src

goimports.go (10075B)

---

 // 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"
 	"log"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"runtime"
 	"runtime/pprof"
 	"strings"
 	"testing"
 
 	"golang.org/x/telemetry/counter"
 	"golang.org/x/tools/internal/gocommand"
 	"golang.org/x/tools/internal/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,
 		Env: &imports.ProcessEnv{
 			GocmdRunner: &gocommand.Runner{},
 		},
 	}
 	exitCode = 0
 )
 
 func init() {
 	flag.BoolVar(&options.AllErrors, "e", false, "report all errors (not just the first 10 on different lines)")
 	flag.StringVar(&options.LocalPrefix, "local", "", "put imports beginning with this string after 3rd-party packages; comma-separated list")
 	flag.BoolVar(&options.FormatOnly, "format-only", false, "if true, don't fix imports and only format. In this mode, goimports is effectively gofmt, with the addition that imports are grouped into sections.")
 }
 
 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 := io.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")
 			}
 			// On Windows, we need to re-set the permissions from the file. See golang/go#38225.
 			var perms os.FileMode
 			if fi, err := os.Stat(filename); err == nil {
 				perms = fi.Mode() & os.ModePerm
 			}
 			err = os.WriteFile(filename, res, perms)
 			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() {
 	// Measure how many people still use goimports.
 	// (See https://go.dev/issue/78671 for one.)
 	counter.Open()
 	counter.Inc("tools/cmd:goimports")
 	runtime.GOMAXPROCS(runtime.NumCPU())
 
 	// call gofmtMain in a separate function
 	// so that it can use defer and have them
 	// run before the exit.
 	gofmtMain()
 	if !testing.Testing() {
 		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)
 		options.Env.Logf = log.Printf
 	}
 	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 := os.CreateTemp(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] = fmt.Appendf(nil, "--- %s%s", f+".orig", t0)
 	bs[1] = fmt.Appendf(nil, "+++ %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()
 }