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// 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/ioutil"
"os"
"path/filepath"
"runtime/pprof"
"strings"
)
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., 'α[β:len(α)] -> α[β:]')")
simplifyAST = flag.Bool("s", false, "simplify code")
// layout control
comments = flag.Bool("comments", true, "print comments")
tabWidth = flag.Int("tabwidth", 8, "tab width")
tabIndent = flag.Bool("tabindent", true, "indent with tabs independent of -spaces")
useSpaces = flag.Bool("spaces", true, "align with spaces instead of tabs")
// debugging
cpuprofile = flag.String("cpuprofile", "", "write cpu profile to this file")
)
var (
fset = token.NewFileSet()
exitCode = 0
rewrite func(*ast.File) *ast.File
parserMode uint
printerMode uint
)
func report(err os.Error) {
scanner.PrintError(os.Stderr, err)
exitCode = 2
}
func usage() {
fmt.Fprintf(os.Stderr, "usage: gofmt [flags] [path ...]\n")
flag.PrintDefaults()
os.Exit(2)
}
func initParserMode() {
parserMode = uint(0)
if *comments {
parserMode |= parser.ParseComments
}
}
func initPrinterMode() {
printerMode = uint(0)
if *tabIndent {
printerMode |= printer.TabIndent
}
if *useSpaces {
printerMode |= printer.UseSpaces
}
}
func isGoFile(f *os.FileInfo) bool {
// ignore non-Go files
return f.IsRegular() && !strings.HasPrefix(f.Name, ".") && strings.HasSuffix(f.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) os.Error {
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
}
file, err := parser.ParseFile(fset, filename, src, parserMode)
if err != nil {
return err
}
if rewrite != nil {
file = rewrite(file)
}
if *simplifyAST {
simplify(file)
}
var buf bytes.Buffer
_, err = (&printer.Config{printerMode, *tabWidth}).Fprint(&buf, fset, file)
if err != nil {
return err
}
res := buf.Bytes()
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 !*list && !*write {
_, err = out.Write(res)
}
return err
}
type fileVisitor chan os.Error
func (v fileVisitor) VisitDir(path string, f *os.FileInfo) bool {
return true
}
func (v fileVisitor) VisitFile(path string, f *os.FileInfo) {
if isGoFile(f) {
v <- nil // synchronize error handler
if err := processFile(path, nil, os.Stdout); err != nil {
v <- err
}
}
}
func walkDir(path string) {
v := make(fileVisitor)
go func() {
filepath.Walk(path, v, v)
close(v)
}()
for err := range v {
if err != nil {
report(err)
}
}
}
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 *tabWidth < 0 {
fmt.Fprintf(os.Stderr, "negative tabwidth %d\n", *tabWidth)
exitCode = 2
return
}
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()
initPrinterMode()
initRewrite()
if flag.NArg() == 0 {
if err := processFile("<standard input>", os.Stdin, os.Stdout); err != nil {
report(err)
}
return
}
for i := 0; i < flag.NArg(); i++ {
path := flag.Arg(i)
switch dir, err := os.Stat(path); {
case err != nil:
report(err)
case dir.IsRegular():
if err := processFile(path, nil, os.Stdout); err != nil {
report(err)
}
case dir.IsDirectory():
walkDir(path)
}
}
}
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