Re: [PATCH v5 04/10] grep/icase: avoid kwsset on literal non-ascii strings

> On Thu, Jan 28, 2016 at 6:56 AM, Nguyễn Thái Ngọc Duy <pclouds@gmail.com> wrote:
>> When we detect the pattern is just a literal string, we avoid heavy
>> regex engine and use fast substring search implemented in kwsset.c.
>> But kws uses git-ctype which is locale-independent so it does not know
>> how to fold case properly outside ascii range. Let regcomp or pcre
>> take care of this case instead. Slower, but accurate.
>>
>> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
>> ---
>> diff --git a/grep.c b/grep.c
>> @@ -398,12 +399,16 @@ static int is_fixed(const char *s, size_t len)
>>  static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
>>  {
>> +       int icase_non_ascii;
>>         int err;
>>
>>         p->word_regexp = opt->word_regexp;
>>         p->ignore_case = opt->ignore_case;
>> +       icase_non_ascii =
>> +               (opt->regflags & REG_ICASE || p->ignore_case) &&
>> +               has_non_ascii(p->pattern);
>>
>> -       if (is_fixed(p->pattern, p->patternlen))
>> +       if (!icase_non_ascii && is_fixed(p->pattern, p->patternlen))
>
> These double negatives (!non_ascii) here and in patch 5/10 are
> difficult to grok. I wonder if a different name, such as
> icase_ascii_only would help.