Re: [9front] vt plumbing: empty selection

["Iruatã Souza" <iru.muzgo@gmail.com>]

Ori,

It seems that in surrounding, if x0 == x1 you allocate a one byte
buffer but return nil, effectively leaking that buffer.

On Thu, Apr 9, 2020 at 6:15 AM <ori@eigenstate.org> wrote:
>
> Plumbing text in vt requires selecting the text that you
> want to plumb precisely. This patch makes plumbing behave
> the same way that it does in rio, though cwd isn't updated
> whenever we change directories. That'll take further thought
> to get right.
>
> There's an escape code (OSC 7) for programs to advertise
> their current working directory to the terminal emulator,
> and I'm willing to implement it --  but nothing on 9front
> generates it, and it's not clear that we want to start.
> The programs that do generate it are likely to be on the
> other end of an ssh connection, which means that their cwd
> is unlikely to make sense to plumb. Is there anything that
> is useful to do here?
>
> diff -r 3bcb5998f222 sys/src/cmd/vt/main.c
> --- a/sys/src/cmd/vt/main.c     Wed Apr 08 23:48:09 2020 +0200
> +++ b/sys/src/cmd/vt/main.c     Wed Apr 08 21:07:46 2020 -0700
> @@ -170,7 +170,7 @@
>  void   escapedump(int,uchar *,int);
>  void   paste(void);
>  void   snarfsel(void);
> -void   plumbsel(void);
> +void   plumbsel(Point);
>
>  static Channel *pidchan;
>
> @@ -982,13 +982,47 @@
>         free(s);
>  }
>
> +/*
> + * Grabs the non-whitespace text around a character
> + * cell, matching the behavior in rio for plumbing.
> + * Does not modify the selection.
> + */
> +char*
> +surrounding(Point p)
> +{
> +       int c, x0, x1;
> +       char *s, *e;
> +
> +       for(x0 = p.x; x0 > 0; x0--){
> +               c = *onscreenr(x0 - 1, p.y);
> +               if(c == 0 || c == ' ' || c == '\t' || c == '\n')
> +                       break;
> +       }
> +       for(x1 = p.x; x1 <= xmax; x1++){
> +               c = *onscreenr(x1 + 1, p.y);
> +               if(c == 0 || c == ' ' || c == '\t' || c == '\n')
> +                       break;
> +       }
> +       s = malloc((x1 - x0 + 1)*UTFmax);
> +       if(s == nil || x0 == x1)
> +               return nil;
> +       e = selrange(s, x0, p.y, x1, p.y);
> +       *e = 0;
> +       for(e = s; *e; e++)
> +               print("%c(%d)\n", *e, *e);
> +       return s;
> +}
> +
>  void
> -plumbsel(void)
> +plumbsel(Point p)
>  {
>         char *s, wdir[1024];
>         int plumb;
>
> -       if((s = selection()) == nil)
> +       s = selection();
> +       if(s == nil || *s == 0)
> +               s = surrounding(p);
> +       if(s == nil)
>                 return;
>         if(getwd(wdir, sizeof wdir) == nil){
>                 free(s);
> @@ -1116,6 +1150,9 @@
>  void
>  readmenu(void)
>  {
> +       Point p;
> +
> +       p = pos(mc->xy);
>         if(button3()) {
>                 menu3.item[1] = ttystate[cs->raw].crnl ? "cr" : "crnl";
>                 menu3.item[2] = ttystate[cs->raw].nlcr ? "nl" : "nlcr";
> @@ -1173,7 +1210,7 @@
>                 return;
>
>         case Mplumb:
> -               plumbsel();
> +               plumbsel(p);
>                 return;
>
>         case Mpage:             /* pause and clear at end of screen */
>