1 // Copyright 2009 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package main 6 7 import ( 8 "bytes" 9 "flag" 10 "fmt" 11 "go/ast" 12 "go/parser" 13 "go/printer" 14 "go/scanner" 15 "go/token" 16 "internal/format" 17 "io" 18 "io/ioutil" 19 "os" 20 "os/exec" 21 "path/filepath" 22 "runtime/pprof" 23 "strings" 24 ) 25 26 var ( 27 // main operation modes 28 list = flag.Bool("l", false, "list files whose formatting differs from gofmt's") 29 write = flag.Bool("w", false, "write result to (source) file instead of stdout") 30 rewriteRule = flag.String("r", "", "rewrite rule (e.g., 'a[b:len(a)] -> a[b:]')") 31 simplifyAST = flag.Bool("s", false, "simplify code") 32 doDiff = flag.Bool("d", false, "display diffs instead of rewriting files") 33 allErrors = flag.Bool("e", false, "report all errors (not just the first 10 on different lines)") 34 35 // debugging 36 cpuprofile = flag.String("cpuprofile", "", "write cpu profile to this file") 37 ) 38 39 const ( 40 tabWidth = 8 41 printerMode = printer.UseSpaces | printer.TabIndent 42 ) 43 44 var ( 45 fileSet = token.NewFileSet() // per process FileSet 46 exitCode = 0 47 rewrite func(*ast.File) *ast.File 48 parserMode parser.Mode 49 ) 50 51 func report(err error) { 52 scanner.PrintError(os.Stderr, err) 53 exitCode = 2 54 } 55 56 func usage() { 57 fmt.Fprintf(os.Stderr, "usage: gofmt [flags] [path ...]\n") 58 flag.PrintDefaults() 59 os.Exit(2) 60 } 61 62 func initParserMode() { 63 parserMode = parser.ParseComments 64 if *allErrors { 65 parserMode |= parser.AllErrors 66 } 67 } 68 69 func isGoFile(f os.FileInfo) bool { 70 // ignore non-Go files 71 name := f.Name() 72 return !f.IsDir() && !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".go") 73 } 74 75 // If in == nil, the source is the contents of the file with the given filename. 76 func processFile(filename string, in io.Reader, out io.Writer, stdin bool) error { 77 if in == nil { 78 f, err := os.Open(filename) 79 if err != nil { 80 return err 81 } 82 defer f.Close() 83 in = f 84 } 85 86 src, err := ioutil.ReadAll(in) 87 if err != nil { 88 return err 89 } 90 91 file, sourceAdj, indentAdj, err := format.Parse(fileSet, filename, src, stdin) 92 if err != nil { 93 return err 94 } 95 96 if rewrite != nil { 97 if sourceAdj == nil { 98 file = rewrite(file) 99 } else { 100 fmt.Fprintf(os.Stderr, "warning: rewrite ignored for incomplete programs\n") 101 } 102 } 103 104 ast.SortImports(fileSet, file) 105 106 if *simplifyAST { 107 simplify(file) 108 } 109 110 res, err := format.Format(fileSet, file, sourceAdj, indentAdj, src, printer.Config{Mode: printerMode, Tabwidth: tabWidth}) 111 if err != nil { 112 return err 113 } 114 115 if !bytes.Equal(src, res) { 116 // formatting has changed 117 if *list { 118 fmt.Fprintln(out, filename) 119 } 120 if *write { 121 err = ioutil.WriteFile(filename, res, 0644) 122 if err != nil { 123 return err 124 } 125 } 126 if *doDiff { 127 data, err := diff(src, res) 128 if err != nil { 129 return fmt.Errorf("computing diff: %s", err) 130 } 131 fmt.Printf("diff %s gofmt/%s\n", filename, filename) 132 out.Write(data) 133 } 134 } 135 136 if !*list && !*write && !*doDiff { 137 _, err = out.Write(res) 138 } 139 140 return err 141 } 142 143 func visitFile(path string, f os.FileInfo, err error) error { 144 if err == nil && isGoFile(f) { 145 err = processFile(path, nil, os.Stdout, false) 146 } 147 if err != nil { 148 report(err) 149 } 150 return nil 151 } 152 153 func walkDir(path string) { 154 filepath.Walk(path, visitFile) 155 } 156 157 func main() { 158 // call gofmtMain in a separate function 159 // so that it can use defer and have them 160 // run before the exit. 161 gofmtMain() 162 os.Exit(exitCode) 163 } 164 165 func gofmtMain() { 166 flag.Usage = usage 167 flag.Parse() 168 169 if *cpuprofile != "" { 170 f, err := os.Create(*cpuprofile) 171 if err != nil { 172 fmt.Fprintf(os.Stderr, "creating cpu profile: %s\n", err) 173 exitCode = 2 174 return 175 } 176 defer f.Close() 177 pprof.StartCPUProfile(f) 178 defer pprof.StopCPUProfile() 179 } 180 181 initParserMode() 182 initRewrite() 183 184 if flag.NArg() == 0 { 185 if *write { 186 fmt.Fprintln(os.Stderr, "error: cannot use -w with standard input") 187 exitCode = 2 188 return 189 } 190 if err := processFile("<standard input>", os.Stdin, os.Stdout, true); err != nil { 191 report(err) 192 } 193 return 194 } 195 196 for i := 0; i < flag.NArg(); i++ { 197 path := flag.Arg(i) 198 switch dir, err := os.Stat(path); { 199 case err != nil: 200 report(err) 201 case dir.IsDir(): 202 walkDir(path) 203 default: 204 if err := processFile(path, nil, os.Stdout, false); err != nil { 205 report(err) 206 } 207 } 208 } 209 } 210 211 func diff(b1, b2 []byte) (data []byte, err error) { 212 f1, err := ioutil.TempFile("", "gofmt") 213 if err != nil { 214 return 215 } 216 defer os.Remove(f1.Name()) 217 defer f1.Close() 218 219 f2, err := ioutil.TempFile("", "gofmt") 220 if err != nil { 221 return 222 } 223 defer os.Remove(f2.Name()) 224 defer f2.Close() 225 226 f1.Write(b1) 227 f2.Write(b2) 228 229 data, err = exec.Command("diff", "-u", f1.Name(), f2.Name()).CombinedOutput() 230 if len(data) > 0 { 231 // diff exits with a non-zero status when the files don't match. 232 // Ignore that failure as long as we get output. 233 err = nil 234 } 235 return 236 237 } 238
