src/cmd/gofmt/gofmt.go - go - Git at Google

 // 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"
 	"os/exec"
 	"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., '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")
 )

 const (
 	tabWidth    = 8
 	printerMode = printer.UseSpaces | printer.TabIndent
 )

 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()
 	os.Exit(2)
 }

 func initParserMode() {
 	parserMode = parser.ParseComments
 	if *allErrors {
 		parserMode |= parser.AllErrors
 	}
 }

 func isGoFile(f os.FileInfo) 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 {
 	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, 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 {
 			err = ioutil.WriteFile(filename, res, 0644)
 			if err != nil {
 				return err
 			}
 		}
 		if *doDiff {
 			data, err := diff(src, res)
 			if err != nil {
 				return fmt.Errorf("computing diff: %s", err)
 			}
 			fmt.Printf("diff %s gofmt/%s\n", filename, 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, false)
 	}
 	if err != nil {
 		report(err)
 	}
 	return nil
 }

 func walkDir(path string) {
 	filepath.Walk(path, visitFile)
 }

 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()

 	if flag.NArg() == 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 i := 0; i < flag.NArg(); i++ {
 		path := flag.Arg(i)
 		switch dir, err := os.Stat(path); {
 		case err != nil:
 			report(err)
 		case dir.IsDir():
 			walkDir(path)
 		default:
 			if err := processFile(path, nil, os.Stdout, false); err != nil {
 				report(err)
 			}
 		}
 	}
 }

 func diff(b1, b2 []byte) (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)

 	data, err = exec.Command("diff", "-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
 	}
 	return

 }

 // ----------------------------------------------------------------------------
 // Support functions
 //
 // The functions parse, format, and isSpace below are identical to the
 // respective functions in src/go/format/format.go - keep them in sync!
 //
 // TODO(gri) Factor out this functionality, eventually.

 // parse parses src, which was read from the named file,
 // as a Go source file, declaration, or statement list.
 func parse(fset *token.FileSet, filename string, src []byte, fragmentOk bool) (
 	file *ast.File,
 	sourceAdj func(src []byte, indent int) []byte,
 	indentAdj int,
 	err error,
 ) {
 	// Try as whole source file.
 	file, err = parser.ParseFile(fset, filename, src, parserMode)
 	// If there's no error, return.  If the error is that the source file didn't begin with a
 	// package line and source fragments are ok, fall through to
 	// try as a source fragment.  Stop and return on any other error.
 	if err == nil || !fragmentOk || !strings.Contains(err.Error(), "expected 'package'") {
 		return
 	}

 	// If this is a declaration list, make it a source file
 	// by inserting a package clause.
 	// Insert using a ;, not a newline, so that the line numbers
 	// in psrc match the ones in src.
 	psrc := append([]byte("package p;"), src...)
 	file, err = parser.ParseFile(fset, filename, psrc, parserMode)
 	if err == nil {
 		sourceAdj = func(src []byte, indent int) []byte {
 			// Remove the package clause.
 			// Gofmt has turned the ; into a \n.
 			src = src[indent+len("package p\n"):]
 			return bytes.TrimSpace(src)
 		}
 		return
 	}
 	// If the error is that the source file didn't begin with a
 	// declaration, fall through to try as a statement list.
 	// Stop and return on any other error.
 	if !strings.Contains(err.Error(), "expected declaration") {
 		return
 	}

 	// If this is a statement list, make it a source file
 	// by inserting a package clause and turning the list
 	// into a function body.  This handles expressions too.
 	// Insert using a ;, not a newline, so that the line numbers
 	// in fsrc match the ones in src.
 	fsrc := append(append([]byte("package p; func _() {"), src...), '\n', '}')
 	file, err = parser.ParseFile(fset, filename, fsrc, parserMode)
 	if err == nil {
 		sourceAdj = func(src []byte, indent int) []byte {
 			// Cap adjusted indent to zero.
 			if indent < 0 {
 				indent = 0
 			}
 			// Remove the wrapping.
 			// Gofmt has turned the ; into a \n\n.
 			// There will be two non-blank lines with indent, hence 2*indent.
 			src = src[2*indent+len("package p\n\nfunc _() {"):]
 			src = src[:len(src)-(indent+len("\n}\n"))]
 			return bytes.TrimSpace(src)
 		}
 		// Gofmt has also indented the function body one level.
 		// Adjust that with indentAdj.
 		indentAdj = -1
 	}

 	// Succeeded, or out of options.
 	return
 }

 // format formats the given package file originally obtained from src
 // and adjusts the result based on the original source via sourceAdj
 // and indentAdj.
 func format(
 	fset *token.FileSet,
 	file *ast.File,
 	sourceAdj func(src []byte, indent int) []byte,
 	indentAdj int,
 	src []byte,
 	cfg printer.Config,
 ) ([]byte, error) {
 	if sourceAdj == nil {
 		// Complete source file.
 		var buf bytes.Buffer
 		err := cfg.Fprint(&buf, fset, file)
 		if err != nil {
 			return nil, err
 		}
 		return buf.Bytes(), nil
 	}

 	// Partial source file.
 	// Determine and prepend leading space.
 	i, j := 0, 0
 	for j < len(src) && isSpace(src[j]) {
 		if src[j] == '\n' {
 			i = j + 1 // byte offset of last line in leading space
 		}
 		j++
 	}
 	var res []byte
 	res = append(res, src[:i]...)

 	// Determine and prepend indentation of first code line.
 	// Spaces are ignored unless there are no tabs,
 	// in which case spaces count as one tab.
 	indent := 0
 	hasSpace := false
 	for _, b := range src[i:j] {
 		switch b {
 		case ' ':
 			hasSpace = true
 		case '\t':
 			indent++
 		}
 	}
 	if indent == 0 && hasSpace {
 		indent = 1
 	}
 	for i := 0; i < indent; i++ {
 		res = append(res, '\t')
 	}

 	// Format the source.
 	// Write it without any leading and trailing space.
 	cfg.Indent = indent + indentAdj
 	var buf bytes.Buffer
 	err := cfg.Fprint(&buf, fset, file)
 	if err != nil {
 		return nil, err
 	}
 	res = append(res, sourceAdj(buf.Bytes(), cfg.Indent)...)

 	// Determine and append trailing space.
 	i = len(src)
 	for i > 0 && isSpace(src[i-1]) {
 		i--
 	}
 	return append(res, src[i:]...), nil
 }

 func isSpace(b byte) bool {
 	return b == ' ' || b == '\t' || b == '\n' || b == '\r'
 }
	// 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"
	"os/exec"
	"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., '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")
	)

	const (
	tabWidth = 8
	printerMode = printer.UseSpaces \| printer.TabIndent
	)

	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()
	os.Exit(2)
	}

	func initParserMode() {
	parserMode = parser.ParseComments
	if *allErrors {
	parserMode \|= parser.AllErrors
	}
	}

	func isGoFile(f os.FileInfo) 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 {
	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, 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 {
	err = ioutil.WriteFile(filename, res, 0644)
	if err != nil {
	return err
	}
	}
	if *doDiff {
	data, err := diff(src, res)
	if err != nil {
	return fmt.Errorf("computing diff: %s", err)
	}
	fmt.Printf("diff %s gofmt/%s\n", filename, 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, false)
	}
	if err != nil {
	report(err)
	}
	return nil
	}

	func walkDir(path string) {
	filepath.Walk(path, visitFile)
	}

	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()

	if flag.NArg() == 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 i := 0; i < flag.NArg(); i++ {
	path := flag.Arg(i)
	switch dir, err := os.Stat(path); {
	case err != nil:
	report(err)
	case dir.IsDir():
	walkDir(path)
	default:
	if err := processFile(path, nil, os.Stdout, false); err != nil {
	report(err)
	}
	}
	}
	}

	func diff(b1, b2 []byte) (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)

	data, err = exec.Command("diff", "-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
	}
	return

	}

	// ----------------------------------------------------------------------------
	// Support functions
	//
	// The functions parse, format, and isSpace below are identical to the
	// respective functions in src/go/format/format.go - keep them in sync!
	//
	// TODO(gri) Factor out this functionality, eventually.

	// parse parses src, which was read from the named file,
	// as a Go source file, declaration, or statement list.
	func parse(fset *token.FileSet, filename string, src []byte, fragmentOk bool) (
	file *ast.File,
	sourceAdj func(src []byte, indent int) []byte,
	indentAdj int,
	err error,
	) {
	// Try as whole source file.
	file, err = parser.ParseFile(fset, filename, src, parserMode)
	// If there's no error, return. If the error is that the source file didn't begin with a
	// package line and source fragments are ok, fall through to
	// try as a source fragment. Stop and return on any other error.
	if err == nil \|\| !fragmentOk \|\| !strings.Contains(err.Error(), "expected 'package'") {
	return
	}

	// If this is a declaration list, make it a source file
	// by inserting a package clause.
	// Insert using a ;, not a newline, so that the line numbers
	// in psrc match the ones in src.
	psrc := append([]byte("package p;"), src...)
	file, err = parser.ParseFile(fset, filename, psrc, parserMode)
	if err == nil {
	sourceAdj = func(src []byte, indent int) []byte {
	// Remove the package clause.
	// Gofmt has turned the ; into a \n.
	src = src[indent+len("package p\n"):]
	return bytes.TrimSpace(src)
	}
	return
	}
	// If the error is that the source file didn't begin with a
	// declaration, fall through to try as a statement list.
	// Stop and return on any other error.
	if !strings.Contains(err.Error(), "expected declaration") {
	return
	}

	// If this is a statement list, make it a source file
	// by inserting a package clause and turning the list
	// into a function body. This handles expressions too.
	// Insert using a ;, not a newline, so that the line numbers
	// in fsrc match the ones in src.
	fsrc := append(append([]byte("package p; func _() {"), src...), '\n', '}')
	file, err = parser.ParseFile(fset, filename, fsrc, parserMode)
	if err == nil {
	sourceAdj = func(src []byte, indent int) []byte {
	// Cap adjusted indent to zero.
	if indent < 0 {
	indent = 0
	}
	// Remove the wrapping.
	// Gofmt has turned the ; into a \n\n.
	// There will be two non-blank lines with indent, hence 2*indent.
	src = src[2*indent+len("package p\n\nfunc _() {"):]
	src = src[:len(src)-(indent+len("\n}\n"))]
	return bytes.TrimSpace(src)
	}
	// Gofmt has also indented the function body one level.
	// Adjust that with indentAdj.
	indentAdj = -1
	}

	// Succeeded, or out of options.
	return
	}

	// format formats the given package file originally obtained from src
	// and adjusts the result based on the original source via sourceAdj
	// and indentAdj.
	func format(
	fset *token.FileSet,
	file *ast.File,
	sourceAdj func(src []byte, indent int) []byte,
	indentAdj int,
	src []byte,
	cfg printer.Config,
	) ([]byte, error) {
	if sourceAdj == nil {
	// Complete source file.
	var buf bytes.Buffer
	err := cfg.Fprint(&buf, fset, file)
	if err != nil {
	return nil, err
	}
	return buf.Bytes(), nil
	}

	// Partial source file.
	// Determine and prepend leading space.
	i, j := 0, 0
	for j < len(src) && isSpace(src[j]) {
	if src[j] == '\n' {
	i = j + 1 // byte offset of last line in leading space
	}
	j++
	}
	var res []byte
	res = append(res, src[:i]...)

	// Determine and prepend indentation of first code line.
	// Spaces are ignored unless there are no tabs,
	// in which case spaces count as one tab.
	indent := 0
	hasSpace := false
	for _, b := range src[i:j] {
	switch b {
	case ' ':
	hasSpace = true
	case '\t':
	indent++
	}
	}
	if indent == 0 && hasSpace {
	indent = 1
	}
	for i := 0; i < indent; i++ {
	res = append(res, '\t')
	}

	// Format the source.
	// Write it without any leading and trailing space.
	cfg.Indent = indent + indentAdj
	var buf bytes.Buffer
	err := cfg.Fprint(&buf, fset, file)
	if err != nil {
	return nil, err
	}
	res = append(res, sourceAdj(buf.Bytes(), cfg.Indent)...)

	// Determine and append trailing space.
	i = len(src)
	for i > 0 && isSpace(src[i-1]) {
	i--
	}
	return append(res, src[i:]...), nil
	}

	func isSpace(b byte) bool {
	return b == ' ' \|\| b == '\t' \|\| b == '\n' \|\| b == '\r'
	}