Re: [PATCH v12 05/13] ref-filter: implement an `align` atom

> Implement an `align` atom which left-, middle-, or right-aligns the
> content between %(align:..) and %(end).
>
> It is followed by `:<width>,<position>`, where the `<position>` is
> either left, right or middle and `<width>` is the size of the area
> into which the content will be placed. If the content between
> %(align:) and %(end) is more than the width then no alignment is
> performed. e.g. to align a refname atom to the middle with a total
> width of 40 we can do: --format="%(align:middle,40)%(refname)%(end)".
>
> We now have a `handler()` for each atom_value which will be called
> when that atom_value is being parsed, and similarly an `at_end`
> function for each state which is to be called when the `end` atom is
> encountered. Using this implement the `align` atom which aligns the
> given strbuf by calling `strbuf_utf8_align()` from utf8.c
>
> This is done by assigning a 'handler' function to each atom_value and
> a related 'at_end' function for each state. The align_handler()
> defined uses strbuf_utf8_align() from utf8.c to perform the alignment.
>
> Add documentation and tests for the same.
>
> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
> ---
> diff --git a/ref-filter.c b/ref-filter.c
> index 74532d3..ecbcc5a 100644
> --- a/ref-filter.c
> +++ b/ref-filter.c
> @@ -626,6 +638,36 @@ static inline char *copy_advance(char *dst, const char *src)
>         return dst;
>  }
>
> +static void align_handler(struct ref_formatting_state *state)
> +{
> +       struct align *align = (struct align *)state->cb_data;
> +       struct strbuf s = STRBUF_INIT;
> +
> +       strbuf_utf8_align(&s, align->position, align->width, state->output.buf);
> +       strbuf_reset(&state->output);
> +       strbuf_addbuf(&state->output, &s);
> +       free(align);
> +}