cmd/goimports/goimports.go - tools - Git at Google

 // 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")
 }

 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 {
 			err = ioutil.WriteFile(filename, res, 0)
 			if err != nil {
 				return err
 			}
 		}
 		if *doDiff {
 			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 diff(b1, b2 []byte, filename string) (data []byte, err error) {
 	f1, err := ioutil.TempFile("", "gofmt")
 	if err != nil {
 		return
 	}
 	defer os.Remove(f1.Name())
 	defer f1.Close()

 	f2, err := ioutil.TempFile("", "gofmt")
 	if err != nil {
 		return
 	}
 	defer os.Remove(f2.Name())
 	defer f2.Close()

 	f1.Write(b1)
 	f2.Write(b2)

 	cmd := "diff"
 	if runtime.GOOS == "plan9" {
 		cmd = "/bin/ape/diff"
 	}

 	data, err = exec.Command(cmd, "-u", f1.Name(), f2.Name()).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.
 		err = nil

 		data, err = 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()
 }
	// 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")
	}

	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 {
	err = ioutil.WriteFile(filename, res, 0)
	if err != nil {
	return err
	}
	}
	if *doDiff {
	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 diff(b1, b2 []byte, filename string) (data []byte, err error) {
	f1, err := ioutil.TempFile("", "gofmt")
	if err != nil {
	return
	}
	defer os.Remove(f1.Name())
	defer f1.Close()

	f2, err := ioutil.TempFile("", "gofmt")
	if err != nil {
	return
	}
	defer os.Remove(f2.Name())
	defer f2.Close()

	f1.Write(b1)
	f2.Write(b2)

	cmd := "diff"
	if runtime.GOOS == "plan9" {
	cmd = "/bin/ape/diff"
	}

	data, err = exec.Command(cmd, "-u", f1.Name(), f2.Name()).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.
	err = nil

	data, err = 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()
	}