Re: [PATCH] column: fix outputing empty column at the end of line

[Yousong Zhou <yszhou4tech@gmail.com>]

Hi Sami,

On Sun, 28 Jul 2019 at 02:49, Sami Kerola <kerolasa@iki.fi> wrote:
>
> On Thu, 27 Jun 2019 at 10:24, Yousong Zhou <yszhou4tech@gmail.com> wrote:
> >
> > The following commands manifests the problem.  In old versions before
> > commit 4762ae9d60 ("column: use libsmartcols for --table"), both of them
> > should output with 2 "|"
> >
> >         echo '||'  | column -o '|' -s '|' -t
> >         echo '|| ' | column -o '|' -s '|' -t
> >
> > Fixes: 4762ae9d60 ("column: use libsmartcols for --table")
> > Signed-off-by: Yousong Zhou <zhouyousong@yunionyun.com>
> > ---
> >  tests/expected/column/table-empty-column-at-eol  |  1 +
> >  tests/expected/column/table-empty-column-at-eol2 |  1 +
> >  tests/ts/column/table                            |  8 ++++++++
> >  text-utils/column.c                              | 15 ++++++++++-----
> >  4 files changed, 20 insertions(+), 5 deletions(-)
> >  create mode 100644 tests/expected/column/table-empty-column-at-eol
> >  create mode 100644 tests/expected/column/table-empty-column-at-eol2
> >
> > diff --git a/tests/expected/column/table-empty-column-at-eol b/tests/expected/column/table-empty-column-at-eol
> > new file mode 100644
> > index 000000000..948cf947f
> > --- /dev/null
> > +++ b/tests/expected/column/table-empty-column-at-eol
> > @@ -0,0 +1 @@
> > +|
> > diff --git a/tests/expected/column/table-empty-column-at-eol2 b/tests/expected/column/table-empty-column-at-eol2
> > new file mode 100644
> > index 000000000..7c4378506
> > --- /dev/null
> > +++ b/tests/expected/column/table-empty-column-at-eol2
> > @@ -0,0 +1 @@
> > +||
> > diff --git a/tests/ts/column/table b/tests/ts/column/table
> > index bd1f16f3f..e64dee746 100755
> > --- a/tests/ts/column/table
> > +++ b/tests/ts/column/table
> > @@ -116,4 +116,12 @@ ts_init_subtest "empty-column"
> >  printf ':a:b\n' | $TS_CMD_COLUMN --table --separator ':' --output-separator  ':' >> $TS_OUTPUT 2>&1
> >  ts_finalize_subtest
> >
> > +ts_init_subtest "empty-column-at-eol"
> > +printf '|' | $TS_CMD_COLUMN --separator '|' --output-separator '|' --table >> $TS_OUTPUT 2>&1
> > +ts_finalize_subtest
> > +
> > +ts_init_subtest "empty-column-at-eol2"
> > +printf '||' | $TS_CMD_COLUMN --separator '|' --output-separator '|' --table >> $TS_OUTPUT 2>&1
> > +ts_finalize_subtest
> > +
> >  ts_finalize
> > diff --git a/text-utils/column.c b/text-utils/column.c
> > index 13b39537e..64f1cf7e9 100644
> > --- a/text-utils/column.c
> > +++ b/text-utils/column.c
> > @@ -169,8 +169,9 @@ static wchar_t *local_wcstok(wchar_t *p, const wchar_t *separator, int greedy, w
> >                 return strtok_r(p, separator, state);
> >  #endif
> >         if (!p) {
> > -               if (!*state || !**state)
> > +               if (!*state) {
> >                         return NULL;
> > +               }
>
> This would be better without unnecessary curly braces.
>
> >                 p = *state;
> >         }
> >         result = p;
> > @@ -435,7 +436,7 @@ static int add_line_to_table(struct column_control *ctl, wchar_t *wcs)
> >         if (!ctl->tab)
> >                 init_table(ctl);
> >
> > -       while ((wcdata = local_wcstok(wcs, ctl->input_separator, ctl->greedy, &sv))) {
> > +       while ((wcdata = local_wcstok(wcs, ctl->input_separator, ctl->greedy, &sv)) || sv) {
>
> I don't think '|| sv' is needed.

Thanks, you are right.

Now I recall it it must be a leftover before I removed the "&&
!**data" check in local_wcstok()

>
> >                 char *data;
> >
> >                 if (scols_table_get_ncols(ctl->tab) < n + 1) {
> > @@ -452,9 +453,13 @@ static int add_line_to_table(struct column_control *ctl, wchar_t *wcs)
> >                                 err(EXIT_FAILURE, _("failed to allocate output line"));
> >                 }
> >
> > -               data = wcs_to_mbs(wcdata);
> > -               if (!data)
> > -                       err(EXIT_FAILURE, _("failed to allocate output data"));
> > +               if (wcdata) {
> > +                       data = wcs_to_mbs(wcdata);
> > +                       if (!data)
> > +                               err(EXIT_FAILURE, _("failed to allocate output data"));
> > +               } else {
> > +                       data = NULL;
> > +               }
>
> Another pair of unnecessary braces.
>
> >                 if (scols_line_refer_data(ln, n, data))
> >                         err(EXIT_FAILURE, _("failed to add output data"));
> >                 n++;
>
> If resubmitted feel free to add the following. Even if not resubmitted
> with fixes; looks pretty good.
>
> Reviewed-by: Sami Kerola <kerolasa@iki.fi>

Just sent a v2 patch.  It's simplified to only 1 line change.  Thank
you for the review ;)

Regards,
                yousong

>
> --
> Sami Kerola
> http://www.iki.fi/kerolasa/