Re: [PATCH v6 01/10] ref-filter: introduce 'ref_formatting_state'

> On Tuesday, July 28, 2015, Karthik Nayak <karthik.188@gmail.com> wrote:
>> Introduce 'ref_formatting' structure to hold values of pseudo atoms
>> which help only in formatting. This will eventually be used by atoms
>> like `color` and the `padright` atom which will be introduced in a
>> later patch.
>
> Isn't this commit message outdated now that you no longer treat color
> specially and since the terminology is changing from "pseudo" to
> "modifier"? Also, isn't the structure now called
> 'ref_formatting_state' rather than 'ref_formatting'?

>
>> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
>> ---
>> diff --git a/ref-filter.c b/ref-filter.c
>> index 7561727..a919a14 100644
>> --- a/ref-filter.c
>> +++ b/ref-filter.c
>> @@ -620,7 +622,7 @@ static void populate_value(struct ref_array_item *ref)
>>                 const char *name = used_atom[i];
>>                 struct atom_value *v = &ref->value[i];
>>                 int deref = 0;
>> -               const char *refname;
>> +               const char *refname = NULL;
>
> What is this change about? It doesn't seem to be related to anything
> else in the patch.
>

>>                 const char *formatp;
>>                 struct branch *branch = NULL;
>>
>> @@ -1190,30 +1192,47 @@ void ref_array_sort(struct ref_sorting *sorting, struct ref_array *array)
>> +static void print_value(struct atom_value *v, struct ref_formatting_state *state)
>> +{
>> +       struct strbuf value = STRBUF_INIT;
>> +       struct strbuf formatted = STRBUF_INIT;
>> +
>> +       /*
>> +        * Some (pesudo) atoms have no immediate side effect, but only
>> +        * affect the next atom. Store the relevant information from
>> +        * these atoms in the 'state' variable for use when displaying
>> +        * the next atom.
>> +        */
>> +       apply_formatting_state(state, v, &value);
>
> The comment says that this is "storing" formatting state, however, the
> code is actually "applying" the state. You could move this comment
> down to show_ref_array_item() where formatting state actually gets
> stored. Or you could fix it to talk about "applying" the state.
> However, now that apply_formatting_state() has a meaningful name, you
> could also drop the comment altogether since it doesn't say much
> beyond what is said already by the function name.
>

>> +       switch (state->quote_style) {
>>         case QUOTE_NONE:
>> -               fputs(v->s, stdout);
>> @@ -1254,9 +1273,26 @@ static void emit(const char *cp, const char *ep)
>> +static void reset_formatting_state(struct ref_formatting_state *state)
>> +{
>> +       int quote_style = state->quote_style;
>> +       memset(state, 0, sizeof(*state));
>> +       state->quote_style = quote_style;
>
> I wonder if this sledge-hammer approach of saving one or two values
> before clearing the entire 'ref_formatting_state' and then restoring
> the saved values will scale well. Would it be better for this to just
> individually reset the fields which need resetting and not touch those
> that don't?
>
> Also, the fact that quote_style has to be handled specially may be an
> indication that it doesn't belong in this structure grouped with the
> other modifiers or that you need better classification within the
> structure. For instance:
>
>     struct ref_formatting_state {
>         struct global {
>             int quote_style;
>         };
>         struct local {
>             int pad_right;
>         };
>
> where 'local' state gets reset by reset_formatting_state(), and
> 'global' is left alone.
>
> That's just one idea, not necessarily a proposal, but is something to
> think about since the current arrangement is kind of yucky.
>

>> +}
>> +
>>  void show_ref_array_item(struct ref_array_item *info, const char *format, int quote_style)
>>  {
>>         const char *cp, *sp, *ep;
>> +       struct ref_formatting_state state;
>> +
>> +       memset(&state, 0, sizeof(state));
>> +       state.quote_style = quote_style;
>
> It's a little bit ugly to use memset() here when you have
> reset_formatting_state() available. You could set quote_style first,
> and then call reset_formatting_state() rather than memset(). Or,
> perhaps, change reset_formatting_state(), as described above, to stop
> using the sledge-hammer approach.
>