code review 158090043: go.crypto/ssh/terminal: fix crash when terminal narrowe...

go.crypto/ssh/terminal: fix crash when terminal narrower than prompt.

Previously, if the current line was "empty", resizes wouldn't trigger
repaints. However, the line can be empty when the prompt is non-empty
and the code would then panic after a resize because the cursor position
was outside of the terminal.

[bradfitz, 2014-10-19 13:39:58]

LGTM


On Sat, Oct 18, 2014 at 11:13 PM, <agl@golang.org> wrote:

> Reviewers: bradfitz,
>
> Description:
> go.crypto/ssh/terminal: fix crash when terminal narrower than prompt.
>
> Previously, if the current line was "empty", resizes wouldn't trigger
> repaints. However, the line can be empty when the prompt is non-empty
> and the code would then panic after a resize because the cursor position
> was outside of the terminal.
>
> Please review this at https://codereview.appspot.com/158090043/
>
> Affected files (+8, -1 lines):
>   M ssh/terminal/terminal.go
>
>
> Index: ssh/terminal/terminal.go
> ===================================================================
> --- a/ssh/terminal/terminal.go
> +++ b/ssh/terminal/terminal.go
> @@ -732,11 +732,15 @@
>         t.lock.Lock()
>         defer t.lock.Unlock()
>
> +       if width == 0 {
> +               width = 1
> +       }
> +
>         oldWidth := t.termWidth
>         t.termWidth, t.termHeight = width, height
>
>         switch {
> -       case width == oldWidth || len(t.line) == 0:
> +       case width == oldWidth:
>                 // If the width didn't change then nothing else needs to be
>                 // done.
>                 return nil
> @@ -752,6 +756,9 @@
>                 // wrapping and turning into two. This causes the prompt on
>                 // xterms to move upwards, which isn't great, but it
> avoids a
>                 // huge mess with gnome-terminal.
> +               if t.cursorX >= t.termWidth {
> +                       t.cursorX = t.termWidth - 1
> +               }
>                 t.cursorY *= 2
>                 t.clearAndRepaintLinePlusNPrevious(t.maxLine * 2)
>         case width > oldWidth:
>
>
>

[agl1, 2014-10-25 18:16:05]

Hello bradfitz@golang.org (cc: golang-codereviews@googlegroups.com),

I'd like you to review this change to
https://code.google.com/p/go.crypto/

[agl1, 2014-10-25 18:16:27]

*** Submitted as
https://code.google.com/p/go/source/detail?r=43bd7e5d279a&repo=crypto ***

go.crypto/ssh/terminal: fix crash when terminal narrower than prompt.

Previously, if the current line was "empty", resizes wouldn't trigger
repaints. However, the line can be empty when the prompt is non-empty
and the code would then panic after a resize because the cursor position
was outside of the terminal.

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://codereview.appspot.com/158090043