1 files changed, 271 insertions, 0 deletions
diff --git a/src/cmd/fix/main.go b/src/cmd/fix/main.go
new file mode 100644
index 000000000..b151408d7
--- /dev/null
+++ b/src/cmd/fix/main.go
@@ -0,0 +1,271 @@
+// Copyright 2011 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/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+var (
+	fset     = token.NewFileSet()
+	exitCode = 0
+)
+
+var allowedRewrites = flag.String("r", "",
+	"restrict the rewrites to this comma-separated list")
+
+var forceRewrites = flag.String("force", "",
+	"force these fixes to run even if the code looks updated")
+
+var allowed, force map[string]bool
+
+var doDiff = flag.Bool("diff", false, "display diffs instead of rewriting files")
+
+// enable for debugging fix failures
+const debug = false // display incorrectly reformatted source and exit
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "usage: go tool fix [-diff] [-r fixname,...] [-force fixname,...] [path ...]\n")
+	flag.PrintDefaults()
+	fmt.Fprintf(os.Stderr, "\nAvailable rewrites are:\n")
+	sort.Sort(byName(fixes))
+	for _, f := range fixes {
+		fmt.Fprintf(os.Stderr, "\n%s\n", f.name)
+		desc := strings.TrimSpace(f.desc)
+		desc = strings.Replace(desc, "\n", "\n\t", -1)
+		fmt.Fprintf(os.Stderr, "\t%s\n", desc)
+	}
+	os.Exit(2)
+}
+
+func main() {
+	flag.Usage = usage
+	flag.Parse()
+
+	sort.Sort(byDate(fixes))
+
+	if *allowedRewrites != "" {
+		allowed = make(map[string]bool)
+		for _, f := range strings.Split(*allowedRewrites, ",") {
+			allowed[f] = true
+		}
+	}
+
+	if *forceRewrites != "" {
+		force = make(map[string]bool)
+		for _, f := range strings.Split(*forceRewrites, ",") {
+			force[f] = true
+		}
+	}
+
+	if flag.NArg() == 0 {
+		if err := processFile("standard input", true); err != nil {
+			report(err)
+		}
+		os.Exit(exitCode)
+	}
+
+	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, false); err != nil {
+				report(err)
+			}
+		}
+	}
+
+	os.Exit(exitCode)
+}
+
+const (
+	tabWidth    = 8
+	parserMode  = parser.ParseComments
+	printerMode = printer.TabIndent | printer.UseSpaces
+)
+
+var printConfig = &printer.Config{
+	Mode:     printerMode,
+	Tabwidth: tabWidth,
+}
+
+func gofmtFile(f *ast.File) ([]byte, error) {
+	var buf bytes.Buffer
+
+	ast.SortImports(fset, f)
+	err := printConfig.Fprint(&buf, fset, f)
+	if err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+func processFile(filename string, useStdin bool) error {
+	var f *os.File
+	var err error
+	var fixlog bytes.Buffer
+
+	if useStdin {
+		f = os.Stdin
+	} else {
+		f, err = os.Open(filename)
+		if err != nil {
+			return err
+		}
+		defer f.Close()
+	}
+
+	src, err := ioutil.ReadAll(f)
+	if err != nil {
+		return err
+	}
+
+	file, err := parser.ParseFile(fset, filename, src, parserMode)
+	if err != nil {
+		return err
+	}
+
+	// Apply all fixes to file.
+	newFile := file
+	fixed := false
+	for _, fix := range fixes {
+		if allowed != nil && !allowed[fix.name] {
+			continue
+		}
+		if fix.f(newFile) {
+			fixed = true
+			fmt.Fprintf(&fixlog, " %s", fix.name)
+
+			// AST changed.
+			// Print and parse, to update any missing scoping
+			// or position information for subsequent fixers.
+			newSrc, err := gofmtFile(newFile)
+			if err != nil {
+				return err
+			}
+			newFile, err = parser.ParseFile(fset, filename, newSrc, parserMode)
+			if err != nil {
+				if debug {
+					fmt.Printf("%s", newSrc)
+					report(err)
+					os.Exit(exitCode)
+				}
+				return err
+			}
+		}
+	}
+	if !fixed {
+		return nil
+	}
+	fmt.Fprintf(os.Stderr, "%s: fixed %s\n", filename, fixlog.String()[1:])
+
+	// Print AST.  We did that after each fix, so this appears
+	// redundant, but it is necessary to generate gofmt-compatible
+	// source code in a few cases.  The official gofmt style is the
+	// output of the printer run on a standard AST generated by the parser,
+	// but the source we generated inside the loop above is the
+	// output of the printer run on a mangled AST generated by a fixer.
+	newSrc, err := gofmtFile(newFile)
+	if err != nil {
+		return err
+	}
+
+	if *doDiff {
+		data, err := diff(src, newSrc)
+		if err != nil {
+			return fmt.Errorf("computing diff: %s", err)
+		}
+		fmt.Printf("diff %s fixed/%s\n", filename, filename)
+		os.Stdout.Write(data)
+		return nil
+	}
+
+	if useStdin {
+		os.Stdout.Write(newSrc)
+		return nil
+	}
+
+	return ioutil.WriteFile(f.Name(), newSrc, 0)
+}
+
+var gofmtBuf bytes.Buffer
+
+func gofmt(n interface{}) string {
+	gofmtBuf.Reset()
+	err := printConfig.Fprint(&gofmtBuf, fset, n)
+	if err != nil {
+		return "<" + err.Error() + ">"
+	}
+	return gofmtBuf.String()
+}
+
+func report(err error) {
+	scanner.PrintError(os.Stderr, err)
+	exitCode = 2
+}
+
+func walkDir(path string) {
+	filepath.Walk(path, visitFile)
+}
+
+func visitFile(path string, f os.FileInfo, err error) error {
+	if err == nil && isGoFile(f) {
+		err = processFile(path, false)
+	}
+	if err != nil {
+		report(err)
+	}
+	return nil
+}
+
+func isGoFile(f os.FileInfo) bool {
+	// ignore non-Go files
+	name := f.Name()
+	return !f.IsDir() && !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".go")
+}
+
+func diff(b1, b2 []byte) (data []byte, err error) {
+	f1, err := ioutil.TempFile("", "go-fix")
+	if err != nil {
+		return nil, err
+	}
+	defer os.Remove(f1.Name())
+	defer f1.Close()
+
+	f2, err := ioutil.TempFile("", "go-fix")
+	if err != nil {
+		return nil, err
+	}
+	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
+}