Hi Torsten,
On Mon, 29 Aug 2022, Torsten Bögershausen wrote:
> On Mon, Aug 29, 2022 at 02:04:42PM +0200, Johannes Schindelin wrote:
> > >
> > > The choosen solution is to split code in diff.c like this
> > >
> > > strbuf_addf(&out, "%-*s", len, name);
> > >
> > > into something like this:
> > >
> > > size_t num_padding_spaces = 0;
> > > // [snip]
> > > if (len > utf8_strwidth(name))
> > > num_padding_spaces = len - utf8_strwidth(name);
> > > strbuf_addf(&out, "%s", name);
> > > if (num_padding_spaces)
> > > strbuf_addchars(&out, ' ', num_padding_spaces);
> >
> > ... this sounds like it would benefit from beinv refactored into a
> > separate function, e.g. `strbuf_add_padded(buf, utf8string)`, both for
> > readability as well as for self-documentation.
>
> Yes, but:
> All (tm) strbuf() functions use an unsigned size_t, and are not
> tolerant against passing 0 as "do nothing".
I am missing something, as this seems not to contradict the idea of
`strbuf_add_padded()`. Simply provide the desired width as a `size_t`,
compare the width of the actual added string, and if it is shorter, pad
with spaces. At no stage does this require a signed type, all involved
values are strictly non-negative.
> >
> > Also, it is unclear to me why we have to evaluate `utf8_strwidth()`
> > _twice_ and why we do not assign the result to a variable called `width`
> > and then have a conditional like
> >
> > if (width < len) /* pad to `len` columns */
> > strbuf_addchars(&out, ' ' , len - width);
> >
> > instead. That would sound more logical to me.
>
> This is caused by the logic in diff.c:
> /*
> * Find the longest filename and max number of changes
> */
> for (i = 0; (i < count) && (i < data->nr); i++) {
> struct diffstat_file *file = data->files[i];
> [snip]
> len = utf8_strwidth(file->print_name);
> if (max_width < len)
> max_width = len;
> // and later
> /*
> * From here name_width is the width of the name area,
> * and graph_width is the width of the graph area.
> * max_change is used to scale graph properly.
> */
> for (i = 0; i < count; i++) {
> /*
> * "scale" the filename
> */
> // TB: Which means either shortening it with ...
> // Or padding it, if needed, and here we need
> // another
> name_len = utf8_strwidth(name);
I was referring to this part of the commit message:
if (len > utf8_strwidth(name))
num_padding_spaces = len - utf8_strwidth(name);
Here, we evaluate `utf8_strwidth(name)`, compare it to `len`, and if the
former was smaller, we evaluate the same function call _again_.
What my feedback intended to suggest was to store the result and reuse it:
name_width = utf8_strwidth(name);
if (name_width < len)
num_padding_spaces = len - name_width;
Ciao,
Dscho
