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

[Sami Kerola <kerolasa@iki.fi>]

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.

>                 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>

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