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Mini Shell
Mini Shell
// Copyright 2009 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 (
"bytes"
"flag"
"fmt"
"go/ast"
"go/parser"
"go/printer"
"go/scanner"
"go/token"
"io"
"io/fs"
"os"
"path/filepath"
"runtime"
"runtime/pprof"
"strings"
"cmd/internal/diff"
)
var (
// main operation modes
list = flag.Bool("l", false, "list files whose formatting differs from gofmt's")
write = flag.Bool("w", false, "write result to (source) file instead of stdout")
rewriteRule = flag.String("r", "", "rewrite rule (e.g., 'a[b:len(a)] -> a[b:]')")
simplifyAST = flag.Bool("s", false, "simplify code")
doDiff = flag.Bool("d", false, "display diffs instead of rewriting files")
allErrors = flag.Bool("e", false, "report all errors (not just the first 10 on different lines)")
// debugging
cpuprofile = flag.String("cpuprofile", "", "write cpu profile to this file")
)
// Keep these in sync with go/format/format.go.
const (
tabWidth = 8
printerMode = printer.UseSpaces | printer.TabIndent | printerNormalizeNumbers
// printerNormalizeNumbers means to canonicalize number literal prefixes
// and exponents while printing. See https://golang.org/doc/go1.13#gofmt.
//
// This value is defined in go/printer specifically for go/format and cmd/gofmt.
printerNormalizeNumbers = 1 << 30
)
var (
fileSet = token.NewFileSet() // per process FileSet
exitCode = 0
rewrite func(*ast.File) *ast.File
parserMode parser.Mode
)
func report(err error) {
scanner.PrintError(os.Stderr, err)
exitCode = 2
}
func usage() {
fmt.Fprintf(os.Stderr, "usage: gofmt [flags] [path ...]\n")
flag.PrintDefaults()
}
func initParserMode() {
parserMode = parser.ParseComments
if *allErrors {
parserMode |= parser.AllErrors
}
}
func isGoFile(f fs.DirEntry) bool {
// ignore non-Go files
name := f.Name()
return !f.IsDir() && !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".go")
}
// If in == nil, the source is the contents of the file with the given filename.
func processFile(filename string, in io.Reader, out io.Writer, stdin bool) error {
var perm fs.FileMode = 0644
if in == nil {
f, err := os.Open(filename)
if err != nil {
return err
}
defer f.Close()
fi, err := f.Stat()
if err != nil {
return err
}
in = f
perm = fi.Mode().Perm()
}
src, err := io.ReadAll(in)
if err != nil {
return err
}
file, sourceAdj, indentAdj, err := parse(fileSet, filename, src, stdin)
if err != nil {
return err
}
if rewrite != nil {
if sourceAdj == nil {
file = rewrite(file)
} else {
fmt.Fprintf(os.Stderr, "warning: rewrite ignored for incomplete programs\n")
}
}
ast.SortImports(fileSet, file)
if *simplifyAST {
simplify(file)
}
res, err := format(fileSet, file, sourceAdj, indentAdj, src, printer.Config{Mode: printerMode, Tabwidth: tabWidth})
if err != nil {
return err
}
if !bytes.Equal(src, res) {
// formatting has changed
if *list {
fmt.Fprintln(out, filename)
}
if *write {
// make a temporary backup before overwriting original
bakname, err := backupFile(filename+".", src, perm)
if err != nil {
return err
}
err = os.WriteFile(filename, res, perm)
if err != nil {
os.Rename(bakname, filename)
return err
}
err = os.Remove(bakname)
if err != nil {
return err
}
}
if *doDiff {
data, err := diffWithReplaceTempFile(src, res, filename)
if err != nil {
return fmt.Errorf("computing diff: %s", err)
}
fmt.Fprintf(out, "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 fs.DirEntry, err error) error {
if err != nil || !isGoFile(f) {
return err
}
if err := processFile(path, nil, os.Stdout, false); err != nil {
report(err)
}
return nil
}
func main() {
// call gofmtMain in a separate function
// so that it can use defer and have them
// run before the exit.
gofmtMain()
os.Exit(exitCode)
}
func gofmtMain() {
flag.Usage = usage
flag.Parse()
if *cpuprofile != "" {
f, err := os.Create(*cpuprofile)
if err != nil {
fmt.Fprintf(os.Stderr, "creating cpu profile: %s\n", err)
exitCode = 2
return
}
defer f.Close()
pprof.StartCPUProfile(f)
defer pprof.StopCPUProfile()
}
initParserMode()
initRewrite()
args := flag.Args()
if len(args) == 0 {
if *write {
fmt.Fprintln(os.Stderr, "error: cannot use -w with standard input")
exitCode = 2
return
}
if err := processFile("<standard input>", os.Stdin, os.Stdout, true); err != nil {
report(err)
}
return
}
for _, arg := range args {
switch info, err := os.Stat(arg); {
case err != nil:
report(err)
case !info.IsDir():
// Non-directory arguments are always formatted.
if err := processFile(arg, nil, os.Stdout, false); err != nil {
report(err)
}
default:
// Directories are walked, ignoring non-Go files.
if err := filepath.WalkDir(arg, visitFile); err != nil {
report(err)
}
}
}
}
func diffWithReplaceTempFile(b1, b2 []byte, filename string) ([]byte, error) {
data, err := diff.Diff("gofmt", b1, b2)
if len(data) > 0 {
return replaceTempFilename(data, filename)
}
return data, err
}
// 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
}
const chmodSupported = runtime.GOOS != "windows"
// backupFile writes data to a new file named filename<number> with permissions perm,
// with <number randomly chosen such that the file name is unique. backupFile returns
// the chosen file name.
func backupFile(filename string, data []byte, perm fs.FileMode) (string, error) {
// create backup file
f, err := os.CreateTemp(filepath.Dir(filename), filepath.Base(filename))
if err != nil {
return "", err
}
bakname := f.Name()
if chmodSupported {
err = f.Chmod(perm)
if err != nil {
f.Close()
os.Remove(bakname)
return bakname, err
}
}
// write data to backup file
_, err = f.Write(data)
if err1 := f.Close(); err == nil {
err = err1
}
return bakname, err
}
Zerion Mini Shell 1.0