
import (
"bufio"
"bytes"
"errors"
"flag"
"fmt"
"go/scanner"
"io"
"io/ioutil"
"log"
"os"
"os/exec"
"path/filepath"
"runtime"
"runtime/pprof"
"strings"
"golang.org/x/tools/imports"
)
var (
// main operation modes
list = flag.Bool("l", false, "list files whose formatting differs from goimport's")
write = flag.Bool("w", false, "write result to (source) file instead of stdout")
doDiff = flag.Bool("d", false, "display diffs instead of rewriting files")
srcdir = flag.String("srcdir", "", "choose imports as if source code is from `dir`. When operating on a single file, dir may instead be the complete file name.")
verbose bool // verbose logging
cpuProfile = flag.String("cpuprofile", "", "CPU profile output")
memProfile = flag.String("memprofile", "", "memory profile output")
memProfileRate = flag.Int("memrate", 0, "if > 0, sets runtime.MemProfileRate")
options = &imports.Options{
TabWidth: 8,
TabIndent: true,
Comments: true,
Fragment: true,
}
exitCode = 0
)
func init() {
flag.BoolVar(&options.AllErrors, "e", false, "report all errors (not just the first 10 on different lines)")
flag.StringVar(&imports.LocalPrefix, "local", "", "put imports beginning with this string after 3rd-party packages; comma-separated list")
}
func report(err error) {
scanner.PrintError(os.Stderr, err)
exitCode = 2
}
func usage() {
fmt.Fprintf(os.Stderr, "usage: goimports [flags] [path ...]\n")
flag.PrintDefaults()
os.Exit(2)
}
func isGoFile(f os.FileInfo) bool {
// ignore non-Go files
name := f.Name()
return !f.IsDir() && !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".go")
}
// argumentType is which mode goimports was invoked as.
type argumentType int
const (
// fromStdin means the user is piping their source into goimports.
fromStdin argumentType = iota
// singleArg is the common case from editors, when goimports is run on
// a single file.
singleArg
// multipleArg is when the user ran "goimports file1.go file2.go"
// or ran goimports on a directory tree.
multipleArg
)
func processFile(filename string, in io.Reader, out io.Writer, argType argumentType) error {
opt := options
if argType == fromStdin {
nopt := *options
nopt.Fragment = true
opt = &nopt
}
if in == nil {
f, err := os.Open(filename)
if err != nil {
return err
}
defer f.Close()
in = f
}
src, err := ioutil.ReadAll(in)
if err != nil {
return err
}
target := filename
if *srcdir != "" {
// Determine whether the provided -srcdirc is a directory or file
// and then use it to override the target.
//
// See https://github.com/dominikh/go-mode.el/issues/146
if isFile(*srcdir) {
if argType == multipleArg {
return errors.New("-srcdir value can't be a file when passing multiple arguments or when walking directories")
}
target = *srcdir
} else if argType == singleArg && strings.HasSuffix(*srcdir, ".go") && !isDir(*srcdir) {
// For a file which doesn't exist on disk yet, but might shortly.
// e.g. user in editor opens $DIR/newfile.go and newfile.go doesn't yet exist on disk.
// The goimports on-save hook writes the buffer to a temp file
// first and runs goimports before the actual save to newfile.go.
// The editor's buffer is named "newfile.go" so that is passed to goimports as:
// goimports -srcdir=/gopath/src/pkg/newfile.go /tmp/gofmtXXXXXXXX.go
// and then the editor reloads the result from the tmp file and writes
// it to newfile.go.
target = *srcdir
} else {
// Pretend that file is from *srcdir in order to decide
// visible imports correctly.
target = filepath.Join(*srcdir, filepath.Base(filename))
}
}
res, err := imports.Process(target, src, opt)
if err != nil {
return err
}
if !bytes.Equal(src, res) {
// formatting has changed
if *list {
fmt.Fprintln(out, filename)
}
if *write {
if argType == fromStdin {
// filename is "<standard input>"
return errors.New("can't use -w on stdin")
}
err = ioutil.WriteFile(filename, res, 0)
if err != nil {
return err
}
}
if *doDiff {
if argType == fromStdin {
filename = "stdin.go" // because <standard input>.orig looks silly
}
data, err := diff(src, res, filename)
if err != nil {
return fmt.Errorf("computing diff: %s", err)
}
fmt.Printf("diff -u %s %s\n", filepath.ToSlash(filename+".orig"), filepath.ToSlash(filename))
out.Write(data)
}
}
if !*list && !*write && !*doDiff {
_, err = out.Write(res)
}
return err
}
func visitFile(path string, f os.FileInfo, err error) error {
if err == nil && isGoFile(f) {
err = processFile(path, nil, os.Stdout, multipleArg)
}
if err != nil {
report(err)
}
return nil
}
func walkDir(path string) {
filepath.Walk(path, visitFile)
}
func main() {
runtime.GOMAXPROCS(runtime.NumCPU())
// call gofmtMain in a separate function
// so that it can use defer and have them
// run before the exit.
gofmtMain()
os.Exit(exitCode)
}
// parseFlags parses command line flags and returns the paths to process.
// It's a var so that custom implementations can replace it in other files.
var parseFlags = func() []string {
flag.BoolVar(&verbose, "v", false, "verbose logging")
flag.Parse()
return flag.Args()
}
func bufferedFileWriter(dest string) (w io.Writer, close func()) {
f, err := os.Create(dest)
if err != nil {
log.Fatal(err)
}
bw := bufio.NewWriter(f)
return bw, func() {
if err := bw.Flush(); err != nil {
log.Fatalf("error flushing %v: %v", dest, err)
}
if err := f.Close(); err != nil {
log.Fatal(err)
}
}
}
func gofmtMain() {
flag.Usage = usage
paths := parseFlags()
if *cpuProfile != "" {
bw, flush := bufferedFileWriter(*cpuProfile)
pprof.StartCPUProfile(bw)
defer flush()
defer pprof.StopCPUProfile()
}
// doTrace is a conditionally compiled wrapper around runtime/trace. It is
// used to allow goimports to compile under gccgo, which does not support
// runtime/trace. See https://golang.org/issue/15544.
defer doTrace()()
if *memProfileRate > 0 {
runtime.MemProfileRate = *memProfileRate
bw, flush := bufferedFileWriter(*memProfile)
defer func() {
runtime.GC() // materialize all statistics
if err := pprof.WriteHeapProfile(bw); err != nil {
log.Fatal(err)
}
flush()
}()
}
if verbose {
log.SetFlags(log.LstdFlags | log.Lmicroseconds)
imports.Debug = true
}
if options.TabWidth < 0 {
fmt.Fprintf(os.Stderr, "negative tabwidth %d\n", options.TabWidth)
exitCode = 2
return
}
if len(paths) == 0 {
if err := processFile("<standard input>", os.Stdin, os.Stdout, fromStdin); err != nil {
report(err)
}
return
}
argType := singleArg
if len(paths) > 1 {
argType = multipleArg
}
for _, path := range paths {
switch dir, err := os.Stat(path); {
case err != nil:
report(err)
case dir.IsDir():
walkDir(path)
default:
if err := processFile(path, nil, os.Stdout, argType); err != nil {
report(err)
}
}
}
}
func writeTempFile(dir, prefix string, data []byte) (string, error) {
file, err := ioutil.TempFile(dir, prefix)
if err != nil {
return "", err
}
_, err = file.Write(data)
if err1 := file.Close(); err == nil {
err = err1
}
if err != nil {
os.Remove(file.Name())
return "", err
}
return file.Name(), nil
}
func diff(b1, b2 []byte, filename string) (data []byte, err error) {
f1, err := writeTempFile("", "gofmt", b1)
if err != nil {
return
}
defer os.Remove(f1)
f2, err := writeTempFile("", "gofmt", b2)
if err != nil {
return
}
defer os.Remove(f2)
cmd := "diff"
if runtime.GOOS == "plan9" {
cmd = "/bin/ape/diff"
}
data, err = exec.Command(cmd, "-u", f1, f2).CombinedOutput()
if len(data) > 0 {
// diff exits with a non-zero status when the files don't match.
// Ignore that failure as long as we get output.
return replaceTempFilename(data, filename)
}
return
}
// replaceTempFilename replaces temporary filenames in diff with actual one.
//
// --- /tmp/gofmt316145376 2017-02-03 19:13:00.280468375 -0500
// +++ /tmp/gofmt617882815 2017-02-03 19:13:00.280468375 -0500
// ...
// ->
// --- path/to/file.go.orig 2017-02-03 19:13:00.280468375 -0500
// +++ path/to/file.go 2017-02-03 19:13:00.280468375 -0500
// ...
func replaceTempFilename(diff []byte, filename string) ([]byte, error) {
bs := bytes.SplitN(diff, []byte{'\n'}, 3)
if len(bs) < 3 {
return nil, fmt.Errorf("got unexpected diff for %s", filename)
}
// Preserve timestamps.
var t0, t1 []byte
if i := bytes.LastIndexByte(bs[0], '\t'); i != -1 {
t0 = bs[0][i:]
}
if i := bytes.LastIndexByte(bs[1], '\t'); i != -1 {
t1 = bs[1][i:]
}
// Always print filepath with slash separator.
f := filepath.ToSlash(filename)
bs[0] = []byte(fmt.Sprintf("--- %s%s", f+".orig", t0))
bs[1] = []byte(fmt.Sprintf("+++ %s%s", f, t1))
return bytes.Join(bs, []byte{'\n'}), nil
}
// isFile reports whether name is a file.
func isFile(name string) bool {
fi, err := os.Stat(name)
return err == nil && fi.Mode().IsRegular()
}
// isDir reports whether name is a directory.
func isDir(name string) bool {
fi, err := os.Stat(name)
return err == nil && fi.IsDir()
}