code review 4295062: gofmt: add profiling flag

gofmt: add profiling flag

[rsc, 2011-03-23 17:57:00]

Hello gri (cc: golang-dev@googlegroups.com),

I'd like you to review this change to
https://go.googlecode.com/hg

[gri, 2011-03-23 18:00:06]

LGTM
cool.
- Robert

On Wed, Mar 23, 2011 at 10:57 AM,  <rsc@golang.org> wrote:
> Reviewers: gri,
>
> Message:
> Hello gri (cc: golang-dev@googlegroups.com),
>
> I'd like you to review this change to
> https://go.googlecode.com/hg
>
>
> Description:
> gofmt: add profiling flag
>
> Please review this at http://codereview.appspot.com/4295062/
>
> Affected files:
>  M src/cmd/gofmt/gofmt.go
>
>
> Index: src/cmd/gofmt/gofmt.go
> ===================================================================
> --- a/src/cmd/gofmt/gofmt.go
> +++ b/src/cmd/gofmt/gofmt.go
> @@ -16,6 +16,7 @@
>        "io/ioutil"
>        "os"
>        "path/filepath"
> +       "runtime/pprof"
>        "strings"
>  )
>
> @@ -32,6 +33,9 @@
>        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")
>  )
>
>
> @@ -172,11 +176,33 @@
>
>
>  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)
> -               os.Exit(2)
> +               exitCode = 2
> +               return
> +       }
> +
> +       if *cpuprofile != "" {
> +               f, err := os.Open(*cpuprofile,
> os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
> +               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()
> @@ -202,6 +228,4 @@
>                        walkDir(path)
>                }
>        }
> -
> -       os.Exit(exitCode)
>  }
>
>
>

[rsc, 2011-03-23 18:28:40]

*** Submitted as 57f18b5a2df4 ***

gofmt: add profiling flag

R=gri
CC=golang-dev
http://codereview.appspot.com/4295062